摩擦的聚酰亚胺层上液晶分子排列的研究

Study of Liquid Crystal Molecular Alignment by Rubbed Polyimide Layers

本文用晶体旋转法测定预倾角,研究了聚酰亚胺材料及处理工艺对预倾角的影响.研究结果表明,延长聚酰亚胺固化时间,可提高预倾角,并得到最大预倾角为6.O°.提高聚酰亚胺固化温度、自然退火、采用强摩擦等可以提高预倾角.实际封盒组装工艺使预倾角有所降低.相对而言,紫外光固化对预倾角影响较小.高温存放,使得预倾角减小.利用液晶分子与聚酰亚胺分子的极性基团间的相互作用模型可以解释上述实验结果.

Liquid crystals display on twisted effect requires a tilt angle between liquid crystal molecules and the surface of the substrat to avoid the formation of a striped domain texture in liguid crystal's cell. The pretilt angle was measared by the crystal rotation method. Extended polyimide cure time have found to increase the pretilt angle of certain rubbed polyimide alignment layers to 6.0°.The pretilt angles increase with increasing polyimide cure temperature and slowly annealing and strongly rubbing. On the contrary, the pretilt angles reduce by pro-cessescell required to assemble the cell and storage of under high temperature. UV exposure for cell relatively had less effect on the pretilt angle. The experimental results have been explained by the model for the genaration of the pretilt angle between LC molecules and rubbed polyimide films.