Electrooptical Study of an In-Plane Switching Mode Using a Uniaxial Medium Model

Abstract

A new modeling method using a uniaxial medium model has been proposed to obtain a simple and quantitative expression for the transmittance of an in-plane switching (IPS) mode. In this model, the effective birefringence ( Δ n eff ) and the apparent optic axis rotation angle (φ app ) are used instead of the original birefringence and the director profile, and Δ n eff changes when an electric field is applied to the IPS mode cell. The dependences of Δ n eff (measured as a retardation) and φ app on the applied voltage have been evaluated first by experiment. Δ n eff was reduced to 80% of the original value and φ app rotated 45° at the maximum transmittance ( T max ). It has been confirmed that the transmittance can be reproduced satisfactorily by employing the model's expression using the observed Δ n eff and φ app values. Theoretical simulation has also been executed and the results supported the experimental results. The simulation has also shown that both the Δ n eff – Δ n ratio and φ app at T max are almost constant and do not depend on either the cell gap or liquid-crystal properties. T max can be easily calculated using the uniaxial medium model.