volume | PIER Journals

Abstract

RGB LED luminaires often exhibit nonlinear luminous-flux variation and chromaticity-coordinate drift during high-to-low brightness switching, reducing color stability at low brightness levels. To address this problem, this paper proposes a color-stability-oriented RGB LED color-mixing optimization algorithm. Nonlinear fitting is first used to compensate for temperature-induced luminous-flux variation and chromaticity shift. Then, a spectral reconstruction method based on Bounded-Variable Least Squares (BVLS)-constrained parameter mapping is developed to predict RGB-channel spectra and correct single-channel chromaticity coordinates under different duty cycles. Furthermore, a two-dimensional affine chromaticity-point mapping method is introduced to adaptively correct the target chromaticity point according to the variation of RGB primary chromaticity coordinates at different brightness levels. The proposed method is evaluated using chromaticity tolerance, CAM16, and CAM16-UCS. Experimental results show that the chromaticity tolerance can be maintained within four SDCM steps in the 1%-10% low-brightness range, while color appearance differences are reduced under different brightness conditions. These results demonstrate that the proposed method improves the color stability and visual consistency of RGB LED luminaires.

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Dr. Shumin Feng

Dr. Hao Chen

Dr. Shu Pan

Dr. Zongyuan Liu

Dr. Youqin Lin

Dr. Weiming Lin