TÜV SÜD informs about laser lights, LEDs and matrix headlights
Automotive lighting has developed dynamically over recent years, with LEDs and lasers causing a sensation as new light sources. However, TÜV SÜD points out that in recent years progress has also presented itself in other aspects, the most important being glare-free high-beam headlights; these ensure better visibility, and thus higher safety. The wider design options offered by LEDs have further impacted on lighting development.
There can be few motorists that are unfamiliar with halogen and xenon headlights. “While LEDs are the light of the future, these two types of headlights are still very far from obsolete”, says Philipp Schreiber, TÜV SÜD. “However, halogen headlights will continue to be the choice for all those cases in which costs are more important than design.” Very important in the expert’s view are new light functions that improve comfort and safety. We introduce five of these functions that are already available, and three that are still in the development stage.
Glare-free high-beam assistant: Many motorists make too little use of the high-beam function. The glare-free version offers the best possible range at all times. A camera-based system detects oncoming traffic, cars ahead and even cyclists, and controls the beam in a manner that prevents dazzling other road users, i.e. the high beam ‘masks out’ the oncoming car but still illuminates the areas right and left of the car at full power. Of course, drivers always have the possibility to switch to low beam. Glare-free high-beam lamps are available as xenon and LED models.
Adaptive headlights: Adaptive headlights are the ‘little brother’ of glare-free high beam assistants. They adapt their beam to the driving environment, i.e. inner-city traffic, country roads or motorways. Cornering lights also fall into the category of adaptive headlights. “Dynamic cornering lights are particularly convenient, as they follow the movement of the steering-wheel”, says Schreiber, pointing out the additional benefit of the system: less dazzling of oncoming traffic.
Light-emitting diodes: LEDs have long been the state of the art for rear lights, indicators, parking and daytime running lights. Now they are increasingly used for headlights too. While not necessarily outperforming traditional light sources – such as halogen and xenon – in terms of luminescence, the high colour temperature of LEDs ensures more brightness. High-end headlights reach the same light intensity as xenon, while simpler models supply approximately the same brightness as good halogen headlights but consume only around a quarter of the energy. A major advantage of LEDs is their long lifespan, which generally exceeds that of the car.
Matrix LEDs: This technology is also referred to as ‘pixelated light’. The headlights comprise a grid of multiple individually controllable light emitting diodes. These structures currently contain between 25 and almost 100 diodes; however, ambitious designers are aiming for up to a 1000 LEDs. Each of these LEDs illuminates a specific spot on the road. The headlights can thus produce glare-free high-beam and cornering lights without requiring mechanical parts. After high-end cars, this technology is now also available in cars such as the Opel Astra.
Laser light: This lighting technology is also powered by semiconductors. The beam of the laser diodes is directed onto a fluorescent phosphorous substance that transforms the monochromatic laser beams – which alone would only leave a hardly visible point on the road – into white light. Multiple safety systems contain the laser beams. At the present state of technology, the laser light is not particularly strong. The lights offer an extensive range of several hundred metres by closely concentrating the beams. The car itself must be equipped with additional normal headlights with a broader beam. The light-emitting surface of laser light headlights can be extremely small; sizes as small as a two-euro coin are possible, making these headlamps interesting for designers.
DMDs: Digital Micromirror Devices (DMDs) are known from cinematic equipment and projectors used for presentations. Thousands of tiny mirrors can direct or ‘mask out’ light at exactly pre-defined locations in fractions of a second. The result is similar to that produced by matrix LEDs but offers a higher resolution. Light designers are experimenting with this technology with the intention of introducing it to cars. However, this may still take some years.
OLED: Organic light-emitting diodes (OLEDs) for automotive applications are still in their infancy. However, they will not play a role as headlights in the future. When they have reached market maturity in a few years, they will be used to illuminate passenger compartments or in rear and parking lights. Here too, the focus is on the wide range of design options.
Caption: Good visibility: innovative headlight technologies for more safety and comfort.