Analysis of Ion Behavior Affecting Voltage Holding Property of Liquid Crystal Displays

Abstract

A mechanism for the decay of charged voltage, which leads to the lowering of the voltage holding ratio of liquid crystal displays (LCDs), was proposed using a model for the behavior of ions in an LC layer. The proposed model was verified by experimental results using two LC cells of different LC materials. The decay of the charged voltage occurs with two decay components; one originates from the ions arriving at the surface of an alignment layer due to the application of pulsed voltage diffusing toward the LC layer, and the other originates from the ions in the LC layer moving toward the opposite surface and canceling the dielectric polarization of LC molecules during an open-circuit period. We found that the decay of the charged voltage increases with increasing density of ions arriving at the surface before the open-circuit period.