本研究基於利用穆勒矩陣偏光儀來量測液晶盒的各項光學參數。當不同線性偏振光穿透液晶盒之後，由於液晶具有光學異向性和旋光性，而造成原本的線性偏振態會發生改變。結合光學架構與史托克偏光儀來量測，當不同線性偏振光經過液晶盒之後的史托克參數來求得液晶盒樣本具有的光學非等性的特性。本研究的方法在於先量測液晶盒各種非等向性的光學等效特性，再由這些等效特性來計算出液晶盒內的扭轉角、預傾角與厚度。此方法不同以往的量測技術需要以演算法如基因演算法來演算出液晶盒的光學參數，此方法論是以等效參數概念出發進而計算出方程式的解，因此可以達到快速量測的需求。在實際量測上，對於一扭轉向列型液晶的測試片，其結果為扭轉角ϕ=89.864°、平均預傾角ξ=1.806°和厚度d=10.696μm，其與樣本的誤差值為∆ϕ=0.136° and ∆d=0.196μm，而平均預傾角ξ=1.806°亦在其樣本的合理範圍內。此外，本研究亦模擬求解不同類型液晶的光學參數如垂直排列型液晶，其模擬結果顯示對於此類型的液晶本方法也能正確求出其扭轉角、平均預傾角和厚度。

A simple analytical method to measure the cell gap, twisted and pretilt angles of a twisted nematic liquid crystal (TNLC) cell with effective optical parameters by Stokes polarimetry is proposed. In this approach, we first measure the effective optical parameters of a TNLC cell and then use the effective parameters to extract the physical optical parameters of a TNLC cell. Unlike the conventional methods using multiple wavelengths, this technique proposed is involved a single wavelength and supplies a simpler and cheaper methodology to analytically extract three physical parameters. As a result, the experimental results show that the extracted values of the twist angle, pretilt angle and cell gap are ϕ=89.864°, ξ=1.806°, and d=10.696μm, respectively. The error between the known values and experimental data are ∆ϕ=0.136° and ∆d=0.196μm, respectively. The other simulations results show that extracted values of the twist angle, pretilt angle, and cell gap of a vertically aligned liquid crystal (VALC) sample are successful. This method may be used to different type of liquid crystal cell.

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