Simple method for measuring the high pretilt angle of nematic liquid crystals

Pretilt angle measurable by using the conventional crystal rotation method is limited to about 0degrees-20degrees and 70degrees-90degrees. We propose a method by which we can measure the pretilt angle by using the crystal rotation method even if the pretilt angle is between 20degrees and 70degrees. In this method, the determination of a pretilt angle is achieved by finding the rotation angles where transmittances are maximum and minimum in the periodic transmittance characteristics obtained with the variation of rotation angle. (C) 2003 American Institute of Physics.