| abstract |
A guest-host liquid crystal display device is disclosed which undergoes a focalconic-homeotropic phase transition. The device has a guest-host material layer including (a) a nematic liquid crystal having a positive dielectric anisotropy, (b) an optically active material for putting the nematic liquid crystal in a cholesteric condition, and (c) a pleochroic dye, and has an electrode means for establishing an electric field in the material layer in order that the material layer undergoes the phase transition from the cholesteric condition to the homeotropic condition. Liquid crystal molecules in contact with the surface of the electrode are oriented with their longitudinal axes perpendicular to the electrode surface, with an orientation treatment carried out in the electrode surface or by an orientation film provided on the electrode surface. Thus, the material layer assumes the focalconic condition in the absence of the electric field. A chiralnematic compound is employed as the optically active material. |