Design of LED Light-Source Structure for Direct Backlight

• Main Authors: Kai-Hung Cheng, 鄭凱鴻
• Other Authors: Jin-Jia Chen
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/64276906957195429341

碩士 === 國立彰化師範大學 === 電機工程學系 === 97 === The purpose of this thesis is mainly to design a novel light-source structure to change the Lambertian-like radiation distribution of the light emitting diode (LED) into a uniform distribution and then to apply it to a large scale direct backlight module. This LED light-source structure includes a bare LED and a rectangular 3D structure, which has a small semi-spherical cave at the center of the bottom, so that a uniform distribution of light rays emitted from the LED light source can be obtained via refraction, reflection, and total internal reflection. The use of the light-source structure to a backlight module can achieve the requirement of the brightness uniformity even without a diffuser sheet, and thus the product cost can be reduced. For better performance of the proposed light-source structure, a genetic algorithm is also employed to find the optimum parameters of the structure so that the optimal brightness uniformity of the backlight module can be achieved. The simulation results show that the brightness uniformity of 94.75% and the whole optical efficiency of 72.29% can be obtained for a 46-inch backlight module.