A block division dot method applied to the light guide plate design for small size LCD backlight

• Main Authors: Wan-Lung Yang, 楊萬隆
• Other Authors: Hsian-Chuen Huang
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/56157038470023275558

碩士 === 清雲科技大學 === 電機工程研究所 === 94 === Using LED as the light source will save not only space but also electric power. Therefore, in recent years LED light source used the small size panels generally. The design of the backlight system of LED for small LCD panels adopts the form of a circular distribution because of the point light characteristic of LEDs. This will increase not only the difficulty level of the design but also the costs of manufacture. We therefore propose a new design concept of “block division dot” to improve the uniformity of the traditional design of dots. The new design has provided obvious improvements on the uniformity of brightness. Besides, the process of manufacture based on the new design is the same as that of the traditional light guide plate, and hence will not increase the manufacturing costs. In this thesis, we make use of the method of “block division dot” to design a 1.2-inch secondary LCD for cellular phones using a single LED as the light guide plate. Using the same method, we design also the light guide plate of the backlight system for use on a 2.2-inch and 3-inch LCDs respectively. After simulation, it is found that the degree of the evenness of light distribution of all the above LCDs has been greatly enhanced. Further, we propose also the technique of a 5mm extension of the light guide plate of the backlight module in order to achieve the effect of transferring the LED point-light source into the line-type source of the CCFL by way of a light expansion area through which it achieves twice the effect of light expansion. By simulation, the result indicates that it has a rather satisfactory performance of evenness of light on 3-inch and 6-inch light guide plates of backlight modules for LCD panels.