Guest-host type liquid crystal composition and liquid crystal display

Abstract

The present liquid crystal composition is characterized by containing a dye of anthraquinone series represented by the following general formula (1) dissolved as a guest in a host liquid crystal: ##STR1## wherein R represents an alkyl group or a cycloalkyl group. The alkyl group or the cycloalkyl group of the dye of anthraquinone series includes those substituted by alkyl, hydroxyl, alkoxy, cycloalkyl, aryl, aryloxy, dialkylamino, or heterocyclic residue. Furthermore, the liquid crystal composition can contain two or more other kinds of the dye of anthraquinone series, or can be used in combination with other dyes. In the dye of anthraquinone series, the group --COOR at the 2-position and the group --CN at the 3-position are particularly important for realization of cyan color and a high S value. The dye of anthraquinone series is particularly effective for preparation of a black dye. The present liquid crystal display device is characterized by comprising a liquid crystal cell comprising two transparent juxtaposed substrate plates, transparent electrodes formed each on the opposite inner surfaces of the substrate plates, alignment films formed each on the opposite inner surfaces of the substrate plates to cover the transparent electrodes and align liquid crystal molecules, sealing members for keeping the two substrate plates at a predetermined distance, a liquid crystal composition containing the dye represented by the said general formula (1) being filled in the liquid crystal cell, and a light source being provided outside the liquid crystal cell.