Patent ID: 6210760
Filing Date: 2001-04-03
Classification: C09K

Abstract:
A supertwist liquid crystal display havingtwo plane-parallel carrier plates which, with an edging, form a cell,a nematic liquid crystal mixture of positive dielectric anisotropy in the cell,electrode layers with superimposed orientation layers on the insides of the carrier plates,an angle of incidence between the longitudinal axis of the molecules on the surface of the carrier plates and the carrier plates of about 1 degree to 30 degrees anda twisting angle of the liquid crystal mixture in the cell from orientation layer to orientation layer, according to the amount, of between 180 and 360.degree., wherein the nematic liquid crystal mixture comprisesa) at least one component of group A, compounds of formula AIII to AVI: ##STR35##wherein R.sup.1 and R.sup.2 each independently of one another are each R and R is alkyl having 1-12 C atoms, wherein one or two non-adjacent CH.sub.2 groups can also be replaced by --O--, --CH.dbd.CH--, --CO--, --O--CO-- or --CO--O--,b) at least one component of group B1, compounds of the formula BI to BIV: ##STR36##wherein R.sup.1 and R.sup.2 each independently of one another have the meaning given for R, Z.sup.2 is --CH.sub.2 CH.sub.2 --, --CO--O--, --O--CO-- or a single bond and ##STR37##optionally at least one component of group B2, compounds of formula BV to BVII: ##STR38##wherein R.sup.1 has the meaning given for R,Z.sup.0 is --CH.sub.2 CH.sub.2 -- or a single bond, and ##STR39##wherein n is 1 to 9, X is CN or P and Y is H or F, optionally at least one component of group B3, compounds of the formulae BVIII and BIX: ##STR40##wherein R.sup.1 and R.sup.2 each independently of one another have the meaning given for R and ##STR41##c) 10-80% by weight of a liquid crystal component C, one or more compounds having a dielectric anisotropy of more than +1.5, andd) an optically active component E, in an amount such that the ratio between the layer thickness (separation of the plane-parallel carrier plates) and the natural pitch of the chiral nematic liquid crystal mixture is about 0.2 to 1.3,the nematic liquid crystal mixture having a nematic phase range of at least 60.degree. C., a viscosity of not more than 30 mPa.s and a dielectric anisotropy of at least +5, the dielectric anisotropies of the compounds and the parameters relating to the nematic liquid crystal mixture being based on a temperature of 20.degree. C.