Green phosphor converted light emitting diode

摘要

A light source having emissions in a plurality of spectral bands. The simplest light source according to the present invention is constructed from first and second light sources and a dichroic beam splitter. The first and second solid state light sources emit light in first and second bands of non or only partially-overlapping wavelengths. The dichroic beam splitter combines light from the first and second solid state light sources by passing light in the first band while reflecting light in the second band to generate light having a spectral content in the first and second bands. The solid state light sources are preferably arrays of LEDs, VCSELs, or edge emitting semiconductor lasers. A light source having improved radiance in the green region of the spectrum can be constructed by utilizing first and second solid state light sources that emit in different bands in the green portion of the spectrum. A white light source can be constructed by utilizing a third solid state light source and a second dichroic beam splitter and by choosing the emission bands of the light sources such that light leaving the second dichroic beam splitter is perceived as white by an observer when all three solid state light sources are emitting light. This light source has a radiance that is higher than the radiance of each individual solid state light source.