Evaluation of Pretilt Angle and Polar Anchoring Strength of Amorphous Alignment Liquid Crystal Display from Capacitance Versus Applied Voltage Measurement

The pretilt angle and the anchoring strength are important parameters in liquid crystal displays (LCDs). However, in the case of amorphous LCDs (a-LCDs), it is difficult to evaluate these parameters by means of conventional measurement method due to non-uniformity of the LC directors. In this paper, we report the simultaneous evaluation method of the pretilt angle and the polar angle anchoring strength of a-LCDs by fitting the theoretical values based on the elastic continuum theory to the data obtained by the measurement of capacitance versus applied voltage (C-V) characteristics. We evaluate the pretilt angle and the polar anchoring strength of a-LCD using the polyimide alignment films. We confirm the pretilt angle and the polar anchoring strength of a-LCD are strongly dependent on surface energy of the polyimide alignment film.