Patent ID: 6544602
Filing Date: 2003-04-08
Classification: C07D,C09K

Abstract:
A supertwist liquid-crystal display comprising:two outer plates which, together with a frame, form a cell, a nematic liquid-crystal mixture of positive dielectric anisotropy which is present in the cell, electrode layers with alignment layers on the insides of the outer plates, a pre-tilt angle between the longitudinal axis of the molecules at the surface of the outer plates and the outer plates of from about 0 degrees to 30 degrees, and a twist angle of the liquid-crystal mixture in the cell from alignment layer to alignment layer with a value of from 22.5 Â° to 600Â°, wherein the nematic liquid-crystal mixture comprises: a) 15-90% by weight of a liquid-crystalline component A consisting of one or more compounds having a dielectric anisotropy of greater than +1.5; b) 0-60% by weight of a liquid-crystalline component B consisting of one or more compounds having a dielectric anisotropy of between âˆ’1.5 and +1.5; c) 0-20% by weight of a liquid-crystalline component D consisting of one or more compounds having a dielectric anisotropy of below âˆ’1.5, and d) optionally, an optically active component C in such an amount that the ratio between the layer thickness (separation of the outer plates) and the natural pitch of the chiral nematic liquid-crystal mixture is from about 0.2 to 1.3, wherein the liquid-crystal mixture comprises at least one compound of the formula IA â€ƒin which Rais H or an alkyl group having 1 to 7 carbon atoms,Rbis an alkyl or alkoxy group having 1 to 10 carbon atoms or analkenyl or alkenyloxy group having 2 to 10 carbon atoms,andnis 0, 1 or 2,and simultaneously comprises at least one compound of the formulae IB1 to IB4: in whichRcis H or an alkyl group having 1 to 7 carbon atoms,Y1is H or F,andpis 0, 1 or 2.