Patent ID: 6531194
Filing Date: 2003-03-11
Classification: C09K

Abstract:
A supertwist liquid-crystal display comprisingtwo outer plates which, together with a frame, form a cell, a nematic liquid-crystal mixture of positive dielectric anisotropy present in said cell, electrode layers with alignment layers on the insides of said outer plates, a pretilt angle between the longitudinal axis of the molecules at the surface of said outer plates and said outer plates of 0 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 22.5Â° to 600Â°, and said nematic liquid-crystal mixture comprises a) 0-60% by weight of a liquid-crystalline component A comprising one or more compounds having a dielectric anisotropy of greater than +1.5; b) 0-60% by weight of a liquid-crystalline component B comprising 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 comprising one or more compounds having a dielectric anisotropy of below âˆ’1.5; and d) optionally an optically active component C in an amount whereby the ratio between the layer thickness (separation of the outer plates) and the natural pitch of the resultant chiral nematic liquid-crystal mixture is 0.2 to 1.3, wherein liquid-crystal mixture contains at least one compound of formula IA in whichRa is H or an alkyl group having 1 to 7 carbon atoms, and Rb is an alkyl or alkoxy group having 1 to 10 carbon atoms and at least one compound of formula IB, and, optionally, at least one compound of formula IC whereinRc is H or an alkyl group having 1 to 7 carbon atoms, Rd is F, OCF3, OCHF2, an alkyl or alkoxy group having 1 to 7 carbon atoms or an alkenyl group having 2 to 7 carbon atoms, Re is an alkyl or alkoxy group having 1 to 10 carbon atoms or an alkenyl or alkenyloxy group having 2 to 10 carbon atoms, Y1 to Y4 are each, independently of one another, H or F, q is 0 or 1, and p is 0, 1 or 2.