臺灣博碩士論文加值系統

本文使用之液晶材料不需經過添加高分子材料的程序，只在液晶當中加入旋光性分子就可達到高溫寬的BPIII相態，利用旋光性分子的濃度變化調製出在涵蓋室溫的BPIII相態，並針對電場頻率與大小的變化，觀測BPIII在RGB不同色光下，水平電場液晶盒中光電特性的探討。實驗結果顯示，當電場頻率增加大時穿透光強會逐漸遞減，其原因並非介電消散現象(Dielectric dispersion)所造成的，另一方面藉由量測出RGB三種色光的光穿透率，計算出BPIII在不同場下所誘發出的複折射值，將其區分為兩階段的光電效應，在電場的平方小於100 V2/μm2時，誘發之複折射值為克爾效應(Kerr effect)所造成的；而在電場的平方大於100 V2/μm2時，誘發之複折射值可能為 Pockels effect或其他光電效應所造成的。

Here, room-temperature liquid-crystal BPIII can be obtained by adding chiral dopant only. The temperature range of BPIII can be wider than 25 K. Observation on the electro-optical characteristic of IPS-BPIII was done by controlling the strength and frequency of the external electric field. The experimental results showed that the light transmittance gradually decreases as increasing the frequency of electric field. However, that is not caused by the dielectric dispersion after confirming the frequency dependence dielectric constants of LC. Moreover, the field-dependence induced birefringence was calculated from the polarimetric measurement. When the square of the electric field was less than 100 V2/μm2 , the electric field induced birefringence can be explained by model of Kerr effect. However, when the square of the electric field was greater than 100 V2/μm2, the electric-field induced birefringence might be explained by Pockels effect or other electric-optical effect.

致謝辭…………………………………………………………………...….i
摘要……………………………………………………………………...…ii
Abstract………………………………………………………………...….iii
目次………………………………………………………………………..iv
圖目次……………………………………………………………………..vi
表目次……………………………………………………………...…......xii
第一章 緒論…………………………………………………………….1
1-1 液晶介紹………………………………………………………..1
1-2 藍相液晶…………………………………………………….....2
1-3 藍相相態判別法…………………………………………….....6
1-4 藍相液晶溫度之拓寬………………………………………....11
1-5 藍相液晶之光電效應…………………………………….…...13
1-6 論文研究動機…………………………………………….…...16
第二章 理論………………………………………………………...…18
2-1 液晶光學之非均向性質……………..………………….…….18
2-2 藍相液晶缺陷自由能理論(Defect theory)……………….…..24
2-3 霧狀藍相BPIII之形成理論…………………………………..27
2-4 藍相液晶之彎電效應(Flexoelectric effect)…………………..29
2-5 藍相液晶之 Pockles effect…………….………………......…32
2-6 藍相液晶之介電消散現象(Dielectric dispersion)…………....33
第三章 實驗架構…………………………………………………...…38
3-1 液晶盒的規格與藍相液晶的配置…………………………....38
3-2 測量水平電場下BPIII的光電特性…………………………..38
第四章 實驗結果與討論…………………………………………...…47
4-1 藍相液晶之相態鑑定………………………………………....47
4-2 討論IPS-BPIII光強與樣品參數及入射光波長之關係…..…52
4-3 IPS-BPIII樣品電光特性之遲滯效應與反應時間………….. 61
4-4 頻率對IPS-BPIII樣品電光特性之影響…………………..…68
4-5 討論電場頻率對IPS-BPIII電光特性影響之原因………..…75
第五章 結論……………………………………………………...……88
參考文獻……………………………………………………………...…..91

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