LCD에 있어서의 네마틱 액정과 프리틸트각의 발생과의 관계

Relationship of the pretill angle and nematic liquid crystals on LCD

In this study, the effect of the crystallinity of polyimide (Pl) and the birefringence of the nematic liquid crystal (NLC) for pretilt angle generation on rubbed PI surface containing thiophenylene moieties has been demonstrated. The induced optical retardation produced in rubbed Pl surfaces decreases on increasing the imidization temperature. We suggest that the pretilt angle of 4-cyano-4'-n-pentybiphenyl (5CB) depends on the crystallinity of the rubbed Pl. The order of pretilt angle in NLCs is 5CB>PCH5$\geq$CCH5 at rubbing strength(RS)=150mm (medium rubbing) on rubbed PI surfaces. We suggest that on rubbed Pl surfaces the pretilt angle increases with increasing number of phenylrings in the NLC core.