A Measurement System for the Phase Retardation of Liquid Crystal Particles Under an Electric Field Effect

The optical characteristics of LCDs, e.g. their brightness, contrast ratio and response time, are sensitive to the structural parameters of the liquid crystal cells. This study develops a phase retardation measurement system using a laser interferometer, a liquid crystal cell and a function generator. When the liquid crystal particles are subjected to an electric field effect, their orientation changes, causing a corresponding change in the optical path length through the liquid crystal cell. By relating the optical path length difference to the change in the particle angle, the relationship between the phase retardation and the applied voltage can be obtained