Differential evolution for the optimisation of multi-band white LED light sources

This paper joins the quest for a white-light source based on mixtures of multiple narrow-band light-emitting diodes (LEDs) with the spectrum optimised for high radiant luminous efficacy and good colour-rendering properties. The complexity of the optimisation process increases with the number of LEDs used to create the white-light source. This paper describes an effective approach for mixing narrow-band LED spectra based on differential evolution, a simple and easy to use direct search method. Two MATLAB programs are designed allowing optimisation using the colour-rendering index and colour quality scale systems. Optimal theoretical solutions for four-LED and six-LED mixtures are analysed.