Patent ID: 6017469
Filing Date: 2000-01-25
Classification: C07C,C09K

Abstract:
Supertwist liquid-crystal display containingtwo plane-parallel 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 superposed alignment layers on the inside of the outer plates,a tilt angle between the longitudinal axis of the molecules at the surface of the outer plates and the outer plates of from about 1 degree to 30 degrees, anda twist angle of the liquid-crystal mixture in the cell from alignment layer to alignment layer with a value of between 100 and 600.degree.,a nematic liquid-crystal mixture consisting ofa) 20-90% by weight of a liquid-crystalline component A consisting of one or more compounds having a dielectric anisotropy of greater than +1.5;b) 10-65% by weight of a liquid-crystalline component B consisting of one or more compounds having a dielectric anisotropy of between -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 -1.5, andd) an optically active component C in an amount such that the ratio between the layer thickness (separation of the plane-parallel outer plates) and the natural pitch of the chiral nematic liquid-crystal mixture is from about 0.2 to 1.3, whereincomponent B comprises at least one compound of the formula I ##STR238## in which ##STR239## R.sup.1 is an alkyl, alkoxy or alkenyl radical having 1 to 10 carbon atoms which is unsubstituted or monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, optionally one or more CH.sub.2 groups in this radical being replaced by --O--,R.sup.2 is (CH.sub.2).sub.n --CH.dbd.CH--R.sup.2 or (CH.sub.2).sub.n --CH.dbd.CH.sub.2, and, in the case where R=1, R.sup.2 is alternatively R.sup.a,R.sup.a is a straight-chain alkyl having 1-6 carbon atoms,n is 0-6,p is 0 or 1,r is 0, or 1 ands is 1 or 2.