Study on Color Rendering of Light Communication Source Based on Multi-Chromatic LED

Visible Light Communication (VLC) is an emerging technology which combines LED lighting engineering and optical communication technique. In this article, we aim at the problems of bad color rendering, low luminous efficacy and non-adjustable color temperature of white LED lighting communication source. We did some researches according to the multi-chromatic white LED communication theory. Meanwhile, we used the Gaussian distribution put forward by Yoshi as the spectral model of chromatic LED, and made use of the general color rendering index (R_a) which is recommended by CIE and the general color quality scale (Q_a) recommended by National Institute of Standards and Technology (NIST) to evaluate the color rendering of light source. We adopted Genetic Algorithm to optimize single color temperature and adjustable color temperature scope 2 700 to 6 500 K based on principle that R_a and Q_a are greater than 80 to optimize the best combination of spectra of adjustable color temperature light source. At last, according to the result of the experiment, we analyzed the relationship among the color rendering, luminous efficacy of radiation (LER) and adjustable color temperature of the light source. It turned out that tri-chromatic adjustable color temperature white LED's peak wavelength combination which satisfies the best color rendering is 613 nm/541 nm/464 nm. Meanwhile, when the minimum of R_a and Q_a are 81.2 and 81 respectively, it can meet the demand of lighting communication in the general situation. And the tetra-chromatic adjustable color temperature white LED's peak wavelength combination which meets the best color rendering is 620 nm/562 nm/505 nm/449 nm. The minium of R_a and Q_a are 96.7 and 92.2 at the same time. When in a spot which requires special lighting or higher communication rate, we should use tetra-chromatic LED white light as the lighting communication source. In the article, we have simulated the best spectral combination of LED. And it can provide some references for the design of visible communication light source used in the wide channels.