田口方法結合灰色關聯分析應用於液晶顯示器背光模組導光板V溝微結構參數最佳化之研究

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

柏立文(Li-Wen Po)

指導教授 ： 于劍平

崑山科技大學/工程學院/機械工程研究所/碩士(2006年)

https://doi.org/10.6828/KSU.2006.00026

摘要

導光板(LGP)為液晶顯示器(LCD)中背光模組(BLM)的重要組件，因其控制液晶顯示器之光學輝度值大小與均齊度分佈。故要增加液晶顯示器光學顯示效率及輝度均勻性，必須針對導光板作設計。
　　本研究之重點為小尺寸液晶顯示器背光模組導光板V溝（V-Cut）微結構設計，包括導光板入光側V-Cut及底部V-Cut，並對其幾何參數進行光學輝度值大小與均齊度分佈之田口分析。導光板V-Cut微結構選取之幾何參數為入光側V-Cut個數、入光側V-Cut角度、入光側V-Cut間隔、入光側V-Cut深度、底部V-Cut角度、底部V-Cut間隔及底部V-Cut深度等七個參數；而分析之光學特性有輝度值（望大特性）與均齊度（望目特性）。
　　本研究採用田口方法以L9及L18直交表做參數配置，並建立導光板幾何模型與設定光學性質進行光學模擬分析。而導光板模型區分三個區域作輝度值及均齊度之數據量測，經分析結果計算S/N比後，總和各因素、各水準之S/N比計算值，得到回應表及回應圖，並求得影響導光板輝度值及均齊度的主要影響參數及最佳參數組合。接著藉由變異數分析（ANOVA）求得各因素之變動、變異及貢獻度，最後再以最佳參數組合作驗證分析。
L9入光側V-Cut田口分析結果顯示：導光板前、中、後三個區域最主要影響參數輝度值均為入光側V-Cut角度及入光側V-Cut個數；而影響均齊度均為入光側V-Cut角度及入光側V-Cut間隔。L18田口分析結果顯示：導光板的輝度值主要影響參數前區域為底部V-Cut角度；中區域為底部V-Cut間隔；後區域為底部V-Cut間隔。導光板均齊度最主要影響參數前區域為底部V-Cut角度、其次為底部V-Cut間隔；中區域為底部V-Cut間隔、其次為入光側V-Cut角度；後區域為入光側V-Cut間隔、其次為底部V-Cut間隔。最後，依據灰色田口分析可知：導光板多品質輝度值及均齊度之V溝幾何參數，影響最大為底部V-Cut間隔；其次為入光側V-Cut角度；再次為底部V-Cut角度。藉由本研究分析出的主要影響參數，可進一步得到導光板輝度值及均齊度的影響趨勢及其關聯性，同時亦可提供背光模組產業作設計及修正之參考。

關鍵字

V溝微結構 ； 灰關聯分析 ； 背光模組 ； 輝度 ； 均齊度 ； 導光板 ； 田口方法

並列摘要

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.

並列關鍵字

grey relation analysis ； Backlight module(BLM) ； Taguchi method ； V-Cut microstructure ； Light guide plate(LGP) ； uniformity ； luminance

參考文獻

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