Tsinghua National Lab on Information Science and Technology, Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
A simple method is proposed to design freeform surface for Lambertian extended source. In this method, it can take advantage of the designing method for point source via substituting each incident ray with a dynamically calculated equivalent ray. For each facet on the freeform surface, the equivalent ray emits from the energy weighted average-emitting-position for the corresponding incident beam, and redirects into the direction which is determined by a source-to-target mapping. The results of the designing examples show that the light distributions’ uniformities can be improved by this method, e.g., even the improvement of 59% can be achieved.
nonimaging optics nonimaging optics illumination design illumination design light emitting diodes (LEDs) light emitting diodes (LEDs) Frontiers of Optoelectronics
2016, 9(2): 330