Evaluation of Liquid Crystal Alignment Ability of Polyimide by Analyzing the Black State of Homogeneous Alignment Liquid Crystal Display

We evaluate precisely the light leakage from the black state of homogeneously aligned liquid crystal displays, putting emphasis on the molecular alignment ability of polyimide films. We clarify the optimal fabrication condition for polyimide materials to obtain a better black state. In addition, we investigate the effect of embedded dielectric nanoparticles in a polyimide material on the degree of light leakage. It is shown clearly that the degree of light leakage depends on the polyimide materials and its fabrication condition, whereas only a limited improvement is obtained by adding nanoparticles into the alignment layers.