多功能且具成本效益之液晶顯示單元光學參數量測系統的發展

Abstract

近年來，政府極力推動「兩兆雙星」計畫，使得光電平面顯示器儼然成為我國重點發展產業科技項目之一；例如，2005年台灣顯示器產業在全球該類產品的市場佔有率已達31%。該項科技產值在台灣光電產業中，佔有63%之比例(約新台幣7,141億)，位居第一名，且預計逐年擴增，其中液晶顯示器佔有絕大多數的比例(約新台幣7,013億)。因此，為了有效提升液晶平面顯示器產量與品質管制之需求，進行液晶顯示單元之光學參數量測系統技術之研究與發展是刻不容緩的。 我們的目標係發展一套多功能且具成本效益之液晶顯示單元光學參數量測系統，來降低該類儀器的成本，以期能減少對國外廠家的依賴，進而提高國內顯示器產業的競爭力。在本論文中，我們首先進行過去作法之系統架構的學理分析與性能評估，然後提出一個簡單的系統結構且相當經濟的方法，來達成多功能的量測系統。此系統是以起偏器-液晶單元-補償器-檢偏器架構為基礎，透過晶體旋轉法量測液晶單元之預傾角(pretilt angle)，再使用極化量測法來量測其間隙(cell gap)與扭動角(twist angle)等，攸關液晶顯示品質的重要光學參數。除此之外，此系統還可測量電壓-穿透率曲線(voltage-transmittance (V-T) curve)等光電特性。針對此系統，我們提出學理、模擬、實驗與系統製作的方法，並且說明整體的可行性分析。實驗的結果顯示此方法所量測的結果是相當令人滿意的(例如，液晶單元間隙的誤差百分比為1.45%)。For years, the government has promoted the “Two Trillion and Twin Star Industries Development” plan. As a result, the flat panel displays (FPDs) had become one of the most important industrial applications. For example, the FPDs in Taiwan occupied 63% (about $NT 7,141 hundred million dollars) of the optoelectronics industry in Taiwan and 31% in the market of the FPDs in the world in 2005. Therefore, to promote effectively the output and quality of the FPDs, it is very urgent to research and develop the LC cell optical parameter measurement systems. The objective of this paper is to develop a multiple-function and cost-effective measurement system to lower the dependency of foreign instrument makers and to reduce the manufacturing cost for the industry. In the paper, we first study the past approaches and analyze their measurement performance. Then, a simple and cost-effective method will be proposed to achieve the multiple functions. This system on the basis of the PSCA configuration uses the crystal rotation method to measure the pretilt angle of the sample under test, and the polarimetry to measure the cell gap and twist angle of it. These optical parameters highly influence the display quality. That is, in addition to the measurement of the three important optical parameters, this system can also measure the voltage-transmittance (V-T) curve. For this system, we will do the theoretical study, simulation, experiment, system implementation to show its feasibility. From the experiment results, it is shown that the measured results were quite satisfactory. For example, the error percentage was 1.45 %.