||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.
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