# US 9,428,694 B2 · Liquid crystal medium

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- Number: US 9,428,694 B2
- Document ID: US9428694B2
- Status: Granted
- Kind: B2
- Application number: 14/404,650
- Filed: 2013-05-21
- Published: 2015-05-28
- Granted: 2016-08-30
- Earliest claimed: 2012-06-02
- Assignees: Merck Patent GmbH
- Applicants: Merck Patent GmbH
- Inventors: Martin Engel; Melanie Klasen-Memmer; Christoph Marten; Stephan Derow
- Web page: https://patentgrep.com/patent/US9428694B2

## CPC

- C09K 19/56: Aligning agents
- C09K 19/12: at least two benzene rings directly linked, e.g. biphenyls
- C09K 19/3003: {Compounds containing at least two rings in which the different rings are directly linked (covalent bond)}
- G02F 1/1334: based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
- G02F 1/1341: Filling or closing of cells
- C09K 2019/0448: {the end chain group being a polymerizable end group, e.g. -Sp-P or acrylate}
- C09K 2019/122: {Ph-Ph}
- C09K 2019/3004: {Cy-Cy}
- C09K 2019/3009: {Cy-Ph}
- C09K 2019/301: {Cy-Cy-Ph}
- C09K 2019/3016: {Cy-Ph-Ph}
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS

## 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.

## Claims

### Claim 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
R1 and R2 each, independently of one another, denote alkyl having 1 to 12 C atoms, where one or two non-adjacent CH2 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,
L1-4 each, independently of one another, denote F, Cl, OCF3, CF3, CH3, CH2F or CHF2,
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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

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

### Claim 4 (depends on 1)

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%.

### Claim 5 (depends on 1)

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
R1 and R2 each, independently of one another, denote alkyl having 1 to 12 C atoms, where one or two non-adjacent CH2 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,
ZX denotes —CH═CH—, —CH2O—, —OCH2—, —CF2O—, —OCF2—, —O—,—CH2—, —CH2CH2— or a single bond, and
L1-4 each, independently of one another, denote F, Cl, OCF3, CF3, CH3, CH2F or CHF2.

### Claim 6 (depends on 1)

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
R3 and R4 each, independently of one another, denote alkyl having 1 to 12 C atoms, in which one or two non-adjacent CH2 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
Zy denotes —CH2CH2—, —CH═CH—, —CF2O—, —OCF2—, —CH2O—, —OCH2—, —COO—, —OCO—, —C2F4—, —CF═CF— or a single bond.

### Claim 7 (depends on 1)

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:
P1, P2 and P3 each, independently of one another, denote a polymerisable group,
Sp1, Sp2 and Sp3 each, independently of one another, denote a single bond or a spacer group,
where, optionally, one or more of the radicals P1-Sp1-, P1-Sp2- and P3-Sp3- is Raa, with the proviso that the compound has at least one of the radicals P1-Sp1-, P2-Sp2 and P3-Sp3- present which does not denote Raa,
Raa denotes H, F, Cl, CN or straight-chain or branched alkyl having 1 to 25 C atoms, in which one or more non-adjacent CH2 groups are optionally replaced, independently of one another, by C(R0)═C(R00)—, —C≡C—, —N(R0)—, —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 P1-Sp1-,
R0, R00 each, independently of one another and identically or differently on each occurrence, denote H or alkyl having 1 to 12 C atoms,
Ry and Rz each, independently of one another, denote H, F, CH3 or CF3,
X1, X2 and X3 each, independently of one another, denote —CO—O—, —O—CO— or a single bond,
Z1 denotes —O—, —CO—, —C(RyRz)— or —CF2CF2—,
Z2 and Z3 each, independently of one another, denote —CO—O—, —O—CO—, —CH2O—, —OCH2—, —CF2O—, —OCF2— or —(CH2)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.

### Claim 8 (depends on 1)

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%.

### Claim 9 (depends on 1)

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

### Claim 10 (depends on 1)

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.

### Claim 11 (depends on 10)

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.

### Claim 12 (depends on 10)

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 or two electrodes, and, located between the substrates, a layer of the LC medium comprising a polymerised component A and component B.

### Claim 13 (depends on 10)

A process for the production of an LC display according to claim 10, comprising the steps of filling the LC medium into 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 or two electrodes, and polymerising the polymerisable compounds of component A of the LC medium.

### Claim 14 (depends on 1)

A process for preparing an LC medium according to claim 1, comprising the steps of mixing one or more liquid crystalline compounds, at least one of which is a compound of formula I, with one or more polymerised or polymerisable compounds of component A and optionally with further liquid crystalline compounds and/or additives.

### Claim 15 (depends on 10)

An LC display according to claim 10, wherein the LC medium in the display has a pretilt angle resulting from in-situ polymerisation of the compound(s) of component A.

### Claim 16 (depends on 15)

An LC display according to claim 15, wherein the in-situ polymerisation is effected by application of an electric or magnetic field.

### Claim 17 (depends on 12)

The LC display according to claim 12, wherein the polymerised component A is obtained by polymerising component A by applying an electrical voltage to the electrodes.

### Claim 18 (depends on 13)

The process of claim 13, wherein the polymerising of the polymerisable compounds of component A is effected by applying an electrical voltage to the electrodes.

### Claim 19 (depends on 1)

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

### Claim 20 (depends on 1)

The LC medium according to claim 1, wherein the component A compounds are selected from polymerisable compounds which are reactive mesogens.

### Claim 21 (depends on 1)

The LC medium according to claim 1, wherein, in formula I, R1 and R2 are each, independently of one another, alkyl having 1 to 6 C atoms or alkyl having one or two non-adjacent CH2 groups replaced by —O— to provide alkoxy having 1 to 6 C atoms.

### Claim 22 (depends on 1)

The LC medium according to claim 1, wherein, in formula I, at least one of L1-4 is F.

### Claim 23 (depends on 2)

The LC medium according to claim 2, wherein, in formulae I-7 and I-8 alkenyl denotes CH2═CH—, CH2═CHCH2CH2—, CH3—CH═CH—, CH3—CH2—CH═CH—, CH3—(CH2)2—CH═CH—, CH3—(CH2)3—CH═CH— or CH3—CH═CH—(CH2)2—.

### Claim 24 (depends on 5)

The LC medium according to claim 5, wherein, in formula CY and PY, Zx is a single bond.

### Claim 25 (depends on 7)

The LC medium according to claim 7, wherein, in the formulae M1-M42:
Pl, P2 and P3 each, independently of one another, denote a polymerisable group, selected from an acrylate, methacrylate, fluoroacrylate, oxetane, vinyl, vinyloxy or epoxide group,
Sp1, Sp2 and Sp3 each, independently of one another, denote a single bond or a spacer group, selected from —(CH2)p1—, —(CH2)p1—O—, —(CH2)p1—CO—O— or —(CH2)p1—O—CO—O—, in which p1is an integer from 1 to 12, and where the linking to the adjacent ring in the last-mentioned groups takes place via the O atom,
where, optionally, one or more of the radicals P1-Sp1-, P1-Sp2- and P3-Sp3- is Raa, with the proviso that the compound has at least one of the radicals P1-Sp1-, P2-Sp2 and P3-Sp3- present which does not denote Raa, and
Raa denotes a-straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms, where the alkenyl and alkynyl radicals have at least two C atoms and the branched radicals have at least three C atoms.

### Claim 26 (depends on 7)

The LC medium according to claim 7, wherein, in the formulae M1-M42, L is F.