Light Output Feedback Control System Design for RGB LED Color Stabilization

• Main Authors: Shih Lung Lee, 李仕龍
• Other Authors: Hao-chung Kuo
• Format: Others
• Language: en_US
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/73922408309821893044

碩士 === 國立交通大學 === 顯示科技研究所 === 96 === LCD (Liquid Crystal Display) is the mainstream product to replace CRT (Cathode Ray Tube). Conventionally, CCFL (Cold Cathode Fluorescent Lamp) is used as a light source of LCD backlight. However, LED (Light Emitting Diode) is regarded as the candidate to replace CCFL (Cold Cathode Fluorescent Lamp) as light source of LCD backlight due to its wide color gamut, low operation voltage, mercuryfree characteristic, and fast switch response. The color shift due to heat effect after long time usage is an issue needed to resolve. In this thesis, a 14 bits recursive feedback control system is proposed and realized to stabilize the light output of RGB (red, green, and blue) LEDs by generating tiny recursive current in μA order. Whereas the just noticeable color difference (Δu’v’) of human is 0.005, feedback control system is proved that color difference (Δu’v’) of Red, Green, and Blue LEDs are kept within 0.005 under 13 bits resolution, and within 0.004 under 14 bits under aging simulation of 3250, 3969, and 4462 hours usage, respectively.