臺灣博碩士論文加值系統

本文利用在液晶中添加自組織材料及偶氮染料製作出可電控之Fresnel透鏡。實驗中，我們使用雙面吸附方法搭配透鏡光罩以綠光照射樣本，因為自組織材料的特性會使液晶引致垂直排列，而偶氮染料在綠光照射後帶動液晶方向轉為平行入射偏振，使透鏡奇數區和偶數區形成水平排列和混合排列狀態，實驗結果顯示，可以利用入射偏振和電壓控制可使液晶透鏡有不同的聚焦效率，並可使入射圖案經過透鏡後會形成縮小或放大的成像，比起傳統固態透鏡有可調的聚焦效率和調控成像大小的功能。

In this paper, an electrically controllable Fresnel lens is made by adding self-organized materials and azo dyes into the liquid crystals (LCs). In the experiments, we used the double-sided adsorption method with the Fresnel lens mask to irradiate the sample by green light. Before the photoalignment, LC molecules are oriented vertically because of the characteristics of the self-organized materials. After the photoalignment, the adsorption of azo dyes guides LCs to parallel the polarization of green light. The odd-numbered area and even-numbered area of the lens give rise to a homogeneous alignment and a hybrid alignment LC orientation, respectively. The experimental results show that the change of incident polarization and the application of voltage can modulate the diffraction efficiency of Fresnel lens. The incident light pattern passes through the Fresnel lens will form a reduced or enlarged image. The fabricated LC Fresnel lens possess a tunable diffraction efficiency and the function of adjusting the size of the image, that is better compared with the traditional solid-state lens.

摘要.....................................................i
Abstract................................................ii
誌謝...................................................iii
目錄....................................................iv
表目錄.................................................vii
圖目錄................................................viii
符號說明.................................................x
第一章緒論...............................................1
第二章液晶簡介...........................................2
2.1液晶的起源...........................................2
2.2液晶的定義...........................................2
2.3液晶的分類...........................................3
2.3.1盤狀分子...........................................3
2.3.2棒狀分子...........................................4
2.4液晶物理..............................................7
2.4.1光學異向性..........................................7
2.4.2介電異向性.........................................11
2.4.3溫度的影響.........................................12
2.4.4連續彈性體理論.....................................13
2.4.5Freedericksz transition...........................14
第三章相關理論..........................................15
3.1液晶的相位延遲(Phase retardation)....................15
3.2菲涅耳區板(Fresnel zone plate)......................16
3.3自組織材料特性......................................21
3.4光引致染料轉動.......................................21
3.4.1正力矩效應(Positive torque effect).................22
3.4.2負力矩效應(Negative torque effect).................22
3.4.3吸附引致液晶排列...................................23
3.5溝槽理論.............................................24
第四章樣本製作與實驗架構................................25
4.1 材料介紹............................................25
4.1.1向列型液晶.........................................25
4.1.2十二氫氧基硬酯酸(12-hydroxy-stearic acid；HSA).....25
4.1.3偶氮染料：Methyl red...............................26
4.2樣本製作.............................................27
4.2.1材料配置...........................................27
4.2.2ITO玻璃清洗.......................................28
4.2.3樣本製造...........................................28
4.3實驗架構.............................................29
4.3.1樣本厚度量測架設...................................29
4.3.2染料吸附架設.......................................30
4.3.3偏振儀.............................................30
4.3.4電壓穿透度的量測...................................31
4.3.5聚焦效率的量測.....................................31
4.3.6聚焦點與偏振關係量測...............................32
第五章結果與討論........................................33
5.1Fresnel lens的液晶排列..............................33
5.2偏振儀和吸收光譜量測................................34
5.2.1偏振儀量測.........................................34
5.2.2吸收光譜量測.......................................37
5.3Fresnel lens光電特性................................38
5.3.1T-V curve量測.....................................38
5.3.2聚焦效率量測.......................................38
5.3.3偏振與聚焦效率關係.................................39
5.3.4反應時間...........................................39
5.3.5第一階聚焦處拍攝照片...............................40
第六章結論..............................................42
6.1總結.................................................42
6.2未來工作.............................................43
參考文獻................................................44
Extended Abstract.......................................45

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