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LCD-controlled headlights turn cars into powerful projectors

Technology News |
By Julien Happich


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).


Among Hella’s responsibilities was guaranteeing a high system efficiency as well as developing the thermal concept which ensured the module’s automotive compatibility. Necessary was a particular liquid crystal, developed by Merck for this purpose. Elmos Semiconductor designed and produced innovative electronic semiconductor components, which were embedded into the circuit board by Schweizer Electronic. HELLA integrated the components into the overall system and developed an interface between light control and headlights. A prototype was built, which – integrated into a Porsche Panamera – is currently being tested in realistic driving situations by the University of Paderborn.

Due to the growing volume of traffic and the increasing security requirements, intelligent lighting systems are gaining in importance. The LCD technology allows new functionalities and possibilities. The application is not restricted to passenger cars. Also in other vehicle classes, such as commercial vehicles and buses, meaningful application fields result.

Related articles:

High resolution lighting comes to automotive headlamps

Concept car adopts multi-LED modules: headlamps double up as projectors

 


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