Establishing Functional Model of Photometric Performance of Trichromatic Light Sources in Chromaticity Diagrams

Abstract

In this study, we conducted a combined examination of the photometric and colorimetric performances of trichromatic light sources, which are synthesized by three kinds of light-source units, by transferring their photometric performance to chromaticity diagrams. Contour maps of three photometric performances, which are within a triangle gamut-area formed by three chromaticity coordinates relating to three-light-source-units of a trichromatic light source, were drawn to include the luminous efficacy of radiation (LER) in photopic, scotopic, and cirtopic vision. Functional models of the three different photometric performances as a function of chromaticity coordinates x and y based on the contour maps have been proposed. The functional models quantify all the photometric characteristics in the gamut area and can predict the performances for different synthesis of trichromatic light sources. Using the proposed model, it is possible to evaluate the present performance of trichromatic light sources and provide a method for optimization. An example of evaluation and optimization of a commercial RGB-LED light source was conducted using this proposed approach. Results show that the randomly chosen optimized points in the best optimization ways in the chromaticity diagram for LERs reach 16%, 31%, and 72% improvement in photopic, scotopic, and cirtopic vision, respectively.