High resolution lighting comes to automotive headlamps

October 07, 2016 // By Christoph Hammerschmidt
After the introduction of laser and smart multi-segment lighting, many believed that the technological potential for the further development of automotive front lighting is exhausted. They should think twice: The next step could well be high-resolution LED headlight - with much more than the maximum of 84 segments implemented today. And with more application flexibility.

In a joint R&D effort, a group of companies and research institutions have developed an LED light source with 1.024 pixels; each one of them can be selectively switched on or off. This gives automotive lighting designers the possibility to implement smart, dazzle-free lighting concepts that are significantly more precise and adaptive that today’s implementations. Plus, the novel light source makes it possible to implement adaptive cornering light as well as levelling without any mechanical elements. The high-resolution lighting can clip out any number of segments, dynamically protecting oncoming traffic and pedestrians from being dazzled. The headlight beam can be adapted to any conceivable curve characteristic, eliminating dark peripheral areas in the driver’s field of sight.

The R&D group includes Osram, Infineon, automotive lighting expert Hella, carmaker Daimler-Benz as well as two Fraunhofer institutes. Three and a half years after the project named µAFS (for "micro-structured adaptive front-lighting system") started, the group now introduced the result of their work. In terms of technology, the system developed integrates 1024 white LEDs on a single chip along with the driver circuitry and a high-level interface that enables driver assistance systems to selectively control every single LED, or pixel. The group also introduced a headlamp containing two such active lighting units, one with a single LED chip, the other one with two of them. Daimler showcased a vehicle that has (of course) two such headlamps, adding up the resolution to 6000 LED pixels per vehicle.

The Osram chip with 1024 single LEDs,
each one addressable selectively

Besides integrating so many high-brightness LEDs with each one capable of drawing 11 mA of current, the project also was challenging in terms of semiconductor technology, because GaN LEDs and the Silicon driver circuitry had to be integrated in a single unit, explained Osram CTO Stefan Kampmann. Here, Fraunhofer stepped in: The Fraunhofer Institute Reliability and Microintegration (IZM) contributed its competence in connecting technology for LED and ICs and the materials required.