# US 5,350,535 A · Liquid-crystalline medium

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- Number: US 5,350,535 A
- Document ID: US5350535A
- Status: Granted
- Kind: A
- Application number: 07/688,522
- Filed: 1991-06-10
- Granted: 1994-09-27
- Earliest claimed: 1990-04-13
- Assignees: Merck Patent GmbH
- Inventors: Bernhard Rieger; Reinhard Hittich; Volker Reiffenrath; Herbert Plach
- Web page: https://patentgrep.com/patent/US5350535A

## CPC

- C09K 19/3001: {Cyclohexane rings}
- C09K 19/3003: {Compounds containing at least two rings in which the different rings are directly linked (covalent bond)}
- C09K 19/44: containing compounds with benzene rings directly linked
- C09K 2019/3021: {Cy-Ph-Ph-Cy}
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE

## Abstract

The invention relates to a liquid-crystalline medium based on a mixture of polar compounds of positive dielectric anisotropy, characterized in that it contains one or more compounds of the general formula I ##STR1## in which X is fluorine, chlorine, CF.sub.3, OCF.sub.3 or OCHF.sub.2, and R is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms.

## Claims

### Claim 1

A liquid-crystalline medium based on a mixture of polar compounds having positive dielectric anisotropy, comprising one or more compounds of the formula I ##STR71## in which X is fluorine, chlorine, CF.sub.3, OCF.sub.3 or OCHF.sub.2, and R is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having 1 to 7 carbon atoms, and one or more compounds of the formulae II-IV ##STR72## in which the individual radical R is independently as defined above,
X" is fluorine, chlorine, CF.sub.3 or OCF.sub.3,
Y.sup.1 ' and Y.sup.2 ' are in each case F, and
r is 0 to 1.

### Claim 2 (depends on 1)

A medium according to claim 1, further comprising more compounds selected from the group consisting of the formulae IX to XII: ##STR73## in which R and X are each, independently of one another, as defined in claim 1, and Y.sup.1 and Y.sup.2 are in each case H or F.

### Claim 3 (depends on 1)

Medium according to claim 1, wherein the proportion of compounds of the formulae I to IV together is at least 50% by weight in the total mixture.

### Claim 4 (depends on 1)

Medium according to claim 1, wherein the proportion of compounds of the formula I is from 10 to 50% by weight in the total mixture.

### Claim 5 (depends on 1)

Medium according to claim 1, wherein the proportion of compounds of the formulae II to IV is from 30 to 70% by weight in the total mixture.

### Claim 6 (depends on 1)

Electrooptical liquid-crystal display containing a liquid-crystalline medium according to claim 1.

### Claim 7 (depends on 2)

A medium according to claim 2 further comprising one or more compounds selected from the group consisting of formulae V to VIII: ##STR74## in which R and X are each independently as defined in claim 2, Y.sup.1' and Y.sup.2' are in each case F, r is 0 or 1, and which consists essentially of compounds selected from the group consisting of formulae I to XII.

### Claim 8

A liquid-crystalline medium based on a mixture of polar compounds having positive dielectric anisotropy, comprising one or more compounds of the formula ##STR75## in which X' is fluorine or chlorine and R is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having 1 to 7 carbon atoms, one or more compounds selected from the group consisting of the formulae II, III and IV: ##STR76## in which the individual radicals R and X' are independently as defined above.
Y.sup.1 and Y.sup.2 are in each case H or F, and
r is 0 to 1, and
one or more compounds selected from the group consisting of the formulae IX to XII: ##STR77## in which the individual radicals R, Y.sup.1, Y.sup.2 and r are independently as defined above, and
X is F, Cl, CF.sub.3, OCF.sub.3 or OCHF.sub.2.

### Claim 9 (depends on 8)

A medium according to claim 8, wherein the proportion of compounds of the formulae I to IV together is at least 50% by weight in the total mixture.

### Claim 10 (depends on 8)

A medium according to claim 8, wherein the proportion of compounds of formula I is from 10 to 50% by weight in the total mixture.

### Claim 11 (depends on 8)

A medium according to claim 8, wherein the proportion of compounds of formula II to IV is from 30 to 70% by weight in the total mixture.

### Claim 12 (depends on 8)

A medium according to claim 8 further comprising one or more compounds selected from the group consisting of formulae V to VIII: ##STR78## in which R and X are each independently as defined in claim 8, Y.sup.1' and Y.sup.2' are each case F, r is 0 or 1, and which consists essentially of compounds selected from the group consisting of formulae I to XII.

### Claim 13 (depends on 8)

An electrooptical liquid-crystal display containing a liquid-crystalline medium according to claim 8.

### Claim 14

A liquid-crystalline medium based on a mixture of polar compounds having positive dielectric anisotropy, comprising one or more compounds of the formula I ##STR79## in which X is fluorine, chlorine, CF.sub.3, OCF.sub.3 or OCHF.sub.2, and R is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having 1 to 7 carbon atoms and one or more compounds selected from the group consisting of the formulae V to VIII: ##STR80## in which R is independently as defined above,
X" is fluorine, chlorine, CF.sub.3 or OCF.sub.3,
Y.sup.1' and Y.sup.2' are in each case F, and
r is 0 or 1.

### Claim 15 (depends on 14)

An electrooptical liquid-crystal display containing a liquid-crystalline medium according to claim 14.