Freeform lens for application-specific LED packaging

Abstract

Traditional LED packaging always adopts hemisphere lens, although which can ensure high light output efficiency, its light beam is of circular symmetry and non-uniformity. Therefore, LED by traditional packaging cannot be applied in lighting directly and bulky secondary lenses have to be used, which will make the traditional lighting companies difficult to switch to LED lighting and the lamps are heavy. In this study, an effective freeform lens design method for extended light source was presented. With this method, we designed a freeform lens for street lighting, and integrated with this freeform lens, a novel application-specific LED packaging (ASLP), whose manufacturing process can be easily integrated into current LED packaging processes, was suggested. The results of both Monte Carlo ray tracing optical numerical simulation and the experiment show that the light beam is quite in agreement with the design target and the light output efficiency of this novel LED packaging is as high as traditional one. Moreover, comparing with traditional LED module with secondary optics, this novel ASLP module has advantages of higher system light output efficiency (~9%), compact size (~1/8) and convenience for end customers.