In the context of the research project VoLiFa 2020 (fully adaptive light distribution for intelligent, efficient and safe vehicle lighting) funded by the Federal Ministry of Education and Research (BMBF), lighting and electronics expert HELLA and its project partners have developed and constructed a headlamp on the basis of a Liquid Crystal Display (LCD).
The system requirements of automobile manufacturer Porsche and the Research Institute for Lighting Technology and Mechatronics of the University of Paderborn (L-LAB) served as foundation. Further project partners were Merck, the Institut for Grossflaechige Mikroelektronik (IGM) of the University of Stuttgart, Elmos Semiconductor and Schweizer Electronic.
A further step toward the digitalization of light
The new LCD headlamp projects a total of 30,000 pixels onto the road. This allows adjusting the light pattern in an intelligent and continuous manner to various driving situations in real time. This process is increasingly digital, i.e. software-controlled. Individual segments with e.g. other traffic participants or strongly reflecting street signs can be omitted or dimmed in a targeted manner. Highly complex functions are conceivable: navigation arrows can be projected onto the road, e.g. for identifying the ideal driving lane. Christian Schmidt, head of pre-series light development at HELLA: «LCD technology enables functions that will also be relevant to autonomous driving. We will therefore make the technology fit for serial production.»
LCD headlamps work with camera and Lidar sensors
25 high-performance LEDs arranged in three rows serve as light source.The LED’s individual light intensity will be adjusted to the respective lighting situation. The LC display, however, is the innovative core component of the innovative headlamp. It is situated between the LED light source and the projection lens. The display generates a matrix with 100 x 300 pixels that can be individually controlled and dimmed. A camera installed in the vehicle as well as a sensor optically reading distances and speeds (light detection and ranging sensor Lidar), will forward the ambient information to the headlamp control unit via a processor. This will then direct the individual display pixels up to 60 times per second.
HELLA developed the concept for the LCD headlamp’s optical system during the research project. Ensuring high system efficiency and a thermal concept guaranteeing the automotive suitability of the module were among the various other HELLA tasks. A special liquid crystal was necessary, which Merck developed for this purpose. Finally, HELLA provided the integration of the various components into the overall system and developed an interface between lighting control and headlamp. The University of Paderborn is currently testing the prototype of this innovative headlamp under realistic driving conditions.