臺灣博碩士論文加值系統

藉由架設一液晶元件之光電調變系統，我們展示了電控雙折射水平配向型(ECB-homogeneous)液晶盒當施加一正弦波電壓時，其輸出波形的振幅與偏移量會呈週期性的震盪，而且輸出頻率會呈現二倍或四倍於輸入頻率。對於此現象發生的成因，我們認為是液晶分子受輸入電壓及backflow效應的相互影響所致。為了驗證此觀點，我們使用LC3D模擬軟體來與實驗結果相互比對，並定性地說明此種現象的成因。

In this thesis, frequency modulations were demonstrated using a liquid crystal light shutter operated in the electric controlled birefringence mode. When the sinusoidal waves was applied to the LC cell, the output sinusoidal waveforms with double or quadratic frequency of the input signal were generated. Also, the output amplitudes and offsets exhibit periodic oscillations. The applied voltage and the backflow effect contribute to the observed phenomena, and the experimental results were compared and explained qualitatively with the simulation results.

第一章 簡介
1-1 前言………………………………………………………1
1-2 液晶簡介…………………………………………………2
1-2-1 何謂液晶 (Liquid Crystals)…………………………...2
1-2-2 液晶的分類…………………………………………….3
1-2-3 液晶在非顯示器領域上的應用………………………11
1-3 液晶的光電效應…………………………………………13
1-3-1 液晶的光學各方異向性 (Optical Anisotropy)…13
1-3-2 液晶的連續體彈性變形理論………………….18
第二章 理論
2-1 電控雙折射(ECB)效應…………………………………..19
2-2 液晶流動(backflow)效應簡介…………………….23
2-2-1 Baclflow簡介………………………………………….23
2-2-2 在Baclflow效應下之Rise Time與Fall Time……….24
2-3 應答時間(Response time)的定義………………………...26
第三章 實驗方法與流程
3-1 樣品的製作流程…………………………………………...27
3-2 所使用的液晶材料參數…………………………………...29
3-3 實驗裝置的架設…………………………………………30
3-4 實驗流程…………………………………………………31
3-5 實驗結果驗證……………………………………………32
第四章 實驗結果與分析模擬
4-1 外加電壓對頻率調變的影響……………………………33
4-1-1穿透率(偏移量)對外加電壓關係的探討與模擬…….36
4-1-2 頻率調變對外加電壓關係的探討與模擬……………41
4-1-3 二倍頻調變現象的探討與模擬………………………43
4-2操作頻率對調變器輸出特性的影響………….…49
4-3 四倍頻偏壓點對樣品厚度的關係……………...54
第五章 總結……………………………………………………..55
參考文獻…………………………………………………….57

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