Patent ID: 8470411

Claim:
A zenithal bistable liquid crystal device having two cell walls comprising: an alignment layer on a first cell wall which leads a liquid crystal material in contact with said alignment layer to adopt any one of two stable states which persist in the absence of an applied field, said two stable states being different from one another; and a polarizer, adjacent said first cell wall, polarizing light input to said device; wherein the alignment layer and the polarizer are configured such that the refractive index of the alignment layer substantially matches the apparent refractive index of the liquid crystal material in the vicinity of said alignment layer for light at normal incidence in both of said two stable states, and said matching condition exists in each of said two stable states whether the respective stable state is a defect state a non-defect state; wherein the refractive index of said alignment layer substantially matches the ordinary refractive index of the liquid crystal material.