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博碩士論文 etd-0808116-122939 詳細資訊
Title page for etd-0808116-122939
論文名稱
Title
橫向電場切換三穩態膽固醇液晶之研究與應用
Study of tristable cholesteric liquid crystal in multi-electrode driving system
系所名稱
Department
畢業學年期
Year, semester
語文別
Language
學位類別
Degree
頁數
Number of pages
76
研究生
Author
指導教授
Advisor
召集委員
Convenor
口試委員
Advisory Committee
口試日期
Date of Exam
2016-08-22
繳交日期
Date of Submission
2016-09-08
關鍵字
Keywords
膽固醇液晶、三穩態、IPS電極、零能耗智慧型節能窗
in-plane switching, energy-saving, smart window, multi-electrode system, tri-stable cholesteric liquid crystal
統計
Statistics
本論文已被瀏覽 5684 次,被下載 116
The thesis/dissertation has been browsed 5684 times, has been downloaded 116 times.
中文摘要
隨著科技發展日新月異,為了使人類生活更加便利,業界持續研發許多自動化的電器用品,然而也導致人類對能源的需求亦日趨增加,使地球上的能源面臨即將浩劫的窘境,因此,除了制訂能源政策之外,各領域的專家學者亦嘗試研發具備節能效果的應用技術,以減少能源消耗。我國經濟部能源局即針對各戶對用電量消耗做統計,發現大部分的用電消耗皆為室內照明設備以及空調系統,因此「智慧型節能窗」的概念亦逐漸成形。
液晶為可同時控制光場與電場的良好媒介,藉由施加一定外加場即可改變液晶分子的排列結構,進而達到對光場的調控。膽固醇液晶為折射率週期分布的螺旋結構,在不同螺距和螺旋軸排列下,具有不同的光學特性,一般而言,膽固醇液晶存在兩個不同排列結構的穩態 [1, 2],分別為螺旋軸垂直基板排列的 Planar texture 、排列結構散亂的 Focal conic texture,前者具有光反射的光學特性,後者具有光散射的光學特性。除此之外,透過施加特定條件的外加電場,如低頻電場擾動或橫向電場,亦可將膽固醇液晶排列至螺旋軸平行基板,進而形成 Uniform lying helix (ULH) texture,搭配弱配向的邊界條件則可使此結構成為穩態;除此之外,由於此結構可視為單光軸晶體的光學特性,且光軸方向平行玻璃基板,因此為光穿透態。
先前論文針對膽固醇液晶在 Full ITO 系統下進行三個穩態的切換,使用低頻電場擾動或是邊界週期性凹槽設計,使能夠穩定存在此三種結構,然而,由於在 Full ITO 系統下,需同時具有穩定三個穩態的邊界條件極為嚴苛,因此,本研究利用橫向電場引致的曲面電力線分布,進行三個穩態的切換,並且搭配弱配向邊界力的邊界條件,使能夠穩定存在。
本研究探討膽固醇液晶在 Planar texture、Focal conic texture、ULH texture 三個穩態在橫向電場的驅動機制下,並分析各種不同邊界條件,觀察在不同結構下膽固醇液晶的光學表現,更加了解膽固醇液晶在橫向電場效應下,形成不同結構的過程。
透過在這三個狀態之間的切換下,在顯示器方面可以製成反射式透明顯示器及透明手寫板,反射態作為顯示的色彩,散射態可作為暗態的顯示效果,透明態即可使環境的光穿透;除此之外,亦可應用於智慧窗,透明態即為一般窗戶的功能,反射態的波段可調控反射太陽輻射光與熱,亦可根據使用者的需求,主動式的調整太陽光的入射量,以調控室內照明及隱私保護性,更能節省室內照明及空調系統的能源消耗,且這三個狀態皆為穩態,即不需持續供給外加場即可維持在穩定的狀態,因此亦達到節能的效果。
Abstract
As technology improves every day, new developments are constantly infiltrating our lives which also results the energy consumption increase. Therefore, energy consumption is the difficulty we just encounter. Experts and scholars do research to achieve “energy saving and carbon reduction”. Bureau of Energy, Ministry of Economic Affairs, do statistical analysis about electrical energy use. According to the statistics, domestic use and commercial use are the main reason for energy consumption, most of which are from indoor light device and air conditioner. As a result, “Smart energy saving window” is gradually raised.
Liquid crystal is a good medium which can also control the light field and electric field. By applying a certain field, the arrangement of liquid crystal molecules would be changed which can control the light field. Cholesteric liquid crystal has the optical properties of reflection, scattering, transmission and characteristics of bistability [1, 2]. Additionally, cholesteric liquid crystal can be tri-stable under special boundary conditions. Planar texture can reflect the certain polarized light because of its periodic spiral structure. Focal conic texture can scatter the incident light because of its mismatch of refractive index. ULH texture is just like a uniaxial crystal which has optically birefringence.
According to previous papers, ULH texture can be driven by applying electric field with low frequency and stable in full ITO system with weak alignment. Periodic notch on substrate is also can form ULH texture. In addition, in-plane switching can drive ULH texture because of its curve electric field line. However, the former two conditions which can stabilize ULH texture is too limited. As a result, in this study, we drive these three texture by in-plane switching and understand the driving mechanism.
In display, this tri-stable mode can be applied for reflective transparent display and transparent writing board. In addition, it can be also use for smart window. These three stable states can achieve “energy saving and carbon reduction”.
目次 Table of Contents
論文審定書...........................................................i
摘要................................................................ii
目錄................................................................vi
圖表索引..........................................................viii
第一章 液晶簡介......................................................1
1-1 液晶 (Liquid Crystals) 簡介......................................1
1-1.1 何謂液晶.....................................................1
1-1.2 液晶的分類...................................................3
1-1.3 液晶的物理特性...............................................5
1-2 膽固醇液晶 (Cholesteric Liquid Crystals) 簡介....................10
1-2.1 膽固醇液晶結構介紹及光學特性................................10
1-3 膽固醇液晶雙穩態與三穩態驅動機制................................14
1-3.1 膽固醇液晶膽固醇液晶雙穩態驅動..............................14
1-3.2 膽固醇液晶三穩態驅動........................................15
1-3.3 橫向電場驅動三穩態膽固醇液晶之驅動原理......................20
第二章 實驗方法與過程...............................................25
2-1 材料介紹及實驗樣品製作..........................................25
2-2 多電極元件及橫向電場 (In-Plane Switching, IPS) 效應簡介.........26
2-3 量測架構介紹....................................................28
2-3.1 表面形貌觀察與分析..........................................28
2-3.2 穿透頻譜 (Optical spectrum) 以及穩態穿透度對電壓曲線之量測...29
第三章 實驗結果與討論...............................................30
3-1 Full ITO系統切換膽固醇液晶之結果................................30
3-2 橫向電場 (double-sided IPS) 切換三穩態膽固醇液晶之結果..........35
3-2.1 ULH texture的驅動機制.......................................35
3-2.2 Focal conic texture的驅動機制...............................46
3-2.3 Planar texture的驅動機制....................................52
3-3 三穩態膽固醇液晶元件特性........................................55
第四章 結論與未來展望...............................................61
參考文獻
參考文獻 References
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