Analysis for optical extend in light-pipe illumination system

Based on optical extend, non-imaging optics was used to optimize the light-pipe lighting system. The transfer of optical extend in light-pipe was analyzed. The detailed analysis and experiment show that a balance between the section size of the light-pipe and the F number of the light beam should be reached to acquire best performance. Theoretically the optimal ratio of the height of the light-pipe to the radius of the light beam is 1.535, it will change slightly in the different systems. So a new method to limit the facula was presented to improve illumination efficiency of light-pipe.