Spectral design methods for multi-channel LED light sources based on differential evolution.

The methods were proposed to design the spectra of light sources with multi-channel LEDs based on a differential evolution (DE) algorithm. Specifically, to produce a desired illuminance level while matching a specific spectrum, a matching method combining the DE algorithm and photometry was verified by matching the Commission Internationale de l'Eclairage (CIE) standard illuminants A and D65 at the two desired illuminance levels (500 and 1000 lx) with a multi-channel LED array. Furthermore, considering that correlated color temperature (CCT), illuminance, and color rendering are of practical importance to general lighting, on the basis of photometry and colorimetry, the DE algorithm integrating a mechanism dealing with constraints was developed to optimize the CIE general color rendering index of light sources under a joint target of CCT and illuminance. Sixteen selected targets (eight CCTs from 2800 to 6500 K at 500 and 1000 lx, respectively) were realized with the LED array. The results indicate that the relative errors of CCT and illuminance are less than 0.7% and 1.5%, respectively, while achieving excellent or even perfect color rendering. These methods also enable a practical tool for smart and dynamic lighting.