Liquid crystal display device

Abstract

Abstract PURPOSE:To maintain the brightness of a display surface and to increase contrast in a storage type liquid crystal display device by superposing two liquid crystal layers consisting essentially of nematic liquid crystals exhibiting hysteresis characteristics and cholesteric liquid crystals on top and bottom. CONSTITUTION:The liquid crystals 18, 19 obtained by adding cholesteric liquid crystals to mixed liquid crystals of an (n) type nematic liquid crystal and a (p) type nematic liquid crystal are used as the liquid crystals having a storage effect utilizing hysteresis characteristics. Such cells are superposed on top and bottom. The cells have transparent substrates 15, 16, 17 and transparent electrodes 11, 12 and 13, 14 which face to each other are disposed on the transparent substrates. While no voltage is applied, the liquid crystals 18, 19 are transparent and the light transmittances thereof are 80% and the brightness of conventional devices is maintained. When voltage is applied, they assume a light scattering state and the light transmittances drop to 25%. The contrast ratio is increased to 80%/25%, that is, 3.2, which is about 2 times higher than that in the prior art.

Inventors

• 👤 Niro Motoki

Bibliographic Details