Liquid-crystal medium, and electro-optical display containing same

• US 6,969,542 B2
• Filed: 12/20/2001
• Issued: 11/29/2005
• Est. Priority Date: 12/20/2000
• Status: Active Grant

• Current Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Original Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Inventors: Weller, Clarissa, Klasen-Memmer, Melanie, Bremer, Matthias
• Primary Examiner(s): WU, SHEAN CHIU
• Application Number:
  US10/022,523
• Publication Number:
  US 20030017279A1
• Time in Patent Office: 1,440 Days
• Field of Search: 428/1.1, 252/299.61, 252/299.63, 252/299.66, 252/299.01
• US Class Current: 428/1.1
• CPC Class Codes: C09K 19/0216 Super Birefringence Effect (S.B.E.); Electrically Controlled Birefringence (E.C.B.)
• CPC Class Codes: C09K 19/20 linked by a chain containing carbon and oxygen atoms as chain links, e.g. esters or ethers
• CPC Class Codes: C09K 19/3001 Cyclohexane rings
• CPC Class Codes: C09K 19/3066 in which the rings are linked by a chain containing carbon and oxygen atoms, e.g. esters or ethers
• CPC Class Codes: C09K 19/3098 Unsaturated non-aromatic rings, e.g. cyclohexene rings
• 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 19/44 containing compounds with benzene rings directly linked
• CPC Class Codes: C09K 2019/3027 Compounds comprising 1,4-cyclohexylene and 2,3-difluoro-1,4-phenylene
• 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 nematic liquid-crystal media which comprise

• • a) a dielectrically negative, liquid-crystalline component A comprising one or more compounds of the formula I
    in which the parameters are as defined in the text, and
  • b) a dielectrically negative, liquid-crystalline component B, and optionally
  • c) a dielectrically neutral, liquid-crystalline component C, and optionally
  • d) a dielectrically positive, liquid-crystalline component D,
    and to the use of these media in liquid-crystal displays, and to liquid-crystal displays which use these media, in particular VAN and IPS displays.

Claims

1. A nematic liquid-crystal medium, which comprises

a) a dielectrically negative, liquid-crystalline component A which comprises one or more dielectrically negative compounds of one of the formulae I-1, I-3 and I-4:

in which

R¹¹ is alkyl having from 1 to 7 carbon atoms, alkoxy having from 1 to 7 carbon atoms or alkenyloxy having from 2 to 7 carbon atoms,

R¹² is alkyl or alkoxy having from 1 to 7 carbon atoms or alkenyl, alkenyloxy or alkoxyalkyl having from 2 to 7 carbon atoms, and

Z¹² is OCF₂ or CF₂O, and

b) a dielectrically negative, liquid-crystalline component, B, different from component A, and

c) optionally, a dielectrically neutral, liquid-crystalline component C, and

d) optionally, a dielectrically positive, liquid-crystalline component D.

2. A liquid-crystal medium of claim 1, wherein component B comprises one or more compounds selected from the group consisting of the compounds of the formulae II and III

in which

R²¹ is alkyl or alkoxy having from 1 to 7 carbon atoms or alkoxyalkyl, alkenyl or alkenyloxy having from 2 to 7 carbon atoms,

R²² is alkyl or alkoxy having from 1 to 7 carbon atoms or alkoxyalkyl, alkenyl or alkenyloxy having from 2 to 7 carbon atoms,

Z²¹ and Z²² are each, independently of one another, —

CH₂—

CH₂—

, —

CH═

CH—

, —

C≡

C—

, —

COO—

or a single bond,

 

and

 

are each, independently of one another,

L²¹ and L²² are both C—

F or one of the two is N and the other is C—

F,

m is 0 or 1,

Z³ is —

CH₂—

CH₂—

, —

CH═

CH—

, —

C≡

C—

, —

COO—

or a single bond,

R³¹ and R³² are each, independently of one another, alkyl or alkoxy having from 1 to 7 carbon atoms or alkoxyalkyl, alkenyl or alkenyloxy having from 2 to 7 carbon atoms, and

l is 1 or 2.

3. A liquid-crystal medium of claim 2, which comprises one or more compounds of the formula II.

4. A liquid-crystal medium of claim 2 which comprises one or more compounds of the formula III.

5. A liquid-crystal medium of claim 1, which comprises a component C.

6. A liquid-crystal medium of claim 1, which comprises a component D.

7. An electro-optical display comprising a liquid-crystal medium according to claim 1.

8. A display according to claim 7, which is an active matrix display.

9. A display according to claim 7 which is an ECB or IPS display.

10. The liquid-crystal medium of claim 1, wherein R¹¹ is alkyl, alkoxy, or alkenyloxy of 2 to 4 carbon atoms and Z¹² is OCF₂.

11. The liquid-crystal medium of claim 5, wherein component C comprises at least one compound of the formula IV:

in which

R⁴¹ and R⁴² are each independently of one another, alkyl or alkoxy having from 1 to 7 carbon atoms or alkoxyalkyl, alkenyl or alkenyloxy having from 2 to 7 carbon atoms,

Z¹, Z⁴², Z⁴³ independently of one another, —

CH₂CH₂—

, —

CH═

CH—

, —

COO—

or a single bond,

 

are each, independently of one another,

o and p, independently of one another, are 0 or 1.

12. The liquid-crystal medium of claim 1, which comprises 5% to 85% by weight of component A, 5% to 85% by weight of component B, 0 to 50% by weight of component C and 0 to 40% by weight of component D.

13. A display according to claim 8, which further comprises a thin film transistor or varistor.

14. A display according to claim 7, which further comprises a three-pole switching element.

15. A liquid-crystal medium of claim 6, wherein component D comprises at least one compound of the formula V:

wherein

R⁵ is alkyl or alkoxy having from 1 to 7 carbon atoms, or alkoxyalkyl, alkenyl or alkenyloxy having from 2 to 7 carbon atoms,

Z⁵¹, Z⁵² and Z⁵³ are each, independently of one another, —

CH₂—

CH₂—

, —

CH═

CH—

, —

C≡

C—

, —

COO—

or a single bond,

 

are each, independently of one another,

X⁵ is F, OCF₂H or OCF₃, and

Y⁵ is H or F, and

q and r are each, independently of one another, 0 or 1.

16. A liquid-crystal medium of claim 15, wherein Y⁵ is F and X⁵ is F or OCF₂H.

17. A liquid-crystal medium of claim 11, wherein at least two of the rings A⁴¹, A⁴², A⁴³ and A⁴⁴ are:

18. A liquid-crystal medium of claim 11, wherein at least two of the rings A⁴¹, A⁴², A⁴³ and A⁴⁴ are linked directly to one another.

19. A liquid-crystal medium of claim 11, wherein at least two of the rings A⁴¹, A⁴², A⁴³ and A⁴⁴ are linked directly to one another as:

20. A liquid-crystal medium of claim 1, which further comprises one or more dielectrically negative compounds of the formula VI:

in which

R⁶¹ and R⁶² are each independently alkyl having from 1 to 7 carbon atoms, alkoxy having from 1 to 7 carbon atoms, or alkenyloxy having from 2 to 7 carbon atoms,

Z⁶¹ is —

CH₂—

CH₂—

, —

CH═

CH—

, —

C≡

C—

, —

COO—

or a single bond,

L⁶¹ and L⁶² are both C—

F or one of the two is N and the other is C—

F, and

L⁶³ and L⁶⁴ are both C—

F or one of the two is N and the other is C—

F.

21. A liquid-crystal medium of claim 1, wherein, in formulae I-1, I-3 and I-4, Z¹² is OCF₂.