本論文研究了三種表面配向(無配向、水平配向和垂直配向)對膽固醇藍相液晶的光電特性影響。實驗結果發現表面配向處理對藍相液晶的溫寬確實會造成影響。其中以垂直配向的藍相液晶的溫寬最大，約有6.0 ℃。而無配向與水平配向的藍相液晶的溫寬都是約5.5℃。在低溫的降溫過程，表面配向處理會抑制藍相液晶的螺距隨溫度變化的現象。此外，表面配向處理可以使藍相液晶的晶格排列更整齊，如此一來可以降低藍相液晶的反射光散射現象。在垂直電場的作用下，藍相液晶的反射波長會有紅位移的現象。無配向的藍相液晶反射波長可調動約120 nm。水平配向的藍相液晶反射波長可調動90 nm。垂直配向的藍相液晶反射波長可調動110 nm。其中垂直配向處理有助於降低藍相液晶的操作電壓。

In this study, we researched three kinds of surface treatment (no surface treatment, homogeneous alignment (HA) and vertical alignment (VA)) effect for the optoelectronic properties of cholesteric blue phase liquid crystals (BPLCs). We demonstrate the surface treatments have influence on the temperature range of BPLCs. The VA-BPLC possesses the widest temperature range, about 6.0 ℃. The temperature range of both no surface treatment BPLC and HA-BPLC are about 5.5 ℃. In the process of cooling, the surface treatments will restrain the change of the pitch of BPLC. Besides, surface treatment will let the crystalline of BPLC shipshape, so that it can reduce the scattering of the reflection light of BPLC. In the vertical electric field, the reflection wavelength of BPLC will be red-shift when the applied voltage increased. The reflection wavelength of the HA-BPLC can be tuned about 90 nm. The reflection wavelength of the VA-BPLC can be tuned about 120 nm. We have demonstrated the treatment of vertical alignment will reduce the operating voltage of BPLC.

目錄
摘要……………………………………………………………………………………i
Abstract………………………………………………………………………………..ii
致謝…………………………………………………………………………...………iii
目錄……………………………………………………………...……………………iv
圖目錄………………………………….…………………………………………….vii
表目錄……………………………………………………………………..……….....ix

第一章 導論..............................................................................................1
1-1 前言.........................................................................................................................1
1-2 液晶簡介.................................................................................................................2
1-2.1 何謂液晶....................................................................................................2
1-2.2 液晶的起源..................................................................................................2
1-2.3 液晶的分類..................................................................................................3
1-3 藍相液晶( Blue phase liquid crystals, BPLC )………………………………….. 9
1-3.1 藍相液晶簡介..............................................................................................9
1-3.2 藍相液晶的旋光特性................................................................................11
1-3.3 藍相液晶的雙扭轉柱體結構與堆疊........................................................12
1-3.4 藍相液晶的布拉格反射與光學均向性...................................................13
1-3.5 藍相液晶的晶格缺陷與溫寬改善技術....................................................14
1-3.6 藍相液晶顯示器........................................................................................17
1-4 液晶光電元件常用的表面處理...........................................................................19



第二章 實驗相關理論............................................................................20
2-1 液晶的基本特性...................................................................................................20
2-1.1 液晶的折射率異向性( birefringence, Δn )………………………….20
2-1.2 液晶的介電異向性( dielectric anisotropic, Δε )……………………...…23
2-1.3 液晶的彈性連續體理論( elastic constant, kii )………………………….24
2-1.4 秩序參數( order parameter, S )………………………………………….25
2-2 藍相液晶的自由能理論.......................................................................................27
2-3 藍相液晶在電場中的相變...................................................................................28
2-4 藍相液晶的克爾效應( Kerr effect )…………………………………………….29
2-5 電場引致藍相液晶晶格大小伸縮.......................................................................30
2-6 Kossel diagram…………………………………………………………………...31

第三章 樣品製作與實驗量測.................................................................36
3-1 液晶盒樣品製作...................................................................................................36
3-1.1 藍相液晶配置............................................................................................36
3-1.2 液晶盒製流程............................................................................................36
3-2 實驗方法及量測...................................................................................................39
3-2.1 不同表面配向處理的藍相液晶的溫寬及反射波長量測……………....39
3-2.2 不同表面配向處理的藍相液晶在外加電場下的特性量測……………41






第四章 實驗結果與討論………………………….……………………42
4-1 無配向的藍相液晶盒樣品光電特性量測……………………………………...42
4-1.1 無配向的藍相液晶盒樣品的溫寬及反射波長量測……………………42
4-1.2 無配向的藍相液晶盒樣品在外加電壓下量測其反射波長的改變……..46
4-2 水平配向的藍相液晶盒樣品光電特性量測…………………………………...48
4-2.1 水平配向的藍相液晶盒樣品的溫寬及反射波長量測…………………48
4-2.2 水平配向的藍相液晶盒樣品在外加電壓下量測其反射波長的改變….52
4-3 垂直配向的藍相液晶盒樣品光電特性量測…………………………………...53
4-3.1 垂直配向的藍相液晶盒樣品的溫寬及反射波長量測…………………53
4-3.2 垂直配向的藍相液晶盒樣品在外加電壓下量測其反射波長的改變….57
4-4 三種表面配向的光電特性比較………………………………………………...58
4-4.1 三種表面配向對藍相液晶的溫寬影響…………………………………58
4-4.2 三種表面配向對藍相液晶反射光相對強度的影響…..………………………..58
4-4.3 三種表面配向對藍相液晶外加電場的影響……………………………60

第五章 結論……………………………………….……………………62

參考資料……………………………………….………………………..63

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