It took nearly six decades for electric light to finally replace petroleum lights as automotive lighting. The halogen light needed three more, which 20 once again replaced in the upper class with xenon light. But since the turn of the millennium, the development of headlights in cars has suddenly picked up speed.
Vehicle lighting has become a battle zone. Car manufacturers are battling for the best and brightest headlights. It all started about eight years ago with the duel between Lexus and Audi for the first use of LED headlights, the Zoff reached its preliminary climax last year with a bizarre struggle between Audi and BMW for the debut of the new type of laser light.
There are two interrelated reasons for the innovation trench warfare: On the one hand, cars are becoming more and more similar when it comes to propulsion, so that high-tech details are becoming more important for brand identity elsewhere. On the other hand, car lighting is no longer just about seeing, but also about being seen. Ever since BMW launched the characteristic corona rings on the headlights of its models at the beginning of the 2000er, light has been the calling card of a car. The transparent headlight housings have long since become small techno jewelery boxes, carefully designed daytime running lights advertise in the rear-view mirror of the person in front, and sizeable sums are called for light extras.
The premium manufacturers BMW and Audi are also the ones who currently want to use laser light to lead the field of innovators. The term is gaudy and the technology so advanced - the benefits are rather limited. Because the laser can only be used for a particularly high beam. The light cone reaches 600 meters - twice as far as most conventional LED high beams. Naturally, this only brings advantages on long, straight routes. And only on empty highways and country roads. In order not to dazzle other road users, the laser cone is swiveled to the side or completely switched off in the event of oncoming traffic. Nevertheless, almost five-digit surcharges are currently due for the technology.
That seems a lot, especially because the most advanced LED headlights in terms of high beam are not much worse. The new adaptive lights, such as those offered by Audi under the name Matrix-LED or Mercedes with the name "Multibeam", do not have a laser light source with endless high beam, but they still shine up to 500 meters. They are also more flexible when it comes to broadcasting the street. Brightness is provided by around two dozen light-emitting diodes, which are individually controlled, thus adapting the light cone to the given conditions. As a result, the cars are on the road with adaptive main-beam headlights - in the case of oncoming traffic or vehicles in front, the appropriate LEDs are simply switched off to prevent glare.
The particularly intelligent LED headlights are of course not cheap either. At Mercedes, for example, the multi-beam technology costs another 1.900 euro surcharge compared to conventional LED lights. The top light is therefore currently reserved for vehicles of the upper classes. But by the end of the year, Opel, the first volume manufacturer, wanted to offer a similar technology as an option in the new Astra. This also shows that the light hierarchy is currently in transition. "Today, the base is often halogen and the optional equipment xenon. In the future, xenon can certainly also conquer some standard equipment. Then the LED becomes a special feature, ”predicts Richard Lotholz, who is responsible for the automotive lighting division at the lamp manufacturer Osram.
In order to maintain technological leadership, the premium manufacturers are investing in even more advanced technology. Mercedes, for example, is already working with the lamp manufacturer Hella and the LED specialists from Osram on the so-called micro AFS headlight, which no longer consists of individual LEDs, but in which the diodes are cast into a chip in a highly compressed manner. One of the currently around 20 light points will then become more than 1.000. Lotholz calls this “car light HD”. The high-resolution spotlights open up completely new possibilities for staging light, because the lights could be used like projectors - and, for example, dazzling the approaching owner of a greeting message on the asphalt.
Designers also have high expectations for the so-called organic LED (OLED). The individual points of light disappear here; an entire area is lit up. OLEDs in the car are currently only available for reading lights or interior instruments. But on taillights, turn signals or on sheet metal body parts, the wafer-thin, transparent and superimposed lighting surfaces could open up completely new design worlds. The study “The Swarm”, which Audi presented at the IT trade fair CES 2013, shows how futuristic this can look. In this concept car, red flames flow over the body as rear lighting: when braking, they seem to be flying towards the person behind, when accelerating they appear to be moving away. The flashing lights dance as needed and shoot like comets in the turning direction. First OLED taillights 2016 should already come on the road, but not in such an extreme form.
However, OLED technology will not be suitable for headlights in the foreseeable future. But maybe that's not so bad, because headlights as we know them today could become obsolete in the long term. The directed, far-shining and visible light finally only needs a human driver. The computer chauffeurs of self-driving cars get along much better with invisible light. Infrared, lidar and laser observe the surroundings for them, not only in front of, but also behind and next to the car. Lighting would then only be needed as position light for other road users. The headlight eyes of our cars could then finally become a decorative ornament.
Author: Holger Holzer / SP-X