Liquid-crystalline medium and liquid-crystal display

• US 8,585,925 B2
• Filed: 02/03/2010
• Issued: 11/19/2013
• Est. Priority Date: 02/06/2009
• Status: Active Grant

• Current Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Original Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Inventors: Czanta, Markus, Saito, Izumi, Schoenefeld, Christian, Lee, Seung-Eun, Lee, Sang-Kyu, Bae, Ji-Hong
• Primary Examiner(s): Visconti, Geraldina
• Application Number:
  US13/148,131
• Publication Number:
  US 20120032112A1
• Time in Patent Office: 1,385 Days
• Field of Search: 252/299.01, 252/299.6, 252/299.63, 252/299.64, 252/299.66, 428/1.1, 349/86, 349/182
• US Class Current: 252/299.63
• CPC Class Codes: C09K 19/42 Mixtures of liquid crystal compounds covered by two or more of the preceding groups C09K19/06 - C09K19/40
• CPC Class Codes: C09K 2019/0448 the end chain group being a polymerizable end group, e.g. -Sp-P or acrylate
• CPC Class Codes: C09K 2019/0466 the linking chain being a -CF2O- chain
• CPC Class Codes: C09K 2019/548 stabilizing the alignment; Polymer stabilized alignment
• CPC Class Codes: C09K 2323/00 Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition

Abstract

The present invention relates to dielectrically positive, preferably nematic, media comprising one or more polymerisable compounds, to polymer-stabilized media obtained therefrom, to the use thereof in liquid-crystal displays, and to these displays, in particular PSA-IPS, PSA-FFS and PSA-positive VA displays.

Claims

1. A liquid-crystalline medium having positive dielectric anisotropy, comprising

one or more polymerizable compounds,

one or more dielectrically positive compounds of formula II:

2. A medium according to claim 1, wherein the concentration of the polymerizable compounds in the medium is from 0.05% to 10%.

3. A medium according to claim 1, wherein the one or more polymerizable compounds comprise one or more compounds of formula I

R^a-A¹-(Z¹-A²)_m1-R^b 

 

I

in which

R^a and R^b each, independently of one another, denotes P, P-Sp-, H, halogen, SF₅, NO₂, an alkyl, alkenyl or alkynyl group,

P on each appearance, independently of one another, denotes a polymerizable group,

Sp on each appearance, independently of one another, denotes a spacer group or a single bond,

A¹ and A² each, independently of one another and also A² independently of one another on each appearance, denotes an aromatic, heteroaromatic, alicyclic or heterocyclic group, which is optionally mono- or polysubstituted by L,

Z¹ on each appearance, independently of one another, denotes —

O—

, —

S—

, —

CO—

, —

CO—

O—

, —

OCO—

, —

O—

CO—

O—

, —

OCH₂—

, —

CH₂O—

, —

SCH₂—

, —

CH₂S—

, —

CF₂O—

, —

OCF₂—

, —

CF₂S—

, —

SCF₂—

, —

(CH₂)_n1—

, —

CF₂CH₂—

, —

CH₂CF₂—

, —

(CF₂)_n1—

, —

CH═

CH—

, —

CF═

CF—

, —

C≡

C—

, —

CH═

CH—

COO—

, —

OCO—

CH═

CH—

, CR⁰R⁰⁰ or a single bond,

L denotes P, P-Sp-, OH, CH₂OH, F, Cl, Br, I, —

CN, —

NO₂, —

NCO, —

NCS, —

OCN, —

SCN, —

C(═

O)N(R^x)₂, —

C(═

O)Y¹, —

C(═

O)R^x, —

N(R^x)₂, optionally substituted silyl, optionally substituted aryl having 6 to 20 C atoms, or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, in which one or more H atoms are optionally replaced by F, Cl, P or P-Sp-,

R⁰ and R⁰⁰ each, independently of one another, denotes H or alkyl having 1 to 12 C atoms,

R^x denotes P, P-Sp-, H, halogen, straight-chain, branched or cyclic alkyl having 1 to 25 C atoms, in which one or more non-adjacent CH₂ groups are optionally replaced by —

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, P or P-Sp-, an optionally substituted aryl or aryloxy group having 6 to 40 C atoms, or an optionally substituted heteroaryl or heteroaryloxy group having 2 to 40 C atoms,

m1 denotes 0, 1, 2, 3 or 4, and

n1 denotes 0, 1, 2, 3 or 4,

where at least one substituent from the group R^a, R^b and L present denotes a group P or P-Sp- or contains at least one such group.

4. A medium according to claim 1, which comprises one or more compounds of formula II.

5. A medium according to claim 1, which comprises one or more compounds of formula III.

6. A medium according to claim 1, which comprises one or more compounds of formula II and one or more compounds of formula III.

7. A medium according to claim 1, which further comprises one or more dielectrically neutral compounds of formula VI

8. A liquid-crystal display, which contains a medium according to claim 1.

9. A display, which contains a medium according to claim 1 which has been stabilized by polymerization of the one or more polymerizable compounds.

10. A display according to claim 8, which is addressed by an active matrix.

11. A display according to claim 8, which is a PS-IPS or PS-FFS display.

12. A display according to claim 8, which is a PS positive VA display.

13. A process for the production of a liquid-crystal display, comprising stabilizing a medium according to claim 1 in the display by polymerization of the one or more polymerizable compounds.

14. A process according to claim 13, wherein no electrical voltage is applied during the polymerization of the one or more polymerizable compounds.

15. A medium according to claim 1, further comprising one or more dielectrically neutral compounds of formula IV

16. A medium according to claim 3, wherein in formula I at least one of R^a and R^b denotes P-Sp-.

17. A liquid-crystalline medium having positive dielectric anisotropy, comprising

one or more polymerizable compounds at a concentration of ≧

0.01% to ≦

5%,

one or more dielectrically positive compounds of formula II;

18. A medium according to claim 17, which comprises one or more polymerizable compounds at a concentration of ≧

0.1% to ≦

3%.

19. A medium according to claim 17, wherein the one or more polymerizable compounds comprise one or more compounds of formula I

R^a-A¹-(Z¹-A²)_m1-R^b 

 

I

in which

R^a and R^b each, independently of one another, denotes P, P-Sp-, H, halogen, SF_S, NO₂, an alkyl, alkenyl or alkynyl group,

P on each appearance, independently of one another, denotes a polymerizable group,

Sp on each appearance, independently of one another, denotes a spacer group or a single bond,

A¹ and A² each, independently of one another and also A² independently of one another on each appearance, denotes an aromatic, heteroaromatic, alicyclic or heterocyclic group, which is optionally mono- or polysubstituted by L,

Z¹ on each appearance, independently of one another, denotes —

O—

, —

S—

, —

CO—

, —

CO—

O—

, —

OCO—

, —

O—

CO—

O—

, —

OCH₂—

, —

CH₂O—

, —

SCH₂—

, —

CH₂S—

, —

CF₂O—

, —

OCF₂—

, —

CF₂S—

, —

SCF₂—

, —

(CH₂)_n1—

, —

CF₂CH₂—

, —

CH₂CF₂—

, —

(CF₂)_n1—

, —

CH═

CH—

, —

CF═

CF—

, —

C≡

C—

, —

CH═

CH—

COO—

, —

OCO—

CH═

CH—

, CR⁰R⁰⁰ or a single bond,

L denotes P, P-Sp-, OH, CH₂OH, F, Cl, Br, I, —

CN, —

NO₂, —

NCO, —

NCS, —

OCN, —

SCN, —

C(═

O)N(R^x)₂, —

C(═

O)Y¹, —

C(═

O)R^x, —

N(R^x)₂, optionally substituted silyl, optionally substituted aryl having 6 to 20 C atoms, or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, in which one or more H atoms are optionally replaced by F, Cl, P or P-Sp-,

R⁰ and R⁰⁰ each, independently of one another, denotes H or alkyl having 1 to 12 C atoms,

R^x denotes P, P-Sp-, H, halogen, straight-chain, branched or cyclic alkyl having 1 to 25 C atoms, in which one or more non-adjacent CH₂ groups are optionally replaced by —

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, P or P-Sp-, an optionally substituted aryl or aryloxy group having 6 to 40 C atoms, or an optionally substituted heteroaryl or heteroaryloxy group having 2 to 40 C atoms,

m1 denotes 0, 1, 2, 3 or 4, and

n1 denotes 0, 1, 2, 3 or 4,

where at least one substituent from the group R^a, R^b and L present denotes a group P or P-Sp- or contains at least one such group.