US Patent 7321191 Phosphor blends for green traffic signals

There is provided a blue-green illumination system, including a semiconductor light emitter, and a luminescent material, wherein the system has an emission with CIE color coordinates located within an area of a of a pentagon on a CIE chromaticity diagram, whose corners have the following CIE color coordinates: i) x=0.0137 and y=0.4831; ii) x=0.2240 and y=0.3890; iii) x=0.2800 and y=0.4500; iv) x=0.2879 and y=0.5196; and v) x=0.0108 and y=0.7220. The luminescent material includes two or more phosphors. The illumination system may be used as the green light of a traffic light or an automotive display.