Color Temperature Tunable LED White-Light With High Color Rendering Research

Color rendering and light efficiency are two important factors to evaluate the quality of LED light source. While it is always the problem we have faced that the LED light source with poor color rendering. This paper states a mathematical model for simulating LED relative spectra, the functional relationships of LED relative spectra and the output luminous flux, input power, drive current are established. The simulation program of color rendering of white light LED clusters was developed according to the principle of additive color mixture and CIE method of measuring and specifying color rendering properties of light sources. The program can predict the spectral power distribution, chromaticity coordinates, color rendering indices, LED drive currents, luminous flux, input power, luminous efficacy of white light LED clusters. For given color temperature, high color rendering white light LED clusters with white phosphor-coated LED and red LED (W/R LED Cluster) were found by simulation analysis on spectra mixture of blue chip, yellow phosphor, green phosphor, and red LED. By further simulation we get the white light LED cluster with white phosphor-coated LED and red LED where the white phosphor-coated LED has different color temperature adopt special fluorescent ratio. For color temperature tunable white light, WW/R/G/B LED cluster, CW/R/A/G/B LED cluster, NW/R/G/B LED cluster and NW/R/B LED cluster white-light with CRI and R9 all above 90 at color temperature tunable from 2700K to 6500K were found by simulation analysis. Color temperature tunable WW/R/G/B LED cluster, NW/R/G/B LED cluster and NW/R/B LED cluster with high color rendering white light were success realized in our lab, the result shows that W/R LED cluster can realize fixed color temperature white-light with high color rendering, and NW/R/B cluster can realize color temperature white-light with high color rendering and high luminous efficiency.