Optical design of 3 independent freeform surface LEDs automotive dipped headlamp

In order to make sure of adequate lighting for the driver of the vehicle, and prevent the opposite driver from glare, an automotive dipped headlamp system with a cutoff line was designed. A dipped headlamp according to GB259912010 light distribution standard (automotive headlamps with LED light sources/or LED modules) was designed with highpower LED and free form reflectors (FFRs) which had simple structure and high optical efficiency. Based on the nonimaging optics theory, the correspondence between the angle of the light reflected by the freeform reflector and the coordinates of point in the target plane was established. The freeform lens point coordinates were calculated according to the correspondence of reflection and refraction laws. To achieve light distribution requirement, the fundamental surfaces were divided legitimately and the surface profile data of subsurfaces were optimized and adjusted. The function of dipped headlamp was realized by 3 LEDs, each of which had its own independent optical system. The test results show that the optical system has a clear cutoff line, with the efficiency reaching 54％, which can fully meet the requirements of the illumination of regulation on each test point.