Liquid-crystal-modulated correlated color temperature tunable light-emitting diode with highly accurate regulation

Opt Express. 2015 Feb 9;23(3):A149-56. doi: 10.1364/OE.23.00A149.

Abstract

A precise correlated color temperature (CCT) tuning method for light-emitting diodes (LEDs) has been developed and is demonstrated in this article. By combining LEDs and a liquid crystal (LC) cell, a light source with continuous CCT variation along a straight track on the chromaticity diagram is achieved. Moreover, the manner of CCT variation can be modulated by choosing appropriate LEDs and phosphors to yield a variation going from 3800 K to 6100 K with the track near the black-body locus. By adapting various developed LC technologies for diverse demands, the performance and applications of LEDs can be greatly improved.