Liquid-crystalline medium
A liquid-crystalline medium which comprises at least one compound selected from the group of compounds of the formulae IA to IH, in which Z 1 denotes a single bond, —CH 2 CH 2 —, —CH═CH—, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —COO—, —OCO—, —C 2 F 4 —, —(CH 2 ) 4 —, —CHFCHF—, —CF 2 CH 2 —, —CH 2 CF 2 —, —C≡C—, —CF═CF—, —CH═CHCHO— or —CH 2 CF 2 O—, and the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PALC, FFS, PS-FFS, SA-VA, PS-IPS or IPS effect.
1. A liquid-crystalline medium comprising, at least one compound selected from the group of the compounds of the formulae IA to IH, and wherein the medium has a negative dielectric anisotropy, Δε:
in which
Z 1 denotes a single bond, —CH 2 CH 2 —, —CH═CH—, —CH 2 O—, —OCH 2 , —CF 2 O—, —OCF 2 —, —COO—, —OCO—, —C 2 F 4 —, —(CH 2 ) 4 —, —CHFCHF—, —CF 2 CH 2 —, —CH 2 CF 2 —, —CF═CF—, —CH═CHCHO— or —CH 2 CF 2 O—, with the proviso that Z 1 does not denote a single bond in either the compound of formula IA or the compound of formula IB.
2. The liquid-crystalline medium according to claim 1 , which comprises at least one compound of at least one of the following formulae:
3. The liquid-crystalline medium according to claim 1 , wherein the proportion of the compound(s) of the formulae IA to IH in the medium as a whole is 1-50% by weight.
4. The liquid-crystalline medium according to claim 1 , which additionally comprises one or more compounds selected from the group of the compounds of the formulae IIA, IIB and IIC,
in which
R 2A , R 2B and R 2C each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is un-substituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, where, in addition, one or more CH 2 groups in these radicals may be replaced by —O—, —S—,
—C≡C—, —CF 2 O—, —OCF 2 —, —OC—O— or —O—CO— i n such a way that O atoms are not linked directly to one another, a cyclopropyl ring, cyclobutyl ring or cyclopentyl ring,
L 1-4 each, independently of one another, denote F, Cl, CF 3 or CHF 2 ,
Z 2 and Z 2′ each, independently of one another, denote a single bond, —CH 2 CH 2 —, —CH═CH—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —O CH 2 —, —COO—, —OCO—, —C 2 F 4 —, —CF═CF—, —C≡C— or —CH═CHCH 2 O—,
p denotes 0, 1 or 2,
q denotes 0 or 1, and
v denotes 1 to 6.
5. The liquid-crystalline medium according to claim 1 , wherein the medium additionally comprises one or more compounds of the formula III,
in which
R 31 and R 32 each, independently of one another, denote a straight-chain alkyl, alkenyl, alkoxy, alkoxyalkyl or alkenyloxy radical having up to 12 C atoms,
denotes
and
Z 3 denotes a single bond, —CH 2 CH 2 —, —CH═CH—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —COO—, —OCO—, —C 2 F 4 —, —C 4 H 9 -, —C≡C— or —CF═CF—.
6. The liquid-crystalline medium according to claim 1 , wherein the medium additionally comprises one or more compounds of the formulae L-1 to L-11,
in which
R, R 1 and R 2 each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, where, in addition, one or more CH 2 groups in these radicals may be replaced by —O—, —S—,
—C≡C—, —CF 2 O—, —OCF 2 —, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another, a cyclopropyl ring, cyclobutyl ring or cyclopentyl ring,
alkyl denotes an alkyl radical having 1-6 C atoms, and
s denotes 1 or 2.
7. The liquid-crystalline medium according to claim 1 , wherein the medium additionally comprises one or more terphenyls of the formulae T-1 to T-22,
in which
R denotes a straight-chain alkyl or alkoxy radical having 1-7 C atoms,
m denotes 0, 1, 2, 3, 4, 5 or 6, and
n denotes 0, 1, 2, 3 or 4.
8. The liquid-crystalline medium according to claim 1 , wherein the medium additionally comprises one or more compounds of the formulae O—1 to O—17,
in which
R 1 and R 2 each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, where, in addition, one or more CH 2 groups in these radicals may be replaced by —O—, —S—,
—C≡C—, —CF 2 O—, —OCF 2 —, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another, a cyclopropyl ring, cyclobutyl ring or cyclopentyl ring.
9. The liquid-crystalline medium according to claim 1 , wherein the medium additionally comprises one or more compounds selected from the group of the compounds of the formulae BC, CR, PH-1, PH-2, BF-1, BF-2, BS-1 and BS-2,
in which
R B1 , R B2 , R CR1 , R CR2 , R 1 , R 2 each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, where, in addition, one or more CH 2 groups in these radicals may be replaced by —O—, —S—,
—C≡C—, —CF 2 O—, —OCF 2 —, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another, a cyclopropyl ring, cyclobutyl ring or cyclopentyl ring,
c denotes 0, 1 or 2
and d denotes 1 or 2.
10. The liquid-crystalline medium according to claim 1 , wherein the medium additionally comprises one or more compounds of the following formulae:
11. The liquid-crystalline medium according to claim 1 , characterised in that the medium comprises 5-60% of the compound of the following formula:
12. The liquid-crystalline medium according to claim 1 , wherein the medium additionally comprises one or more compounds selected from the group of the compounds of the formulae P-1 to P-5,
in which
R denotes straight-chain alkyl, alkoxy or alkenyl, each having 1 or 2 to 6 C atoms respectively, and
X denotes F, Cl, CF 3 , OCF 3 , OCHFCF 3 or CCF 2 CHFCF 3 .
13. The liquid-crystalline medium according to claim 1 , wherein the medium additionally comprises one or more compounds selected from the group of the compounds of the following formulae:
in which
R denotes a straight-chain alkyl or alkoxy radical having 1-7 C atoms,
m denotes 0, 1, 2, 3, 4, 5 or 6,
n denotes 0, 1, 2, 3 or 4,
R 1 , R 2 each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, where, in addition, one or more CH 2 groups in these radicals may be replaced by —O—, —S—,
—C≡C—, —CF 2 O—, —OCF 2 —, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another, a cyclopropyl ring, cyclobutyl ring or cyclopentyl ring,
c denotes 0, 1 or 2
d denotes 1 or 2,
R and R 10 each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, where, in addition, one or more CH 2 groups in these radicals may be replaced by —O—, —S—,
—C≡C—, —CF 2 O—, —OCF 2 —, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another, a cyclopropyl ring, cyclobutyl ring or cyclopentyl ring,
alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms,
alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms, and
x denotes 1 to 6.
14. The liquid-crystalline medium according to claim 1 , wherein the medium comprises the compound of the formula CC-4-V1 and the compound of the formula CC-3-V1:
15. The liquid-crystalline medium according to claim 1 , wherein the medium comprises at least one polymerisable compound.
16. The liquid-crystalline medium according to claim 1 , wherein the medium further comprises one or more additives.
17. The liquid-crystalline medium according to claim 16 , wherein the additive is a free-radical scavenger, antioxidant, dopant and/or UV stabiliser.
18. A process for the preparation of a liquid-crystalline medium according to claim 1 , comprising mixing at least one compound of the formulae IA to IH with at least one further compound wherein the further compound is a mesogenic compound, and optionally further mixing one or more additives and optionally further mixing at least one polymerisable compound.
19. An electro-optical display having active-matrix addressing, which comprises, as dielectric, a liquid-crystalline medium according to claim 1 .
20. The electro-optical display according to claim 19 , which is a VA, PSA, PA-VA, PS-VA, SA-VA, SS-VA, PALC, IPS, PS-IPS, FFS, UB-FFS or PS-FFS display.
21. The electro-optical display according to claim 20 , which is an IPS, PS-IPS, FFS or PS-FFS display which has a planar alignment layer.
22. The liquid-crystalline medium according to claim 1 , wherein the medium has a negative dielectric anisotropy, Δϑ, of less than −0.5.
23. The liquid-crystalline medium according to claim 1 , wherein the medium has a negative dielectric anisotropy, Δε, of −0.5 to −8.0.