Liquid-crystal medium
A liquid crystal medium having negative dielectric anisotropy and containing one or more compounds of formulae B and C and one or more compounds of formula G and the use thereof for an active-matrix display, in particular based on the VA, SA-VA, IPS, PS-IPS, FFS, PS-FFS, UB-FFS or PS-UB-FFS effect.
1. A liquid crystal (LC) medium having negative dielectric anisotropy and comprising
one or more compounds of formula C1 and one or more compounds of formula G
in which the individual radicals, on each occurrence identically or differently, and each, independently of one another, have the following meanings:
denotes
R 0 , R 1 and R 2 denote a straight chain alkyl or alkoxy radical having 1 to 15 C atoms or a branched alkyl or alkoxy radical having 3 to 15 C atoms, in which one or more CH 2 groups may each be replaced, independently of one another, by
—C≡C-, —CF 2 O-, —OCF 2 -, —CH═CH—, —O—, —CO—O— or —O-CO— in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen
X 0 denotes F, CI, CN, SF 5 , SCN, NCS, a halogenated alkyl radical, a halogenated alkenyl radical, a halogenated alkoxy radical or a halogenated alkenyloxy radical having 1 to 6 C atoms, and
Z 0 denotes a single bond, —C 2 H 4 -, —CH 2 O-, —CF 2 O-, or —CH═CH-;
and
one or more compounds selected from formulae ZK and DK
in which the individual radicals on each occurrence, identically or differently, have the following meanings:
denotes
denotes
denotes
and
R 3 and R 4 each, independently of one another, denote alkyl having 1 to 12 C atoms, in which one or two non-adjacent CH 2 groups may be replaced by —O—, —CH-CH—, —CO—, —O—CO— or —CO—O— in such a way that O atoms are not linked directly to one another,
Z y denotes —CH 2 CH 2 -, —CH═CH—, —CF 2 O-, —OCF 2 -, —CH 2 O—, —OCH 2 -, —COO—, —OCO-, —C 2 F 4 -, —CF═CF— or a single bond,
R 5 and R 6 each, independently of one another, denote alkyl having 1 to 12 C atoms, in which one or two non-adjacent CH 2 groups may be replaced by —O—, —CH═CH—, —CO—, —OCO— or —COO— in such a way that O atoms are not linked directly to one another, and
e denotes 1 or 2.
2. The LC medium according to claim 1 , further comprising one or more compounds of formula B
in which the individual radicals, on each occurrence identically or differently, and each, independently of one another, have the following meanings:
R 1 , R 2 denote a straight chain alkyl or alkoxy radical having 1 to 15 C atoms or a branched alkyl or alkoxy radical having 3 to 15 C atoms, in which one or more CH 2 groups may each be replaced, independently of one another, by
—C≡C—, —CF 2 O-, —OCF 2 -, —CH═CH—, —O—, —CO—O— or —O-CO— in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen,
L 1 , L 2 denote F or Cl, and
Y 1 denotes O, S or CH 2 O.
3. The LC medium according to claim 2 , wherein the one or more compounds of formula B are selected from the following formulae
wherein
R 1 and R 2 denote a straight chain alkyl or alkoxy radical having 1 to 15 C atoms or a branched alkyl or alkoxy radical having 3 to 15 C atoms, in which one or more CH 2 groups may each be replaced, independently of one another, by
—C≡C—, —CF 2 O-, —OCF 2 -, —CH═CH—, —O—, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen.
4. The LC medium according to claim 1 , which additionally comprises one or more compounds selected from compounds of formula C2
wherein
R 1 and R 2 denote a straight chain alkyl or alkoxy radical having 1 to 15 C atoms or a branched alkyl or alkoxy radical having 3 to 15 C atoms, in which one or more CH 2 groups may each be replaced, independently of one another, by
—C≡C—, —CF 2 O-, —OCF 2 -, —CH═CH—, —O—, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen.
5. The LC medium according to claim 1 , wherein the one or more compounds of formula G are selected from the following formulae
wherein
R 0 denote a straight chain alkyl or alkoxy radical having 1 to 15 C atoms or a branched alkyl or alkoxy radical having 3 to 15 C atoms, in which one or more CH 2 groups may each be replaced, independently of one another, by
—C≡C-, —CF 2 O-, —OCF 2 -, —CH-CH—, —O—, —CO—O— or —O-CO— in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen.
6. The LC medium according to claim 1 , which additionally comprises one or more compounds selected from formulae CY and PY:
in which the individual radicals have the following meanings:
a denotes 1 or 2,
b denotes 0 or 1,
denotes
R 1 and R 2 each, independently of one another, denote alkyl having 1 to 12 C atoms, in which one or two non-adjacent CH 2 groups may be replaced by —O—, —CH-CH—, —CO—, —O—CO— or —CO—O— in such a way that O atoms are not linked directly to one another,
Z x and Z y each, independently of one another, denotes —CH═CH—, —CH 2 O-, —OCH 2 -, —CF 2 O-, —OCF 2 -, —O—, —CH 2 -, —CH 2 CH 2 — or a single bond,
L 1-4 each, independently of one another, denote F, Cl, OCF 3 , CF 3 , CH 3 , CH 2 F, or CHF 2 , and
L 5 denotes H or CH 3 .
7. The LC medium according to claim 1 , which comprises one or more compounds selected from formula ZK and one or more compounds selected from formula DK.
8. The LC medium according to claim 1 , which additionally comprises one or more compounds selected from the following formulae
in which
alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, and
alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6° C. atoms.
9. The LC medium according to claim 1 , which additionally comprises one or more compounds of the following formula
in which the individual radicals, on each occurrence identically or differently, and each, independently of one another, have the following meaning
R 1 , R 2 each, independently of one another, denote alkyl having 1 to 12 C atoms, in which one or two non-adjacent CH 2 groups may be replaced by —O—, —CH═CH—, —CO—, —O—CO— or —CO—O— in such a way that O atoms are not linked directly to one another, and
L T1 -L T6 denote H, F or Cl, with at least one of L T1 to L T6 being F or Cl.
10. The LC medium according to claim 1 , wherein
R 5 and R 6 each, independently of one another, denote alkyl or alkoxy having 1 to 6 C atoms.
11. A liquid crystal display comprising the LC medium of claim 1 .
12. The LC display of claim 11 , which is a VA, SA-VA, IPS, PS-IPS, FFS, PS-FFS, UB-FFS or PS-UB-FFS display.
13. A process of preparing an LC medium according to claim 1 , comprising mixing one or more compounds of formula C1 with one or more compounds of formula G and one or more compounds selected from formulae ZK and DK, and optionally with further LC compounds and/or additives.