Page 1
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
Page 9
Page 10
Page 11
Page 12
Page 13
Page 14
Page 15
Page 16
Page 17
Page 18
Page 19
Page 20
Page 21
Page 22
Page 23
Page 24
Page 25
Page 26
Page 27
Page 28
Page 29
Page 30
Page 31
Page 32
Page 33
Page 34
Page 35
Page 36
Page 37
Page 38
Page 39
Page 40
Page 41
Page 42
Page 43
Page 44
Page 45
Page 46
Page 47
Page 48
Page 49
Page 50
Page 51
Page 52
Page 53
Page 54
Page 55
Page 56
Page 57
Page 58
Page 59
Page 60
Page 61
Page 62
Page 63
Page 64
Page 65
Page 66
Page 67
Page 68
Page 69
Page 70
Page 71
Page 72
Page 73
Page 74
Page 75
Page 76
Page 77
Page 78
Page 79
Page 80
Page 81
Page 82
Page 83
Page 84
Page 85
Page 86
Page 87
Page 88
Page 89
Page 90
Page 91
Page 92
Page 93
Page 94
Page 95
Page 96
Page 97
Page 98
Page 99
Page 100
Page 101
Page 102
Page 103
Page 104
Page 105
Page 106
Page 107
Page 108
Page 109
Page 110
Page 111
Page 112
Page 113
Page 114
Page 115
Page 116
Page 117
Page 118
Page 119
Page 120
Page 121
Page 122
Page 123
Page 124
Page 125
Page 126
Page 127
Page 128
Page 129
Page 130
Page 131
Page 132
Page 133
Page 134
Page 135
Page 136
Page 137
Page 138
Page 139
Page 140
Page 141
Page 142
Page 143
Page 144
Page 145
Page 146
Page 147
Page 148
Page 149
Page 150
Page 151
Page 152
Page 153
Page 154
Page 155
Page 156
Page 157
Page 158
Page 159
Page 160
Page 161
Page 162
Page 163
Page 164
Page 165
Page 166
Page 167
Page 168
Page 169
Page 170
Page 171
Page 172
Page 173
Page 174
Page 175
Page 176
Page 177
Page 178
Page 179
Page 180
Technical guidance for designers specifiers installers Second Edition Lighting for signs display Lighting for signs and display Technical guidance for designers specifiers and installers Published by Vink Lighting Solutions March 2015 3 Contents 01 Introduction 6 02 What is light 9 03 Colour and how we see it 10 Colour Systems 12 Colour Perception 14 Colour Measurement 16 04 Characteristics of Light 24 Quantities and units 24 The inverse square law 25 Cosine law 26 Light dispersion 27 Reflection Transmission Refraction and Total Internal Reflection 28 Fresnels Equations 30 Refractive Index 31 Snells law 32 Total Internal Reflection 34 05 LED Technology 35 History of LEDs 36 LED packages 37 Optical Lens Technology 40 LEDs in signs 43 06 Power Supplies 45 Basics of Electricity Ohms Law 46 Introduction to LED Drivers 53 Types of LED Drivers 57 4 Contents 07 Controls Dimming 60 How LEDs are dimmed and their effects 64 Control Signals 66 08 Performance Reliability 68 Thermal Management 69 Lumen Depreciation 71 Colour Shift 73 LED Binning 74 09 Sign Design 77 Material Selection 82 Layout drawings and populations 89 Avoiding contributing to light pollution 91 10 Applications 93 LED Fitting into letters 94 Back-lit Lightboxes 99 Edge-lit lightboxes 103 LED Edge-lit panels 105 LED Floodlights 107 Overhead LED trough lighting 110 11 Standards Testing Classification 111 BS 559 112 HD 60364 and BS 7671 113 IEC 62347-2-13 114 IEC 62384 115 LM79 117 5 Contents LM80 128 EN 50107-1 133 EN 61050 EN 61347-2-10 EN 50107-2 and EN 50143 134 CE Marking 135 IP Ratings 136 12 Legislation Guidelines 138 The E.C.A. Scheme 139 RoHS Compliance 143 BREEAM 145 Health and Safety 147 The Weee Directive 152 Advertising Consent 153 13 Neon and Cold Cathode 157 14 Glossary 162 15 Useful contacts 175 6 01 Introduction Two years after the publication of the first edition of Lighting for Signs Display in 2013 Im happy to find myself writing this introduction to the second issue. The decision to publish a second edition has been the result of two factors the extremely positive response to the first issue and the continuing pace of progress within our industry. The need to keep up-to-date with technology standards and legislation has also resulted in the publication of this edition in the e-book format which will allow more regular updates as required as well as easy access for our readers via our website. You can also download a copy to your own PC to refer to whenever you need it. Our intention from the outset was to provide a valuable textbook resource for sign makers and this new issue is even more comprehensive than the first with updates and additions to almost every chapter. Youll also find a new chapter covering Neon and Cold Cathode lighting as these technologies are enjoying something of a resurgence driven to a great extent by nostalgia and the desire for retro designs. It all adds to a vibrant and diverse industry of which were delighted to be a part. Nostalgia apart the last decade has seen a sea change in lighting for all applications from domestic and commercial interior lighting to street lighting sports stadia industrial plants automotive lighting and elsewhere. Ongoing investment in the development of LED technology by the major lighting manufacturers has ensured that todays LEDs offer an impressive combination of high light output long working life and very low energy consumption. The sign industry has been quick to embrace this new technology and the benefits it provides however application knowledge relating to LEDs is still in relatively short supply. 7 01 Introduction Ever since the inception of hand- formed Neon tubing lighting signs and displays has seemed like something of a black art to the uninitiated. Now with LED technology having all but taken over this sector achieving effective and consistent results with illuminated signs has not become any more straightforward. In fact there are even more variables and potential pitfalls. For example the choice of one manufacturers LED over another can dramatically affect the appearance of the illuminated sign even if the specification of the LED module appears outwardly similar. The same can be said of material choice. Similar translucent or coloured acrylic sheet products can display hugely varying results. Then there is the subject of compliance. In recent years new legislation and initiatives have been introduced covering energy usage recycling health safety and other subjects... just waiting to catch out the unwary. By compiling this book Vink Lighting Solutions Europes leading specialist in sign lighting products hope to develop the general knowledge base of illuminated sign makers designers and specifiers to provide knowledge that will help them differentiate and add value to their signs. help sign makers to work within current legislation to avoid compliance issues. help end users achieve improved presentation of their brands. make a contribution to global emissions targets and reductions in light pollution. This subject is so broad that no one individual could have covered disciplines ranging from colour perception of the human eye to colour measurement electrical power supplies LED technologies sign design and more... from Application knowledge relating to LEDs in signs is still in relatively short supply. 8 01 Introduction the theoretical and scientific to practical nuts and bolts advice on installing signs and the book itself is a compilation of contributions from a number of individuals with different experience and skill sets. We have aimed to present information as clearly as possible and with the least use of jargon so that technical subjects can be communicated effectively to an audience which will not necessarily come from a technical background. Despite our best efforts with this second edition you may find some of the topics covered have not been fully explained. Needless to say if this is the case and you need further information or support the design and specification team at Vink Lighting Solutions will be happy to help. We hope that you find the information in this book to be of use. David Foreman Vink Lighting Solutions ...the book itself is a compilation of contributions from a number of individuals with different experience and skill sets. 9 02 What is light In recent times the technical aspects of light colour light sources and their application in signs have become more important as LED technology has become more prevalent and end user customers are demanding greater colour accuracy and consistency. Light can be viewed as either a series of particles called photons or it can be viewed as a waveform. The view taken is usually dependent on the application and in our case a waveform is the most useful way in which to study the physics of light. Visible light forms a very small part of the electromagnetic spectrum. This ranges from radio waves through the infrared to visible and on into ultraviolet x-rays and gamma radiation. Visible light has wavelengths between 380 and 780 nanometres see Figure 1. A nano metre is 10x-9 metres or 11000000000 metres. Pretty small. Further explanation is given in the following chapters Chapter 3 Colour and how we see it gives some background information on vision colour and how it can be measured and compared. Chapter 4 Characteristics of light contains some FAQs denitions and explanations of mathematical calculations relevant to the sign industry and particularly to the application of LEDs to backlit signs. 400 450 500 550 600 650 700 Figure 1 The visible light spectrum wavelengths nanometres 10 03 Colour and how we see it To better understand the optimisation of LEDs and colour in signs we need to have some understanding of colour vision colour measurement and the application of the knowledge. Colour can only exist when three components are present a viewer an object and light. Emitted or transmitted and reflected light White light is made up of all colours in the visible spectrum. Light emitted or transmitted only contains the colours characteristic of the light source or transmission medium. These may be all colours e.g. sunlight or near monochrome e.g. yellow. When white light hits an object the object absorbs some of the colours and reflects others. This reflected light is the colour observed by the viewer. The eye Light enters through the cornea of the eye it is controlled by the iris and then focused by the lens onto the retina. See Figure 2 overleaf. The light passes through the effectively transparent nerve structures before reaching the light sensitive rods and cones at the right of the picture. The more numerous rod receptors can only sense light and shade and are used for night vision more sensitive motion detection and peripheral vision. The cones are used for colour vision and the highest acuity. Early theories of vision were based on the detection of the three colours red green and blue and their relative intensities. In 1965 it was confirmed by experiment that there are three types of cones each of which is sensitive to either short medium or long wavelengths or to put it more simply Red Green and Blue light. When we see a green object the green cones are excited more than the red or blue cones and related signals sent to our brain. Our brain interprets those signals as green. 11 03 Colour and how we see it Figure 2 The human eye Cone cell Rod cell Retina Optic nerve Ciliary body Iris Pupil Lens Sclera Choroid Cornea 12 Colour Systems The brain works in much the same way as a computer or TV monitor by mixing Red Green and Blue light to create virtually any colour in the visible spectrum. This RGB process is known as Additive Colour Mixing because it works by effectively adding light to a dark background Figure 3. Figure 3 Additive Colour Mixing RGB Another process more applicable to printing as opposed to light sources is Subtractive Colour Mixing. This works by adding and overlaying pigments to a white background This process often uses CMYK Cyan Magenta Yellow and Black inks. Black ink is added because CMY alone cannot produce a true black. The K stands for Key a printing term for process black. 13 03 Colour and how we see it Colour Systems Subtractive processes are more susceptible to ambient light because this light is what becomes reflected or absorbed to produce the colours. This explains why digitally printed images back-lit with different colour warmth LEDS can produce markedly different effects. In this case the pigments transmit or absorb various wavelengths of light Figure 4. Figure 4 Subtractive Colour Mixing CMYK 14 Colour Perception Sir Isaac Newton is well known for his work on mechanics. His laws of motion are fundamental to physics and hence modern life. However he was also deeply involved in light and optics. Here are just three conclusions that he drew which are key to our understanding of the lighting of signs. Spectrum so that there appeared as many degrees of colours as there were sorts of rays differing in refrangibility. Subjective The rays to speak properly are not coloured. In them there is nothing else than a certain power and disposition to stir up a sensation of this or that colour. Important colours in the object are nothing but a disposition to reflect this or that sort of rays more copiously than the rest. This final point in particular is key to the lighting of signs and highlights reflected versus emitted or transmitted light. Newton was absolutely right even though all he had was a simple prism to work with. A good light source with high CRI see P20 has significant quantities of red blue and green light within it. The best have the correct blend of all colours. When we see a green object it is because it has absorbed all but the green light from the source and reflected only green. Our eyes only receive green and the green cones are more excited than the red and blue as before. If the objects we are viewing have different colours each absorbs or reflects accordingly and we see the various reflected colours if they were available from the light source Our eyes evolved over millions of years under sunlight and therefore when sunlight illuminates objects we see all colours equally well. By contrast old sodium street lights emit only 2 very close yellow peaks see Figure 7 on Page 19 and subsequently many colours appear grey see figure opposite. 15 03 Colour and how we see it Colour Perception Reflected light depends on incident light and material characteristics. There is a system for measuring the colour of objects by reflection based on shining a known source on the surface and measuring the reflected light. For comparisons therefore we need to use a standard lamp for illumination of the reflecting object. The source selected depends on the environment and application. e.g. If a sign is inside a shopping mall the reflected colour of the sign will probably depend on a combination of sunlight and the lamps used in the building. In contrast a sign outside will always be viewed under sunlight during the day. Reproducing sunlight is extremely difficult so CIE has designated lamps with certain spectra as standard illuminants. With emitted or transmitted light such as a backlit sign a similar process occurs. In this case we see the spectrum of the light being emitted from the lamps and subsequently transmitted by the sign face and not that which has been reflected. Old sodium streetlights emit only yellow light making many colours appear grey 16 Colour Measurement There are many systems of colour measurement. The most commonly used and probably most relevant to our industry is a theory based system developed in 1931 by Commission International de lEclairage CIE. CIE Colour Measurement At that time the CIE developed three colour matching functions which approximate the sensitivities of the three types of cones in the eye red green and blue. If the spectrum of the source is multiplied by those functions and further mathematical transformations applied a 3 co- ordinate system X Y Z and x y z can be generated. It was designed such that xyz1 so we only need x and y to define a colour within the CIE 1931 colour space. The theory of the three colour matching functions was confirmed in 1965. Other systems of colour measurement that you might come across include- CIE 1976 L u v L a b. Most are based upon the 1931 system. Colour systems for printing include RGB and CMYK. There are complex transforms available from some systems to others. 17 03 Colour and how we see it Colour Measurement Figure 5 is a representation of the CIE 1931 xy co-ordinate diagram. The x co-ordinate along the bottom y co-ordinate up the side and the various colours in the rounded triangle in the middle. Red green and blue at the corners and saturated colours related to wavelength nm around the edge. Whites in the middle. The curve running through the middle is known as the Black body locus and represents a theoretical series of points used for classifying light sources by their Correlated Colour Temperature or CCT. Note these classifications are lines perpendicular to the black body Locus - lines not points - so 2 sources with the same CCT can be different colours In the diagram below the CCT lines for 1500K 2000K 2500K 3000K 4000K 6000k and 10000K are labelled. K stands for degrees on the Kelvin temperature scale. 0 degrees Celsius 273 Kelvin. Figure 5 CIE 1931 xy co-ordinate diagram 18 03 Colour and how we see it Colour Measurement Spectra We are all familiar with the rainbow and the effect a prism has. Modern instruments use a diffraction grating and CCD to record spectra. From the spectrum you can calculate the x and y CCT Colour Rendering Index CRI and many other parameters related to the light source. The following are some examples of spectra and a brief explanation of each. Figure 6 below shows the spectrum of the sky on a grey day. Very little at the UV end but plenty of light from blue right through to red. Figure 6 Spectrum reading from the sky on a grey day Figure 7 overleaf shows the spectrum of a sodium street lamp. Not a lot to it really apart from the massive yellow peak. You can see if you illuminate something with this lamp you will see no colours reflected other than yellow. Anything that does not reflect yellow well will appear grey. 19 03 Colour and how we see it Colour Measurement Figure 7 Spectrum reading from a sodium street lamp Figure 8 below is the xy plot of that sodium lamp and the parameters measured. Notice the point is right on the edge of the diagram indicating a saturated colour and that the colour purity is 97.2 . Figure 8 Xy plot from a sodium street lamp 20 03 Colour and how we see it Colour Measurement Parameters from spectra There are a number of parameters that can be calculated from the spectrum of a light source that can be useful to sign makers. These include- Co-ordinates x and y these define the colour. CCT Correlated Colour Temperature allows us to classify light sources with reservations. We have seen how a particular CCT is actually a line a series of points so does not define the colour. If the CCT also sits on the black body locus we have defined the colour. Some LED modules that we have measured are near enough on the black body locus. Other manufacturers modules may not be. Dominant Wavelength A theoretical figure equal to the wavelength of light at the perimeter of the diagram in line with the colour point and the centre of the diagram at x0.3333 y0.3333. Used in conjunction with Colour Purity to describe saturated colours. Colour Purity expressed as - a measure of the bandwidth or purity of the colour measured. For monochrome applications we would want to see figures above 90 . If a corporate colour is a pure monochrome blue for example why waste energy lighting it with white when you could light it with monochrome blue LED Clearly this does not apply to none monochrome colours purple for example or pastel shades or mixed colours e.g the yellow and orange of Shell. Dominant Wavelength and Colour Purity allow us to optimise applications for monochrome sources red amber yellow green blue. Colour Rendering Index CRI a measure of relative suitability of a light source for multiple colour performance. This is a complex issue currently under debate with respect to LEDs. It has been shown that RGB LED clusters do not perform well in the standard test for CRI even if they actually appear to perform well in practice. Alternate procedures are under development Colour Quality Scale. However we do not intend to apply 21 03 Colour and how we see it Colour Measurement CRI to monochrome LEDs and are only concerned with back lighting so accuracy of CRI measurement is less critical. For now for signs we should focus on the overall parameter Ra. This is quoted between 0 to 100 where 100 would be all colours perfectly viewed when illuminated by the source measured. We can use CRI in our industry whereas strict lighting applications might need another parameter such as Colour Quality Scale. Some typical values of CRI of various light sources would be- Low pressure sodium lamp about 5 High pressure sodium lamp about 24 Old technology fluorescent 50 to 75 Tri-phosphor fluorescent 70 to 90 LED Old technology 25 LED recent technology up to 80 and above Colour differences We have already explained that there are many more recent systems for colour and hence colour difference measurement. However they tend to be complex and over engineered for our sign industry needs. We will concern ourselves with the 1931 x y system and the resultant MacAdam ellipses. MacAdam established that people could perceive colour differences to differing amounts depending on where the colour is in the CIE diagram. Further he found that on the CIE 1931 diagram the differences plotted as ellipses and not circles. MacAdam Ellipses Figure 9 is a representation of MacAdam ellipses drawn on the CIE 1931 Diagram. Note that the ellipses in the representation are magnified by a factor of 10. So in reality they are actually very small. They are referred to as Just Noticeable Differences or JNDs. Also note that in practice getting two 22 03 Colour and how we see it Colour Measurement fluorescent lamps for example within 3 JNDs is very difficult. For signs differences of 5 or more JNDs might not be noticeable to the general public depending on the circumstances. Figure 9 MacAdam ellipses on the CIE 1931 diagram 1.0 1.00 0.8 0.8 0.6 0.6 0.4 0.4 0.2 0.2 23 03 Colour and how we see it Colour Measurement Typical Colour Difference Chart Figure 10 is a typical chart showing the difference between a 50K LED and the CIE defined 5000K point on the black body locus. With the correct equipment and a bit of effort we can produce charts comparing any 2 points on the diagram. For example the difference in colour of a key element of a transparency when backlit with 3200K compared with 4100K LEDs. We can then optimise the LED system to the circumstances of the sign installation. Figure 10 typical colour difference chart 24 04 Characteristics of Light Quantities and units Luminous flux The total amount of light. Often specifically the total light being emitted from a source in all directions. Unit Lumen lm. Luminous intensity The fraction of the luminous flux leaving a source in a given direction. Unit Candela cd. Luminance Flow of light in a given direction. Often more specifically the light being emitted from a surface. Unit Candela per square metre cdm2 Illuminance Luminous flux falling on a surface. Unit Lux E. Efficiency Power out expressed as a percentage of power in. Efficiency Light power out in Watts 100 Electrical power in in Watts Efficacy The light emitted per unit of power in. Unit Lumen per Watt lmW or Candela per metre squared per Watt cdm2 W. This section contains some FAQs denitions and explanations of mathematical calculations relevant to the sign industry and particularly to the application of LEDs to backlit signs. 25 The inverse square law The inverse square law applies to many issues. However it is relevant to us when we consider the distance between the source and the sign face and the distance from the sign to the observer. For lament lamps or LEDs without optics we can assume a point source is involved. The same does not apply to LEDs with optics linear uorescent or cold cathode lamps. The law states that the illumination received on a surface from a light source is inversely proportional to the square of its distance from the source. Practically this means that if we have 1000 Lux at a point from the light source if we move to twice as far away we will have 250 Lux 2x24 10004250 and if we move 10 times the distance away we will have 10 Lux 10x10100 100010010. Mathematically- E I h2 Where E is Illuminance in Lux I is Luminous Intensity in Candela and h is the perpendicular distance from the source to the surface in metres. Example A 1600 cd point light source is placed 2 metres above a surface. What is the Illuminace at the surface. Solution E 160022 16004 400 Lux. 26 Cosine law The cosine law applies when the area we are considering is not perpen- dicular to the light coming from the source. e.g. The light falling on the back of a sign face from an LED source. Again it applies to a point source and in this case we can only consider LEDs with no lens as a point source. Figure 11 Cosine law Figure 11 shows a point light source at S with a luminous intensity of I above a plane including points O and P. The Illuminance at O is given by EO Ih2 . The Illuminance at P is given by EP ICosqd2 . This formula combines both the Inverse Square Law and the Cosine Law. This means for a bare LED no lens The light intensity is high in the middle and drops off by the cosine of the angle. A slow drop initially and then getting steeper. This highly variable light intensity as you move away from the LED across the sign face means that light spots are difficult to avoid. This combined formula is applicable when we consider- 1 Spacing of LEDs on modules and module spacing. 2 Spacing of lines of modules. 3 Spacing of spotlights. 27 Light dispersion Most early LED modules incorporated bare LED chips. As modules became more sophisticated clear acrylic or polycarbonate covers were incorporated to protect the delicate phosphors and improve longevity. However this did mean slightly lower light output. As chips became more efficacious this light loss became less important but it was realised the cover could be act as an optical lens as well as a protective cover. In these more sophisticated LED modules incorporating optics the clear moulding is used to modify and optimise the spread of light from the chips along with providing protection. This makes the assumption of a point source see under Cosine law invalid and the calculations can become far more complicated. Further information is given in the chapter LED Technology in the paragraphs on Optical Lens Technology. It is not just the LED module that can impact evenness and light output from the front face of a sign. In some cases the surface brightness of backlit white acrylic has been doubled by changing the acrylic to one designed for use with LEDs. The client can then either have a sign with twice the surface luminance or a sign with the same luminance but half the running cost. Also the correct selection of LED colour and LED coloured acrylic can substantially improve the normally very low light output from saturated coloured acrylics. In some cases this can be up to a factor of 9 times the luminance. 28 Below are some notes on some of the optical phenomena which occur inside an illuminated sign. Inside the Sign Case When light strikes an opaque surface the inside of the sign box or letter for example some of the light is absorbed and wasted as heat and some is reflected back into the box and may still be useful. Again depending on the characteristics the amounts can vary widely. To maximise the efficacy of a sign we need to maximise the reflection and minimise the absorption by the sign case. To do this we can use a matt white finish or the materials from vinyl suppliers designed for this purpose. We should use a diffuser such as matt paint and not use bare metal or gloss paint as this can lead to uneven illumination of the face. At the front face of the sign Every time light strikes an interface between two media air and acrylic for example three things happen- 1 A percentage of the light is absorbed and wasted as heat 2 A percentage of the light is reflected and 3 A percentage of the light is transmitted. Depending on the geometry particularly the angle of incidence of the light the characteristics of the materials and the characteristics of the light these percentages vary widely. For a translucent front face such as acrylic or flexible vinyl different processes occur at the inside and outside surfaces of the material. At the inside surface a proportion of the incident light is transmitted and diffused and a proportion is reflected. The amounts depend on the colour of the light the colour of the face and on both the refractive index of the face and the angle of incidence of the light. When the light is perpendicular Reflection Transmission Refraction and Total Internal Reflection 29 04 Characteristics of Light Reflection Transmission Refraction and Total Internal Reflection to the face the maximum amount is transmitted. Angles of incidence are measured from this perpendicular to the surface also known as normal to the surface. As the angle of incidence increases the amount of light transmitted and diffused and hence seen by the observer reduces as the Refractive Index and Fresnels Equations come into play see overleaf. At the outside surface the same processes take place with the addition of a further effect that of Total Internal Reflection see page 34. 30 Fresnels Equations These are complex equations which can be used to calculate the percentage of light reflected or transmitted at interfaces with different refractive indexes and angles of incidence. For air and acrylic the results are such that as light strikes the inside front face of the sign face the approximate percentage transmitted or reflected at various angles of incidence is given in the table below- Angle of incidence to perpendicular Approximate percentage transmitted Approximate percentage reflected 20 95 5 40 92 8 60 82 18 80 45 55 This is demonstrated well for those old enough to remember it by the opening credits of the TV programme Harry Worth reflection in the shop window where he appears to have both feet off the ground at the same time. Also if you consider looking out of a window straight on you see outside clearly and little inside at an acute angle you can see a reflection of the interior as well as the external view. Projecting light onto the rear of the sign face at too large an angle of incidence therefore reduces efficacy as more is reflected back into the sign where more will be absorbed and converted into heat. 31 Refractive Index The Refractive Index of a material is a measure as to how much it will slow down light as it passes through which has the effect of bending the light path as it passes from one material to another. Air has a refractive index of 1.0 and acrylic has a refractive index of 1.49. 32 Snells law This law deals with the way light is bent as it passes between two media of different refractive index. The Refractive index is a measure as to much a given material will slow down the speed that light passes through it which has the effect of bending the path that the light travels as it passes from one material and through another. Air has a Refractive index of 1 and Acrylic has a Refractive index of 1.49. Snells Law is a formula which calculates how much the light will bend based on the angle it travels from one material to another and the Refractive index of each material. As light passes the border between different materials depending upon the relative refractive indices of the two media the light will either be refracted to a lesser angle or a greater one. These angles are measured with respect to the normal line represented perpendicular to the boundary. In the case of light traveling from air into water light would be refracted towards the normal line because the light is slowed down in water light traveling from water to air would refract away from the normal line. Figure 12 Incident light ray from light source 33 04 Characteristics of Light Snells law In general terms the way light refracts through different materials and the consequent angles of refraction will have little effect on the look of a nished sign but it may be worth taking into consideration where the sign has a clear acrylic or polycarbonate protective cover and the back lighting product is placed only in specic portions of the sign. Also in general terms the direction the light is emitted from the LED and the subsequent reflection refraction and transmission can impact on the efficacy or the sign. For the ray leaving the acrylic and entering the air Snells law states that nc sin c ni sin i Where- nc refractive index of acrylic and c the angle between the ray in the acrylic and the normal and ni refractive index of air and i the angle between the ray in the air and the normal. Now the refractive index of air is effectively 1.0 and the refractive index of acrylic is 1.49. Rearranging the above sin c ni sin i nc 34 Given Snells law see page 32 when light passes from a higher refractive index material into a lower there comes a point when the angle of incidence reaches a critical angle and the light does not pass out of the medium but is reected internally. For acrylic with a refractive index of 1.49 and air refractive index 1.0 this angle is 42.8 degrees to the normal. So any light within the front face material which strikes the front face of acrylic at greater than 42 degrees to the normal will be reected back into the acrylic and the sign box and bounce around inside until either it is absorbed or hits the front face at a suitable angle to be transmitted. Note that at each reflection some light is absorbed by the walls and back of the sign and it dwindles away as waste heat. This corresponds to an LED eld angle defined as the angle between the points were the light intensity is 50 of the maximum either side of normal of about 90 degrees. The real situation with opal or coloured acrylic is much more complicated due to the diffusing effects of these materials. However this clearly means that an LED module with a beam angle of 180 degrees will waste more light through total internal reection than one with a beam angle of 150 degrees. Total Internal Reflection 35 05 LED Technology LEDs Light Emitting Diodes do all kinds of different jobs and are found in all kinds of devices. Among other things they form numbers on digital readouts light up watches and indicate when appliances are turned on. They can be used together to form images on television screens or provide illumination for automobile headlights building interiors street lights and yes signs and displays. LEDs are effectively miniature light bulbs that fit easily into an electrical circuits. But unlike traditional incandescent bulbs they dont have a filament that will burn out. They generate significantly less heat than incandescent bulbs allowing design benefits in all kinds of applications. LEDs are illuminated by the movement of electrons in a semiconductor material and they last just as long as a standard transistor. This means that the lifespan of an average LED surpasses the life of an incandescent bulb by thousands of hours. Over the last decade LED products for the sign industry have been developed and refined so that today signmakers can choose from a wide range of different technologies to suit different applications and budgets. This chapter contains a brief outline of the different technologies available and how lenses can affect the performance of LEDs in signage applications. 36 History of LEDs In 1907 Henry Joseph Round whilst working at the Marconi Laboratories in England discovered the phenomenon known as Electroluminescence. He discovered that when an electrical current was passed through a crystal of Silicone Carbide it produced a faint yellowish glow. Different colours could be produced using different crystals and different Voltages. The first practical use of LEDs did not occur until 1961 when Bob Biard and Gary Pittman were working together on a project for Texas Instruments to develop Gallium Arsenide diodes. They found that these diodes emitted significant light in the infrared region. By 1962 the first practical use of an LED was developed by Nick Holonyack jr. at the GE Laboratories in the U.S. This development made use of Red LEDs as laser diodes in applications such as CD readers. The Monsanto Company was the first organisation to mass-produce visible LEDs using Gallium Arsenide Phosphide to produce red LEDs suitable for indicators. In 1968 Hewlett Packard introduced these LEDs as numeric displays in early calculators. In 1972 Dr. M.George Craford working at Monsanto developed a yellow LED and succeeding in significantly increasing the brightness of red LED. The first high brightness blue LED was developed in 1993 by Professor Shuji Nakamura at the Nichia Corporation in Japan. By 1995 this breakthrough heralded the development of the first low power white LED. By 2000 LEDs were being supplied commercially into the signage industry for use in built-up channel letters as a replacement for Cold Cathode and the development of high brightness white LEDs in 2005 by the Nichia Corporation has helped to install LED as the main product of choice for most commercial illuminated signs today. 37 LED packages Over time LED packages for signage applications have continued to develop as demands have increased for higher brightness lower energy consumption and improved reliability. Packages can be divided into four main categories as follows 5mm Domed LED Modules Superflux 5mm LED Modules Surface Mount Device SMD LED Chip on Board COB LED 5mm Domed LED Modules With this type of module a 5mm LED is based on two leads and an epoxy resin domed housing. The chip is placed on the cathode lead with a reflector cup and then connected with a bond wire to the anode lead. The light is bundled by the reflector and the lens shape of the epoxy. The sole advantage for this type of LED is that it is inexpensive to produce and so would be suitable for short term indoor applications. The disadvantages are low power and low light output narrow beam angle sensitivity to temperature extremes and susceptibility to shock and vibration damage. 5mm diodes typically have a lifetime of 20000 hours or less to 70 Lumen depreciation. Superflux 5mm LED Modules A Superflux or Piranha LED is very similar to an epoxy 5mm domed LED but with a lower profile square shape with two anode and two cathode leads for better thermal dissipation. 38 05 LED Technology LED packages Advantages with this type of LED are low cost production higher power and light output than 5mm diodes beam angles up to 130 degrees and a more robust package with a lower profile than the 5mm diode. Disadvantages include sensitivity to temperature extremes and lower light outputs compared to SMD or COB packages. Surface Mount Device SMD LED SMD is a technology where the chip is placed directly into a lead frame thermoplastic moulding combination surrounded by a reflector and encased in epoxy or silicone resin in order to protect the diode from the environment. An SMD is generally more compact and has better heat management than a 5mm diode leading to higher light output per diode with a much improved lifetime. Beam angles of up to 140 degrees are possible without secondary optics. Whilst SMDs are more expensive than 5mm diodes they are generally more robust and far less susceptible to shock and vibration damage. Chip on Board COB LED Chip on Board technology has the LED chip placed directly onto a printed circuit board. Chip on Board LEDs have far better thermal management properties and light outputs per diode compared to other LED packages. Beam angles of up to 140 degrees are possible without secondary optics. Chip on Board LEDs are generally more expensive than other packages and will usually require additional protection for the silicone lens. Higher powered LEDs used in COB technology will normally require additional heat sinking so it is important to ensure the complete modular system is designed suitably. 39 05 LED Technology LED packages Examples of the different LED packages in signage products 5mm diodes on flexible strip for contour mounting SMDs potted in clear resin Superflux LEDs potted in silicone COB LEDs with prism lenses 40 Optical Lens Technology In the space of just a few short years LED technology has improved to such an extent that it has overtaken other traditional methods such as Cold Cathode and Fluorescent lamps and is now rmly established as the sign- makers rst choice of illumination product. Leading manufacturers have continually developed and improved the product by achieving increasingly more light out of fewer Watts without compromising the life expectancy the industry has come to expect. Manufacturers have now reached the level whereby the benet of any improvement in diode performance is nominal. Therefore the next logical step was the introduction of optical lens technology. This innovation helps to make maximum use of the available light to suit a particular signage application. The pairing of specially designed optics with modern high light output diodes has seen a transformation in the way sign-makers use LEDs to illuminate their signs. Although there are still systems on the market which use basic exposed SMD packages these are rapidly looking somewhat antiquated. There are further advantages to designing a module with a lens as it also protects the diode from moisture humidity corrosion and physical damage. Moisture ingress is particularly harmful to LEDs as it rapidly degrades the phosphor coating on the diode itself resulting in substantial premature lumen degradation along with noticeable colour shift. White face illuminated letter signs are particularly prone to this effect. It should also be noted that not all clear acrylicpolycarbonate covers act as optics and may just be for protection. There are many different forms that the optics can take and you should consult your supplier on the best for any particular application. However the following notes give some basic ideas on what is a very complex and technical area of module design. Key to understanding this area is an understanding of polar diagrams. These are a graphic representation of the 41 05 LED Technology Optical Lens Technology light output from a point source. They are not easy to interpret. Let us look at some examples. Lambertian This is the simplest dispersion pattern from LEDs. The same amount of light is dispersed in every direction above the plane of the module and the cosine law applies. Although this could be viewed as older simpler technology it does have advantages in deep letter or box signs and the lack of lens gives slightly better efficacy. More sophisticated near Lambertian patterns are available giving slightly wider angles of dispersion. Lambertian dispersal pattern 42 05 LED Technology Optical Lens Technology Batwing This more sophisticated optic design has many variants usually associated with intellectual property issues for each manufacturer. Fundamentally more light is directed each side of the normal to spread the light more widely leading to more even illumination of the front face and the ability to space modules wider but maintaining this key evenness. Obviously this has more relevance in shallow letters or boxes. Substantial savings in capital cost based on wider module spacing can be achieved. Modules are now being developed that typically involve three lensed diodes with the centre lens creating a different light pattern to the two outer lenses. The result of this combination of lenses is a module which provides excellent uniformity and brightness even at return depths as shallow as 35mm. Batwing dispersal pattern 43 LEDs in signs For some years now Light Emitting Diodes have been used in the illumination of channel-lit built-up letters for both face and halo illumination. Continuing product improvements in light output energy consumption and unit cost has resulted in LEDs replacing almost completely the original Cold Cathode Neon product. Modular LED systems are now available in high brightness White in a range of colour warmths generally ranging from 3200k up to 7500k as well as the standard Red Blue Green and Amber Yellow colour range. Certain specialist colours can be manufactured to match a specific corporate identity although LED manufacturers will usually require commitments to large production batches. RGB Red Green Blue colour changing LEDs can effectively mix any colour in the visible spectrum. With a greater emphasis nowadays on optical lens technologies LEDs can be used at much wider module spacings reducing the quantity of product required and letters can be fabricated at shallower return depths without the fear of diode spotting. LEDs by their nature consume far less energy than traditional means of lighting such as Hot Cathode Fluorescent lamps and as the light output to cost ratio improved applications such as back lighting large-format flexible vinyl faced signs became a viable option. Higher initial installation costs can quickly be recouped with savings in electricity and maintenance and the ever reducing initial capital cost of wider spaced modern high light output LED modules with good optics make the decision to change to LED illumination a No brainer. A good quality LED system if correctly installed can provide bright eye catching signage that will remain virtually maintenance free for years to come. 44 05 LED Technology LEDs in signs LEDs are used in a diverse range of sign applications 45 06 Power Supplies The very nature of how LEDs operate dictate that they cannot be connected directly to a mains supply therefore it is necessary to provide a control device within the LED system which is usually referred to as an LED Driver. Whilst an LED Driver may appear to be just an innocuous box of electronics it is essential for correct operation of the LEDs and the inherent reliability of the complete system. Therefore it is just as important to use a quality LED Driver as it is to use a quality LED product To try and understand more about LED Drivers and why they are so important it is necessary to understand a little about electricity and the units used to measure performance. This chapter provides some basic background on the basics of electricity as well as more detailed information about LED Drivers. 46 Basics of Electricity Ohms Law Electricity is one of historys greatest discoveries and it truly does power the world we live in today. The basic properties of electricity are governed by Ohms Law where The current flowing in a conductor is directly proportional to the applied voltage V and inversely proportional to its resistance R V IxR V Voltage measured in Volts V I Current measured in Amps A and R Resistance measured in Ohms If we look at it based on a water flow system Figure 13 below then the pump voltage source provides the electromotive force Voltage V to push the water current I through the restriction in the pipe diameter resistance R and the resultant pressure difference across the restriction is the voltage drop Volts V Figure 13 Flow in a circuit Therefore if the diameter of the pipe gets smaller the resistance to the flow of water will increase. To look at this in electrical terms If the original circuit has a voltage force of 230V and a resistance diameter of pipe of 100 Pump voltage source Output pressue e.m.f. Pressure difference p.d. Restriction resistance Pipe wire Flow current 47 06 Power Supplies Basics of Electricity Ohms Law V I x R 230 I x 100 therefore the flow of water I I V R I 230100 2.3A If we then reduce the diameter of the pipe resistance increases to say 200 but the pump provides the same force as before. V I x R 230 I x 200 therefore I V R I 230200 1.15A So in this case the rate of flow of the water is halved Figure 14 Ohms Law - another way of looking at it 48 06 Power Supplies Basics of Electricity Ohms Law Using a force to push electrons around a circuit over time results in energy being expended which is referred to as Power and Power is measured in Watts W. The relationship of Power to Voltage V and Current I is determined by the following formula P V x I In the previous example we had a voltage of 230V and a current of 1.15A therefore the power consumed by the circuit would be P 230 x 1.15 P 264.5W The above example assumes a completely linear relationship between voltage and current when a circuit contains only a resistive element the sinusoidal waveforms of voltage and current are said to be in phase with one another. Power that is a result of a purely resistive load is known as true power and is the most desirable outcome of an electrical system. Electronic circuits are rarely purely resistive as they are generally made up of a number of different components as is the case with LED Drivers which result in what is known as reactive power this happens when the components cause the current in the circuit to either lead capacitors or lag Inductors the supply voltage so they are now out of phase with each other. Essentially reactive power is undesirable as it does not do any work in the system you could call it the lazy brother to true power. Why is reactive power so important This is because all practical electrical applications will contain a combination of resistive capacitive and inductive elements. Therefore any practical AC circuit or system will have a combination of both true and reactive power which will vary the phase angle between voltage and current. The desired outcome is to maximise true power while limiting reactive power. Taking both into account the end result 49 06 Power Supplies Basics of Electricity Ohms Law of a tug of war battle between true and reactive power is called complex power. This is measured in volt-amps VA The combination of true and reactive powers taking into account the phase angle by which the current lags or leads the supply voltage is called apparent power. The cosine of the phase angle is known as the Power Factor PF. This can be explained further using Phase Diagrams- Figure 15 Unity Power Factor In Figure 15 above we see that the current I is in phase with the voltage V this means that all the power required to operate the system is true power and has a Power Factor of 1 or sometimes it is called Unity Power Factor Figure 16 Current lags supply voltage In Figure 16 we can see that the current I lags the supply voltage V by a phase angle . This means that the resultant power required to operate the system is apparent power and is caused by an inductive reactance. The Power Factor in this circuit will be the cosine of which will be less than 1. PF1 V l V l 50 06 Power Supplies Basics of Electricity Ohms Law Figure 17 Worked example In Figure 17 we are looking at a worked example If we just used PVI to determine the power consumed we would get P230X0.5 115W. However to work out the apparent power we have to take into consideration the lagging phase angle . The cosine of 35 is the Power Factor PF and in this case PF 0.82. Therefore the apparent power in the system is 1150.82 140VA of which 25VA is not doing any work reactive power. So how do we correct this and reduce the reactive power Fig 18 below shows that we introduce a capacitive reactance to the circuit which leads the supply voltage by 90. Figure 18 With capacative reactance 0.5A 230V 35 V lc 51 06 Power Supplies Basics of Electricity Ohms Law Fig 19 below shows how this is used to bring the current and voltage closer together. Figure 19 Current and voltage closer together The resultant current Im is a phasor addition of the lagging and leading current it is smaller in size than IL and now lags the supply voltage by a smaller angle. So lets say the angle has reduced to 15 the power factor has improved to 0.97 cos and the apparent power is reduced. Therefore if this was applied to our working example the apparent power would now be 1150.97 118.5VA so now we have only 3.5VA not doing any work reactive power Why is this so important A lower power factor circuit will have a higher apparent power and higher losses for the same amount of true power. For two systems transmitting the same amount of true power the system with the lower power factor will have higher circulating currents due to energy that returns to the source from energy storage in the load. These higher currents produce higher losses and reduce overall transmission efficiency. If we apply this to a practical example concerning a LED Driver a driver V lc 52 06 Power Supplies Basics of Electricity Ohms Law with a low lagging Power Factor of say 0.5 would result in greater efficiency losses in the mains supply than a LED Driver with a Power Factor of say 0.95. It effectively means that higher currents will circulate in the wiring and more power will need to be generated from the grid to supply the load. In summary an LED Driver with a Power Factor of closer to 1 is generally more desirable therefore it is good practise to specify a LED Driver with a PF 0.95 over one with only a PF 0.50. 53 Introduction to LED Drivers The typical LED driver pcb has two large electrolytic capacitors which are usually the life limiting factor in any electronic device. Use of high quality reliable components is essential in any driver design and to get the best lifetime you would over specify the critical components so that in normal operation they will only be used at say 50 of their rated capacity. Why are some LED Drivers potted The potting compound is a kind of resin and can be made up of several different materials. The potting compound mainly has two main functions 1 Dissipating the heat generated by the components. 2 Protecting the components from the environment IP. A good resin is not too hard as it could crack causing damage to the pcb and components. Cracks would also allow moisture to enter the circuit. On the other hand the resin should not be too soft either so that vibrating components dont weaken the resin and make openings in the material. A good potting compound can be 25x better at heat dissipation than air Efficiency Efciency is the term used to describe the ability of the Power Supply to convert the input supply into the required output supply whilst consuming as little energy as possible. Efciency is expressed as a Percentage. Higher Percentage greater efciency Efficiency vs Power Loss an example see Figure 20 overleaf For a 150W supply 95 efficiency 7.9W loss 85 efficiency 28.5W loss 54 06 Power Supplies Introduction to LED Drivers So a difference in efficiency of just 10 creates 3.6 times the power loss All of the power loss is dissipated in the driver as heat Figure 20 Efficiency vs Power Loss Efficiency vs Reliability an example see figure 21 opposite All other factors being the same the heat dissipated to power loss has a significant impact on reliability expressed as MTBF Mean Time Between Failures. In this example an 84 efficient driver has about half the MTBF of a 94 efficient driver. Summary the Triple Impact of Efficiency Lower energy costs result in direct operating savings 55 06 Power Supplies Introduction to LED Drivers Lower component temperatures produce higher reliability and longer life The difference is bigger than you may think Advice for Comparing Various Drivers Always measure case temperature in application Two drivers can both have a life of 50000 hours at a Tcase of 60o C and yet yield very different lifespan results in application due to efficiency and thermal design A difference of 10o C can yield a 2x difference in product life Figure 21 Efficiency vs Reliability 56 06 Power Supplies Introduction to LED Drivers Power Factor A decimal number that describes the phase angle shift between the voltage and current waveforms of a circuit. The further out of phase the lower the power factor. Therefore more correction is needed to bring the waveforms together. Normal Power Factor 0.5 High Power Factor 0.9 Perfect 1.0 57 Types of LED Drivers Constant Current Drivers The term Constant Current Driver describes an LED driver whose output current remains at a constant level and whose output voltage is dependent upon the connected load. Imagine that the battery is the LED Driver and the lamps are LEDs the driver is wired in series with the LEDs and means that the current owing in each LED is the same Figure 22. The advantage of this type of circuit is that no other form of current control is required as the driver limits the current in the circuit which is necessary for LEDs and therefore the lighting part of the circuit is less expensive to produce. Coincidentally the cost of the driver can also be lower than a constant voltage device. Furthermore the much lower component count for the total system at least one less component per module can lead to greater reliability for constant current systems over constant voltage all other things such as component quality being equal. The disadvantage of such a circuit is that if one LED goes out open circuit the rest of the LEDs connected will also go out as the circuit has been broken. However as the sophistication of LED technology continues to increase driverLED module systems are now appearing that overcome this disadvantage usually involving a third wire. Constant current circuits are mostly used for operating LEDs used in general lighting xtures but also have advantages in linear LED installations in signs. Figure 22 Constant Current Circuit 58 06 Power Supplies Types of LED Drivers Constant Voltage Drivers The term Constant Voltage Driver describes an LED driver whose output current will vary to allow the output voltage to remain at a constant level. Again imagine that the battery is the LED Driver and the lamps are the LEDs the driver is wired in parallel with the LEDs and means that each of the LEDs receives the same voltage Figure 23. As LEDs by their very nature require a constant current to operate satisfactorily and this is not provided by a constant voltage driver it is necessary to place some form of current control in-between the driver and the LEDs therefore the lighting part of the circuit becomes more expensive to produce. This is clearly a disadvantage. The advantages of a constant voltage LED driver easily outweigh the disadvantage mentioned when it comes to LED modules designed for signage applications. If one LED goes out open circuit the rest of the LEDs in the circuit will continue to operate so the part of the sign operated by that particular circuit will continue to be illuminated. Generally speaking you can run more LEDs from a constant voltage driver over longer lengths of cable and you do not have to run a cable from the furthest LED in series back to the power supply as you would have to do in a constant current series circuit. Figure 23 Constant Voltage Circuit 59 06 Power Supplies Types of LED Drivers Summary When making a choice of Driver for your LED illuminated signage system you should consider the following. Is the driver from a reputable manufacturer Does it meet all current European Norms e.g. EMC RFI SELV LV Directive Is it the right driver for my application Do I need constant current or constant voltage Do I need a potted driver for use in a sign outdoors Can it power the amount of LEDs I want to run What is the efficiency Higher percentage is better What is its ambient temperature rating Ta Higher Ta rating is better do not use Tc MAX as a measure What is the power factor Closer to unity power factor of 1 is better Finally remember that just like LED systems no two LED Drivers from two different manufacturers will ever be exactly the same. Utilising a low cost unit is likely to be a false economy as replacing it in the event of poor performance or failure will be significantly more costly than the initial price differential. 60 Continuing developments in LED brightness has led to the need to introduce dimming controls. Local authority advertising consent can sometimes rest on the ability to be able to reduce the light output to a level that does not have a detrimental effect upon the visual amenity. European directives and local regulations concerning the environment are having greater impact on the recommendations and legislation that govern light pollution. Certainly illuminated signs will continue to come under ever increasing control and this is covered in another chapter of this book. During daylight hours there may not necessarily be a need to decrease the luminance of an illuminated sign however during the hours of darkness regulations may stipulate that the sign be dimmed to decrease the luminance according to where the sign is located and the amount of glare or light pollution that may be produced. For many illuminated signs especially those installed externally there may be times when illumination is not necessary for example outside of normal trading times in a retail environment. The use of LEDs over more conventional technology invariably saves energy. That does not mean that more cannot be done to reduce energy consumption even further. Controlled dimming can play its part in reducing energy consumption even with the most efficient systems simply by switching off the circuit when not needed or dimming it where circumstances allow. Basic Control The most basic form of lighting control is a simple manual switch fitted on the mains side of the circuit. See Figure 24. This is not the most reliable way of making sure energy is being saved as it relies on human intervention. 07 Controls Dimming 61 07 Controls Dimming Mains Supply LED Driver LED Modules Manual Switch Figure 24 Schematic wiring diagram for basic lighting control 12 Volt DC systems can be dimmed on the secondary side so long as the system is supplied with a dimmable driver. A standard 0-10 Volt potentiometer can be added to the circuit on the secondary side to provide a manual dimming facility from 100 brightness down to approximately 20. The unit can be set to the required level and then stored inside the lightbox so long as it is in a waterproof enclosure or sited remotely from the sign allowing the client to adjust the light level as the need arises. One controller can be linked to multiple drivers allowing all the LEDs in the sign to be dimmed in conjunction. Automated Control The addition of a relatively simple photocell to the mains side of a circuit provides an excellent method of lighting control and consequent energy reduction. Figure 25 explains the operation. 62 07 Controls Dimming Figure 25 Schematic wiring diagram for basic lighting control One area of concern with this type of installation is if the photocell operation turns the supply to the driver off and on too rapidly ie at intervals of less than 700 milliseconds This can occur with some sensors just at the point of where the light starts to fade but can still vary for a period of time until darkness sets in. This rapid pulsating effect can register as a fault with the LED driver and result in OnOff flashing which continues until the power supply is switched off completely whereupon the fault mode within the driver re-sets itself. Care should be taken to ensure that the chosen photocell has a facility within it that limits the rate of switching. Off the shelf Dimming control devices are now becoming more sophisticated and when used in conjunction with light sensors or photocells can provide controlled dimming that adjusts to the ambient surroundings. Simple modular units that incorporate dimmer photocell and timer in conjunction with a dimmable driver can be set to switch on at a certain time 1. During daylight the relay contact is open and the LEDs are off 2. At dusk the photocell switches the coil of the relay closing the relay contact and switching the LEDs on 3. At dawn the photocell removed the supply from the relay contact the relay opens and the LEDs turn off again Mains Supply LED Driver LED Modules Light Photocell with Built-in Relay 63 07 Controls Dimming dim up or down as the surrounding light conditions dictate via the photocell and then switch off completely at dawn. This process is automatic and requires no further manual input throughout the life of the sign As an added benefit controlled dimming can help to reduce energy consumption by approx 20-30 compared to normal use depending upon the extent that the signed is dimmed or switched on and off over a 24 hour period. Modular unit incorporating dimmer photocell and timer 64 How LEDs are dimmed and their effects With LED systems dimming is fairly straightforward and it does not affect the useful lifetime of the LEDs and indeed in most cases lifetime will increase as the LEDs are effectively running cooler. When dimmed LED circuits also use less energy. Many LED drivers are available that can dim LEDs and the most popular method of achieving dimming is with PWM Pulse Width Modulation. Basically instead of the LEDs receiving a steady fixed DC Voltage they are switched on and off very quickly which results in them only being on for only part of the time. You would be forgiven for thinking that if the LEDs are switched on and off any person would be able to see flickering however due to the speed at which they are switched onoff the human eye cannot perceive the difference between on and off. The observer is then tricked into believing that the LED has reduced in brightness although the voltage has not been decreased this is because what the human brain registers through the eye is only part of the switch on and switch off cycle. See Figures 26 and 27. Figure 26 A constant steady voltage in this instance the LEDs would be on at 100 brightness. DC Voltage Constant Voltage Time in milliseconds 65 07 Controls Dimming How LEDs are dimmed and their effects Figure 27 The same voltage but it is only on for half of the time this is called a 50 duty cycle and the LEDs would appear to be 50 of their normal brightness. If we were to reduce the duty cycle so that the LEDs were only on 10 of the time this would result in the LEDs to appear to be only 10 of their normal brightness and so on. DC Voltage Time in milliseconds 50 Duty Cycle 66 Control Signals The process of how LEDs are dimmed has been covered in the preceding chapter however there has to be a signal to the dimmable LED driver to tell it what dimming level i.e. duty cycle is required by the user. There are many different protocols that are used to send signals to a LED dimmable driver and the types which we are going to look at are the most popular in use today for signage applications. Mains Dimming Phase Dimming Usually this is used to directly dim purely resistive loads such as filament lamps but there are LED dimmable power supplies available that will accept this as a control signal input and in turn dim the LEDs using PWM on the output. This way of dimming is useful if there are only the mains input cables available to connect the driver. Analogue Dimming This method uses a pair of low voltage cables to connect an electronic potentiometer to the dimmable driver and usually a 0-10V signal is transmitted along these cables to tell the driver at what level the LEDs should be dimmed. OV would mean that the LEDs are on at 100 i.e. no signal and 10V would result in the LEDs being off. Somewhere in between the two lets say 5V would roughly result in the LEDs being dimmed to 50. There are some limitations to this method of dimming such as length of signal control cables voltage drop and the necessity to keep these cables away from running too close and in parallel to mains cables voltages may be induced in the low voltage cables causing dimming instability Digital Dimming DALI DMX etc. DALI stands for Digital Addressable Lighting Interface DMX stands for Digital MultipleXing 67 07 Controls Dimming Control Signals Both of these are popular lighting protocols for use in dimming applications. They use binary codes contained within a carrier voltage which are interpreted by the dimmable LED driver as a dimming level command. These methods are mainly used in stage and studio lighting DMX and general lighting DALI but are useful in applications where you may want to give connected drivers their own unique address and then only send commands to a single driver or a group of drivers whilst the other drivers connected to the same cables are ignored. Having mentioned the above methods there are many more available if so desired. Internet and wireless based controls are becoming increasingly popular and these can be readily incorporated into signage applications through the use of dedicated converters or dimmable LED Drivers which are already enabled to accept signals from such devices. 68 08 Performance Reliability LEDs are inherently more reliable than the technologies they are replacing and not just by a few percentage points. A correctly designed and installed LED can outlast traditional incandescent bulbs by many thousands of hours. This fact alone has been significant in the rapid uptake of LEDs in all kinds of applications and when considered together with the advantages of lower energy consumption and greatly improved light output of modern LEDS its no wonder this technology has all but replaced traditional illumination sources. In signage applications a key consideration is the frequency of device replacement as maintenance is a major element within the lifecycle cost of an installation. Whilst offering greatly extended lifespan LEDs are subject to failures and performance degradation over time which can be caused by a variety of factors. This chapter outlines the factors affecting LED performance as well as highlighting the potential problems caused by degradation - and how to avoid these. 69 Thermal Management High power light emitting diodes can disperse as much as 70 of their energy in the form of heat. If there is no facility in place to disperse this heat it will cause the LED junction temperature to increase which will in turn severely limit efficiency and rapidly increase lumen depreciation. Inefficient thermal management can also lead to phosphor degradation and subsequent colour shift in white LEDs In general terms heat can be transferred in three ways Conduction Convection Radiation In many modular LED systems heat is generated by the electrical energy that was not converted to useful light. This heat is then conducted away from the diode via a long path from junction to board and board to the heat sink and then to the atmosphere. System efficiency can be optimized by incorporating methods to reduce thermal resistance along the path of dissipation. Thermal resistance will vary depending on the type of material selected. Common materials are epoxy thermal grease pressure sensitive adhesive and solder. Thermal conductivity whereby heat spontaneously flows from a body at a higher temperature to a body at a lower temperature until a state of equilibrium is reached is the most efficient method of heat dissipation in LEDs. Diodes that are encapsulated in a transparent resin are poor thermal conductors as nearly all heat produced is conducted through the back side of the chip and unless the system incorporates a substantial heat sink there is little opportunity for the heat to be drawn away from the diode. The thermal conductivity of the material that the heat sink is made from directly 70 08 Performance Reliability Thermal Management affects the dissipation efficiency through conduction. Normally this is aluminium but copper is used in certain applications. Graphite can also be used as an effective heat sink but is cost prohibitive. Thermal transfer takes place at the surface of the heat sink. Therefore heat sinks should be designed to have a large surface area. This can be achieved by incorporating a number of fins into the design or by increasing the size of the heat sink itself. Thermal radiation of heat sinks is affected by surface finish especially at higher temperatures. A painted surface will have a greater capacity to emit heat than an unpainted surface. The effect is more noticeable with flat heat sinks where a high proportion of the heat is dissipated by radiation. A flat contact area allows the use of a thinner layer of thermal compound which will help to reduce thermal resistance between the heat sink and LED source. Convection or more precisely forced convection occurs when a fluid or gas is forced to flow over the surface of a heated object by an external source such as a fan creating an artificially induced convection current. Therefore in areas where there is a high ambient temperature such as for example a light box in a high temperature climate or environment the installation of a small electric fan can help to draw heat away from the LED. 71 Lumen Depreciation As with most light sources LED output degrades over time. This is known as lumen depreciation. This rate of this degradation is due to a combination of factors Thermal management LED modules require adequate heat sinks to allow the heat to dissipate from them. Without this the temperature of the device will rise leading to lower light output. Continuous high temperature operation will result in permanent reduction in light output. Drive current Some LED products are designed to increase the driver current to compensate for lumen depreciation. This will in fact speed up the process. Environmental conditions Ambient temperature moisture and pollutants can affect the diode which needs adequate protection from these factors. Operating efficiency and the duration of continuous operation. If used in an environment with optimal operating temperatures and good ventilation LEDs can have life spans far exceeding conventional light sources. An LEDs lifetime is typically considered to be the hours of operation before the output of the LED reaches 70 of its original value. This lifetime is known as L70. After this point the light level is generally considered to be unacceptable for most signage applications. 72 08 Performance Reliability Lumen Depreciation As the average LED life is 50 000 hours testing for this amount of time would be futile as products would be obsolete due to the constantly improving technology. Due to this the LM80 See page 129 test has been introduced which is a 6000 hour test measuring the lumen depreciation of an LED. The results of this test can be shown in a graph which can then be used to make a prediction on the future lumen depreciation of the LED. Figure 28 Chart showing lumen depreciation over time Data Extrapolation - Long Term Lumen Maintenance LF 105.0 100.0 95.0 90.0 85.0 80.0 75.0 70.0 65.0 1000 10000 Time hours 100000 73 Colour Shift For any given CCT value there is a wide range of chromaticity values above and below the black body locus that all have the same CCT. In practice this means that an LED with a CCT of 4000K that you may think would appear as a standard white colour can actually appear with a green tint a purple tint or anything in between. Over the course of an LEDs lifetime a diode which may at first have appeared as a standard white can shift in colour dramatically. The main reason for this is damage by pollutants in the air such as those from vehicle exhausts. These can degrade the phosphor in the diode. This in turn starts to remove the white colour to the diode and reveal the true blue or green colour of the LED chip. This may only make a slight difference in some cases not visible to the eye. In other instances however the shift can be so great as to make the sign look completely different and therefore lead to the LED needing to be replaced. Whilst all LEDs receive some form of protection from environmental pollutants by being housed inside their sign this does not provide total protection. Also in a set of built up letters each letter can be sealed differently resulting in varying degrees of damage to each diode. To help prevent LEDs from being affected by the environment in this way some manufacturers now design LED modules with a protective cover and or lens over each diode which give a much greater level of protection than a diode with no cover or lens. 74 LED Binning LEDs are semiconductor devices and as such the performance between diodes is inherently variable according to the quality of the natural raw material from which the LED is made. To ensure that LEDs are grouped based on their performance and to therefore improve their consistency manufacturers sort the LED into bins according to different parameters. These parameters include lumen output colour temperature and forward voltage. Once sorted into bins manufacturers can utilise different bins for their needs. The most important binning characteristics are colour wavelength and lumen output as these attributes are fundamental in the performance of the LED. Binning for lumen output is fairly straightforward. The LEDs are individually measured and then sorted by their output into set ranges. The LED can then easily be selected according to the manufacturers requirements. Colour temperature bins are measured in Correlated Colour Temperature CCT this is a relative measure of the colour of light produced by white LEDs. This is particularly important with LED as it differentiates between the different shades of white a higher CCT means a cooler white and lower CCT corresponds to a warmer white. Once the CCT is determined the LED is put into bins accordingly and can be selected for purpose by the manufacturer. With a tighter bin range the LEDs within it are more consistent in their characteristics. This process involves a higher cost to the manufacturer. In 2008 The American National Standards Institute known as ANSI developed a procedure in order to standardise the description of tints in LEDs. To do this they set up 8 points with coordinates based on CCT. These are called quadrangles See Figure 29. Each of these quadrangles is then divided into quadrants See Figure 30 and bins can be selected from these according to colour accuracy. 75 08 Performance Reliability LED Binning Figure 29 Chart showing basic ANSI quadrangles with centres marked with blue dots Figure 30 Chart showing quadrants within ANSI quadrangles. In this instance sub bins are chosen from quadrants within 3 McAdam ellipse steps 76 08 Performance Reliability LED Binning Saturated Colours Coloured LEDs are not binned in the same way as white diodes. This is because a saturated colour is determined by its location around the edges of the chromaticity diagram which is measured in nanometres nm. Generally speaking a red diode would be taken from the position of around 625nm this value will be specified on a manufacturers technical data sheet. Some manufacturers however may want to select their diodes from a different nanometre reading this is generally only the case if an end user has a large requirement for a different colour of LED. Figure 31 Chart showing where saturated colours sit on the chromaticity diagram 77 09 Sign Design The fundamental concept behind signs and sign based advertising is that the message should be noticed read and understood therefore the first considerations to be made in the design of any sign are visibility and legibility. Visibility The visibility of a sign depends on a number of factors including- Location Surroundings Viewing angle Whether it is lit or not at night If a sign has trees growing between it and the observer it will not be very visible. If it is one small sign amongst many it will not be readily visible. If it is parallel to the road it will not be as readily visible to passing motorists as one placed at right angles to and adjacent to the road. At night an unilluminated sign will only be visible if caught in headlights or other light source carried by the observer. Taking the latter point a little further the inverse square law applies so the light level received by the observer decreases by the square of the distance from the sign. E.g. An observer at 100 metres receives one sixteenth of the light of an observer at 25 metres. 100254 4416. The sign therefore needs to emit or reflect if externally illuminated enough light for the eye to see at the required distance. Note- This is for the sign to be visible not necessarily legible. 78 09 Sign Design Legibility We will assume that we are considering reading some text rather than recognising a logo as the factors are different. The legibility of a series of letters or words depends on many factors including- Letter size Letter shapefont Letter spacing Letter and background colourscontrast Background to surroundings colourscontrast Light output Viewing time Many of these are outside of our control e.g. viewing time but still need to be taken into account. However lets look at some of the factors that can be under our control. Letter height and shape Often the letter shape is dictated by the corporate design and it is then not under our control. In other cases then there is no doubt that a vertical sans serif font with a stroke width of 15 to 17 of letter height is the most legible font. Any variation from this will reduce legibility. So from what distance is this style legible If we assume a simple style like Helvetica Medium using black letters on a white ground then it has been established that the required letter height is given by- 79 09 Sign Design Minimum Letter Height Distance from observer. 430 X K where K is a factor related to the letter of the alphabet in question. Most letters have a factor between 0.9 and 1.1. Given the variabilities we will discuss later it is best to use 0.9 unless otherwise dictated by the exceptions. The exceptions are- B 0.85 I 1.4 J and L 1.2 M and W 1.13 T 1.15 You should use the factor for the lowest rated letter. e.g. For the word LETTER the lowest would be the default 0.9. For the word BETTER the lowest is 0.85 from the B. Using this formula for internal mall based shop signs would not be sensible since the shop fascia height is often more than the minimum letter height suggested by the formula. However the formula is applicable to exterior signage and wayfinding. For indoor wayfinding the figures need to be raised by about 20 to allow for the generally smaller sign area and the lighting. The factor 430 in the above is an empirical factor based on the very legible Helvetica Medium font. If other fonts are used then the factor changes. The following gives some guidance. Unfortunately the situation is so complex that complete information is not available. However for a font with a stroke width of 22 to 26 of height the factor is 340 and 30 stroke width the 80 09 Sign Design factor is 220. For fonts with serifs the factor is of the order of 300. Letter spacing It has been established that the human eye can discern horizontal spaces which subtend about 1 minute of 1 degree at the eye. This is equivalent to about 150 mm at a distance of 500 metres or 30 mm at a distance of 100 metres. However in illuminated signs this spacing would be too small owing to the effect of halation. Colour contrast Empirical tests have shown that black letters on a white or yellow background are the most legible. This is closely followed by the reverse of white or yellow letters on a black ground. It has been suggested that the letter height for the latter need to be 5 greater to maintain legibility. The remaining colour combinations need about 10 more height except the worst two red letters on a white ground and white letters on a red ground which need a 15 uplift. With regard to a signs visibility against the surroundings it has been suggested that a black sign needs to have about twice the area as a yellow or white sign to be conspicuous. Speed of recognition It is reported that average people read an average word under average conditions in 0.7 seconds. It has also been established that a longer time is required if the sign is not in the viewers first language or if they suffer from dyslexia. This recognition time is shorter when the observer does not need to read but just recognise a logo or brand. For street advertising or road signs the high speed of traffic distance set back from the road and viewing 81 09 Sign Design angle all lengthen the recognition time and need increased letter height for increased conspicuity. This is one reason why road signs tend to be icon rather than word based. Sign Luminance As noted earlier a minimum sign luminance is necessary for the sign to be visible. As luminance increases the sign becomes more legible and effective up to a certain point depending on circumstances. If luminance is increased further a sign can become too bright lose legibility due to halation and have a negative affect on amenity and cause nuisance or hazards due to glare. At night the eye adapts to average brightness in the field of view and a sign that looks fine in daylight may cause glare and nuisance at night. Note that local and national planning regulations limit sign luminance or in some countries illuminance of surroundings in much of Europe. 82 Material Selection Performance comparison charts for Acrylic sheet on the following pages have been made using the following apparatus 1 Custom made demountable cubic replica sign box 150 mm on a side with open front face. 2 Specbos 1201M Spectroradiometer tripod mounted. 3 Custom made demountable dark room to enclose 1 and 2 above. 4 Compaq Presario V6000 laptop computer running JetLimes software Version 4.5.3. 5 LEDs and LED control gear as applicable. Test method In each case a single LED module is placed centrally in the simulated sign case and aligned in the field of view of the spectroradiometer. The front face required is placed on the simulated sign case and the whole enclosed in the custom dark room. The drive gear is powered up and after stabilisation time a measurement is made using the laptop and JetLimes software. A series of measurements can be saved as an Excel file. Discussion The results are valid for AB comparisons of LED modules or acrylic types and any permutation and combination thereof. The results will reflect the relative performance of LED andor front face material but the figures for luminance and efficacy may not be reproduced in a project as both are dependent on the exact geometry involved. If final luminance figures are required then the actual sign should be measured. For white front faces this may be carried out with the simple device available from Vink Lighting 83 09 Sign Design Material Selection Solutions. For coloured front faces more sophisticated equipment such as that used here would be required. The following tables demonstrate the results that can be obtained and the types of comparisons possible to aid in selection of one LED over another andor one acrylic over another. They clearly demonstrate the advantages of selecting the correct colour temperature for optimum efficacy in cdm2 per Watt and the advantages in efficacy available with the TruLed type of acrylic. The examples shown are limited to white acrylic but data can be obtained for almost any LEDacrylic combination. Disclaimer Vink Lighting Solutions and Mike Hall Technical Services cannot be held responsible for any consequences based on action or inaction resulting from this report. 84 09 Sign Design Material SelectionAcrylicColourRef.050DescriptionSTANDARDWHITEColourUnlitWHITE Numberofmodules1 Areailluminated150mmX150mm ModulePlacementCentral ProductDescriptionGETetraMiniMAXGen3GETetraMAXGen3GETetraMAXHOGen3 ProductCodeGEWHMMTS8GEWHMXTS6GEWHMHTS6 WattspermoduleLit.0.460.580.86 LEDColourTemperatureLit.7100K5000K4100K3200K7100K5000K4100K3200K7100K5000K4100K3200K Luminancecdsqm180199175158206237198171324359303295 Efficacycdm2 Watt392432381344448514430371703780659640 CorrelatedColourTemp.CCTK652048973897285069134749384430126874495538852944 DominantWavelengthDWlnm490.3569.0578.7583.2486.4572.7579.2584.4485.1570.7579.3582.6 ColourPurityPE7.416.830.658.19.916. ChromaticityCoordinates x0.31200.35080.38540.44960.30650.35420.38740.42970.30750.34770.38510.4432 y0.33100.37170.38280.41040.32250.36580.38260.39160.32060.36010.38020.4099 u0.19660.20760.22600.25600.19590.21200.22730.25130.19740.20990.22680.2521 v0.46930.49500.50500.52570.46390.49270.50520.51530.46300.48910.50380.5246 ColourRenderingIndex ReferenceIlluminant Daylight 5000- 7000K Planckian radiator Planckian radiator Planckian radiator Daylight 5000- 7000K Planckian radiator Planckian radiator Planckian radiator Daylight 5000- 7000K Planckian radiator Planckian radiator Planckian radiator Ra75.4966.7781.7581.2476.7567.9182.2483.4475.0667.9781.9680.99 FiguresinthisrowapplytoaparticulartestgeometryonlyandareprovidedtofacilitateABcomparisonsofLEDsoracrylics. Othergeometryorsigndesignmayresultindifferentfigures. 85 09 Sign Design Material Selection AcrylicColourRef.A003DescriptionACRYCASTA003ColourUnlitWHITE Numberofmodules1 Areailluminated150mmX150mm ModulePlacementCentral ProductDescriptionGETetraMiniMAXGen3GETetraMAXGen3GETetraMAXHOGen3 ProductCodeGEWHMMTS8GEWHMXTS6GEWHMHTS6 WattspermoduleLit.0.460.580.86 LEDColourTemperatureLit.7100K5000K4100K3200K7100K5000K4100K3200K7100K5000K4100K3200K Luminancecdsqm381420353331364439372315324359303295 Efficacycdm2 Watt827914768720792954809685703780659640 CorrelatedColourTemp.CCTK621647253788278270754759384130086874495538852944 DominantWavelengthDWlnm493.8570.8579.4583.7485.7572.8579.3584.5485.1570.7579.3582.6 ColourPurityPE5.220.132.459.510.815.730.946.39.812.429.756.1 ChromaticityCoordinates x0.31730.35660.39010.45420.30430.35380.38730.42970.30750.34770.38510.4432 y0.33600.37670.38430.41040.32010.36510.38200.39090.32060.36010.38020.4099 u0.19840.20960.22840.25890.19530.21200.22750.25160.19740.20990.22680.2521 v0.47270.49800.50630.52640.46230.49240.50490.51500.46300.48910.50380.5246 ColourRenderingIndex ReferenceIlluminant Daylight 5000- 7000K Planckian radiator Planckian radiator Planckian radiator Daylight 7000K Planckian radiator Planckian radiator Planckian radiator Daylight 5000- 7000K Planckian radiator Planckian radiator Planckian radiator Ra75.5067.0082.1181.5376.9968.0882.4983.6775.0667.9781.9680.99 FiguresinthisrowapplytoaparticulartestgeometryonlyandareprovidedtofacilitateABcomparisonsofLEDsoracrylics. Othergeometryorsigndesignmayresultindifferentfigures. 86 09 Sign Design Material SelectionAcrylicColourRef.A005DescriptionACRYCASTA005ColourUnlitWHITE Numberofmodules1 Areailluminated150mmX150mm ModulePlacementCentral ProductDescriptionGETetraMiniMAXGen3GETetraMAXGen3GETetraMAXHOGen3 ProductCodeGEWHMMTS8GEWHMXTS6GEWHMHTS6 WattspermoduleLit.0.460.580.86 LEDColourTemperatureLit.7100K5000K4100K3200K7100K5000K4100K3200K7100K5000K4100K3200K Luminancecdsqm226247216197260299249214413451384370 Efficacycdm2 Watt492536470428565649542466898981834805 CorrelatedColourTemp.CCTK662849433939286670304801388130366999501439222964 DominantWavelengthDWlnm489.4568.5578.7583.2485.9572.3579.1584.3484.5570.1579.1582.5 ColourPurityPE8.115.929.457.310.615.030.245.710.511.328.955.4 ChromaticityCoordinates x0.31030.34920.38330.44780.30490.35250.38560.42800.30580.34590.38350.4416 y0.32920.37010.38100.40920.32090.36420.38140.39080.31870.35830.37940.4094 u0.19610.20720.22530.25540.19540.21150.22670.25060.19690.20940.22600.2513 v0.46810.49400.50390.52500.46280.49180.50440.51470.46170.48800.50320.5241 ColourRenderingIndex ReferenceIlluminant Daylight 5000- 7000K Planckian radiator Planckian radiator Planckian radiator Daylight 7000K Planckian radiator Planckian radiator Planckian radiator Daylight 5000- 7000K Daylight 5000- 7000K Planckian radiator Planckian radiator Ra75.6666.8981.9481.3176.8767.9582.2983.4875.1367.5381.9580.99 FiguresinthisrowapplytoaparticulartestgeometryonlyandareprovidedtofacilitateABcomparisonsofLEDsoracrylics. Othergeometryorsigndesignmayresultindifferentfigures. 87 09 Sign Design Material Selection AcrylicColourRef.WH14DescriptionTRULEDWH14ColourUnlitWHITE Numberofmodules1 Areailluminated150mmX150mm ModulePlacementCentral ProductDescriptionGETetraMiniMAXGen3GETetraMAXGen3GETetraMAXHOGen3 ProductCodeGEWHMMTS8GEWHMXTS6GEWHMHTS6 WattspermoduleLit.0.460.580.86 LEDColourTemperatureLit.7100K5000K4100K3200K7100K5000K4100K3200K7100K5000K4100K3200K Luminancecdsqm276301263238316364304258502550469451 Efficacycdm2 Watt601654573518686791661561109111961019981 CorrelatedColourTemp.CCTK676950153997289772284884394430767191509839872997 DominantWavelengthDWlnm488.5567.5578.4583.0485.3571.5578.8584.2484.0568.7578.8582.3 ColourPurityPE9.014.728.256.411.713.628.944.611.59.927.754.5 ChromaticityCoordinates x0.30810.34700.38080.44560.30230.34980.38290.42530.30330.34350.38070.4392 y0.32710.36840.37940.40870.31840.36200.37990.38970.31620.35620.37800.4087 u0.19530.20630.22430.25410.19450.21060.22540.24920.19610.20850.22480.2501 v0.46660.49290.50280.52450.46100.49030.50330.51380.45990.48670.50220.5235 ColourRenderingIndex ReferenceIlluminant Daylight 5000- 7000K Daylight 5000- 7000K Planckian radiator Planckian radiator Daylight 7000K Planckian radiator Planckian radiator Planckian radiator Daylight 7000K Daylight 5000- 7000K Planckian radiator Planckian radiator Ra75.7166.3781.9881.3276.9167.9382.3083.5375.1767.5881.9280.96 FiguresinthisrowapplytoaparticulartestgeometryonlyandareprovidedtofacilitateABcomparisonsofLEDsoracrylics. Othergeometryorsigndesignmayresultindifferentfigures. 88 09 Sign Design Material SelectionAcrylicColourRef.WH72DescriptionTRULEDWH72ColourUnlitWHITE Numberofmodules1 Areailluminated150mmX150mm ModulePlacementCentral ProductDescriptionGETetraMiniMAXGen3GETetraMAXGen3GETetraMAXHOGen3 ProductCodeGEWHMMTS8GEWHMXTS6GEWHMHTS6 WattspermoduleLit.0.460.580.86 LEDColourTemperatureLit.7100K5000K4100K3200K7100K5000K4100K3200K7100K5000K4100K3200K Luminancecdsqm198215189171228262219186362550333324 Efficacycdm2 Watt4304674123724955704764057871196723705 CorrelatedColourTemp.CCTK658449223924285869894779386630246949509838992953 DominantWavelengthDWlnm489.7568.8578.8583.3486.0572.6579.2584.4484.7568.7579.2582.5 ColourPurityPE7.816.229.657.410.415.430.546.010.29.929.555.7 ChromaticityCoordinates x0.31100.34990.38390.44830.30550.35310.38630.42880.30650.34350.38460.4424 y0.32980.37070.38100.40910.32130.36470.38170.39100.31930.35620.38010.4095 u0.19640.20740.22570.25570.19570.21180.22700.25100.19720.20850.22650.2517 v0.46850.49440.50390.52510.46310.49210.50460.51490.46210.48670.50360.5243 ColourRenderingIndex ReferenceIlluminant Daylight 5000- 7000K Planckian radiator Planckian radiator Planckian radiator Daylight 5000- 7000K Planckian radiator Planckian radiator Planckian radiator Daylight 5000- 7000K Daylight 5000- 7000K Planckian radiator Planckian radiator Ra75.7366.9482.0281.3676.9067.9582.3383.5075.1167.5881.9481.02 FiguresinthisrowapplytoaparticulartestgeometryonlyandareprovidedtofacilitateABcomparisonsofLEDsoracrylics. Othergeometryorsigndesignmayresultindifferentfigures. 89 Layout drawings and populations There is a vast array of LED modular systems available and manufacturers are adding and developing new systems almost on a daily basis. In order to ensure that the most competitive system is being offered for a particular roll-out programme or even a one-off special the discerning buyer should make sure that their LED supplier can supply detailed module for module layout drawings on the specific system being offered. Software programmers such as Aries Graphics work closely with the major LED manufacturers to ensure that their estimating systems incorporate the latest data relating to module dimensions layout parameters energy consumption and light output allowing the system distributor to supply detailed layout guides which can be used for a number of purposes including advertising consent applications installation guides inserts into technicalhealth safety manuals etc The information supplied with the drawings can also include energy consumption data and savings estimates compared to other lighting products as well as light output data and estimated luminance figures and even suggested power supply breaks. The information normally required from the sign maker to be able to make an accurate reliable estimate would be Vectorised artwork files AI PDF EPS and DXF formats usually acceptable. Letter dimensions including height stroke width return depth. Illuminating material i.e. acrylic brand and colour reference Required luminance levels candelas per sq. metre. The information supplied with these drawings helps the buyer to order just enough product for a particular project and most distributors nowadays are happy to supply a kit of parts that includes just the right amount of each product LED drivers supply wire connectors and end caps to 90 09 Sign Design Layout drawings and populations populate a particular set of letters. This can help towards a significant saving in materials compared to buying box quantites. Typical design drawing showing LED population 91 Avoiding contributing to light pollution Light pollution is caused when artificial light has been poorly designed or installed and can have serious physiological and ecological effects on individuals and their surroundings. Light pollution or more accurately obtrusive light affects the environment in three ways Sky Glow The brightening of the night sky above built-up areas. Glare The contrast between an overly bright light source when viewed against a dark background. Light Trespass The spilling of light into areas not intended to be illuminated. Back-lit advertising signs rarely create problems with sky glow or light trespass but can contribute to glare if the light source is too strong or the face material too translucent. LED modules are fast becoming the preferred lighting medium for back-lit signs in place of traditional fluorescent lamp illumination. LED luminance measured in candela per sq. metre whilst still maintaining a strong visual impact is usually significantly lower than its fluorescent counterpart and this change has helped greatly in reducing glare and light trespass. Overhead trough lighting and LED flood lighting can still create problems with sky glow and light trespass but a well-designed and positioned luminaire will go a long way to alleviating any potential obtrusive light issues. Whatever the light source a few simple rules to follow at the design stage can make a big difference. 92 09 Sign Design Avoiding contributing to light pollution Do not use more light than is necessary. Just enough illumination will not only cut down on light pollution it will also reduce energy consumption and carbon footprint. Switch off or reduce lighting when not required. A sign advertising a retail space need not necessarily be lit 24 hours per day and the luminance required in daylight could be significantly reduced as daylight fades by means of a phased dimmer linked to a light sensor. Use specifically designed luminaires that minimise upward spread of light near to or above the horizontal. Luminaires manufactured with downward reflectors are becoming more widely available and will reduce light spill and glare to a minimum. Organisations like the International Dark Sky Association are raising awareness of the problems of light pollution. For information go to 93 10 Applications Light Emitting Diodes are now considered to be the first choice option for the illumination of channel-lit built-up letters. Continuing product improvements in light output energy consumption and unit cost has resulted in LEDs replacing other lighting options almost completely. Modular LED systems are now available in high brightness White in a range of colour warmths generally ranging from 3200k up to 7500k as well as the standard Red Blue Green and Amber Yellow colour range. Certain specialist colours can be manufactured to match a specific corporate identity although LED manufacturers will usually require commitments to large production batches. RGB Red Green Blue colour changing LEDs can effectively mix any colour in the visible spectrum. With a greater emphasis from the major manufacturers on optical lens technology LEDs can now be used at much wider module spacings subsequently reducing the quantity of product required. The improvement in spread of light that innovative lenses can offer means that letters can be fabricated at shallower return depths than ever before without the fear of diode spotting. This also helps to reduce the overall cost per letter. LEDs consume far less energy than traditional means of lighting such as Hot Cathode Fluorescent lamps and as the light output to cost ratio improves applications such as back lighting large-format Flexface signs are becoming more viable. A quality LED system if correctly installed will provide bright eye catching visual images that will remain virtually maintenance free for years to come. 94 LED Fitting into letters Since LED was first introduced to the sign industry in the early nineties it brought with it the opportunity to provide illumination to channel letters which in the past were too small to be lit with cold cathode tubing thus extending the market for illuminated signs. Many small to medium sized sign making companies were previously reluctant to involve themselves with high voltage installations and therefore would not have considered offering illuminated lettering to their customers. They are now presented with an opportunity to exploit a whole new market. In order to take full advantage of this opportunity companies should be made aware of the strengths weaknesses and potential pitfalls of using different LED systems. LEDs by their nature provide a single point of light. In order to produce an even illumination diode spacings Lenses return depths background material and light transmission of the face material all play a major part. Every LED system is made up of diodes supplied either singly on a string at varying spacings or grouped together on a board or module. LEDs can emit their light at varying viewing angles typically between 90 and 150 degrees and if fitted with an optical lens the light can be manipulated to focus a more homogeneous spread on the sign face. The wider the viewing angle the more opportunity there is for the individual light sources to merge although beyond 150 degrees the effect is negligible. The narrower the viewing angle the more intense the light source will appear. Some systems are designed specifically for outdoor use and some are only suitable for indoor applications. Even if the LED is installed into channel letters with back trays this will not provide sufficient weather protection and can dramatically reduce the operating life of the LED and therefore require outdoor rated systems. IP ratings on LED systems are not a good indicator as to their outdoor reliability although IP66 and above should be considered the minimum acceptable. 95 10 Applications LED Fitting into letters Left Halo illuminated lettering. Right Face illuminated lettering. Based on the above it is clear that no single LED system will provide a suitable solution to all applications and a decision needs to be made at the design stage as to which system will best suit the particular application. The sign maker should seek advice from the LED supplier before embarking on any new project. A technically competent supplier will be able to offer detailed recommendations based on the system they distribute. The wider the choice of systems the supplier has the more likely he is to be able to provide the perfect solution. Whilst choice of LED product is crucial to producing the desired effect there are certain general factors that should be taken into consideration when designing a sign with illuminated lettering Halo illumination Background fascia material should not be glossy because this has a tendency to reflect individual spots of light rather than a uniform halo. Dark backgrounds will absorb most of the light and will inevitably result in a disappointing finish. Letters with a narrow stroke width and deep returns will tend to channel light directly behind the letter and will not allow a broad halo to develop. Built-up letters should ideally be fitted with back-trays. This gives the option to fit the LED to the inside face of the back-tray facing into the letter and bouncing back to give a more uniform light spread Fixings on the back- tray should be made from clear acrylic blocks rather than aluminium angle 96 10 Applications LED Fitting into letters section so as to avoid shadowing of the halo. Back-trays can also be covered with a light diffusing material if required. The inside of metal letters should be painted white to optimize light output. Flat-cut letters with Simplefix locators are not an ideal option for halo illumination. The stand-off distance is not sufficient to provide an even glow and unless the LED has a very low profile it will be visible when viewing the sign from the side. Figure 32 Halo illuminated lettering typical installation Built-up stainless steel letter Toggle fixings through cladding panels Opal acrylic back tray LED modules providing halo illumination Letters mounted to composite cladding panels 97 10 Applications LED Fitting into letters Face illumination Return depth of the channel letter is critical to the choice of LED system as an even face illumination is required for this type of installation. It is possible with high powered LEDs to illuminate letters with returns in excess of 250mm. However with the systems currently available return depths of less than 35mm can prove challenging. All face illuminated letters should be fitted with back trays in order to provide added protection to the diodes and make installation a little simpler. The choice of material suitable for back trays is wide and varied as nowadays there is no need to fit LEDs to metal backings. Most modules are now supplied with their own in-built heat dissipation systems and any that do require external thermal management should be considered unfit for purpose. There are acrylics on the market such as Plexiglas TruLED which are specifically designed for illumination with LEDs although the range of colours available at present is limited. These acrylics will provide significantly improved levels of illumination when used with the correct colour LED. Cool White LED will illuminate most acrylic colours to a satisfactory level but improved results are often obtained by using different colour warmths or matching LED colour to acrylic colour Figure 34. 98 10 Applications LED Fitting into letters Figure 33 Face illuminated lettering typical installation 0.9mm brushed stainless steel return Clear silicone bonding 5mm Opal 050 acrylic faces 20mm long stand-off space White 7100K LED modules White Dibond back tray 99 Back-lit Lightboxes Back-lit lightboxes are possibly the most popular types of illuminated signage providing a relatively simple means of enhancing brand identity. Sign cases are mainly fabricated from extruded aluminium sections in typically two return depths of approx 100mm or 200mm. The extrusion is designed to accept rigid acrylic sheet in 3mm or 5mm thicknesses or in the case of flexible substrates a proprietary tensioning system. Fret-cut sign cases are generally made up of a single aluminium sheet with folded returns. The fret-cut portions are than backed up with a translucent acrylic. Return depths typically range from 75mm to 250mm. 0 20 40 60 80 100 120 120 90 70 50 30 10 -20 oflightoutput Degrees Fahrenheit LED Standard T8 T8 High Output 100 10 Applications Back-lit Lightboxes Many lightboxes are still lit with T8 or T5 Fluorescent lamps but as costs continue to increase on lamps and ballasts LED costs and energy efficiencies are improving almost on a daily basis. This is leading to LED modular systems becoming an increasingly popular method of illumination even for the largest lightboxes. Climatic conditions can have a significant effect on the performance of different lighting products. As external temperatures drop below 15 degrees C the light output from a T8 Fluorescent lamp can reduce by as much as 80 whereas the light output from a modular LED system will increase as it gets colder. The graph on page 99 illustrates how much low temperature can affect brand image. Most High Street Retail Brands have now made the decision to convert their whole estate to LED illumination due to the significant energy cost savings that can be made. Initiatives such as the Enhanced Capital Allowance Scheme via The Carbon Trust also provide significant incentives to switch to a greener technology. As LEDs improve in terms of light output per module and innovative lens technologies help to ensure that the light is used more efficiently other component parts of the lightbox are developing to keep pace and take maximum advantage of this lighting revolution. In the past Fluorescent lamps tended to provide too much light effectively washing out much of the face image. Sign makers compensated for this by using a face material with a low transmission value which cancelled out a high percentage of the light. Obviously this was not a major issue when energy was cheap and the need to show green credentials was not particularly fashionable but nowadays the emphasis is on providing the optimum visual image for the minimum energy consumption. Acrylic manufacturers have risen to the challenge introducing LED compatible substrates which in certain applications have increased light transmission values from 37 as in the ubiquitous 050 to its LED counterpart with a transmission value of 59. 101 10 Applications Back-lit Lightboxes The chart above details the light transmission values for Opal acrylic substrates stated by different manufacturers. LED compatible acrylics are designed to have a higher diffusion factor than standard acrylics helping to spread the point light sources more evenly across the sign face. LED compatible coloured acrylics are also formulated to more closely match the wavelengths of the typical coloured LED range ie Red 625nm Green 530nm Blue 467nm allowing more of the light to be transmitted. Self-adhesive vinyl manufacturers are beginning to introduce films specifically for use with LED back-lit signs. One particular manufacturers White film boasts a 43 transmission value. Advancements in Flexible substrate light transmissions are less forthcoming and in general are still in the region of 20. Differing results can be achieved either by covering the Flex face with translucent film or by digital printing straight to the face. Whichever type of LED back-lit sign is chosen there are a few basic rules to ensure that the light on the sign face is as bright and even as possible Colour Ref. Light Transmission Perspex 050 Plexiglas WM34 Acrycast A005 37 Perspex 040 Plexiglas WM13 Acrycast A004 51 Perspex 030 Plexiglas WM22 Acrycast A003 70 Perspex 028 Plexiglas WM11 Acrycast A002 26 Perspex 1TL2 59 Perspex 1T04 32 Plexiglas WH14 47 Plexiglas WH72 31 102 10 Applications Back-lit Lightboxes Signs with large surface areas of a single colour should have deeper returns to allow the point light sources to have more opportunity to diffuse. Choose an LED system with optics and beam angle that suit the box return depth. Clarify with the LED supplier the recommended moduleline spacings best suited for the specified return depth. Ensure that the inside of the light box is coated white to ensure maximum reflection. Keep structural supports within the box to a minimum as they can create shadows on the sign face. Try to pre-mount the LED modules to a white substrate such as Dibond or Foamex. This helps with reflectance and also ensures that all the modules are the same distance away from the sign face. Light boxes with digitally printed photographic images can be further enhanced by opting for an LED colour which better suits the particular image. eg colder temperatures for Wintery images and warmer temperatures for Summery images. LED modules are now available as standard in a range of Kelvin temperatures from 3000K through to 7100K. 103 Edge-lit lightboxes Edge-lighting has developed over recent years into a system that can provide excellent results in small to medium size boxes with shallow returns and is a particularly good solution for double-sided projecting signs. Edge-lighting LED systems are now available from all the major lighting brands and basically comprise of modules with optical lenses designed to throw the light across the sign by means of a narrow beam light distribution pattern rather than the backlighting method utilising the Batwing pattern. These modules fit into the side walls of the light box and can be fitted to one two or all four sides depending upon box size required light output and budget. The benefits of using this type of system are Uniform backlighting across the sign face on small to medium size boxes. Works well on shallow return light boxes. Provides excellent results with fret-cut aluminium sign cases. Uses less modules reducing cost and energy consumption. Easier installation especially with double-sided boxes. Edge-lighting works by means of reflected light and so it is crucial that all surfaces within the light box are painted white and that the box itself has the minimum number of structural supports which will restrict the passage of the light. Any modules that are fitted along the bottom of a light box which is being installed outdoors should be raised up sufficiently to prevent the modules from being immersed in water. Particular attention should be paid to ensuring that there are sufficient drainage outlets in the box. This applies to 104 10 Applications Edge-lit lightboxes all manufacturers systems as even modules with a stated IP68 rating will not last long if they are under water. Most modules are supplied with a self-adhesive hi-bond backing but this should not be relied upon to hold modules that are fitted hanging upside down or to vertical sides where mechanical fixings should be used. In order to avoid unsightly rivet heads or screws protruding through the sides of the lightbox it may be worthwhile to mechanically fix the modules to a separate panel with a larger surface area and then bond that panel to the inside of the box. This method will also help with light reflection if a white panel is utilised. These systems cannot at present be used with larger lightboxes in excess of 2000mm high because the spread of light is not sufficient to reach the centre of the box however as LED light out increases and lens technologies continue to develop the opportunities to utilise this lighting method will continue to increase. 105 LED Edge-lit panels There are basically two types of effect possible using acrylic panels edge-lit with LED strips. The first option is to engrave or etch lettering or detail into the panel and illuminate along one edge to create a simple glowing feature sign. The LEDs can be incorporated within an aluminium extrusion allowing for either a hanging or desk mounted option. Multiple colour sign panels can be produced by using a number of acrylic sheets each engraved with part of the detail pertaining to the particular colour and then separately edge-lit with a different colour LED strip. The separate acrylic sheets are then sandwiched together to create the multi-colour sign panel. The second and more common use for edge-lit panels is to provide a full back lighting solution for very shallow return lightboxes. This method works in a similar way to the above except that the whole surface area of the acrylic panel is laser-etched with a specially designed pattern which re-directs the light from the White LEDs on the edge of the panel to the sign face. This surface can then be topped with an Opal acrylic panel or a translucent digital printed image. Once a separate frame has been added you are left with a neat slim lightbox which can be as shallow as 10mm. Increases on brightness can be achieved by having LEDs fitted along more than one edge but this can result in a significant increase in cost per solution. 106 10 Applications LED Edge-lit panels Other lighting features can be created by using RGB colour changing LEDs. This is particularly useful for creating innovative solutions in retail display applications. The drawbacks with edge- lit panels are that the LEDs used are generally only suitable for internal applications and there are limitations to the sizes of laser-etched acrylic panels available. 107 LED Floodlights LED Floodlights can offer a versatile solution to many outdoor lighting applications such as wall washing billboard face lighting and sports court area lighting. These systems generally comprise high brightness LEDs typically in excess of 5000 Lumens encased in a cast aluminium housing which also acts as an additional heat sink. The housing should have an ingress protection rating of at least IP65. Floodlights can be supplied in a range of LED wavelengths but the majority come in a warm white of approx. 4000K with a Colour Rendering Index of at least 75 CRI so that the emitted light replicates as closely as possible to natural daylight. LED Floodlights can offer significant energy savings over traditional High Intensity Discharge HID lamps the most efficient offering savings in excess of 80. Arrays of different optical lenses are available so that the light can be manipulated to best suit the particular application. See Figure 35 overleaf. Floodlights can be supplied with or without photoelectric sensors which can be set to switch on and off as ambient light levels rise or fall. Most floodlight systems are supplied with a choice of mountings to best suit the particular application. 108 10 Applications LED Floodlights Figure 34 Light output diagrams for LED lenses - supplied courtesty of Nova Aluminium EFMR BillboardBulletin BU 5600 Lumens 4300K GE454635.ies Max Candela 9797 Vertical Angle 12.5 H Horiz. Axial Candela V Vert. Axial Candela Grid Distance in Units of MH at 10 and 15 tilt EFMR Narrow Spot NS 5600 Lumens 4300K GE454636.ies Max Candela 23921 Vertical Angle 0 H Horiz. Axial Candela V Vert. Axial Candela Grid Distance in Units of MH at 10 and 45 tilt 109 10 Applications LED Floodlights EFMR Wide Flood WF 5600 Lumens 4300K GE454637.ies Max Candela 5165 Vertical Angle 12.5 H Horiz. Axial Candela V Vert. Axial Candela Grid Distance in Units of MH at 25 and 45 tilt 110 Overhead LED trough lighting Trough lights with Fluorescent lamps have been popular for some time as a cost effective means of illuminating long fascia runs or billboard advertising hoardings. Until recently the relatively small number of lamps required per square metre of sign made it difficult for an LED option to stack up in terms of energy savings and payback. In order to make LED installation viable manufacturers needed to rely on older technologies such as 5mm diodes which in turn suffered with reliability issues and low light levels. The very nature of LEDs being a point source of light has traditionally made it difficult to produce a downlight that did not show sign of spotting on the sign face. However as LEDs have been developed and become more cost effective the cost of Fluorescent lamps and gear has increased. This squeezing effect has helped to make the LED option become more attractive. Also manufacturers have developed methods to help spread the lighting more uniformly such as prismatic diffusers as well as making use of LED modules with wider beam angles. Costs have reduced to the extent that two rows of LEDs are sometimes installed to increase light output and improve uniformity. Most manufacturers now supply trough light aluminium extrusions which are designed to accommodate either fluorescent or LED illumination with power supplies integrated in the extrusion. Stand-off brackets are now designed with adjustable tilt features and telescopic arms which allow for adjustment of the down light to best suit the facia. 111 11 Standards Testing Classification Standards Disclaimer. The comments below are broad overviews of the standards to allow readers to decide whether they need to refer to the original document. They are not a replacement for the original nor should any inaction or action be based on these notes the originals should be referred to establish any detailed requirements. Below are briefly outlined some of the British BS and European EN Standards which apply to signs and sign illumination. There is a proposal to write a pan European standard for signs similar to BS 559 to cover none -electrical minimum safety issues with sign design construction and installation. However as of the beginning of 2015 that is still only a proposal. At draft stage but not yet out for public comment as of March 2015 is a European standard EN covering the minimum safety aspects of the electrical requirements for signs operating at low voltage less than 1000 V. This is intended to sit beside BS EN 50107 the high voltage sign standard. 112 BS 559 Specification for the design and construction of signs for publicity decorative and general purposes This is a British standard that does not apply elsewhere in Europe there may be equivalent local standards. Last reviewed in 2009 there are additions covering inspection and maintenance in the pipeline as of March 2015. Some of the content has been superseded by the introduction of the Eurocodes for the structural requirements for resistance to wind pressure etc. for signs and their supports. However the remainder is still valid and covers such matters as - Service Life Minimum material specifications for Petrol stations Metals Wood and wood laminates Plastics Glass Aluminium composite material Design and construction Illuminated signs Marking and literature 113 HD 60364 and BS 7671 Requirements for Electrical Installations the IET wiring Regulations HD 60364 is a document harmonised across Europe and therefore applicable in all European countries. There are some local differences but in the UK it is published as BS 7671 the IET Wiring Regulations. Recently changed from the IEE wiring Regulations to the IET Wiring Regulations this large tome covers all aspects of electrical installation. However there are a number of references to signs including the need for Firefighters switches for some high voltage installationsdischarge lighting installations and requirements on the supply side of an illuminated sign. Although not statutory HD 60364 may be used in court in evidence to claim compliance with a statutory requirement. 114 IEC 62347-2-13 Lamp control gear. Particular requirements for electronic gear for LED modules This International Standard equivalent to BS EN 61347-2-13 describes the minimum safety requirements for control gear for LED modules. The sign maker need not be intimately familiar with its content but might want to have an overview knowledge and would certainly be sensible to ensure all his purchased drivers conform and have the relevant CE marking paperwork on file. The standard covers such areas as- Terms and definitions General requirements General notes on tests Classification Marking Protection against accidental contact with live parts Terminals Provisions for protective earthing Moisture resistance and insulation Electric strength Thermal endurance test for windings of ballasts Fault conditions Transformer heating Construction Creepage distances and clearances Screws current carrying parts and connections Resistance to heat fire and tracking Resistance to corrosion Appendices on various issues It should be noted that there are a number of references to BS EN 61347-1 the general and safety requirements for control gear for any type of lamp. 115 IEC 62384 DC and AC supplied electronic control gear for LED modules. Performance requirements This international standard specifies performance requirements for electronic control gear for LED modules. It applies to both constant voltage and constant current types. It includes- Terms and definitions General notes on tests Classification Marking Output voltage and current Total circuit power Supply current Impedance at audio frequencies Endurance Tests A guide to quoting product life and failure rate Normative references The guide to quoting product life and failure rate is worth quoting- To allow the lifetime and failure rate of different electronic products to be meaningfully compared by a user it is recommended that the following data be provided by the manufacturer in a product catalogue a. The maximum surface temperature symbol tl t-lifetime of the electronic product or the maximum part temperature which affects product life measured under normal operating conditions and at the nominal voltage or at the maximum of the rated voltage range that allows a life of 50 000 hours to be achieved. Note. In some countries such as Japan a life of 40 000 hours should be applied. b. The failure rate if the electronic product is operated continuously at the maximum temperature tl defined in a. Failure rate should be quoted in units in time fit. 116 11 Standards Testing Classification IEC 62384 For the method used to obtain the information given in a and b above mathematical analysis reliability test etc. the manufacturer should on request provide a comprehensive data file containing the details of the method. 117 LM79 LM79 is the approved method for the Electrical and Photometric Measurements of Solid-State Lighting Products This is an internationally recognised method describing the procedures to be followed and precautions to be observed in performing reproducible measurements under standard conditions of total luminous flux electrical power luminous intensity distribution and chromaticity of solid-state lighting SSL products for illumination purposes. This approved method covers LED-based SSL products with control electronics and heat sinks incorporated ie those devices that require only AC mains power or a DC voltage power supply to operate. The test report should list all significant data for each LED product tested together with performance data. The report should also list all pertinent data concerning conditions of testing type of equipment SSL products and reference standards. Typical items reported are a Date and testing agency b Manufacturers name and designation of SSL product under test c Measurement quantities measured total luminous flux luminous efficacy etc. d Rated electrical values clarify AC frequency or DC and nominal CCT of the SSL product tested e Number of hours operated prior to measurement 0 h for rating new products f Total operating time of the product for measurements including stabilisation 118 11 Standards Testing Classification LM79 g Ambient temperature h Orientation burning position of SSL product during test i Stabilisation time Photometric method or instrument used sphere- photometer sphere-spectroradiometer or goniophotometer k Designation and type of reference standard used wattage lamp type intensity distribution type - omni-directionaldirectional and its traceability l Correction factors applied e.g. spectral mismatch self-absorption intensity distribution etc. m Photometric measurement conditions for sphere measurement diameter of the sphere coating reflectance 4p or 2p geometry. For goniophotometer photometric distance n Measured total luminous flux lm and input voltage V current A and power W of each SSL product o Luminous intensity distribution if applicable p Color quantities chromaticity coordinates CCT andor CRI for white light products q Spectral power distribution if applicable r Bandwidth of spectroradiometer if spectral distribution andor color quantities are reported s Equipment used t Statement of uncertainties if required 119 11 Standards Testing Classification LM79 Typical LM79 Test report - page 1 - further content is shown on the following eight pages Lamp specifics Luminaire Used Rated Voltage Lamp Type Rated CCT New Product Orientation Requester Current burn time Sample Size Date of Tests Test Purpose Electrical and Photometric tests as required by IESNA LM-79 test standard Standards used Disclaimers This report contains data that are not covered by the NVLAP accreditation. The measurement laboratory is currently accredited by NVLAP to all the standards under the Standards used section except LM-79. The accreditation to LM-79 is currently in progress. This report must not be used by the customer to claim product certification approval or endorsement by NVLAP NIST or any agency of the federal government. The laboratory that conducted the testing detailed in this report had been Qualified Verified and Recognized for LM-79 Testing for ENERGY STAR for SSL by US DOEs CALiPER program. e-mail phone 216-266-8958 Test Request Number 0980061 10262009 83 x 3 Lumens Mike Wise Bob Schall Phil Ellis Yan Chu none GEWHSSP3-65K 6 E. Z. Cola Measurements performed by one or more of the following authorized operators Report was checked and issued by Mihaly Kotrebai Ph.D. Senior Scientist IESNA LM-16-1995 Practical Guide to Colorimetry of Light Sources IESNA LM-20-1994 Photometric testing of reflector type lamps IESNA LM-58- 1994 Spectroradiometric Measurements IESNA LM-79-2008 Approved method for the Electrical and Photometric Measurements of Solid-State Lighting Products CIE Pub. 13.3-1995 Method of measuring and Specifying Color Rendering of Light Sources CIE Pub. 15-2004 Method of measuring and Specifying Color Rendering of Light Sources ANSI C82.2-2002 Ballast for Fluorescent Lamps-Methods for Measurement ANSI C82.77-2002 Harmonic Emission Limits- Related Power Quality Requirements for Lighting Equipment Luminaire none Watts approx. 1.1 x 3 Watts Lamp Orientation Test Requester Rated Voltage Sample Size Beam Angle Date of Tests Center Beam na Curent Burn Time 24 hr CCT 6500 K Rated Lumens 83 x 3 Lumens 6 10262009 VBD approx. 135-145 deg GEWHSSP3-65K 12 V DC at 350mAE. Z. Cola LM-79 Test Report GE Consumer and Industrial - Lighting Engineering Support Operations 1975 Noble Rd. East Cleveland OH 44112 NVLAP Lab Code 100398-0 Page 1 of 9 120 11 Standards Testing Classification LM79 Typical LM79 Test report - page 2 - further content is shown on the following pages Test Request Number 0980061 LM-79 Test Report GE Consumer and Industrial - Lighting Engineering Support Operations 1975 Noble Rd. East Cleveland OH 44112 NVLAP Lab Code 100398-0 Instrumentation Goniometry instrumentation Sphere Spectroradiometry instrumentation Test objective Goniometric measurement Sphere spectroradiometric measurement California Instrument Model 4500 AC power source Calibrated mercury thermometer Yokogawa 2010 Digital power meter or equivalent LSI High Speed Moving Mirror goniophotometer 25 Test distance Lambda Gen 1 1500W DC power source Pacific AT series AC power source or equivalent Calibrated mercury thermometer Keithley Digital multimeter Calibrated Shunt resistor NIST 300W A-line luminous Flux and Spectral Flux Standard omni-directional source NIST certificate 844274170-07 OL 770 Spectroradiometer 50 micron slit FWHM 2nm Yokogawa 2010 Digital power meter or equivalent Measure sphere photometry and input electrical parameters and report the total flux output lumens Correlated Color Temperature CCT Color Rendering Index CRI Chromaticity Coordinates xy Spectral Power Distribution SPD voltage V current A and power W Measure distribution photometry and input electrical parameters and report candela distribution calculated lumen output voltage V current A and power W NIST 300W A-line luminous Flux and Spectral Flux Standard omni-directional source NIST certificate 844274170-072 Sorensen DLM 150-4 DC power source Agilent 34970 Data Acquisition unit Calibrated Shunt resistor 1.5-2 meter sphere with high reflectance coating Page 2 of 9 121 11 Standards Testing Classification LM79 Typical LM79 Test report - page 3 - further content is shown on the following pages Test Request Number 0980061 LM-79 Test Report GE Consumer and Industrial - Lighting Engineering Support Operations 1975 Noble Rd. East Cleveland OH 44112 NVLAP Lab Code 100398-0 Test Procedures and conditions Goniometry Sphere Spectroradiometry Spatial correction factor applied to lamp measurement 1 Stabilization time during testing for each lamp 1.25 Hours Stabilization time during testing for each lamp 1.25 Hours LSI type C High Speed Mirror Goniometer was used to measure intensity candela at each angle of distribution Burn time during testing for each lamp 1.25 Hours Electrical conditions and physical orientation were set as required by the lamp manufacturer or the customer Ambient temperature was controlled at 25-1 degree Celsius and measured at the approximate height of the sample mounted on the Goniometer equipment Calibration was based on National Institute of Standards and Technology certified total luminous flux standard and maintained by a set of incandescent reflector working standard laps Lamps were stabilized per LM-79 requirements Optronic 770 Spectroradiometer attached to a 1.5 or 2 meter sphere painted with high reflectance paint was used to measure correlated color temperature chromaticity coordinated color rendering index total luminous flux and spectral power distribution. Sphere measurement was set up in 4 geometry and used continuous self-absorption correction. Burn time during testing for each lamp 1.25 Hours Electrical conditions and physical orientation were set as required by the lamp manufacturer or the customer Ambient temperature was controlled at 25-1 degree Celsius and measured inside of the sphere shielded from direct radiation of the lamp Calibration was based on National Institute of Standards and Technology certified total spectral flux standard and maintained by a set of incandescent working standard lamps. Lamps were stabilized per LM-79 requirements Page 3 of 9 122 11 Standards Testing Classification LM79 Typical LM79 Test report - page 4 - further content is shown on the following pages Test Request Number 0980061 LM-79 Test Report GE Consumer and Industrial - Lighting Engineering Support Operations 1975 Noble Rd. East Cleveland OH 44112 NVLAP Lab Code 100398-0 Sphere Spectroradiometry Test Data Spectral Power Distribution 0.0000 0.0010 0.0020 0.0030 0.0040 0.0050 0.0060 0.0070 0.0080 0.0090 380 420 460 500 540 580 620 660 700 740 780 nm Wattsnm nm Wattsnm nm Wattsnm nm Wattsnm nm Wattsnm nm Wattsnm 380 0.00003 465 0.00297 550 0.00379 635 0.00172 720 0.00023 385 0.00002 470 0.00205 555 0.00381 640 0.00156 725 0.00019 390 0.00003 475 0.00134 560 0.00378 645 0.00140 730 0.00017 395 0.00001 480 0.00096 565 0.00374 650 0.00126 735 0.00013 400 0.00003 485 0.00081 570 0.00370 655 0.00112 740 0.00012 405 0.00005 490 0.00079 575 0.00362 660 0.00100 745 0.00010 410 0.00009 495 0.00094 580 0.00354 665 0.00091 750 0.00009 415 0.00016 500 0.00124 585 0.00344 670 0.00079 755 0.00010 420 0.00033 505 0.00166 590 0.00329 675 0.00070 760 0.00007 425 0.00067 510 0.00212 595 0.00315 680 0.00063 765 0.00005 430 0.00133 515 0.00257 600 0.00299 685 0.00055 770 0.00005 435 0.00231 520 0.00295 605 0.00281 690 0.00050 775 0.00006 440 0.00372 525 0.00326 610 0.00264 695 0.00044 780 0.00004 445 0.00588 530 0.00349 615 0.00245 700 0.00037 450 0.00805 535 0.00365 620 0.00225 705 0.00033 455 0.00733 540 0.00373 625 0.00208 710 0.00029 460 0.00468 545 0.00378 630 0.00190 715 0.00026 Lamp Volts Lamp Current Lamp Watts Power Factor Lumens LPW CCX CCY u v Duv CCT CRI 12 0.261 3.1 1.00 225.6 71.9 0.3168 0.3290 0.2007 0.4689 0.0011 6289 73.5 Page 4 of 9 123 11 Standards Testing Classification LM79 Typical LM79 Test report - page 5 - further content is shown on the following pages Test Request Number 0980061 LM-79 Test Report GE Consumer and Industrial - Lighting Engineering Support Operations 1975 Noble Rd. East Cleveland OH 44112 NVLAP Lab Code 100398-0 CIE 1931 xy Chromaticity Diagram -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Planckian Locus Test lamp Illuminant A 20000 K 10000 K 5000 K 3000 K 2000 K 1000 K Page 5 of 9 124 11 Standards Testing Classification LM79 Typical LM79 Test report - page 6 - further content is shown on the following pages Test Request Number 0980061 LM-79 Test Report GE Consumer and Industrial - Lighting Engineering Support Operations 1975 Noble Rd. East Cleveland OH 44112 NVLAP Lab Code 100398-0 Goniometry Test Data Polar Plot Volts Amps Watts Power Factor 12 0.2620 3.14 1.00 2.42 Max 52.5 151.00 58.00 227.14 50 of Max 26.2 107.29 145.42 229.56 10 of Max 5.2 88.63 177.26 73.0 Total Downlight Lumens Total Uplight Lumens Total Lumens Total LumensWatt Half Angle Full AngleCandela Beam Angle 0 10 20 30 40 50 10 20 30 40 50 Candela Average All 0180 90270 15 30 45 60 75 90 105 120 135 150 165180 Page 6 of 9 125 11 Standards Testing Classification LM79 Typical LM79 Test report - page 7 - further content is shown on the following pages Test Request Number 0980061 LM-79 Test Report GE Consumer and Industrial - Lighting Engineering Support Operations 1975 Noble Rd. East Cleveland OH 44112 NVLAP Lab Code 100398-0 Cartesian Plot Cone Diagram LAMP Nominal beam angle degrees 145.4 LUX at Point Distance 219 From lamp 55 0.50 Meters 3.212 24 1.00 Meters 6.424 14 1.50 Meters 9.637 9 2.00 Meters 12.849 6 2.50 Meters 16.061 4 3.00 Meters 19.273 3 3.50 Meters 22.485 3 4.00 Meters 25.698 2 4.50 Meters 28.910 5.00 Meters 32.122 Diameter Meters 32.122 Lamp to surface angle 0 Degrees Circle Diameter Meters 0.00 10.00 20.00 30.00 40.00 50.00 60.00 0 9 18 27 36 45 54 63 72 81 90 99 108 117 126 135 144 153 162 171 180 Angle Candela Average 0180 AVE 90270 AVE Page 7 of 9 126 11 Standards Testing Classification LM79 Typical LM79 Test report - page 8 - further content is shown on the following pages Test Request Number 0980061 LM-79 Test Report GE Consumer and Industrial - Lighting Engineering Support Operations 1975 Noble Rd. East Cleveland OH 44112 NVLAP Lab Code 100398-0 Candela Distribution Total 0 0.2 0.2 0.1 0.00 0 0 5 0.1 0.1 0.1 0.00 0.00 0 10 0.1 0.1 0.1 0.01 0.01 0 15 0.1 0.1 0.1 0.01 0.02 0 20 0.1 0.1 0.1 0.01 0.03 0 25 0.1 0.1 0.1 0.02 0.05 0 30 0.1 0.1 0.1 0.02 0.07 0 35 0.1 0.1 0.1 0.02 0.10 0 40 0.1 0.1 0.1 0.02 0.11 0 45 0.1 0.1 0.0 0.02 0.14 0 50 0.0 0.1 0.0 0.02 0.16 0 55 0.0 0.0 0.0 0.02 0.17 0 60 0.0 0.0 0.0 0.02 0.19 0 65 0.0 0.0 0.0 0.02 0.21 0 70 0.0 0.0 0.0 0.02 0.23 0 75 0.0 0.0 0.0 0.02 0.24 0 80 0.0 0.0 0.0 0.02 0.27 0 85 0.9 0.1 2.1 0.12 0.39 0 90 6.9 2.7 8.2 2.03 2.42 1 95 11.6 9.9 12.9 5.12 7.54 3 100 17.2 15.4 18.7 7.78 15.32 7 105 23.3 21.0 25.1 10.81 26.12 11 110 29.5 27.1 31.4 13.83 39.96 17 115 35.6 33.0 37.5 16.49 56.44 25 120 40.7 38.0 42.9 18.59 75.04 33 125 45.0 42.1 47.3 19.82 94.86 41 130 47.9 44.9 50.3 20.19 115.05 50 135 49.7 47.0 52.1 19.76 134.81 59 140 51.2 48.8 53.3 18.66 153.47 67 145 52.0 50.1 53.9 17.24 170.71 74 150 52.3 50.5 54.0 15.38 186.09 81 155 52.3 50.8 53.4 13.26 199.35 87 160 51.9 50.7 52.7 10.93 210.29 92 165 51.1 50.2 51.6 8.50 218.79 95 170 50.2 49.5 50.5 6.02 224.80 98 175 49.6 49.1 49.7 3.57 228.37 99 180 49.4 49.0 49.3 1.19 229.56 100 Zonal Lumens Cumulative LumensAngle Average cd 0180 Average 90270 Average Page 8 of 9 127 11 Standards Testing Classification LM79 Typical LM79 Test report - page 9 Test Request Number 0980061 LM-79 Test Report GE Consumer and Industrial - Lighting Engineering Support Operations 1975 Noble Rd. East Cleveland OH 44112 NVLAP Lab Code 100398-0 Individual Lamp Data Lamp ID Luminous Flux Input Voltage Current Power 0980061 - A00120090819 - 115959.spd 229.2 12.0 0.269 3.2 0980061 - A00220090819 - 124715.spd 225.8 12.0 0.264 3.2 0980061 - A00320090819 - 130749.spd 221.1 12.0 0.258 3.1 0980061 - A00420090819 - 132842.spd 223.1 12.0 0.257 3.1 0980061 - A00520090819 - 134822.spd 224.5 12.0 0.258 3.1 0980061 - A00620090819 - 140801.spd 229.7 12.0 0.264 3.2 Page 9 of 9 128 LM80 LM80 is the test for measuring Lumen Maintenance of LED Light sources. This is an internationally accepted method to permit reliable comparison of test results among laboratories by establishing uniform test methods. It provides the methods and conditions of the measurement of lumen maintenance of sources including LED packages arrays and modules only. The lumen maintenance is measured under controlled conditions and performance in a particular application may be different. This approved method does not provide guidance or make any recommendation regarding predictive estimations or extrapolation for lumen maintenance beyond the limits of the lumen maintenance determined from actual measurements. The results can be characterised by the Rated Lumen Maintenance Life Lp. The elapsed operating time over which the LED light source will maintain the percentage p of its initial light output e.g. L70 hours Time to 70 lumen maintenance. L50 hours Time to 50 lumen maintenance. 129 11 Standards Testing Classification LM80 Typical LM80 Test report - page 1 - further content is shown on the following three pages SQETM100503 Issue Date May 31 2010 Part Number NS6L083B Part Name Nichia Chip Type Warm White LED Active cooling life test system Consisting of small enclosed boxes for devices under test and watercooled heat sinks to control device temperature. LED Tester Consisting of an integrating sphere programmable currentsource meter and polychromator. The case temperature TS is the cathode lead temperature of the LED mounted on a reliability test board the ambient temperature TA is the temperature of the air at a distance of 50 mm above the reliability test board. Avg. Chromaticity Shift uv at 6000 hours Page 1 I. 55C II. 85C III. 105C LM80 Test Report Complete Actual Case Temp. TS Actual Ambient Temp. TA LM80 Required Temperature Drive Current IF Nichia Specified Temperature Number of LED tested TSTA Avg. Lumen Maintenance at 6000 hours Up to 6000 hours Measurement Current IF 130 11 Standards Testing Classification LM80 Typical LM80 Test report - page 2 - further content is shown on the following pages SQETM100503 Issue Date May 31 2010 Part Number NS6L083B Actual Temperature TS 54.7C TA 51.7C Drive Current IF 300 mA Measurement Current IF 300 mA Air flow Minimal air flow Comments No failure observed 980 h 2000 h 3000 h 4000 h 5000 h 6000 h 980 h 2000 h 3000 h 4000 h 5000 h 6000 h 78.6 3.21 101.9 102.7 102.5 103.0 102.2 101.5 0.0007 0.0009 0.0008 0.0007 0.0009 0.0008 79.6 3.25 99.1 98.7 97.7 97.6 95.5 94.8 0.0004 0.0004 0.0001 0.0004 0.0004 0.0005 77.3 3.24 99.6 98.9 97.8 97.4 95.7 94.6 0.0003 0.0004 0.0001 0.0002 0.0001 0.0003 78.3 3.25 100.6 100.5 99.7 99.7 98.3 97.3 0.0004 0.0004 0.0005 0.0003 0.0003 0.0004 78.6 3.22 102.0 102.2 102.3 102.8 101.4 101.3 0.0007 0.0009 0.0011 0.0010 0.0010 0.0010 78.4 3.22 100.3 100.3 99.7 99.9 98.5 97.4 0.0003 0.0005 0.0003 0.0004 0.0003 0.0006 79.5 3.27 100.7 100.6 99.7 99.8 98.4 97.7 0.0005 0.0007 0.0007 0.0005 0.0005 0.0006 77.6 3.25 100.0 99.5 98.5 98.4 96.7 96.1 0.0005 0.0004 0.0004 0.0004 0.0003 0.0007 78.7 3.28 100.0 98.7 98.0 98.2 97.1 96.6 0.0004 0.0003 0.0004 0.0003 0.0001 0.0003 78.4 3.23 100.6 100.4 99.5 99.7 98.2 97.6 0.0002 0.0002 0.0002 0.0003 0.0002 0.0005 n 10 10 10 10 10 10 10 10 10 10 10 10 10 10 Avg. 78.5 3.241 100.5 100.3 99.5 99.6 98.2 97.5 0.0004 0.0005 0.0005 0.0005 0.0004 0.0006 Med. 78.5 3.246 100.4 100.4 99.6 99.7 98.2 97.4 0.0004 0.0004 0.0004 0.0004 0.0003 0.0006 0.71 0.022 0.911 1.380 1.715 1.954 2.182 2.327 0.0002 0.0002 0.0003 0.0002 0.0003 0.0002 min. 77.3 3.210 99.1 98.7 97.7 97.4 95.5 94.6 0.0002 0.0002 0.0001 0.0002 0.0001 0.0003 max. 79.6 3.281 102.0 102.7 102.5 103.0 102.2 101.5 0.0007 0.0009 0.0011 0.0010 0.0010 0.0010 LLmaxet L70ln0.7Lmax Lmax L70 R2 0 h Initial Page 2 1.0139 6.0638E06 61099 0.9042 NS6L083B Lumen Maintenance Chromaticity Shift uv LM80 Test Report v lm VF V Average Lumen Maintenance 50 60 70 80 90 100 110 120 1 10 100 1000 10000 100000 hours LumenMentenance 131 11 Standards Testing Classification LM80 Typical LM80 Test report - page 3 - further content is shown on the following page SQETM100503 Issue Date May 31 2010 Part Number NS6L083B Actual Temperature TS 84.2C TA 80.9C Drive Current IF 300 mA Measurement Current IF 300 mA Air flow Minimal air flow Comments No failure observed 980 h 2000 h 3000 h 4000 h 5000 h 6000 h 980 h 2000 h 3000 h 4000 h 5000 h 6000 h 78.8 3.27 101.5 102.1 102.1 102.8 101.8 101.1 0.0006 0.0008 0.0009 0.0009 0.0010 0.0010 78.8 3.30 100.4 100.8 100.7 101.5 100.5 100.1 0.0005 0.0007 0.0007 0.0007 0.0006 0.0006 75.8 3.23 101.9 102.3 102.3 103.1 101.5 100.7 0.0007 0.0008 0.0009 0.0011 0.0009 0.0010 77.7 3.22 102.1 102.8 102.6 103.4 102.4 101.9 0.0009 0.0008 0.0008 0.0010 0.0009 0.0009 78.4 3.29 101.2 101.5 101.2 102.0 101.0 100.5 0.0009 0.0008 0.0008 0.0009 0.0009 0.0009 78.6 3.23 101.1 101.1 100.8 101.6 100.3 99.6 0.0006 0.0008 0.0006 0.0006 0.0007 0.0008 78.8 3.23 101.3 101.6 101.2 102.0 100.4 99.3 0.0008 0.0009 0.0008 0.0010 0.0009 0.0009 76.9 3.25 101.4 101.6 101.4 102.0 100.5 99.5 0.0007 0.0009 0.0008 0.0008 0.0009 0.0009 78.2 3.27 102.4 103.0 102.8 103.4 101.5 100.6 0.0005 0.0009 0.0008 0.0009 0.0008 0.0009 78.7 3.25 101.8 102.0 101.8 102.1 100.8 99.9 0.0006 0.0007 0.0006 0.0009 0.0006 0.0008 n 10 10 10 10 10 10 10 10 10 10 10 10 10 10 Avg. 78.1 3.254 101.5 101.9 101.7 102.4 101.1 100.3 0.0007 0.0008 0.0008 0.0009 0.0008 0.0009 Med. 78.5 3.253 101.4 101.8 101.6 102.1 100.9 100.3 0.0007 0.0008 0.0008 0.0009 0.0009 0.0009 1.01 0.027 0.575 0.692 0.729 0.721 0.697 0.813 0.0001 0.0001 0.0001 0.0002 0.0001 0.0001 min. 75.8 3.224 100.4 100.8 100.7 101.5 100.3 99.3 0.0005 0.0007 0.0006 0.0006 0.0006 0.0006 max. 78.8 3.300 102.4 103.0 102.8 103.4 102.4 101.9 0.0009 0.0009 0.0009 0.0011 0.0010 0.0010 LLmaxet L70ln0.7Lmax Lmax L70 R2 Lumen Maintenance Chromaticity Shift uv LM80 Test Report v lm VF V 0 h Initial Page 3 1.0224 2.1554E06 175749 0.3303 NS6L083B Average Lumen Maintenance 50 60 70 80 90 100 110 120 1 10 100 1000 10000 100000 hours LumenMentenance 132 11 Standards Testing Classification LM80 Typical LM80 Test report - page 4 SQETM100503 Issue Date May 31 2010 Part Number NS6L083B Actual Temperature TS 103.3CTA 101.5C Drive Current IF 300 mA Measurement Current IF 300 mA Air flow Minimal air flow Comments No failure observed 980 h 2000 h 3000 h 4000 h 5000 h 6000 h 980 h 2000 h 3000 h 4000 h 5000 h 6000 h 79.3 3.28 101.0 98.3 93.5 91.3 89.2 88.3 0.0011 0.0010 0.0015 0.0026 0.0032 0.0041 79.6 3.24 101.3 98.4 94.0 91.8 89.3 88.6 0.0010 0.0008 0.0015 0.0024 0.0032 0.0040 76.6 3.28 100.6 98.2 94.0 91.9 89.4 88.5 0.0010 0.0010 0.0014 0.0022 0.0031 0.0037 78.6 3.25 101.1 98.6 94.2 92.0 89.5 88.1 0.0012 0.0010 0.0014 0.0023 0.0032 0.0039 79.4 3.25 100.8 98.4 94.3 92.0 89.3 88.4 0.0007 0.0009 0.0012 0.0021 0.0029 0.0037 79.0 3.30 101.5 97.5 92.9 91.0 89.3 88.6 0.0013 0.0013 0.0022 0.0032 0.0040 0.0047 79.0 3.26 101.5 97.9 94.0 92.3 90.4 89.5 0.0008 0.0008 0.0018 0.0026 0.0030 0.0039 76.8 3.23 101.2 97.6 93.4 91.6 89.3 88.5 0.0010 0.0011 0.0015 0.0023 0.0033 0.0041 77.3 3.29 102.3 99.1 94.9 93.5 91.4 90.5 0.0010 0.0009 0.0015 0.0022 0.0031 0.0039 78.3 3.26 101.3 97.8 93.3 91.2 89.2 88.3 0.0012 0.0013 0.0021 0.0029 0.0036 0.0043 n 10 10 10 10 10 10 10 10 10 10 10 10 10 10 Avg. 78.4 3.263 101.3 98.2 93.8 91.8 89.6 88.7 0.0010 0.0010 0.0016 0.0025 0.0033 0.0040 Med. 78.8 3.259 101.3 98.2 94.0 91.9 89.3 88.5 0.0010 0.0010 0.0015 0.0024 0.0032 0.0039 1.10 0.021 0.460 0.496 0.583 0.705 0.733 0.719 0.0002 0.0002 0.0003 0.0003 0.0003 0.0003 min. 76.6 3.234 100.6 97.5 92.9 91.0 89.2 88.1 0.0007 0.0008 0.0012 0.0021 0.0029 0.0037 max. 79.6 3.297 102.3 99.1 94.9 93.5 91.4 90.5 0.0013 0.0013 0.0022 0.0032 0.0040 0.0047 LLmaxet L70ln0.7Lmax Lmax L70 R2 0 h Initial Page 4 1.0319 2.7226E05 14253 0.9631 NS6L083B Lumen Maintenance Chromaticity Shift uv LM80 Test Report v lm VF V Average Lumen Maintenance 50 60 70 80 90 100 110 120 1 10 100 1000 10000 100000 hours LumenMentenance 133 EN 50107-1 Signs and luminous discharge tube installations operating from a no-load rated output voltage exceeding 1 kV but not exceeding 10 kV. Part 1 General requirements This is the pan European reference for high voltage neon and cold cathode installations. No-one should be making or installing these signs without a working knowledge of this document. Some European countries have strict rules on the qualification of installers of high voltage signs. It covers- Means of attachment Drain holes Installation of mains supply wiring ref HD 30634 or BS 7671 above Enclosures and protection of live parts Protection against indirect contact Transformers Earth leakage and open circuit protection Inverters and converters electronic transformers Auxiliaries Insulating sleeves Specification and installation of high voltage cables High voltage connections Supports for tubes Electromagnetic compatibility Inspection and testing of installations Marking Maintenance 134 EN 61050 EN 61347-2-10 EN 50107-2 and EN 50143 These are secondary standards for suppliers and describe the specifications for- BS EN 61050. Traditional core and coil high voltage transformers for signs BS EN 61347-2-10. Lamp controlgear. Particular requirements for electronic invertors and convertors for high-frequency operation of cold tubular discharge lamps neon tubes BS EN 50107 -2. The design and operational requirements of earth leakage and open circuit devices for high voltage installations BS EN 50143. The range of high voltage cables available They are not usually directly relevant to a sign maker other than he needs to ensure his supplier supplies materials to these specifications. 135 CE Marking CE marking is a way of labelling items to confirm that they conform to the relevant European Standards or ENs. For the LED sign industry it is principally relevant to the power supplies. Using power supplies that are not CE marked is not recommended since they may not conform to relevant safety standards such as the Low Voltage Directive. In the event of an incident if a non-CE marked device has been used it is likely that- 1 The law may have been broken and a prosecution will result. 2 Any liability will be increased. 3 Insurance may be invalid. The CE marking must be supported by a suitable certificate of conformity which should- 1 Be in valid date. 2 List the standards that the device conforms to. For an LED driver these should include- a. IEC 61347-2-13 Lamp control gear. Particular requirements for d.c. or a.c. supplied electronic control gear for LED modules. b. IEC 62384 D.C. or a.c. supplied electronic control gear for LED modules. Performance requirements. c. Parts of EN61000 regarding immunity to and limits for line interference and radiated interference EMC The Electromagnetic Compatibility Regulations. d. The Low Voltage Directive. 3 Be signed off by a responsible person. 136 IP Ratings The European Standard EN 60529 covers the classification of degrees of protection provided by enclosures for electrical equipment with a rated voltage not exceeding 72.5 Kilovolts. The standard gives definitions for degrees of protection provided by enclosures of electrical equipment with regards to Protection of persons against access to hazardous parts inside the enclosure. Protection of the equipment inside the enclosure against ingress of solid foreign objects. Protection of the equipment inside the enclosure against harmful effects due to the ingress of water. The classification reference utilises the letters IP Ingress Protection followed by two digits. The First digit relates to the degree of protection afforded against solid foreign bodies intruding into the enclosure. The second digit relates to different types of moisture ingress. Where the classification for a particular enclosure only covers one type of ingress the digit is replaced with x EG IPX7 etc In the particular case of modular LED systems for signs moisture ingress due to immersion under pressure is considered irrelevant and so IP66 rating is considered to be the acceptable standard. Electronic LED drivers are also generally rated at IP66 unless a specifically rated by the manufacturer for wet locations. See overleaf for classification references. 137 11 Standards Testing Classification IP Ratings IP Ratings Level of protection against solid objects materials or dust Level of protection against water or liquids 0 No protection 0 No protection 1 Protected against solid objects over 50mm 1 Protected against vertically falling drops of water. Test carried out for 10 minutes equivalent to 1mm of rainfall per minute 2 Protected against solid objects over 12mm 2 Protected against direct sprays of water up to 15 degrees from vertical. Test carried out for 10 minutes equivalent to 3mm of rainfall per minute 3 Protected against solid objects over 2.5mm 3 Protected against direct sprays of water up to 60 degrees from vertical. Test carried out for 5 minutes 0.7 litres per minute 80-100kPa pressure 4 Protected against solid objects over 1mm 4 Protected against water sprayed from any direction limited ingress permitted. Test carried out for 5 minutes 10 litres per minute 80-100kPa pressure 5 Limited protection against dust ingress no harmful deposit 5 Protected against low pressure water jetssprayed from any direction limited ingress permitted. Test carried out for 15 minutes 12.5 litres per minute 30kPa pressure. 6 Totally protected against dust ingress 6 Protected against high pressure water jets sprayed from any direction limited ingress permitted. Test carried out for 3 minutes 100 litres per minute 100kPa pressure. 7 Protected against immersion between 150mm and 1000mm Test carried out for 30 minutes at up to 1000mm depth 8 Protected against long periods of immersion under pressure. Continuous immersion in water up to 3000mm depth IP66 and IP67 testing definitions and procedures IP66 Rating A strong water jet directed at the object from any direction must not have any harmful effects. A jet nozzle with an inside diameter of 0.49 inches splashes a volume flow of approximately 26.4 gallons per minute from a distance of approximately 8.2 - 9.8 feet from all sides onto the object. The test time is 3 minutes. IP67 Rating Immersion in water at a depth of between 150mm and 1 metre must not have any harmful effects. The test time is 30 minutes. 138 12 Legislation Guidelines In our increasingly regulated world its no surprise that standards and legislation covering signage and in particular illuminated signage should be both detailed and far-reaching. The good news is that these new standards are resulting in better working practices and better results not to mention improved safety for installers and the general public and protection against litigation. However this all comes at a cost complexity. Todays sign specifier or installer needs to be aware of a raft of legislation covering the use of materials in electrical devices and their recyclability as well as energy consumption and environmental concerns in addition to meeting basic standards of design and installation. This chapter is intended as a first introduction to legislation covering illuminated signage. Its not an exhaustive guide by any means but will point the reader in the right direction for full compliance and peace-of-mind. 139 The E.C.A. Scheme The E.C.A. Scheme is an incentive managed by The Carbon Trust and HMRC to encourage companies to invest in energy saving technologies. Amongst many other categories the scheme covers the use of White LEDs Light Emitting Diodes inlighting. It has recently been upgraded and it has come to light that the scheme can realistically only apply to luminaires used for external illumination of signs. Internally illuminated signs are no longer included in the Scheme unless they can be proven to conform to the criteria. A difficult if not impossible task. How the scheme works The end client invests in a new sign illuminated with White LEDs or decides to change the lighting in his existing sign from say Fluorescent lamps to LEDs. That sign will show on the clients balance sheet as a capital asset which in normal circumstances would be depreciated against tax at the rate of 20 per year on a reducing balance basis. However under this scheme the tax relief on this sign can all be claimed in the 1st year potentially reducing the tax liability on the capital asset by as much as 28 see chart on page 140. Whilst the terminology is slightly ambiguous the tax relief not only applies to the cost of the LED system but could also cover the cost of transporting the sign to site as well as installation and access equipment. HMRC are the final arbiters on any claim so the services of a good tax accountant are advised. The table on page 140 shows the benefits of the E.C.A. Scheme to business comparing Capital Allowance C.A. to Enhanced Capital Allowance E.C.A. based on a sample capital investment of 10000. 140 12 Legislation Guidelines The E.C.A. Scheme Capital Allowance Year 1 2 3 4 5 6 7 8 9 Capital expenditure 10000 8000 6400 5120 4096 3277 2621 2097 1678 Capital Allowance CA 20 2000 1600 1280 1024 819 655 524 419 336 CA Tax Allowance 560 448 358 287 229 184 147 117 94 Enhanced Capital Allowance Year 1 2 3 4 5 6 7 8 9 Capital expenditure 10000 0 0 0 0 0 0 0 0 Enhanced Capital Allowance ECA 10000 0 0 0 0 0 0 0 0 ECA Tax Allowance 2800 0 0 0 0 0 0 0 0 If the right LED system is chosen any claim should proceed with few problems. The E.C.A. scheme was initiated not only to encourage the use of energy saving technologies but also to ensure that LED manufacturers develop systems that are highly efficient in terms of light output energy consumption and lifespan. In order to be eligible for the scheme the chosen LED device must have a colour rendering index of at least Ra 60 and together with the control gear must comply with the recognised industry standards. The criteria list is very specific as to which testing procedures must be adhered to and a simple declaration of compliance from the supplier is not sufficient to make a viable claim. HMRC have stipulated that any claims made should be backed up by the necessary technical data. To be eligible products MUST Include one or more White solid-state LED devices luminaires and associated electronic control gear. Use electronic control gear that complies with the following standards 141 12 Legislation Guidelines The E.C.A. Scheme BS EN 61347-2-132006 Lamp control gear. Particular requirements for d.c. or a.c. supplied electronic control gear for LED modules. BS EN 623842006 D.C. or A.C. supplied electronic control gear for LED modules Performance requirements. Be CE Marked. All products MUST Have a luminaire efficacy i.e. lighting efficiency that is greater than or equal to 46 Lumens per Circuit Watt after 100 hours of continuous operation. The electrical power consumed in circuit watts is defined as the total power consumed by the whole lighting unit from main circuit connection point to LED module including losses in the power supply and constant current source and losses due to the effects of temperature. It is not the rated wattage of the LED chip. Have a colour rendering index that is at least Ra 60. Have a standby power not exceeding 1 Watt when fitted with an automatic dimming or switching circuit. If the product is not fitted with an automatic switching or dimming circuit it must not consume power when it is switched off. Have a power factor that is greater than or equal to 0.7 at all levels of product light output. Required test procedures BS EN 13032-12004 Light and lighting. Measurement and presentation of photometric data of lamps and luminaires. Measurement and file format. 142 12 Legislation Guidelines The E.C.A. Scheme Or IES LM-79-08 Electrical and Photometric Measurements of Solid-State Lighting Products. All products must be tested in accordance with the procedures laid down in one of the following and be able to provide a light output in lumens after 6000 hours of continuous operation that is not less than 90 of their initial light output in lumens. Test results carried out on the LED chip in isolation are NOT acceptable. Testing must be conducted on the complete product i.e. solid state LED devices luminaire and associated electronic control gear and under normal operating conditions. Measurements of the reduction in product light output with time shall be made according to the methods in either IECPAS 626122009 Self-ballasted LED-lamps for general lighting services Performance requirements or IES LM-80-08 Measuring Lumen Maintenance of LED Light Sources. For the avoidance of doubt test data should be presented to zero decimal places. As an example an efficacy of 45 lumens per circuit watt for a display lighting unit would be deemed a failure. Scope of Claim Expenditure on the provision of plant and machinery can include not only the actual costs of buying the equipment but other direct costs such as the transport of the equipment to site and some of the direct costs of installation. Clarity on the eligibility of direct costs is available from HMRC. 143 RoHS Compliance The denition and aim of the RoHS directive is quite simple to restrict the use of certain dangerous substances in electronic and electronic equipment. Any RoHS compliant component is tested for the presence of Lead Pb Cadmium Cd Mercury Hg Hexavalent chromium Hex-Cr Polybrominated biphenyls PBB and Polybrominated diphenyl ethers PBDE. For Cadmium and Hexavalent chromium there must be less than 0.01 of the substance by weight at raw homogeneous materials level. For Lead PBB and PBDE there must be no more than 0.1 of the material when calculated by weight of raw homogeneous materials. Any RoHS compliant component must have 100 ppm or less of mercury and the mercury must not have been intentionally added to the component. In the EU some military and medical equipment are exempt from RoHS compliance. Recently an exemption was obtained for cold cathode lamps for neon signs and lighting with certain restrictions. See page 144. Working in partnership with the Department for Business Innovation and Skills BIS the National Measurement Ofce NMO is the authority responsible for enforcing the RoHS Regulations within the UK. While each European Union member state has adopted its own enforcement and implementation policies using the directive as a guideline the six substances now restricted are listed across-the-board as lead mercury cadmium chromium VI PBB and PBDE the last two of which are used as ame retardants in some plastics. Manufacturers authorised representatives importers and distributors need to understand the requirements of the RoHS Directive to ensure that they comply. RoHS does not require any specic product labeling however many manufacturers have adopted their own compliance marks to reduce confusion. Visual indicators in use today include explicit RoHS compliant labels green leaves check marks and PB-Free markings. 144 12 Legislation Guidelines RoHS Compliance Cold cathode exemption In 2014 an exemption was obtained for lamps known as HLDT Handcrafted Linear Discharge Tubes for use in signs decorative or architectural and specialist lighting and light-artwork. The quantity of mercury is limited to differing amounts dependent on the installation environment and lamp length with a maximum of 80 mg per lamp. The legislation should be referred to to obtain precise information. 145 BREEAM BREEAM Building Research Establishment Environmental Assessment Method is the leading and most widely used environmental assessment method and rating system for buildings and communities. It sets the standard for best practice in sustainable design and has become the de facto measure used to describe a buildings environmental performance. Applicants for BREEAM include many retailers and part of their brief will be signage. If a client decides to achieve BREEAM accreditation he will certainly need from you the sign maker details of the energy consumption of your design and maybe alternatives. Reference should also be made to ILE Report No 5 and the section on minimising waste or intrusive light. He will then be able to choose the best suited system for his needs in his application to BRE. BREEAM provides clients developers designers and others with market recognition for low environmental impact buildings assurance that best environmental practice is incorporated into a building inspiration to find innovative solutions that minimise the environmental impact a benchmark that is higher than regulation a tool to help reduce running costs improve working and living environments a standard that demonstrates progress towards corporate and organisational environmental objectives BREEAM addresses wide ranging environmental and sustainability issues and enables developers and designers to prove the environmental credentials of their buildings to planners and clients. It uses a straightforward scoring system that is transparent easy to understand and supported by evidence-based research 146 12 Legislation Guidelines BREEAM has a positive influence on the design construction and management of buildings sets and maintains a robust technical standard with rigorous quality assurance and certification For more information including case studies in the retail industry see 147 Health and Safety The following paragraphs have been written with the UK in mind. However much of the content will also apply in other European countries given European Harmonisation of legislation. In addition to the basic health and safety legislation applicable to running any business the sign industry has some specific areas to cover depending on the role each company plays. Each business must assess which areas of health and safety legislation apply to it and take the necessary steps. Depending on the size and complexity of each individual business this can be achieved in a number of ways. For larger companies or sign makers within a larger group of companies a dedicated suitably qualified Health and Safety Manager may be required and feasible. Below that level a part time position may exist or an outside contractor may be suitable. In the former case enough time needs to be allocated for the health and safety management role. In the latter case care should be taken that the contractor understands the business and industry and its particular peculiarities and can design the management system and documentation accordingly and not just cut and paste irrelevant or unexplained systems and documentation from another industry there may be some opportunity to use already existing systems and documents but the whole should not be designed this way. We must include a few words on the hottest subject in the sign industry in early 2015. In recent years there have been a number of incidents of signs and their substructures falling off buildings and hitting sometimes fatally passing members of the public. These very unfortunate occurrences appear to be caused by a lack of inspection and maintenance on the signs involved. Many sign companies do not offer inspection and maintenance and therefore believe it is not their responsibility. However current thinking is that it is the responsibility of the sign maker andor provider to give 148 12 Legislation Guidelines Health and Safety the customer written guidance and inform them in writing that they have an obligation under law to maintain their sign. Recent court cases have clearly demonstrated the prime responsibility resides with the sign and site owners but sign companies maintenance companies and the brands being advertised all come under the scrutiny of any investigation. The BSGA is currently adding an amendment to BS559 and generating Guidelines to assist members on this subject. To help you establish basic health and safety management there is a host of information available from the horses mouth as it were on the HSE website. You should not be afraid of registering to receive newsletters and updates direct from them. The level and depth of information available is great. However HSE will not always tell you what is right or wrong they will expect you to assess the risk and take appropriate control measures every step of the way because the levels of risk and control measures differ from company to company and situation to situation. Below is a far from exhaustive list taken from the HSE website along with some notes as to the areas of possible relevance to the sign industry. This is not exhaustive and you must establish for yourself what is relevant to you and your company- CDM Construction Design and Management. Often applicable on new build sites. COSHH Control of Substances Hazardous to Health. Applies to the use of glues adhesives inks etc. DSE Display Screen Equipment. All offices use computer screens to varying degrees. Drugs and Alcohol. Do you have a policy in place and is it understood Electricity at work. Even a simple office uses electricity and it must used correctly. Installation of lighting in signs requires a deeper knowledge. Health Surveillance. Probably only applies to mercury in neon glass shops. 149 12 Legislation Guidelines Health and Safety LEV Local Exhaust Ventilation. Paint shop LOLER Lifting Operations and Lifting Equipment Regs. FLT Access equipment etc. Manual Handling. From boxes of printer paper upwards Musculoskeletal disorders. RSI Back Pain et. al. Noise. PAT Portable Appliance Testing. PUWER Provision of Work Equipment Regs. Drills sanders access equipment. Slips and trips. A major source of lost time accidents. Welding. Work equipment and machinery. See LOLER and PUWER above. Working at Height. Sign installation. Let us take the last one as an example. On the HSE webpage httpwww. you will find links to information on- Key messages Common work at height myths Step-by-step guide Frequently asked questions The law Your industry Types of equipment Work at height news Resources Subscribe 150 12 Legislation Guidelines Health and Safety The following HSE guidance documents can be downloaded as pdfs. Working at height a brief guide Safe use of ladders and stepladders a brief guide There is also a specific work -at-height website which can be accessed at In the latter of these in the top menu list are sections leading to various areas of guidance including- What you should consider when you subcontract work to others - which is particularly relevant to many signmakers. A checklist of things to ensure is included. Another area of particular interest to illuminated sign makers would be the Electricity at Work regulations and the decision if someone is competent. In the free download of the Memorandum of Guidance on the Electricity at Work Regulations 1989 it quotes the Regulations- No person shall be engaged in any work activity where technical knowledge or experience is necessary to prevent danger or where appropriate injury unless he possesses such knowledge or experience or is under such degree of supervision as may be appropriate having regard to the nature of the work. It goes on to explain that the scope of technical knowledge or experience may include a adequate knowledge of electricity b adequate experience of electrical work c adequate understanding of the system to be worked on and practical experience of that class of system 151 12 Legislation Guidelines Health and Safety d understanding of the hazards which may arise during the work and the precautions which need to be taken e ability to recognise at all times whether it is safe for work to continue. It cannot tell you whether a particular person is competent or not because circumstances and individuals differ but does give you the tools to take the necessary steps to establish safe working. In HSG85 Electricity at work - Safe Working Practices again freely downloaded from HSE website it gives the following advice- Select and instruct competent workers 40 Training as part of making a person competent is very important. Even the most highly qualified and capable people may not be competent to carry out specific types of work without suitable training. Competent workers will be self-disciplined and aware that reckless behaviour with electricity can lead to injury and death. 41 Those in control of the work should 1. assess the degree of competence of individual workers against the specific type of work to be done 2. provide clear instructions information and adequate training for employees on the risks they may face the measures in place to control the risks emphasising the safe system of work to be used how to follow emergency procedures 3. arrange for those being trained or those newly trained to be accompanied and supervised. 152 The Weee Directive The Waste Electrical and Electronic Equipment Directive is the European community directive 201219EU on waste electrical and electronic equipment WEEE which became European law in 2012. The WEEE Directive sets collection recycling and recovery targets for all types of electrical goods. In order to facilitate efficient recovery and disposal of WEEE with the lighting industry companies such as Osram and GE Lighting became members of Recolight a specialist lamp recycling company. LED Modular systems but at present not their associated drivers are included in the lamp recycling scheme. Recolight a not for profit organisation provides free recovery for all WEEE lamps within the UK. The recovery of electrical waste by Recolight can be carried out in a number of ways For regular large quantities of lamps Recolight can set up a free collection point. For large retro-fit projects Recolight can lease a container and collect it free of charge. For small quantities companies can dispose of their waste lamps at specific fully funded recycling points details of which are available on Recolights web site The funding for this service is initially provided by member subscription. These members in turn levy a small charge on their customers at the time of purchase which is shown as a separate charge on the invoice. At the time of writing the charge for LED modular systems is approximately 0.005p per linear metre. Suppliers or distributors making such a charge should only do so if they or the system manufacturer are subscribing members. The symbol adopted by the European Council to represent waste electrical and electronic equipment 153 Advertising Consent The following paragraphs have been written with the UK in mind. Planning laws vary from country to country and even region to region. Many European countries have stricter controls than the UK. Local requirements should always be referred to. The following information provides guidance about when to apply for consent to display outdoor advertisements and covers adverts that are excluded from control or benefit from deemed consent. It is not intended to be a complete or authoritative interpretation of the advertisement control system and as such you should always seek advice prior to undertaking works. The Local Authority Planning Applications and Advice section is responsible for the day to day control of outdoor advertisements under the Town and Country Planning Control of Advertisements Regulations 2007. Advertisements are controlled in the interests of amenity and public safety. Advertisement control covers a wide range of advertisements and signs all of which communicate information or a message to passers-by. The most common forms of advertisement are Advance signs alongside the highway Fascia signs and projecting signs on shops Menu boards at restaurants and cafes Notices announcing the visit of a travelling fair or events such as Car Boot Sales Pole signs at petrol filling stations Poster hoardings and Sign boards at factories. 154 12 Legislation Guidelines Advertising Consent Advertisements may be permanent or temporary and the intended lifespan of the advertisement may have a bearing on the requirement for consent. Advertisements are divided into 3 groups. These are Advertisements which are deliberately excluded from the planning authoritys control Advertisements which benefit from deemed consent and Advertisements which always require consent from the local planning authority. Illuminated signs and advertisements of virtually any style usually fit into group 3. All outdoor advertisements must comply with 5 standard conditions as outlined in the Regulations. They must Be maintained in a clean and tidy condition Be maintained in a safe condition Be removed carefully where so required by the planning authority Have the permission of the owner of the site or any other person with an interest in the site on which they are displayed including the Local Highway Authority where appropriate Not obscure or hinder the ready interpretation of official road rail waterway or aircraft signs or otherwise make hazardous the use of these types of transport. 155 12 Legislation Guidelines Advertising Consent Reasons for Refusal A significant proportion of applications for consent to display advertisements are refused on the grounds of amenity or public safety. Amenity is a subjective term that basically relates to the visual appearance and attractiveness of the environment including the general characteristics of the locality. Any sign or advertisement that in the opinion of the local authority detracts from the environment can be refused permission purely on the grounds that it is detrimental to the visual amenity At times it can be difficult to second guess what the planner deems unacceptable but in most cases problems arise through Poor design Clumsy or out of scale displays Inappropriate location Over-dominance and cluttered message. The successful design of advertisements relies upon the careful handling of scale materials detailed design and a comprehension of the local environment. Illuminated signage in particular requires careful consideration and the designer can at times be torn between the desire by the client for a sign that will best enhance and promote their image and the local authority planning department who are more concerned with the overall visual amenity and how the advertisement will affect the local environment. Businesses with stores in out of town retail parks will usually have little difficulty in obtaining permission for large format illuminated fascia signs 156 12 Legislation Guidelines Advertising Consent and advertisements providing they do not conflict with traffic signs and signals whereas illuminated advertisements in small towns or semi- residential locations require more subtle signage to gain approval. LED illumination in built-up letters and large Flexface signs are more likely to be given advertising consent because they tend to operate at lower light levels measured in Candelas per sq. metre when compared to Fluorescent lamps or Cold Cathode. In the past illuminated letters needed to be quite large in order to accommodate the lighting components. With the advent of LED modules letters can now be manufactured at much smaller heights and stroke widths and so can offer an illuminated solution that does not necessarily dominate its surroundings. It is not normally acceptable for illuminated signs to display any type of animation including RGB Colour change in locations where the animation could be a distraction to road users and this type of illumination should be avoided where possible. Public safety is among the frequently cited reasons for refusal of consent. Illuminated signs featuring any kind of animation are generally considered unacceptable in locations where the animation could be a distraction to road users 157 13 Neon and Cold Cathode Neon and Cold Cathode tubes and drive gear have been extensively used in the sign industry for many years. The recent introduction of LED has dramatically reduced the need for neon and cold cathode but there are still a number of applications where for practical light output efficacy or aesthetic reasons neon and cold cathode are a preferred option. In the following paragraphs we hope to explode some of the myths and misunderstandings of neon and cold cathode and assist those familiar and unfamiliar with the medium to create a superior result. First off lets stop writing neon and cold cathode just to save some paper From now on I shall use incorrectly the term neon and here is why. Traditionally in the sign industry all cold cathode type lamps of all colours were generically referred to as neon even though many do not contain neon gas. On the other hand lamps made with argon and mercury with large diameter and high running currents are referred to as Cold Cathode Lighting because lighting is their area of application. All neon lamps and Cold Cathode Lighting lamps operate via cold cathode technology. The use of a hollow cold cathode as opposed to the coiled coil filament used in hot cathode fluorescent lamps and CFLs was introduced in the late 1890s and early 1900s leading to the patent by Georges Claude. The tubes used various filling gases including nitrogen and carbon dioxide Moores Tubes. Modern neon is usually filled with neon gas for the traditional orangered glow and similar red or orange colours or with argon neon mixtures and a trace of mercury for all other colours. In the latter the mercury discharge creates short wave UV inside the lamp which excites the phosphors coated on the inside of the glass tube leading to a wide range of whites and colours depending on the chemistry and physics of the phosphors. Note Some people think this is the hazardous material phosphorous. It is not. 158 13 Neon and Cold Cathode Many Cold Cathode Lighting lamps run on low voltage less than 1000 Volts. Their larger diameter and shorter length allow this. Many sign lamps require high voltage to operate. Many years ago this led to some problems with arcing etc. Modern neon when installed to the European Standard BS EN 50107-1 see page 133 using silicone cables and earth leakage protected transformers means installations are far less prone to problems. It is still essential however for installation to be carried out by a knowledgeable person to ensure it is to standard. Application The very wide range of whites and colours diameters running currents and ability to be custom shaped makes defining applications virtually impossible. Consult your neon supplier. However the following points might assist in selecting a suitable combination 1 Tubing a Whites. Two ranges standard and tri-phosphor. The latter are more expensive but produce more light output and slightly better colour rendering. A wide range of correlated colour temperatures are available. b Colours. Wide pastel range available in pinks oranges yellows greens blues purples etc. More limited range of saturated colours due to the need to use coloured glass to achieve high colour purity. The use of coloured glass also leads to an increased cost. c The glass used varies depending on the geographical region. E.g. In general France and Spain use borosilicate high melting point glass ROW soda lime and lead free glass. 2 Parameters a Higher current more light output but there is a maximum recommended for each diameter and electrode size. 159 13 Neon and Cold Cathode b Higher diameter allows higher current to be used and more lamps metres for a given drive voltage. c Higher diameter means less sharp bends possible and difficulty fitting in small letters or enclosures. d Lower diameter generally means higher surface brightness not necessarily overall light output for a given running current. 3 Drive Gear a More efficient electronic and traditional core and coil transformers available. Note Electronic does not necessarily mean low voltage. b Running currents available for signage are 25 30 37 50 100 mA in core and coil and a similar range in electronic transformers and are selected on the filling gas neon or argonneon mixtures and mercury tube diameter and required light output. c Running currents in Cold Cathode Lighting may be 100 mA or 200 mA depending on application. d Drive voltages can be Low Voltage less than 1000 volts for large diameter andor short length lamps up to a maximum in Europe of 10000 volts. 5000 volts to earth. e Drive voltages are dictated by number length diameter and fill gas of lamps. Use a suitable calibration chart from a reputable supplier to assess which size transformer is needed. Check correct with a calibration milliameter. Note Many modern multimeters are NOT suitable. 160 13 Neon and Cold Cathode Output Voltage 8mm Tube 10mm Tube 12mm Tube 15mm Tube 18mm Tube 20mm Tube 25mm Tube 1000Kv 0.50 0.80 1.20 1.28 1.35 2.24 2000Kv 0.55 1.10 1.75 2.30 3.40 2.80 4.70 3000Kv 0.95 1.85 2.80 3.60 4.10 4.60 7.05 4000Kv 1.40 2.70 4.00 5.00 5.75 6.50 9.18 5000Kv 1.95 3.70 5.20 6.40 7.30 8.20 11.65 6000Kv 2.55 4.80 6.50 7.80 8.85 9.90 14.06 7000Kv 3.25 6.00 8.00 9.40 10.50 11.54 16.30 8000Kv 4.10 7.30 9.60 11.10 12.27 13.44 18.40 9000Kv 4.85 8.70 11.30 12.80 14.10 15.37 20.70 10000Kv 5.80 10.20 13.00 14.60 15.80 17.02 22.95 Output Voltage 8mm Tube 10mm Tube 12mm Tube 15mm Tube 18mm Tube 20mm Tube 25mm Tube 1000Kv 0.80 1.00 1.20 1.80 1.90 2.00 2.50 2000Kv 1.80 2.00 2.40 3.20 3.40 3.70 5.20 3000Kv 2.50 3.00 3.40 4.50 5.00 5.50 8.00 4000Kv 3.50 4.10 4.60 6.00 6.60 7.60 10.60 5000Kv 4.60 5.30 5.80 7.60 8.50 9.60 13.30 6000Kv 5.70 6.60 7.20 9.30 10.40 11.60 15.90 7000Kv 6.90 7.90 8.60 11.00 12.40 13.70 18.60 8000Kv 8.10 9.30 10.40 12.80 14.60 16.00 21.10 9000Kv 9.30 10.70 12.20 14.70 16.40 18.30 24.00 10000Kv 10.60 12.20 14.00 16.60 18.43 20.80 26.50 Neon filled tubes Argon Mercury filled tubes 161 13 Neon and Cold Cathode 4 Safety and Environmental concerns a Earth leakage protection on the secondary side is a requirement in all installations in Europe. b Installations shall conform to EN 50107-1 in Europe. c Cables used on the high tension side shall conform to EN 50143. d A Firefighters switch is a requirement in some countries for high voltage installations. There are exceptions depending on wattage access to supply switch and portability. e A RoHS exemption has been granted to lamps of this type with specified limits on mercury content. f At end of life lamps should be recycled via a registered waste dealer with the correct equipment. 162 14 Glossary Advertising Consent Approval by the local authority to display a sign or advertisement. Ambient Temperature The temperature surrounding an object under discussionobservation. Ampere Unit of electrical current Bat Wing lens A lens to redirect light having an angular distribution centered around a left- right symmetry plane. Beam Angle The beam angle is the degree of width that light emanates from a light source. Black Body Locus See Planckian Locus C.I.E. 1931 The International Commission on Illumination - known as the CIE from its French title is an international standardisation body on all matters relating to the science and art of light and lighting. Candela The SI base unit of Luminous Intensity. Capacitor An electrical component used to store energy in an electrical field. 163 14 Glossary Cdm2 The SI unit of Luminance Candelas per sq. metre Chip Data Electrical test information on an unpackaged semiconductor light source. Chromaticity The quality of a colour or light with reference to its purity and its dominant wavelength. CMYK A subtractive colour system used in printing comprising Cyan Magenta Yellow Black pigments. COB Chip on Board A bare LED chip mounted directly onto a Printed Circuit Board PCB. Cold Cathode A Cathode used in gas discharge lamps not heated by a filament. Colour Perception The ability of the human eye to sense the colour spectrum using a combination of rod and cone cells. Colour Rendering Index A measure of the ability of a light source to reproduce the colour of a natural daylight. Colour Spectrum The distribution of colours produced when light is dispersed by a prism. Constant Current A system that can vary the voltage across an electronic circuit to maintain a constant electric current. 164 14 Glossary Constant Voltage A circuit element where the voltage across it is independent of the current through it. Correlated Colour Temperature The temperature to which one would have to heat a theoretical black body source to produce light of the same visual color. Coulomb The SI unit of electrical charge. D.A.L.I. Digital Addressable Lighting Interface See DALI Lighting System. DALI Lighting System A network consisting of a controller and one or more lighting devices. The controller can monitor and control each light by means of a bi-directional data exchange. Diode A two terminal electronic component with low resistance to current flow in one direction and high resistance in the other. DMX 512 A standard for digital communication networks commonly used to control stage lighting effects etc. E.C.A. scheme A initiative by The Carbon Trust to encourage the use of energy saving technologies by offering Enhanced Capital Allowances via HMRC. 165 14 Glossary Earth leakage protection A method for detecting faults to earth which then disconnects the supply. Widely used in supply wiring but also specialist devices required on the secondary side of high voltage neon and cold cathode installations. E.L.V. Extra Low Voltage - An electrical standard designed to protect against electric shock. E.T.C.L. Energy Technology Criteria List - A list of required standards to enable a claim to be made for Enhanced Capital Allowances. Electroluminescence An electrical phenomenon in which a material emits light in response to the passage of an electric current or to a strong electric field. Emitted Light Visible light created when an object releases energy in the form of Photons. Energy Consumption Energy used by an electrical device to generate the desired output i.e. light heat etc. measured in Watts per hour. Flat Ray Technology Proprietary definition for optical lens systems used on Osram LED modules. Homogeneous A material that is homogeneous is uniform in composition or character. H.V or H.T. High Voltage or High Tension. Greater than 1000 volts a.c. or 1500 volts d.c. 166 14 Glossary I.L.E. Report no. 5 Report issued by The Institute of Lighting Engineers offering guidance on the reduction of light pollution. I.P. Rating Classification system for the sealing effectiveness of enclosures of electrical equipment against the intrusion into the equipment of foreign bodies i.e. tools dust fingers and moisture. IDC Insulation Displacement Connector - an electrical connector designed to be connected to the conductor of an insulated wire. IES LM-79-08 Illuminating Engineering Society approved method for Electrical and Photometric Measurements of Solid-State Lighting Products. IES LM-80-08 Illuminating Engineering Society approved procedure for the measurement of lumen maintenance testing for LED light sources including LED packages arrays and modules. Illuminance The total Luminous Flux per unit area at any point on a surface exposed to incident light. Measured in luxes. Illuminated An object or product provided or brightened with artificial light. ie illuminated advertisement. Incandescence The emission of light visible electromagnetic radiation from a hot body as a result of its temperature. 167 14 Glossary Inductor A component that stores electrical energy in a magnetic field. Inverse Square Law The intensity of light radiating from a point source is inversely proportional to the square of the distance from the source. Joule The SI unit of energy work or amount of heat. Junction temperature The highest temperature of the actual semiconductor in an electronic device. Kelvin Unit of measurement for temperature kWh KiloWatt-hour - A unit of energy consumed over time Lambertian Reflectance The property that defines an ideal diffusely reflecting surface. Lamberts Cosine Law Luminous intensity observed from an ideal diffusely reflecting surface is directly proportional to the cosine of the angle between the observers line of sight and the surface normal. LED Light Emitting Diode - Single semiconductor light source. LED Module One or more single LEDs mounted on a rigid or flexible PCB supplied with an array of covers and heat sinks. Fitted with or without diffusing optical lenses. 168 14 Glossary Light Distribution The way in which illumination of any colour or quantity is spread over a particular background. Light Output The amount of luminous power generated from a single source Measured in Lumens. Lumen A measure of the total amount of visible light emitted by a source. Lumen Depreciation The comparison between the amount of light output from a source when it is brand new to the amount of light output at a specific time in the future. Luminaire An electrical device used to create artificial light by use of an electric lamp. Luminance The amount of light that passes through or is emitted from a particular area and falls within a given solid angle Measured in Candelas per square metre. Luminate Light up an object or product with artificial light. Luminescence The emission of light not caused by incandescence and occurring at a temperature below that of incandescent bodies. Luminous An object or product lit up or illuminated. 169 14 Glossary Luminous Efficacy The quotient of the luminous flux emitted by a source of radiation and the power it consumes Measured in lumens per watt. Luminous Emittance A measure of the total luminous power emitted from a surface with a certain area. The total luminous flux per unit area Measured in Lux. Luminous Flux The measure of the perceived power of light Measured in Lumens. Luminous Intensity An expression of the amount of light power emanating from a point source within a solid angle of one steradian. Lux A measure of the intensity as perceived by the human eye Luminous Emittance of light that hits or passes through a surface. MacAdam Ellipse The region on a chromaticity diagram which contains all colours which are indistinguishable to the average human eye from the colour at the center of the ellipse. Nanometer A unit of measurement used to specify the wavelength of electromagnetic radiation equal to one billionth of a metre. Nit A unit of luminance equivalent to one candela per square metre. Ohms Law Ohms law states that the current through a conductor between two points is directly proportional to the potential difference across the two points. 170 14 Glossary Open Circuit Protection A method of detecting open circuit conditions. Specialist devices designed for use on the secondary side of high voltage neon and cold cathode installations. Optilens Proprietary definition for optical lens systems used on GE LED modules. P.W.M. Pulse Width Modulation is a commonly used technique for controlling power to inertial electrical devices. PCB Printed Circuit Board - Used to mechanically support and electrically connect electronic components using conductive pathways etched from copper sheets laminated onto a non-conductive substrate. Photometric testing Range of test procedures to determine phenomena such as Luminous Flux Luminous Intensity Chromaticity etc Pi Mathematical constant that is the ratio of a circles circumference to its diameter - Approximately equal to 3.14159. Piranha LED Rectangular LED packages typically 5mm diodes with 4 pins also known as Superflux LEDs. Planckian Locus The path that the colour of an incandescent black body would take in a particular chromaticity space as the blackbody temperature changes. 171 14 Glossary Potting A process of filling a complete electronic assembly with a solid or gelatinous compound for resistance to shock and vibration and for exclusion of moisture and corrosive agents. Potting Compound A silcone or resin based encapsulant designed to protect electronic circuitry. Power Factor Correction The power factor of an AC electrical power system is defined as the ratio of the real power flowing to the load to the apparent power in the circuit. Refraction The bending of light rays when passing through a surface between one transparent material and another. Reflected Light Visible light that reaches the eye by bouncing off a reflective surface. RGB An additive colour mixing system comprising Red Green and Blue light. Rods Cones The two types of photoreceptor within the retina. Cones provide the eyes colour sensitivity. RoHS Compliant Restriction of the Use of Hazardous Substances. The RoHS directive aims to restrict the use of certain dangerous substances commonly used in electronic equipment. 172 14 Glossary S.E.L.V. Safety Extra Low Voltage - An electronic system in which the voltage cannot exceed ELV under normal or single-fault conditions including earth faults in other circuits. S.I. The International System of Units abbreviated SI from French Le Systme international dunits is the modern form of the metric system. S.M.D. An electronic device where the components are mounted directly onto the surface of a printed circuit board PCB. Snells Law A formula that calculates light refraction as it passes through different objects. Steradian The SI unit of solid angular measure. A complete sphere consists of 4 x pi or approx 12.56 steradians. Superflux LEDs See Piranha LEDs. Thermal Management The Means of dissipating heat generated by electronic devices and circuitry in order to improve reliability and prevent premature failure. Transformer Generally a device for converting one a.c voltage into another. Specialist device for converting supply voltage to high voltage whilst limiting the secondary current in high voltage neon and cold cathode installations. 173 14 Glossary Transmitted Light Light that passes through an object changing its frequency or perceivable colour. U.L. Classification A clasification system developed by Underwriters Laboratories a non-profit organisation providing product certification test inspection and auditing procedures. Visible Spectrum The portion of the electromagnetic spectrum that is visible to can be detected by the human eye. Visual Amenity A term usually used in relation to applications for advertising consent. It is a subjective measure of the visual quality of a site or area experienced by residents workers or visitors. Volt SI unit for electric potential voltage electric potential difference and electromotive force. Watt SI unit of power defined as one joule per second. This unit measures the rate of energy conversion or transfer. Wavelength In light and other electromagnetic radiation the strength of the electric and the magnetic fields vary. The wavelength is a measure of the distance over which the variation repeats. 174 14 Glossary Weee directive The Waste Electrical and Electronic Equipment Directive aims to reduce the amount of electrical and electronic equipment being produced and to encourage its reuse and recycling. XY Coordinates A system which uses one or more numbers or coordinates to uniquely determine the position of a point or other geometric element on a manifold such as Euclidean space. 175 15 Useful contacts If you have any queries or issues youd like to discuss please email us Vink Lighting Solutions Unit 8 Beldray Park Mount Pleasant Bilston West Midlands WV14 7NH Tel 01902 409205 Fax 01902 409378 Amari Plastics plc Holmes House 24-30 Baker St Weybridge Surrey KT13 8AU Tel 44 01932 835000 Fax 44 01932 835001 British Sign Graphics Association Northgate Business Centre Northgate Newark Notts NG24 1EZ Tel 0845 338 3016 Email 176 Published in March 2015 by Vink Lighting Solutions Unit 8 Beldray Park Mount Pleasant Bilston West Midlands WV14 7NH Tel 01902 409205 Fax 01902 409378 While every reasonable effort is made to ensure that the information provided in this publication is accurate no guarantees for the currency or accuracy of information are made. It is provided without any representation or endorsement made and without warranty of any kind whether express or implied. Vink Lighting Solutions and Mike Hall Technical Services cannot be held responsible for any consequences based on action or inaction resulting from information contained herein. 178 Lighting for signs display provides practical support and advice on Internal and external lighting Optimising energy efficiency Accurate colour rendition 24-hour lighting solutions Maximising impact aesthetics Lighting for emphasis And more...