Electro-optical liquid crystal display
AssigneeMerck Patent GmbH
InventorsKazuaki Tarumi, Brigitte Schuler, Matthias Bremer
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Abstract
An electro-optical liquid crystal display with active-matrix addressing, in which the liquid-crystal layer has a homeotropic or tilted homeotropic alignment in the switched-off state and which contains a liquid-crystalline medium of negative dielectric anisotropy. The medium contains A) 30-70% by weight of two or more compounds of the formula I ##STR1## and B) 20-50% by weight of two or more compounds of the formula II ##STR2## in which R.sup.1, R.sup.2, ##STR3## and m are as defined in claim 1. The displays are particularly capable of operation based on the vertically-aligned cholesteric or nematic (VAC or VAN) effect.
Claims12
An electro-optical liquid-crystal display with active-matrix addressing, which is capable of operation by active-matrix addressing based on the vertically aligned cholesteric effect or the vertically aligned nematic effect, having a liquid-crystal layer with a homeotropic or tilted homeotropic alignment in the switched-off state and containing a liquid-crystalline medium of negative dielectric anisotropy, wherein the medium consists essentially of:
- A) 30-70% by weight of two or more compounds of the formula I ##STR21## in which R.sup.1 and R.sup.2 are each, independently of one another, an alkyl or alkenyl radical having 1 to 15 carbon atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or monosubstituted to perhalo-substituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals are optionally independently of one another, replaced by --O--, --S--, --CO--, --CO--O--, --O--CO-- or --OCO--O in such a way that --O-- atoms are not linked to one another, ##STR22## is a trans-1,4-cyclohexylene radical, in which one or more non-adjacent CH.sub.2 groups are optionally replaced by --O-- and/or --S--, or a 1,4-phenylene radical, in which one or two CH groups are optionally replaced by --N--, and m is 1, 2 or 3, and
- B) 20-50% by weight of two or more compounds of the formula II ##STR23## in which R.sup.1, R.sup.2, ##STR24## and m are as defined for the formula I.
A liquid-crystalline medium consisting essentially of:
- A) 30-70% by weight of two or more compounds of the formula I ##STR29## in which R.sup.1 and R.sup.2 are each, independently of one another, an alkyl or alkenyl radical having 1 to 15 carbon atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or monosubstituted to perhalo-substituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals are optionally independently of one another, replaced by --O--, --S--, --CO--, --CO--O--, --O--CO-- or --OCO--O in such a way that --O-- atoms are not linked to one another, ##STR30## is a trans-1,4-cyclohexylene radical, in which one or more non-adjacent CH.sub.2 groups are optionally replaced by --O-- and/or --S--, or a 1,4-phenylene radical, in which one or two CH groups are optionally replaced by --N--, and m is 1, 2 or 3,
- B) 20-50% by weight of two or more compounds of the formula II ##STR31## in which R.sup.1, R.sup.2, ##STR32## and m are as defined for the formula I, and C) one or more compounds of the formula III ##STR33## in which R.sup.1 and R.sup.2 are as defined for formula I.
An electro-optical liquid-crystal display with active-matrix addressing, having a liquid-crystal layer with a homeotropic or tilted homeotropic alignment in the switched-off state and containing a liquid-crystalline medium of negative dielectric anisotropy, wherein the medium consists essentially of:
- A) 30-70% by weight of two or more compounds of the formula I ##STR34## in which R.sup.1 and R.sup.2 are each, independently of one another, an alkyl or alkenyl radical having 1 to 15 carbon atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or monosubstituted to perhalo-substituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals are optionally independently of one another, replaced by --O--, --S--, --CO--, --CO--O--, --O--CO-- or --OCO--O in such a way that --O-- atoms are not linked to one another, ##STR35## is a trans-1,4-cyclohexylene radical, in which one or more non-adjacent CH.sub.2 groups are optionally replaced by --O-- and/or --S--, or a 1,4-phenylene radical, in which one or two CH groups are optionally replaced by --N--, and m is 1, 2 or 3,
- B) 20-50% by weight of two or more compounds of the formula II ##STR36## in which R.sup.1, R.sup.2, ##STR37## and m are as defined for the formula I, and C) one or more compounds of the formula III ##STR38## in which R.sup.1 and R.sup.2 are as defined for the formula I.
Dependencies are inferred from the claim text.