Influences of Surface Properties of Polyimide Films on Liquid Crystal Pretilt Angles

• Main Authors: Lin,Chien-Hung, 林建宏
• Other Authors: Jeng, Shie-Chang
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/97124396930937317445

碩士 === 國立交通大學 === 光電科技學程 === 100 === Polyimide (PI) has been widely applied in the LC displays (LCDs) industry as the alignment layers to align LC molecules in a certain orientation and conformation with a specific pretilt angle. The pretilt angle is very important and required for LC devices to obtain a defect-free alignment and also to improve their electro-optical performance. In current manufacture process, the pretilt angle is determined after the LC panel is assembled. Therefore, the LC panel with non-qualified pretilt angle can not be detected in advance to reduce the cost. The purpose of this work is to study the relationship between LC pretilt angle and the surface properties of PI in order to determine the pretilt angle just after the process of mechanically buffed PI. The results showed that the pretilt angle decreased with the rubbing depth, and the relationship strongly depended on the PI materials. By measuring the surface energy of the buffed PIs, it was observed that some PI materials showed the dependence between the pretilt angle and the polarity.