Incident angle dependence of pretilt angle in a cell with oblique non-polarized UV light irradiation on polymer surface

편광되지 않은 UV광을 폴리이미드막에 경사지게 조사한 경우의 액정셀에서의 조사각도가 프리틸트각에 미치는 영향

In this study, we investigated the generation of pretilt angle for nematic liquid crystal (NLC) in a cell with oblique non-polarized ultraviolet (UV) light irradiation on polyimide (PI) surfaces. It was found that the monodomain alignment of the NLC is obtained with an angle of incidence of $70{\sim}85^{\circ}$ on PI surface. We consider that the monodomain alignment of NLC is attributed to anisotropic dispersion force due to photo-depolymerization of polymer on PI surfaces. Also, pretilt angle of NLC is generated about $3^{\circ}$ with an angle of incidence of $70{\sim}75^{\circ}$. It is considered that the pretilt angle generation in NLC is attributed to interaction between the LC molecules and the polymer surfaces.