Optimization of designing LGP V-Cut microstructure parameters for BLM in LCD by Taguchi method with grey relation analysis

• Main Authors: PoLi-Wen, 柏立文
• Other Authors: Jiahn-Piring Yur
• Format: Others
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/20412280671844557591

碩士 === 崑山科技大學 === 機械工程研究所 === 94 === The Light guide plate(LGP) is an important component of Backlight Module(BLM) which is part of Liquid crystal display(LCD), dominating the value of luminance as well as the uniformity of LCD. It should be considerably designed for LGP to further improve the optical display efficiency and uniformity of LCD performance. This research aimed to evaluate the influencing parameters of geometrical shape of V-Cut microstructure on a small size LGP. The V-Cut microstructures included incidence lighting and bottom side of LGP. Taguchi method was employed for correlating geometrical parameters, optical luminance value and uniformity of LCD. Seven V-Cut geometrical parameters were selected, including the amount of incidence side V-Cut, angle of incidence side V-Cut, interspacing of incidence side V-Cut, depth of incidence side V-Cut, angle of bottom side V-Cut, interspacing of bottom side V-Cut, and depth of bottom side V-Cut. The luminance value (large-the-best) and uniformity (nominal-the-best) of optical characteristics were analyzed. Taguchi Method L9 and L18 orthogonal array were employed to layout experiment arrangement in this study, and then constructing LGP geometrical model and the optical properties for optical simulated analysis. The LGP was divided into three regions for measuring the luminance value and uniformity. After calculating and summing up the S/N ratios under various factors and levels, response tables and diagrams were generated as well as the main influencing and the best-collocated parameters of luminance value and uniformity of LGP. Using ANOVA analysis the variation, deviation, and degree of contribution of parameters were found. Finally the optimal combination of parameters must be confirmed by confirmation experiment. The L9 Taguchi analysis results of incidence side V-Cut showed that the main influencing parameters of affecting the luminance of LGP front, middle and rear regions are the angle and amount of incidence side V-Cut. It also showed that the main influencing parameters of the uniformity of LGP front, middle and rear regions are the angle and interspacing of incidence side V-Cut. However, the L18 Taguchi analysis results showed that the main influencing parameter of affecting the luminance were the angle of bottom side V-Cut for front region, and the interspacing of bottom side V-Cut for middle and rear regions. They also showed that the main influencing parameters of affecting the uniformity were the angle and interspacing bottom side V-Cut for front region, the interspacing of bottom side V-Cut and angle of incidence side V-Cut for middle region, and the interspacing of bottom and incidence side V-Cut for rear regions. Finally, based on the results of Grey-Taguchi analysis for multi-quality optimization, the main influencing parameter of affecting the luminance and uniformity were the interspacing of bottom side V-Cut. Using the main influencing parameters obtained in this investigation, the LGP effecting tendencies and relationship between those parameters and the LGP performance could be found. This may provide valuable consultation of the BLM design and modification for industries.