Design of a 10-inch Backlight Unit with High Brightness

• Main Authors: Chang,CHIH-CHIANG, 張智強
• Other Authors: Chen,Chao-Hsien
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/46750092123750816560

碩士 === 國立高雄應用科技大學 === 機械工程系 === 105 === The thesis demonstrated the optimal V-cut design for brightness enhancement in a 10 inch backlight unit, BLU (Back Light Unit) using the Taguchi experimental method. The bottom angle of the V-cut on the emitting surface is 30 with a pitch ratio of the platform-to-V-cut, 1:1. Moreover, the two angles of the V-cut patterns on the reflective surface, namely the 1st reflective angle & 2nd refractive angle are 15 & 51.5, respectively. The brightness was found to perform as 13,734 ~ 13,779 cd/m2, 10% higher than the fundamental design, simple circular shape of optical laser dots. Nowadays slim, power saving and high efficiency requirement becomes significantly strong. Generally the ways to increase efficiency are to improve performance of LEDs, brightness enhancement films, BEF and LGP designs which are core technologies for a BLU company. Optical patterns, such as etching and printing dots have been widely applied in a BLU due to rapid procedure and lower manufacturing cost. However, it is difficult to increase brightness using these dots due to the characteristics of diffusion effect. On the contrary, brightness of a BLU can be significantly increased using collimated optical patterns, V-cut dots, which is the critical part in this thesis. Optical collimated patterns were conducted in this research to enhance brightness in a BLU. To achieve high brightness and to optimize pattern design, the Taguchi experimental method was used to simplify Full-Factorial Experiments and the results were further compared in simulation using LightTools. First of all, the uniformity was optimized based on minimum / maximum brightness to be 90  5%. Secondly, the maximum brightness varying with the angles of the V-cut patterns and pattern distribution achieving the uniformity of 90  5% was simulated using LightTools. According to the experimental results, the brightness was enhanced by 1.34% ~ 1.5% using V-cut patterns on the emitting surface higher and circular patterns on the reflective surface than that on smooth emitting surface. Moreover, the brightness was improved by 8.51% higher using the optimal V-cut patterns on reflective surface. To further analyze brightness varying angles of V-cut patterns on reflective surface and lenticular patterns on emitting surface, the brightness enhancement from lenticular patterns on the emitting surface was found to be 1.6% and dominated total brightness gain by 67%. On the other hand, brightness gain varying with the angles of the V-cut pattern on the reflective surface was found to be 1.3% and only dominated the total brightness gain by 33%.