title: Unique measurement of the parameters of a twisted-nematic liquid-crystal display.
abstract: The parameters of a twisted-nematic liquid-crystal display (TN-LCD) are measured with no ambiguity when we measure the intensity transmittance of a system that simply consists of a TN-LCD, two polarizers, a quarter-wave plate, and a monochromatic beam. First we show analytically that the director angle can have a 90 degree ambiguity and the twist angle of the liquid-crystal molecules a 180 degree ambiguity. Then we uniquely measure the parameters by fitting the theoretical predictions to the intensity transmittance measured with and without the quarter-wave plate and by using the quasi local-adiabatic condition. The birefringence of the TN-LCD is measured next as a function of the applied voltage. We design a phase spatial light modulator by using the measured parameters and measure the phase delay of the output beam to excellent agreement with the theoretical prediction.
authors.affiliation: School of Information and Communication Engineering, Sungkyunkwan University, Suwon, Kyong-kido, 440-746, South Korea.
authors.forename: Hyun
authors.initials: H
authors.lastname: Kim
authors.forename: Yeon H
authors.initials: YH
authors.lastname: Lee