Review of optical design for vehicle forward lighting based on white LEDs

Abstract

We introduce a current development in optical design for vehicle forward lighting based on solid-state lighting, in particular, phosphor-converted white LEDs. The vehicles include bicycles, bikes, and automobiles. Although the requirements regulating different vehicles are different, the low beam always requires a high-contrast cutoff line. Three optical design ap- proaches are discussed; these include a projection lens incorporated with a baffle or beam shaper, multisegment reflectors, and complex lenses. A new design approach called light field manage- ment technology for the multisegment reflector is introduced. In addition, the possible related manufacturing errors and the robustness of different optical approaches are analyzed. Finally, we introduce three approaches to adaptive forward lighting that provide a driver with brighter and clearer vision without inducing glare to people on the roadway. The application of video pro- jection technology to roadway illumination could be a trend of vehicle forward lighting based on solid-state lighting. ©