Patent ID: 6514579
Filing Date: 2003-02-04
Classification: C07C,C09K

Abstract:
A TN or STN liquid crystal display comprisingtwo substrates which, together with an edging, form a cell, contained in the cell, a nematic liquid crystal mixture having positive dielectric anisotropy, electrode layers having alignment layers on the insides of the substrates, a pre-tilt angle between the longitudinal axis of the molecules at the surface of the substrates and the substrates of from 0 degrees to 30 degrees, and a twist angle of the liquid crystal mixture in the cell which, from alignment layer to alignment layer, amounts to between 22.5Â° and 600Â°, wherein the nematic liquid crystal mixture comprises a) 20-90 wt % of a liquid-crystalline component A, consisting of one or more compounds having a dielectric anisotropy of more than +1.5; b) 10-80 wt % 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 wt % of a liquid-crystalline component C, consisting of one or more compounds having a dielectric anisotropy of less than âˆ’1.5 and d) an optically active component D in such an amount that the ratio between layer thickness (spacing of the substrates) and natural pitch of the chiral nematic liquid crystal mixture is from about 0.2 to 1.3, wherein component A of the mixture comprises at least one compound of formula IA, â€ƒwhere R3 is an alkenyl group having from 2 to 7 C atoms, â€ƒand the mixture comprises at least one alkynyl-bonded compound of formula IB, â€ƒwhere R1 and R2 each, independently of one another, are an alkyl, alkoxy or alkenyl group having from 1 to 12 C atoms, with the additional option of 1 or 2 non-adjacent CH2 groups being 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 L is H or F.