隨著科技的日新月異，不論是最常見的顯示器，抑或是智慧型窗戶等產品，液晶光電科技的發展已成為人們日常生活中不可或缺的一環。此外，環保節能更是現今社會越來越重視的議題，因此多穩態液晶相關元件的研究便受到相當的重視。 本論文之研究以多穩態液晶元件及智慧窗戶為主，主要分為三個部分討論，第一部分為光控摻雜二色性染料之膽固醇液晶旋性之特性及電控其各相態之研究，利用偶氮苯手性分子受光影響改變其順反異構式之特性，使螺旋結構產生或左右旋性抵銷，藉此達到穿透不吸收及吸收不散射的兩種穩態，並透過施加交流電場，可切換其吸收散射態及吸收穿透態的灰階，故該元件具有光電控切換機制、永久穩態及高對比等特色，為一多穩態液晶光閥元件。第二部分為膽固醇液晶摻雜二色性染料之光電特性研究，以雙頻向列型液晶摻雜手性分子及二色性染料之特性為研究基礎，探討電控摻雜二色性染料之膽固醇液晶光電特性，並比較與White-Taylor cell之間的差異。第三部分為離子摻雜於向列型液晶之特性研究，以負型向列型液晶摻雜不同濃度之離子材料，觀察於外加不同電壓下，其離子流與介電異向性對液晶分子轉向之特性，並觀察其散射態及穿透態之差異。 ;With the rapid development of science and technology, the liquid crystal (LC) optoelectronic technology, including the techniques of displays, smart windows, and so on, has become an indispensable part in human’s daily life. In addition, environmental protection and energy conservation issues are more and more important over the recent decades. Therefore, the study of multi-stable LC components has been attracting substantial attention. The contents of the thesis include three topics about multi-stable LC light modulators and smart windows. The first topic is the study of the optically and electrically controllable electro-optical characteristics of dichroic dyes-doped cholesteric LCs. The photo-isomerization processes of the doped chiral azobenzene dopant play the most important role. On the basis of the photo- isomerization of the azobenzene between the cis- and trans-isomers, the helical twisting power (HTP) of the azobenzene chiral dopant can be tuned to achieve the bistable states, including the absorption state (no light scattering) and transparent state (no light scattering and absorption). Applying an AC electric field onto the LC device can switch the gray levels of its absorption-scattering states. The second topic is the study of electrically tunable electro-optical characteristics of dichroic dyes and chiral dopant-doped dual frequency nematic LCs, filled into two different kinds of LC cells. One LC cell was treated with homeotropic alignment layer, the other with homogeneous one (also known as White-Taylor cell). The last topic is the study of electrically switchable light scattering modes based on ion-doped nematic LCs. The electro-optical properties of nematic LCs (Δε<0) doped with different concentrations of ions with the application of electric filed were investigated. Additionally, the induced torques, resulting from the ion flow and the applied electric fields, to cause the rotation of LCs have also been discussed. The transparent and scattering modes of the described LC samples were compared with each other.
