Patent ID: 8329058

Claim:
A chiral nematic liquid crystal photodisplay comprising: a liquid crystal layer including bistable cholesteric liquid crystal material, said liquid crystal material comprising nematic liquid crystal and at least one photosensitive chiral additive, wherein said photosensitive chiral additive changes a reflective wavelength of said liquid crystal layer at exposed regions at which addressing electromagnetic radiation is incident on said liquid crystal layer, regions of said liquid crystal layer that are not exposed to said addressing radiation being unexposed regions, thereby producing a planar image comprising said exposed regions and said unexposed regions both in planar textures of different reflective wavelengths; electrically conductive layers flanking said liquid crystal layer; and electrical addressing means for applying an electric field to said liquid crystal layer between said conductive layers, wherein said electrical addressing means applies the electric field at a magnitude that switches said liquid crystal material of either one of said exposed regions or said unexposed regions, but not the other, to a focal conic texture producing a fixed image that resists degradation with time.