JPS566219A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: To increase operating voltage margin and improve contrast by so orienting a liquid crystal that when the liquid crystal contacts substrate in the state not applied any electric field the long axis direction of liquid crystal molecules becomes parallel to the substrates at around room temperature and intersects diagonally with the plane of the substrates at high and low temperatures.

CONSTITUTION: In the twisted molecule orientation type liquid crystal display device, the liquid crystal is so oriented that, when on electric field is applied on the plane where the liquid crystal molecules 1 contact a substrate 2, the long axis direction 3 of the molecules become parallel to the substrate as shown in fig. (b) near at around room temperature (20°C) and at a high temperature (40°C) and a low temperature (0°), their tilt angle θ intersect diagonally with the substrate plane like figs. (a), (c), respectively. For that purpose the liquid crystal having alkoxy groups is contained in a suitable amount in the liquid crystal and SiO, SiO₂ are used for the orientation films, so that said orientation is accomplished by the mutual action of the alkoxy groups and the dipole moments of SiO, etc. In this way, the difference in the voltage to obtain 10% contrast at the lighting of each temperature owing to temperatures is decreased and the operating voltage margin is increased.

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