A Study About Color Uniformity In The Second Optical Design For LED White Light

Currently, the most primary way to produce a white Light Emitting Diode (LED) is to mix a blue light stimulated by LED chip and a yellow green light stimulated by the blue light. When processed by optical elements, the light source will cause phenomenons such as a yellow circle and blue heart, yellow and white stripes in light spot. It’s of great difference with traditional light source. Therefore, great attention should be paid to color uniformity in LED light fixtures design.Under most time, vary optical structures of light fixtures can be designed by optical software, and some defects can be avoided by optical software. However, it remains a difficult task to simulate color uniformity of LED light fixtures in optical software. The key of this task lies in the establishment of LED light source model. With the same optical device, different light sources will cause different light and shade effects. As a matter of fact, white LED should be regarded as a blue emitting body and a yellow one, rather than being considered as a whole. In practice, a great deal of experimental data is needed.This paper will establish a binary model theoretically based on great references and previous studies. And the model will be established in the software of Lighttools, while experimental data will be collected to compare with simulative data to prove this model. Furthermore, through the designs of optical structures in light fixtures, the practicability of this model will be testified.By analyzing the chromaticity distribution of white LED light source and various phenomenons produced in its secondary light design, this paper will contribute to choose reasonable lighting structures, so as to avoid unsatisfactory light distribution.