Sounds complicated, but I assure you, it isn't really all that complex. Just lots of heat in a very small space with special gases that suspend vaporized Tungsten for use with the Halogen Cycle. If that is not any simpler, try the wikipedia version of an explanation of Halogen bulbs. Anyway, this type of lighting capsule delivers massive amounts of light and heat in both consumption and light energy. Current reflector and projector technologies have allowed for exceptionally tight low beam pattern with virtually no additional lighting spill (spill is stray light emissions from either the light capsule and or the lamp housing).
Dipped beams or low beams are designed to illuminate the ground and markers while providing just the right amount of lighting to light up sign posts and other objects in front of the vehicle at speed. Reflection based lighting system employing Halogen bulbs create a very good and somewhat diffused dipped beam pattern. The diffused portion allows for the dipped beams to illuminate road markers and signs from a reasonable distance (normally about 80 to 100-feet in front of the vehicle, some further than others due to headlamp aiming). Reflector technology has been a common place in the United States since the beginning of the sealed and incandescent era. The fluting of the lens allows for the desired amount of diffused spill lighting to illuminate objects at a reasonable distance without blinding oncoming drivers and pedestrians.
Once Halogen cycle filament capsules enter the came in the late 70s to early 80s, the design of reflector housings and lenses changed to accommodate the increase in both light output and heat generation. The first Halogen capsules were sealed in a traditional sealed beam configuration to provide a near distortion free illumination of both ground and objects in the vehicle's path. Much whiter in color temperature than incandescent sealed beam lighting, it took the general public about ten years to get use the idea of Halogen sealed and free-form lighting technology. Ten years is a long time to adapt, but that said our eyes may not like the colder color temperature of Halogen versus standard incandescent lighting systems. Some food for thought.
To make matters worst, around 1996, Hella introduced projector light housings for both BMW and Audi. Smaller than free-form reflector housings and sealed beam Halogen lamps, projectors are able to deliver a tightly focused dipped beam without any significant diffusion and diffraction. This basically means that the light emitted from a projector lamp will deliver even coverage on the ground with very tight control of the amount of spill lighting markers and objects at a distance while preventing the typical diffused patterns that plague free-form reflector lamp designs. Both lamp housings have positive and negative areas such lighting pattern control, desired side and forward illumination, and other minor factors that can either be considered a true gain or loss to the intention of what shall be illuminated.
Then in late 1996, Infiniti Automotive released the J30 sedan with both low and high beam projectors citing that the system provides proper illumination without blinding oncoming drivers. While that statement is true to a varying degree, the projector governing the dipped beams couldn't illuminate the side markers and sign posts let alone objects from afar. The goal was to provide excellent forward illumination without blinding oncoming drivers and pedestrians, but in order to illuminate objects from afar, the projector beams would have to be calibrated for height. So illumination achieved and was a good marketing campaign on Infiniti's part if it weren't for the fact that vehicle was never a good seller. Still though it open door to projector headlamps for cars, trucks, utility vehicles, etc.
Advancing forward a bit, the first introduction to Xenon arc discharge lamps was not by the Germans or Japanese, but the Americans in the form of the 1997 Lincoln Coupe (don't remember the exact model). Using free-form reflector technology, the Lincoln was able to provide good ground illumination while having enough diffusion to light up objects and signs from afar. The system was supplied by Osram and the optics were developed by Hella and the combination of the two worked quite well. Delivering a color temperature of 4300K and throwing about 3000-lumens of light at 50-feet, the Lincoln Coupe made a statement in the American Automotive world that this type of technology is now available for those who want it. 3000-lumens at 50-feet is more light delivered than the typical 55-watt H7 Halogen thrown at the same 50-feet (600-lumens typically depending of optics used).
Afterward, the 1997 Mercedes E-class began offering an HID option throughout their model line in the US (since 1994 HID technology was available outside of the US due to lighter regulation) while other European and Japanese cars followed suite. BMW, Audi, and Porsche using projector lamps while others utilizing free-form diffused reflection, HID technology was primarily an added option that the vast majority didn't quite accept initially. Acura was the first company to incorporate the technology in both the mid and full-sized luxury sedans as standard equipment citing that it is a safety issue more than an option. Plus it basically gave the consumers an idea of the cost of such a lighting system when compared to Lexus, Mercedes, BMW, etc.(In 1998 the cost of an HID system centered around $1000 USD or more depending on the brand)
After the introduction to the tight lipped HID system (Hella, Phillips, Osram, and Bosch), it spawned aftermarket companies trying to imitate the system by offering alternatives by coating existing Halogen bulbs with a light-blue plasma coating to create the impression of an HID. This coating using is coupled to a richer xenon, argon, and Halogen mixer thus increasing the tungsten filament temperature thus increasing brightness and heat. So a 55-watt H7 bulb with a color temperature of 2800K would produce 600-lumens typically thrown about 50-feet, while a PIAA Hyper White with a color temp of 3800K of the same wattage consumption would produce about 1000-lumens thrown at the same distance (depending on optics used - this test is with a 1998 Mercedes E-class - free-form variable focus diffused reflection system). A 400-lumen increase in light output while consuming the same amount of energy is quite impressive. Normally to increase light output, more wattage would be required which increases energy consumption and heat output. In the case of the PIAA Hyper White series, energy consumption remains the same while heat output increases by about 10-percent(depends on the type of housing).
Many of us have purchased these kinds of bulbs for higher lumen output or looks(the HID look). I personally prefer the increase in output even though the heat output increases as well. That is not the typical mentality of the consumer that is since at that time, HID kits were around $1500.00 USD and only a small group was building them from OEM parts. The first generation kits were downright expensive and not very durable. The average life span of an original installation HID was about 3000-hours (+/-500-hours). That number is actually twice as long as the long-life Halogen globes offered by Sylvania. Did it justify that large number price tag going into HID, well for high-output and better appearance, I think the answer was "Yes". I actually waited about eight years for the prices to reach to the point that it was affordable. The first experience of an OE Retrofit was through Philips.
Philips offered an OE retrofit low-beam kit made completely in Germany (check out their website for more information) that I purchased online in 2008 through a group specializing in HID direct retrofits. These direct retrofits basically are full plug-in play type systems that do not require the consumer to completely take apart their existing wiring. A basic set of instructions and knowledge on how to wire things up and the lighting system is ready to go. It took me about two hours since my Mercedes using a special type of housing that required me to drill two hole to run the lamp's wires through to the ballast and electronic circuit. The end result is less power consumption and more lighting output with lower temperatures throughout the headlamp assembly. To give simple figures here, a typical 55-watt H7 type Halogen filament bulb consumes about 4.5-Amps each sustained at 12-VDC (typical is 1A at 12VDC should equal 12-watts). An HID system (two bulbs with ballast is a system) has to invert DC to AC in order for the ballast to generate the necessary starting voltage to power a Xenon Arc lamp. The startup voltage from the ballast to the bulb usually averages around 20kV at 2.0A (40000-watts) for a single second then slowly tapers off within a 20-seconds to a sustained 85-VAC at <.5A. The Xenon HID arc lamp is powered through AC from the ballast so the DC input at 12 to 14.5VDC during the startup phase can reach 8-Amps total. Once the HID system reaches full output though, the total system DC input averages around 3-amps sustained.
That is two lamps in the system averaging 3-amps versus two halogen globes each with a sustained current consumption of 4.5-amps (9-amps +/-1A total). Now all of these numbers may confuse you, but rest assured the easiest way to measure this is figure in the battery or alternator of a car and how much voltage and current is generated at any given time. My Mercedes's Alternator produces 14.5-VDC optimum and with an available 90-Amps/Hour of current. 9-Amps/hour to run my main headlights plus the fog beams add another 9-amps, and then factor in all of those power hungry engine electronics and accessories, there isn't much power generating juice to charge that car battery. These are things that I ask many that I know to take into consideration when putting in that very power hungry 2000-watt stereo system. Of course there is almost no way to consume 2000-watts of stereo power unless the system is either in the hands of a young person or a competition at which a power station supply may be used, but still though that amount of power generation required to supply such a system would be more than what a car's stock alternator is capable of.
Now I got the complex and confusing figures out of the way, one would think that HID technology would be the end of it right. I though so too until I started looking at how my solid-state lighting fixtures at home that I had put in a few years back can do, then started looking up the future of automotive lighting. Then I was able to work with Hella developing a very compact (I am Electro-Optics - Physics Researcher - Day Job), high-flux solid-state lighting solution. With their knowledge of both lighting and optics and my understanding of complex micro optics for high powered devices, Hella was able to develop and deploy the latest generation in automotive lighting while reducing power consumption, heat, and increasing lighting efficiency all in one very small package.
Enter the World of LED Automotive Lighting
LED technology is used just about everywhere. Before the lighting industry picking up steam in this department, we see LEDs as indicators, clock displays, little lights to light up our see through computer cases, and that sort of thing. As time went on, car companies started integrating Red LEDs into the center stop lamps for both intensity and fast response times. It was all good until the idea passed on to turn signal indicators, cabin lighting, side markers, and then eventually replacing all of those indicators with LEDs. It was all in the name of maintaing image, efficiency, and going green (in the automotive world, going green means also going hybrid). Becoming green requires many changes and in automotive applications means becoming highly efficient in reducing consumption and increasing overall operating efficiency.
Headlamps are by far the most inefficient consumers of electrical energy. Consuming large quantities of current, power, and voltage, these systems deliver only one third of their true potential while the rest is wasted in heat generation and optical efficiency. One-third is rather a small amount and many would say that is fine, but in a "Green" stand point of view though, this efficiency factor is rather pathetic. Even with the introduction of HID technology where a 35-watt AC arc lamp generates about 300% more light than say PIAA's 55-watt Hyper White Series Halogen Globe, the factors of optics efficiency and heat generation are still issues of concern. Not so much a heat generation factor since the power output is considerably lower than with a 55-watt power consumer. It kind of makes things more confusing since one would think that if the light is much brighter (tested), then it would make sense that the light being produced would be hotter (temperature). In the case of light, a Xenon Arc lamp transmits heat in the form of both gas and support frame whereas with Halogen, the glowing filament coupled with light transmission in a closed environment creates more heat.
In a simpler explanation, a 55-watt filament lamp will generate more heat than with a 35-watt lamp using the same technology. With gas discharge lamps however, the heat generation is mostly transmitted rather than conductive. And this is the easiest way to explain it. Hella, Bosch, Denso, and Osram have been working with many optics companies to develop and deploy a new method of providing excellent lighting with none of the drawbacks of current lighting technology in a very compact package. If household lighting and micro-torches can use solid-state lighting technology, why not automotive headlamp applications.
The first car to debut full integrated High and Low beams with full indicators was Audi with the new A8 and Hella stated the world's first solid-state lighting solution. Other automotive companies have large-ticket vehicles using solid-state lighting, but not the extent that incorporates all functions such as DRL, main dipped beams, high beams, and turn signal indicators. Granted, Lexus was the first car to introduce LED headlamps into the 2007 LS600H, but only in the form of angled dipped beams. High and fog beams were utilizing standard Halogen Capsules in free-form optics. The use of pure solid-state lighting technology in a rather compact and elegant package was developed for Audi by Hella.
Being a car person, I had the privilege to drive the new 2011 Audi A8L with the LED lighting package and I must say, from my experience in the high-powered optics industry, this is some of the best illumination of ground and air that I have seen in a long time. Ground illumination was beyond excellent to the degree that it has blown the former champion in this field. I speak of the Hella designed for Infiniti Q45 from 2003 till its demise in 2006. If you Google the Infiniti Q45, specify the year model between 03 to 06 and one will see what I am referring to. It consists of seven micro lenses arranged in a gatling gun barrel and using piped optics forming micro-projectors while using a single Xenon gas charged Arc lamp (HID). This arrangement produced a uniform low beam pattern covering all essential areas while providing more than enough diffused lighting to illuminate objects and sign posts at great distances. It is always impressive to see a 2005 or 2006 Infiniti Q45 coming up from behind you only to help illuminate the path in front of you. Hella did publish papers as to the design and tested light output efficiencies.
From a 35-watt HID lamp, the output illumination at 4300K color temperature was 4600-lumens at 50-feet or 3400-lumens at 120-feet. That would make this light nearly 80-percent efficient in real world terms while the virtual number is 90%. That is a far cry from 33-percent with traditional optics. Then factor in the size of the lenses coupled with the housing, compact in nature the Hella designed headlamp it wasn't but in terms of looks, this arrangement made the Infiniti Q45 look intimidating. When I come to think of it, if Hella is able to coax 4600-lumens at 50-feet using piped optics forming micro projectors in a single headlamp housing, why isn't other companies using the same idea to increase lighting efficiency and output without increasing heat generation. Hmmm. That may make an interesting conversation starter if it weren't so nerdy if many understand what I am getting at.
Any way with the LED lighting systems coming into play here, many are wondering what is next. Well without diving further detail into this, right now solid-state lighting is just making rounds here in the automotive world. Many companies will wait for the technology to mature to the level that can be successfully integrated as standard equipment without incurring massive costs. Until then, the Prius-5, Lexus, and Audi (their top models that is) will be the few companies out their with high-efficiency lighting systems to be put into their cars to make very "Green" statements.
Wait A Minute, You Have Explained Other Technologies, Why Not LED?
Solid-state lighting uses similar optics to the aforementioned Incandescent, Halogen Cycle, and HID technology. Optically speaking though, solid-state lighting and the former are very close together in technology. The only other aspect that LEDs have that the other technologies considered to be inefficient would be heat generation. Just to give mention here, the published specifications of the Audi A8s LED front lighting package are as follows. Total of High, Low, DRL, Parking, and Indicator LED System consumes a maximum of 38-Watts at 6-VDC. Using the standard 12VDC calculation, that would mean that the Audi A8's lighting package consumes 19-watts at 1A/Hour. The other figures were 3600-lumens measured at the dipped beam with a minimum distance of 60-feet while the high-beam figure up by 300-lumens same distance. The low beam consuming about 12-watts at 6VDC (white LED emitters are usually powered no more than 9VDC at 1A or 6VDC at 1.5A) which is the usual specs for the Cree LEDs used in the lamp array in the Audi.
As for the high-beams in the Audi A8's headlamp incorporates about six more watts or two Cree LEDs (I don't know which version of the XLamp series that is incorporated in the Audi LED headlamp) through special piped optics. These pipe optics basically serve two functions; reduced glare by the angle of the optic thus also cutting out the blue tint and the second is increase fill distance allowing for better illumination of objects from extreme distances. As such the total system consumption (single headlamp=system and not both headlamps) maximum of 38-watts at 6VDC or 19-watts at 12-VDC. I wish I snapped a picture of the headlamp unit when off and on just to illustrate what the system does and how effective the LEDs and optics are when compared to traditional high-flux illumination system.
LED headlamp systems are efficient, high-flux, and with the Hella designed optics, very well placed ground and diffused illumination. Like mentioned in the earlier paragraphs in regards to heat generation, LEDs do not suffer problems of luminous flux heat generation but from diode contact heat conduction. This type of heat generation is probably the most problematic since a great deal of heat sinking is required to cool. Hella designed the LED headlamp system with a complex heat pipe, liquid filled circulated, with air guides and micro radiators to cool the assembly to ensure reliable operation. All of this technology allows for the best possible illumination while allowing Audi to successfully change the image of the A8 and subsequently every other model in the company's lineup. I can say with certainty that the Audi A8 is the only vehicle currently with full solid-state lighting (except for fog lights - DOT regulation). Other car companies employ some method of solid-state lighting, but primarily for use with dipped beams and indicators.
Conclusions and Opinions of the Sort
Solid-state LEDs are the future of lighting technology be it home, commercial, marine, personal, automotive, etc. High flux, efficiency, and low heat generation is the most ideal attributes for designing commercial and automotive lighting systems since there is already an abundance of heat generation in a vehicle. HID systems are quite efficient with lower heat generation, but the complexity of the system itself means that specific xenon arc bulbs, ballasts, and relays are required. Once installed though, HID systems are reliable and trouble free. Halogen bulbs are the cheapest and with today's technological strides, the luminous flux output is approaching to the point where a 55-watt Halogen cycle Argon and Xenon gas filled bulb comes close to the 1200-lumens (through free-form reflector and diffused lens technology).
Each lighting technology have ad/disadvantages but each to ones own. Each incremental advancement in the field of optics and lighting means more energy savings over time with whatever implementation of the technology it is planned for. In the case of automotive lighting system, HID and LED lighting systems are the best method for energy savings since a good twenty percent of the energy consumption in a vehicle at any given time. Most of us who drive during the day and night do not realize how much electrical energy is consumed when driving. Now the alternator does provide additional power, but that only applies when the vehicle is in motion or at a high enough engine revolutions. Some food for thought when driving.
Hope this information helps in understanding those bluish white light.
Dipped beams or low beams are designed to illuminate the ground and markers while providing just the right amount of lighting to light up sign posts and other objects in front of the vehicle at speed. Reflection based lighting system employing Halogen bulbs create a very good and somewhat diffused dipped beam pattern. The diffused portion allows for the dipped beams to illuminate road markers and signs from a reasonable distance (normally about 80 to 100-feet in front of the vehicle, some further than others due to headlamp aiming). Reflector technology has been a common place in the United States since the beginning of the sealed and incandescent era. The fluting of the lens allows for the desired amount of diffused spill lighting to illuminate objects at a reasonable distance without blinding oncoming drivers and pedestrians.
Once Halogen cycle filament capsules enter the came in the late 70s to early 80s, the design of reflector housings and lenses changed to accommodate the increase in both light output and heat generation. The first Halogen capsules were sealed in a traditional sealed beam configuration to provide a near distortion free illumination of both ground and objects in the vehicle's path. Much whiter in color temperature than incandescent sealed beam lighting, it took the general public about ten years to get use the idea of Halogen sealed and free-form lighting technology. Ten years is a long time to adapt, but that said our eyes may not like the colder color temperature of Halogen versus standard incandescent lighting systems. Some food for thought.
To make matters worst, around 1996, Hella introduced projector light housings for both BMW and Audi. Smaller than free-form reflector housings and sealed beam Halogen lamps, projectors are able to deliver a tightly focused dipped beam without any significant diffusion and diffraction. This basically means that the light emitted from a projector lamp will deliver even coverage on the ground with very tight control of the amount of spill lighting markers and objects at a distance while preventing the typical diffused patterns that plague free-form reflector lamp designs. Both lamp housings have positive and negative areas such lighting pattern control, desired side and forward illumination, and other minor factors that can either be considered a true gain or loss to the intention of what shall be illuminated.
Then in late 1996, Infiniti Automotive released the J30 sedan with both low and high beam projectors citing that the system provides proper illumination without blinding oncoming drivers. While that statement is true to a varying degree, the projector governing the dipped beams couldn't illuminate the side markers and sign posts let alone objects from afar. The goal was to provide excellent forward illumination without blinding oncoming drivers and pedestrians, but in order to illuminate objects from afar, the projector beams would have to be calibrated for height. So illumination achieved and was a good marketing campaign on Infiniti's part if it weren't for the fact that vehicle was never a good seller. Still though it open door to projector headlamps for cars, trucks, utility vehicles, etc.
Advancing forward a bit, the first introduction to Xenon arc discharge lamps was not by the Germans or Japanese, but the Americans in the form of the 1997 Lincoln Coupe (don't remember the exact model). Using free-form reflector technology, the Lincoln was able to provide good ground illumination while having enough diffusion to light up objects and signs from afar. The system was supplied by Osram and the optics were developed by Hella and the combination of the two worked quite well. Delivering a color temperature of 4300K and throwing about 3000-lumens of light at 50-feet, the Lincoln Coupe made a statement in the American Automotive world that this type of technology is now available for those who want it. 3000-lumens at 50-feet is more light delivered than the typical 55-watt H7 Halogen thrown at the same 50-feet (600-lumens typically depending of optics used).
Afterward, the 1997 Mercedes E-class began offering an HID option throughout their model line in the US (since 1994 HID technology was available outside of the US due to lighter regulation) while other European and Japanese cars followed suite. BMW, Audi, and Porsche using projector lamps while others utilizing free-form diffused reflection, HID technology was primarily an added option that the vast majority didn't quite accept initially. Acura was the first company to incorporate the technology in both the mid and full-sized luxury sedans as standard equipment citing that it is a safety issue more than an option. Plus it basically gave the consumers an idea of the cost of such a lighting system when compared to Lexus, Mercedes, BMW, etc.(In 1998 the cost of an HID system centered around $1000 USD or more depending on the brand)
After the introduction to the tight lipped HID system (Hella, Phillips, Osram, and Bosch), it spawned aftermarket companies trying to imitate the system by offering alternatives by coating existing Halogen bulbs with a light-blue plasma coating to create the impression of an HID. This coating using is coupled to a richer xenon, argon, and Halogen mixer thus increasing the tungsten filament temperature thus increasing brightness and heat. So a 55-watt H7 bulb with a color temperature of 2800K would produce 600-lumens typically thrown about 50-feet, while a PIAA Hyper White with a color temp of 3800K of the same wattage consumption would produce about 1000-lumens thrown at the same distance (depending on optics used - this test is with a 1998 Mercedes E-class - free-form variable focus diffused reflection system). A 400-lumen increase in light output while consuming the same amount of energy is quite impressive. Normally to increase light output, more wattage would be required which increases energy consumption and heat output. In the case of the PIAA Hyper White series, energy consumption remains the same while heat output increases by about 10-percent(depends on the type of housing).
Many of us have purchased these kinds of bulbs for higher lumen output or looks(the HID look). I personally prefer the increase in output even though the heat output increases as well. That is not the typical mentality of the consumer that is since at that time, HID kits were around $1500.00 USD and only a small group was building them from OEM parts. The first generation kits were downright expensive and not very durable. The average life span of an original installation HID was about 3000-hours (+/-500-hours). That number is actually twice as long as the long-life Halogen globes offered by Sylvania. Did it justify that large number price tag going into HID, well for high-output and better appearance, I think the answer was "Yes". I actually waited about eight years for the prices to reach to the point that it was affordable. The first experience of an OE Retrofit was through Philips.
Philips offered an OE retrofit low-beam kit made completely in Germany (check out their website for more information) that I purchased online in 2008 through a group specializing in HID direct retrofits. These direct retrofits basically are full plug-in play type systems that do not require the consumer to completely take apart their existing wiring. A basic set of instructions and knowledge on how to wire things up and the lighting system is ready to go. It took me about two hours since my Mercedes using a special type of housing that required me to drill two hole to run the lamp's wires through to the ballast and electronic circuit. The end result is less power consumption and more lighting output with lower temperatures throughout the headlamp assembly. To give simple figures here, a typical 55-watt H7 type Halogen filament bulb consumes about 4.5-Amps each sustained at 12-VDC (typical is 1A at 12VDC should equal 12-watts). An HID system (two bulbs with ballast is a system) has to invert DC to AC in order for the ballast to generate the necessary starting voltage to power a Xenon Arc lamp. The startup voltage from the ballast to the bulb usually averages around 20kV at 2.0A (40000-watts) for a single second then slowly tapers off within a 20-seconds to a sustained 85-VAC at <.5A. The Xenon HID arc lamp is powered through AC from the ballast so the DC input at 12 to 14.5VDC during the startup phase can reach 8-Amps total. Once the HID system reaches full output though, the total system DC input averages around 3-amps sustained.
That is two lamps in the system averaging 3-amps versus two halogen globes each with a sustained current consumption of 4.5-amps (9-amps +/-1A total). Now all of these numbers may confuse you, but rest assured the easiest way to measure this is figure in the battery or alternator of a car and how much voltage and current is generated at any given time. My Mercedes's Alternator produces 14.5-VDC optimum and with an available 90-Amps/Hour of current. 9-Amps/hour to run my main headlights plus the fog beams add another 9-amps, and then factor in all of those power hungry engine electronics and accessories, there isn't much power generating juice to charge that car battery. These are things that I ask many that I know to take into consideration when putting in that very power hungry 2000-watt stereo system. Of course there is almost no way to consume 2000-watts of stereo power unless the system is either in the hands of a young person or a competition at which a power station supply may be used, but still though that amount of power generation required to supply such a system would be more than what a car's stock alternator is capable of.
Now I got the complex and confusing figures out of the way, one would think that HID technology would be the end of it right. I though so too until I started looking at how my solid-state lighting fixtures at home that I had put in a few years back can do, then started looking up the future of automotive lighting. Then I was able to work with Hella developing a very compact (I am Electro-Optics - Physics Researcher - Day Job), high-flux solid-state lighting solution. With their knowledge of both lighting and optics and my understanding of complex micro optics for high powered devices, Hella was able to develop and deploy the latest generation in automotive lighting while reducing power consumption, heat, and increasing lighting efficiency all in one very small package.
Enter the World of LED Automotive Lighting
LED technology is used just about everywhere. Before the lighting industry picking up steam in this department, we see LEDs as indicators, clock displays, little lights to light up our see through computer cases, and that sort of thing. As time went on, car companies started integrating Red LEDs into the center stop lamps for both intensity and fast response times. It was all good until the idea passed on to turn signal indicators, cabin lighting, side markers, and then eventually replacing all of those indicators with LEDs. It was all in the name of maintaing image, efficiency, and going green (in the automotive world, going green means also going hybrid). Becoming green requires many changes and in automotive applications means becoming highly efficient in reducing consumption and increasing overall operating efficiency.
Headlamps are by far the most inefficient consumers of electrical energy. Consuming large quantities of current, power, and voltage, these systems deliver only one third of their true potential while the rest is wasted in heat generation and optical efficiency. One-third is rather a small amount and many would say that is fine, but in a "Green" stand point of view though, this efficiency factor is rather pathetic. Even with the introduction of HID technology where a 35-watt AC arc lamp generates about 300% more light than say PIAA's 55-watt Hyper White Series Halogen Globe, the factors of optics efficiency and heat generation are still issues of concern. Not so much a heat generation factor since the power output is considerably lower than with a 55-watt power consumer. It kind of makes things more confusing since one would think that if the light is much brighter (tested), then it would make sense that the light being produced would be hotter (temperature). In the case of light, a Xenon Arc lamp transmits heat in the form of both gas and support frame whereas with Halogen, the glowing filament coupled with light transmission in a closed environment creates more heat.
In a simpler explanation, a 55-watt filament lamp will generate more heat than with a 35-watt lamp using the same technology. With gas discharge lamps however, the heat generation is mostly transmitted rather than conductive. And this is the easiest way to explain it. Hella, Bosch, Denso, and Osram have been working with many optics companies to develop and deploy a new method of providing excellent lighting with none of the drawbacks of current lighting technology in a very compact package. If household lighting and micro-torches can use solid-state lighting technology, why not automotive headlamp applications.
The first car to debut full integrated High and Low beams with full indicators was Audi with the new A8 and Hella stated the world's first solid-state lighting solution. Other automotive companies have large-ticket vehicles using solid-state lighting, but not the extent that incorporates all functions such as DRL, main dipped beams, high beams, and turn signal indicators. Granted, Lexus was the first car to introduce LED headlamps into the 2007 LS600H, but only in the form of angled dipped beams. High and fog beams were utilizing standard Halogen Capsules in free-form optics. The use of pure solid-state lighting technology in a rather compact and elegant package was developed for Audi by Hella.
Being a car person, I had the privilege to drive the new 2011 Audi A8L with the LED lighting package and I must say, from my experience in the high-powered optics industry, this is some of the best illumination of ground and air that I have seen in a long time. Ground illumination was beyond excellent to the degree that it has blown the former champion in this field. I speak of the Hella designed for Infiniti Q45 from 2003 till its demise in 2006. If you Google the Infiniti Q45, specify the year model between 03 to 06 and one will see what I am referring to. It consists of seven micro lenses arranged in a gatling gun barrel and using piped optics forming micro-projectors while using a single Xenon gas charged Arc lamp (HID). This arrangement produced a uniform low beam pattern covering all essential areas while providing more than enough diffused lighting to illuminate objects and sign posts at great distances. It is always impressive to see a 2005 or 2006 Infiniti Q45 coming up from behind you only to help illuminate the path in front of you. Hella did publish papers as to the design and tested light output efficiencies.
From a 35-watt HID lamp, the output illumination at 4300K color temperature was 4600-lumens at 50-feet or 3400-lumens at 120-feet. That would make this light nearly 80-percent efficient in real world terms while the virtual number is 90%. That is a far cry from 33-percent with traditional optics. Then factor in the size of the lenses coupled with the housing, compact in nature the Hella designed headlamp it wasn't but in terms of looks, this arrangement made the Infiniti Q45 look intimidating. When I come to think of it, if Hella is able to coax 4600-lumens at 50-feet using piped optics forming micro projectors in a single headlamp housing, why isn't other companies using the same idea to increase lighting efficiency and output without increasing heat generation. Hmmm. That may make an interesting conversation starter if it weren't so nerdy if many understand what I am getting at.
Any way with the LED lighting systems coming into play here, many are wondering what is next. Well without diving further detail into this, right now solid-state lighting is just making rounds here in the automotive world. Many companies will wait for the technology to mature to the level that can be successfully integrated as standard equipment without incurring massive costs. Until then, the Prius-5, Lexus, and Audi (their top models that is) will be the few companies out their with high-efficiency lighting systems to be put into their cars to make very "Green" statements.
Wait A Minute, You Have Explained Other Technologies, Why Not LED?
Solid-state lighting uses similar optics to the aforementioned Incandescent, Halogen Cycle, and HID technology. Optically speaking though, solid-state lighting and the former are very close together in technology. The only other aspect that LEDs have that the other technologies considered to be inefficient would be heat generation. Just to give mention here, the published specifications of the Audi A8s LED front lighting package are as follows. Total of High, Low, DRL, Parking, and Indicator LED System consumes a maximum of 38-Watts at 6-VDC. Using the standard 12VDC calculation, that would mean that the Audi A8's lighting package consumes 19-watts at 1A/Hour. The other figures were 3600-lumens measured at the dipped beam with a minimum distance of 60-feet while the high-beam figure up by 300-lumens same distance. The low beam consuming about 12-watts at 6VDC (white LED emitters are usually powered no more than 9VDC at 1A or 6VDC at 1.5A) which is the usual specs for the Cree LEDs used in the lamp array in the Audi.
As for the high-beams in the Audi A8's headlamp incorporates about six more watts or two Cree LEDs (I don't know which version of the XLamp series that is incorporated in the Audi LED headlamp) through special piped optics. These pipe optics basically serve two functions; reduced glare by the angle of the optic thus also cutting out the blue tint and the second is increase fill distance allowing for better illumination of objects from extreme distances. As such the total system consumption (single headlamp=system and not both headlamps) maximum of 38-watts at 6VDC or 19-watts at 12-VDC. I wish I snapped a picture of the headlamp unit when off and on just to illustrate what the system does and how effective the LEDs and optics are when compared to traditional high-flux illumination system.
LED headlamp systems are efficient, high-flux, and with the Hella designed optics, very well placed ground and diffused illumination. Like mentioned in the earlier paragraphs in regards to heat generation, LEDs do not suffer problems of luminous flux heat generation but from diode contact heat conduction. This type of heat generation is probably the most problematic since a great deal of heat sinking is required to cool. Hella designed the LED headlamp system with a complex heat pipe, liquid filled circulated, with air guides and micro radiators to cool the assembly to ensure reliable operation. All of this technology allows for the best possible illumination while allowing Audi to successfully change the image of the A8 and subsequently every other model in the company's lineup. I can say with certainty that the Audi A8 is the only vehicle currently with full solid-state lighting (except for fog lights - DOT regulation). Other car companies employ some method of solid-state lighting, but primarily for use with dipped beams and indicators.
Conclusions and Opinions of the Sort
Solid-state LEDs are the future of lighting technology be it home, commercial, marine, personal, automotive, etc. High flux, efficiency, and low heat generation is the most ideal attributes for designing commercial and automotive lighting systems since there is already an abundance of heat generation in a vehicle. HID systems are quite efficient with lower heat generation, but the complexity of the system itself means that specific xenon arc bulbs, ballasts, and relays are required. Once installed though, HID systems are reliable and trouble free. Halogen bulbs are the cheapest and with today's technological strides, the luminous flux output is approaching to the point where a 55-watt Halogen cycle Argon and Xenon gas filled bulb comes close to the 1200-lumens (through free-form reflector and diffused lens technology).
Each lighting technology have ad/disadvantages but each to ones own. Each incremental advancement in the field of optics and lighting means more energy savings over time with whatever implementation of the technology it is planned for. In the case of automotive lighting system, HID and LED lighting systems are the best method for energy savings since a good twenty percent of the energy consumption in a vehicle at any given time. Most of us who drive during the day and night do not realize how much electrical energy is consumed when driving. Now the alternator does provide additional power, but that only applies when the vehicle is in motion or at a high enough engine revolutions. Some food for thought when driving.
Hope this information helps in understanding those bluish white light.
0 comments:
Post a Comment