Patent ID: 7670654

Claim:
A bistable liquid crystal display device comprising: two cell walls enclosing a layer of a nematic liquid crystal material having finely-divided solid particles dispersed therein; at least one electrode on each cell wall for applying an electric field across at least some of the liquid crystal material; a first surface alignment layer on an inner surface of one cell wall for inducing adjacent molecules of the liquid crystal material to adopt a first planar orientation in a first specified azimuthal direction, and a second surface alignment layer on an inner surface of the other cell wall for inducing adjacent molecules of the liquid crystal material to adopt a second planar orientation in a second specified azimuthal direction at an angle greater than 0° and less than 90° to the first planar orientation; wherein the liquid crystal material adopts a first stable homeoplanar alignment in response to a first pulse of a unidirectional electric field of suitable magnitude and duration via the electrodes and adopts a second stable homeoplanar alignment in response to a second pulse of opposite polarity to the first pulse, the first homeoplanar alignment being in a same azimuthal plane as the first planar orientation and the second homeoplanar alignment being in a same azimuthal plane as the second planar orientation.