Optical design for uniform color mixing illumination system

Abstract

In many applications, the emitting light from LEDs with different colors need to be mixed together on a large scale target plane and this illumination mode is usually generated with the help of a diffuser. Abandoning the traditional method, we proposed a LED color mixing method which can produce an illumination pattern with both high color uniformity and irradiance uniformity. This method is composed of the two main aspects: arrangement of irradiance array and design of LED lens. With the method, an independent rectangular irradiance distribution is generated by each lens unit, and the large scale color uniform illumination is obtained by arraying the irradiance distribution. A 3×3 array of LED module units consisting of 36 LED lens units with 4 different colors are designed, and a desired result with high color uniformity is obtained. This color mixing method is feasible and practical, and is superior to the existing methods.