Color-dulling solid-state sources of light

Abstract

The spectral power distributions (SPDs) of solid-state sources were optimized for rendering the highest number of colors with a perceptually noticeable reduction in chroma (dulling) while maintaining the hue distortion below an acceptable threshold. Statistical color rendition indices derived from the analysis of color-shift vectors of 1269 Munsell samples were used in the objective functions for the optimization of SPDs of the color-dulling sources. The starting optimization point was the SPD composed of narrow yellow and blue (YB) emissions, which both dulls colors and distorts hues. Two methods were applied to reduce the hue-distorting effect of the narrow-band YB source. The first method, broadening the spectral bands, yields SPDs similar to that of a dichromatic white light-emitting diode (LED) with the partial conversion of narrow-band blue electroluminescence to wide-band yellow photoluminescence. The second method, multiplying the spectral bands, results in the SPDs similar to those of trichromatic clusters of red, yellow, and blue (RYB) and amber, green, and blue (AGB) LEDs.