Liquid crystal medium

Patent metadata

Field	Value
Publication number	US-9428694-B2
Application number	US-201314404650-A
Country	US
Kind code	B2
Filing date	May 21, 2013
Priority date	Jun 2, 2012
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

The present invention relates to a liquid crystal (LC) medium, to its use for optical, electro-optical and electronic purposes, in particular in LC displays, especially in LC displays of the PS (“polymer sustained”) or PSA (“polymer sustained alignment”) type, and to LC displays, especially PS or PSA displays, comprising said LC medium.

First claim

The invention claimed is:

1. An LC medium comprising
a polymerised or polymerisable component A comprising one or more polymerised or polymerisable compounds, and
a liquid crystalline component B, comprising one or more, monomeric and unpolymerisable compounds selected from mesogenic or liquid crystal compounds,
wherein component B comprises one or more compounds of formula I

wherein

denotes

R 1 and R 2 each, independently of one another, denote alkyl having 1 to 12 C atoms, where one or two non-adjacent CH 2 groups are optionally replaced by —O—, —CH═CH—, —CO—, —OCO— or —COO— in such a way that O atoms are not linked directly to one another,
L 1-4 each, independently of one another, denote F, Cl, OCF 3 , CF 3 , CH 3 , CH 2 F or CHF 2 ,
and component B optionally comprises one or more other monomeric and unpolymerisable compounds,
provided that the LC medium does not contain a terphenyl compound wherein one or more phenyl rings are fluorinated in 2- and/or 3 position.

2. The LC medium according to claim 1 , wherein the compounds of formula I are selected from the group consisting of compounds of the following sub-formulae:

wherein alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, alkenyl denotes a straight-chain alkenyl radical having 2-6 C atoms, and (O) denotes an oxygen atom or a single bond.

3. The LC medium according to claim 1 , which comprises 2, 3, 4 or 5, distinct compounds of formula I.

4. The LC medium according to claim 1 , wherein the proportion of compounds of formula I in the mixture as a whole is from 1 to 45%, and the content of an individual compound of formula I is in each case from 1 to 20%.

5. The LC medium according to claim 1 , wherein component B further comprises one or more compounds of the formulae CY and/or PY:

in which the individual radicals have the following meanings:
a denotes 1 or 2,

denotes

R 1 and R 2 each, independently of one another, denote alkyl having 1 to 12 C atoms, where one or two non-adjacent CH 2 groups are optionally 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 denotes —CH═CH—, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —O—,—CH 2 —, —CH 2 CH 2 — or a single bond, and
L 1-4 each, independently of one another, denote F, Cl, OCF 3 , CF 3 , CH 3 , CH 2 F or CHF 2 .

6. The LC medium according to claim 1 , wherein component B further comprises one or more compounds of the following formula:

in which the individual radicals have the following meanings:

denotes

denotes

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 are optionally 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
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.

7. The LC medium according to claim 1 , wherein component A comprises one or more compounds selected from the following formulae

in which the individual radicals have the following meanings:
P 1 , P 2 and P 3 each, independently of one another, denote a polymerisable group,
Sp 1 , Sp 2 and Sp 3 each, independently of one another, denote a single bond or a spacer group,
where, optionally, one or more of the radicals P 1 -Sp 1 -, P 1 -Sp 2 - and P 3 -Sp 3 - is R aa , with the proviso that the compound has at least one of the radicals P 1 -Sp 1 -, P 2 -Sp 2 and P 3 -Sp 3 - present which does not denote R aa ,
R aa denotes H, F, Cl, CN or straight-chain or branched alkyl having 1 to 25 C atoms, in which one or more non-adjacent CH 2 groups are optionally replaced, independently of one another, by C(R 0 )═C(R 00 )—, —C≡C—, —N(R 0 )—, —O—, —S—, —CO—, —CO—O—, —O—CO— or —O—CO—O— in such a way that O and/or S atoms are not linked directly to one another, and in which one or more H atoms are optionally replaced by F, Cl, CN or P 1 -Sp 1 -,
R 0 , R 00 each, independently of one another and identically or differently on each occurrence, denote H or alkyl having 1 to 12 C atoms,
R y and R z each, independently of one another, denote H, F, CH 3 or CF 3 ,
X 1 , X 2 and X 3 each, independently of one another, denote —CO—O—, —O—CO— or a single bond,
Z 1 denotes —O—, —CO—, —C(R y R z )— or —CF 2 CF 2 —,
Z 2 and Z 3 each, independently of one another, denote —CO—O—, —O—CO—, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 — or —(CH 2 ) n —, where n is 2, 3 or 4,
L on each occurrence, identically or differently, denotes F, Cl, CN or straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms,
L′ and L″ each, independently of one another, denote H, F or Cl,
r denotes 0, 1, 2, 3 or 4,
s denotes 0, 1, 2 or 3,
t denotes 0, 1 or 2, and
x denotes 0 or 1.

8. The LC medium according to claim 1 , wherein the proportion of polymerised or polymerisable compounds of component A in the mixture as a whole is from 0.05 to 5%.

9. The LC medium according to claim 1 , wherein the compounds of component A are polymerised.

10. An LC display which is a polymer stabilised, PS, display or a polymer sustained alignment, PSA, display, comprising an LC medium according to claim 1 .

11. The LC display according to claim 10 , which is a PSA-VA, PSA-OCB, PSA-IPS, PS-FFS, PSA-posi-VA or PSA-TN display.

12. The LC display according to claim 10 , which contains an LC cell having two substrates and two electrodes, where at least one substrate is transparent to light and at least one substrate has one o

Assignees

• Merck Patent Gmbh

Inventors

• Engel Martin
• Klasen-Memmer Melanie
• Marten Christoph
• Derow Stephan

Classifications

• C09K19/12 Primary

  at least two benzene rings directly linked, e.g. biphenyls · CPC title

• C09K19/3003

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

• C09K2019/3016

  Cy-Ph-Ph · CPC title

• C09K2019/0448

  the end chain group being a polymerizable end group, e.g. -Sp-P or acrylate · CPC title

• C09K2019/122

  Ph-Ph · CPC title