Liquid crystalline medium

Patent metadata

Field	Value
Publication number	US-9701903-B2
Application number	US-201514706463-A
Country	US
Kind code	B2
Filing date	May 7, 2015
Priority date	Jul 2, 2004
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

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.

First claim

The invention claimed is:

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 one compound of formula B-4

and
at least one compound of formula IB

and
at least one compound of formula II

and
optionally at least one compound of formula IA

in which
alkyl each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms;
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
at least one of the following compounds from groups A, B, or C:
A)
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;
B)
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;
C)
the following compound

wherein alkyl* denotes a straight-chain alkyl radical having 1-6 C atoms.

2. A liquid-crystalline medium according to claim 1 , which contains at least one compound of formula IA.

3. A liquid-crystalline medium according to claim 1 , which contains at least 10% of one or more compounds of formula IB and of formula II.

4. A liquid-crystalline medium according to claim 1 , which has a clearing point of 60-90° C.

5. A liquid-crystalline medium according to claim 1 , which has a Δ∈ value of −2.3 to −5.5.

6. 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.

7. 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.

8. 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

Assignees

• Merck Patent Gmbh

Inventors

• Klasen-Memmer Melanie
• Schoen Sabine

Classifications

• C09K19/3003

  Compounds containing at least two rings in which the different rings are directly linked (covalent bond) · CPC title

• C09K2019/122

  Ph-Ph · CPC title

• C09K19/44

  containing compounds with benzene rings directly linked · CPC title

• C09K2019/123

  Ph-Ph-Ph · CPC title

• C09K2019/3021

  Cy-Ph-Ph-Cy · CPC title