POLYMERISABLE COMPOUNDS AND THE USE THEREOF IN LIQUID-CRYSTAL DISPLAYS

Abstract

The present invention relates to polymerisable compounds, to processes and intermediates for the preparation thereof, to liquid-crystal (LC) media comprising them, and to the use of the polymerisable compounds and LC media for optical, electro-optical and electronic purposes, in particular in LC displays, especially in LC displays of the polymer sustained alignment type.

Claims

1. A liquid-crystal medium comprising one or more compounds of formula I
P-Sp-(A.sup.2-Z.sup.2-A.sup.1).sub.m1-Z.sup.1-T I wherein the individual radicals, independently of each other, and on each occurrence identically or differently, have the following meanings T a group selected from the following formulae ##STR00336## R.sup.a-f straight chain or branched alkyl with 1 to 10 C atoms, R.sup.g H or straight chain or branched alkyl with 1 to 10 C atoms, or benzyl, P vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane or epoxy, Sp a spacer group or a single bond, A.sup.1, A.sup.2 an alicyclic, heterocyclic, aromatic or heteroaromatic group with 4 to 30 ring atoms, which may also contain fused rings, and is optionally substituted by one or more groups L or R-(A.sup.3-Z.sup.3).sub.m2-, and one of A.sup.1 and A.sup.2 may also denote a single bond, A.sup.3 an alicyclic, heterocyclic, aromatic or heteroaromatic group with 4 to 30 ring atoms, which may also contain fused rings, and is optionally substituted by one or more groups L, Z.sup.1 —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —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.n—, —CF.sub.2CH.sub.2—, —CH.sub.2CF.sub.2—, —(CF.sub.2).sub.n—, —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH—, —CH.sub.2—CH.sub.2—CO—O—, —O—CO—CH.sub.2—CH.sub.2—, —CR.sup.00R.sup.000—, or a single bond, with the proviso that, if m1 is 0 and Sp is a single bond, Z.sup.1 is a single bond, Z.sup.2, Z.sup.3 —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —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.n—, —CF.sub.2CH.sub.2—, —CH.sub.2CF.sub.2—, —(CF.sub.2).sub.n—, —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH—, —CH.sub.2—CH.sub.2—CO—O—, —O—CO—CH.sub.2—CH.sub.2—, —CR.sup.00R.sup.000—, or a single bond, R.sup.00, R.sup.000 H or alkyl having 1 to 12 C atoms, R P-Sp-, H, F, Cl, CN, or straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH.sub.2-groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F, Cl or P-Sp-, or R is a group selected from formula 1, 2, 3 and 4, L P-Sp-, F, Cl, CN, or straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH.sub.2-groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F, Cl or P-Sp-, or L is a group selected from formula 1, 2, 3 and 4, m1 0, 1, 2, 3 or 4, m2 0, 1, 2, 3 or 4, n 1, 2, 3 or 4.

2. The LC medium of claim 1, characterized in that R.sup.a-d are selected, independently of each other, from methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl.

3. The LC medium of claim 1, characterized in that -(A.sup.2-Z.sup.2-A.sup.1).sub.m1- denotes benzene, biphenylene, p-terphenylene (1,4-diphenylbenzene), m-terphenylene (1,3-diphenylbenzene), naphthylene, 2-phenyl-naphthylene, phenanthrene or anthracene, all of which are optionally substituted by one or more groups L.

4. The LC medium according to claim 1, characterized in that -(A.sup.2-Z.sup.2-A.sup.1).sub.m1- is a single bond or is selected from the following formulae ##STR00337## ##STR00338## wherein L is as defined for the compound of formula I, r is 0, 1, 2, 3 or 4, s is 0, 1, 2 or 3, t is 0, 1 or 2, and u is 0, 1, 2, 3, 4 or 5.

5. The LC medium according to claim 1, characterized in that the compounds of formula I are selected from the following subformulae ##STR00339## ##STR00340## ##STR00341## ##STR00342## ##STR00343## ##STR00344## ##STR00345## ##STR00346## ##STR00347## ##STR00348## wherein P, Sp, R.sup.a-d, Z.sup.1, L and R are as defined for the compound of formula I, r is 0, 1, 2, 3 or 4 and s is 0, 1, 2 or 3.

6. The LC medium according to claim 1, characterized in that Z.sup.1, Z.sup.2 and Z.sup.3 denote —CO—O—, —O—CO— or a single bond.

7. The LC medium according to claim 1, characterized in that P is acrylate or methacrylate.

8. The LC medium according to claim 1, characterized in that Sp is a single bond.

9. The LC medium according to claim 1, characterized in that it additionally comprises one or more polymerisable compounds that are different from formula I.

10. The LC medium of claim 9, characterized in that it comprises a polymerisable component A) comprising one or more polymerisable compounds of formula I, and optionally one or more polymerisable compounds different from formula I, a liquid-crystalline LC component B) comprising one or more mesogenic or liquid-crystalline compounds.

11. The LC medium according to claim 9, characterized in that the said polymerisable compounds that are different from formula I are selected from the following formulae ##STR00349## ##STR00350## ##STR00351## ##STR00352## ##STR00353## in which the individual radicals have the following meanings: P.sup.1, P.sup.2, P.sup.3 each, independently of one another, denote an acrylate or methacrylate group, Sp.sup.1, Sp.sup.2, Sp.sup.3 each, independently of one another, denote a single bond or a spacer group, R.sup.aa denotes 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)—, —C≡C—, —N(R.sup.0)—, —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— 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.1-Sp.sup.1-, R.sup.0, R.sup.00 each, independently of one another and identically or differently on each occurrence, denote H or alkyl having 1 to 12 C atoms, R.sup.y and R.sup.z each, independently of one another, denote H, F, CH.sub.3 or CF.sub.3, X.sup.1, X.sup.2 and X.sup.3 each, independently of one another, denote —CO—O—, —O—CO— or a single bond, Z.sup.1 denotes —O—, —CO—, —C(R.sup.yR.sup.z)— or —CF.sub.2CF.sub.2—, Z.sup.2 and Z.sup.3 each, independently of one another, denote —CO—O—, —O—CO—, —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, L on each occurrence, identically or differently, denotes F, Cl, CN or straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms, preferably F, L′ and L″ each, independently of one another, denote H, F or Cl, r denotes 0, 1, 2, 3 or 4, s denotes 0, 1, 2 or 3, t denotes 0, 1 or 2, x denotes 0 or 1.

12. The LC medium according to claim 11, characterized in that the polymerisable compounds that are different from formula I are selected from formula M2.

13. The LC medium according to claim 1, characterized in that it comprises one or more compounds selected from the formulae CY and PY: ##STR00354## in which the individual radicals have the following meanings: a denotes 1 or 2, b denotes 0 or 1, ##STR00355## R.sup.1 and R.sup.2 each, independently of one another, denote alkyl having 1 to 12 C atoms, where, in addition, one or two non-adjacent CH.sub.2 groups may be replaced by —O—, —CH═CH—, —CO—, —O—CO— or —CO—O— in such a way that O atoms are not linked directly to one another, Z.sup.x denotes —CH═CH—, —CH.sub.2O—, —OCH.sub.2—, —CF.sub.2O—, —OCF.sub.2—, —O—, —CH.sub.2—, —CH.sub.2CH.sub.2— or a single bond, L.sup.1-4 each, independently of one another, denote F, Cl, OCF.sub.3, CF.sub.3, CH.sub.3, CH.sub.2F, CHF.sub.2.

14. The LC medium according to claim 1, characterized in that it comprises one or more compounds selected from the following formulae: ##STR00356## in which the individual radicals, on each occurrence identically or differently, each, independently of one another, have the following meaning: ##STR00357## R.sup.A1 alkenyl having 2 to 9 C atoms or, if at least one of the rings X, Y and Z denotes cyclohexenyl, also one of the meanings of R.sup.A2, R.sup.A2 alkyl having 1 to 12 C atoms, in which, in addition, one or two non-adjacent CH.sub.2 groups may be replaced by —O—, —CH═CH—, —CO—, —CO— or —COO— in such a way that O atoms are not linked directly to one another, Z.sup.x —CH.sub.2CH.sub.2—, —CH═CH—, —CF.sub.2O—, —OCF.sub.2—, —CH.sub.2O—, —OCH.sub.2—, —CO—O—, —O—CO—, —C.sub.2F.sub.4—, —CF═CF—, —CH═CH—CH.sub.2O—, or a single bond, L.sup.1-4 each, independently of one another, H, F, Cl, OCF.sub.3, CF.sub.3, CH.sub.3, CH.sub.2F or CHF.sub.2H, x 1 or 2, z 0 or 1.

15. The LC medium according to claim 1, characterized in that it comprises one or more compounds of the following formula: ##STR00358## in which the individual radicals have the following meanings: ##STR00359## R.sup.3 and R.sup.4 each, independently of one another, denote alkyl having 1 to 12 C atoms, in which, in addition, one or two non—adjacent CH.sub.2 groups may be replaced by —O—, —CH═CH—, —CO—, —O—CO— or —CO—O— in such a way that O atoms are not linked directly to one another, Z.sup.y denotes —CH.sub.2CH.sub.2—, —CH═CH—, —CF.sub.2O—, —OCF.sub.2—, —CH.sub.2O—, —OCH.sub.2—, —COO—, —OCO—, —C.sub.2F.sub.4—, —CF═CF— or a single bond.

16. The LC medium according to claim 1, characterized in that the polymerisable compounds are polymerised.

17. A process of preparing an LC medium of claim 1, comprising the steps of mixing one or more mesogenic or liquid-crystalline compounds, or a liquid-crystalline component B) comprising one or more mesogenic or liquid-crystalline compounds, with one or more compounds of formula I, optionally with one or more polymerisable compounds that are different from formula I, and optionally with further liquid-crystalline compounds and/or additives.

18. An LC display comprising one or more compounds of formula I, which is as defined as in claim 1,
P-Sp-(A.sup.2-Z.sup.2-A.sup.1).sub.m1-Z.sup.1-T I wherein the individual radicals, independently of each other, and on each occurrence identically or differently, have the following meanings T a group selected from the following formulae ##STR00360## R.sup.a-f straight chain or branched alkyl with 1 to 10 C atoms, R.sup.g H or straight chain or branched alkyl with 1 to 10 C atoms, or benzyl, P vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane or epoxy, Sp a spacer group or a single bond, A.sup.1, A.sup.2 an alicyclic, heterocyclic, aromatic or heteroaromatic group with 4 to 30 ring atoms, which may also contain fused rings, and is optionally substituted by one or more groups L or R-(A.sup.3-Z.sup.3).sub.m2-, and one of A.sup.1 and A.sup.2 may also denote a single bond, A.sup.3 an alicyclic, heterocyclic, aromatic or heteroaromatic group with 4 to 30 ring atoms, which may also contain fused rings, and is optionally substituted by one or more groups L, Z.sup.1 —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —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.n,—CF.sub.2CH.sub.2—, —CH.sub.2CF.sub.2—, —(CF.sub.2).sub.n—, —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH—, —CH.sub.2—CH.sub.2—CO—O—, —O—CO—CH.sub.2—CH.sub.2—, —CR.sup.00 R.sup.000—, or a single bond, with the proviso that, if m1 is 0 and Sp is a single bond, Z.sup.1 is a single bond, Z.sup.2, Z.sup.3 —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —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.n—, —CF.sub.2CH.sub.2—, —CH.sub.2CF.sub.2—, —(CF.sub.2).sub.n—, —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH—, —CH.sub.2—CH.sub.2—CO—O—, —O—CO—CH.sub.2—CH.sub.2—, —CR.sup.00R.sup.000—, or a single bond, R.sup.00, R.sup.000 H or alkyl having 1 to 12 C atoms, R P-Sp-, H, F, Cl, CN, or straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH.sub.2-groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F, Cl or P-Sp-, or R is a group selected from formula 1, 2, 3 and 4, L P-Sp-, F, Cl, CN, or straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH.sub.2-groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F, Cl or P-Sp-, or L is a group selected from formula 1, 2, 3 and 4, m1 0, 1, 2, 3 or 4, m2 0, 1, 2, 3 or 4, n 1, 2, 3 or 4.

19. The LC display of claim 18, which is a PSA type display.

20. The LC display of claim 18, which is a PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS, PS-posi-VA or PS-TN display.

21. The LC display of claim 20, characterized in that it comprises two substrates, at least one which is transparent to light, an electrode provided on each substrate or two electrodes provided on only one of the substrates, and located between the substrates a layer of an LC medium, comprising one or more polymerisable compounds of formula I, wherein the polymerisable compounds are polymerised between the substrates of the display.

22. A process for the production of an LC display according to claim 21, comprising the steps of providing an LC medium, comprising one or more polymerisable compounds of formula I, between the substrates of the display, and polymerising the polymerisable compounds.

23. A compound of formula I
P-Sp-(A.sup.2-Z.sup.2-A.sup.1).sub.m1-Z.sup.1-T I wherein the individual radicals, independently of each other, and on each occurrence identically or differently, have the following meanings T a group selected from the following formulae ##STR00361## R.sup.a-f straight chain or branched alkyl with 1 to 10 C atoms, R.sup.g H or straight chain or branched alkyl with 1 to 10 C atoms, or benzyl, P vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane or epoxy, Sp a spacer group or a single bond, A.sup.1, A.sup.2 an alicyclic, heterocyclic, aromatic or heteroaromatic group with 4 to 30 ring atoms, which may also contain fused rings, and is optionally substituted by one or more groups L or R-(A.sup.3-Z.sup.3).sub.m2-, and one of A.sup.1 and A.sup.2 may also denote a single bond, A.sup.3 an alicyclic, heterocyclic, aromatic or heteroaromatic group with 4 to 30 ring atoms, which may also contain fused rings, and is optionally substituted by one or more groups L, Z.sup.1 —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —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.n—, —CF.sub.2CH.sub.2—, —CH.sub.2CF.sub.2—, —(CF.sub.2).sub.n—, —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH—, —CH.sub.2—CH.sub.2—CO—O—, —O—CO—CH.sub.2—CH.sub.2—, —CR.sup.00R.sup.000 —, or a single bond, with the proviso that, if m1 is 0 and Sp is a single bond, Z.sup.1 is a single bond, Z.sup.2, Z.sup.3 —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —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.n—, —CF.sub.2CH.sub.2—, —CH.sub.2CF.sub.2—, —(CF.sub.2).sub.n—, —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH—, —CH.sub.2—CH.sub.2—CO—O—, —O—CO—CH.sub.2—CH.sub.2—, —CR.sup.00R.sup.000—, or a single bond, R.sup.00, R.sup.000 H or alkyl having 1 to 12 C atoms, R P-Sp-, H, F, Cl, CN, or straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH.sub.2-groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F, Cl or P-Sp-, or R is a group selected from formula 1, 2, 3 and 4, L P-Sp-, F, Cl, CN, or straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH.sub.2-groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F, Cl or P-Sp-, or L is a group selected from formula 1, 2, 3 and 4, ##STR00362## m1 1, 2, 3 or 4, m2 0, 1, 2, 3 or 4, n 1, 2, 3 or 4.

24. A compound of formula II
Pg-Sp-(A.sup.2-Z.sup.2-A.sup.1).sub.m1-Z.sup.1-T II wherein T a group selected from the following formulae ##STR00363## R.sup.a-f straight chain or branched alkyl with 1 to 10 C atoms, R.sup.g H or straight chain or branched alkyl with 1 to 10 C atoms, or benzyl, Sp a spacer group or a single bond, A.sup.1, A.sup.2 an alicyclic, heterocyclic, aromatic or heteroaromatic group with 4 to 30 ring atoms, which may also contain fused rings, and is optionally substituted by one or more groups L or R-(A.sup.3-Z.sup.3).sub.m2-, and one of A.sup.1 and A.sup.2 may also denote a single bond, A.sup.3 an alicyclic, heterocyclic, aromatic or heteroaromatic group with 4 to 30 ring atoms, which may also contain fused rings, and is optionally substituted by one or more groups L, Z.sup.1 —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —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.n—, —CF.sub.2CH.sub.2—, —CH.sub.2CF.sub.2—, —(CF.sub.2).sub.n—, —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH—, —CH.sub.2—CH.sub.2—CO—O—, —O—CO—CH.sub.2—CH.sub.2—, —CR.sup.00R.sup.000—, or a single bond, with the proviso that, if m1 is 0 and Sp is a single bond, Z.sup.1 is a single bond, Z.sup.2, Z.sup.3 —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —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.n—, CF.sub.2CH.sub.2—, —CH.sub.2CF.sub.2—, —(CF.sub.2).sub.n—, —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH—, —CH.sub.2—CH.sub.2—CO—O—, —O—CO—CH.sub.2—CH.sub.2—, —CR.sup.00R.sup.000—, or a single bond, R.sup.00, R.sup.000 H or alkyl having 1 to 12 C atoms, R Pg-Sp-, H, F, Cl, CN, or straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH.sub.2-groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F, Cl or Pg-Sp-, or R is a group selected from formula 1, 2, 3 and 4, L Pg-Sp-, F, Cl, CN, or straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH.sub.2-groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F, Cl or Pg-Sp-, or L is a group selected from formula 1, 2, 3 and 4, m1 0, 1, 2, 3 or 4, m2 0, 1, 2, 3 or 4, n 1, 2, 3 or 4, and Pg denotes OH, a protected hydroxyl group or a masked hydroxyl group.

25. A process for preparing a compound of formula I
P-Sp-(A.sup.2-Z.sup.2-A.sup.1).sub.m1-Z.sup.1-T I wherein the individual radicals, independently of each other, and on each occurrence identically or differently, have the following meanings T a group selected from the following formulae ##STR00364## R.sup.a-f straight chain or branched alkyl with 1 to 10 C atoms, R.sup.g H or straight chain or branched alkyl with 1 to 10 C atoms, or benzyl, P vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane or epoxy, Sp a spacer group or a single bond, A.sup.1, A.sup.2 an alicyclic, heterocyclic, aromatic or heteroaromatic group with 4 to 30 ring atoms, which may also contain fused rings, and is optionally substituted by one or more groups L or R-(A.sup.3-Z.sup.3).sub.m2-, and one of A.sup.1 and A.sup.2 may also denote a single bond, A.sup.3 an alicyclic, heterocyclic, aromatic or heteroaromatic group with 4 to 30 ring atoms, which may also contain fused rings, and is optionally substituted by one or more groups L, Z.sup.1 —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —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.n—, —CF.sub.2CH.sub.2—, —CH.sub.2CF.sub.2—, —(CF.sub.2).sub.n—, —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH—, —CH.sub.2—CH.sub.2—CO—O—, —O—CO—CH.sub.2—CH.sub.2—, —CR.sup.00R.sup.000—, or a single bond, with the proviso that, if m1 is 0 and Sp is a single bond, Z.sup.1 is a single bond, Z.sup.2, Z.sup.3 —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —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.n—, —CF.sub.2CH.sub.2—, —CH.sub.2CF.sub.2—, —(CF.sub.2).sub.n—, —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH—, —CH.sub.2—CH.sub.2—CO—O—, —O—CO—CH.sub.2—CH.sub.2—, —CR.sup.00R.sup.000—, or a single bond, R.sup.00, R.sup.000 H or alkyl having 1 to 12 C atoms, R P-Sp-, H, F, Cl, CN, or straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH.sub.2-groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F, Cl or P-Sp-, or R is a group selected from formula 1, 2, 3 and 4, L P-Sp-, F, Cl, CN, or straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH.sub.2-groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F, Cl or P-Sp-, or L is a group selected from formula 1, 2, 3 and 4, m1 0, 1, 2, 3 or 4, m2 0, 1, 2, 3 or 4, n 1, 2, 3 or 4, wherein P preferably denotes acrylate or methacrylate, by esterification of a compound of claim 24, wherein Pg denotes OH, using corresponding acids, acid derivatives, or halogenated compounds containing a group P, in the presence of a dehydrating reagent.

26. An LC display comprising an LC medium according to claim 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0079] Unless stated otherwise, the compounds of formula I are preferably selected from achiral compounds.

[0080] As used herein, the terms “active layer” and “switchable layer” mean a layer in an electrooptical display, for example an LC display, that comprises one or more molecules having structural and optical anisotropy, like for example LC molecules, which change their orientation upon an external stimulus like an electric or magnetic field, resulting in a change of the transmission of the layer for polarized or unpolarized light.

[0081] As used herein, the terms “tilt” and “tilt angle” will be understood to mean a tilted alignment of the LC molecules of an LC medium relative to the surfaces of the cell in an LC display (here preferably a PSA display). The tilt angle here denotes the average angle (<90°) between the longitudinal molecular axes of the LC molecules (LC director) and the surface of the plane-parallel outer plates which form the LC cell. A low value for the tilt angle (i.e. a large deviation from the 90° angle) corresponds to a large tilt here. A suitable method for measurement of the tilt angle is given in the examples. Unless indicated otherwise, tilt angle values disclosed above and below relate to this measurement method.

[0082] As used herein, the terms “reactive mesogen” and “RM” will be understood to mean a compound containing a mesogenic or liquid-crystalline skeleton, and one or more functional groups attached thereto which are suitable for polymerisation and are also referred to as “polymerisable group” or “P”.

[0083] Unless stated otherwise, the term “polymerisable compound” as used herein will be understood to mean a polymerisable monomeric compound.

[0084] As used herein, the term “low-molecular-weight compound” will be understood to mean to a compound that is monomeric and/or is not prepared by a polymerisation reaction, as opposed to a “polymeric compound” or a “polymer”.

[0085] As used herein, the term “unpolymerisable compound” will be understood to mean a compound that does not contain a functional group that is suitable for polymerisation under the conditions usually applied for the polymerisation of the RMs.

[0086] The term “mesogenic group” as used herein is known to the person skilled in the art and described in the literature, and means a group which, due to the anisotropy of its attracting and repelling interactions, essentially contributes to causing a liquid-crystal (LC) phase in low-molecular-weight or polymeric substances. Compounds containing mesogenic groups (mesogenic compounds) do not necessarily have to have an LC phase themselves. It is also possible for mesogenic compounds to exhibit LC phase behaviour only after mixing with other compounds and/or after polymerisation. Typical mesogenic groups are, for example, rigid rod- or disc-shaped units. An overview of the terms and definitions used in connection with mesogenic or LC compounds is given in Pure Appl. Chem. 2001, 73(5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368.

[0087] The term “spacer group”, hereinafter also referred to as “Sp”, as used herein is known to the person skilled in the art and is described in the literature, see, for example, Pure Appl. Chem. 2001, 73(5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368. As used herein, the terms “spacer group” or “spacer” mean a flexible group, for example an alkylene group, which connects the mesogenic group and the polymerisable group(s) in a polymerisable mesogenic compound.

[0088] Above and below,

##STR00002##

denotes a trans-1,4-cyclohexylene ring, and

##STR00003##

denotes a 1,4-phenylene ring.

[0089] Above and below “organic group” denotes a carbon or hydrocarbon group.

[0090] “Carbon group” denotes a mono- or polyvalent organic group containing at least one carbon atom, where this either contains no further atoms (such as, for example, —C≡C—) or optionally contains one or more further atoms, such as, for example, N, O, S, B, P, Si, Se, As, Te or Ge (for example carbonyl, etc.). The term “hydrocarbon group” denotes a carbon group which additionally contains one or more H atoms and optionally one or more heteroatoms, such as, for example, N, O, S, B, P, Si, Se, As, Te or Ge.

[0091] “Halogen” denotes F, Cl, Br or I.

[0092] —CO—, —C(═O)— and —C(O)— denote a carbonyl group, i.e.

##STR00004##

[0093] A carbon or hydrocarbon group can be a saturated or unsaturated group. Unsaturated groups are, for example, aryl, alkenyl or alkynyl groups. A carbon or hydrocarbon radical having more than 3 C atoms can be straight-chain, branched and/or cyclic and may also contain spiro links or condensed rings.

[0094] The terms “alkyl”, “aryl”, “heteroaryl”, etc., also encompass polyvalent groups, for example alkylene, arylene, heteroarylene, etc.

[0095] The term “aryl” denotes an aromatic carbon group or a group derived therefrom. The term “heteroaryl” denotes “aryl” as defined above, containing one or more heteroatoms, preferably selected from N, O, S, Se, Te, Si and Ge.

[0096] Preferred carbon and hydrocarbon groups are optionally substituted, straight-chain, branched or cyclic, alkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy having 1 to 40, preferably 1 to 20, very preferably 1 to 12, C atoms, optionally substituted aryl or aryloxy having 5 to 30, preferably 6 to 25, C atoms, or optionally substituted alkylaryl, arylalkyl, alkylaryloxy, arylalkyloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy having 5 to 30, preferably 6 to 25, C atoms, wherein one or more C atoms may also be replaced by hetero atoms, preferably selected from N, O, S, Se, Te, Si and Ge.

[0097] Further preferred carbon and hydrocarbon groups are C.sub.1-C.sub.20 alkyl, C.sub.2-C.sub.20 alkenyl, C.sub.2-C.sub.20 alkynyl, C.sub.3-C.sub.20 allyl, C.sub.4-C.sub.20 alkyldienyl, C.sub.4-C.sub.20 polyenyl, C.sub.6-C.sub.20 cycloalkyl, C.sub.4-C.sub.15 cycloalkenyl, C.sub.6-C.sub.30 aryl, C.sub.6-C.sub.30 alkylaryl, C.sub.6.sup.-C.sub.30 arylalkyl, C.sub.6-C.sub.30 alkylaryloxy, C.sub.6-C.sub.30 arylalkyloxy, C.sub.2-C.sub.30 heteroaryl, C.sub.2-C.sub.30 heteroaryloxy.

[0098] Particular preference is given to C.sub.1-C.sub.12 alkyl, C.sub.2-C.sub.12 alkenyl, C.sub.2-C.sub.12 alkynyl, C.sub.6.sup.-C.sub.25 aryl and C.sub.2-C.sub.25 heteroaryl.

[0099] Further preferred carbon and hydrocarbon groups are straight-chain, branched or cyclic alkyl having 1 to 20, preferably 1 to 12, C atoms, which are unsubstituted or mono- or polysubstituted by F, Cl, Br, I or CN and in which one or more non-adjacent CH.sub.2 groups may each be replaced, independently of one another, by —C(R.sup.x)═C(R.sup.x)—, —C≡C—, —N(R.sup.x)—, —O—, —S—, 13 CO—, —CO—O—, —O—CO—, —O—CO—O— in such a way that O and/or S atoms are not linked directly to one another.

[0100] R.sup.x preferably denotes H, F, Cl, CN, a straight-chain, branched or cyclic alkyl chain having 1 to 25 C atoms, in which, in addition, one or more non-adjacent C atoms may be replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— and in which one or more H atoms may be replaced by F or Cl, or denotes an optionally substituted aryl or aryloxy group with 6 to 30 C atoms, or an optionally substituted heteroaryl or heteroaryloxy group with 2 to 30 C atoms.

[0101] Preferred alkyl groups are, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl, s-pentyl, cyclopentyl, n-hexyl, cyclohexyl, 2-ethylhexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, dodecanyl, trifluoromethyl, perfluoro-n-butyl, 2,2,2-trifluoroethyl, perfluorooctyl, perfluorohexyl, etc.

[0102] Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, etc.

[0103] Preferred alkynyl groups are, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, octynyl, etc.

[0104] Preferred alkoxy groups are, for example, methoxy, ethoxy, 2-methoxy-ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy, 2-methylbutoxy, n-pentoxy, n-hexoxy, n-heptoxy, n-octoxy, n-nonoxy, n-decoxy, n-undecoxy, n-dodecoxy, etc.

[0105] Preferred amino groups are, for example, dimethylamino, methylamino, methylphenylamino, phenylamino, etc.

[0106] Aryl and heteroaryl groups can be monocyclic or polycyclic, i.e. they can contain one ring (such as, for example, phenyl) or two or more rings, which may also be fused (such as, for example, naphthyl) or covalently bonded (such as, for example, biphenyl), or contain a combination of fused and linked rings. Heteroaryl groups contain one or more heteroatoms, preferably selected from O, N, S and Se.

[0107] Particular preference is given to mono-, bi- or tricyclic aryl groups having 6 to 25 C atoms and mono-, bi- or tricyclic heteroaryl groups having 5 to 25 ring atoms, which optionally contain fused rings and are optionally substituted. Preference is furthermore given to 5-, 6- or 7-membered aryl and heteroaryl groups, in which, in addition, one or more CH groups may be replaced by N, S or O in such a way that O atoms and/or S atoms are not linked directly to one another.

[0108] Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl, [1,1′:3′,1″]terphenyl-2′-yl, naphthyl, anthracene, binaphthyl, phenanthrene, 9,10-dihydro-phenanthrene, pyrene, dihydropyrene, chrysene, perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene, etc.

[0109] Preferred heteroaryl groups are, for example, 5-membered rings, such as pyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, furan, thiophene, selenophene, oxazole, isoxazole, 1,2-thiazole, 1,3-thiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 6-membered rings, such as pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine, or condensed groups, such as indole, isoindole, indolizine, indazole, benzimidazole, benzotriazole, purine, naphthimidazole, phenanthrimidazole, pyridimidazole, pyrazinimidazole, quinoxalinimidazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, benzothiazole, benzofuran, isobenzofuran, dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, benzoisoquinoline, acridine, phenothiazine, phenoxazine, benzopyridazine, benzopyrimidine, quinoxaline, phenazine, naphthyridine, azacarbazole, benzocarboline, phenanthridine, phenanthroline, thieno[2,3b]thiophene, thieno[3,2b]thiophene, dithienothiophene, isobenzothiophene, dibenzothiophene, benzothiadiazothiophene, or combinations of these groups.

[0110] The aryl and heteroaryl groups mentioned above and below may also be substituted by alkyl, alkoxy, thioalkyl, fluorine, fluoroalkyl or further aryl or heteroaryl groups.

[0111] The (non-aromatic) alicyclic and heterocyclic groups encompass both saturated rings, i.e. those containing exclusively single bonds, and also partially unsaturated rings, i.e. those which may also contain multiple bonds. Heterocyclic rings contain one or more heteroatoms, preferably selected from Si, O, N, S and Se.

[0112] The (non-aromatic) alicyclic and heterocyclic groups can be monocyclic, i.e. contain only one ring (such as, for example, cyclohexane), or polycyclic, i.e. contain a plurality of rings (such as, for example, decahydronaphthalene or bicyclooctane). Particular preference is given to saturated groups. Preference is furthermore given to mono-, bi- or tricyclic groups having 5 to 25 ring atoms, which optionally contain fused rings and are optionally substituted. Preference is furthermore given to 5-, 6-, 7- or 8-membered carbocyclic groups, in which, in addition, one or more C atoms may be replaced by Si and/or one or more CH groups may be replaced by N and/or one or more non-adjacent CH.sub.2 groups may be replaced by —O— and/or —S—.

[0113] Preferred alicyclic and heterocyclic groups are, for example, 5-membered groups, such as cyclopentane, tetrahydrofuran, tetrahydrothiofuran, pyrrolidine, 6-membered groups, such as cyclohexane, silinane, cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1,3-dioxane, 1,3-dithiane, piperidine, 7-membered groups, such as cycloheptane, and fused groups, such as tetrahydronaphthalene, decahydronaphthalene, indane, bicyclo[1.1.1]-pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, octahydro-4,7-methanoindane-2,5-diyl.

[0114] Preferred substituents are, for example, solubility-promoting groups, such as alkyl or alkoxy, electron-withdrawing groups, such as fluorine, nitro or nitrile, or substituents for increasing the glass transition temperature (Tg) in the polymer, in particular bulky groups, such as, for example, t-butyl or optionally substituted aryl groups.

[0115] A preferred substituent for the alicyclic, heterocyclic, aromatic and heteroaromatic groups is L as defined in formula I.

[0116] Preferred substituents L are selected from P-Sp-, F, Cl, —CN, straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy each having 1 to 25 C atoms, in which one or more H atoms may optionally be replaced by F or Cl.

[0117] Very preferred substituents L are, for example, F, Cl, CN, 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.

##STR00005##

is preferably

##STR00006##

in which L has one of the meanings indicated above.

[0118] If the spacer group Sp is different from a single bond, it is preferably selected of the formula Sp″-X″, so that the respective radical P-Sp- conforms to the formula P-Sp″-X″-, wherein [0119] Sp″ denotes alkylene having 1 to 20, preferably 1 to 12, C atoms, which is optionally mono- or polysubstituted by F, Cl, 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—, —CO—O—, —O—CO—, —O—CO—O—, —S—CO—, —CO—S—), —N(R.sup.00)—CO—O—, —O—CO—N(R.sup.0)—, —N(R.sup.0)—CO—N(R.sup.00)—, —CH═CH— or —C≡C— in such a way that O and/or S atoms are not linked directly to one another, [0120] X″ denotes —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —CO—N(R.sup.0)—, —N(R.sup.0)—CO—, —N(R.sup.0)—CO—N(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—, —CH═N—, —N═CH—, —N═N—, —CH═CR.sup.0—, —CY.sup.2═CY.sup.3—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH— or a single bond, [0121] R.sup.0 and R.sup.00 each, independently of one another, denote H or alkyl having 1 to 20 C atoms, and [0122] Y.sup.2 and Y.sup.3 each, independently of one another, denote H, F, Cl or CN.

[0123] X″ is preferably —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR.sup.0—, —NR.sup.0—CO—, —NR.sup.0—CO—NR.sup.00— or a single bond.

[0124] Typical spacer groups Sp and -Sp″-X″- are, for example, —(CH.sub.2).sub.p1—, —(CH.sub.2CH.sub.2O).sub.q1—CH.sub.2CH.sub.2—, —CH.sub.2CH.sub.2—S—CH.sub.2CH.sub.2—, —CH.sub.2CH.sub.2—NH—CH.sub.2CH.sub.2— or —(SiR.sup.0R.sup.00—O).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.

[0125] Particularly preferred groups Sp and -Sp″-X″- are —(CH.sub.2).sub.p1—, —(CH.sub.2).sub.p1—O—, —(CH.sub.2).sub.p1—O—CO—, —(CH.sub.2).sub.p1—CO—O—, —(CH.sub.2).sub.p1—O—CO—O—, in which p1 and q1 have the meanings indicated above.

[0126] 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-methylimino-ethylene, 1-methylalkylene, ethenylene, propenylene and butenylene.

[0127] Preferably R.sup.a-d in formulae 1-3 are selected, independently of each other, from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, very preferably methyl.

[0128] Preferably R.sup.a, R.sup.b, R.sup.c and R.sup.d in formulae 1-3 have the same meaning.

[0129] Preferably R.sup.e and R.sup.f in formula 4 are selected, independently of each other, from methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, very preferably methyl.

[0130] Preferably R.sup.e and R.sup.f in formula 4 have the same meaning.

[0131] In a preferred embodiment of the present invention R.sup.g in formula 2 is H.

[0132] In another preferred embodiment of the present invention R.sup.g in formula 2 is methyl, ethyl, propyl or butyl, very preferably methyl.

[0133] In a preferred embodiment of the present invention R.sup.g in formula 3 is H.

[0134] In another preferred embodiment of the present invention R.sup.g in formula 3 is methyl, ethyl, propyl or butyl, very preferably methyl.

[0135] Preferably m1 in formula I is 1, 2 or 3.

[0136] In another preferred embodiment of the present invention m1 in formula I is 0.

[0137] Preferably Z.sup.1 in formula I denotes —CO—O—, —O—CO— or a single bond, very preferably —CO—O—.

[0138] Preferably Z.sup.2 and Z.sup.3 in formula I denote —CO—O—, —O—CO— or a single bond, very preferably a single bond.

[0139] Preferably P in formula I is an acrylate or methacrylate group.

[0140] Preferably Sp in formula I is a single bond.

[0141] Preferably A.sup.3 in formula I denotes an aromatic or heteroaromatic group with 6 to 24 ring atoms, which may also contain fused rings, and is optionally substituted by one or more groups L.

[0142] Very preferably A.sup.3 in formula I denotes benzene or naphthalene, which is optionally substituted by one or more groups L.

[0143] Preferably A.sup.1 and A.sup.2 in formula I denote an aromatic or heteroaromatic group with 6 to 24 ring atoms, which may also contain fused rings, and is optionally substituted by one or more groups L or R-(A.sup.3-Z.sup.3).sub.m2-, or A.sup.1 is a singe bond.

[0144] Very preferably A.sup.1 and A.sup.2 in formula I denote benzene, naphthalene, phenanthrene or anthracene, which is optionally substituted by one or more groups L or R-(A.sup.3-Z.sup.3).sub.m2-, or A.sup.1 is a singe bond.

[0145] Preferably -(A.sup.2-Z.sup.2-A.sup.1).sub.m1- in formula I denotes benzene, biphenylene, p-terphenylene (1,4-diphenylbenzene), m-terphenylene (1,3-diphenylbenzene), naphthylene, 2-phenyl-naphthylene, phenanthrene or anthracene, all of which are optionally substituted by one or more groups L.

[0146] Very preferably -(A.sup.2-Z.sup.2-A.sup.1).sub.m1- denotes biphenylene, p-terphenylene or m-terphenylene, all of which are optionally substituted by one or more groups L.

[0147] Preferred groups -(A.sup.2-Z.sup.2-A.sup.1).sub.m1- are selected from the following formulae

##STR00007## ##STR00008##

wherein L is as defined in formula I or has one of the preferred meanings as described above and below, r is 0, 1, 2, 3 or 4, s is 0, 1, 2 or 3, t is 0, 1 or 2, and u is 0, 1, 2, 3, 4 or 5.

[0148] Particular preference is given to the groups of formula A1, A2, A3, A4 and A5.

[0149] In another preferred embodiment -(A.sup.2-Z.sup.2-A.sup.1).sub.m1- is a single bond.

[0150] Preferred compounds of formula I are selected from the following subformulae

##STR00009## ##STR00010## ##STR00011## ##STR00012## ##STR00013## ##STR00014## ##STR00015## ##STR00016## ##STR00017##

wherein P, Sp, R.sup.a-d, Z.sup.1, L and R are as defined in formula I or have one of the preferred meanings as described above and below, r is 0, 1, 2, 3 or 4 and s is 0, 1, 2 or 3.

[0151] Preferably Z.sup.1 in formulae I and I1 to I4-11 is —CO—O—, —O—CO—, or a single bond, very preferably —CO—O—.

[0152] Preferably P in formulae I and I1-11 to I4-11 is acrylate or methacrylate.

[0153] Preferably Sp in formulae I and I1-11 to I4-11 is a single bond.

[0154] Preferably R.sup.a, R.sup.b, R.sup.c and R.sup.d in formulae I and I1-11 to I4-11 are methyl.

[0155] Preferably R.sup.e and R.sup.f in formulae I and I1-11 to I4-11 are t-butyl.

[0156] Preferably R.sup.g in formula I is H.

[0157] Further preferred compounds of formula I and its subformulae I1-11 to I4-11 are selected from the following preferred embodiments, including any combination thereof: [0158] The compounds contain exactly one polymerisable group (represented by the group P), [0159] the compounds contain exactly two polymerisable groups (represented by the groups P), [0160] the compounds contain exactly three polymerisable groups (represented by the groups P), [0161] P is acrylate or methacrylate, [0162] Sp is a single bond, [0163] Sp, when being different from a single bond, is selected from —(CH.sub.2).sub.a—, —(CH.sub.2).sub.a—O—, —(CH.sub.2).sub.a—CO—O—, —(CH.sub.2).sub.a—O—CO—, wherein a is 2, 3, 4, 5 or 6, and the O-atom or the CO-group, respectively, is connected to the benzene ring, [0164] R.sup.a, R.sup.b, R.sup.c and R.sup.d are methyl, [0165] R.sup.e and R.sup.f are t-butyl, [0166] R.sup.g is H, [0167] R.sup.g is methyl, [0168] m1 is 1 or 2, [0169] m1 is 0, [0170] m2 is 1 or 2, [0171] m2 is 0, [0172] Z.sup.1 denotes —CO—O—, —O—CO— or a single bond, preferably —CO—O—, [0173] Z.sup.2 denotes —CO—O—, —O—CO— or a single bond, preferably a single bond, [0174] L denotes F, Cl, CN, or alkyl or alkoxy with 1 to 6 C atoms that is optionally fluorinated, very preferably F, Cl, CN, CH.sub.3, OCH.sub.3, OCF.sub.3, OCF.sub.2H or OCFH.sub.2, most preferably F, [0175] one or more of L denotes P-Sp, [0176] one or more of L denote a group selected from formula 1, 2, 3 and 4, [0177] the compounds contain at least one group L or R that denotes P-Sp, [0178] r is 0 or 1, [0179] s is 0, [0180] t is 0 [0181] u is 0, 1 or 2.

[0182] The invention furthermore relates to novel compounds of formula I, especially those wherein m1 is different from 0 and/or T is a group selected from formulae (2), (3) and (4). The novel compounds of formula I can be selected from any of the above-mentioned preferred embodiments are any combination thereof.

[0183] Preferred novel compounds of formula I are those wherein m1 is different from 0, and is preferably 1 or 2.

[0184] Further preferred novel compounds of formula I are those selected from the preferred embodiments as described above and below.

[0185] Further preferred novel compounds of formula I are those selected from subformulae I1-1 to I1-10, I2-1 to I2-11, I3-1 to I3-11, I4-1 to I4-11.

[0186] Further preferred novel compounds of formula I are those selected from subformulae I1-1 to I1-10, I2-1 to I2-10, I3-1 to I3-10, I4-1 to I4-10.

[0187] The invention further relates to compounds of formula II

Pg-Sp-(A.sup.2-Z.sup.2-A.sup.1).sub.m1-Z.sup.1-T II

[0188] wherein T, Sp, A.sup.1,2, Z.sup.1,2 and m1 are as defined in formula I, P in the meanings of R and L is replaced by Pg, and Pg denotes OH, a protected hydroxyl group or a masked hydroxyl group.

[0189] Preferred compounds of formula II are selected from subformulae I1-1 to I4-11 as defined above, wherein P is replaced by Pg.

[0190] Suitable protected hydroxyl groups Pg are known to the person skilled in the art. Preferred protecting groups for hydroxyl groups are alkyl, alkoxyalkyl, acyl, alkylsilyl, arylsilyl and arylmethyl groups, especially 2-tetrahydropyranyl, methoxymethyl, methoxyethoxymethyl, acetyl, triisopropylsilyl, tert-butyl-dimethylsilyl or benzyl.

[0191] The term “masked hydroxyl group” is understood to mean any functional group that can be chemically converted into a hydroxyl group. Suitable masked hydroxyl groups Pg are known to the person skilled in the art.

[0192] The compounds of formula II are suitable as intermediates for the preparation of compounds of the formula I and its subformulae.

[0193] The invention further relates to the use of the compounds of formula II as intermediates for the preparation of compounds of the formula I and its subformulae.

[0194] The compounds and intermediates of the formulae I and II and sub-formulae thereof can be prepared analogously to processes known to the person skilled in the art and described in standard works of organic chemistry, such as, for example, in Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Thieme-Verlag, Stuttgart.

[0195] For example, compounds of formula I can be synthesised by esterification or etherification of the intermediates of formula II, wherein Pg denotes OH, using corresponding acids, acid derivatives, or halogenated compounds containing a polymerisable group P.

[0196] For example, acrylic or methacrylic esters can be prepared by esterification of the corresponding alcohols with acid derivatives like, for example, (meth)acryloyl chloride or (meth)acrylic anhydride in the presence of a base like pyridine or triethyl amine, and 4-(N,N-dimethylamino)pyridine (DMAP). Alternatively the esters can be prepared by esterification of the alcohols with (meth)acrylic acid in the presence of a dehydrating reagent, for example according to Steglich with dicyclohexylcarbodiimide (DCC), N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide (EDC) or N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride and DMAP.

[0197] Further suitable synthesis methods are shown in the Examples.

[0198] For the production of PSA displays, the polymerisable compounds cointained in the LC medium are polymerised or crosslinked (if one compound contains two or more polymerisable groups) by in-situ polymerisation in the LC medium between the substrates of the LC display, optionally while a voltage is applied to the electrodes.

[0199] 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.

[0200] A preferred PSA type LC display of the present invention comprises: [0201] a first substrate including a pixel electrode defining pixel areas, the pixel electrode being connected to a switching element disposed in each pixel area and optionally including a micro-slit pattern, and optionally a first alignment layer disposed on the pixel electrode, [0202] a second substrate including a common electrode layer, which may be disposed on the entire portion of the second substrate facing the first substrate, and optionally a second alignment layer, [0203] an LC layer disposed between the first and second substrates and including an LC medium comprising a polymerisable component A and a liquid-crystal component B as described above and below, wherein the polymerisable component A may also be polymerised.

[0204] The first and/or second alignment layer controls the alignment direction of the LC molecules of the LC layer. For example, in PS-VA displays the alignment layer is selected such that it imparts to the LC molecules homeotropic (or vertical) alignment (i.e. perpendicular to the surface) or tilted alignment. Such an alignment layer may for example comprise a polyimide, which may also be rubbed, or may be prepared by a photoalignment method.

[0205] The LC layer with the LC medium can be deposited between the substrates of the display by methods that are conventionally used by display manufacturers, for example the so-called one-drop-filling (ODF) method. The polymerisable component of the LC medium is then polymerised for example by UV photopolymerisation. The polymerisation can be carried out in one step or in two or more steps.

[0206] The PSA display may comprise further elements, like a colour filter, a black matrix, a passivation layer, optical retardation layers, transistor elements for addressing the individual pixels, etc., all of which are well known to the person skilled in the art and can be employed without inventive skill.

[0207] The electrode structure can be designed by the skilled person depending on the individual display type. For example for PS-VA displays a multi-domain orientation of the LC molecules can be induced by providing electrodes having slits and/or bumps or protrusions in order to create two, four or more different tilt alignment directions.

[0208] Upon polymerisation the polymerisable compounds form a crosslinked polymer, which causes a certain pretilt of the LC molecules in the LC medium. Without wishing to be bound to a specific theory, it is believed that at least a part of the crosslinked polymer, which is formed by the polymerisable compounds, will phase-separate or precipitate from the LC medium and form a polymer layer on the substrates or electrodes, or the alignment layer provided thereon. Microscopic measurement data (like SEM and AFM) have confirmed that at least a part of the formed polymer accumulates at the LC/substrate interface.

[0209] The polymerisation can be carried out in one step. It is also possible firstly to carry out the polymerisation, optionally while applying a voltage, in a first step in order to produce a pretilt angle, and subsequently, in a second polymerisation step without an applied voltage, to polymerise or crosslink the compounds which have not reacted in the first step (“end curing”).

[0210] Suitable and preferred polymerisation methods are, for example, thermal or photopolymerisation, preferably photopolymerisation, in particular UV induced photopolymerisation, which can be achieved by exposure of the polymerisable compounds to UV radiation.

[0211] Optionally one or more polymerisation initiators are added to the LC medium. Suitable conditions for the polymerisation and suitable types and amounts of initiators are known to the person skilled in the art and are described in the literature. Suitable for free-radical polymerisation are, for example, the commercially available photoinitiators Irgacure651®, Irgacure184®, Irgacure907®, Irgacure369® or Darocure1173® (Ciba AG). If a polymerisation initiator is employed, its proportion is preferably 0.001 to 5% by weight, particularly preferably 0.001 to 1% by weight.

[0212] The polymerisable compounds and components according to the invention are also suitable for polymerisation without an initiator, which is accompanied by considerable advantages, such, for example, lower material costs and in particular less contamination of the LC medium by possible residual amounts of the initiator or degradation products thereof. The polymerisation can thus also be carried out without the addition of an initiator. In a preferred embodiment, the LC medium thus does not contain a polymerisation initiator.

[0213] The LC medium may also comprise one or more stabilisers in order to prevent undesired spontaneous polymerisation of the RMs, for example during storage or transport. Suitable types and amounts of stabilisers are known to the person skilled in the art and are described in the literature.

[0214] Particularly suitable are, for example, the commercially available stabilisers from the Irganox® series (Ciba AG), such as, for example, Irganox® 1076. If stabilisers are employed, their proportion, based on the total amount of RMs or the polymerisable component (component A), is preferably 10-500,000 ppm, particularly preferably 50-50,000 ppm.

[0215] The LC media according to the present invention preferably do not contain any other compounds with stabilising groups than those of formula I.

[0216] The polymerisable component contained in the LC media according to the present invention does in particular show good UV absorption in, and are therefore especially suitable for, a process of preparing a PSA display including one or more of the following features:

[0217] the LC medium is exposed to UV light in the display in a 2-step process, including a first UV exposure step (“UV-1 step”) to generate the tilt angle, and a second UV exposure step (“UV-2 step”) to finish polymerization,

[0218] the LC medium is exposed to UV light in the display generated by an energy-saving UV lamp (also known as “green UV lamps”). These lamps are characterized by a relative low intensity (1/100-1/10 of a conventional UV1 lamp) in their absorption spectra from 300-380 nm, and are preferably used in the UV2 step, but are optionally also used in the UV1 step when avoiding high intensity is necessary for the process.

[0219] the LC medium is exposed to UV light in the display generated by a UV lamp with a radiation spectrum that is shifted to longer wavelengths, preferably 340 nm or more, to avoid short UV light exposure in the PSA process.

[0220] Both using lower intensity and a UV shift to longer wavelengths protect the organic layer against damage that may be caused by the UV light.

[0221] A preferred embodiment of the present invention relates to a process for preparing a PSA display as described above and below, comprising one or more of the following features:

[0222] the LC medium is exposed to UV light in a 2-step process, including a first UV exposure step (“UV-1 step”) to generate the tilt angle, and a second UV exposure step (“UV-2 step”) to finish polymerization,

[0223] the LC medium is exposed to UV light generated by a UV lamp having an intensity of from 0.5 mW/cm.sup.2 to 10 mW/cm.sup.2 in the wavelength range from 300-380 nm, preferably used in the UV2 step, and optionally also in the UV1 step,

[0224] the LC medium is exposed to UV light having a wavelength of 340 nm or more, and preferably 400 nm or less.

[0225] This preferred process can be carried out for example by using the desired UV lamps or by using a band pass filter and/or a cut-off filter, which are substantially transmissive for UV light with the respective desired wavelength(s) and are substantially blocking light with the respective undesired wavelengths. For example, when irradiation with UV light of wavelengths λ of 300-400 nm is desired, UV exposure can be carried out using a wide band pass filter being substantially transmissive for wavelengths 300 nm<λ<400 nm. When irradiation with UV light of wavelength λ of more than 340 nm is desired, UV exposure can be carried out using a cut-off filter being substantially transmissive for wavelengths λ>340 nm.

[0226] “Substantially transmissive” means that the filter transmits a substantial part, preferably at least 50% of the intensity, of incident light of the desired wavelength(s). “Substantially blocking” means that the filter does not transmit a substantial part, preferably at least 50% of the intensity, of incident light of the undesired wavelengths. “Desired (undesired) wavelength” e.g. in case of a band pass filter means the wavelengths inside (outside) the given range of λ, and in case of a cut-off filter means the wavelengths above (below) the given value of λ.

[0227] This preferred process enables the manufacture of displays by using longer UV wavelengths, thereby reducing or even avoiding the hazardous and damaging effects of short UV light components.

[0228] UV radiation energy is in general from 6 to 100 J, depending on the production process conditions.

[0229] Preferably the LC medium of the present invention essentially consists of a polymerisable component A), or one or more polymerisable compounds of formula I, preferably selected from formulae I1-1 to I4-11, very preferably from formulae I1-1 to I1-11, and optionally one or more polymerisable compounds different from formula I, and an LC component B), or LC host mixture, as described above and below.

[0230] However, the LC medium may additionally comprise one or more further components or additives, preferably selected from the list including but not limited to co-monomers, chiral dopants, polymerisation initiators, inhibitors, stabilizers, surfactants, wetting agents, lubricating agents, dispersing agents, hydrophobing agents, adhesive agents, flow improvers, defoaming agents, deaerators, diluents, reactive diluents, auxiliaries, colourants, dyes, pigments and nanoparticles.

[0231] Preference is furthermore given to LC media in which the liquid-crystalline component B) or the LC host mixture has a nematic LC phase, and preferably has no chiral liquid-crystal phase.

[0232] The LC component B), or LC host mixture, is preferably a nematic LC mixture.

[0233] Preference is furthermore given to achiral compounds of formula I, and to LC media in which the compounds of component A and/or B are selected exclusively from the group consisting of achiral compounds.

[0234] Preferably the proportion of the polymerisable component A in the LC medium is from >0 to <5%, very preferably from >0 to <1%, most preferably from 0.001 to 0.5%.

[0235] Preferably the proportion of the LC component B in the LC medium is from 95 to <100%, very preferably from 99 to <100%.

[0236] In a preferred embodiment of the present invention, the LC medium and/or polymerisable component A does not contain any other polymerisable compounds than those of formula I.

[0237] In this preferred embodiment, the compounds of formula I are preferably selected from those wherein T is a group of formula (1), (2) or (3).

[0238] Furthermore, in this preferred embodiment, the compounds of formula I are selected from those containing at least one groups P-Sp-.

[0239] In another preferred embodiment of the present invention, the LC medium and/or its polymerisable component A contain one or more compounds of formula I and one or more polymerisable compounds that are different from formula I.

[0240] In this preferred embodiment, the compounds of formula I are preferably selected from those wherein T is of formula (1), (2) or (3), very preferably of formula (1).

[0241] The polymerisable compounds that are different from formula I, hereinafter also referred to as “co-monomers”, are preferably selected from RMs.

[0242] Suitable and preferred co-monomers for use in LC media together with the compounds of formula I are selected from the following formulae:

##STR00018## ##STR00019## ##STR00020## ##STR00021## ##STR00022##

in which the individual radicals have the following meanings: [0243] P.sup.1, P.sup.2 and P.sup.3 each, independently of one another, denote an acrylate or methacrylate group, [0244] Sp.sup.1, Sp.sup.2 and Sp.sup.3 each, independently of one another, denote a single bond or a spacer group having one of the meanings indicated above and below for Sp, and particularly preferably denote —(CH.sub.2).sub.p1—, —(CH.sub.2).sub.p1—O—, —(CH.sub.2).sub.p1—CO—O—, —(CH.sub.2).sub.p1—O—CO— or —(CH.sub.2).sub.p1—O—CO—O—, in which p1 is an integer from 1 to 12, where, in addition, one or more of the radicals P.sup.1-Sp.sup.1-, P.sup.1-Sp.sup.2- and P.sup.3-Sp.sup.3- may denote R.sup.aa, with the proviso that at least one of the radicals P.sup.1-Sp.sup.1-, P.sup.2-Sp.sup.2 and P.sup.3-Sp.sup.3- present is different from R.sup.aa,

[0245] R.sup.aa denotes 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)—, —C≡C—, —N(R.sup.0)—, —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— 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.1-S;.sup.1-, particularly preferably straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, 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), [0246] R.sup.0, R.sup.00 each, independently of one another and identically or differently on each occurrence, denote H or alkyl having 1 to 12 C atoms, [0247] R.sup.y and R.sup.z each, independently of one another, denote H, F, CH.sub.3 or CF.sub.3, [0248] X.sup.1, X.sup.2 and X.sup.3 each, independently of one another, denote —CO—O—, —O—CO— or a single bond, [0249] Z.sup.1 denotes —O—, —CO—, —C(RYR.sup.z)— or —CF.sub.2CF.sub.2—, [0250] Z.sup.2 and Z.sup.3 each, independently of one another, denote —CO—O—, —O—CO—, —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, [0251] L on each occurrence, identically or differently, denotes F, Cl, CN or straight—chain or branched, optionally mono- or poly-fluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms, preferably F, [0252] L′ and L″ each, independently of one another, denote H, F or Cl, [0253] r denotes 0, 1, 2, 3 or 4, [0254] s denotes 0, 1, 2 or 3, [0255] t denotes 0, 1 or 2, [0256] x denotes 0 or 1.

[0257] Especially preferred are direactive compounds of formulae M1 to M14, in particular M2, M3, M10, M12, M13, M15 and M16, very preferably M2.

[0258] Further preferred are trireactive compounds M15 to M30, in particular M17, M18, M19, M22, M23, M24, M25, M29 and M30.

[0259] In the compounds of formulae M1 to M30 the group

##STR00023##

is preferably

##STR00024##

wherein 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 P-Sp-, very preferably F, Cl, CN, CH.sub.3, C.sub.2H.sub.5, OCH.sub.3, COCH.sub.3, OCF.sub.3 or P-Sp-, more preferably F, Cl, CH.sub.3, OCH.sub.3, COCH.sub.3 or OCF.sub.3 , especially F or CH.sub.3.

[0260] Especially preferred co-monomers of formulae M1-M30 are selected from the following formulae

##STR00025## ##STR00026## ##STR00027## ##STR00028## ##STR00029## ##STR00030## ##STR00031## ##STR00032## ##STR00033##

[0261] Particular preference is given to a polymerisable component or an LC medium comprising one, two or three polymerisable compounds of formula I, preferably selected from formulae I1-1 to I4-11, very preferably from formulae I1-1 to I1-11, and one, two or three polymerisable compounds that are different from formula I and are preferably selected from formulae M1-M30, very preferably from formulae RM-1 to RM-71, most preferably selected from formula M2, in particular selected from formula RM-1.

[0262] Preference is furthermore given to LC media in which the polymerisable component A consists of polymerisable compounds of formula I, preferably selected from formulae I1-1 to I4-11, very preferably from formulae I1-1 to I1-11, and polymerisable compounds of formula M2, especially those of formula RM-1.

[0263] Preference is furthermore given to LC media in which the polymerisable component A consists only of polymerisable compounds of formula I, preferably selected from formulae I1-1 to I4-11, very preferably from formulae I2-1 to I1-11.

[0264] Preferably the proportion of polymerisable compounds of formula I in the LC medium is from >0 to <3%, very preferably from >0 to ≦1%, most preferably from 0.001 to 0.5%.

[0265] In the preferred embodiments where the LC medium or the polymerisable component A does not contain any other polymerisable compounds except those of formula I, the proportion of the compounds of formula I in the LC medium is preferably from >0 to <3%, very preferably from >0 to ≦1%, most preferably from 0.001 to 0.5%.

[0266] In the preferred embodiments where the LC medium or the polymerisable component A contains one or more compounds of formula I and one or more polymerisable compounds different from formula I, the proportion of compounds of formula I in the LC medium is preferably from >0 to <1%, very preferably from >0 to ≦0.3%, most preferably from 0.001 to 0.15%.

[0267] Preferably the proportion of polymerisable compounds different from formula I, preferably selected from formulae M1-M30, in the LC medium is from >0 to <3%, very preferably from >0 to <1%, most preferably from 0.05 to 0.5%.

[0268] Besides the polymerisable compounds described above, the LC media for use in the LC displays according to the invention comprise an LC host mixture comprising one or more, preferably two or more LC compounds which are selected from low-molecular-weight compounds that are unpolymerisable. These LC compounds are selected such that they stable and/or unreactive to a polymerisation reaction under the conditions applied to the polymerisation of the polymerisable compounds.

[0269] In principle, any LC mixture which is suitable for use in conventional displays is suitable as host mixture. Suitable LC mixtures are known to the person skilled in the art and are described in the literature, for example mixtures in VA displays in EP 1 378 557 A1 and mixtures for OCB displays in EP 1 306 418 A1 and DE 102 24 046 A1.

[0270] The polymerisable compounds and components of the present invention are especially suitable for use in an LC host mixture that comprises one or more mesogenic or LC compounds comprising an alkenyl group (hereinafter also referred to as “alkenyl compounds”), wherein said alkenyl group is stable to a polymerisation reaction under the conditions used for polymerisation of the compounds of formula I and of the other polymerisable compounds contained in the LC medium. Compared to RMs known from prior art the polymerisable compounds and components of the present invention do in such an LC host mixture exhibit improved properties, like solubility, reactivity or capability of generating a tilt angle.

[0271] Thus, in a preferred embodiment of the present invention, the LC medium comprises one or more mesogenic or liquid-crystalline compounds comprising an alkenyl group, (“alkenyl compound”), where this alkenyl group is preferably stable to a polymerisation reaction under the conditions used for the polymerisation of the polymerisable compounds of formula I and of the other polymerisable compounds contained in the LC medium.

[0272] The alkenyl groups in the alkenyl compounds are preferably selected from straight-chain, branched or cyclic alkenyl, in particular having 2 to 25 C atoms, particularly preferably having 2 to 12 C atoms, in which, in addition, one or more non-adjacent CH.sub.2 groups may be replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a way that 0 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 and/or Cl.

[0273] Preferred alkenyl groups are straight-chain alkenyl having 2 to 7 C atoms and cyclohexenyl, in particular ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, 1,4-cyclohexen-1-yl and 1,4-cyclohexen-3-yl.

[0274] The concentration of compounds containing an alkenyl group in the LC host mixture (i.e. without any polymerisable compounds) is preferably from 5% to 100%, very preferably from 20% to 60%.

[0275] Especially preferred are LC mixtures containing 1 to 5, preferably 1, 2 or 3 compounds having an alkenyl group.

[0276] The mesogenic and LC compounds containing an alkenyl group are preferably selected from the following formulae:

##STR00034##

in which the individual radicals, on each occurrence identically or differently, each, independently of one another, have the following meaning:

##STR00035## [0277] RA1 alkenyl having 2 to 9 C atoms or, if at least one of the rings X, Y and Z denotes cyclohexenyl, also one of the meanings of R.sup.A2, [0278] RA2 alkyl having 1 to 12 C atoms, in which, in addition, one or two non-adjacent CH.sub.2 groups may be replaced by —O—, —CH═CH—, —CO—, —OCO— or —COO— in such a way that O atoms are not linked directly to one another, [0279] Z.sup.x —CH.sub.2CH.sub.2—, —CH═CH—, —CF.sub.2O—, —OCF.sub.2—, —CH.sub.2O—, —OCH.sub.2—, —CO—O—, —O—CO—, —C.sub.2F.sub.4—, —CF═CF—, —CH═CH—CH.sub.2O—, or a single bond, preferably a single bond, [0280] L.sup.1-4 each, independently of one another, H, F, Cl, OCF.sub.3, CF.sub.3, CH.sub.3, CH.sub.2F or CHF.sub.2H, preferably H, F or Cl, [0281] x 1 or 2, [0282] z 0 or 1.

[0283] R.sup.A2 is preferably straight-chain alkyl or alkoxy having 1 to 8 C atoms or straight-chain alkenyl having 2 to 7 C atoms.

[0284] The LC medium preferably comprises no compounds containing a terminal vinyloxy group (—O—CH═CH.sub.2), in particular no compounds of the formula AN or AY in which R.sup.A1 or R.sup.A2 denotes or contains a terminal vinyloxy group (—O—CH═CH.sub.2).

[0285] Preferably, L.sup.1 and L.sup.2 denote F, or one of L.sup.1 and L.sup.2 denotes F and the other denotes Cl, and L.sup.3 and L.sup.4 denote F, or one of L.sup.3 and L.sup.4 denotes F and the other denotes Cl.

[0286] The compounds of the formula AN are preferably selected from the following sub-formulae:

##STR00036## ##STR00037##

in which alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, and alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-7 C atoms. Alkenyl and alkenyl* preferably denote CH.sub.2═CH—, CH.sub.2═CHCH.sub.2CH.sub.2—, CH.sub.3—CH═CH—, CH.sub.3—CH.sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.3—CH═CH— or CH.sub.3—CH═CH—(CH.sub.2).sub.2—.

[0287] Very preferred compounds of the formula AN are selected from the following sub-formulae:

##STR00038##

in which m denotes 1, 2, 3, 4, 5 or 6, i denotes 0, 1, 2 or 3, and R.sup.b1 denotes H, CH.sub.3 or C.sub.2H.sub.5.

[0288] Very particularly preferred compounds of the formula AN are selected from the following sub-formulae:

##STR00039##

[0289] Most preferred are compounds of formula AN1a2 and AN1a5.

[0290] The compounds of the formula AY are preferably selected from the following sub-formulae:

##STR00040## ##STR00041## ##STR00042## ##STR00043##

[0291] Very preferred compounds of the formula AY are selected from the following sub—formulae:

##STR00044##

in which m and n each, independently of one another, denote 1, 2, 3, 4, 5 or 6, and alkenyl denotes CH.sub.2═CH—, CH.sub.2═CHCH.sub.2CH.sub.2—, CH.sub.3—CH═CH—, CH.sub.3—CH.sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.3—CH═CH— or CH.sub.3—CH═CH—(CH.sub.2).sub.2—.

[0292] Besides the polymerisable component A) as described above, the LC media according to the present invention comprise an LC component B), or LC host mixture, comprising one or more, preferably two or more LC compounds which are selected from low-molecular-weight compounds that are unpolymerisable. These LC compounds are selected such that they stable and/or unreactive to a polymerisation reaction under the conditions applied to the polymerisation of the polymerisable compounds.

[0293] In a first preferred embodiment the LC medium contains an LC component B), or LC host mixture, based on compounds with negative dielectric anisotropy. Such LC media are especially suitable for use in PS-VA and PS-UB-FFS displays. Particularly preferred embodiments of such an LC medium are those of sections a)-z) below: [0294] a) LC medium which comprises one or more compounds of the formulae CY and/or PY:

##STR00045##

wherein [0295] a denotes 1 or 2, [0296] b denotes 0 or 1,

##STR00046## [0297] R.sup.1 and R.sup.2 each, independently of one another, denote alkyl having 1 to 12 C atoms, where, in addition, one or two non-adjacent CH.sub.2 groups may be replaced by —O—, —CH═CH—, —CO—, —OCO—or —COO— in such a way that O atoms are not linked directly to one another, preferably alkyl or alkoxy having 1 to 6 C atoms, [0298] Z.sup.x and Z.sup.y each, independently of one another, denote —CH.sub.2CH.sub.2—, —CH═CH—, —CF.sub.2O—, —OCF.sub.2—, —CH.sub.2O—, —OCH.sub.2—, —CO—O—, —O—CO—, —C.sub.2F.sub.4—, —CF═CF—, —CH═CH—CH.sub.2O— or a single bond, preferably a single bond, [0299] L.sup.1-4 each, independently of one another, denote F, Cl, OCF.sub.3, CF.sub.3, CH.sub.3, CH.sub.2F, CHF.sub.2.

[0300] Preferably, both L.sup.1 and L.sup.2 denote F or one of L.sup.1 and L.sup.2 denotes F and the other denotes Cl, or both L.sup.3 and L.sup.4 denote F or one of L.sup.3 and L.sup.4 denotes F and the other denotes Cl.

[0301] The compounds of the formula CY are preferably selected from the group consisting of the following sub-formulae:

##STR00047## ##STR00048## ##STR00049## ##STR00050##

in which 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.2═CH—, CH.sub.2═CHCH.sub.2CH.sub.2—, CH.sub.3—CH═CH—, CH.sub.3—CH.sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.3—CH═CH— or CH.sub.3—CH═CH—(CH.sub.2).sub.2—.

[0302] The compounds of the formula PY are preferably selected from the group consisting of the following sub-formulae:

##STR00051## ##STR00052## ##STR00053##

in which 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.2═CH—, CH.sub.2═CHCH.sub.2CH.sub.2—, CH.sub.3—CH═CH—, CH.sub.3—CH.sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.3—CH═CH— or CH.sub.3—CH═CH—(CH.sub.2).sub.2—. [0303] b) LC medium which additionally comprises one or more compounds of the following formula:

##STR00054##

in which the individual radicals have the following meanings:

##STR00055## [0304] R.sup.3 and R.sup.4 each, independently of one another, denote alkyl having 1 to 12 C atoms, in which, in addition, one or two non-adjacent CH.sub.2 groups may be replaced by —O—, —CH═CH—, —CO—, —O—CO— or —CO—O— in such a way that 0 atoms are not linked directly to one another, [0305] Z.sup.y denotes —CH.sub.2CH.sub.2—, —CH═CH—, —CF.sub.2O—, —OCF.sub.2—, —CH.sub.2O—, —OCH.sub.2—, —CO—O—, —O—CO—, —C.sub.2F.sub.4—, —CF═CF—, —CH═CH—CH.sub.2O— or a single bond, preferably a single bond.

[0306] The compounds of the formula ZK are preferably selected from the group consisting of the following sub-formulae:

##STR00056##

in which 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. Alkenyl preferably denotes CH.sub.2═CH—, CH.sub.2═CHCH.sub.2CH.sub.2—, CH.sub.3—CH═CH—, CH.sub.3—CH.sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.3—CH═CH— or CH.sub.3—CH═CH—(CH.sub.2).sub.2—.

[0307] Especially preferred are compounds of formula ZK1.

[0308] Particularly preferred compounds of formula ZK are selected from the following sub-formulae:

##STR00057##

wherein the propyl, butyl and pentyl groups are straight-chain groups.

[0309] Most preferred are compounds of formula ZK1a. [0310] c) LC medium which additionally comprises one or more compounds of the following formula:

##STR00058##

in which the individual radicals on each occurrence, identically or differently, have the following meanings: [0311] R.sup.5 and R.sup.6 each, independently of one another, denote alkyl having 1 to 12 C atoms, where, in addition, one or two non-adjacent CH.sub.2 groups may be replaced by —O—, —CH═CH—, —CO—, —OCO— or —COO— in such a way that O atoms are not linked directly to one another, preferably alkyl or alkoxy having 1 to 6 C atoms,

##STR00059##

and [0312] e denotes 1 or 2.

[0313] The compounds of the formula DK are preferably selected from the group consisting of the following sub-formulae:

##STR00060## ##STR00061##

in which 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. Alkenyl preferably denotes CH.sub.2═CH—, CH.sub.2═CHCH.sub.2CH.sub.2—, CH.sub.3—CH═CH—, CH.sub.3—CH.sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.3—CH═CH— or CH.sub.3—CH═CH—(CH.sub.2).sub.2—. [0314] d) LC medium which additionally comprises one or more compounds of the following formula:

##STR00062##

in which the individual radicals have the following meanings:

##STR00063##

with at least one ring F being different from cyclohexylene, [0315] f denotes 1 or 2, [0316] R.sup.1 and R.sup.2 each, independently of one another, denote alkyl having 1 to 12 C atoms, where, in addition, one or two non-adjacent CH.sub.2 groups may be replaced by —O—, —CH═CH—, —CO—, —OCO— or —COO— in such a way that O atoms are not linked directly to one another, [0317] Z.sup.x denotes —CH.sub.2CH.sub.2—, —CH═CH—, —CF.sub.2O—, —OCF.sub.2—, —CH.sub.2O—, —OCH.sub.2—, —CO—O—, —O—CO—, —C.sub.2F.sub.4—, —CF═CF—, —CH═CH—CH.sub.2O— or a single bond, preferably a single bond, [0318] L.sup.1 and L.sup.2 each, independently of one another, denote F, Cl, OCF.sub.3, CF.sub.3, CH.sub.3, CH.sub.2F, CHF.sub.2.

[0319] Preferably, both radicals L.sup.1 and L.sup.2 denote F or one of the radicals L.sup.1 and L.sup.2 denotes F and the other denotes Cl.

[0320] The compounds of the formula LY are preferably selected from the group consisting of the following sub-formulae:

##STR00064## ##STR00065## ##STR00066##

in which R.sup.1 has the meaning indicated above, alkyl denotes a straight-chain alkyl radical having 1-6 C atoms, (O) denotes an oxygen atom or a single bond, and v denotes an integer from 1 to 6. R.sup.1 preferably denotes straight—chain alkyl having 1 to 6 C atoms or straight—chain alkenyl having 2 to 6 C atoms, in particular CH.sub.3, C.sub.2H.sub.5, n-C.sub.3H.sub.7, n-C.sub.4H.sub.9, n-C.sub.5H.sub.11, CH.sub.2═CH—, CH.sub.2═CHCH.sub.2CH.sub.2—, CH.sub.3—CH═CH—, CH.sub.3—CH.sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.3—CH═CH— or CH.sub.3—CH═CH—(CH.sub.2).sub.2—. [0321] e) LC medium which additionally comprises one or more compounds selected from the group consisting of the following formulae:

##STR00067##

in which alkyl denotes C.sub.1-6-alkyl, L.sup.x denotes H or F, and X denotes F, Cl, OCF.sub.3, OCHF.sub.2 or OCH═CF.sub.2. Particular preference is given to compounds of the formula G1 in which X denotes F. [0322] f) LC medium which additionally comprises one or more compounds selected from the group consisting of the following formulae:

##STR00068## ##STR00069##

in which R.sup.5 has one of the meanings indicated above for R.sup.1, alkyl denotes C.sub.1-6-alkyl, d denotes 0 or 1, and z and m each, independently of one another, denote an integer from 1 to 6. R.sup.5 in these compounds is particularly preferably C.sub.1-6-alkyl or -alkoxy or C.sub.2-6-alkenyl, d is preferably 1. The LC medium according to the invention preferably comprises one or more compounds of the above-mentioned formulae in amounts of ≧5% by weight. [0323] g) LC medium which additionally comprises one or more biphenyl compounds selected from the group consisting of the following formulae:

##STR00070##

in which alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, and alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms. Alkenyl and alkenyl* preferably denote CH.sub.2═CH—, CH.sub.2═CHCH.sub.2CH.sub.2—, CH.sub.3—CH═CH—, CH.sub.3—CH.sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.3—CH═CH— or CH.sub.3—CH═CH—(CH.sub.2).sub.2—.

[0324] The proportion of the biphenyls of the formulae B1 to B3 in the LC mixture is preferably at least 3% by weight, in particular 5% by weight.

[0325] The compounds of the formula B2 are particularly preferred.

[0326] The compounds of the formulae B1 to B3 are preferably selected from the group consisting of the following sub-formulae:

##STR00071##

in which alkyl* denotes an alkyl radical having 1-6 C atoms. The medium according to the invention particularly preferably comprises one or more compounds of the formulae B1a and/or B2c. [0327] h) LC medium which additionally comprises one or more terphenyl compounds of the following formula:

##STR00072##

in which R.sup.5 and R.sup.6 each, independently of one another, have one of the meanings indicated above, and

##STR00073##

each, independently of one another, denote

##STR00074##

in which L.sup.5 denotes F or Cl, preferably F, and L.sup.6 denotes F, Cl, OCF.sub.3, CF.sub.3, CH.sub.3, CH.sub.2F or CHF.sub.2, preferably F.

[0328] The compounds of the formula T are preferably selected from the group consisting of the following sub-formulae:

##STR00075## ##STR00076## ##STR00077##

in which R denotes a straight-chain alkyl or alkoxy radical having 1-7 C atoms, R* denotes a straight-chain alkenyl radical having 2-7 C atoms, (O) denotes an oxygen atom or a single bond, and m denotes an integer from 1 to 6. R* preferably denotes CH.sub.2═CH—, CH.sub.2═CHCH.sub.2CH.sub.2—, CH.sub.3—CH═CH—, CH.sub.3—CH.sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.2—CH═CH—, CH.sub.3—(CH.sub.2).sub.3—CH═CH— or CH.sub.3—CH═CH—(CH.sub.2).sub.2—.

[0329] R preferably denotes methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy or pentoxy.

[0330] The LC medium according to the invention preferably comprises the terphenyls of the formula T and the preferred sub-formulae thereof in an amount of 0.5-30% by weight, in particular 1-20% by weight.

[0331] Particular preference is given to compounds of the formulae T1, T2, T3 and T21. In these compounds, R preferably denotes alkyl, furthermore alkoxy, each having 1-5 C atoms.

[0332] The terphenyls are preferably employed in mixtures according to the invention if the Δn value of the mixture is to be ≧0.1. Preferred mixtures comprise 2-20% by weight of one or more terphenyl compounds of the formula T, preferably selected from the group of compounds T1 to T22. [0333] i) LC medium which additionally comprises one or more quaterphenyl compounds selected from the group consisting of the following formulae:

##STR00078##

wherein [0334] R.sup.Q is alkyl, alkoxy, oxaalkyl or alkoxyalkyl having 1 to 9 C atoms or alkenyl or alkenyloxy having 2 to 9 C atoms, all of which are optionally fluorinated, [0335] X.sup.Q is F, Cl, halogenated alkyl or alkoxy having 1 to 6 C atoms or halogenated alkenyl or alkenyloxy having 2 to 6 C atoms, [0336] L.sup.Q1 to L.sup.Q6 independently of each other are H or F, with at least one of L.sup.Q1 to L.sup.Q6 being F.

[0337] Preferred compounds of formula Q are those wherein R.sup.Q denotes straight-chain alkyl with 2 to 6 C-atoms, very preferably ethyl, n-propyl or n-butyl.

[0338] Preferred compounds of formula Q are those wherein L.sup.Q3 and L.sup.Q4 are F. Further preferred compounds of formula Q are those wherein L.sup.Q3, L.sup.Q4 and one or two of L.sup.Q1 and L.sup.Q2 are F.

[0339] Preferred compounds of formula Q are those wherein X.sup.Q denotes F or OCF.sub.3, very preferably F.

[0340] The compounds of formula Q are preferably selected from the following subformulae

##STR00079##

wherein R.sup.Q has one of the meanings of formula Q or one of its preferred meanings given above and below, and is preferably ethyl, n-propyl or n-butyl.

[0341] Especially preferred are compounds of formula Q1, in particular those wherein R.sup.Q is n-propyl.

[0342] Preferably the proportion of compounds of formula Q in the LC medium is from >0 to ≦5% by weight, very preferably from 0.1 to 2% by weight, most preferably from 0.2 to 1.5% by weight.

[0343] Preferably the LC medium contains 1 to 5, preferably 1 or 2 compounds of formula Q.

[0344] The addition of quaterphenyl compounds of formula Q to the LC medium mixture enables to reduce ODF mura, whilst maintaining high UV absorption, enabling quick and complete polymerisation, enabling strong and quick tilt angle generation, and increasing the UV stability of the LC medium.

[0345] Besides the addition of compounds of formula Q, which have positive dielectric anisotropy, to the LC medium with negative dielectric anisotropy allows a better control of the values of the dielectric constants ε.sub.∥ and ε.sub.⊥, and in particular enables to achieve a high value of the dielectric constant ε.sub.∥ while keeping the dielectric anisotropy Δε constant, thereby reducing the kick-back voltage and reducing image sticking. [0346] k) LC medium which additionally comprises one or more compounds selected from the group consisting of the following formulae:

##STR00080## ##STR00081##

in which R.sup.1 and R.sup.2 have the meanings indicated above and preferably each, independently of one another, denote straight-chain alkyl having 1 to 6 C atoms or straight-chain alkenyl having 2 to 6 C atoms.

[0347] Preferred media comprise one or more compounds selected from the formulae O1, O3 and O4. [0348] l) LC medium which additionally comprises one or more compounds of the following formula:

##STR00082##

in which

##STR00083##

[0349] R.sup.9 denotes H, CH.sub.3, C.sub.2H.sub.5 or n-C.sub.3H.sub.7, (F) denotes an optional fluorine substituent, and q denotes 1, 2 or 3, and R.sup.7 has one of the meanings indicated for R.sup.1, preferably in amounts of >3% by weight, in particular ≧5% by weight and very particularly preferably 5-30% by weight.

[0350] Particularly preferred compounds of the formula Fl are selected from the group consisting of the following sub-formulae:

##STR00084##

in which R.sup.7 preferably denotes straight-chain alkyl, and R.sup.9 denotes CH.sub.3, C.sub.2H.sub.5 or n-C.sub.3H.sub.7. Particular preference is given to the compounds of the formulae FI1, FI2 and FI3. [0351] m) LC medium which additionally comprises one or more compounds selected from the group consisting of the following formulae:

##STR00085##

in which R.sup.8 has the meaning indicated for R.sup.1, and alkyl denotes a straight-chain alkyl radical having 1-6 C atoms. [0352] n) LC medium which additionally comprises one or more compounds which contain a tetrahydronaphthyl or naphthyl unit, such as, for example, the compounds selected from the group consisting of the following formulae:

##STR00086## ##STR00087##

in which [0353] R.sup.10 and R.sup.11 each, independently of one another, denote alkyl having 1 to 12 C atoms, where, in addition, one or two non-adjacent CH.sub.2 groups may be replaced by —O—, —CH═CH—, —CO—, —OCO— or —COO— in such a way that 0 atoms are not linked directly to one another, preferably alkyl or alkoxy having 1 to 6 C atoms,

[0354] and R.sup.1° and R.sup.11 preferably denote straight-chain alkyl or alkoxy having 1 to 6 C atoms or straight-chain alkenyl having 2 to 6 C atoms, and [0355] Z.sup.1 and Z.sup.2 each, independently of one another, denote —C.sub.2H.sub.4—, —CH═CH—, —(CH.sub.2).sub.4—, —(CH.sub.2).sub.3O—, —O(CH.sub.2).sub.3—, —CH═CH—CH.sub.2CH.sub.2—, —CH.sub.2CH.sub.2CH═CH—, —CH.sub.2O—, —OCH.sub.2—, —CO—O—, —O—CO—, —C.sub.2F.sub.4—, —CF═CF—, —CF═CH—, —CH═CF—, —CH.sub.2— or a single bond. [0356] o) LC medium which additionally comprises one or more difluorodibenzo-chromans and/or chromans of the following formulae:

##STR00088##

in which [0357] R.sup.11 and R.sup.12 each, independently of one another, have one of the meanings indicated above for R.sup.11, [0358] ring M is trans-1,4-cyclohexylene or 1,4-phenylene, [0359] Z.sup.m —C.sub.2H.sub.4—, —CH.sub.2O—, —OCH.sub.2—, —CO—O— or —O—CO—, [0360] c is 0, 1 or 2,

[0361] preferably in amounts of 3 to 20% by weight, in particular in amounts of 3 to 15% by weight.

[0362] Particularly preferred compounds of the formulae BC, CR and RC are selected from the group consisting of the following sub-formulae:

##STR00089## ##STR00090## ##STR00091##

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

[0363] Very particular preference is given to mixtures comprising one, two or three compounds of the formula BC-2. [0364] p) LC medium which additionally comprises one or more fluorinated phenanthrenes and/or dibenzofurans of the following formulae:

##STR00092##

in which R.sup.11 and R.sup.12 each, independently of one another, have one of the meanings indicated above for R.sup.11, b denotes 0 or 1, L denotes F, and r denotes 1, 2 or 3.

[0365] Particularly preferred compounds of the formulae PH and BF are selected from the group consisting of the following sub-formulae:

##STR00093##

in which R and R′ each, independently of one another, denote a straight-chain alkyl or alkoxy radical having 1-7 C atoms. [0366] q) LC medium which additionally comprises one or more monocyclic compounds of the following formula

##STR00094##

wherein [0367] R.sup.1 and R.sup.2 each, independently of one another, denote alkyl having 1 to 12 C atoms, where, in addition, one or two non-adjacent CH.sub.2 groups may be replaced by —O—, —CH═CH—, —CO—, —OCO— or —COO— in such a way that O atoms are not linked directly to one another, preferably alkyl or alkoxy having 1 to 6 C atoms, [0368] L.sup.1 and L.sup.2 each, independently of one another, denote F, Cl, OCF.sub.3, CF.sub.3, CH.sub.3, CH.sub.2F, CHF.sub.2.

[0369] Preferably, both L.sup.1 and L.sup.2 denote F or one of L.sup.1 and L.sup.2 denotes F and the other denotes Cl,

[0370] The compounds of the formula Y are preferably selected from the group consisting of the following sub-formulae:

##STR00095## ##STR00096##

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

[0371] Particularly preferred compounds of the formula Y are selected from the group consisting of the following sub-formulae:

##STR00097##

wherein Alkoxy preferably denotes straight-chain alkoxy with 3, 4, or 5 C atoms. [0372] r) LC medium which, apart from the polymerisable compounds according to the invention, in particular of the formula I or sub-formulae thereof and the comonomers, comprises no compounds which contain a terminal vinyloxy group (—O—CH═CH.sub.2). [0373] s) LC medium which comprises 1 to 5, preferably 1, 2 or 3, polymerisable compounds, preferably selected from polymerisable compounds according to the invention, in particular of the formula I or sub-formulae thereof. [0374] t) LC medium in which the proportion of polymerisable compounds, in particular of the formula I or sub-formulae thereof, in the mixture as a whole is 0.05 to 5%, preferably 0.1 to 1%. [0375] u) LC medium which comprises 1 to 8, preferably 1 to 5, compounds of the formulae CY1, CY2, PY1 and/or PY2. The proportion of these compounds in the mixture as a whole is preferably 5 to 60%, particularly preferably 10 to 35%. The content of these individual compounds is preferably in each case 2 to 20%. [0376] v) LC medium which comprises 1 to 8, preferably 1 to 5, compounds of the formulae CY9, CY10, PY9 and/or PY10. The proportion of these compounds in the mixture as a whole is preferably 5 to 60%, particularly preferably 10 to 35%. The content of these individual compounds is preferably in each case 2 to 20%. [0377] w) LC medium which comprises 1 to 10, preferably 1 to 8, compounds of the formula ZK, in particular compounds of the formulae ZK1, ZK2 and/or ZK6. The proportion of these compounds in the mixture as a whole is preferably 3 to 25%, particularly preferably 5 to 45%. The content of these individual compounds is preferably in each case 2 to 20%. [0378] x) LC medium in which the proportion of compounds of the formulae CY, PY and ZK in the mixture as a whole is greater than 70%, preferably greater than 80%. [0379] y) LC medium in which the LC host mixture contains one or more compounds containing an alkenyl group, preferably selected from the group consisting of formula CY, PY and LY, wherein one or both of R.sup.1 and R.sup.2 denote straight-chain alkenyl having 2-6 C atoms, formula ZK and DK, wherein one or both of R.sup.3 and R.sup.4 or one or both of R.sup.5 and R.sup.6 denote straight-chain alkenyl having 2-6 C atoms, and formula B2 and B3, very preferably selected from formulae CY15, CY16, CY24, CY32, PY15, PY16, ZK3, ZK4, DK3, DK6, B2 and B3, most preferably selected from formulae ZK3, ZK4, B2 and B3. The concentration of these compounds in the LC host mixture is preferably from 2 to 70%, very preferably from 3 to 55%. [0380] z) LC medium which contains one or more, preferably 1 to 5, compounds selected of formula PY1-PY8, very preferably of formula PY2. The proportion of these compounds in the mixture as a whole is preferably 1 to 30%, particularly preferably 2 to 20%. The content of these individual compounds is preferably in each case 1 to 20%. [0381] z1) LC medium which contains one or more, preferably 1, 2 or 3, compounds of formula T2. The content of these compounds in the mixture as a whole is preferably 1 to 20%. [0382] z2) LC medium in which the LC host mixture contains one or more, preferably 1, 2 or 3, compounds of formula BF1, and one or more, preferably 1, 2 or 3, compounds selected from formulae AY14, AY15 and AY16, very preferably of formula AY14. The proportion of the compounds of formula AY14-AY16 in the LC host mixture is preferably from 2 to 35%, very preferably from 3 to 30%. The proportion of the compounds of formula BF1 in the LC host mixture is preferably from 0.5 to 20%, very preferably from 1 to 15%. Further preferably the LC host mixture according to this preferred embodiment contains one or more, preferably 1, 2 or 3 compounds of formula T, preferably selected from formula T1, T2 and T5, very preferably from formula T2 or T5. The proportion of the compounds of formula T in the LC host mixture medium is preferably from 0.5 to 15%, very preferably from 1 to 10%.

[0383] In a second preferred embodiment the LC medium contains an LC host mixture based on compounds with positive dielectric anisotropy. Such LC media are especially suitable for use in PS-OCB-, PS-TN-, PS-Posi-VA-, PS-IPS- or PS-FFS-displays.

[0384] Particularly preferred is an LC medium of this second preferred embodiment, which contains one or more compounds selected from the group consisting of compounds of formula AA and BB

##STR00098##

and optionally contains, in addition to the compounds of formula AA and/or BB, one or more compounds of formula CC

##STR00099##

in which the individual radicals have the following meanings:

##STR00100##

each, independently of one another, and on each occurrence, identically or differently

##STR00101##

each, independently of one another, and on each occurrence, identically or differently

##STR00102## [0385] R.sup.21, R.sup.31, R.sup.41, R.sup.42 each, independently of one another, alkyl, alkoxy, oxaalkyl or alkoxyalkyl having 1 to 9 C atoms or alkenyl or alkenyloxy having 2 to 9 C atoms, all of which are optionally fluorinated, [0386] X.sup.0 F, Cl, halogenated alkyl or alkoxy having 1 to 6 C atoms or halogenated alkenyl or alkenyloxy having 2 to 6 C atoms, [0387] Z.sup.31 —CH.sub.2CH.sub.2—, —CF.sub.2CF.sub.2—, —COO—, trans-CH═CH—, trans-CF═CF—, —CH.sub.2O— or a single bond, preferably —CH.sub.2CH.sub.2—, —COO—, trans-CH═CH— or a single bond, particularly preferably —COO—, trans-CH═CH— or a single bond, [0388] Z.sup.41, Z.sup.42 —CH.sub.2CH.sub.2—, —COO—, trans-CH═CH—, trans-CF═CF—, —CH.sub.2O—, —CF.sub.2O—, —C≡C— or a single bond, preferably a single bond, [0389] L.sup.21, L .sup.22, L.sup.31, L.sup.32 H or F, [0390] g 0, 1, 2 or 3, [0391] h 0, 1, 2 or 3.

[0392] X.sup.0 is 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 or CH═CF.sub.2, very preferably F or OCF.sub.3

[0393] The compounds of formula AA are preferably selected from the group consisting of the following formulae:

##STR00103##

in which A.sup.21, R.sup.21, X.sup.0, L.sup.21 and L.sup.22 have the meanings given in formula AA, L.sup.23 and L.sup.24 each, independently of one another, are H or F, and X.sup.0 is preferably F. Particularly preferred are compounds of formulae AA1 and AA2.

[0394] Particularly preferred compounds of formula AA1 are selected from the group consisting of the following subformulae:

##STR00104##

in which R.sup.21, X.sup.0, L.sup.21 and L.sup.22 have the meaning given in formula AA1, L.sup.23, L.sup.24, L.sup.25 and L.sup.26 are each, independently of one another, H or F, and X.sup.0 is preferably F.

[0395] Very particularly preferred compounds of formula AA1 are selected from the group consisting of the following subformulae:

##STR00105##

[0396] In which R.sup.21 is as defined in formula AA1.

[0397] Very preferred compounds of formula AA2 are selected from the group consisting of the following subformulae:

##STR00106## ##STR00107##

in which R.sup.21, X.sup.0, L.sup.21 and L.sup.22 have the meaning given in formula AA2, L.sup.23, L.sup.24, L.sup.25 and L.sup.26 each, independently of one another, are H or F, and X.sup.0 is preferably F.

[0398] Very particularly preferred compounds of formula AA2 are selected from the group consisting of the following subformulae:

##STR00108## ##STR00109##

in which R.sup.21 and X.sup.0 are as defined in formula AA2.

[0399] Particularly preferred compounds of formula AA3 are selected from the group consisting of the following subformulae:

##STR00110##

in which R.sup.21, X.sup.0, L.sup.21 and L.sup.22 have the meaning given in formula AA3, and X.sup.0 is preferably F.

[0400] Particularly preferred compounds of formula AA4 are selected from the group consisting of the following subformulae:

##STR00111##

in which R.sup.21 is as defined in formula AA4.

[0401] The compounds of formula BB are preferably selected from the group consisting of the following formulae:

##STR00112##

in which g, A.sup.31, A.sup.32, R.sup.31, X.sup.0, L.sup.31 and L.sup.32 have the meanings given in formula BB, and X.sup.0 is preferably F. Particularly preferred are compounds of formulae BB1 and BB2.

[0402] Particularly preferred compounds of formula BB1 are selected from the group consisting of the following subformulae:

##STR00113##

in which R.sup.31, X.sup.0, L.sup.31 and L.sup.32 have the meaning given in formula BB1, and X.sup.0 is preferably F.

[0403] Very particularly preferred compounds of formula BB1a are selected from the group consisting of the following subformulae:

##STR00114##

in which R.sup.31 is as defined in formula BB1.

[0404] Very particularly preferred compounds of formula BB1b are selected from the group consisting of the following subformulae:

##STR00115##

in which R.sup.31 is as defined in formula BB1.

[0405] Particularly preferred compounds of formula BB2 are selected from the group consisting of the following subformulae:

##STR00116## ##STR00117##

in which R.sup.31, X.sup.0, L.sup.31 and L.sup.32 have the meaning given in formula BB2, L.sup.33, L.sup.34, L.sup.35 and L.sup.36 are each, independently of one another, H or F, and X.sup.0 is preferably F.

[0406] Very particularly preferred compounds of formula BB2 are selected from the group consisting of the following subformulae:

##STR00118##