Liquid crystal medium

Abstract

The invention relates to a liquid-crystalline medium based on a mixture of polar compounds having positive dielectric anisotropy, characterised in that it comprises one or more compounds of the formula I in a total concentration of ≥40%, ##STR00001##
in which the parameters have the meanings indicated in claim 1, and to the use of the liquid-crystalline medium for electro-optical purposes, in particular in liquid-crystal light valves for lighting devices for motor vehicles, and to liquid-crystal light valves which comprise this medium and lighting devices for motor vehicles which contain such liquid-crystal light valves.

Claims

1. A liquid-crystalline medium comprising a mixture of polar compounds having positive dielectric anisotropy, comprising at least one compound of the formula I in a total concentration of ≥40%, ##STR00133## from 6% to 13% of at least one compound of formula IV-8 or IV-11 ##STR00134## and at least one compound of formula IB ##STR00135## in which R.sup.1 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where one or more H atoms in these radicals may be replaced by F and, in addition, one or more CH.sub.2 groups may each be replaced, independently of one another, by ##STR00136## —C≡C—, —CH═CH—, —O—, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another, ##STR00137## on each occurrence, identically or differently, denote ##STR00138## L.sup.11 and L.sup.12, independently of one another, denote H or F, X.sup.1 denotes F, Cl, CN, a halogenated alkyl radical, a halogenated alkenyl radical, a halogenated alkoxy radical or a halogenated alkenyloxy radical having up to 6 C atoms R.sup.41 and R.sup.42, independently of one another, denote n-alkyl having 1 to 7 C atoms, wherein the clearing temperature of said liquid-crystalline medium is at least 120° C.

2. The liquid-crystalline medium according to claim 1, comprising at least one compound of formulae I-1 to I-5, ##STR00139## in the parameters have the meanings indicated in claim 1 and L.sup.13 and L.sup.14, independently of one another, denote H or F.

3. The liquid-crystalline medium according to claim 1, additionally comprising at least one compound of the formula II ##STR00140## in which R.sup.2 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where one or more H atoms in these radicals may be replaced by F and, in addition, one or more CH.sub.2 groups may each be replaced, independently of one another, by ##STR00141## —C≡C—, —CH═CH—, —O—, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another, ##STR00142## on each occurrence, identically or differently, denote ##STR00143## L.sup.21 and L.sup.22, independently of one another, denote H or F, X.sup.2 denotes F, Cl, CN, a halogenated alkyl radical, a halogenated alkenyl radical, a halogenated alkoxy radical or a halogenated alkenyloxy radical having up to 6 C atoms, Z.sup.2 denotes —CH.sub.2CH.sub.2—, —CF.sub.2CF.sub.2—, —COO—, trans —CH═CH—, trans —CF═CF—, —CH.sub.2O— or a single bond.

4. The liquid-crystalline medium according to claim 3, wherein the at least one compound of the formula II are of the formulae II-1 to II-14, ##STR00144## ##STR00145## in which R.sup.2 denotes n-alkyl having up to 7 C atoms, L.sup.21 and L.sup.22, independently of one another, denote H or F and X.sup.2 denotes F, Cl, halogenated alkyl or halogenated alkoxy having up to 6 C atoms.

5. The liquid-crystalline medium according to claim 3, wherein the total concentration of the compounds of the formula II is 18% to 50%.

6. The liquid-crystalline medium according to claim 1, wherein said liquid-crystalline medium additionally comprises at least one compound of the formulae IA or IB-1, ##STR00146## wherein in formula IA R.sup.1, A.sup.11, A.sup.12, L.sup.11, L.sup.12 and X.sup.1 have the meanings indicated in claim 1 and L.sup.13 and L.sup.14 have the meaning indicated for L.sup.11 and in formula IB-1 at least one of L.sup.11 and L.sup.12 denotes F and one of L.sup.11 and L.sup.12 has the meaning indicated in claim 1 and X.sup.1 denotes F, Cl, CF.sub.3 or OCF.sub.3 and R.sup.1 has the meanings indicated in claim 1.

7. The liquid-crystalline medium according to claim 1, wherein said liquid-crystalline medium additionally comprises at least one compound of the formula III, ##STR00147## in which R.sup.3 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where one or more H atoms in these radicals may be replaced by F and, in addition, one or more CH.sub.2 groups may each be replaced, independently of one another, by ##STR00148## —CH═CH—, —O—, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another, ##STR00149## on each occurrence, independently of one another, denote ##STR00150## and Z.sup.3 on each occurrence, independently of one another, denotes —CH.sub.2CH.sub.2—, —COO—, trans —CH═CH—, trans —CF═CF—, —CH.sub.2O—, —C≡C—or a single bond, L.sup.31, L.sup.32 denote H or F, X.sup.3 denotes F, Cl, CN, a halogenated alkyl radical, a halogenated alkenyl radical, a halogenated alkoxy radical or a halogenated alkenyloxy radical having up to 6 C atoms.

8. The liquid-crystalline medium according to claim 7, wherein the at least one compound of the formula III is of the formulae III-1 to III-9, ##STR00151## in which R.sup.3, L.sup.31 and L.sup.32 have the meanings indicated in claim 7 and X.sup.3 denotes F, Cl, halogenated alkyl or halogenated alkoxy having to 6 C atoms.

9. A method which comprises including a liquid-crystalline medium according to claim 1 in an electro-optical component.

10. A method according to claim 9 wherein the electro-optical component is a liquid-crystal light valve for lighting devices for motor vehicles or a liquid-crystal display.

11. An electro-optical component comprising a liquid-crystalline medium according to claim 1.

12. The electro-optical component according to claim 11, where the component is a liquid-crystal light valve.

13. A lighting device for motor vehicles containing a liquid-crystal light valve according to claim 12.

14. A liquid-crystal display containing a liquid-crystal light valve according to claim 12.

15. The liquid crystalline medium of claim 1, wherein the clearing temperature of said liquid-crystalline medium is at least 130° C.

16. The liquid crystalline medium of claim 1, wherein the clearing temperature of said liquid-crystalline medium is at least 140° C.

17. The liquid crystalline medium of claim 1, wherein the medium retain the nematic phase down to −30° C. and the nematic phase range is at least 140 K.

18. The liquid crystalline medium of claim 1, wherein the medium retain an optical anisotropy (Δn) from 0.060 to 0.100, have a clearing point of at least 130° C. and the nematic phase range is at least 180 K.

19. The liquid crystalline medium of claim 1, wherein the medium has a TN threshold below 2.0 V.

20. The liquid crystalline medium of claim 3, wherein the tota concentration of compounds of the formula II in the medium is from 23% to 45%.

Description

EXAMPLE M1

(1) TABLE-US-00006 BCH-3F.F 7.00% Clearing point [° C.]: 122 BCH-5F.F 10.00% Δn [589 nm, 20° C.]: 0.0960 CCP-31 10.00% CCP-33 6.00% CCP-3F.F.F 10.00% CCP-5F.F.F 6.00% CBC-53F 6.00% CCQU-2-F 15.00% CCQU-3-F 15.00% CCQU-5-F 15.00%

EXAMPLE M2

(2) TABLE-US-00007 CCQU-2-F 15.00% Clearing point [° C.]: 140 CCQU-3-F 15.00% Δn [589 nm, 20° C.]: 0.0946 CCQU-5-F 15.00% Δε [1 kHz, 20° C.]: 13.8 CCP-3F.F.F 12.00% γ.sub.1 [mPa .Math. s, 20° C.]: 332 CCP-5F.F.F 6.00% CCGU-3-F 10.00% CCP-3-1 10.00% CBC-53F 6.00% CBC-33F 3.00% CDUQU-3-F 8.00%

EXAMPLE M3

(3) TABLE-US-00008 PGP-2-4 2.00% Clearing point [° C.]: 123 PGP-2-5 2.00% Δn [589 nm, 20° C.]: 0.0955 BCH-5F.F 7.00% CCP-3F.F.F 14.00% CCP-5F.F.F 5.00% CCQU-2-F 14.00% CCQU-3-F 16.00% CCQU-5-F 12.00% CCP-3-1 10.00% ECCP-5F.F 10.00% CBC-33F 4.00% CBC-53F 4.00%

EXAMPLE M4

(4) TABLE-US-00009 BCH-5F.F 12.00% Clearing point [° C.]: 140 BCH-3F.F.F 5.00% Δn [589 nm, 20° C.]: 0.0946 CCP-31 5.00% CCP-33 5.00% CCP-3F.F.F 15.00% CCP-5F.F.F 7.00% CBC-33F 4.00% CBC-53F 4.00% CCQU-2-F 8.00% CCQU-3-F 20.00% CCQU-5-F 15.00%

EXAMPLE M5

(5) TABLE-US-00010 BCH-5F.F 10.00% Clearing point [° C.]: 140 CCP-3F.F.F 14.00% Δn [589 nm, 20° C.]: 0.0946 CCP-5F.F.F 6.00% CCQU-2-F 14.00% CCQU-3-F 16.00% CCQU-5-F 12.00% CCGU-3-F 7.00% CCP-3-1 8.00% ECCP-5F.F 8.00% CBC-33F 2.00% CBC-53F 3.00%

EXAMPLE M6

(6) TABLE-US-00011 CCQU-2-F 8.00% Clearing point [° C.]: 140 CCQU-3-F 20.00% Δn [589 nm, 20° C.]: 0.0946 CCQU-5-F 18.00% CCP-3F.F.F 8.00% CCP-5F.F.F 4.00% CCGU-3-F 10.00% CCP-3-1 5.00% CCP-3-3 3.00% CCOC-3-3 3.00% CCOC-4-3 3.00% BCH-3F.F 8.00% BCH-5F.F 10.00%

EXAMPLE M7

(7) TABLE-US-00012 PGP-2-5 2.00% Clearing point [° C.]: 140 CCGU-3-F 8.00% Δn [589 nm, 20° C.]: 0.0946 BCH-3F.F 2.00% BCH-5F.F 6.00% CCP-3F.F.F 14.00% CCP-5F.F.F 6.00% CCQU-2-F 15.00% CCQU-3-F 18.00% CCQU-5-F 12.00% CCP-3-1 3.00% CCP-3-3 2.00% ECCP-5F.F 6.00% CBC-33F 3.00% CBC-53F 3.00%

EXAMPLE M8

(8) TABLE-US-00013 CCQU-2-F 15.00% Clearing point [° C.]: 131 CCQU-3-F 16.00% Δn [589 nm, 20° C.]: 0.0898 CCQU-5-F 14.00% Δε [1 kHz, 20° C.]: 12.7 CCP-1F.F.F 4.00% γ.sub.1 [mPa .Math. s, 20° C.]: 294 CCP-2F.F.F 7.00% CCP-3F.F.F 8.00% CCP-5F.F.F 5.00% CCGU-3-F 6.00% CCP-3-1 8.00% CBC-53F 7.00% CBC-33F 4.00% CDUQU-3-F 6.00%

EXAMPLE M9

(9) TABLE-US-00014 CCQU-2-F 14.00% Clearing point [° C.]: 130 CCQU-3-F 16.00% Δn [589 nm, 20° C.]: 0.0814 CCQU-5-F 15.00% Δε [1 kHz, 20° C.]: 11.0 CCP-2F.F.F  7.00% γ.sub.1 [mPa .Math. s, 20° C.]: 274 CCP-3F.F.F 14.00% CCP-5F.F.F  5.00% CCGU-3-F  8.00% CCP-3-1  8.00% CCOC-3-3  3.00% CCOC-4-3  4.00% CCCG-3-F  6.00%

EXAMPLE M10

(10) TABLE-US-00015 CCQU-2-F 14.00% Clearing point [° C.]: 127.9 CCQU-3-F 16.00% Δn [589 nm, 20° C.]: 0.0810 CCQU-5-F 15.00% Δε [1 kHz, 20° C.]: 11.5 CCP-2F.F.F  7.00% γ.sub.1 [mPa .Math. s, 20° C.]: 275 CCP-3F.F.F 14.00% CCP-5F.F.F  5.00% CCGU-3-F  8.00% CCP-3-1  8.00% CCOC-3-3  3.00% CCOC-4-3  4.00% CCCQU-3-F  6.00%

EXAMPLE M11

(11) TABLE-US-00016 CCQU-2-F 14.00% Clearing point [° C.]: 127.9 CCQU-3-F 16.00% Δn [589 nm, 20° C.]: 0.0810 CCQU-5-F 15.00% Δε [1 kHz, 20° C.]: 11.6 CCP-2F.F.F 7.00% γ.sub.1 [mPa .Math. s, 20° C.]: 285 CCP-3F.F.F 14.00% CCP-5F.F.F 5.00% CCGU-3-F 8.00% CCP-3-1 8.00% CCOC-3-3 3.00% CCOC-4-3 4.00% CCCQU-3-OT 6.00%

EXAMPLE M12

(12) TABLE-US-00017 CCQU-2-F 14.00% Clearing point [° C.]: 128.8 CCQU-3-F 16.00% Δn [589 nm, 20° C.]: 0.0796 CCQU-5-F 15.00% CCP-2F.F.F 7.00% CCP-3F.F.F 14.00% CCP-5F.F.F 5.00% CCGU-3-F 6.00% CCP-3-1 8.00% CCOC-3-3 3.00% CCOC-4-3 4.00% CCCQU-3-OT 4.00% CCCQU-3-F 4.00%