Liquid crystal display device having controlled refractive index anisotropy of the liquid crystal layer and the retardation compensator plate

Abstract

The liquid crystal display device is composed of at least one optical retardation compensator plate(and) inserted between a liquid crystal display elementand polarizer platesand. The liquid crystal display elementis composed of a pair of electrode substratesandand a liquid crystal layersealed therebetween. The polarizer platesandflank the liquid crystal display element. The optical retardation compensator plate(and) has a negative refractive index anisotropy (n=n>n). The direction of a principal refractive index nparallel to the normal to the surface and the direction of either a principal refractive index nor nin the surface incline either clockwise or counterclockwise around the direction of the principal refractive index nor nin the surface. Moreover, either the pretilt angle formed by the orientation filmsandand the longer axes of liquid crystal molecules in the liquid crystal layer or the value of applied voltage for displaying halftone obtained by applying to the liquid crystal a voltage that is close to the threshold voltage for the liquid crystal is set within such a range that tone reversion does not occur in the opposite viewing direction when halftone is being displayed.