Practical Research And Design Of Side-Emitting Micro-Optical Light Pipe Used In Backlight Module

LCD products become more and more popular around the world because of its many advantages, such as low emission, low power consumption, compact package, exquisite image quality and so on. Since Liquid crystal can not shine, it’s necessary to have an additional light source to provide the illumination, so LCD backlight module is an important part of the whole product. CCFL was used in the traditional LCD backlight module, but CCFL has many disadvantages, such as contamination, large power consumption, poor image quality, short life span, so CCFL is being phased out. LED sources are more and more used in the backlight module in these years for its excellent performance of color and saving energy.In the early work, we proposed a LED side-emitting micro-optical lightpipe which can transform LED light from point source to linear source and has the advantages of both LED and CCFL when used in LCD backlight module. In this paper, we continue to explore its performance in deep study. In order to meet the need of LCDs’changing sizes, we optimize the dots arrangement formula, then the specific dots arrangement of the light pipes with different lengths is presented, so light pipes with different lengths can have good performance. the light uniformity of the pipe is up to 93% and the utilization efficiency can reach to 63%.Then, combine light pipe with RGB LED and calculate the luminous flux of each RGB LED by theoretical formula to mix standard white colour, then achieve timing display.Later in this paper, the light pipe is applied in edge-lighting backlight system and direct-lighting backlight system. From the simulation results, the uniformity of edge-lighting backlight system is up to 85% and the uniformity of direct-lighting backlight system is up to 90%. Verified through the simulation experiments, the light pipe can be used in LCD backlight module very well and has broad prospects for development.