Liquid crystalline medium
The present invention relates to a liquid-crystalline medium based on a mixture of polar compounds having negative dielectric anisotropy (Δ∈), which is distinguished by the fact that it has a value for the ratio γ 1 /Δn 2 in the range 6-45 with a clearing point of >60° C. and a Δ∈ of ≦−2.3. Media of this type are particularly suitable for electro-optical displays having active-matrix addressing based on the ECB, PA LCD, FFS or IPS effect.
1. A liquid-crystalline medium based on a mixture of polar compounds having negative dielectric anisotropy (Δ∈), which has a value for the ratio γ 1 /Δn 2 in the range 6-45 Pa·s with a clearing point of >60° C. and a Δ∈ of ≦−2.3, and comprises
at least 10% by weight of at least one compound of formula B-4
in which
alkyl each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms;
and
at least two compounds of formulae IA, IB and/or II
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, in which one or more CH 2 groups are each, independently of one another, optionally replaced by —O—, —S—,
—C≡C—, —CF 2 O—, —CO—, —CO—O—, —O—CO— or —O—CO—O— in such a way that O atoms are not linked directly to one another, and
v denotes 1 to 6,
and wherein at least one of conditions A) or B) applies:
condition A):
the liquid-crystalline medium comprises one or more compounds of the following formulae To-1 and To-2
in which
R denotes 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, in which one or more CH 2 groups are optionally replaced by —O—, —S—,
—C≡—, —OCF 2 —, —CF 2 O—, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another, and alkyl denotes a straight-chain alkyl radical having 1-6 C atoms condition B):
the liquid-crystalline medium comprises one or more compounds of formulae N-1 to N-5
in which
R 1 and R 2 each, independently of one another, have the above-mentioned meanings and
Z, Z 1 and Z 2 each, independently of one another, denote —C 2 H 4 —, —CH═CH—, —(CH 2 ) 4 —, —(CH 2 ) 3 O—, —O(CH 2 ) 3 —, —CH═CHCH 2 CH 2 —, —CH 2 CH 2 CH═CH—, —CH 2 O—, —OCH 2 —, —COO—, —OCO—, —C 2 F 4 —, —CF═CF—, —CF═CH—, —CH═CF—, —CH 2 — or a single bond.
2. A liquid-crystalline medium according to claim 1 , which has a clearing point of 60-90° C.
3. A liquid-crystalline medium according to claim 1 , which has a Δ∈ value of −2.3 to −5.5.
4. A liquid-crystalline medium according to claim 1 , which having a clearing point of 70° C.±5° C. and a Δ∈ of −3.0±0.6 has the following rotational viscosities γ 1 at a defined Δn value:
Δn
γ 1
0.08 ± 0.005
≦125 mPa · s
0.09 ± 0.005
≦130 mPa · s
0.10 ± 0.005
≦135 mPa · s
0.11 ± 0.005
≦145 mPa · s
0.12 ± 0.005
≦150 mPa · s
0.13 ± 0.005
≦160 mPa · s
0.15 ± 0.01
≦170 mPa · s.
5. A liquid-crystalline medium according to claim 1 , which having a clearing point of 70° C.±5° C. and a Δ∈ of >−3.6 and ≦−4.4 has the following rotational viscosities γ 1 at a defined Δn value:
Δn
γ 1
0.08 ± 0.005
≦140 mPa · s
0.09 ± 0.005
≦165 mPa · s
0.10 ± 0.005
≦185 mPa · s
0.11 ± 0.005
≦190 mPa · s
0.12 ± 0.005
≦195 mPa · s
0.13 ± 0.005
≦205 mPa · s
0.15 ± 0.01
≦220 mPa · s.
6. A liquid-crystalline medium according to claim 1 , which having a clearing point of 70° C.±5° C. and a Δ∈ of >−4.4 and ≦−5.6 has the following rotational viscosities γ 1 at a defined Δn value:
Δn
γ 1
0.08 ± 0.005
≦185 mPa · s
0.09 ± 0.005
≦200 mPa · s
0.10 ± 0.005
≦210 mPa · s
0.11 ± 0.005
≦220 mPa · s
0.12 ± 0.005
≦230 mPa · s
0.13 ± 0.005
≦250 mPa · s
0.15 ± 0.01
≦270 mPa · s.
7. A liquid-crystalline medium according to claim 1 , which having a clearing point of 90° C.±5° C. and a Δ∈ of −3.0±0.6 has the following rotational viscosities γ 1 at a defined Δn value:
Δn
γ 1
0.08 ± 0.005
≦160 mPa · s
0.09 ± 0.005
≦170 mPa · s
0.10 ± 0.005
≦180 mPa · s
0.11 ± 0.005
≦190 mPa · s
0.12 ± 0.005
≦200 mPa · s
0.13 ± 0.005
≦210 mPa · s
0.15 ± 0.01
≦220 mPa · s.
8. A liquid-crystalline medium according to claim 1 , which having a clearing point of 90° C.±5° C. and a Δ∈ of >−3.6 and ≦−4.4 has the following rotational viscosities γ 1 at a defined Δn value:
Δn
γ 1
0.08 ± 0.005
≦185 mPa · s
0.09 ± 0.005
≦195 mPa · s
0.10 ± 0.005
≦215 mPa · s
0.11 ± 0.005
≦215 mPa · s
0.12 ± 0.005
≦215 mPa · s
0.13 ± 0.005
≦235 mPa · s
0.15 ± 0.01
≦250 mPa · s.
9. A liquid-crystalline medium according to claim 1 , which having a clearing point of 90° C.±5° C. and a Δ∈ of >−4.4 and ≦−5.6 has the following rotational viscosities γ 1 at a defined Δn value:
Δn
γ 1
0.08 ± 0.005
≦280 mPa · s
0.09 ± 0.005
≦275 mPa · s
0.10 ± 0.005
≦275 mPa · s
0.11 ± 0.005
≦275 mPa · s
0.12 ± 0.005
≦280 mPa · s.
10. A liquid-crystalline medium according to claim 1 , which has thresholds (capacitive) in the range 1.8-2.3 V.
11. A liquid-crystalline medium according to claim 1 , which comprises a compound of each of the compounds of the formulae IA, IB and II
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, in which one or more CH 2 groups are each, independently of one another, optionally replaced by —O—, —S—,
—C≡C—, —CF 2 O—, —CO—, —OC—O—, —O—CO— or —O—OC—O— in such a way that O atoms are not linked directly to one another, and
v denotes 1 to 6.
12. A liquid-crystalline medium according to claim 1 , which 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 alkenyl, alkyl, alkylalkoxy or alkoxy radical having up to 12 C atoms, and
Z denotes a single bond, —C 2 H 4 —, —CH═CH—, —(CH 2 ) 4 —, —(CH 2 ) 3 O—, —O(CH 2 ) 3 —, —CH═CHCH 2 CH 2 —, —CH 2 CH 2 CH═CH—, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —COO—, —OCO—, —C 2 F 4 —, —CHFCF 2 —, —CF═CF—, —CH═CF—, —CF═CH—, or —CH 2 —.
13. An electro-optical display having active-matrix addressing based on the ECB, PA LCD, FFS or the IPS effect, which contains, as dielectric, a liquid-crystalline medium according to claim 1 .
14. A liquid-crystalline medium according to claim 1 , which further comprises in total four compounds of formulae
15. A liquid-crystalline medium according to claim 1 , which further comprises at least one compound of formula IIIa and/or IIIb and at least one compound of formula IIIe
in which
alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, and
alkenyl denotes a straight-chain alkenyl radical having 2-6 C atoms.
16. A liquid-crystalline medium according to claim 12 , which comprises one or more compounds of formulae IIIa to IIIj:
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.
17. A liquid-crystalline medium according to claim 12 , which comprises one or more compounds of the following formulae
18. A liquid-crystalline medium according to claim 12 , which comprises at least three compounds of the following formulae
wherein alkyl denotes C n H 2n+1 , where n=3, 4 or 5.
19. A liquid-crystalline medium according to claim 1 , which comprises a compound of formulae IA and/or IB
in which
R 1 is a straight-chain alkenyl or alkyl, and
v denotes 1 to 6.
20. A liquid-crystalline medium according to claim 19 , wherein when R 1 denotes alkenyl, said group is CH 2 ═CH, CH 3 —CH═CH, C 3 H 7 —CH═CH, CH 2 ═CH—C 2 H 4 or CH 3 —CH═CH—C 2 H 4 .
21. A liquid-crystalline medium according to claim 11 , which comprises
10-40% by weight of one or more compounds of the formulae IA and IB, and
10-40% by weight of one or more compounds of the formula II.
22. A liquid-crystalline medium according to claim 1 , which further comprises one or more compounds of the following formulae, which compounds when present are each in an amount of at least 5% by weight
in which
R 13 -R 27 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, in which one or more CH 2 groups are optionally replaced by —O—, —S—,
—C≡C—, —OCF 2 —, —CF 2 O—, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another,
z and m each, independently of one another, denote 1-6,
R E denotes H, CH 3 , C 2 H 5 or n-C 3 H 7 , and
x denotes 0, 1, 2 or 3.
23. A liquid-crystalline medium according to claim 1 , which further comprises one or more compounds of the following formulae T-1 to T-22
in which
R denotes 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, in which one or more CH 2 groups are optionally replaced by —O—, —S—,
—C≡C—, —OCF 2 —, —CF 2 O—, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another.
24. A liquid-crystalline medium according to claim 1 , which further comprises one or more compounds of the following formulae B-1 to B-2
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.
25. A liquid-crystalline medium according to claim 24 , which comprises one or more compounds of the following formulae
26. A liquid-crystalline medium according to claim 1 , wherein condition A) applies, wherein the liquid-crystalline medium comprises one or more compounds of the following formulae To-1 and To-2
in which
R denotes 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, in which one or more CH 2 groups are optionally replaced by —O—, —S—,
—C≡C—, —OCF 2 —, —CF 2 O—, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another, and alkyl denotes a straight-chain alkyl radical having 1-6 C atoms.
27. A liquid-crystalline medium according to claim 1 , which further comprises one or more compounds of the following formula
alkyl* denotes a straight-chain alkyl radical having 1-6 C atoms.
28. A liquid-crystalline medium according to claim 1 , which further comprises at least one compound of the formulae
29. A liquid-crystalline medium according to claim 1 , wherein condition B) applies, wherein the liquid-crystalline medium comprises one or more compounds of formulae N-1 to N-5
in which
R 1 and R 2 each, independently of one another, denote straight-chain alkyl, straight-chain alkoxy or straight-chain alkenyl, and
Z, Z 1 and Z 2 each, independently of one another, denote —C 2 H 4 —, —CH═CH—, —(CH 2 ) 4 —, —(CH 2 ) 3 O—, —O(CH 2 ) 3 —, —CH═CHCH 2 CH 2 —, —CH 2 CH 2 CH═CH—, —CH 2 O—, —OCH 2 —, —COO—, —OCO—, —C 2 F 4 —, —CF═CF—, —CF═CH—, —CH═CF—, —CH 2 — or a single bond.
30. A liquid-crystalline medium according to claim 1 , which further comprises one or more compounds of the following formulae
wherein n=1-12.
31. A liquid-crystalline medium according to claim 1 , which further comprises the following compound
wherein alkyl* denotes a straight-chain alkyl radical having 1-6 C atoms.