Study on dc and ac Switching Behavior in Liquid Crystal Displays with Polymer Boundaries using a 4-Component Circuit

Abstract

A 4-component circuit is proposed to study the electric behavior of liquid crystal displays with polymer boundaries accompanying dc and ac voltage application. Two series components C ₁ and R ₁ are introduced to represent the capacitance and dielectric relaxation of a polymer boundary. Another two parallel components, R ₀ and C ₀, are used to take into account the bulk effect of liquid crystal layer. Transient currents induced by three types of switching of an applied voltage, single step, triangular and rectangular waveforms, are explained theoretically and experimentally. The theoretical results are in excellent agreement with the data from experiments. These provide the measurement method for obtaining the 4 components in a cell assembly. It is found that the effective voltage which is applied only to the bulk is different from an external applied waveform.