臺灣博碩士論文加值系統

本研究主要目的在探討奈米粒子-多面體矽氧烷寡聚合物 (Polyhedral Oligomeric Silsequioxanes；POSS)所產生的垂直配向行為與特性，並將其運用在液晶微透鏡元件的研製與開發。實驗發現將POSS奈米粒子加熱熔融 (Melting)並進行配向，可以改善直接摻混入液晶的配向機制所衍生相關問題，提供液晶配向更好的方向性及穩定性。光電量測部分主要利用檢測相位、穿透率、電容與電壓相依性的關係來判定在外加電壓作用下，奈米粒子對液晶分子的轉動影響，其中包括有對比度、響應時間以及錨定能等特性分析。同時藉由改變不同POSS官能基種類與製程條件等參數，做為分析POSS對於液晶提供配向機制之研究。此外我們嘗試將POSS奈米材料引致垂直配向技術與微滴法應用在平面微透鏡元件的開發中，藉由相關實驗製作得到焦距可隨電壓改變的液晶微透鏡，並量測相關透鏡之特性與焦距對電壓相依性的關係。

In this thesis, we investigated the nanoparticles of polyhedral oligomeric silsesquioxane (POSS), which can induce vertical alignment (VA). In our experimental, POSS nanoparticles were spin-coated on the ITO substrates, as well as then melted and rubbed to improve the shortcomings of POSS/LC mixture directly injected into cell. This spin-coated and rubbed POSS films can improve the preferred direction and stability of the director profiles of nematic liquid c rystals under the applied voltage. The electric and optical properties were investigated using the dependence of the phase retardation, transmittance, and capacitance measurements on the applied voltages, respectively, which can provide the detailed information of the impacts of POSS on the voltage-induced reorientation of the liquid crystal molecules.
The analysis includes the contrast, response time and anchonring energy, which critically depend on the different process conditions. In this work, we apply the different functional group of POSS and various process conditions to investigate the nanoparticles-induced alignment mechanism of liquid crystals. Furthermore nanoparticles-induced vertical alignment (NIVA) of the nematic liquid crystals (LC) was proposed to make a tunable liquid-crystal flat microlens with hybrid-aligned nematic (HAN) mode, which was fabricated using micro-dropping technique. The spatially varying director orientation and the lenslike distribution of refractive index appears in the NIVA LC layer with concentric non-uniform distribution of the refractive index was then formed. The focus effect and its voltage-dependent focal length of this flat LC lens were observed.

目錄
摘要........................................................ I
ABSTRACT................................................... II
致謝...................................................... III
目錄....................................................... IV
圖目錄..................................................... VI
表目錄...................................................... X
第一章 緒論..................................................1
1.1可變焦微透鏡簡介..........................................1
1.2液晶微透鏡簡介............................................4
第二章 液晶材料與配向技術...................................13
2.1液晶的分類...............................................13
2.2液晶的光學異向性.........................................15
2.3液晶的連續體彈性形變理論與介電異方性.................... 17
2.4 液晶配向相關理論........................................19
2.4.1 液晶配向..............................................19
2.4.2液晶配向技術...........................................22
2.4.3 POSS奈米粒子的配向....................................23
第三章 元件製作與量測原理...................................26
3.1 POSS/液晶盒製備.........................................27
3.1.1實驗材料...............................................27
3.1.2 液晶盒樣品製作........................................28
3.2元件相關量測.............................................31
3.2.1 表面能量測............................................31
3.2.2 原子力顯微鏡之量測....................................33
3.2.3偏光顯微鏡觀察.........................................33
3.2.4 電容對電壓量測........................................33
3.2.5 穿透率對電壓量測......................................35
3.2.6相位差量測.............................................36
3.2.7錨定能量測.............................................37
3.3 液晶微透鏡元件製作與聚焦特性量測........................42
3.3.1液晶微透鏡元件製作.....................................42
3.3.2 微透鏡元件的特性量測..................................44
第四章 實驗結果與討論.......................................47
4.1 AFM與接觸角量測.........................................47
4.2偏光顯微鏡觀測...........................................53
4.5 液晶盒P-V與錨定能量測...................................63
4.6 POSS於液晶微透鏡上的應用................................65
4.6.1 POM圖觀察.............................................66
4.6.2 干涉環觀察與焦距-電壓量測.............................69
第五章 結論與未來展望.......................................73
5.1 結論....................................................73
5.2 未來展望................................................74
參考文獻....................................................76
附錄一：POSS編號與相關參數..................................82

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