The Effect of Siox Alignment Layer Thickness on the Switching of Smc* Bistable Liquid Crystal Devices

SiO x alignment layers have been shown to allow defect-free SmC ‫ء‬ devices with near optimum bistable orientation of the director. In this paper we investigate the effect of the thickness of this type of alignment layer on the required amplitude of an applied voltage pulse to cause bistable switching. The results of an experimental investigation and simple model are presented. We find that for thicker layers, the amplitude is controlled by the voltage drop across the alignment layers and by the effect of polar interactions between the liquid crystal ͑LC͒ and the alignment layers. For thin alignment layers the amplitude is weakly dependent on the details of the alignment layer, being more strongly influenced by the properties of the LC material.