以光學回授演算法搭配田口方法訂出電性調整液晶顯示 器模組閃爍之最佳方式

Optimization of the TFT-LCD Module Electrical Setting for Minimal Flicker by the Optical Feedback Algorithm and Taguchi Method

滿益秀(Yi-Hsiu Man)

指導教授 ： 陳念波

元智大學/電機通訊學院/光電工程學系/碩士(2012年)

摘要

現今多媒體影音市場熱絡，3C產品(Computer、Communications、Consumer-Electronics)幾乎人手一機，在3C產品的應用上，薄膜電晶體液晶顯示器(Thin Film Transistor Liquid Crystal Display，TFT-LCD)為目前3C產品中不可或缺的要角，薄膜電晶體液晶顯示器的品質控管，閃爍(Flicker)一直是各大面板廠十分注重的畫質品質項目之一，閃爍與共電極電壓(Common Voltage，Vcom)有密不可分的關係，同時也是許多研究與討論的課題。往往面板廠，針對尋找共電極電壓設定值使閃爍變輕微，通常在液晶顯示器模組(Liquid Crystal Display Module，LCM)電路設計時，電路中大多都會放一個可變電阻(Variable Resistor，VR)用來調整共電極電壓，這種作法好處是可用極低的成本，達到調整的目的，但是可變電阻的品質參差不齊，而且時常有可變電阻因運送或製程中遭受碰撞損壞，造成出畫不良，也無形中耗費許多生產的成本，另一種方法是在開發階段利用光學量測儀器搜集大量的樣品數據以訂定出理想的共電極電壓，搜集大量的光學數據是利用全因子的方式去作，這種方法很不經濟，耗費了大量的時間，也未必是精準的，而且在不同的批次產出的液晶面板，可能因面板製程差異、特性差異….等等因素，無法迅速找出理想共電極電壓的設定值，故基於改善這些缺點，此論文將以田口方法(Taguchi Methods)縮短實驗次數，搭配轉阻放大器(TransImpedance Amplifier )和光二極體(Photodiode)的應用電路，實現光感測器，配合邏輯演算法的自動修整(Auto trimming)程式，有效率且精準的找出理想共電極電壓設定值達到閃爍最小化的目的。
最後本論文規納出在液晶顯示器模組開發階段，以有效率的方式找出理想共電極電壓設定值使閃爍最小化的標準作業流程。

關鍵字

薄膜電晶體液晶顯示器 ； 閃爍

並列摘要

TFT-LCD (thin film transistor liquid crystal display) is ubiquitous on popular 3C products (computer, communications, and consumer-electronics). Regarding TFT-LCD manufacturing, flicker minimization is always one of the important items on the quality control list. Previous studies showed that flicker is closely related to Vcom (common voltage). An optimal Vcom setting suitable to the characteristic of the particular LCD can minimize flicker. One of the common practices in manufacturers, due to its low cost, is placing a VR (variable resistor) in the liquid crystal display module to adjust Vcom after assembled. The major drawback is that the adjustment often gets deviated and renders unqualified displays because of the VR’s quality and/or the shipping damage on VRs. Consequently, the yield gets degraded and the expense is wasted. Another way to set Vcom is finding its value during the circuit designing stage by sorting full-fledged optical measurement data from many LCD panel samples. This alternative method is not economical and cannot quickly handle the situation where the LCD panels from different lots have different characteristics than those previously sampled. In my study, the improvement on the latter method is made by applying Taguchi method to reduce the measurements and designing a quick and economical measurement apparatus. The new measurement apparatus is the application of trans-impedance amplifiers and photodiodes to make a photo sensor, and the custom-built algorithm “Auto trimming” to efficiently find the optimal value of Vcom for the minimal flicker. The novel method can greatly reduce the cost and the time needed to adjust Vcom for reduction of the flicker.

並列關鍵字

TFT-LCD ； Flicker

參考文獻

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