LIQUID CRYSTAL MEDIUM

Abstract

Liquid-crystalline (LC) media having positive dielectric anisotropy and liquid-crystal displays (LCDs) containing these media, especially displays addressed by an active matrix and in particular LC displays of the TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, XB-FFS, PS-FFS, SA-HB-FFS, SA-XB-FFS, polymer stabilised SA-HB-FFS, polymer stabilised SA-XB-FFS, positive VA or positive PS-VA type.

Claims

1. A liquid crystal medium comprising a) one or more compounds of formula I ##STR00601## in which R.sup.11 and R.sup.12 identically or differently, denote H, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl, alkenyloxy each having 3 to 15 C atoms, where one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by ##STR00602## CHCH, CC, CF.sub.2O, OCF.sub.2, O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, L.sup.11 and L.sup.12 independently denote H, F, Cl, CH.sub.3, CF.sub.3 or CHF.sub.2; and b) one or more compounds selected from the group of compounds of formulae II and/or III ##STR00603## in which R.sup.2 and R.sup.3, independently of one another, denote a straight-chain or branched alkyl or alkoxy radical that is unsubstituted or halogenated and has 1 to 15 C atoms, where one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by ##STR00604## CC, CF.sub.2O, CHCH, O, COO or OCO in such a way that O atoms are not linked directly to one another, ##STR00605## independently of one another denote ##STR00606## L.sup.21, L.sup.22, L.sup.31 and L.sup.32 independently of each other, denote H or F, Y.sup.2 and Y.sup.3 identically or differently, denote H or CH.sub.3, X.sup.2 and X.sup.3 independently of each other, denote halogen, halogenated alkyl or halogenated alkoxy with 1 to 3 C-atoms or halogenated alkenyl or halogenated alkenyloxy with 2 or 3 C-atoms, Z.sup.3 denotes CH.sub.2CH.sub.2, CF.sub.2CF.sub.2, COO, trans- CHCH, trans-CFCF, CH.sub.2O or a single bond, and l, m, n and o are, independently of each other, 0 or 1.

2. The medium according to claim 1, wherein L.sup.11 and L.sup.12 independently denote H or F.

3. The liquid crystal medium according to claim 1, wherein the one or more compounds of formula II are selected from the compounds of formulae II-1, II-2 and/or II-3 ##STR00607## in which L.sup.23 and L.sup.24 denote H or F, R.sup.2 independently of one another, denote a straight-chain or branched alkyl or alkoxy radical that is unsubstituted or halogenated and has 1 to 15 C atoms, where one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by ##STR00608## CC, CF.sub.2O, CHCH, O, COO or OCO in such a way that O atoms are not linked directly to one another, ##STR00609## and independently of one another denote ##STR00610## L.sup.21 and L.sup.22, independently of each other, denote H or F, and X.sup.2 independently of each other, denote halogen, halogenated alkyl or halogenated alkoxy with 1 to 3 C-atoms or halogenated alkenyl or halogenated alkenyloxy with 2 or 3 C-atoms.

4. The liquid crystal medium according to one claim 1, wherein the one or more compounds of formula III are selected from compounds of formulae III-1 and/or III-2 ##STR00611## in which R.sup.3, independently of one another, denote a straight-chain or branched alkyl or alkoxy radical that is unsubstituted or halogenated and has 1 to 15 C atoms, where one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by ##STR00612## CC, CF.sub.2O, CHCH, O, COO or OCO in such a way that O atoms are not linked directly to one another, ##STR00613## independently of one another ##STR00614## L.sup.31 and L.sup.32 independently of each other, denote H or F, X.sup.3 independently of each other, denote halogen, halogenated alkyl or halogenated alkoxy with 1 to 3 C-atoms or halogenated alkenyl or halogenated alkenyloxy with 2 or 3 C-atoms, and n and o are, independently of each other, 0 or 1.

5. The liquid crystal medium according to claim 1, wherein the medium further comprises one or more compounds selected from the group consisting of the compounds of formulae Y, B, BC, CR, PH-1 and/or PH-2: ##STR00615## in which R.sup.Y1, R.sup.Y2, R.sup.B1, R.sup.B2, R.sup.CR1, R.sup.CR2, R.sub.P1, and R.sub.P2 each, independently of one another, denote H, an alkyl or alkoxy radical having 1 to 15 C atoms, where one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by ##STR00616## CHCH, CC, CF.sub.2O, OCF.sub.2, O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, ##STR00617## on each occurrence, independently of one another, denote a) 1,4-cyclohexenylene or 1,4-cyclohexylene radical, in which one or two non-adjacent CH.sub.2 groups may be replaced by O or S, b) a 1,4-phenylene radical, in which one or two CH groups may be replaced by N, or c) a radical from the group spiro[3.3]heptane-2,6-diyl, 1,4-bicyclo[2.2.2]-octylene, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1.2.3.4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl and fluorene-2,7-diyl, where the radicals a), b) and c) may be mono- or polysubstituted by halogen atoms, Z.sup.x, Z.sup.y identically or differently denote CH.sub.2CH.sub.2, CHCH, CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, COO, OCO, C.sub.2F.sub.4, CFCF, CHCHCH.sub.2O, or a single bond, Z.sup.1 on each occurrence independently of one another denotes COO, OCO, CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, CH.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CHCHCH.sub.2O, C.sub.2F.sub.4, CH.sub.2CF.sub.2, CF.sub.2CH.sub.2, CFCF, CHCF, CFCH, CHCH, CC or a single bond, L.sup.Y1, L.sup.Y2, L.sup.B1 and L.sup.B2 each, independently of one another, denote F, Cl, CF.sub.3 or CHF.sub.2, W denotes O or S, n is 0, 1 or 2, c is 0, 1 or 2, x and y independently are 0, 1 or 2, where x+y3.

6. The liquid crystal medium according to claim 1, wherein the medium further comprises one or more compounds of formula VII, ##STR00618## in which R.sup.71 and R.sup.72 denote H, F, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl, alkenyloxy each having 3 to 15 C atoms, where one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by ##STR00619## CC, CF.sub.2O, OCF.sub.2, CHCH, O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, X.sup.71, X.sup.72, X.sup.73, X.sup.74, X.sup.75 and X.sup.76, identically or differently, denote H or F, Z.sup.71 and Z.sup.72, identically or differently, denote CH.sub.2CH.sub.2 or a single bond.

7. The liquid crystal medium according to claim 1, wherein the medium further comprises one or more compounds of formula IV ##STR00620## in which R.sup.11 denotes a straight-chain alkyl radical having 1 to 12 C atoms or a branched or cyclic alkyl radical having 3 to 12 C atoms, or a straight-chain alkenyl radical having 2 to 12 C atoms or a branched alkenyl radical having 3 to 12 C atoms or a cyclic alkenyl radical having 5 to 12 C atoms, wherein one or more H atoms are optionally replaced by fluorine, R.sup.12 denotes a straight chain alkyl or alkoxy radical having 1 to 12 C atoms or a branched or cyclic alkyl or alkoxy radical having 3 to 12 C atoms, or a straight chain alkenyl radical having 2 to 12 C atoms or a branched alkenyl radical having 3 to 12 C atoms or a cyclic alkenyl radical having 5 to 12 C atoms, wherein one or more H atoms are optionally replaced by fluorine.

8. The liquid crystal medium according to claim 7, wherein the one or more compounds of formula IV comprise one or more compounds of formulae IVa and/or IVb, ##STR00621## in which R.sup.41 and R.sup.42 each, independently of one another, denote a straight-chain alkyl, alkoxy, alkenyl, alkoxyalkyl or alkenyloxy radical having up to 12 C atoms, ##STR00622## denotes ##STR00623## and Z.sup.4 denotes a single bond, CH.sub.2CH.sub.2, CHCH, CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, COO, OCO, C.sub.2F.sub.4, C.sub.4H.sub.8, or CFCF.

9. The liquid crystal medium according to claim 1, further comprising one or more compounds of formula V ##STR00624## in which R.sup.51, R.sup.52 denote alkyl having 1 to 7 C atoms, alkoxy having 1 to 7 C atoms, or alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7 C atoms, ##STR00625## identically or differently, denote ##STR00626## Z.sup.51, Z.sup.52 each, independently of one another, denote CH.sub.2CH.sub.2, CH.sub.2O, CHCH, CC, COO or a single bond, and n is 1 or 2.

10. The liquid crystal medium according to claim 1, further comprising one or more compounds of formula VIII ##STR00627## in which R.sup.81 and R.sup.82, identically or differently, denote H, halogen, CN, SCN, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl or alkenyloxy having 3 to 15 C atoms, where one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by ##STR00628## CC, CF.sub.2O, OCF.sub.2, CHCH, by O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, A.sup.0, A.sup.81, and A.sup.82, each, independently of one another, denote phenylene-1,4-diyl, in which one or two CH groups may be replaced by N and one or more H atoms may be replaced by halogen, CN, CH.sub.3, CHF.sub.2, CH.sub.2F, CF.sub.3, OCH.sub.3, OCHF.sub.2 or OCF.sub.3, cyclohexane-1,4-diyl, in which one or two non-adjacent CH.sub.2 groups may be replaced, independently of one another, by O and/or S and one or more H atoms may be replaced by F, cyclohexene-1,4-diyl, bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, tetrahydropyran-2,5-diyl or 1,3-dioxane-2,5-diyl; Z.sup.81 and Z.sup.82, each, independently of one another, denote CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, COO, OCO, C.sub.2H.sub.4, C.sub.2F.sub.4, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, CFHCFH, CFHCH.sub.2, CH.sub.2CFH, CF.sub.2CFH, CFHCF.sub.2, CHCH, CFCH, CHCF, CFCF, CC or a single bond; n denotes 0, 1, 2 or 3, and m denotes 0, 1, 2 or 3.

11. A liquid crystal display, comprising a liquid-crystal medium according to claim 1.

12. The liquid crystal display according to claim 11, wherein the display is configured to operate in the IPS or FFS mode.

13. A compound of the formula I ##STR00629## in which R.sup.11 and R.sup.12 identically or differently, denote H, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl, alkenyloxy each having 3 to 15 C atoms, where one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by ##STR00630## CHCH, CC, CF.sub.2O, OCF.sub.2, O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, and L.sup.11 and L.sup.12 denote H, F, Cl, CH.sub.3, CF.sub.3 or CHF.sub.2; wherein L.sup.11 and L.sup.12 do not both denote H and if one of L.sup.11 and L.sup.12 denotes F the other of L.sup.11 and L.sup.12 is not Cl.

14. A process for the production of the compound of the formula I of claim 13, comprising at least the step of elimination of water from the compound of the formula (3) ##STR00631## in which R.sup.11 and R.sup.12 identically or differently, denote H, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl, alkenyloxy each having 3 to 15 C atoms, where one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by ##STR00632## CHCH, CC, CF.sub.2O, OCF.sub.2, O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, and L.sup.11 and L.sup.12 denote H, F, Cl, CH.sub.3, CF.sub.3 or CHF.sub.2; wherein L.sup.11 and L.sup.12 do not both denote H and if one of L.sup.11 and L.sup.12 denotes F the other of L.sup.11 and L.sup.12 is not Cl.

15. A compound of the formula (3) prepared according to the process of claim 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0047] Herein, an alkyl radical and/or an alkoxy radical is taken to mean straight-chain or branched or cyclic alkyl. It is preferably straight-chain, has 2, 3, 4, 5, 6 or 7 C atoms and accordingly preferably denotes ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy, hexyloxy or heptyloxy, furthermore methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy or tetradecyloxy.

[0048] Herein, branched alkyl is preferably isopropyl, s-butyl, isobutyl, isopentyl, 2-methylbutyl, 2-methylhexyl or 2-ethylhexyl.

[0049] As used herein, cyclic alkyl is taken to mean straight-chain or branched alkyl or alkenyl having up to 12 C atoms, preferably alkyl having 1 to 7 C atoms, in which a group CH.sub.2 is replaced with a carbocyclic ring having 3 to 5 C atoms, very preferably selected from the group consisting of cyclopropylalkyl, cyclobutylalkyl, cyclopentylalkyl and cyclopentenylalkyl, wherein alkyl is straight chain alkyl having 1 to 5 C atoms.

[0050] Herein, oxaalkyl preferably denotes straight-chain 2-oxapropyl (methoxymethyl), 2-(ethoxymethyl) or 3-oxabutyl (=2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

[0051] Herein, alkenyl, i.e. an alkyl radical in which one CH.sub.2 group has been replaced by CHCH, may be straight-chain or branched. It is preferably straight-chain and has 2 to 10 C atoms. Accordingly, it denotes, in particular, vinyl, prop-1- or -2-enyl, but-1-, -2- or -3-enyl, pent-1-, -2-, -3- or -4-enyl, hex-1-, -2-, -3-, -4- or -5-enyl, hept-1-, -2-, -3-, -4-, -5- or -6-enyl, oct-1-, -2-, -3-, -4-, -5-, -6- or -7-enyl, non-1-, -2-,-3-, -4-, -5-, -6-, -7- or -8-enyl, dec-1-, -2-, -3-, -4-, -5-, -6-, -7-, -8- or -9-enyl.

[0052] Herein, an alkyl or alkenyl radical which is at least monosubstituted by halogen, is preferably straight-chain, and halogen is preferably F or Cl. In the case of polysubstitution, halogen is preferably F. The resultant radicals also include perfluorinated radicals. In the case of mono-substitution, the fluorine or chlorine substituent may be in any desired position, but is preferably in the -position.

[0053] Herein, a mono- or polyfluorinated alkyl or alkoxy radical having 1, 2 or 3 C atoms or a mono- or polyfluorinated alkenyl radical having 2 or 3 C atoms is particularly preferably F, Cl, CF.sub.3, CHF.sub.2, OCF.sub.3, OCHF.sub.2, OCFHCF.sub.3, OCFHCHF.sub.2, OCFHCHF.sub.2, OCF.sub.2CH.sub.3, OCF.sub.2CHF.sub.2, OCF.sub.2CHF.sub.2, OCF.sub.2CF.sub.2CHF.sub.2, OCF.sub.2CF.sub.2CHF.sub.2, OCFHCF.sub.2CF.sub.3, OCFHCF.sub.2CHF.sub.2, OCF.sub.2CF.sub.2CF.sub.3, OCF.sub.2CF.sub.2CClF.sub.2, OCClFCF.sub.2CF.sub.3, OCHCF.sub.2 or CHCF.sub.2, very particularly preferably F or OCF.sub.3, furthermore CF.sub.3, OCFCF.sub.2, OCHF.sub.2 or OCHCF.sub.2.

[0054] The compounds of the formula I are preferably selected from the compounds of the formulae I-1 to I-4

##STR00009##

in which R.sup.11 and R.sup.12 have the meanings defined above for formula I and preferably denote straight chain alkyl or alkoxy each having 1 to 7 C atoms, or straight chain alkenyl having 2 to 15 C atoms where one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by

##STR00010##

and very preferably denote straight chain alkyl having 1 to 7 C atoms or straight chain alkenyl having 1 to 7 C atoms.

[0055] More preferably the medium according to the invention comprises one or more compounds of the formula 1-1, very preferably selected from the compounds of the formulae I-1-1 to I-1-32

##STR00011## ##STR00012## ##STR00013##

in which R.sup.11 and R.sup.12 denote straight chain alkyl having 1 to 7 C atoms or straight chain alkenyl having 2 to 7 C atoms.

[0056] The compounds of the formula 1-2 are preferably selected from the compounds of the formulae I-2-1 to I-2-32:

##STR00014## ##STR00015## ##STR00016## ##STR00017##

[0057] The compounds of the formula 1-3 are preferably selected from the compounds of the formulae I-3-1 to I-3-32:

##STR00018## ##STR00019## ##STR00020##

[0058] The compounds of the formula 1-4 are preferably selected from the compounds of the formulae I-4-1 to I-4-32:

##STR00021## ##STR00022## ##STR00023##

[0059] Preferably, the medium comprises one or more compounds of formula II, preferably selected from the group of compounds of formulae II-1 to 11-3, very preferably from the group of compounds of the formulae II-1 and II-3

##STR00024##

in which the occurring groups have the respective meanings given under formula II above and in formula II-1 the radicals L.sup.23 and L.sup.24 denote, independently of each other, H or F and in formula II-2 preferably

##STR00025##

independently of each other, denote

##STR00026##

[0060] In formulae II-1, II-2 and II-3, L.sup.21 and L.sup.22 or L.sup.23 and L.sup.24 are preferably both F.

[0061] In another preferred embodiment in formulae II-1 and II-2, all of L.sup.21, L.sup.22, L.sup.23 and L.sup.24 denote F.

[0062] The compounds of formula II-1 are preferably selected from the group of compounds of the formulae II-1a to II-1h

##STR00027##

in which the occurring groups have the respective meanings given above.

[0063] In a preferred embodiment of the present invention the medium comprises one or more compounds selected from the group of compounds of the formulae II-1a to II-1 h wherein L.sup.21 and L.sup.22, and/or L.sup.23 and L.sup.24 are both F, respectively.

[0064] In another preferred embodiment the medium comprises compounds selected from the group of compounds of formulae II-1a to II-1h, wherein L.sup.21, L.sup.22, L.sup.23 and L.sup.24 all are F.

[0065] Especially preferred compounds of formula II-1 are

##STR00028##

in which R.sup.2 has the meaning given above.

[0066] Preferably the compounds of formula II-2 are selected from the group of compounds of formulae II-2a to II-2c

##STR00029##

in which the occurring groups have the respective meanings given above and preferably L.sup.21 and L.sup.22 are both F.

[0067] Preferably the compounds of formula II-3 are selected from the group of compounds of formulae II-3a to II-3e

##STR00030##

in which the occurring groups have the respective meanings given above and preferably [0068] L.sup.21 and L.sup.22 are both F and L.sup.23 and L.sup.24 are both H or [0069] L.sup.21, L.sup.22, L.sup.23 and L.sup.24 are all F.

[0070] Especially preferred compounds of formula II-3 are

##STR00031##

in which R.sup.2 has the meaning given above.

[0071] In addition to the preferred compounds of formula II above the medium optionally comprises one or more compounds of formula II selected from the compounds of the formulae IIA1 to IIA7:

##STR00032##

in which R.sup.2 and X.sup.2 have the meanings given in formula II or one of the preferred meanings given above and below.

[0072] Preferred compounds are those of formula IIA1, IIA2 and IIA3, very preferred those of formula IIA1 and IIA2.

[0073] In the compounds of formulae IIA1 to IIA7, R.sup.2 preferably denotes alkyl having 1 to 6 C atoms, very preferably ethyl or n-propyl, and X.sup.2 preferably denotes F or OCF.sub.3, very preferably F.

[0074] In another preferred embodiment of the present invention the medium comprises one or more compounds of formula III preferably selected from the group of formulae III-1 and III-2, preferably of formula III-2:

##STR00033##

in which the occurring groups and parameters have the respective meanings given under formula III above.

[0075] R.sup.3 preferably denotes alkyl having 1 to 7 C atoms or alkenyl having 2 to 7 C atoms.

[0076] Preferably the compounds of formula III-1 are selected from the group of compounds of formulae III-1a and III-1b

##STR00034##

in which the occurring groups have the respective meanings given above and L.sup.33 and L.sup.34, independently of each other, denote H or F.

[0077] The compounds of formula III-1a are preferably selected from the group of compounds of formulae III-1a-1 to III-1a-6

##STR00035##

in which R.sup.3 has the meaning given above.

[0078] Preferably the compounds of formula III-2 are selected from the group of compounds of formulae III-2a to III-2m

##STR00036## ##STR00037##

in which the occurring groups have the respective meanings given above and L.sup.35 and L.sup.36, independently of one another, denote H or F.

[0079] Preferably, the compounds of formula II-2a are selected from the group of compounds of formulae III-2a-1 to III-2a-4

##STR00038##

in which R.sup.3 has the meaning given above.

[0080] The compounds of formula III-2b are preferably selected from the group of compounds of formulae III-2b-1 and III-2b-2, preferably III-2b-2

##STR00039##

in which R.sup.3 has the meaning given above.

[0081] The compounds of formula II-2c, are preferably selected from the group of compounds of formulae III-2c-1 to III-2c-5

##STR00040##

in which R.sup.3 has the meaning given above.

[0082] The compounds of formulae III-2d and III-2e are preferably selected from the group of compounds of formulae III-2d-1 and III-2e-1

##STR00041##

in which R.sup.3 has the meaning given above.

[0083] The compounds of formula III-2f are preferably selected from the group of compounds of formulae III-2f-1 to III-2f-7

##STR00042##

in which R.sup.3 has the meaning given above.

[0084] The compounds of formula III-2g are preferably selected from the group of compounds of formulae III-2g-1 to III-2g-7

##STR00043##

in which R.sup.3 has the meaning given above.

[0085] The compounds of formula III-2h are preferably selected from the group of compounds of formulae III-2h-1 to III-2h-5

##STR00044##

in which R.sup.3 has the meaning given above.

[0086] The compounds of formula III-2i are preferably selected from the group of compounds of formulae III-2i-1 to III-2i-3

##STR00045##

in which R.sup.3 has the meaning given above.

[0087] The compounds of formula III-2j are preferably selected from the group of compounds of formulae III-2j-1 to III-2j-3

##STR00046##

in which R.sup.3 has the meaning given above.

[0088] The compounds of formula III-2k are preferably selected from the group of compounds of formulae III-2k-1 to III-2k-6

##STR00047##

in which R.sup.3 has the meaning given above.

[0089] The compounds of formula III-2I are preferably selected from the group of compounds of formulae III-2I-1 to III-2I-6

##STR00048##

in which R.sup.3 has the meaning given above.

[0090] The compounds of formula III-2m are preferably selected from the compounds of formula III-2m-1

##STR00049##

[0091] Alternatively, or in addition to the compounds of the formulae III-1 and/or III-2 the media according to the present invention optionally comprise one or more compounds of formula III-3,

##STR00050##

in which the groups and parameters have the respective meanings given under formula III above, preferably of formula III-3a

##STR00051##

in which the R.sup.3 has the meaning given above.

[0092] In addition to the preferred compounds of formula III above the medium optionally comprises one or more compounds selected from the group consisting of the formulae IIIA-1 to IIIA-21:

##STR00052## ##STR00053## ##STR00054##

in which R.sup.3 and X.sup.3 have the meanings given in formula III or one of the preferred meanings given above and below. Preferred compounds are those of formula IIIA1, IIIA4, IIIA6, IIIA16, IIIA19 and IIIA20.

[0093] In the compounds of formulae IIIA1 to IIIA21 R.sup.3 preferably denotes alkyl having 1 to 6 C atoms, very preferably ethyl or propyl, X.sup.3 preferably denotes F or OCF.sub.3, very preferably F.

[0094] Preferably, the medium according to the invention comprises one or more compounds of the formula IV

##STR00055##

in which [0095] R.sup.11 denotes a straight chain alkyl radical having 1 to 12 C atoms or a branched or cyclic alkyl radical having 3 to 12 C atoms, or a straight chain alkenyl radical having 2 to 12 C atoms or a branched alkenyl radical having 3 to 12 C atoms or a cyclic alkenyl radical having 5 to 12 C atoms, wherein one or more H atoms are optionally replaced by fluorine, preferably a straight chain alkyl radical having 1 to 12 C atoms, very preferably having 1 to 7 C atoms, [0096] R.sup.12 denotes a straight chain alkyl or alkoxy radical having 1 to 12 C atoms or a branched or cyclic alkyl or alkoxy radical having 3 to 12 C atoms, or a straight chain alkenyl radical having 2 to 12 C atoms or a branched alkenyl radical having 3 to 12 C atoms or a cyclic alkenyl radical having 5 to 12 C atoms, wherein one or more H atoms are optionally replaced by fluorine, preferably a straight chain alkenyl radical having 2 to 12 C atoms, very preferably having 2 to 7 C atoms.

[0097] The compounds of the formula IV are preferably selected from the group of the compounds of the formulae IV-1 to IV-4, very preferably of the formula IV-3

##STR00056##

in which [0098] alkyl and alkyl, independently of one another, denote alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms, [0099] alkoxy denotes alkoxy having 1 to 5 C atoms, preferably having 2 to 4 C atoms, [0100] alkenyl denotes an alkenyl radical having 2 to 5 C atoms, preferably having 2 to 4 C atoms, particularly preferably 2 C atoms, and [0101] alkenyl denotes an alkenyl radical having 2 to 5 C atoms, preferably having 2 to 4 C atoms, particularly preferably having 2 to 3 C atoms.

[0102] Preferably, the medium comprises one or more compounds of formula IV-1, preferably selected from the compounds of the formulae IV-1-1 to IV-1-6

##STR00057##

[0103] Preferably, the medium according to the invention comprises one or more compounds of the formulae IV-2-1 and/or IV-2-2

##STR00058##

[0104] Preferably, the medium according to the invention comprises a compound of formula IV-3, very preferably selected from the compounds of the formulae IV-3-1 to IV-3-6, in particular the compound of formula IV-3-2 and/or IV-3-6:

##STR00059##

[0105] Preferably, the medium according to the invention comprises a compound of formula IV-4, in particular selected from the compounds of the formulae IV-4-1 and IV-4-2:

##STR00060##

[0106] Preferably, the medium according to the invention comprises one or more compounds of the formula IVa and/or IVb, very preferably IVb

##STR00061##

in which [0107] R.sup.41 and R.sup.42each, independently of one another, denote a straight-chain alkyl, alkoxy, [0108] alkenyl, alkoxyalkyl or alkenyloxy radical having up to 12 C atoms, and

##STR00062##

denotes,

##STR00063## [0109] Z.sup.4 denotes a single bond, CH.sub.2CH.sub.2, CHCH, CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, COO, OCO, C.sub.2F.sub.4, C.sub.4H.sub.8, or CFCF.

[0110] Preferred compounds of the formula IVa are selected from the compounds of the formulae IVa-1 to IVa-4:

##STR00064##

in which [0111] alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1 to 6 C atoms.

[0112] The medium according to the invention preferably comprises at least one compound of the formula IVa-2.

[0113] Preferred compounds of the formula IVb are selected from the compounds of the formulae IVb-1 to IVb-3:

##STR00065##

in which [0114] alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1 to 6 C atoms, and [0115] alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2 to 6 C atoms.

[0116] Of the compounds of the formulae IVb-1 to IVb-3, the compounds of the formula IVb-2 are particularly preferred.

[0117] Very particularly preferred compounds of the formulae IVb are selected from the following compounds:

##STR00066##

[0118] The medium according to the invention particularly preferably comprises the compound IVb-2-3.

[0119] In a preferred embodiment, the medium according to the invention comprises one or more compounds of formula V

##STR00067##

in which [0120] R.sup.51, R.sup.52 denote alkyl having 1 to 7 C atoms, alkoxy having 1 to 7 C atoms, or alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7 C atoms,

##STR00068##

identically or differently, denote

##STR00069## [0121] Z.sup.51, Z.sup.52 each, independently of one another, denote CH.sub.2CH.sub.2, CH.sub.2O, CHCH, CC, COO or a single bond, and [0122] n is 1 or 2, [0123] where the compounds of the formulae I and CL are excluded.

[0124] The compounds of formula V are preferably selected from the compounds of the formulae V-1, V-2, V-3 and V-4:

##STR00070##

in which the groups occurring have the meanings given above for formula V.

[0125] The compounds of formula V-1 are preferably selected from the compounds of the formulae V-1-1 to V-1-8; [0126] the compounds of formula V-2 are preferably selected from the compounds of the formulae V-2-1 to V-2-4; and [0127] the compounds of formula V-3 are preferably selected from the compounds of the formulae V-3-1 to V-3-4:

##STR00071## ##STR00072##

in which R.sup.51 and R.sup.52 have the meanings indicated for formula V above.

[0128] R.sup.51 and R.sup.52 preferably each, independently of one another, denote straight-chain alkyl having 1 to 7 C atoms or alkenyl having 2 to 7 C atoms.

[0129] Very preferred compounds of the formula V-2-1 are selected from the compounds of the formulae V-2-1a to V-2-g

##STR00073##

[0130] Very preferred compounds of the formula V-2-2 are selected from the compounds of the formulae V-2-2a to V-2-2i

##STR00074##

[0131] Preferably, the medium according to the invention comprises one or more compounds of the formula CL

##STR00075## [0132] in which [0133] R.sup.L denotes H, a straight chain or branched alkyl or alkoxy radical having 1 to 15 C atoms, or a straight chain or branched alkenyl radical having 2 to 15 C atoms, where one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by

##STR00076## [0134] CC, CF.sub.2O, OCF.sub.2, CHCH, O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by halogen, [0135] X.sup.L denotes F, Cl, CN, CHF.sub.2, CF.sub.3, OCF.sub.3, or, identically or differently, has one of the meanings of R.sup.L, [0136] Y.sup.L denotes H, F, C or CH.sub.3.

[0137] The compounds of formula CL are preferably selected form the group of compounds of the formulae CL-1, CL-2 and CL-3:

##STR00077## [0138] in which [0139] R.sup.L1 and R.sup.L2, identically or differently, have the meanings given above for formula I and, preferably denote alkyl or alkenyl having 1 to 7 C atoms or 2 to 7 C atoms, respectively, in which a CH.sub.2 group may be replaced by cyclopropane-1,2-diyl, and R.sup.L2 alternatively denotes alkoxy having 1 to 5 C atoms.

[0140] Very preferred compounds of the formula CL are selected from the compounds of the formulae CL-3-1 to CL-3-12:

##STR00078## ##STR00079##

[0141] In a particularly preferred embodiment, the medium according to the invention comprises the compound CL-3-1 or CLP-3-3.

[0142] In a preferred embodiment of the present invention the medium additionally comprises one or more compounds of the formulae VI-1 to VI-9

##STR00080## [0143] in which [0144] R.sup.6 each, [0145] independently of one another, denote a straight-chain or branched alkyl or alkoxy radical that is unsubstituted or halogenated and has 1 to 15 C atoms, where one or more CH.sub.2 groups in these radicals may [0146] each be replaced, independently of one another, by

##STR00081##

CC, CF.sub.2O, CHCH, O, COO or OCO in such a way that O atoms are not linked directly to one another,

##STR00082##

independently of one another denote

##STR00083##

w each, independently of one another, denote an integer from 1 to 6.

[0147] In a preferred embodiment of the present invention the medium additionally comprises one or more compounds of the formula VII,

##STR00084##

in which [0148] R.sup.71 and R.sup.72 denote H, F, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl, alkenyloxy each having 3 to 15 C atoms, where one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by

##STR00085##

CF.sub.2O, OCF.sub.2, CHCH, O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, [0149] X.sup.71 to X.sup.76, identically or differently, denote H or F, preferably at least one of X.sup.71 to X.sup.76 denotes F, more preferably at least two of X.sup.71 to X.sup.76 denote F; [0150] Z.sup.71 and Z.sup.72, identically or differently, denote CH.sub.2CH.sub.2 or a single bond.

[0151] The compounds of the formula VII are preferably selected from the formulae VII-1 and VII-2:

##STR00086##

in which the occurring groups have the meanings given for formula VII.

[0152] The compounds of the formula VII-1 are preferably selected from the formulae VII-1-1 to VII-1-21, very preferably of the formula VII-1-4:

##STR00087## ##STR00088## ##STR00089##

in which R.sup.7 denotes a straight-chain alkyl or alkoxy radical having 1 to 6 C atoms, (O) denotes O or a single bond, and m is 0, 1, 2, 3, 4, 5 or 6 and n is 0, 1, 2, 3 or 4. R.sup.7 preferably denotes methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentoxy.

[0153] In the compounds of the formula VII-1-4, (0) preferably denotes O.

[0154] The compounds of the formula VII-2 are preferably selected from the formulae VII-2-1 to VII-2-15, very preferably of the formula VII-2-1:

##STR00090## ##STR00091##

in which R.sup.7 denotes a straight-chain alkyl or alkoxy radical having 1 to 6 C atoms, (0) denotes O or a single bond, and m is 0, 1, 2, 3, 4, 5 or 6 and n is 0, 1, 2, 3 or 4. R.sup.7 preferably denotes methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentoxy.

[0155] Preferably, the medium according to the invention comprises one or more compounds of the formula VIII:

##STR00092## [0156] in which [0157] R.sup.81 and R.sup.82, identically or differently, denote H, halogen, CN, SCN, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl or alkenyloxy having 3 to 15 C atoms, where one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by

##STR00093##

CC, CF.sub.2O, OCF.sub.2, CHCH, by O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, [0158] A.sup.0, A.sup.81, and A.sup.82, each, independently of one another, denote phenylene-1,4-diyl, in which one or two CH groups may be replaced by N and one or more H atoms may be replaced by halogen, CN, CH.sub.3, CHF.sub.2, CH.sub.2F, CF.sub.3, OCH.sub.3, OCHF.sub.2 or OCF.sub.3, cyclohexane-1,4-diyl, in which one or two non-adjacent CH.sub.2 groups may be replaced, independently of one another, by 0 and/or S and one or more H atoms may be replaced by F, cyclohexene-1,4-diyl, bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, tetrahydropyran-2,5-diyl or 1,3-dioxane-2,5-diyl; [0159] Z.sup.81 and Z.sup.82, each, independently of one another, denote CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, COO, OCO, C.sub.2H.sub.4, C.sub.2F.sub.4, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, CFHCFH, CFHCH.sub.2, [0160] CH.sub.2CFH, CF.sub.2CFH, CFHCF.sub.2, CHCH, CFCH, CHCF, CFCF, CC or a single bond; [0161] n denotes 0, 1, 2 or 3, preferably 0, 1 or 2, very preferably 0 or 1, particularly preferably 0; and [0162] m denotes 0, 1, 2 or 3, preferably 0, 1 or 2, very preferably 1 or 2, in particular 1. where the compounds of the formula I are excluded from formula VIII.

[0163] A.sup.81 and A.sup.82 in formula I preferably denote phenylene-1,4-diyl, which may also be mono- or polysubstituted by F, furthermore cyclohexane-1,4-diyl, cyclohexenylene-1,4-diyl, tetrahydropyran-2,5-diyl or 1,3-dioxane-2,5-diyl, very preferably phenylene-1,4-diyl which may also be mono- or polysubstituted by F, or cyclohexane-1,4-diyl. [0164] Z.sup.81 and Z.sup.82 in formula I preferably denote CF.sub.2O, OCF.sub.2 or a single bond, very preferably a single bond. [0165] A.sup.81 and A.sup.82 in formula I particularly preferably denote

##STR00094##

in which L denotes halogen, CF.sub.3 or CN, preferably F.

[0166] Preference is furthermore given to compounds of the formula VIII in which R.sup.81 and R.sup.82 each, independently of one another, denote H, F, or alkyl, alkoxy, alkenyl or alkynyl having 1 to 8, preferably 1 to 5, C atoms, each of which is optionally substituted by halogen, in particular by F.

[0167] R.sup.81 and R.sup.82 preferably denote H, optionally fluorinated alkyl or alkoxy having 1 to 7 C atoms, optionally fluorinated alkenyl or alkynyl having 2 to 7 C atoms, optionally fluorinated cycloalkyl having 3 to 12 C atoms.

[0168] Preferably, at least one of R.sup.81 and R.sup.82 is not H, particularly preferably both of R.sup.81 and R.sup.82 are not H. R.sup.81 is very particularly preferably alkyl. R.sup.82 is furthermore preferably H, [0169] alkyl or fluorine. Very particularly preferably, R.sup.81 is alkyl and R.sup.82 is H or alkyl. R.sup.81. R.sup.82 each, independently of one another, very particularly preferably denote unbranched alkyl having 1 to 5 C atoms. If R.sup.81 and R.sup.82 denote substituted alkyl, alkoxy, alkenyl or alkynyl, the total number of C atoms in the two groups R.sup.81 and R.sup.82 is preferably less than 10.

[0170] Preferred compounds of the formula VIII are selected from the following sub-formulae, more preferably from the compounds of the formula VIII-3:

##STR00095##

in which R.sup.81 and R.sup.82 have the meanings indicated above, L denotes F, and r, s and t independently are 0, 1, 2, 3, or 4. r preferably is 1 or 2, very preferably 2 and s and t independently are preferably 0 or 1, very preferably 0. R.sup.81 and R.sup.82 in particular independently denote n-alkyl having 1 to 5 C atoms.

[0171] In a first very preferred embodiment, the compounds of the formulae VIII-1 to VIII-6 are selected from the compounds of the formula VIII-1a to VIII-6a, in particular of the formula VIII-3a:

##STR00096##

in which R.sup.81, R.sup.82, L, r and s have the meanings defined above.

[0172] In a second very preferred embodiment, the compounds of the formulae VIII-1 to VIII-6 are selected from the compounds of the formula VIII-1b to VIII-5b, in particular of the formula VIII-2b:

##STR00097##

in which R.sup.1, R.sup.2, L, r and s have the meanings defined above.

[0173] In a third very preferred embodiment, the compounds of the formulae VIII-1 to VIII-6 are selected from the compounds of the formula VIII-1c to VIII-6c, in particular of the formula I3-c:

##STR00098##

in which R.sup.1, R.sup.2, L, r and s have the meanings defined above.

[0174] In a fourth very preferred embodiment, the compounds of the formulae VIII-1 to VIII-6 are selected from the compounds of the formula VIII-1d to VIII-6d, in particular of the formula VIII-3d:

##STR00099##

in which R.sup.1, R.sup.2, L, r and s have the meanings defined above.

[0175] In a particularly preferred embodiment, the medium according to the invention comprises one or more compounds selected from the group of the formulae VIII-1a to VIII-6a and one or more compounds selected from the group of the formulae VIII-1b to VIII-6b.

[0176] Very particularly preferably the medium comprises one or more compounds selected from the group of compounds of the formulae VIII-3a, VIII-2b, VIII-3c and VIII-3d:

##STR00100##

in which R.sup.81, R.sup.82, L and r have the meanings defined above and preferably r is 0.

[0177] Most preferred compounds of formula VIII include, in particular, one or more of the following:

##STR00101## ##STR00102## ##STR00103##

[0178] Alternatively, or additionally, the following compounds of formula VIII can be used:

##STR00104## ##STR00105## ##STR00106## ##STR00107##

[0179] The medium according to the invention optionally comprises one or more compounds with negative dielectric anisotropy, preferably selected from the group consisting of the formulae Y, B, BC, CR, PH-1 and PH-2:

##STR00108##

in which [0180] R.sup.Y1, R.sup.Y2, R.sup.B1, R.sup.B2, R.sup.CR1, R.sup.CR2, R.sup.P1, and R.sup.P2 each, independently of one another, [0181] denote H, an alkyl or alkoxy radical having 1 to 15 C atoms, where one [0182] or more CH.sub.2 groups in these radicals may each be replaced, [0183] independently of one another, by

##STR00109##

CHCH, CC, CF.sub.2O, OCF.sub.2, O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen,

##STR00110##

on each occurrence, independently of one another, denote [0184] a) 1,4-cyclohexenylene or 1,4-cyclohexylene radical, in which one or two non-adjacent CH.sub.2 groups may be replaced by O or S, [0185] b) a 1,4-phenylene radical, in which one or two CH groups may be replaced by N, or [0186] c) a radical from the group spiro[3.3]heptane-2,6-diyl, 1,4-bicyclo-[2.2.2]octylene, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl and fluorene-2,7-diyl, [0187] where the radicals a), b) and c) may be mono- or polysubstituted by halogen atoms, [0188] preferably

##STR00111## [0189] Z.sup.x, Z.sup.y identically or differently denote CH.sub.2CH.sub.2, CHCH, CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, COO, OCO, C.sub.2F.sub.4, CFCF, CHCHCH.sub.2O, or a single bond, preferably a single bond, [0190] Z.sup.1 on each occurrence independently of one another denotes COO, OCO, CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, CH.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CHCHCH.sub.2O, C.sub.2F.sub.4, CH.sub.2CF.sub.2, CF.sub.2CH.sub.2, CFCF, CHCF, CFCH, CHCH, CC or a single bond, preferably CH.sub.2O or a single bond, and [0191] L.sup.Y1, L.sup.Y2, L.sup.B1 and L.sup.B2 each, independently of one another, denote F, Cl, CF.sub.3 or CHF.sub.2, preferably H or F, most preferably F, and [0192] W denotes O or S, [0193] n is 0, 1 or 2, preferably 0 or 1, [0194] c is 0, 1 or 2, preferably 1 or 2, [0195] x and y independently are 0, 1 or 2, where x+y3.

[0196] The compounds of the formula Y are preferably selected from the group of compounds of the formulae YA, YB, YC and YD:

##STR00112## [0197] in which R.sup.2A, R.sup.2B, R.sup.2c and R.sup.2D each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals may be replaced by O, S,

##STR00113##

CC, CF.sub.2O, OCF.sub.2, OCO or OCO in such a way that O atoms are not linked directly to one another, [0198] L.sup.1 to L.sup.4 each, independently of one another, denote F, Cl, CF.sub.3 or CHF.sub.2, [0199] Y denotes H, F, Cl, CF.sub.3, CHF.sub.2 or CH.sub.3, preferably H or CH.sub.3, very preferably H, [0200] Z.sup.2, Z.sup.2B and Z.sup.2D each, independently of one another, denote a single bond, CH.sub.2CH.sub.2, CHCH, CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, COO, OCO, C.sub.2F.sub.4, CFCF or CHCHCH.sub.2O, [0201] (O) denotes 0 or a single bond, [0202] p denotes 0, 1 or 2, [0203] q denotes 0 or 1, and [0204] v denotes 1, 2, 3, 4, 5, or 6.

[0205] Preferred compounds of the formulae YA, YB, YC and YD are indicated below:

##STR00114## ##STR00115## ##STR00116## ##STR00117## ##STR00118## ##STR00119##

##STR00120## ##STR00121## ##STR00122## ##STR00123## ##STR00124##

in which the parameter a denotes 1 or 2, alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, and alkenyl denotes a straight-chain alkenyl radical having 2-6 C atoms, and (O) denotes an oxygen atom or a single bond. Alkenyl preferably denotes CH.sub.2CH, CH.sub.2CHCH.sub.2CH.sub.2, CH.sub.3CHCH, CH.sub.3CH.sub.2CHCH, CH.sub.3(CH.sub.2).sub.2CHCH, CH.sub.3(CH.sub.2).sub.3CHCH or CH.sub.3CHCH(CH.sub.2).sub.2.

[0206] Particularly preferred mixtures according to the invention comprise one or more compounds of the formulae YA-2, YA-8, YA-10, YA-16, YA-18, YA-40, YA-41, YA-42, YA-43, YB-2, YB-10, YB-16, YC-1, YD-4 and YD-10.

[0207] The proportion of compounds of the formulae YA and/or YB in the mixture as a whole is preferably at least 20% by weight.

[0208] Preferred media according to the invention comprise at least one compound of the formula YC-1,

##STR00125##

in which alkyl and alkyl* have the meanings indicated above, preferably in amounts of <5% by weight, in particular >3% by weight.

[0209] The compounds of formula B are preferably selected from the compounds of the formula B-1 and/or B-2

##STR00126## [0210] in which the occurring groups have the same meanings as given under formula B above and preferably [0211] R.sup.11 and R.sup.12 each, independently of one another, an alkyl, alkenyl or alkoxy radical having up to 15 C atoms, more preferably one or both of them denote an alkoxy radical and [0212] L.sup.11 and L.sup.12 each preferably denote F.

[0213] Preferably, the compounds of the formula B-1 selected from the group of compounds of formulae B-1-1 to B-1-11, preferably of formula B-1-6,

##STR00127## [0214] in which [0215] alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms, alkoxy and alkoxy* each, independently of one another, denote a straight-chain alkoxy radical having 1-6 C atoms, and L.sup.11 and L.sup.12 each, independently of one another, denote F or Cl, preferably both F.

[0216] Preferably, the compounds of the formula B-2 are selected from the group of compounds of formulae B-2-1 to B-2-10, preferably of formula B-2-6,

##STR00128## [0217] in which [0218] alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms, alkoxy and alkoxy* each, independently of one another, denote a straight-chain alkoxy radical having 1-6 C atoms, and L.sup.1 and L.sup.2 each, independently of one another, denote F or Cl, preferably both F.

[0219] Optionally the medium comprises one or more compounds of the formula BA-1 and/or BA-2

##STR00129## [0220] in which L.sup.11 and L.sup.12 have the same meanings as given under formula B, (O) denotes O or a single bond, [0221] R.sup.IIIA denotes alkyl or alkenyl having up to 7 C atoms or a group Cy-C.sub.mH.sub.2m, [0222] m and n are, identically or differently, 0, 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, very preferably 1, [0223] Cy denotes a cycloaliphatic group having 3, 4 or 5 ring atoms, which is optionally substituted with alkyl or alkenyl each having up to 3 C atoms, or with halogen or CN, and preferably denotes cyclopropyl, cyclobutyl or cyclopentyl.

[0224] The compounds of formula BA-1 and/or BA-2 are contained in the medium either alternatively or in addition to the compounds of formula B, preferably additionally.

[0225] Very preferred compounds of the formulae BA-1 and BA-2 are the following:

##STR00130##

in which alkoxy denotes a straight-chain alkoxy radical having 1-6 C atoms or alternatively (CH.sub.2).sub.nF in which n is 2,3,4, or 5, preferably C.sub.2H.sub.4F.

[0226] Alternatively, the medium comprises one or more compounds of the formula BAa-1-3

##STR00131##

in which alkenyl denotes straight chain alkenyl having 2 to 6 C atoms, preferably 4 C atoms, very preferably CH.sub.3CHCHCH.sub.2.

[0227] In a preferred embodiment of the present invention, the medium comprises one or more compounds of formula B-3

##STR00132## [0228] in which [0229] R.sup.11, R.sup.12 identically or differently, denote H, an alkyl or alkoxy radical having 1 to 15 C atoms, in which one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, by CC, CF.sub.2O, OCF.sub.2, CHCH,

##STR00133##

O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by halogen.

[0230] The compounds of formula B-3 are preferably selected from the group of compounds of the formulae B-3-1 to B-3-10:

##STR00134##

in which R.sup.12 denotes alkyl having 1 to 7 C-atoms, preferably ethyl, n-propyl or n-butyl, or alternatively cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl or alternatively (CH.sub.2).sub.nF in which n is 2,3,4, or 5, preferably C.sub.2H.sub.4F.

[0231] In a preferred embodiment of the present invention, the medium comprises one or more compounds of the formulae B-4 to B-6, preferably of formula B-5

##STR00135##

in which the occurring groups have the meanings given above, R.sup.11 preferably denotes straight-chain alkyl and R.sup.12 preferably denotes optionally fluorinated alkoxy, each having 1 to 7 C atoms.

[0232] In a preferred embodiment the media comprise one or more compounds of the formula I selected from the group of compounds of formulae B-7 to B-9, preferably of formula B-8,

##STR00136##

in which the parameters have the meanings given above, R.sup.11 preferably denotes straight-chain alkyl and R.sup.12 preferably denotes F or optionally fluorinated alkoxy each having 1 to 7 C atoms.

[0233] Particularly preferred compounds of the formulae BC, CR and PH-1 are the compounds BC-1 to BC-7, CR-1 to CR-5, and BP-1 to BP-7

##STR00137## ##STR00138## ##STR00139## [0234] in which [0235] alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1 to 6 C atoms, and [0236] alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2 to 6 C atoms.

[0237] More preference is given to mixtures comprising one, two or three compounds of the formula BC-2, BC-3, BP-2 and/or BP-3, very preferably BP-2 and/or BP-3, in particular BP-3.

[0238] In a preferred embodiment, the medium according to the invention comprises one or more HALS-stabilisers of the formula H:

##STR00140## [0239] in which [0240] Ar denotes a methylene group or an aromatic hydrocarbon group having 6 to 40 C atoms or a heteroaromatic hydrocarbon group having 4 to 40 C atoms; preferably an aromatic hydrocarbon group having 6 to 40 C atoms; [0241] Sp denotes a spacer group; [0242] R.sup.S denotes H, alkyl having 1 to 12 C atoms or alkenyl having 2 to 12 C atoms; [0243] Z.sup.S denotes O, C(O)O, (CH.sub.2).sub.z or (CH.sub.2).sub.zO, or a single bond; [0244] HA denotes

##STR00141## [0245] R.sup.H denotes H, O*, CH.sub.3, OH or OR.sup.S; [0246] R.sup.S1, R.sup.S2, RRs and R.sup.S4, identically or differently, denote alkyl having 1 to 6 C atoms, preferably having 1 to 3 C atoms, very preferably CH.sub.3; [0247] G denotes H or R.sup.S or a group Z.sup.S-HA; [0248] z is an integer from 1 to 6, and [0249] q is 2, 3 or 4, preferably 3 or 4;

[0250] The compounds of formula I are preferably selected from the compounds of the formulae H-1, H-2 and H-3:

##STR00142##

in which R.sup.H has the meanings given above and preferably denotes H or O, Sp on each occurrence, identically or differently, denotes a spacer group, and [0251] W denotes linear or branched, optionally unsaturated alkylene having 1 to 12 C atoms, in which one or more non-adjacent CH.sub.2 groups may be replaced with O.

[0252] Preferred compounds of formula H-1 are selected from the compounds of the formula H-1-1:

##STR00143##

in which R.sup.H has the meanings given above and preferably denotes H or O, and n is an integer from 0 to 12, preferably 5, 6, 7, 8 or 9, very preferably 7.

[0253] Preferred compounds of formula H-2 are selected from the compounds of the formula H-2-1:

##STR00144##

in which R.sup.H has the meanings given above and preferably denotes H or O, and n2, on each occurrence identically or differently, preferably identically, is an integer from 1 to 12, preferably 2, 3, 4, 5, or 6, very preferably 3, and R.sup.S on each occurrence identically or differently, preferably identically, denotes alkyl having 1 to 6 C atoms, preferably n-butyl.

[0254] Preferred compounds of formula H-3 are selected from the compounds of the formula H-3-1:

##STR00145##

in which R.sup.H has the meanings given above and preferably denotes H or O, and n is an integer from 0 to 12, preferably 5, 6, 7, 8 or 9, very preferably 7.

[0255] Preferably, the media according to the invention, comprise a stabilizer selected from the group of compounds of the formulae ST-4 to ST-49.

##STR00146## ##STR00147## ##STR00148## ##STR00149## [0256] in which [0257] R.sup.ST denotes H, an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by CC, CF.sub.2O, OCF.sub.2, [0258] CHCH,

##STR00150##

O, COO, OCO in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by halogen,

##STR00151##

denotes

##STR00152## ##STR00153## ##STR00154## ##STR00155## [0259] Z.sup.ST each, independently of one another, denote COO, OCO, CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, CH.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CHCH, [0260] CH.sub.2O, C.sub.2F.sub.4, CH.sub.2CF.sub.2, CF.sub.2CH.sub.2, CFCF, CHCF, CFCH, [0261] CHCH, CC or a single bond, [0262] L.sup.1 and L.sup.2 each, independently of one another, denote F, Cl, CF.sub.3 or CHF.sub.2, [0263] n is an integer from 0 to 12, preferably 5, 6, 7, 8 or 9, very preferably 7, [0264] n2, on each occurrence identically or differently, preferably identically, is an integer from 1 to 12, preferably 2, 3, 4, 5, or 6, very preferably 3, and [0265] R.sup.S on each occurrence identically or differently, preferably identically, denotes alkyl having 1 to 6 C atoms, preferably n-butyl, [0266] p denotes 1 or 2, [0267] q denotes 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0268] Of the compounds of the formula ST, special preference is given to the compounds of the formulae

##STR00156## [0269] in which n=1, 2, 3, 4, 5, 6 or 7, preferably n=1 or 7

##STR00157## [0270] in which n=1, 2, 3, 4, 5, 6 or 7, preferably n=3

##STR00158## [0271] in which n=1, 2, 3, 4, 5, 6 or 7, preferably n=3

##STR00159## ##STR00160##

[0272] In the compounds of the formulae ST-3a and ST-3b, n preferably denotes 3. In the compounds of the formula ST-2a, n preferably denotes 7.

[0273] Very particularly preferred mixtures according to the invention comprise one or more stabilizers from the group of the compounds of the formulae ST-2a-1, ST-3a-1, ST-3b-1, ST-8-1, ST-9-1 and ST-12:

##STR00161## ##STR00162##

[0274] The compounds of the formulae ST-1 to ST-19 are preferably each present in the liquid-crystal mixtures according to the invention in amounts of 0.005-0.5%, based on the mixture.

[0275] If the mixtures according to the invention comprise two or more compounds from the group of the compounds of the formulae ST-1 to ST-19, the concentration correspondingly increases to 0.01-1% in the case of two compounds, based on the mixtures.

[0276] However, the total proportion of the compounds of the formulae ST-1 to ST-19, based on the mixture according to the invention, should not exceed 2%.

[0277] In another preferred embodiment of the present invention the liquid-crystalline medium additionally comprises one or more polymerisable compounds. The polymerisable compounds are preferably selected from formula M

R.sup.aB.sup.1(Z.sup.bB.sup.2).sub.mR.sup.bM [0278] in which the individual radicals, on each occurrence identically or differently, and each, independently of one another, have the following meaning: [0279] R.sup.a and R.sup.b P, PSp, H, F, Cl, Br, I, CN, NO.sub.2, NCO, NCS, OCN, SCN, SF.sub.5 or straight-chain or branched alkyl having 1 to 25 C atoms, in which, in addition, one or more non-adjacent CH.sub.2 groups may each be replaced, independently of one another, by [0280] C(R.sup.0)C(R.sup.00), CC, N(R.sup.00), O, S, CO, COO, OCO, OCOO in such a way that O and/or S atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by F, C, Br, I, CN, P or PSp, where, if B.sup.1 and/or B.sup.2 contain a saturated C atom, R.sup.a and/or R.sup.b may also denote a radical which is spiro-linked to this saturated C atom, [0281] wherein at least one of the radicals R.sup.a and R.sup.b denotes or contains a group P or PSp, [0282] P a polymerisable group, [0283] Sp a spacer group or a single bond, [0284] B.sup.1 and B.sup.2 an aromatic, heteroaromatic, alicyclic or heterocyclic group, preferably having 4 to 25 ring atoms, which may also contain fused rings, and which is unsubstituted, or mono- or polysubstituted by L, [0285] Z.sup.b O, S, CO, COO, OCO, OCOO, OCH.sub.2, CH.sub.2O, SCH.sub.2, CH.sub.2S, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, (CH.sub.2).sub.n1, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, (CF.sub.2).sub.n1, CHCH, CFCF, CC, CHCHCOO, OCOCHCH, CR.sup.0R.sup.00 or a single bond, [0286] R.sup.0 and R.sup.00 each, independently of one another, denote H or alkyl having 1 to 12 C atoms, [0287] m denotes 0, 1, 2, 3 or 4, [0288] n1 denotes 1, 2, 3 or 4, [0289] L P, PSp, OH, CH.sub.2OH, F, C, Br, I, CN, NO.sub.2, NCO, NCS, OCN, SCN, C(O)N(R.sup.x).sub.2, C(O)Y.sup.1, C(O)R.sup.x, N(R.sup.x).sub.2, optionally substituted silyl, optionally substituted aryl having 6 to 20 C atoms, or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, [0290] alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, in which, in addition, one or more H atoms may be replaced by F, Cl, P or PSp, [0291] P and Sp have the meanings indicated above, [0292] Y.sup.1 denotes halogen, [0293] R.sup.x denotes P, PSp, H, halogen, straight-chain, branched or cyclic alkyl having 1 to 25 C atoms, in which, in addition, one or more non-adjacent CH.sub.2 groups may be replaced by O, S, CO, COO, OCO, OCOO in such a way that O and/or S atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by F, Cl, P or PSp, 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.

[0294] Particularly preferred compounds of the formula I are those in which B.sup.1 and B.sup.2 each, independently of one another, denote 1,4-phenylene, 1,3-phenylene, naphthalene-1,4-diyl, naphthalene-2,6-diyl, phenanthrene-2,7-diyl, 9,10-dihydro-phenanthrene-2,7-diyl, anthracene-2,7-diyl, fluorene-2,7-diyl, coumarin, flavone, where, in addition, one or more CH groups in these groups may be replaced by N, cyclohexane-1,4-diyl, in which, in addition, one or more non-adjacent CH.sub.2 groups may be replaced by 0 and/or S, 1,4-cyclohexenylene, bicycle[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, piperidine-1,4-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, indane-2,5-diyl or octahydro-4,7-methanoindene-2,5-diyl, where all these groups may be unsubstituted or mono- or polysubstituted by L as defined above.

[0295] Particularly preferred compounds of the formula M are those in which B.sup.1 and B.sup.2 each, independently of one another, denote 1,4-phenylene, 1,3-phenylene, naphthalene-1,4-diyl or naphthalene-2,6-diyl,

[0296] Very preferred compounds of formula M are selected from the following formulae:

##STR00163## ##STR00164## ##STR00165## ##STR00166##

in which the individual radicals, on each occurrence identically or differently, and each, independently of one another, have the following meaning: [0297] P.sup.1, P.sup.2, P.sup.3 a polymerisable group, preferably selected from vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxy, [0298] Sp.sup.1, Sp.sup.2, Sp.sup.3 a single bond or a spacer group where, in addition, one or more of the radicals P.sup.1Sp.sup.1-, P.sup.1Sp.sup.2- and P.sup.3Sp.sup.3- may denote R.sup.aa, with the proviso that at least one of the radicals P.sup.1Sp.sup.1-, P.sup.2Sp.sup.2 and P.sup.3Sp.sup.3- present is different from R.sup.aa, preferably denote (CH.sub.2).sub.p1, (CH.sub.2).sub.p1O, (CH.sub.2).sub.p1COO or (CH.sub.2).sub.p1OCOO, wherein p1 is an integer from 1 to 12, [0299] R.sup.aa H, F, Cl, CN or straight-chain or branched alkyl having 1 to 25 C atoms, in which, in addition, one or more non-adjacent CH.sub.2 groups may each be replaced, independently of one another, by C(R.sup.0)C(R.sup.00), CC, N(R.sup.0), O, S, CO, COO, OCO, OCOO in such a way that O and/or S atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by F, Cl, CN or P.sup.1Sp.sup.1-, particularly preferably straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, [0300] alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms (where the alkenyl and alkynyl radicals have at least two C atoms and the branched radicals have at least three C atoms), [0301] R.sup.0, R.sup.00 H or alkyl having 1 to 12 C atoms, [0302] R.sup.y and R.sup.z H, F, CH.sub.3 or CF.sub.3, [0303] X.sup.1, X.sup.2, X.sup.3 COO, OCO or a single bond, [0304] Z.sup.M1 O, CO, C(R.sup.yR.sup.z) or CF.sub.2CF.sub.2, [0305] Z.sup.M2, Z.sup.M3 COO, OCO, CH.sub.2O, OCH.sub.2, CF.sub.2O, OCF.sub.2 or (CH.sub.2).sub.n, where n is 2, 3 or 4, [0306] L F, Cl, CN or straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, [0307] alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms, [0308] L, L H, For Cl, [0309] r 0, 1, 2, 3 or 4, [0310] s 0, 1, 2 or 3, [0311] t 0.1 or 2, [0312] x 0 or 1.

[0313] Especially preferred are compounds of formulae M2 and M13.

[0314] Further preferred are trireactive compounds M15 to M31, in particular M17, M18, M19, M22, M23, M24, M25, M30 and M31.

[0315] In the compounds of formulae M1 to M31 the group

##STR00167##

in which L has one of the meanings indicated above and r denotes 0, 1, 2, 3 or 4, in particular denotes

##STR00168##

in which L on each occurrence, identically or differently, has one of the meanings given above or below, and is preferably F, Cl, CN, NO.sub.2, CH.sub.3, C.sub.2H.sub.5, C(CH.sub.3).sub.3, CH(CH.sub.3).sub.2, CH.sub.2CH(CH.sub.3)C.sub.2H.sub.5, OCH.sub.3, OC.sub.2H.sub.5, COCH.sub.3, COC.sub.2H.sub.5, COOCH.sub.3, COOC.sub.2H.sub.5, CF.sub.3, OCF.sub.3, OCHF.sub.2, OC.sub.2F.sub.5 or PSp, very preferably F, C, CN, CH.sub.3, C.sub.2H.sub.5, OCH.sub.3, COCH.sub.3, OCF.sub.3 or PSp, more preferably F, Cl, CH.sub.3, OCH.sub.3, COCH.sub.3 or OCF.sub.3, especially F or CH.sub.3.

[0316] Preferred compounds of formulae M1 to M31 are those in which P.sup.1, P.sup.2 and P.sup.3 denote an acrylate, methacrylate, oxetane or epoxy group, very preferably an acrylate or methacrylate group.

[0317] Further preferred compounds of formulae M1 to M31 are those in which Sp.sup.1, Sp.sup.2 and Sp.sup.3 are a single bond.

[0318] Further preferred compounds of formulae M1 to M31 are those in which one of Sp.sup.1, [0319] Sp.sup.2 and Sp.sup.3 is a single bond and another one of Sp.sup.1, Sp.sup.2 and Sp.sup.3 is different from a single bond.

[0320] Further preferred compounds of formulae M1 to M31 are those in which those groups Sp.sup.1, Sp.sup.2 and Sp.sup.3 that are different from a single bond denote (CH.sub.2).sub.s1X, wherein s1 is an integer from 1 to 6, preferably 2, 3, 4 or 5, and X is X is the linkage to the benzene ring and is O, OCO, COO, OCOO or a single bond.

[0321] Particular preference is given to liquid-crystalline media comprising one, two or three polymerisable compounds of formula M, preferably selected from formulae M1 to M31.

[0322] Further preferably the liquid-crystalline media according to the present invention comprise one or more polymerisable compounds selected from Table E below.

[0323] Preferably the proportion of polymerisable compounds in the liquid-crystalline medium, preferably selected from formula M and Table E, is from 0.01 to 5%, very preferably from 0.05 to 1%, most preferably from 0.1 to 0.5%.

[0324] It was observed that the addition of one or more polymerisable compounds to the liquid-crystalline medium, like those selected from formula M and Table E, leads to advantageous properties like fast response times. Such a liquid-crystalline medium is especially suitable for use in PSA displays where it shows low image sticking, a quick and complete polymerisation, the quick generation of a low pretilt angle which is stable after UV exposure, a high reliability, high VHR value after UV exposure, and a high birefringence. By appropriate selection of the polymerisable compounds, it is possible to increase the absorption of the liquid-crystalline medium at longer UV wavelengths, so that it is possible to use such longer UV wavelengths for polymerisation, which is advantageous for the display manufacturing process.

[0325] The polymerisable group P is a group which is suitable for a polymerisation reaction, such as, for example, free-radical or ionic chain polymerisation, polyaddition or polycondensation, or for a polymer-analogous reaction, for example addition or condensation onto a main polymer chain. Particular preference is given to groups for chain polymerisation, in particular those containing a CC double bond or CC triple bond, and groups which are suitable for polymerisation with ring opening, such as, for example, oxetane or epoxide groups.

[0326] Preferred groups P are selected from the group consisting of CH.sub.2CW.sup.1COO, CH.sub.2CW.sup.1CO,

##STR00169##

CH.sub.2CW.sup.2(O).sub.k3, CW.sup.1CHCO(O).sub.k3, CW.sup.1CHCONH, CH.sub.2CW.sup.1CONH, CH.sub.3CHCHO, (CH.sub.2CH).sub.2CHOCO, (CH.sub.2CHCH.sub.2).sub.2CHOCO, (CH.sub.2CH).sub.2CHO, (CH.sub.2CHCH.sub.2).sub.2N, (CH.sub.2CHCH.sub.2).sub.2NCO, HOCW.sup.2W.sup.3, HSCW.sup.2W.sup.3, HW.sup.2N, HOCW.sup.2W.sup.3NH, CH.sub.2CW.sup.1CONH, CH.sub.2CH(COO).sub.k1-Phe-(O).sub.k2, CH.sub.2CH(CO).sub.k1-Phe-(O).sub.k2, Phe-CHCH, HOOC, OCN and W.sup.4W.sup.5W.sup.6Si, in which W.sup.1 denotes H, F, Cl, CN, CF.sub.3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH.sub.3, W.sup.2 and W.sup.3 each, independently of one another, denote H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W.sup.4, W.sup.5 and W.sup.6 each, independently of one another, denote Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W.sup.7 and W.sup.a each, independently of one another, denote H, Cl or alkyl having 1 to 5 C atoms, Phe denotes 1,4-phenylene, which is optionally substituted by one or more radicals L as defined above which are other than PSp, k.sub.1, k.sub.2 and k.sub.3 each, independently of one another, denote 0 or 1, k.sub.3 preferably denotes 1, and k.sub.4 denotes an integer from 1 to 10.

[0327] Very preferred groups P are selected from the group consisting of CH.sub.2CW.sup.1COO, CH.sub.2CW.sup.1CO,

##STR00170##

CH.sub.2CW.sup.2O, CH.sub.2CW.sup.2, CW.sup.1CHCO(O).sub.k3, CW.sup.1CHCONH, CH.sub.2CW.sup.1CONH, (CH.sub.2CH).sub.2CHOCO, (CH.sub.2CHCH.sub.2).sub.2CHOCO, (CH.sub.2CH).sub.2CHO, (CH.sub.2CHCH.sub.2).sub.2N, (CH.sub.2CHCH.sub.2).sub.2NCO, CH.sub.2CW.sup.1CONH, CH.sub.2CH(COO).sub.k, -Phe(O).sub.k2, CH.sub.2CH(CO).sub.k1-Phe-(O).sub.k2, Phe-CHCH and W.sup.4W.sup.5W.sup.6Si, in which W.sup.1 denotes H, F, Cl, CN, CF.sub.3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH.sub.3, W.sup.2 and W.sup.3 each, independently of one another, denote H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W.sup.4, W.sup.5 and W.sup.6 each, independently of one another, denote Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W.sup.7 and W.sup.8 each, independently of one another, denote H, Cl or alkyl having 1 to 5 C atoms, Phe denotes 1,4-phenylene, k.sub.1, k.sub.2 and k.sub.3 each, independently of one another, denote 0 or 1, k.sub.3 preferably denotes 1, and k.sub.4 denotes an integer from 1 to 10.

[0328] Very particularly preferred groups P are selected from the group consisting of CH.sub.2CW.sup.1COO, in particular CH.sub.2CHCOO, CH.sub.2C(CH.sub.3)COO and CH.sub.2CFCOO, furthermore CH.sub.2CHO, (CH.sub.2CH).sub.2CHOCO, (CH.sub.2CH).sub.2CHO,

##STR00171##

[0329] Further preferred polymerisable groups P are selected from the group consisting of vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide, most preferably from acrylate and methacrylate.

[0330] If Sp is different from a single bond, it is preferably of the formula SpX, so that the respective radical PSp conforms to the formula PSpX, wherein [0331] Sp denotes alkylene having 1 to 20, preferably 1 to 12, C atoms, which is optionally mono- or polysubstituted by F, C, Br, I or CN and in which, in addition, one or more non-adjacent CH.sub.2 groups may each be replaced, independently of one another, by O, S, NH, N(R.sup.0), Si(R.sup.0R.sup.00), CO, COO, OCO, OCOO, SCO, COS, N(R.sup.00)COO, OCON(R.sup.0), N(R.sup.0)CON(R.sup.00), CHCH or CC in such a way that O and/or S atoms are not linked directly to one another, [0332] X denotes O, S, CO, COO, OCO, OCOO, CON(R.sup.0), N(R.sup.0)CO, N(R.sup.0)CON(R.sup.00), OCH.sub.2, CH.sub.2O, SCH.sub.2, CH.sub.2S, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, CF.sub.2CF.sub.2, CHN, NCH, NN, [0333] CHCR.sup.0, CY.sup.2CY.sup.3, CC, CHCHCOO, OCOCHCH or a single bond, [0334] R.sup.0 and R.sup.00 each, independently of one another, denote H or alkyl having 1 to 20 C atoms, and [0335] Y.sup.2 and Y.sup.3 each, independently of one another, denote H, F, Cl or CN.

[0336] X is preferably O, S, CO, COO, OCO, OCOO, CONR.sup.0, NR.sup.0CO, NR.sup.0CONR.sup.00 or a single bond.

[0337] Typical spacer groups Sp and SpX are, for example, (CH.sub.2).sub.p1, (CH.sub.2CH.sub.2O).sup.q1CH.sub.2CH.sub.2, CH.sub.2CH.sub.2SCH.sub.2CH.sub.2, CH.sub.2CH.sub.2NHCH.sub.2CH.sub.2 or (SiR.sup.0R.sup.00O).sub.p1, in which p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R.sup.0 and R.sup.00 have the meanings indicated above.

[0338] Particularly preferred groups Sp and SpX are (CH.sub.2).sub.p1, (CH.sub.2).sub.p1O, (CH.sub.2).sub.p1OCO, (CH.sub.2).sub.p1COO, (CH.sub.2).sub.p1OCOO, in which p1 and q1 have the meanings indicated above.

[0339] Particularly preferred groups Sp are, in each case straight-chain, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene, ethenylene, propenylene and butenylene.

[0340] For the production of PSA displays, the polymerisable compounds contained in the liquid-crystalline medium are polymerised or crosslinked (if one compound contains two or more polymerisable groups) by in-situ polymerisation in the liquid-crystalline medium between the substrates of the LC display, optionally while a voltage is applied to the electrodes.

[0341] The structure of the PSA displays according to the invention corresponds to the usual geometry for PSA displays, as described in the prior art cited at the outset. Geometries without protrusions are preferred, in particular those in which, in addition, the electrode on the colour filter side is unstructured and only the electrode on the TFT side has slots. Particularly suitable and preferred electrode structures for PS-VA displays are described, for example, in US 2006/0066793 A1.

[0342] The combination of compounds of the preferred embodiments mentioned above with the polymerised compounds described above causes low threshold voltages, low rotational viscosities and very good low-temperature stabilities in the liquid-crystalline media according to the invention at the same time as constantly high clearing points and high VHR values.

[0343] The use of liquid-crystalline media containing polymerisable compounds allows the rapid establishment of a particularly low pretilt angle in PSA displays. In particular, the liquid-crystalline media exhibit significantly shortened response times, in particular also the grey-shade response times, in PSA displays compared with the media from the prior art.

[0344] In further preferred embodiments, taken alone or in combination with one another, the medium according to the invention comprises the following compounds, where the acronyms are explained in Table D below: [0345] one, two or more compounds of formula I in a total concentration in the range of from 0.5% to 10%, preferably 1% to 7%, particularly preferably 2% to 5%; [0346] one or more compounds of formula II, preferably of formula II-1, more preferably of the sub-formulae II-1a and/or II-1f and/or II-1g and/or II-1 h, in particular formula II-1a-1 and II-1f-1 and II-1h-1, or formula II-1f-1 and II-1g-1 and II-1h-1, preferably in a total concentration in the range of from 3% to 20%, preferably from 5% to 18%, particularly preferably from 7% to 15%; [0347] and/or [0348] one or more compounds of formula III in a total concentration in the range of from 0.1% to 10%, preferably from 0.2% to 7%, more preferably from 0.3% to 2%, preferably selected from the group of compounds of formula III-2, more preferably of the formulae III-2c and/or III-2i and/or III-2I and/or III-2m, very preferably of the formulae III-2c-4 and/or III-2i-3 and/or III-2I-3 and/or III-2m-1, in particular of the formulae III-2i-3 and III-2m-1, where the concentration of the compound(s) of the formula III-2m-1 is very preferably 1% or less; [0349] and/or [0350] one or more compounds of the formula YA, preferably of the formula YA-2 and/or YA-10 in a total concentration in the range of from 1% to 10%, preferably 2% to 8%, particularly preferably 3% to 7%; [0351] and/or [0352] one or more compounds of the formula YD, preferably of the formula YD-7 and/or YD-10 in a total concentration in the range of from 1% to 10%, preferably 2% to 8%, particularly preferably 3% to 7%; [0353] and/or [0354] one or more compounds of the formula YB, preferably of the formulae YB-2 and/or YB-10 in a total concentration in the range of from 0.5% to 10%, preferably 1% to 7%, particularly preferably 2% to 5%; [0355] and/or [0356] one or more compounds of the formula I and YD and optionally YA, preferably selected from the compounds of the formulae YA-2, YA-10, YD-7 and YD-10 in a total concentration in the range of from 1% to 20%, preferably 3% to 17%, particularly preferably 4% to 14%; [0357] and/or [0358] one or more compounds of the formula B, preferably B-8, very preferably of the formula LB(S)-n-OT, in particular LB(S)-3-OT, in a total concentration in the range of from 0.1% to 10%, preferably 0.5% to 5%, particularly preferably 1% to 4%; [0359] and/or [0360] less than 5% of one or more compounds of the formula IV-1, preferably less than 3%, very preferably less than 1%; [0361] and/or [0362] one or more compounds of formula IV, preferably of the formula IV-3, in a total concentration in the range of from 20% to 70%, more preferably 30% to 60%, very preferably 33% to 50%, preferably selected from the compounds of the formulae IV-3-1 to IV-3-6, in particular selected from the compounds of formula IV-3-1, IV-3-2, IV-3-4 and IV-3-6; [0363] and/or [0364] 0.5% to 8%, preferably 1% to 6% of the compound IV-3-6 (CC-3-2V1) or IV-3-4 (CC-4-V1); [0365] and/or [0366] one or more compounds of formula IVa, preferably of formula IVa-2, preferably in a total concentration in the range of from 0.1% to 3%, more preferably from 0.2% to 2%; [0367] and/or [0368] one or more compounds of formula IVb, preferably of formula IVb-2, very preferably of formula IVb-2-3, preferably in a total concentration in the range of from 0.2% to 8%, more preferably from 0.5% to 7%, in particular from 1% to 6%; [0369] and/or [0370] one or more compounds of formula V, preferably selected from the group consisting of the compounds V-1-1, V-1-6, V-2-1, V-2-2, V-2-3, V-2-4, V-3-4 and V-4-1, preferably in a total concentration in the range of from 5% to 50%, preferably from 10% to 40%, in particular from 15% to 33%; [0371] and/or [0372] one or more compounds of formula CL, preferably selected from the formula CL-3, preferably in a total concentration in the range of from 1% to 15%, preferably from 2% to 12%, in particular from 3% to 10%; [0373] and/or [0374] one or more compounds of formula V and one or more compounds of formula CL, preferably in a total concentration in the range of from 5% to 50%, preferably from 10% to 40%, in particular from 15% to 33%; [0375] and/or [0376] one or more compounds of formula V-1-1 or IV-1-6, preferably selected from the compounds CCC-n-V, CCC-V-V and CVCC-n-m, preferably in a total concentration in the range of from 0.5% to 10%, preferably from 0.75% to 7%, in particular from 1% to 5%; [0377] and/or [0378] one or more compounds of formula V-2-1 and/or V-2-2, preferably CCP-n-m and/or CCP-Vn-m and/or CPP-n-m, very particularly selected from the group consisting of CCP-3-1, CCPV-1, and CCP-V2-1, preferably in a total concentration in the range of from 8% to 20%, more preferably from 12% to 17%, very preferably from 15% to 27%; [0379] and/or [0380] one or more compounds of formula VII, preferably of the formula VII-1-20 and/or VII-1-21, preferably in a total concentration in the range of from 1% to 15%, preferably from 2% to 10%, in particular from 3% to 7%; [0381] and/or [0382] one or more compounds of formula VIII, preferably selected from the compounds of the formula VIII-3, more preferably VIII-3a, preferably in a total concentration in the range of from 2% to 20%, preferably from 5% to 17%, in particular from 8% to 14%; The liquid-crystalline media according to the invention, while retaining the nematic phase down to 20 C. and preferably down to 30 C., particularly preferably down to 40 C., and the clearing point 75 C., preferably 79 C., at the same time allow rotational viscosities , of 80 mPa.Math.s, particularly preferably 70 mPa.Math.s, to be achieved, enabling excellent MLC displays having fast response times. The rotational viscosities are determined at 20 C.

[0383] The dielectric anisotropy of the liquid-crystalline media according to the invention at 20 C. and 1 kHz is preferably 1.5, preferably in the range of from 1.5 to 8, more preferably from 2.0 to 6.0, very preferably from 2.5 to 4.6 and particularly preferably from 3.0 to 4.4.

[0384] The birefringence n of the liquid-crystalline media according to the invention is preferably from 0.080 to 0.140, very preferably from 0.090 to 0.135, in particular from 0.091 to 0.132.

[0385] In a preferred embodiment of the present invention the medium has a birefringence of from 0.080 to 0.100, very preferably from 0.085 to 0.098, in particular from 0.090 to 0.094.

[0386] In a preferred embodiment of the present invention the medium has a birefringence of from 0.110 to 0.130, very preferably from 0.119 to 0.128, in particular from 0.120 to 0.123.

[0387] In a preferred embodiment of the present invention the medium has a birefringence of from 0.120 to 0.140, very preferably from 0.125 to 0.135, in particular from 0.129 to 0.132.

[0388] The rotational viscosity .sub.1 of the liquid-crystalline media according to the invention is preferably 120 mPa s, more preferably 110 mPa s, very preferably 105 mPa s.

[0389] The ratio .sub.1/K.sub.1 of the liquid-crystalline media according to the invention is preferably 5.5 mPa.Math.s/pN, more preferably 5.3 mPa.Math.s/pN, very preferably 5.0 mPa.Math.s/pN.

[0390] Herein, the structures of the mesogenic compounds are indicated by means of abbreviations, also referred to as acronyms. In these acronyms, the chemical formulae are abbreviated as follows using Tables A to C below. All groups C.sub.nH.sub.2n+1, C.sub.mH.sub.2m+1 and C.sub.1H.sub.2l+1, and C.sub.nH.sub.2n1, C.sub.mH.sub.2m1, and C.sub.1H.sub.2l1 denote straight-chain alkyl or alkylene, respectively, in each case having n, m or l C atoms, wherein n and m, independently are 1, 2, 3, 4, 5, 6 or 7 and l is 1, 2 or 3. Table A lists the codes used for the ring elements of the core structures of the compounds, while Table B and Table C show the linking groups and end groups. Table D shows illustrative structures of compounds with their respective abbreviations.

TABLE-US-00001 TABLE A Ring elements C [00172] D [00173] DI [00174] A [00175] AI [00176] G [00177] GI [00178] U [00179] UI [00180] U(1) [00181] U(1)I [00182] Y [00183] Y(1) [00184] M [00185] MI [00186] N [00187] NI [00188] K [00189] KI [00190] L [00191] LI [00192] F [00193] FI [00194] P [00195] P(o) [00196] P(i3) [00197] PI(o) [00198] O [00199] S [00200] cpS [00201] B [00202] B(S) [00203] B(P) [00204] B(A) [00205]

TABLE-US-00002 TABLE B Linking groups E CH.sub.2CH.sub.2 Z COO V CHCH ZI OCO X CFCH O CH.sub.2O XI CHCF OI OCH.sub.2 B CFCF Q CF.sub.2O T CC QI OCF.sub.2 W CF.sub.2CF.sub.2

TABLE-US-00003 TABLE C End groups Used alone Left-hand side Right-hand side -n- C.sub.nH.sub.2n+1 -n C.sub.nH.sub.2n+1 -nO C.sub.nH.sub.2n+1O On OC.sub.nH.sub.2n+1 V CH.sub.2CH V CHCH.sub.2 -nV C.sub.nH.sub.2n+1CHCH -nV C.sub.nH.sub.2nCHCH.sub.2 Vn- CH.sub.2CH C.sub.nH.sub.2n+1 Vn CHCHC.sub.nH.sub.2n+1 -nVm- C.sub.nH.sub.2n+1CHCHC.sub.mH.sub.2m -nVm C.sub.nH.sub.2nCHCHC.sub.mH.sub.2m+1 N NC N CN S SCN S NCS F F F F Cl Cl Cl Cl -M- CFH.sub.2 -M CFH.sub.2 -D- CF.sub.2H -D CF.sub.2H -T- CF.sub.3 -T CF.sub.3 -MO CFH.sub.2O OM OCFH.sub.2 -DO CF.sub.2HO OD OCF.sub.2H -TO CF.sub.3O OT OCF.sub.3 -FXO CF.sub.2CHO OXF OCHCF.sub.2 -A- HCC -A CCH -nA- C.sub.nH.sub.2n+1CC -An CCC.sub.nH.sub.2n+1 NA- NCCC -AN CCCN -(cn)- [00206] -(cn) [00207] -(cn)m- [00208] -m(cn) [00209] -(c5-1en)m- [00210] -m(c5-1en) [00211] -(c5-2en)m- [00212] -m(c5-2en) [00213] -(c5-3en)m- [00214] -m(c5-3en) [00215]

TABLE-US-00004 - . . . A . . . - CC - . . . A . . . - CC - . . . V . . . - CHCH - . . . V . . . - CHCH . . . . Z . . . - COO - . . . Z . . . - COO - . . . ZI . . . - OCO . . . . ZI . . . - OCO - . . . K . . . - CO - . . . K . . . - CO - . . . W . . . - CFCF - . . . W . . . - CFCF
in which n and m each denote integers, and the three dots . . . are placeholders for other abbreviations from this table.

TABLE-US-00005 TABLE D [00216] CPn-F [00217] CPn-Cl [00218] GP-n-F [00219] GP-n-Cl [00220] CCP-n-OT [00221] CCG-n-OT [00222] CLP-n-T [00223] CCG-n-F [00224] CCG-VF [00225] CCG-nV-F [00226] CCUn-F [00227] CCEP-n-F [00228] CCEU-n-F [00229] CCEU-n-F [00230] CCEP-n-OT [00231] CDU-n-F [00232] CPG-n-F [00233] CPU-n-F [00234] CPU-n-OXF [00235] CGG-n-F [00236] CGG-n-OD [00237] CGU-n-F [00238] PGU-n-F [00239] GGP-n-F [00240] GGP-n-Cl [00241] GIGIP-n-F [00242] GIGIP-n-Cl [00243] CCPU-n-F [00244] CCGU-n-F [00245] CPGU-n-F [00246] CPGU-n-OT [00247] PPGU-n-F [00248] DPGU-n-F [00249] CCZU-n-F [00250] PUZU-n-F [00251] CCQG-n-F [00252] CCQU-n-F [00253] ACQU-n-F [00254] PUQU-n-F [00255] CDUQU-n-F [00256] CPUQU-n-F [00257] CGUQU-n-F [00258] PGUQU-n-F [00259] PGUQU(1)-n-F [00260] APUQU-n-F [00261] APUQU(1)-n-F [00262] DPUQU-n-F [00263] DGUQU-n-F [00264] CPUn-F [00265] DAUQU-n-F [00266] CLUQU-n-F [00267] ALUQU-n-F [00268] DLUQU-n-F [00269] LGPQU-n-F [00270] CC-n-m [00271] CC-n-Om [00272] CCn-V [00273] CC-n-Vm [00274] CCn-IV [00275] CC-n-IVm [00276] CCVV [00277] CCVIV [00278] CCV-Vm [00279] CC-Vk-IV [00280] CC-nV-IV [00281] CC-nV-Vm [00282] CCn-VV [00283] CC-n-VVm [00284] CVCn-V [00285] CVC-n-Vm [00286] CP-n-m [00287] CP-n-Om [00288] PP-n-m [00289] PP-n-Om [00290] CCP-n-m [00291] CCP-n-Om [00292] CCPV-m [00293] CCP-nV-m [00294] CCPVI-m [00295] CCP-nVI-m [00296] CCOC-n-m [00297] CCVC-n-m [00298] CCVCn-V [00299] CCVCn-IV [00300] CLP-n-m [00301] CLP-V-n [00302] CPP-n-m [00303] CPG-n-m [00304] CGP-n-m [00305] PGP-n-m [00306] PGP-n-IV [00307] PGP-n-IVm [00308] CCZPC-n-m [00309] CPPC-n-m [00310] CGPC-n-m [00311] CPGP-n-m [00312] CYV-n [00313] CYV-On [00314] CY-nV-m [00315] CY-nV-Om [00316] CYVI-m [00317] CYVI-Om [00318] CY-nVI-m [00319] CY-nVI-Om [00320] PYV-n [00321] PYV-On [00322] PY-nV-m [00323] PY-nV-Om [00324] PYVI-m [00325] PYVI-Om [00326] PY-nVI-m [00327] PY-nVI-Om [00328] CCYV-n [00329] CCYV-On [00330] CCY-nV-m [00331] CCY-nV-Om [00332] CCYVI-m [00333] CCYVI-Om [00334] CCY-nVI-m [00335] CCY-nVI-Om [00336] CPYV-n [00337] CPYV-On [00338] CPY-nV-m [00339] CPY-nV-Om [00340] CPYVI-m [00341] CPYVI-Om [00342] CPY-nVI-k [00343] CPY-nVI-Om [00344] CY-n-m [00345] CY-n-Om [00346] CVY-n-m [00347] CVYV-n [00348] CZY-n-Om [00349] COY-n-m [00350] COY-n-Om [00351] Y-n-m [00352] Y-n-Om [00353] Y-nO-Om [00354] PY-n-m [00355] PY-n-Om [00356] CCY-n-m [00357] CCY-n-Om [00358] CCY-n-mOI [00359] CCZY-n-Om [00360] CCOY-n-m [00361] CCOY-n-Om [00362] CLOY-n-Om [00363] CLOY(1)-n-Om [00364] CPY-n-m [00365] CPY-n-Om [00366] PYP-n-m [00367] PYP-n-V [00368] PYP-n-IV [00369] PYP-n-Vm [00370] PYP-n-IVm [00371] PYP-n-(c5) [00372] PYP-n-m(c3) [00373] CP(F,Cl)-n-Om [00374] CLY-n-m [00375] CLY-n-Om [00376] AILOY-n-Om [00377] CKn-F [00378] B-n-m [00379] B-n-IV [00380] B-Vn-IV [00381] B-n-Om [00382] B-nO-Om [00383] CB-n-Om [00384] PB-n-Om [00385] B(S)-nO-Om [00386] COB(S)-n-Om [00387] B(S)-(c3)nO-Om [00388] B(S)-(c5)nO-Om [00389] B(S)-(c5)nO-Om(c3) [00390] B(S)-(c5)IO-OmVn [00391] COB(S)-n-Om(c5) [00392] LY-(c5)-Om [00393] B(S)-(c5-3en)nO-Om [00394] LB(S)-n-F [00395] LB(S)-n-OT [00396] B(P)-n-m [00397] B(P)-n-Om [00398] B(P)-n-Om [00399] B(P)-nO-Om [00400] B(P)-(c5)nO-Om [00401] B(A)-nO-Om

[0391] In a preferred embodiment of the present invention, the media comprise one or more compounds selected from the group of the compounds of Table D.

[0392] Table E shows chiral dopants which are preferably employed in the mixtures according to the invention.

TABLE-US-00006 TABLE E [00402] C 15 [00403] CB 15 [00404] CM 21 [00405] CM 44 [00406] CM 45 [00407] CM 47 [00408] CC [00409] CN [00410] R/S-811 [00411] R/S-1011 [00412] R/S-2011 [00413] R/S-3011 [00414] R/S-4011 [00415] R/S-5011

[0393] Preferably, the media according to the invention comprise one or more compounds selected from the group of the compounds from Table E.

Table F

[0394] Table F shows illustrative reactive mesogenic compounds (RM) which can be used in the LC media in accordance with the present invention.

TABLE-US-00007 [00416] RM-1 [00417] RM-2 [00418] RM-3 [00419] RM-4 [00420] RM-5 [00421] RM-6 [00422] RM-7 [00423] RM-8 [00424] RM-9 [00425] RM-10 [00426] RM-11 [00427] RM-12 [00428] RM-13 [00429] RM-14 [00430] RM-15 [00431] RM-16 [00432] RM-17 [00433] RM-18 [00434] RM-19 [00435] RM-20 [00436] RM-21 [00437] RM-22 [00438] RM-23 [00439] RM-24 [00440] RM-25 [00441] RM-26 [00442] RM-27 [00443] RM-28 [00444] RM-29 [00445] RM-30 [00446] RM-31 [00447] RM-32 [00448] RM-33 [00449] RM-34 [00450] RM-35 [00451] RM-36 [00452] RM-37 [00453] RM-38 [00454] RM-39 [00455] RM-40 [00456] RM-41 [00457] RM-42 [00458] RM-43 [00459] RM-44 [00460] RM-45 [00461] RM-46 [00462] RM-47 [00463] RM-48 [00464] RM-49 [00465] RM-50 [00466] RM-51 [00467] RM-52 [00468] RM-53 [00469] RM-54 [00470] RM-55 [00471] RM-56 [00472] RM-57 [00473] RM-58 [00474] RM-59 [00475] RM-60 [00476] RM-61 [00477] RM-62 [00478] RM-63 [00479] RM-64 [00480] RM-65 [00481] RM-66 [00482] RM-67 [00483] RM-68 [00484] RM-69 [00485] RM-70 [00486] RM-71 [00487] RM-72 [00488] RM-73 [00489] RM-74 [00490] RM-75 [00491] RM-76 [00492] RM-77 [00493] RM-78 [00494] RM-79 [00495] RM-80 [00496] RM-81 [00497] RM-82 [00498] RM-83 [00499] RM-84 [00500] RM-85 [00501] RM-86 [00502] RM-87 [00503] RM-88 [00504] RM-89 [00505] RM-90 [00506] RM-91 [00507] RM-92 [00508] RM-93 [00509] RM-94 [00510] RM-95 [00511] RM-96 [00512] RM-97 [00513] RM-98 [00514] RM-99 [00515] RM-100 [00516] RM-101 [00517] RM-102 [00518] RM-103 [00519] RM-104 [00520] RM-105 [00521] RM-106 [00522] RM-107 [00523] RM-108 [00524] RM-109 [00525] RM-110 [00526] RM-111 [00527] RM-112 [00528] RM-113 [00529] RM-114 [00530] RM-115 [00531] RM-116 [00532] RM-117 [00533] RM-118 [00534] RM-119 [00535] RM-120 [00536] RM-121 [00537] RM-122 [00538] RM-123 [00539] RM-124 [00540] RM-125 [00541] RM-126 [00542] RM-127 [00543] RM-128 [00544] RM-129 [00545] RM-130 [00546] RM-131 [00547] RM-132 [00548] RM-133 [00549] RM-134 [00550] RM-135 [00551] RM-136 [00552] RM-137 [00553] RM-138 [00554] RM-139 [00555] RM-140 [00556] RM-141 [00557] RM-142 [00558] RM-143 [00559] RM-144 [00560] RM-145 [00561] RM-146 [00562] RM-147 [00563] RM-148 [00564] RM-149 [00565] RM-150 [00566] RM-151 [00567] RM-152 [00568] RM-153 [00569] RM-154 [00570] RM-155 [00571] RM-156 [00572] RM-157 [00573] RM-158 [00574] RM-159 [00575] RM-160 [00576] RM-161 [00577] RM-162 [00578] RM-163 [00579] RM-164 [00580] RM-165 [00581] RM-166 [00582] RM-167 [00583] RM-168 [00584] RM-169 [00585] RM-170 [00586] RM-171 [00587] RM-172 [00588] RM-173 [00589] RM-174 [00590] RM-175 [00591] RM-176 [00592] RM-177 [00593] RM-178 [00594] RM-179 [00595] RM-180 [00596] RM-181 [00597] RM-182 [00598] RM-183

[0395] In a preferred embodiment, the mixtures according to the invention comprise one or more polymerizable compounds, preferably selected from the polymerizable compounds of the formulae RM-1 to RM-182. Of these, compounds RM-1, RM-4, RM-8, RM-17, RM-19, RM-35, RM-37, RM-39, RM-40, RM-41, RM-48, RM-52, RM-54, RM-57, RM-58, RM-64, RM-74, RM-76, RM-88, RM-91, RM-102, RM-103, RM-109, RM-116, RM-117, RM-120, RM-121, RM-122, RM-139, RM-140, RM-142, RM-143, RM-145, RM-146, RM-147, RM-149, RM-156 to RM-163, RM-169, RM-170 and RM-171 to RM-183 are particularly preferred.

Working Examples

[0396] The following examples are intended to explain the invention without limiting it. In the examples, m.p. denotes the melting point and T.sub.(NI) denotes the clearing point of a liquid-crystalline substance in degrees Celsius; Furthermore: C denotes crystalline solid state, S denotes smectic phase (the index denotes the phase type), N denotes nematic state, Ch denotes cholesteric phase, I denotes isotropic phase, T.sub.g denotes glass-transition temperature. The number between two symbols indicates the conversion temperature in degrees Celsius.

[0397] The host mixture used for determination of the optical anisotropy n of single compounds is the commercial mixture ZLI-4792 (Merck KGaA). The dielectric anisotropy is determined using commercial mixture ZLI-2857. The physical data of the compound to be investigated are obtained from the change in the dielectric constants of the host mixture after addition of the compound to be investigated and extrapolation to 100% of the compound employed. In general, 10% of the compound to be investigated are dissolved in the host mixture, depending on the solubility.

[0398] Unless indicated otherwise, parts or percent data denote parts by weight or percent by weight.

[0399] Above and below: [0400] V.sub.o denotes threshold voltage, capacitive [V] at 20 C., [0401] n.sub.e denotes extraordinary refractive index at 20 C. and 589 nm, [0402] n.sub.o denotes ordinary refractive index at 20 C. and 589 nm, [0403] n denotes optical anisotropy (birefringence) at 20 C. and 589 nm, [0404] .sub. denotes dielectric permittivity perpendicular to the director at 20 C. and 1 kHz, [0405] denotes dielectric permittivity parallel to the director at 20 C. and 1 kHz, [0406] denotes dielectric anisotropy at 20 C. and 1 kHz, [0407] cl.p., T(N,l) denotes clearing point [ C.], [0408] .sub.1 denotes rotational viscosity measured at 20 C. [mPa.Math.s], [0409] K.sub.1 denotes elastic constant, splay deformation at 20 C. [pN], [0410] K.sub.2 denotes elastic constant, twist deformation at 20 C. [pN], [0411] K.sub.3 denotes elastic constant, bend deformation at 20 C. [pN], [0412] K.sub.av denotes the average elastic constant defined as K.sub.av=(1.5K.sub.1+K.sub.3) at 20 C. [pN], and [0413] LTS denotes low-temperature stability (nematic phase), determined in test cells or in the bulk, as specified.

[0414] Unless explicitly noted otherwise, all values indicated in the present application for temperatures, such as, for example, the melting point T(C,N), the transition from the smectic (S) to the nematic (N) phase T(S,N) and the clearing point T(N,l) or cl.p., are indicated in degrees Celsius ( C.).

[0415] The term threshold voltage for the present invention relates to the capacitive threshold (V.sub.0), also called the Freedericksz threshold, unless explicitly indicated otherwise. In the examples, as is generally usual, the optical threshold can also be indicated for 10% relative contrast (V.sub.10).

[0416] The display used for measurement of the capacitive threshold voltage consists of two plane-parallel glass outer plates at a separation of 20 m, which each have on the insides an electrode layer and an unrubbed polyimide alignment layer on top, which cause a homeotropic edge alignment of the liquid-crystal molecules.

[0417] The display or test cell used for measurement of the tilt angle consists of two plane-parallel glass outer plates at a separation of 4 m, which each have on the insides an electrode layer and a polyimide alignment layer on top, where the two polyimide layers are rubbed antiparallel to one another and cause a homeotropic edge alignment of the liquid-crystal molecules.

[0418] The polymerisable compounds are polymerised in the display or test cell by irradiation with UV light of defined intensity for a prespecified time, with a voltage simultaneously being applied to the display (usually 10 V to 30 V alternating current, 1 kHz). In the examples, unless indicated otherwise, a metal halide lamp and an intensity of 100 mW/cm.sup.2 is used for polymerisation. The intensity is measured using a standard meter (Hoenle UV-meter high end with UV sensor).

[0419] The tilt angle is determined using the Mueller Matrix Polarimeter AxoScan from Axometrics. A low value (i.e. a large deviation from the 90 angle) corresponds to a large tilt here.

[0420] Unless stated otherwise, the term tilt angle means the angle between the LC director and the substrate, and LC director means in a layer of LC molecules with uniform orientation the preferred orientation direction of the optical main axis of the LC molecules, which corresponds, in case of calamitic, uniaxially positive birefringent LC molecules, to their molecular long axis.

[0421] Unless indicated otherwise, the VHR is determined at 20 C. (VHR.sub.20) and after 5 minutes in an oven at 100 C. (VHR.sub.100) in a commercially available instrument Model LCM-1 (00004) from TOYO Corporation, Japan. The voltage used has a frequency of in a range from 1 Hz to 60 Hz, unless indicated more precisely.

[0422] The stability to UV irradiation is investigated in a Suntest CPS+, a commercial instrument from Heraeus, Germany, using a Xenon lamp NXE1500B. The sealed test cells are irradiated for 2.0 h, unless explicitly indicated, without additional heating. The irradiation power in the wavelength range from 300 nm to 800 nm is 765 W/m.sup.2 V. A UV cut-off filter having an edge wavelength of 310 nm is used in order to simulate the so-called window glass mode. In each series of experiments, at least four test cells are investigated for each condition, and the respective results are indicated as averages of the corresponding individual measurements.

[0423] The decrease in the voltage holding ratio (VHR) usually caused by the exposure, for example by UV irradiation or by LCD backlighting, is determined in accordance with the following equation (1):

[00001]$\begin{array}{cc}\mathrm{VHR}\left(t\right)=\mathrm{VHR}\left(t\right)-\mathrm{VHR}\left(t=0\right).& \left(1\right)\end{array}$

[0424] In order to investigate the low-temperature stability, also known as LTS, i.e. the stability of the LC mixture in the bulk against spontaneous crystallisation of individual components at low temperatures or the occurrence of smectic phases, as the case may be, several sealed bottles, each containing about 1 g of the material, are stored at one or more given temperatures, typically of 10 C., 20 C., 30 C. and/or 40 C. and it is inspected at regular intervals visually, whether a phase transition is observed or not.

[0425] As soon as the first one of the samples at a given temperature shows a change the test is discontinued and the time until the last inspection, at which no change has been observed, is noted as the respective LTS. The test is run for 1000 h. If after 1000 h no change has occurred, the result is LTS>1000 h The ion density from which the resistivity is calculated is measured using the commercially available LC Material Characteristics Measurement System Model 6254 from Toyo Corporation, Japan, using VHR test cells with AL16301 Polyimide (JSR Corp., Japan) having a 3.2 m cell gap. The measurement is performed after 5 min of storage in an oven at 60 C. or 100 C.

[0426] The so-called HTP denotes the helical twisting power of an optically active or chiral substance in an LC medium (in m). Unless indicated otherwise, the HTP is measured in the commercially available nematic LC host mixture MLD-6260 (Merck KGaA) at a temperature of 20 C.

[0427] The Clearing point is measured using the Mettler Thermosystem FP900. The optical anisotropy (n) is measured using an Abbe-Refraktometer H.sub.005 (Natrium-spectral lamp Na10 at 589 nm, 20 C.). The dielectric anisotropy () is measured using an LCR-Meter E4980A/Agilent (G005) at 20 C. (-parallel-cells with JALS 2096-R.sup.1). The turn on voltage (V.sub.0) is measured using an LCR-Meter E4980A/Agilent (G005) at 20 C. (-parallel-cells with JALS 2096-R.sup.1). The rotational viscosity (.sub.1) is measured using a TOYO LCM-2 (0002) at 20 C. (gamma 1 negative cells with JALS-2096-R1). The elastic constant (K.sub.1, splay) is measured using an LCR-Meter E4980A/Agilent (G005) at 20 C. (s parallel-cells with JALS 2096-R.sup.1). K.sub.3: The elastic constant (K.sub.3, bend) is measured using an LCR-Meter E4980A/Agilent (G005) at 20 C. (-parallel-cells with JALS 2096-R1).

[0428] Unless explicitly noted otherwise, all concentrations in the present application are indicated in percent by weight and relate to the corresponding mixture as a whole, comprising all solid or liquid-crystalline components, without solvents. All physical properties are determined in accordance with Merck Liquid Crystals, Physical Properties of Liquid Crystals, Status November 1997, Merck KGaA, Germany, and apply for a temperature of 20 C., unless explicitly indicated otherwise.

[0429] The following mixture examples having positive dielectric anisotropy are suitable, in particular, for liquid-crystal displays which have at least one planar alignment layer, such as, for example, IPS and FFS displays, in particular UBFFS(=ultra-bright FFS), and for VA displays.

EXAMPLES

[0430] The composition and physical properties of comparative Mixture C-1 and the nematic mixtures M-1 to M-12 are given in the following tables. The composition is given in percent by weight.

Comparative Example C1

TABLE-US-00008 APUQU-3-F 3.0 cl. p. [ C.]: 104.5 CC-3-2V1 2.0 n [589 nm, 20 C.]: 0.0920 CC-3-V 37.75 [1 kHz, 20 C.]: 3.1 CC-3-V1 6.0 .sub.1 [mPa s, 20 C.]: 89 CCP-V-1 5.0 K.sub.1 [pN, 20 C.]: 17.9 CCP-V2-1 12.0 K.sub.3 [pN, 20 C.]: 21.1 CCPC-33 3.0 CCVC-3-V 1.75 CDUQU-3-F 8.0 CLP-V-1 8.0 CLY-3-O2 5.0 DGUQU-4-F 1.5 LB(S)-3-OT 2.0 CP-3-O2 1.0 PP-1-2V1 4.0 100.0

Mixture Example M1

TABLE-US-00009 APUQU-3-F 3.0 cl. p. [ C.]: 104.3 CC-3-2V1 2.0 n [589 nm, 20 C.]: 0.0925 CC-3-V 37.75 [1 kHz, 20 C.]: 3.2 CC-3-V1 6.0 .sub.1 [mPa s, 20 C.]: 87 CCP-V-1 5.0 K.sub.1 [pN, 20 C.]: 18.2 CCP-V2-1 12.0 K.sub.3 [pN, 20 C.]: 20.7 CCVC-3-V 1.75 LTS bulk [h, 40 C.]: 1000 CDUQU-3-F 8.0 CLP-V-1 8.0 CLPC-3-2 3.0 CLY-3-O2 5.0 DGUQU-4-F 1.5 LB(S)-3-OT 2.0 CP-3-O2 1.0 PP-1-2V1 4.0 100.0

[0431] In the following table, key parameters of the mixtures C1 and M1 are summarized.

TABLE-US-00010 n K.sub.av [pN] .sub.1 [mPas] .sub.1/K.sub.1 [mPas/pN] C1 3.1 0.0920 16.0 89 5.0 M1 3.2 0.0925 16.0 87 4.8

[0432] It is surprisingly found that the replacement of the compounds CCPC-3-3 of Comparative Mixture C1 with the compound CLPC-2-3 of the formula I in Mixture Example 1, a favorably lower rotational viscosity (.sub.1) and at the same time a lower ratio .sub.1/K.sub.1 can be achieved, which improves the response time of a display.

Mixture Example M2

TABLE-US-00011 CC-3-V 34.0 cl. p. [ C.]: 107 CC-3-V1 6.5 n [589 nm, 20 C.]: 0.1215 CCP-V-1 15.0 [1 kHz, 20 C.]: 3.8 CCP-V2-1 4.0 .sub.1 [mPa s, 20 C.]: 84 CCVC-3-V 3.0 K.sub.1 [pN, 20 C.]: 17.7 CDUQU-3-F 3.7 K.sub.3 [pN, 20 C.]: 18.5 CLP-V-1 4.5 CLPC-3-2 3.0 CPGP-4-3 1.0 DGUQU-4-F 4.0 PGP-2-2V 5.0 PGUQU-3-F 4.3 PP-1-2V1 1.5 PPGU-3-F 0.5 PUS-3-2 10.0 100.0

Mixture Example M3

TABLE-US-00012 CGPC-5-3 1.0 cl. p. [ C.]: 119.6 CC-3-V 27.75 n [589 nm, 20 C.]: 0.1302 CC-3-V1 6.25 [1 kHz, 20 C.]: 4.2 CCP-V-1 15.0 .sub.1 [mPa s, 20 C.]: 103 CCP-V2-1 10.0 K.sub.1 [pN, 20 C.]: 19.1 CCVC-3-V 4.25 K.sub.3 [pN, 20 C.]: 19.6 CDUQU-3-F 2.25 LTS bulk [h, 40 C.]: 1000 CLPC-3-2 3.0 CPGP-4-3 2.5 DGUQU-4-F 4.0 CP-3-O2 0.5 PGP-2-2V 4.0 PGUQU-3-F 4.5 PGUQU-4-F 2.0 PPGU-3-F 0.5 PUS-3-2 12.5 100.0

Mixture Example M4

TABLE-US-00013 CC-3-V 33.0 cl. p. [ C.]: 103.8 CC-3-V1 6.0 n [589 nm, 20 C.]: 0.1140 CC-4-V1 4.0 [1 kHz, 20 C.]: 4.0 CCGU-3-F 0.75 .sub.1 [mPa s, 20 C.]: 87 CCP-V-1 13.5 K.sub.1 [pN, 20 C.]: 17.4 CCP-V2-1 4.0 K.sub.3 [pN, 20 C.]: 18.6 CDUQU-3-F 3.0 CLP-V-1 5.0 CLPC-3-2 4.0 DGUQU-4-F 2.75 LB(S)-3-OT 5.0 CP-3-O2 1.0 PGP-2-2V 7.5 PGUQU-3-F 4.0 PGUQU-4-F 3.0 PP-1-2V1 3.0 PPGU-3-F 0.5 100.0

Mixture Example M5

TABLE-US-00014 APUQU-3-F 3.0 cl. p. [ C.]: 104.5 CC-3-2V1 2.0 n [589 nm, 20 C.]: 0.0924 CC-3-V 37.75 [1 kHz, 20 C.]: 3.2 CC-3-V1 6.0 .sub.1 [mPa s, 20 C.]: 86 CCP-V-1 5.0 K.sub.1 [pN, 20 C.]: 18.0 CCP-V2-1 12.0 K.sub.3 [pN, 20 C.]: 20.2 CCC-3-V 1.75 CDUQU-3-F 8.0 CLP-V-1 8.0 CLPC-3-2 3.0 CLY-3-O2 5.0 DGUQU-4-F 1.5 LB(S)-3-OT 2.0 CP-3-O2 1.0 PP-1-2V1 4.0 100.0

Mixture Example M6

TABLE-US-00015 APUQU-3-F 3.0 cl. p. [ C.]: 101 CC-3-2V1 3.5 n [589 nm, 20 C.]: 0.0899 CC-3-V 37.75 [1 kHz, 20 C.]: 3.2 CC-3-V1 6.0 .sub.1 [mPa s, 20 C.]: 84 CCP-V-1 5.0 K.sub.1 [pN, 20 C.]: 17.8 CCP-V2-1 13.0 K.sub.3 [pN, 20 C.]: 20.5 CCVC-3-V 1.75 CDUQU-3-F 8.0 CLP-V-1 8.0 CLPC-3-2 3.0 CLOY-3-O2 2.5 DGUQU-4-F 1.5 LB(S)-3-OT 2.0 CP-3-O2 1.0 PP-1-2V1 4.0 100.0

Mixture M7

[0433] Mixture M28 consists of 99.975% of Mixture M1 and 250 ppm of the stabiliser ST-3c

##STR00599##

Mixture M8

[0434] Mixture M29 consists of 99.975% of Mixture M2, 150 ppm of Stabiliser ST-3d and 100 ppm of stabiliser ST-19a

##STR00600##

Mixture Example M9

TABLE-US-00016 CGPC-5-3 1.0 cl. p. [ C.]: 119 CC-3-V 27.75 n [589 nm, 20 C.]: 0.1288 CC-3-V1 6.25 [1 kHz, 20 C.]: 4.2 CCP-V-1 15.0 .sub.1 [mPa s, 20 C.]: 106 CCP-V2-1 10.0 K.sub.1 [pN, 20 C.]: 19.0 CCVC-3-V 4.25 K.sub.3 [pN, 20 C.]: 20.0 CDUQU-3-F 2.25 LTS bulk [h, 40 C.]: 1000 CLPC-3-2 3.0 CPGP-4-3 2.5 DGUQU-4-F 4.0 CP-3-O2 0.5 PGP-2-2V 4.0 PGIGI-3-F 2.5 PGUQU-3-F 4.5 PGUQU-4-F 2.0 PPGU-3-F 0.5 PUS-3-2 10.0 100.0

Mixture Example M10

TABLE-US-00017 CC-3-V 33.0 cl. p. [ C.]: 101 CC-3-V1 6.0 n [589 nm, 20 C.]: 0.1125 CC-4-V1 4.0 [1 kHz, 20 C.]: 3.9 CCGU-3-F 0.75 .sub.1 [mPa s, 20 C.]: 84 CCP-V-1 13.5 CCP-V2-1 4.0 CDUQU-3-F 3.0 CLP-V-1 5.0 CLPC-3-2 4.0 DGUQU-4-F 2.75 LB(S)-3-OT 3.0 B(S)-5-F 2.0 CP-3-O2 1.0 PGP-2-2V 7.5 PGUQU-3-F 4.0 PGUQU-4-F 3.0 PP-1-2V1 3.0 PPGU-3-F 0.5 100.0

Mixture Example M11

TABLE-US-00018 APUQU-3-F 3.5 cl. p. [ C.]: 104 CC-3-2V1 2.0 n [589 nm, 20 C.]: 0.0920 CC-3-V 37.75 [1 kHz, 20 C.]: 3.2 CC-3-V1 6.0 .sub.1 [mPa s, 20 C.]: 85 CCP-V-1 6.0 CCP-V2-1 12.0 CCVC-3-V 1.75 CDUQU-3-F 8.0 CLP-V-1 8.0 CLPC-3-2 3.0 CLY-3-O2 4.0 DGUQU-4-F 1.5 B(P)-4O-O4 1.5 CP-3-O2 1.0 PP-1-2V1 4.0 100.0

Mixture Example M12

TABLE-US-00019 APUQU-3-F 3.0 cl. p. [ C.]: 103 CC-3-2V1 2.0 n [589 nm, 20 C.]: 0.0922 CC-3-V 37.75 [1 kHz, 20 C.]: 3.1 CC-3-V1 6.0 .sub.1 [mPa s, 20 C.]: 86 CCP-V-1 6.0 K.sub.1 [pN, 20 C.]: 18.1 CCP-V2-1 12.0 K.sub.3 [pN, 20 C.]: 20.5 CCVC-3-V 1.75 CDUQU-3-F 8.0 CLP-V-1 8.0 CLPC-3-2 3.0 CLY-3-O2 4.0 DGUQU-4-F 1.5 B(S)-2O-O5 2.0 CP-3-O2 1.0 PP-1-2V1 4.0 100.0