液晶顯示器已成為平面顯示器市場的主流，而液晶盒間隙決定液晶顯示器的顯像品質及光電特性。本研究提出ㄧ種以掃描白光干涉術量測液晶盒間隙的新方法。不需複雜的理論模式及耗時的資料比對。此新方法的基礎為低同調串聯干涉術，量測系統包含白光光源、掃描麥克森干涉儀及待測液晶盒。掃描干涉儀與液晶盒以串聯式排列在一起，所以可避免液晶盒上層玻璃色散的誤差。白光通過麥克森干涉儀後，一半被導向參考光偵測器中，另ㄧ半則入射至液晶盒，而液晶盒的反射光由量測光偵測器接收。
在掃描干涉儀的光程差連續變化過程中，當兩干涉臂等長時，參考偵測器會偵測到白光條紋，此位置為參考零點。而當干涉儀光程差等於液晶盒內任兩介面的兩倍光程時，量測光偵測器亦會出現白光條紋，由於液晶盒的層狀結構，會有多組白光條紋出現。 將量測訊號與參考訊號相減，藉以降低中間干涉波包影響，再經過波包質心標定後，由這些波包質心相對位置，即能直接求得液晶膜層厚度。以此掃描白光干涉儀量測空液晶盒、扭轉型液晶盒及多區域垂直配向液晶盒，其間隙標稱值分別為5 μm、3.5 μm及4.2 μm，結果顯示空液晶盒的量測偏差小於0.1 μm，而另兩個液晶盒的量測偏差約為0.4~0.5 μm。

The cell gap of a liquid crystal display (LCD) determines the LCD’s image quality and photoelectric characteristic. This research proposes a scanning white light interferometer (SWLI), based on low coherence tandem interferometry, for measuring the liquid crystal (LC) cell gap. The theoretical model is simple, and no time-consuming library matching is required. The SWLI consists of a white light source, a scanning Michelson interferometer (SMI), and a LC cell. The SMI and LC cell are in tandem and thus can prevent the dispersion error caused by the upper glass of the LC cell. The light is first directed to the SMI. Then a beam splitter divides the output beams of the SMI into two parts. One part is collected by a reference detector. The other part is incident on the LC cell, and the reflection from the cell is received by the measuring detector. The optical path difference of the SMI is continuously changed and the output signals of the detectors are recorded. The normalized reference signal is subtracted from the normalized measuring signal to reduce the influence of the central white light fringe, which is always generated when the path difference in the SMI is zero. After zero-order interference fringes are identified with centroid algorithm, the cell gap is directly determined from the separation between these fringes. Three different cells were measured with the SWLI. The nominal gaps of empty cell, twisted nematic (TN) cell, and multi-domain vertical alignment (MVA) cell are 5 μm, 3.5 μm, and 4.2 μm, respectively. Experimental results show that the deviation is about 0.1 μm for the empty cell, and the deviation for the other two cells is 0.4~0.5 μm。

誌謝 i
摘要 ii
Abstract iii
目錄 iv
圖目錄 v
表目錄 vii
第一章�緒論 1
1.1 研究動機 1
1.2 研究背景與發展現況 2
1.3 研究方法 5
1.4 論文架構 6
第二章�液晶盒結構與光學特性 7
2.1 液晶簡介 7
2.2 液晶的種類 7
2.3 液晶之光學原理、介電異向性及變形理論 10
2.4 常見的液晶盒種類 14
第三章�液晶盒間隙量測理論 18
3.1 低同調干涉術 18

3.2 串聯式干涉儀 22
3.3 液晶盒間隙量測原理 25
第四章�掃描白光干涉儀 28
4.1 系統架構 28
4.2 光路調整與量測方法 30
4.3 液晶盒間隙自動化量測 31
4.4 液晶盒間隙計算方式 33
第五章�實驗結果 40
5.1壓電微動台測試 40
5.2 液晶盒玻璃在低同調麥克森干涉術的量測限制 42
5.3 液晶盒間隙量測 45
5.4 誤差分析 46
第六章�結論與展望 48
參考文獻 50

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