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研究生：	蔡佳琪 Tsai, Chia-Chi
論文名稱：	聚合物穩固摻雜手性分子之垂直結構液晶薄膜光電特性的研究 Studies of Electro-Optical characteristics of polymer-stabilized Chiral-Homeotropic Liquid Crystal Films
指導教授：	傅永貴 Fuh, Ying-Guey Andy
學位類別：	碩士 Master
系所名稱：	理學院 - 物理學系 Department of Physics
論文出版年：	2004
畢業學年度：	92
語文別：	中文
論文頁數：	126
中文關鍵詞：	液晶、垂直結構、手性分子、聚合物
外文關鍵詞：	liquid crystal, homeotropic, polymer, chiral
相關次數：	點閱：53 下載：2
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摻雜手性分子垂直結構的液晶薄膜(chiral-homeotropic liquid crystal films)在外加電壓之下變成似TN 結構，因此其也被稱之為『反向TN 模式』，因此其兼具垂直結構之優點即高對比度，良好暗態，也兼具TN 之優點-穿透率對於不同入射波長不敏感。但由於液晶反躍的作用(backflow effect)，造成反應時間非常長的缺點，本論文利用兩種不同方式，來控制聚合物枝條生長方向，藉著聚合物枝條對液晶的拉拔力量，來改善反應時間太長的缺點。實驗證實，聚合物穩固摻雜手性分子垂直結構液晶薄膜(polymer-stabilized
chiral-hoemotropic liquid crystal films 簡稱PSCHLC) 成功的阻止了backflow的發生，有效的縮短了反應時間；另外，我們也討論了PSCHLC cell 的色散(color dispersion)現象，實驗結果顯示，聚合物枝條對液晶的拉拔力量，讓PSCHLC 變成一個不完美的扭曲向列相(twisted nematic)液晶盒，使無法達到Gooch-Tarry 1st minimum的條件，所以消色散沒辦法達到跟CHLC(reverse TN)一樣好。

We study the Electro-Optical characteristics of polymer-stabilized Chiral-Homeotropic liquid Crystal Films. Various conditions to form polymer-networks are experimented. A Chiral-homeotropic cell becomes a TN cell under applying a suitable voltage. So, it is also called a reverse-TN mode. It presents a high contrast ratio and a good dark state like a VA cell, less color dispersion like a TN cell, but it possesses a drawback—slow response, because of the backflow effect incurred during the application of an external field. Experimental results obtained from our study show that the various types of polymer networks involved in the polymer-stabilized Chiral-Homeotropic liquid Crystal cell can reduce the backflow effect, and therefore, speed up the response time. The color dispersion caused by the polymer networks in a polymer-stabilized chiral-homeotropic liquid crystal cell is also experimented. The result shows that polymer networks result in an imperfect twisted nematic structure and it can not reach the Gooch-Tarry condition, so that the achromatic effect in the PSCHLC cell is not as good as a typical TN cell.

目     錄
英文摘要.....................................................................i
中文摘要....................................................................ii
致謝.....................................................................v
目錄........................................................................vi
圖表索引....................................................................ix
第一章	簡介
       1.1 液晶簡介..........................................................1
       1.2 液晶的分類........................................................2
       1.3 液晶物理
       1.3.1液晶的光學異向性.................................................6
       1.3.2 液晶的連續體彈性形變理論........................................9
       1.3.3 場對絕緣向列液晶的影響.........................................10
       1.4 溫度對向列項液晶的影響...........................................13

第二章	理論探討
       2.1 液晶流動簡介.....................................................16
       2-1.1 Twisted Nematic (TN) cell的backflow............................16
       2-1.2 Chiral-Homeotropic cell的backflow..............................17
       2-2 viscosity 對於液晶層flow的影響...................................21
       2-2.1 The six Leslie coefficients的特性..............................21
       2-2.2 Miesowicz (shear) coefficients and 
             Leslie coefficient of viscosity................................22
       2.3 Jones matrix.....................................................26
       2.4 光經過twisted-nematic liquid crystal cell的特性..................29
       2.5 Gooch-Tarry 1st Minimum..........................................32
       2.6 Chiral-Homeotropic Liquid Crystal (CHCL) Cell 介紹...............34
       2.7 Chiral-Homeotropic Liquid Crystal Cell的工作原理.................35
       2.8 反應時間的定義...................................................39
       2.9 π cell與反應時間................................................40
第三章     實驗準備
       3.1 樣品的製備流程....................................................46
       3.2 所使用材料的參數及製備條件........................................48
       3.3 實驗裝置..........................................................49
第四章     實驗結果與分析
       4.1 不同濃度的polymer，在不同電壓驅動之下，液晶backflow的現象之研究...50
       4.2 (I) 不加電壓，垂直(homeotropic)態Curing PSCHLC cell...............55

       4.3 實驗結論(I).......................................................72
       4.4 加電壓Curing PSCHLC cell..........................................75
       4.5實驗結論(II).......................................................87
       4.6 (III) Color dispersion的探討......................................91
       4.7實驗架構...........................................................94
       4.8實驗結果與討論(III)................................................95
第五章    總結與展望.........................................................97
參考文獻......................................................................A
                                    

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校外：2004-07-06公開

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