Analysis of ion transport in LC cells with asymmetric alignment layers

Abstract

The presence of impurity ions in liquid crystal displays has long been blamed for degrading of devices. We have investigated the behavior of ions in bulk of the liquid crystal (LC) and in the interface between the LC and the alignment layer, using electro-optical, electrochemical and ζ-potential measurements. We report the effect of impurity ions in Nematic LC cells with asymmetric alignment layers made by different process. When a symmetric external electric field is applied to a Nematic LC cell, the internal dc voltage is built up, and the flicker is observed. This is a possible cause for impurity ions being introduced by the applied electric field and disturbing the absorption-desorption equilibrium.