Effect of alignment layer on V-shaped switching in a chiral smectic liquidcrystal

The influence of the alignment layer on V-shaped switching in thin homogene ous cells of a chiral smectic liquid crystal were studied by means of elect ro-optic and switching current measurements. Several polyimides with differ ent chemical structures were used as the alignment layer in thin homogeneou s cells; V-shaped switching was observed with some of them and W-shaped swi tching with others. It was also shown that the switching current constantly flows during the V-shaped transmittance change. In order to clarify this e ffect of the alignment layer on V-shaped switching, polyimide films with va rious polarity and thickness were examined. It is concluded that thick alig nment layers assist liquid crystal materials in realizing V-shaped switchin g, even if the materials are not ideal fbr this process.