電控及光控膽固醇液晶光閥特性與結構之研究;Studies of the structures and characteristics of optically and electrically switchable liquid crystal light shutters

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/80620

Title:	電控及光控膽固醇液晶光閥特性與結構之研究;Studies of the structures and characteristics of optically and electrically switchable liquid crystal light shutters
Authors:	黃濟棠;Huang, Chi-Tang
Contributors:	光電科學與工程學系
Keywords:	液晶;液晶光閥;擴增實境;聚合物網絡;智慧窗戶;liquid crystal;liquid crystal light shutter;augmented reality;polymer network;smart window
Date:	2019-08-20
Issue Date:	2019-09-03 14:48:31 (UTC+8)
Publisher:	國立中央大學
Abstract:	本論文的研究主要分為兩個部份，第一部份主要探討電控膽固醇液晶光閥之各種狀態與其對應之切換特性，其中藉由量測此光閥之電壓-穿透度曲線及透過偏光顯微鏡下的結構觀察，由此確立各狀態出現之電壓區間，此外，透過偏光顯微鏡所觀測的光學紋理圖，推論各狀態出現之原因及液晶分子排列方式，之後根據以上基礎，再由時間-穿透度曲線探究各狀態之切換過程。透過前述之研究成果，我們提出此電控膽固醇液晶光閥之五種結構，包含捲曲狀手紋結構、格狀手紋結構、多域狀手紋結構、電場引致手紋結構及垂直結構，將於第五章做完整之論述，且此五種結構之相互切換機制也由前述之時間-穿透度曲線確立。另外，本論文所架構之電控膽固醇液晶光閥存在三種穩態結構，且各狀態之穿透及散射程度也不盡相同，而透過此一光電特性，在本論文第六章亦提出將之應用於擴增實境之可能性。本論文的第二部份為光控膽固醇液晶光閥之研究，其中此部份之研究重點為探討聚合物網絡結構對於此光閥系統之相關影響，而此膽固醇液晶光閥透過摻雜於系統中之偶氮苯材料進行光致異構化反應及光致熱效應，以達到穿透度切換之效果，其中此光閥利用膽固醇液晶之焦錐態及各向同性態達到散射及穿透態間之切換；而針對偶氮苯材料對系統產生之效應，此部份將以溫控系統控制光閥之環境溫度，而在此條件下便可排除光致熱效應的影響，以單獨討論光致異構化反應對光閥系統帶來之影響，而後移除溫控系統，便可看出光致熱效應與光致異構化反應對光閥系統之影響程度。由於此光閥具有隨外在環境主動調節穿透度之能力，因此依據其光學特性，故於本論文第六章便提出將其應用於智慧窗戶之可能性，及其他未來可繼續研究之方向。 ;The research topics in this thesis include the following two sections. In the first section, the liquid crystal (LC) textures existing in the electrically controllable cholesteric LC (CLC) light shutter and the corresponding switching mechanism are discussed in detail. According to the measurements of transmittance versus applied voltage curves, and the images obtained by a polarized optical microscopy, the applied voltage range of each texture was elucidated. Furthermore, the switching mechanism was also proposed based on the obtained transmittance versus time curves. In addition, the detailed discussions described in Chapter 5 include the five kinds of LC textures, they are spiral-like fingerprint textures, grid-like fingerprint textures, multi-domain like fingerprint textures, field-induced fingerprint textures, and homeotropic textures. Moreover, the CLC light shutter mentioned in this thesis has three kinds of stable states, and the capabilities of transmission and scattering of each state are different. By using the mentioned opto-electronic characteristics, the proposed CLC light shutter has great potential for the application of the augmented reality (AR), which has also discussed in Chapter 6. The second section of the thesis is the study of optically controllable CLC light shutter. This study focuses on the influences of light shutter architecture resulted from the adopted polymer networks. The proposed CLC light shutter can be switched between transparent and scattering states under the illumination of UV lights. The switching mechanism of the CLC light shutter is based on the photo-isomerization effect and the photo-induced thermal effect of the doped push-pull azobenzene molecules. Owing to the above-mentioned effects, the scattering and transparent states of the CLC light shutter are successfully achieved by the focal conic textures and the isotropic state, respectively. In order to discuss the photo-isomerization effect individually, the temperature controller was utilized to maintain the ambient temperature and to remove the influence resulted by the photo-induced thermal effect on the CLC light shutter. The influences of photo-isomerization and photo-induced thermal effect of the light shutter can be observed simultaneously, resulted from the absence of the temperature controller. The proposed CLC light shutter has the capability to adjust transmittance automatically through the environmental variation, the possibility of applications of smart windows and future works according to its optical characteristics are also proposed in Chapter 6.
Appears in Collections:	[Graduate Institute of Optics and Photonics] Electronic Thesis & Dissertation

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