臺灣博碩士論文加值系統

本論文主要研究光配向 (photo-alignment) 技術在染料摻雜液晶(dye-doped Liquid Crystal, DDLC)盒內造成多區(multi-domains)配向的情況，並利用多區配向進一步製作出一般市面光罩無法製作的複雜圖形。
以往利用光配向製作複雜圖形的液晶元件需要搭配光罩使用，但光罩的製作夾雜著許多困難的技術，同時也需要耗費大量的時間與開銷，而且研究用途的特殊圖樣光罩使用率並不高，因此在成本與效率的考量上，這裡提出直接將雷射光點縮小，然後利用點陣圖得概念，將所需要的配向自動化的配向在元件上。由於樣品上的每一個點都具有不同的液晶排列，此種多區配向是利用液晶不同排列的相位延遲(phase retardation)，在前後偏振片下造成光的不完全穿透，可以在圖形上產生視覺的灰階，並且製作出不同液晶排列方向微米等級的複雜圖形。
本實驗先將灌入偶氮染料與液晶的無配向樣本進行第一次全面式的光配向使背景均勻化，接著將綠光雷射導入顯微鏡聚焦，再切換不同物鏡並調整曝光時間決定光點曝照的大小。研究中探討樣本穿透度，分析聚焦點大小與樣本溫度、入射光功率、曝光時間，找出最佳化的微米光配向參數後，利用電腦程式Matlab語言以及LabVIEW程式，控制光的偏振方向及多維移動平台，達成自動化微米解析多區域光配向製程。
我們除了利用此技術應用在各種需要小區域的配向元件，更可以利用此材料的複寫特性，重複利用光配向進行所需的液晶排列方向。除此之外，此種技術也可以應用在其他的材料中進行各種不同的光寫入機制。

In this study, we demonstrate an automatic, maskless, mircometer-scaled photo-alignment technology in the dye-doped liquid crystal (DDLC) cell.
Generally, photo-alignment process needs to use the photo mask, but fabricating of photo mask costs much money and takes long time for academic research. So in this study, we proposed a photo-alignment technology using azo-dye-doped liquid crystal. The laser beam was focused to micrometer spot though the objective of microscope and automatically pattern the image by computer program.
In the experiment, we injected the glass cell with azo-dye doped liquid crystal. To homogeneously align the liquid crystal, the cell is exposed to linearly polarized green laser first. Then, a green laser was focused on the sample by an object lens of a microscope to form a micrometer-scale pattern. The resolution of the pattern was determined by the focus length of the object lens. The alignment direction of each spot was determined by the angle of the polarizer, which was controlled by computer Matlab and LabVIEW programs. This multi-domain pattern is due to different alignment angle of the liquid crystal. When polarizer and analyzer is crossed and maked an angle of 45 degree to liquid crystal alignment, light can pass through the analyzer and appears bright. In this thesis, we study the influence of laser power, exposure time, temperature to micro-scale photo-alignment.
This technology can not only align micrometer-scale pattern in a small area, but also align the liquid crystal in complex pattern. In addition, this technique can also be applied to other materials study or experiment.

論文審定書+i
誌謝+iii
中文摘要+vi
英文摘要+vii
目錄+viii
圖目錄+x
表目錄+xiv
第一章 序論+1
第二章 理論介紹+3
2.1 何謂液晶+3
2.2 液晶的分類+3
2.2.1 向列型液晶+5
2.2.2 膽固醇型液晶+6
2.2.3 層列型液晶+7
2.3液晶的物理特性+8
2.3.1 介電係數異向性+10
2.3.2 折射率異相性+11
2.3.3 彈性係數異相性+15
2.4 液晶的配向+16
2.4.1 溝槽理論+17
2.4.2 不同的光配向效應+17
2.4.3 光引致染料分子轉向效應+18
2.4.4 正力矩效應+18
2.4.5 負力矩效應+19
2.4.6 光激發偶氮染料同素異構化反應+19
2.4.7 吸附效應+20
2.5 聚焦原理+21
第三章 實驗方法與過程+24
3.1 材料介紹+24
3.1.1向列型液晶E7 +24
3.1.2 偶氮染料Methyl Red(MR)+25
3.2 實驗儀器+26
3.3 實驗方法+27
3.3.1 藥品調製+27
3.3.2 玻璃基板處理+27
3.3.3 液晶盒製作+28
3.3.4 液晶盒厚度量測+29
3.3.5 藥品填充+29
3.3.6 背景均勻化光配向+30
3.4 微米解析光配向+31
3.4.1 自動化微米光配向+31
3.4.2 偏振歸一化+33
3.4.3 微米多區域化+34
3.4.4 灰階校正法+34
第四章 結果與討論+35
4.1 樣本穿透度實際值與理論值比較+35
4.2 樣本厚度造成的干涉現象+42
4.3 入射光功率與聚焦點大小分析+47
4.4 曝光時間與聚焦點大小分析+50
4.5 樣本溫度與聚焦點大小分析+52
4.6 自動化微米解析製程+54
4.7 相位光柵製程+55
4.8 微米光配向複寫製程+57
4.9 微米多區域製程+58
第五章 總結與未來展望+60
參考文獻+62

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