Color Rendition Engineering of Phosphor-Converted Light-Emitting Diodes

We present an approach to the optimization of the trichromatic spectral power distributions (SPDs) of phosphor-converted (p-c) light-emitting diodes (LEDs) in respect of each of four different color rendition properties (high color fidelity, color saturating, color dulling, and color preference). The approach is based on selecting a model family of Eu2+ phosphors and finding the optimal peak wavelengths of the phosphor bands as functions of the luminous efficacy of radiation. A blue component due to either phosphor photoluminescence or InGaN electroluminescence with the peak wavelength at about 460 nm was found to be an optimal one for the high-fidelity, color-dulling, and color-preference LEDs. The high-fidelity and color-preference LEDs need red phosphors with the peak wavelength of 610-615 nm. The high-fidelity LEDs were shown to require a true green (~530 nm) phosphor component, whereas a cyan (~510 nm) component is the prerequisite of the color-saturating and color-preference LEDs. Deep-blue (~445 nm) and deep-red (~625 nm) components are required for the color-saturating LEDs. A broad yellow band similar to that of Ce(3+) emission is to be used in the color-dulling LEDs. The SPDs of practical phosphor blends for the high-fidelity, color-saturating, and color-preference p-c LEDs are demonstrated.