LCD-controlled headlight enables adaptive light distribution

June 28, 2017 // By Christoph Hammerschmidt
What is the result if you combine LED floodlight with an LC display? Automotive lighting company Hella (Lippstadt, Germany) did it. The result is a headlight that can vary the light distribution in front of the car in a very flexible way: The headlight can adapt the light to the respective traffic situation and project guiding symbols to the road.

Brightness and light distribution of the LCD headlight are controlled by a 30.000-pixel display screen. This allows the light image to be adapted gradually and in real-time to the driving situation. Hella regards this technology as an enabler for future software-controlled lighting.

The driver gets the best possible view of the road. Individual segments in which, for example, other road users or highly reflective traffic signs are located, can be selectively hidden or dimmed. Complex lighting functions are also conceivable: Navigation arrows or lines which specify the ideal lane can be projected onto the road. "The LCD technology allows functions that will also be relevant for autonomous driving," says Christian Schmidt, head of lighting technology advanced development at Hella. "We will therefore bring the technology to production readiness."

The core component of the headlight is the LC display. It is located between the LED light source and the projection lens. The display generates a matrix of 100 x 300 pixels, which can be switched and dimmed individually. A camera installed in the vehicle as well as a lidar sensor that measures optical distances and velocities forwards the environmental information to the headlight control unit via a computer which adjusts the individual image points of the display up to 60 times per second. 25 high-power LEDs arranged in three rows are used as the light source. The brightness of each LED is adapted to the respective lighting situation.


The LCD-controlled headlight enables designers
to shape the lighted area in any desired way

The headlamp is the result of a joint R&D project with the universities of Stuttgart and Paderborn, carmaker Porsche, semiconductor manufacturer Elmos and electronic assembly expert Schweizer Electronic were collaborating with Hella who developed the concept for the optical system of the LCD spotlight. The whole project was based on the system requirements from Porsche and the Research Institute for Light Technology and Mechatronics of the University of Paderborn (L-LAB).