| Summary: | 碩士 === 國立臺北科技大學 === 光電工程系研究所 === 99 === The twisted-nematic (TN) mode display has been widely used, because of its simple fabrication process, high transmittance and week color dispersion characteristics. However, the low contrast ratio and asymmetric viewing angle characteristic limits the development of the TN mode. So, we adopt the vertical alignment to improve the shortcomings of TN mode.
In this study, we have simulated the optical properties of twisted vertical alignment mode (TVA mode) by using simulation software (Techwiz). Moreover, we compared the experimental results with the simulation result.
In the experiment, first, we mixed chiral and liquid crystal in order to achieve the desired angle of liquid crystal molecules. Second, we mixed monomer and polyimide. Then, the TVA cell was exposed by UV light locally with applying electric field at the same time to control the pretilt angle and symmetry center.
We found that the vertical alignment (VA) can make better initial dark state and can improve the TN mode contrast. In addition, the local exposure can improve the stability of the symmetry center of the TVA cell and can improve the viewing angle characteristic of TN mode.
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