The Study of Light Leakage in a Flat-Type CCFL Blacklight Unit

• Main Authors: lon, 羅益榮
• Other Authors: 林振峰
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/92137256089068666166

碩士 === 南台科技大學 === 電機工程系 === 95 === While the back light module companies carried out the product development and met the problem of optical grade, most of them performed the improvement of grade by trial and error method or experiential rule, for example the method of change in size and reducing the gap, to decrease the abnormal situation of grade, but few carried out the analysis for the abnormal grade, and often caused the situation of strategy failed or uncompleted. There are many kinds of the optical grade of back light module, the most occurred problem of grade is the light leakage on the light entry side of the radiating surface. This paper takes light leakage as the subject to investigate the causes and the improving way of the abnormal grade by optical principle. This paper takes the 17” flat plate back light module as basic framework, and uses the optical simulating software SPEOS as the tool to carry out the simulation, and sets up three parameters, the R angle of light guide plate, the gap between light guide plate and reflector, and the gap between light guide plate and light cover, to carry out the study of the light leakage analysis, and uses the quantitative data to analyze the testing result and find out the optimal parameter condition, and integrates the optimal conditions obtained, in order to analyze the overall level of improvement the light leakage. For the actual situation, the ideal parameters that set in this study can not often be realized, such as it is impossible of the R angle of light guide plate to be fully right angle, no gap between light guide plate and reflector, and no gap between light guide plate and light cover; for such kind of problem, this study takes above experimental result as the base of reference to change the structure of the light entry side of back light module, and gets the result by the way of optical simulation and compares with the optimal result by optics, to discuss the improvement of practicable enhancing mechanism on light leakage. Finally, combining the above experimental result we could find that, the reduced R angle of light guide plate and the reduced gap between the mesh point of light guide plate and reflector could significantly reduced the situation of light leakage. In addition, reducing the amount of light leakage could increase the central luminance. These studied parameters could be the reference on the design of the back light module in the future, and the technology of production could also be improved toward the ideal parameters, and reach the enhancing treatment of the light leakage situation.