Addressing device and method for rapid video response in a bistable liquid crystal display

摘要

A front-lit, non-gray scale liquid crystal display device (10) including a polymer stabilized cholesteric liquid crystalline material has two optical states stable in the absence of an electric field. In a reflecting optical state incident illumination is directly reflected by the liquid crystal, producing a light pixel. In a scattering optical state incident illumination is absorbed by a black surface on the rear of the display, producing a dark pixel. A method employing a plurality of display control signals having the same polarity and differing phase relationships permits the fast video response of the display, notwithstanding that the average time to switch from a scattering optical state to a reflecting optical state is about 30 milliseconds, requiring about fifteen seconds to update a typical 480-row liquid crystal display using conventional array sequencing techniques. Several routines are presented for determining when to update such a display for a variety of applications.