Precise optical retardation measurement of nematic liquid crystal display using the phase-sensitive technique

A simple and novel optical heterodyne interferometer based on phase measurement was developed to measure liquid crystal cell parameters. Due to a common-path configuration utilized in this method, the Fabry-Perot effect and surface reflection could be eliminated in measurement, and a highly accurate measurement was expected. Based on the experimental data of the voltage-dependent phase change, the maximum phase retardation and cell gap of the nematic liquid crystal (NLC) layer was achieved experimentally. Experimental results agree well with theory.