Patent ID: 6753045
Filing Date: 2004-06-22
Classification: C09K

Abstract:
An STN liquid-crystal display havingtwo outer plates, which, together with a frame, form a cell, a nematic liquid-crystal mixture of positive dielectric anisotropy located in the cell, electrode layers with alignment layers on the insides 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 0 degree 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 between 100Â° and 600Â°, a nematic liquid-crystal mixture comprising a) 15-80% by weight of a liquid-crystalline component A consisting of one or more compounds having a dielectric anisotropy of greater than +1.5; b) 20-85% 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 component A comprises at least one compound of formula I in whichR1 is H or C1-12-alkyl, in which, one or two non-adjacent CH2 groups may be replaced by â€”Oâ€”, â€”CH&boxH;CHâ€”, â€”COâ€”, â€”OCOâ€” or â€”COOâ€” in such a way that O atoms are not linked directly to one another, and L1 is H or F, at least one compound of formula II in whichR2 and R3 are each independently H, halogen, â€”CN, â€”NCS, â€”SF5 or C1-12-alkyl in which one or two non-adjacent CH2 groups are optionally replaced by â€”Oâ€”, â€”CH&boxH;CHâ€”, â€”COâ€”, â€”OCOâ€” or â€”COOâ€” in such a way that O atoms are not linked directly to one another, and one or more H atoms are optionally replaced by halogen and/or â€”CN, and at least one compound of formula III in whichR4 is H or C1-12-alkyl, in which, one or two non-adjacent CH2 groups are optionally replaced by â€”Oâ€”, â€”CH&boxH;CHâ€”, â€”COâ€”, â€”OCOâ€” or â€”COOâ€” in such a way that O atoms are not linked directly to one another, X is â€”F, â€”Cl, â€”OCF3, â€”OCHF2, â€”OCHFCF3 or â€”OCF2CHFCF3, and L2 is H or F.