臺灣博碩士論文加值系統

本實驗將偶氮染料-甲基紅(methyl red; MR)及二氧化矽奈米粒子(R812)摻雜進液晶中並將其製作成混合排列的樣本(hybrid-aligned nematic cell；HAN cell)，實驗主要是觀察在光配向時外加直流電壓對樣本的影響，由於MR與R812都帶有負電，在照光時持續在照光側施以一個微弱的正向直流電壓，會讓MR與R812受電場影響而游到照光側，進而在結束光配向後有不同的液晶排列。實驗結果顯示光配向時無外加電壓，可以得到照光區為垂直排列，光配向時有0.8V的外加電壓時，可以得到導軸轉向接近90度的混合排列，光配向時有1.2V的外加電壓時，照光區液晶為原配向方向液晶排列，當光配向時的外加電壓達4V時，照光區的液晶又形成垂直排列。在無照光的區域，液晶皆是可藉由R812電泳動達到多穩態的排列。因此我們可以利用照光跟電壓來達到圖形化且具單穩態或多穩態的多種液晶不同排列，應用價值相當高。

In this experiment, the azo dye-methyl red (MR) and silicon nanoparticles (R812) were doped into liquid crystals (LCs) and made into a hybrid-aligned nematic cell (HAN cell).
In the experiments, the influence of the applied DC voltage on the sample during photo-alignment was studied. When a weak positive DC voltage was applied to the illumination side during photoalignment, MR and R812 molecules moved to the illuminated substrate because both MR and R812 are negatively charged. The combination of the effect from MR and R812 molecules on the substrate caused different LC arrangements.
The experimental results show that the LCs in the illumination area could be aligned vertically when no applied voltage was applied during photoalignment. With an applied voltage of 0.8 V during photoalignment, a HAN cell with the director axis turning close to 90 degrees can be obtained. An applied voltage of 1.2V during photoalignment caused a HAN cell with the director in the original alignment direction. When the voltage during the photo-alignment reached 4V, the LC in the illuminated area formed a vertical arrangement. In non-illuminated areas, the liquid crystals can be oriented in a multi-stable state by the electrophoresis effect of R812. Therefore, we can use the photoalignment and the voltage to achieve patterned and monostable or multi-stable LCs with various orientations. The application value of the experimental results is quite high.

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....5
2.4. 液晶物理....9
2.4.1. 光學異向性....9
2.4.2. 介電異向性....13
2.4.3. 溫度的影響....14
2.4.4. 連續彈性體理論....15
2.4.5. Freedericksz Transition....16
第三章 相關理論....17
3.1. 液晶的相位延遲(Phase Retardation)....17
3.2. 電泳動原理[21] 18
3.3. Helmholtz Electric Double Layer....19
3.4. Gouy-Chapman Electric Double Layer....20
3.5. 光引致染料轉動....21
3.5.1. 正力矩效應(Positive Torque Effect)....22
3.5.2. 負力矩效應(Negative Torque Effect)....22
3.5.3. 吸附引致液晶排列....23
3.6. 溝槽理論....24
3.7. 扭轉型液晶(Twisted nematic liquid crystal )....24
第四章 樣本製作與實驗架構....26
4.1. 材料介紹....26
4.1.1. 向列型液晶：E7....26
4.1.2. 二氧化矽奈米粒子：Aerosil®R812....26
4.1.3. 偶氮染料：Methyl Red....27
4.2. 樣本製作....28
4.2.1. 材料配置....28
4.2.2. Indium-Tin-Oxide (ITO)玻璃清洗....29
4.2.3. 垂直配向膜製作....29
4.2.4. 水平配向膜製作....30
4.2.5. E7摻雜R812的扭轉型(Twisted Nematic，TN)樣本製作....30
4.2.6. E7摻雜Methyl Red的雙水平樣本製作....30
4.2.7. E7摻雜R812與Methyl Red的混合排列樣本製作....31
4.3. 實驗架構....31
4.3.1. 染料吸附的架設....31
4.3.2. 穿透率量測(TV-curve)架構....32
4.3.3. 轉偏振量測架構....33
4.3.4. 液晶轉動方向量測....33
第五章 結果與討論....35
5.1. 矽奈米粒子摻雜液晶的雙穩態特性及應用....35
5.1.1. 矽奈米粒子摻雜液晶的雙穩態....35
5.1.2. 矽奈米粒子摻雜液晶的應用-相位延遲板與偏振轉換器....37
5.2. 外加電壓對偶氮染料於光配向時的影響....40
5.2.1. 外加電壓對偶氮染料摻雜液晶樣本的光配向影響....40
5.2.2. 外加電壓對矽奈米粒子與偶氮染料摻雜液晶樣本的光配向影響....41
5.3. 光配向過程中不同外加電壓大小的影響....43
5.3.1. 光配向過程未加電壓....43
5.3.2. 照光時加0.4V及0.8V的正直流電壓....46
5.3.3. 照光吸附時加1.2V及2V的正直流電壓....50
5.3.4. 矽奈米粒子與偶氮染料照光吸附時加3V及4V的正直流脈衝電壓....55
第六章 結論....61
參考文獻....62
Extended Abstract....64

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