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Liquid Crystal Bistable Displays

1985; Volume: 122; Issue: 1 Linguagem: Inglês

10.1080/00268948508074738

0026-8941

R. N. Thurston,

Photonic Crystals and Applications

Abstract Binstability implies storage of information, which means memory. The practical significance of bistability is that it eliminates the need to refresh, which is a major obstacle to matrix-addressed displays that have a large number of elements. We review displays based on bistable configurations of the director orientation. Two types of such displays are distinguished by whether the bistable configurations are topological distinct, requiring disclination motion in switching, or not. The disclination-free type can operate at low voltages of about 5V, whereas a high voltage of 100V or more is required for rapid switching by disclination motion. An example of the high voltage type is an electrically written, thermally erased display based on the topological distinct vertical and horizontal states. A 20 row by 40 column model has been demonstrated. Examples of the low voltage, disclination-free type are a cholesteric twist cell and a display based on bistable boundary layer configurations. The boundary layer display bistability is insensitive to variations in holding voltage, cell parameters, material properties, and temperature. Switching is simple: a short, low voltage dc pulse selects one or the other of the bistable states, depending on the polarity of the pulse.