Optical Analysis and Printing Process of Ultra-thin LED Backlight Guiding Plates

• Main Authors: Yi-Chen Tsai, 蔡一辰
• Other Authors: 武東星
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/60700994238085033703

碩士 === 國立中興大學 === 材料科學與工程學系所 === 98 === Abstract The current trend of TFT displays is towards energy efficiency and carbon reduction and the light-emitting diodes (LEDs) have been utilized as the emitter in the backlight module. In this period, the LED replaces the CCFL light source gradually and it performs better optical performance obviously as a result of creating the module thinner. Currently, the ultra-thin light guiding plates are manufactured by the ejection molding method. However, the ejection molding can only be applied for small-size light guiding plates. It is well known that the LED backlight modules are moving in large size. Therefore, the screen printing becomes a dominant technique in future large-size light guiding plates. This thesis focuses on the design of LED backlight module of the 24” light guiding plates. The parameters of the screen printing process for the light guiding plate are also investigated. The improvement and optimization of the optical pattern and printing process were confirmed to be the critical issues when the thickness of the light guiding plate is decreased. For the middle and larger light guiding plates, the major manufacture issue is lack of shelter, which will result in the dot size decreasing in the design stage. Nowadays, the solvent ink with polyester screen only have 30 percent yield rate in the conventional screen printing process. It was found that the combination of UV ink printing with steel silk screen have achieved the yield rate of over 95% in the printing process. As a result, this process can not only accelerate the commercialization of the large-size ultra-thin light guiding plate import, but also improve the performance of light guiding plates with efficient cost reduction margin.