Use Pico-Laser to Engrave Glass Light Guide Plate with Microstructures

• Main Authors: Tsai, Hung-Cheng, 蔡閎丞
• Other Authors: Teng, Tun-Chien
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/gauvtr

碩士 === 國立臺灣師範大學 === 機電工程學系 === 106 === Recently, the large-sized, ultra-slim Liquid-Crystal Display(LCD) has become the mainstream. Therefore, the light guide plate (LGP) is becoming thinner, and the supporting components in the edge-lit backlight are removed to further reduce the entire thickness, which led the LGP made of PMMA too weak to support the backlight. In contrast, the LGP made of glass has much higher stiffness than that of PMMA and thus has become a potential solution. However, it is difficult to form microstructures directly on the glass LGP except screen-printing, but screen-printing has the limit for glass material. Because the Picosecond Laser (pico-laser) has the characteristics of nonlinear photon absorption and low heat affected zone suitable to machine the glass material, we tried to use the laser to fabricate a sample of the microstructure glass LGP and investigate the effects of the process parameters of the laser on the optical behaviors of the LGP. In this study, we tried to use a pico-laser of 532 nm to engrave a glass substrate (Iris glass, Corning) with concave microstructures to evaluate the feasibility of practically fabricating a LGP, and investigated the effects of laser processing parameters, including focus position, power, scanning speed, and scanning pitch on the morphology of engraving surface. In addition, we adopted two kinds of post-processing, thermal reflow and HF chemical wet etching, to smooth the microstructure of the sample and reduce stray light caused by surface roughness, thereby improving the light-emitting characteristics. Finally, we demonstrated a sample of the 6-inch glass LGP and verified the feasibility of fabricating a microstructure glass LGP using ablation by the pico-laser. With the optimal process parameters and distribution of pattern density, the average luminance and uniformity of the LGP sample is 1.03 x 103 cd/m2 and 0.793.