The Study of Plasma Treated Alignment for Twisted Nematic Cells

• Main Authors: Yi-Fan Chen, 陳怡帆
• Other Authors: Huang-Ming Philip Chen
• Format: Others
• Language: en_US
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/28554021806814170933

碩士 === 國立交通大學 === 光電工程系所 === 96 === The liquid crystal alignment plays a very important role to the LCD’s quality significantly. The traditional alignment rubbing method has the problem of static electricity, dust contamination, and uniformity issue. Non-contact alignment method can improve these disadvantages. But in the non-contact alignment method, the photo alignment has the problem of poor alignment stability and low anchoring energy. Furthermore, the cost in ion beam alignment is expensive, the equipment is complicated, and has the problem of ion gun lifetime compared with the plasma beam alignment. As a result, plasma beam alignment is the best solution of theses possible candidates. In this thesis, plasma beam alignment will be selected for the alignment technique. The surface morphology, pretilt angle, electro-optic characteristics after plasma beam treatment will be investigated. We found that the plasma alignment prepared TN cell has light leakage at the dark state compared with rubbed PI alignment cell. Because of ion bombardment during plasma alignment process, the NEXAFS data suggested that the out of plane carbonyl groups have been damaged seriously. It might cause the reduction of polar anchoring energy, and influence the EO characteristics of LC cell. The oxygen post-treatment is adopted to repair the surface polar functional groups. The light leakage can be suppressed successfully for the TN cell with oxygen post-treatment.