Free-form Optical System For High-power LED Automobile Headlamp

With the rapid development of automobile industry and continuous improvement of LEDtechnology, LED is becoming more and more common in automotive lighting. As LEDlight features are different from traditional light source, the second optical design for LEDneeds to be done. However, free-form surface is flexible to design, compact spatial layout,high energy efficiency, it is very suitable for LED lighting system design. This issue is aboutexploratory study on free-form surface applied in optical design for headlamp lighting system.Specific work as follows:Firstly, through analyzing development status and prospects of automobile industry andLED headlamps, the significance of this research is explained. The lighting requirements ofnational standard automobile headlamp are studied. After introducing the non-imaging opticstheory, the basic concepts of photometry, free-form surface optical design method anddesigning process for headlamp optical systems are also explained.Secondly, basing on studying and concluding the free-form optical design method, twodifferent optical design methods are proposed: free-form reflector and free-form lens.According to the spatial light intensity distribution of light source and the specific lightingrequirement for headlamp, by establishing energy and vector corresponding relationshipbetween the angle of the light exit from LED source and the coordinates of point in the targetplane according to energy conservation principle and Snell’s law, and with introducingilluminance optimal factor, the coordinates for the optical reflector was solved out based onnon-imaging optics theory, and the reflector entity was built up by mechanical modelingsoftware.Thirdly, after ray tracing the above-mentioned optical model in professional simulationsoftware, the generated light type and luminance distribution can fully meet the requirementsof GB25991-2010, which verifies the correctness of the described design method.Finally, a conclusion for all work is made and future research is put forward, whichneeds to further study.