Measurement of Pretilt Angle and Cell Gap in Reflective Vertically Aligned Nematics

An experimental setup to measure the pretilt angle and cell gap in reflective VAN (vertically aligned nematic liquid crystals) has been developed. This setup, based on the rotation method, has been modified in order to measure simultaneously high pretilt angles in reflective cells along with the cell gap. The determination of the pretilt angle is achieved by finding the rotation angle for maximum and minimum transmittances.