LED WHAT S IMPORTANT?

Transcription

1 LED WHAT S IMPORTANT?

2 02 03 IN TR O We come across LEDs in many areas of our lives today. Whether on a smartphone, LED TV or interior lighting: Almost everyone uses this modern technology nearly every day whether they are aware or not. For vehicle lighting as well, the use of LEDs has played a large role for years and its significance will increase even more in the future. The reasons for this are obvious, because LED technology provides many advantages, such as exceptionally high energy efficiency, a long service life, low maintenance and homogeneous, daylightlike roadway and workspace lighting. Customers continue to have a wide variety of different questions on the topic of LEDs, whether they relate to the technical background or specific applications. For many years, HELLA has been a forerunner and technology leader in always developing new, innovative LED headlamp applications. As a result, we have amassed considerable expertise in this area, which we would like to share with you in this brochure. For sharing this information, we have compiled some of the most frequently asked questions and provided expert answers to them prepared in an informative, entertaining and clear way. We hope you have fun reading! Your HELLA team

3 INDEX WHAT IS LED? 04 _ IS EVERY LED THE SAME? 06 _ DO LEDS GENERATE HEAT? 08 _ DO LEDS ALSO WORK ON THEIR OWN? 10 _ HOW DO YOU ACHIEVE THE BEST POSSIBLE LIGHT OUTPUT USING LEDS? 12 _ DO ALL LEDS HAVE THE SAME LIGHT COLOUR? 14 _ LUX, LUMENS, CANDELA WHAT ARE THE DIFFERENCES? 16 _ IS THE LIGHT DISTRIBUTION FOR LEDS MORE HOMOGENEOUS THAN FOR HALOGEN HEADLAMPS? 18 _ HOW LONG DO LEDS LAST? 20 _ HOW ENERGY EFFICIENT ARE LEDS? 22 _ WHO CAN REALLY BENEFIT FROM LEDS? 24 _ IS IT EASY TO UPGRADE FROM HALOGENS TO LED? 26 _ HOW CAN LED HEADLAMPS BE ADJUSTED CORRECTLY? 28 _ HAS LED TECHNOLOGY REACHED THE PEAK OF ITS DEVELOPMENT? 30 _ THE HELLA LED WORLD 32 _

4 04 05 WHAT IS LED?

5 Lenticular top end Cylindrical body Semiconductor crystal Reflector Anode Cathode LED (LIGHT EMITTING DIODE) An LED is a light-emitting semiconductor component part that gives off visible light, infrared radiation or ultraviolet radiation as soon as current flows through the diode. Here, the semi-conductor material used is critical for determining the wavelength. An LED consists mainly of an anode, cathode, semiconductor crystal, bond wire and housing. For most LEDs, the cathode also acts as the reflector. The bond wire connects the crystal to the diode. The solder joint forms one of the two electrical connections for the crystal. At the same time, it absorbs the dissipated heat that develops because the semiconductor crystal can convert only a portion of the electrical power into light. LEDs are operated in a temperature-dependent operating point which has to be determined/configured precisely. Direct operation of an LED on a voltage source is not possible without a series resistor. Today, LEDs are used in many areas: smartphone displays, LED TVs, room lighting, and even operating room equipment. Small LEDs have long since become an integral part of everyday life. This is especially true in the area of vehicle lighting. In addition to being used in main headlamps, worklights, high beams and auxiliary headlamps, daytime running lights and rear (combination) lamps, LEDs are also used for equipment such as side marker lights and signal lights. This covers a wide application spectrum that consists of more than just classic passenger car lighting. It also includes special applications, such as trucks, trailers, agriculture and emergency vehicles, just to name a few examples. Cathode Chip Heat shield with reflector Housing Bond wire Protective diode Silicone or epoxy resin coating Anode

6 06 07 IS EVERY LED THE SAME?

7 NO There are absolutely differences between LEDs, particularly in terms of quality, lifetime and power. HELLA uses very high-quality and durable LEDs that meet the special requirements for the technically demanding vehicle lighting. This requires using a strict selection process starting in LED production. Only LEDs that fall into a narrowly structured and pre-defined target range in terms of light colour and colour temperature are permitted for use in our products. When selecting the LEDs, the intended use also plays a role. LEDs used in our high-performance headlamps typically have even more stringent requirements than those for LEDs that are used in side marker lights or other signal lights for example. For our main headlamps, worklights and auxiliary headlamps, there are particularly strict specifications in terms of illumination and luminosity which can be met only by carefully selected high-performance LEDs with constant quality characteristics. The light colour of the individual LEDs should always be nearly identical and be similar to daylight to ensure the uniformity of all headlamps. Only the perfect interaction between LEDs, headlamp and reflector technologies, and the heat management lead to a truly impressive lighting result. As a technology leader, HELLA's experience and development expertise focuses on innovative LED technologies that get the best out of the LEDs, ensuring an optimal light pattern and long service life. Commercially available LED products frequently cannot be compared to each other on a 1:1 basis due to these quality characteristics. Very inexpensive products, even if they might look similar on the outside, can exhibit poor quality, weak colours and reduced service life over the duration of use. Therefore, put your trust in HELLA LED quality products everytime!

8 08 09 DO LEDS GENERATE HEAT?

9 EVEN LEDS GENERATE OPERATING HEAT. However, the amount is far less than the heat that would be generated by a comparable incandescent bulb. LEDs have high energy efficiency as a result. Unlike conventional light sources, they convert a majority of the supplied energy into light. As an example: A 60 watt bulb has an illuminating power of approximately 600 lumens. A current LED lamp that generates 600 lumens, on the other hand, only consumes approximately 8 watts. LED headlamps only radiate a small amount of UV and infrared light. Therefore, unlike halogen headlamps, they will not become hot at the points where light is emitted. But an LED headlamp can still generate heat in the housing. However, the respective headlamp's electronics are the true culprit in this case, but they are necessary to enable an optimum lighting result. Very good thermal management ensures reliable, targeted dissipation of the heat generated by the electronics. HELLA is a recognised expert in this area. This is because optimum temperature management not only ensures proper headlamp functionality, it also significantly extends the service life. One example is the HELLA Ultra Beam Gen. II worklight. The circuit board installed in the housing includes both the LEDs and the electronics components. The heat generated by the electronics can reach up to 150 C under extreme conditions but, unlike the case for halogen headlamps, it is dissipated towards the rear. Controlled heat dissipation is possible by bonding the circuit board to the aluminum housing and by using a special heat conducting film. Thermal simulations indicate the temperature zones and heat distribution on the housing. The aluminum body ensures that the heat dissipates quickly.

10 10 11 DO LEDS ALSO WORK ON THEIR OWN?

11 HELLA Matrix HD84 headlamp Primary optics - Three-step precision optics system NO BECAUSE LEDS HAVE TO BE ACTIVATED. Corresponding electronics are required for this. They should be precisely matched to the respective application and additional operating conditions. In relation to vehicle headlamps, for example, this means that various control electronics are used in different vehicle models. The programming here is accurately coordinated to the interaction between the headlamp and vehicle. That is also one of the main advantages of original HELLA products because we have years of development experience in this area where numerous OE manufacturers have placed their trust. One example of a state-of-the-art LED headlamp with innovative control electronics is the new HELLA Matrix HD84 headlamp in the Mercedes e-class limousine. This latest-generation LED headlamp combines the many advantages of LEDs in an advanced way with state-of-the-art control technologies. This allows the light distribution to be adapted automatically to nearly any traffic situation at lightning speed and with great precision. The result: previously unheard-of glare-free light distribution and a light range that also adapts to the respective driving situation like city, rural road or highway and to weather conditions.

12 12 13 HOW DO YOU ACHIEVE THE BEST POSSIBLE LIGHT OUTPUT WITH LEDS?

13 Heat sink Electronics Reflector This requires complex interaction between various components. This is not just about generating the highest possible light output. It is just as important to also distribute the generated light homogenously to the respective workspace. Simply combining the largest number of LEDs is not enough to achieve this however, because this ultimately only leads to disproportionately high energy consumption. For the best-possible light result, the quality and quantity of the LEDs are not the only aspects that play a role. The prismatic optics in use, the control electronics and, last but not least, optimum thermal management are just as important. While the LEDs generate the actual light output, the prismatic optics ensure that the light is distributed to the desired work area as a combined beam or as intended. In turn, control electronics serve as the "brain". Only they can be used to implement innovative light functions such as glare-free high-beam lights or adaptive cornering lights. Sophisticated thermal management becomes more important as the electronics become more advanced. This is necessary to dissipate the generated heat and ensure a long service life for the LEDs as a result. As one of the pioneers in the area of LED headlamp development, HELLA has strong, longstanding expertise in development and production in every area: LEDs, prismatic optics, control electronics and thermal management solutions. As a result, all of our LED headlamps form an overall package that is perfectly tuned for the light results that best suit the required situation.

14 14 15 DO ALL LEDS HAVE THE SAME COLOUR?

15 LEDs can also be used to achieve a variety of light colours. Light colour in this context does not mean coloured lighting from sources such as red, green or blue LEDs. Instead it refers to the actual "appearance" of the light generated by white LEDs. The light colour, also called colour temperature, is generally specified in kelvin. Typically, there are roughly three areas of colour perception: COLOUR PERCEPTION Warm white < 3300 K Neutral white K Daylight white (also called cold white) > 5000 K COLOUR TEMPERATURE AND WHY IS LIGHT COLOUR IMPORTANT? LEDs can be used to cover the complete spectrum from warm white to daylight white. The light colour similar to daylight is particularly significant in the vehicle lighting area. Studies have shown that this light colour ensures a significantly improved ability to recognise the roadway and objects. Furthermore, light similar to daylight can be used effectively to reduce driver fatigue that occurs frequently when driving at night. This, in turn, significantly increases road safety. In the area of light research, HELLA is among the absolute experts. And this is exactly why numerous vehicle manufacturers around the world rely on our light technology solutions. In the LEDs used for our high-performance LED headlamps, we create strict quality scales relating to light colour as well as brightness starting in the selection process. Both parameters have to be within a strictly defined tolerance area. This is the only way to ensure consistently high and uniform light quality for all products in terms of brightness, light colour and additional parameters. By the way: only white, high-quality LEDs are used for our LED signal lights, such as position or side marker lights, for example. The various light signal colours, such as red or yellow, are achieved using coloured cover lenses in this case. It is important to note, however, that the colour perception is subjective and completely independent of the actual, measurable kelvin values. Accordingly, colour is a general impression and humans are not capable of delineating the spectral composition of the light without technical resources. This means it is practically impossible to get a feel for how other people perceive colour in comparison to ourselves. Even for a single individual, personal colour perception is subject to daily fluctuations.

16 16 17 LUX LUMENS CANDELAS WHAT ARE THE DIFFERENCES?

17 These three terms are often confused. However, they deal with various factors relating to lighting technology. We would like to bring a few things to light, as it were: LUMEN (lm) A lumen is the unit of the luminous flux and describes the overall light that is emitted by a light source such as an LED headlamp. However, the lumen value does not provide a statement on how the light is distributed in the room. CANDELA (cd) Candela is the unit that describes the strength of the light emission that is sent from a light source in a specific direction. Candela, like a lumen, is also a transmission value. Traditionally, 1 candela corresponds to the luminous intensity of a household candle. A candela is also used as the unit of luminous intensity, i.e. of the subjective brightness perceived by the human eye from an illuminated surface. This also describes what is called the "glare". LUX (lx) Lux, in turn, is the unit used to measure illuminance. The lux value specifies the light emanating from the light source that strikes a specific surface. Unlike lumens and candelas, lux is a "receiver value". This means that it measures the amount of light arriving in a specified area. This is crucial in achieving optimum working conditions. A lumen value is frequently specified for main headlamps and worklights. As an example, our Ultra Beam LED Gen. II worklight achieves a powerful measured output of 4000 lumens. Here, the difference between measured and calculated lumens is enormously important. Only measured lumens yield the correct, precise value. Calculated lumens merely provide a theoretical value. Calculated lumens do NOT provide useful information and are always higher than the measured lumens because energy losses from heat and light losses through the reflector and cover lens are not taken into account. HELLA only specifies real measured lumen values for this reason! When comparing or purchasing headlamps, always check if the lumen specifications are a measured or calculated value! Another value is relevant for auxiliary (high-beam) headlamps. This is the reference number (ref.). This value tells you the maximum luminous intensity the headlamp can produce. The reference number enables you to see at a glance how powerful a headlamp is. The reference number is obtained by converting the maximum luminous intensity in candelas. It is a dimensionless number so it has no associated unit of measurement. Please note the national regulations related to the reference value that apply in your country and check whether you are subject to the ECE Regulation in force since In some countries, a total reference value (the sum of the reference values of all high-beam headlamps on the vehicle) exceeding 100 is not permitted.

18 18 19 IS THE LIGHT DISTRIBUTION FOR LEDS MORE HOMOGENEOUS THAN FOR HALOGEN HEADLAMPS?

19 YES, THE LIGHT DISTRIBUTION FOR LED HEADLAMPS IS GENERALLY MORE HOMOGENOUS THAN FOR OTHER COMPARABLE LIGHT SOURCES. This enables uniform illumination of many areas. This is a significant advantage when performing field work with worklights in the dark because many of the tasks required in this type of work are carried out in winter. Uniform illumination is also applicable to modern LED headlamps in passenger vehicles. Optimum light bundling allows users to generate homogenous illumination of well-defined areas. Nevertheless, LEDs should not be viewed in isolation because there are other factors that are crucial to illumination. The lens and reflector used in the headlamp, as well as the alignment of the headlamp itself, also play a role. A high-quality reflector can achieve optimum bundling and control of the light, while the alignment determines the light's angle. State-of-the-art LED applications specially designed for beamsetters are used to align and adjust LED headlamps on the vehicle. The Hella Gutmann Solutions brand from Hella boasts considerable expertise in this area. Worklights are aligned at the recommend tilt angle right on the vehicle. The individual requirements of the respective vehicle and the application situation (including field work, manoeuvring, illumination at close and long range, etc.) have to be taken into account in this process. NOTE: Our free HELLA ELIVER tool lets you compare illumination from halogen, xenon and LED auxiliary and worklights simply visit and try it yourself!

20 20 21 HOW LONG DO LEDS LAST?

21 30,000 25,000 20,000 15,000 10,000 5,000 Light bulb Halogen Energy-saving lamp Fluorescent lamp LED This depiction is only intended to be a schematic representation. The true service life may deviate from these values. LEDs have an extremely long service life that can often exceed the life of the vehicle. This is one of the most significant advantages of LEDs compared to conventional light sources such as halogen lamps. While these light sources may fail during the life of a vehicle and then require replacement or purchase of a new light source, LEDs are maintenance-free. In addition to low energy consumption resulting from high energy efficiency, LEDs offer substantial cost advantages over the medium term due to their long service life. However, even the best LEDs cannot be spared from harsh environmental influences. As a result, even LEDs in headlamps can fail in extremely unfavourable circumstances. These cannot be replaced individually at present. Unfortunately, such scenarios require complete replacement of the headlamp. Luckily, this an extremely rare occurrence when you use HELLA headlamps. Another crucial factor for a long service life is optimum thermal management of the respective headlamp (also see page 8), which prevents LEDs from overheating. The innovative HELLA thermal management solutions used in HELLA headlamps make a substantial contribution toward a long LED and headlamp life.

22 22 23 LED INPUT OUTPUT HOW ENERGY- EFFICIENT ARE LEDS? HALOGEN

23 In addition to their service life (see also page 20), high energy efficiency is one of the main advantages of LED technology. LEDs are like the top athletes of the light source world. Though they consume little energy, they achieve a high maximum output and are among the top performers. Low power consumption saves energy and reduces costs. Though LEDs are currently a bit more expensive than other lights, purchasing them certainly pays off over the medium term due to the associated lower operating costs. The lower power consumption of LEDs has another secondary effect that should not be underestimated. It contributes a great deal to the conservation of resources. Even on forklifts with small batteries, the use of LEDS is a proven means of conserving battery capacity and extending operating times as a result. Energy-efficient vehicle lighting is already an important topic and will continue to increase in importance. Due to an increasing number of electric vehicles, conserving resources used in vehicles has become particularly important. As a result, the use of highly efficient LED technology is almost inevitable.

24 24 25 WHO CAN REALLY BENEFIT FROM LEDS?

25 EVERYONE CAN BENEFIT FROM LEDS! Why is this the case? The following LED advantages are crucial: durability, energy efficiency, cost efficiency, homogenous illumination in all areas, light colour and luminous intensity like daylight. Of course, professional users in particular benefit from LEDs. This includes farmers, who rely on optimum long and close-range illumination, and fleet operators, who work long hours and use LEDs to achieve substantial reductions in cost through reduced energy and maintenance expenses as well as shorter downtimes and outage times. Customised design freedom yields another advantage that has not yet been mentioned, and which many users appreciate. The small size of the LEDs and sharp light definition give vehicle and product designers the opportunity to create very special designs. LEDs are both cost-effective and stylish! As a result, every HELLA LED product is a technical, visual and functional highlight, and adds a special finishing touch to every vehicle.

26 26 27 IS IT EASY TO UPGRADE FROM HALOGENS TO LED?

27 HALOGEN LED AND WHAT ARE THE CONSIDERATIONS? In most cases, it is possible and makes sense to convert from halogen lamps to new, highly efficient LED technology! Replacing the lamps themselves is relatively cost-effective and can be done in just a few steps. Nevertheless, additional factors must be taken into account before, during and after the conversion, depending on the application situation. LEDs usually require separate drivers that also have to be installed. Worklights must be oriented at the correct tilt angle, which must be configured separately for each vehicle. Only a correctly adjusted worklight enables optimum illumination of the work area. Consider the following factors to ensure that you benefit from all advantages of an LED conversion. Refer to various HELLA media for additional assistance with respect to LEDs. A corresponding overview is provided on page 32. NOTE: The energy consumption (watts) of LED lights is significantly lower compared to a bulb version. This may require adjusting the peripherals for the failure monitor after upgrading for operation on some traction vehicles. Since monitoring the direction indicator is required by law in accordance with ECE R48, we recommend operating these lamps only in conjunction with the HELLA indicator control unit.

28 28 29 HOW CAN LED HEADLAMPS BE ADJUSTED CORRECTLY?

29 -5º -4º -3º -2º -1º 0º +1º +2º +3º +4º +5º Zero line As an example using the Audi A8 headlamp with matrix high-beam assistant: The square marking indicates the correct position of the vertical cut-off line on the zero line. If there is any deviation, the correction value (distance to zero line) is simply transferred to the control unit via mega macs. Vehicle-specific configuration of LED headlamps differs from configuration of conventional headlamps and requires some new configuration methods because the light field on LED headlamps consists of several light sources (LED modules). This necessitates the use of special precision measurement devices. Modern beamsetters are now capable of correctly assessing current halogen, xenon and LED headlamp systems with respect to the light distribution of all low beams, high-beam headlamps and the vertical cut-off line. The devices are also equipped with technical functions, including a broadband viewer with integrated crosshair, a digital luxmeter, integrated laser positioning tool and high-precision test screen scaling. Fine, vertical scaling enables users to read off values precisely to within 0.1, which also meets the requirements for testing and calibrating various high-beam assistants. These high-beam assistants must be tested, assessed and calibrated separately (depending on the manufacturer), but it is no longer possible to do this mechanically in some cases. This requires interaction between the beamsetter and a corresponding diagnostic unit, such as between a SEG IV beamsetter and a diagnostic unit from the Hella Gutmann Solutions mega macs series. These devices work together and enable the display of complex systems such as the LED matrix high beam in the current Audi A8. Increasingly, the trend in beamsetters is moving towards a digital implementation, such as the camera-based SEG V beamsetter from Hella Gutmann. It features a sophisticated user interface and a vehicle model list inside the system. Stored algorithms help users avoid incorrect interpretations and settings for different headlamps. Direction arrows on the beamsetter's control panel indicate any necessary adjustment changes. The speed of image processing in these modern devices is so fast that each change is displayed while the headlamp adjusting screws are being turned. As soon as the corresponding light distribution has been set to the required tolerance limits, the displayed direction arrows in the beam setter turn green. Light adjustment has been successfully completed.

30 30 31

31 HAS LED TECHNOLOGY REACHED THE PEAK OF ITS DEVELOPMENT? No, of course not! It's just getting off the ground. Continuous vehicle lighting innovations from HELLA are yielding more and more options for the use of LEDs, with solutions that likely would not have occurred to anyone in this form until recently. One example is HELLA Matrix LED technology. This allows the driver to travel with (LED) high beams on continuously without risk of blinding oncoming traffic or any vehicles on the road ahead. Such a function is possible at a technical level by splitting the high beam into five reflectors, each with a chip containing 5 LEDs. For the first time ever, HELLA has now succeeded in operating every LED on the 5-segment chip individually, whereby a total of 25 LEDs per headlight can be operated on full power or dimmed as and when required. In this way, the light cone can be controlled to a tremendously precise degree without the need for any pivoting mechanism. The result is that a huge number of variations in light distribution can be achieved. Another feature of this lighting technology is the dynamic direction indicator, where the noticeable wiper effect plays a role in increasing safety. The innovative LED light carpet in the BMW 7 Series is another example of future-focused development. Press a button on the key and the light carpet beams from both sides of the car, conveniently guiding the driver to the vehicle. Specially designed micro-optics comprised of many minute microlenses are used to carefully direct the light onto the ground. LED development also shows exceptional progress in areas outside of vehicle lighting. OLED technology (OLED = organic light emitting diode) is expected to be used in an increasing number of applications in the years to come. OLEDs are light-emitting diodes made of organic, semi-conductive polymers. In simple terms, they enable production of an ultra-thin, flexible "light film". OLED displays do not use background illumination, so they consume less energy than LCDs. They are currently used in a variety of devices such as smartphones and LED TVs. The main challenge is to improve the lifetime of these diodes. As a result, OLEDs are primarily used in applications where displays are only in operation for short periods of time. Even in these areas, LED technology is undergoing continuous improvement. OLED technology might even be used in vehicles in the near future. THE FUTURE OF LED TECHNOLOGY LOOKS BRIGHT BOTH FOR DEVELOPERS AND FOR USERS!

32 32 33 THE HELLA Addlight mobile app Download our app from Google Play or itunes and learn all about the HELLA auxiliary headlamp range detailed and interactive, with loads of extra information and technical details. Worklights mobile app Let yourself be drawn into the interactive world of worklights and experience the variety of lighting technologies, exploded views and much more. Simply download the app from itunes or Google Play!

33 LED WORLD Truck website Clear and structured: Visit this site to learn about HELLA's extensive product portfolio and find out more about current topics related to trucks. Agriculture website Informative, compact, interactive. Here you will find all you need to know about the products and technologies for agricultural use. ELIVER the light comparison tool This online tool allows you to compare many HELLA worklights and beacons on the basis of their illumination in a realistic environment

34 34 35

35

36 HELLA KGaA Hueck & Co. Rixbecker Straße Lippstadt, Germany Tel.: Fax: Internet: HELLA KGaA Hueck & Co., Lippstadt 9Z J01168/KB/08.16/0.65 Printed in Germany Subject to technical and price modifications.