Claims
- 1. A liquid-crystalline medium based on a mixture of polar compounds having positive dielectric anisotropy, comprising:
- one or more compounds of formula I ##STR82## in which X is fluorine, chlorine, OCF.sub.3 or OCHF.sub.2, ring A is trans-1,4-cyclohexylene or 1,4-phenylene, and R is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms; and
- one or more compounds selected from formula II ##STR83## one or more compounds selected from formula IV ##STR84## wherein R is as defined above,
- Q is --C.sub.2 H.sub.4 --, --C.sub.4 H.sub.8 -- or --CO--O,
- X' is F, Cl, CF.sub.3 or OCHF.sub.2,
- Y is H or F,
- A' is trans-1,4-cyclohexylene, and
- r is 0or 1.
- 2. A medium according to claim 1, further comprising one or more compounds selected from formulae V and VI: ##STR85## wherein R is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms; and
- Z is --C.sub.2 H.sub.4, --CO--O-- or --O--CO--.
- 3. A medium according to claim 1, further comprising one or more compounds selected from formulae VII to XII: ##STR86## wherein R is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms;
- X" is F, Cl, CF.sub.3, OCF.sub.3 or OCHF.sub.2 ;
- Y is H or F; and
- r is 0 or 1.
- 4. A medium according to claim 1, wherein the proportion of compounds of the formulae I, II, and IV together in the total mixture is at least 50% by weight.
- 5. A medium according to claim 1, wherein the proportion of compounds of the formula I in the total mixture is from 10-50% by weight.
- 6. A medium according to claim 1, wherein the proportion of compounds of formulae II and IV in the total mixture is 30-70% by weight.
- 7. In an electrooptical liquid-crystal display device containing a liquid-crystalline medium, the improvement wherein said medium is one of claim 1.
- 8. A medium according to claim 1, wherein X is chlorine, OCF.sub.3 or OCHF.sub.2.
- 9. A medium according to claim 1, further comprising one or more compounds of formula A ##STR87## in which R is alkyl, oxaalkyl, fluoroalkyl or alkenyl in each case having up to 7 carbon atoms,
- X" is F, Cl, CF.sub.3, OCF.sub.3 or OCHF.sub.2,
- Y is, in each case, H or F, and
- r is 0 or 1.
- 10. A medium according to claim 9, wherein the X and two Y substituents in said compound of formula A are selected from one of the following groups (a)-(d):
- ______________________________________ Y X" Y______________________________________(a) F F H,(b) H OCF.sub.3 H,(c) F OCF.sub.3 H, or(d) F OCHF.sub.2 H.______________________________________
- 11. A medium according to claim 9, wherein ring A is cyclohexylene and X is OCHF.sub.2 in formula I.
- 12. A medium according to claim 9, wherein the compound of formula A is of the formula ##STR88## wherein (F) is F or H and n is 1 to 7.
- 13. A medium according to claim 2, further comprising one or more compounds selected from formulae VII to XII: ##STR89## wherein R is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms,
- X" is F, Cl, CF.sub.3, OCF.sub.3 or OCHF.sub.2,
- Y is H or F, and
- r is 0 or 1.
- 14. In a method of generating an electrooptical liquid crystal display using an electrooptical liquid crystal display device, the improvement wherein said device is one of claim 7.
- 15. A medium according to claim 1, wherein Q is --C.sub.2 H.sub.4 -- or --C.sub.4 H.sub.8 --.
- 16. A medium according to claim 1, further comprising one or more compounds of the formula ##STR90## wherein R is alkyl, alkoxy, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms, and
- Y is H or F.
- 17. A medium according to claim 13, wherein said medium consists essentially of compounds selected from formulae I, II, and IV-XII.
- 18. A liquid-crystalline medium based on a mixture of polar compounds having positive dielectric anisotropy comprising:
- one or more compounds of formula I ##STR91## and one or more compounds of formula A ##STR92## in which R is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms,
- X is F, Cl, CF.sub.3, OCF.sub.3 or OCHF.sub.2,
- ring A is trans-1,4-cyclohexylene or 1,4-phenylene,
- Y is, in each case, H or F, and
- r is 0 or 1.
- 19. A medium according to claim 18, wherein the X and two Y substituents in said compound of formula A are selected from one of the following groups (a)-(d):
- ______________________________________ Y X Y______________________________________(a) F F H(b) H OCF.sub.3 H,(c) F OCF.sub.3 H, or(d) F OCHF.sub.2 H.______________________________________
- 20. A medium according to claim 18, wherein formula A is of the formula ##STR93## wherein (F) is F or H and n is 1 to 7.
- 21. A liquid-crystalline medium based on a mixture of polar compounds having positive dielectric anisotropy, comprising:
- one or more compounds of formula I ##STR94## in which X is fluorine, chlorine, CF.sub.3, OCF.sub.3 or OCHF.sub.2, ring A is trans-1,4-cyclohexylene or 1,4-phenylene, and R is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms, and
- one or more compounds selected from formulae V and VI: ##STR95## wherein R is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms, and
- Z is --C.sub.2 H.sub.4 --, --CO--O-- or --O--CO--.
- 22. A liquid-crystalline medium based on a mixture of polar compounds having positive dielectric anisotropy, comprising:
- one or more compounds of formula I ##STR96## in which X is fluorine, chlorine, CF.sub.3, OCF.sub.3 or OCHF.sub.2, ring A is trans-1,4-cyclohexylene or 1,4-phenylene, and R is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms; and
- one or more compounds selected from formulae II, III and IV ##STR97## wherein R is as defined above;
- Q is --C.sub.2 H.sub.4 --, --C.sub.4 H.sub.8 -- or --CO--O;
- X is as defined above;
- Y is H or F;
- ring A is as defined above; and
- r is 0 or 1;
- further comprising one or more compounds selected from formulae V and VI: ##STR98## wherein R is as defined above; and
- Z is --C.sub.2 H.sub.4, --CO--O-- or --O--CO--; and
- further comprising one or more compounds selected from formulae VII to XII: ##STR99## wherein R, X, Y and r are as defined above.
- 23. A medium according to claim 22, wherein said medium consists essentially of compounds selected from formulae I, II, and IV-XII.
Priority Claims (2)
| Number |
Date |
Country |
Kind |
| 40 24 760.0 |
Aug 1990 |
DEX |
|
| 41 07 119.0 |
Mar 1991 |
DEX |
|
Parent Case Info
This application is a continuation of application Ser. No. 07/781,151, filed Oct. 31, 1991, abandoned which is based on international application PCT/EP91/01337, filed Jul. 16, 1991 abandoned.
US Referenced Citations (6)
Foreign Referenced Citations (1)
| Number |
Date |
Country |
| 9001056 |
Feb 1990 |
WOX |
Continuations (1)
|
Number |
Date |
Country |
| Parent |
781151 |
Oct 1991 |
|
Patent Grant
5480581
