Realization of high spatial color uniformity for white light-emitting diodes by remote hemispherical YAG: Ce phosphor film

High spatial color uniformity is realized by fabricating high power white light-emitting diodes (LEDs) with hemispherical YAG: Ce phosphor film. An injection molding process is developed to produce the phosphor film. By better control of the process, homogenous distribution of the phosphor particles is achieved. The color uniformity can be as high as 80%–90%. Comparing with white LEDs fabricated by traditional phosphor dispensing method and commercial samples with conformal phosphor coating, improvements of spatial color uniformity are around 36%–43% and 6%–8%, respectively, by the hemispherical phosphor.