Automatic, maskless, mircometer-scaled photoalignment technology and its applications

• Main Authors: Yueh-Chi Wu, 巫岳錡
• Other Authors: Tsung-Hsien Lin
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/37435288399473486514

碩士 === 國立中山大學 === 光電工程學系研究所 === 101 === In this study, we demonstrate an automatic, maskless, mircometer-scaled photo-alignment technology in the dye-doped liquid crystal (DDLC) cell. Generally, photo-alignment process needs to use the photo mask, but fabricating of photo mask costs much money and takes long time for academic research. So in this study, we proposed a photo-alignment technology using azo-dye-doped liquid crystal. The laser beam was focused to micrometer spot though the objective of microscope and automatically pattern the image by computer program. In the experiment, we injected the glass cell with azo-dye doped liquid crystal. To homogeneously align the liquid crystal, the cell is exposed to linearly polarized green laser first. Then, a green laser was focused on the sample by an object lens of a microscope to form a micrometer-scale pattern. The resolution of the pattern was determined by the focus length of the object lens. The alignment direction of each spot was determined by the angle of the polarizer, which was controlled by computer Matlab and LabVIEW programs. This multi-domain pattern is due to different alignment angle of the liquid crystal. When polarizer and analyzer is crossed and maked an angle of 45 degree to liquid crystal alignment, light can pass through the analyzer and appears bright. In this thesis, we study the influence of laser power, exposure time, temperature to micro-scale photo-alignment. This technology can not only align micrometer-scale pattern in a small area, but also align the liquid crystal in complex pattern. In addition, this technique can also be applied to other materials study or experiment.