Abstract

There is a strong worldwide drive to efficient general lighting using white light emitting diodes (LEDs) [1,2]. White LEDs often consist of a semiconductor diode [3,4,5] combined with luminescent phosphors [5] to convert part of the blue light to green yellow, and red. In state-of-the art white-light LEDs one exploits multiple scattering of light [1,2]. The transport of light then becomes diffusive, which serves to obtain a desirable smooth lighting without hot spots and without angular color distribution. Moreover, photons are recycled so that thin phosphor layers serve to improve cost efficiency and reduce environmental impact.

© 2013 IEEE