LIQUID CRYSTAL MIXTURE AND LIQUID CRYSTAL DISPLAY

Abstract

The invention relates to a compound of formula I,

##STR00001##

wherein R.sup.11, R.sup.21, A.sup.11, A, Z, X.sup.11, X.sup.21, Y.sup.11, Y.sup.12, Sp.sup.11, Sp.sup.21, o and p have one of the meanings as given in claim 1. The invention further relates to method of production of a compound of formula I, to the use of said compounds in LC media and to LC media comprising one or more compounds of formula I. Further, the invention relates to a method of production of such LC media, to the use of such media in LC devices, and to LC device comprising a LC medium according to the present invention. The present invention further relates to a process for the fabrication such liquid crystal display and to the use of the liquid crystal mixtures according to the invention for the fabrication of such liquid crystal display.

Claims

1. A compound of formula I, ##STR00404## wherein A.sup.11 denotes a radical selected from the following groups: a) a group consisting of 1,4-phenylene and 1,3-phenylene, wherein, in addition, one or two CH groups may be replaced by N and wherein, in addition, one or more H atoms may be replaced by L, b) a group selected from the group consisting of ##STR00405## where, in addition, one or more H atoms in these radicals may be replaced by L, and/or one or more double bonds may be replaced by single bonds, and/or one or more CH groups may be replaced by N, A have each, independently of one another, in each occurrence one of the meanings for A.sup.11 or a) group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, wherein, in addition, one or more non-adjacent CH.sub.2 groups may be replaced by —O— and/or —S— and wherein, in addition, one or more H atoms may be replaced by F, or b) a group consisting of tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, piperidine-1,4-diyl, thiophene-2,5-diyl and selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L, L on each occurrence, identically or differently, denotes —OH, —F, —Cl, —Br, —I, —CN, —NO.sub.2, SF.sub.5, —NCO, —NCS, —OCN, —SCN, —C(═O)N(R.sup.z).sub.2, —C(═O)R.sup.z, —N(R.sup.z).sub.2, optionally substituted silyl, optionally substituted aryl having 6 to 20 C atoms, or straight-chain alkyl having 1 to 25 C atoms or branched alkyl having 3 to 25 C atoms or cyclic alkyl having 3 to 25 C atoms, alkoxy having 1 to 25 C atoms, alkylcarbonyl having 2 to 25 C atoms, alkoxycarbonyl having 2 to 25 C atoms, alkylcarbonyloxy having 2 to 25 C atoms or alkoxycarbonyloxy having 2 to 25 C atoms, in which, in addition, one or more H atoms may be replaced by F or Cl, or X.sup.21-Sp.sup.21-R.sup.21, M denotes —O—, —S—, —CH.sub.2—, —CHR.sup.z— or —CR.sup.yR.sup.z—, and R.sup.y and R.sup.z each, independently of one another, denote H, CN, F or alkyl having 1-12 C atoms, wherein one or more H atoms may be replaced by F, Y.sup.11 and Y.sup.12 each, independently of one another, denote H, F, phenyl or alkyl having 1-12 C atoms, wherein one or more H atoms may be replaced by F, Z denotes, independently of each other, in each occurrence, a single bond, —COO—, —OCO—, —O—CO—O—, —OCH.sub.2—, —CH.sub.2O—, —OCF.sub.2—, —CF.sub.2O—, oder —(CH.sub.2).sub.n— —(CH.sub.2).sub.n— wherein one or more non-adjacent groups may be replaced by O or S, —CF.sub.2CF.sub.2—, —CH═CH—, —CF═CF—, —CH═CH—COO—, —OCO—CH═CH—, —CO—S—, —S—CO—, —CS—S—, —S—CS—, —S—CSS— or —C≡C—, n denotes an integer between 2 and 8, and p denote each and independently 0, 1 or 2, X.sup.11 and X.sup.21 denote independently from one another, in each occurrence a single bond, —CO—O—, —O—CO—, —O—COO—, —O—, —CH═CH—, —C≡C—, —CF.sub.2—O—, —O—CF.sub.2—, —CF.sub.2—CF.sub.2—, —CH.sub.2—O—, —O—CH.sub.2—, —CO—S—, —S—CO—, —CS—S—, —S—CS—, —S—CSS— or —S—, Sp.sup.11 and Sp.sup.21 denote each and independently, in each occurrence a single bond or a spacer group comprising 1 to 20 C atoms, wherein one or more non-adjacent and non-terminal CH.sub.2 groups may also be replaced by —O—, —S—, —NH—, —N(CH.sub.3)—, —CO—, —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O—, —CF.sub.2—, —CF.sub.2O—, —OCF.sub.2— —C(OH)—, —CH(alkyl)-, —CH(alkenyl)-, —CH(alkoxyl)-, —CH(oxaalkyl)-, —CH═CH— or —C≡C—, however in such a way that no two O— atoms are adjacent to one another and no two groups selected from —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O— and —CH═CH— are adjacent to each other, R.sup.11 and R.sup.21 denotes P.sup.11, P.sup.21, halogen, CN, or optionally fluorinated alkyl or alkenyl with up to 15 C atoms in which one or more non-adjacent CH.sub.2-groups may be replaced by —O—, —S—, —CO—, —C(O)O—, —O—C(O)—, O—C(O)—O—, under the condition that at least one of R.sup.11 and R.sup.21 denotes P.sup.21, P.sup.11 each and independently from another in each occurrence a polymerizable group, P.sup.21 denotes a group ##STR00406## Y denotes H, F, phenyl or optionally fluorinated alkyl having 1-12 C atoms, q and r denotes each and independently an integer from 0 to 8.

2. A compound according to claim 1, which is selected from compounds of the sub-formulae I-1 to I-9. ##STR00407## wherein R.sup.11, R.sup.21, A.sup.11, X.sup.11, X.sup.12, Y.sup.11, Y.sup.12, Sp.sup.11, and Sp.sup.12 have in each occurrence and each and independently from another one of the meanings as given in claim 1, A.sup.12 to A.sup.23 have each and independently from another one of the meanings for A as given in claim 1, and Z.sup.11 to Z.sup.22 have each and independently from another one of the meanings for Z as given in claim 1.

3. A compound according to claim 1, which is selected from the following compounds of formulae I-1a to I-4c. ##STR00408## wherein L, R.sup.11, R.sup.21, A.sup.11, X.sup.11, X.sup.21, Y.sup.11, Y.sup.12, Sp.sup.11, and Sp.sup.21 have one of the meanings as given in formula I, A.sup.12 to A.sup.23 have one of the meanings for A in formula I, and Z.sup.11 to Z.sup.22 have one of the meanings for Z as given in formula I.

4. A compound according to claim 1, which is selected from compounds of the following sub-formulae ##STR00409## wherein L, R.sup.11, R.sup.21, A.sup.11, X.sup.11, X.sup.21, Sp.sup.11, and Sp.sup.21 have one of the meanings as given formula I, A.sup.12 and A.sup.22 have one of the meanings for A in formula I, and Z.sup.11 and Z.sup.22 have one of the meanings for Z as given in formula I.

5. A compound according to claim 1, which is selected from compounds of the sub-formulae ##STR00410## ##STR00411## wherein Sp.sup.11 and Sp.sup.21 have one of the meanings as given in formula I, and Y denotes methyl or ethyl.

6. A method comprising including a compound of formula I of claim 1 in a liquid crystal mixture.

7. A Liquid crystal mixture, which comprises a component A) comprising one or more compounds of formula I according to claim 1, and a liquid-crystalline component B), comprising one or more mesogenic or liquid-crystalline compounds.

8. A Liquid crystal mixture according to claim 7, wherein the total concentration of compounds of formula I in the mixture is in the range of from 0.01 to 10% by weight.

9. A Liquid crystal mixture according to claim 7, which additionally comprises a polymerizable component C) comprising one or more polymerizable mesogenic or polymerizable isotropic compounds.

10. A Liquid crystal mixture according to claim 9, wherein the concentration of polymerizable mesogenic or polymerizable isotropic compounds is in the range of from 0.01 to 10% by weight.

11. A Liquid crystal mixture according to claim 7, wherein the LC host mixture has negative dielectric anisotropy.

12. Liquid crystal mixture according to claim 11, wherein the LC host mixture comprises one or more compounds selected from the following formulae: ##STR00412## wherein a is 1 or 2, b is 0 or 1, ##STR00413## denotes ##STR00414## 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.

13. A Liquid crystal mixture according to claim 7, wherein the LC host mixture has positive dielectric anisotropy.

14. A Liquid crystal mixture according to claim 13, wherein the LC host mixture comprises one or more compounds selected from the group consisting of the compounds of the formulae II and III, ##STR00415## wherein R.sup.20 each, identically or differently, denote a halogenated or unsubstituted alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by —C≡C—, —CF.sub.2O—, —CH═CH—, ##STR00416##  —O—, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another, X.sup.20 each, identically or differently, denote F, Cl, CN, SF.sub.5, SCN, NCS, a halogenated alkyl radical, a halogenated alkenyl radical, a halogenated alkoxy radical or a halogenated alkenyloxy radical, each having up to 6 C atoms, and Y.sup.20-24 each, identically or differently, denote H or F, W denotes H or methyl, ##STR00417## each, identically or differently, denote ##STR00418##

15. A Liquid crystal mixture according to claim 13, which comprises one or more compounds selected from the group consisting of compounds of formulae XI and XII ##STR00419## wherein R.sup.20, X.sup.20, W and Y.sup.20-23 have the meanings indicated in formula III, and ##STR00420## each, independently of one another, denote ##STR00421## ##STR00422## denotes H ##STR00423##

16. A Liquid crystal mixture according to claim 7, wherein the LC host mixture comprises one or more compounds of the following formula: ##STR00424## in which the individual radicals have the following meanings: ##STR00425## denotes ##STR00426## ##STR00427## denotes H or O ##STR00428## 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—, —CO—O—, —O—CO—, —C.sub.2F.sub.4—, —CF═CF—, —CH═CH—CH.sub.2O— or a single bond.

17. A Liquid crystal mixture according to claim 7, wherein the LC host mixture comprises one or more compounds of the following formula ##STR00429## wherein the propyl, butyl and pentyl groups are straight-chain groups.

18. A Liquid crystal mixture according to claim 7, wherein the LC host mixture comprises one or more compounds selected from the following formulae: ##STR00430## 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.

19. A Liquid crystal mixture according to claim 7, wherein the LC host mixture comprises one or more compounds selected from the following formulae: ##STR00431## in which alkyl* denotes an alkyl radical having 1-6 C atoms.

20. A method for fabricating a liquid crystal display comprising incorporating a liquid crystal mixture according to claim 7.

21. A process for the fabrication of a liquid crystal display, comprising at least the steps of: providing a first substrate which includes a pixel electrode and a common electrode for generating an electric field substantially parallel to a surface of the first substrate in the pixel region; providing a second substrate, the second substrate being disposed opposite to the first substrate; interposing a liquid crystal mixture according to claim 7; irradiating the liquid crystal mixture with linearly polarised light causing photoalignment of the liquid crystal; curing the polymerizable compounds of the liquid crystal mixture by irradiation with ultraviolet light or visible light having a wavelength of 450 nm or below.

22. A process according to claim 21, wherein the linearly polarised light is ultraviolet light or visible light having a wavelength of 450 nm or below.

23. A display, obtainable by a process according to claim 21.

24. A display according to claim 23, wherein the LC host mixture is homogeneously aligned without the application of an electric field.

25. A display according to claim 23, wherein the display is an IPS or FFS display.

Description

DETAILED DESCRIPTION

[0077] In detail, the present invention relates to compounds or photoreactive mesogens of formula I,

##STR00017##

wherein [0078] A.sup.11 denotes a radical selected from the following groups: [0079] a) a group consisting of 1,4-phenylene and 1,3-phenylene, wherein, in addition, one or two CH groups may be replaced by N and wherein, in addition, one or more H atoms may be replaced by L, [0080] b) a group selected from the group consisting of

##STR00018## [0081] where, in addition, one or more H atoms in these radicals may be replaced by L, and/or one or more double bonds may be replaced by single bonds, and/or one or more CH groups may be replaced by N, [0082] A have each, independently of one another, in each occurrence one of the meanings for A.sup.11 or [0083] a) group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, wherein, in addition, one or more non-adjacent CH.sub.2 groups may be replaced by —O— and/or —S— and wherein, in addition, one or more H atoms may be replaced by F, or [0084] b) a group consisting of tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, piperidine-1,4-diyl, thiophene-2,5-diyl and selenophene-2,5-diyl, [0085] each of which may also be mono- or polysubstituted by L, [0086] L on each occurrence, identically or differently, denotes —OH, —F, —Cl, —Br, —I, —CN, —NO.sub.2, SF.sub.5, —NCO, —NCS, —OCN, —SCN, —C(═O)N(R.sup.z).sub.2, —C(═O)R.sup.z, —N(R.sup.z).sub.2, optionally substituted silyl, optionally substituted aryl having 6 to 20 C atoms, or straight-chain or branched or cyclic alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, preferably 1 to 12 C atoms, more preferably 1 to 6 C atoms, in which, in addition, one or more H atoms may be replaced by F or Cl, or X.sup.21—Sp.sup.21-R.sup.21, [0087] M denotes —O—, —S—, —CH.sub.2—, —CHR.sup.z— or —CR.sup.yR.sup.z—, and [0088] R.sup.y and R.sup.z each, independently of one another, denote H, CN, F or alkyl having 1-12 C atoms, wherein one or more H atoms may be replaced by F, [0089] preferably H, methyl, ethyl, propyl, butyl, [0090] more preferably H or methyl, [0091] in particular H, [0092] Y.sup.11 and Y.sup.12 each, independently of one another, denote H, F, phenyl or optionally fluorinated alkyl having 1-12 C atoms, wherein one or more H atoms may be replaced by F, [0093] preferably H, methyl, ethyl, propyl, butyl, [0094] more preferably H or methyl, [0095] in particular H, [0096] Z denotes, independently of each other, in each occurrence, a single bond, —COO—, —OCO—, —O—CO—O—, —OCH.sub.2—, —CH.sub.2O—, —OCF.sub.2—, —CF.sub.2O—, —(CH.sub.2).sub.n— wherein one or more non-adjacent groups may be replaced by O or S, —CF.sub.2CF.sub.2—, —CH═CH—, —CF═CF—, —CH═CH—COO—, —OCO—CH═CH—, —CO—S—, —S—CO—, —CS—S—, —S—CS—, —S—CSS— or —C≡C—, [0097] preferably a single bond, —COO—, —OCO—, —OCF.sub.2—, —CF.sub.2O—, or —(CH.sub.2).sub.n—, [0098] more preferably a single bond, —COO—, or —OCO—, [0099] n denotes an integer between 2 and 8, preferably 2, [0100] and p denote each and independently 0, 1 or 2, preferably 1, [0101] X.sup.11 and X.sup.21 denote independently from one another, in each occurrence a single bond, —CO—O—, —O—CO—, —O—COO—, —O—, —CH═CH—, —C≡C—, —CF.sub.2—O—, —O—CF.sub.2—, —CF.sub.2—CF.sub.2—, —CH.sub.2—O—, —O—CH.sub.2—, —CO—S—, —S—CO—, —CS—S—, —S—CS—, —S—CSS— or —S—, [0102] preferably, a single bond —CO—O—, —O—CO—, —O—COO—, or —O—, [0103] more preferably a single bond or —O—, [0104] Sp.sup.11 and Sp.sup.21 denote each and independently, in each occurrence a single bond or a spacer group comprising 1 to 20 C atoms, preferably 2 to 20 C atoms, wherein one or more non-adjacent and non-terminal CH.sub.2 groups may also be replaced by —O—, —S—, —NH—, —N(CH.sub.3)—, —CO—, —OCO—, —S—CO—, —O—COO—, —CO—S—, —CO—O—, —CF.sub.2—, —CF.sub.2O—, —OCF.sub.2— —C(OH)—, —CH(alkyl)-, —CH(alkenyl)-, —CH(alkoxyl)-, —CH(oxaalkyl)-, —CH═CH— or —C≡C—, however in such a way that no two O-atoms are adjacent to one another and no two groups selected from —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O— and —CH═CH— are adjacent to each other, [0105] preferably alkylene having 1 to 20, preferably 1 to 12, C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN, [0106] more preferably straight-chain ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, [0107] R.sup.11 and R.sup.21 denotes P.sup.11, P.sup.21, halogen, CN, or optionally fluorinated alkyl or alkenyl with up to 15 C atoms in which one or more non-adjacent CH.sub.2-groups may be replaced by —O—, —S—, —CO—, —C(O)O—, —O—C(O)—, O—C(O)—O—, under the condition that at least one of R.sup.11 and R.sup.21 denotes P.sup.21, more preferably both P.sup.21, [0108] P.sup.11 each and independently from another in each occurrence a polymerizable group, [0109] P.sup.21 denotes a group

##STR00019## [0110] preferably a group

##STR00020## [0111] Y denotes H, F, phenyl or optionally fluorinated alkyl having 1-12 C atoms, preferably H, methyl, ethyl, propyl, butyl, [0112] more preferably H, methyl ethyl or propyl, [0113] in particular H, methyl, or ethyl, especially methyl or ethyl, [0114] q and r denotes each and independently an integer from 0 to 8, preferably q+r≥1 and ≤16, more preferably q and r each and independently denotes an integer from 1 to 8.

[0115] Further preferred are compounds of formula I, wherein [0116] Sp.sup.21 denotes a spacer group comprising 1 to 20 C atoms, preferably 2 to 20 C atoms, wherein one or more non-adjacent and non-terminal CH.sub.2 groups may also be replaced by —O—, —S—, —NH—, —N(CH.sub.3)—, —CO—, —O—CO—, —SCO—, —O—COO—, —CO—S—, —CO—O—, —CF.sub.2—, —CF.sub.2O—, —OCF.sub.2— —C(OH)—, —CH(alkyl)-, —CH(alkenyl)-, —CH(alkoxyl)-, —CH(oxaalkyl)-, —CH═CH— or —C≡C—, however in such a way that no two O-atoms are adjacent to one another and no two groups selected from —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O— and —CH═CH— are adjacent to each other, if X.sup.21 denotes single bond and if at the same time R.sup.11 denotes P.sup.21 and Y denotes H.

[0117] Further preferred are compounds of formula I, wherein [0118] Sp.sup.21 denotes a spacer group comprising 2 to 20 C atoms, wherein one or more non-adjacent and non-terminal CH.sub.2 groups may also be replaced by —O—, —S—, —NH—, —N(CH.sub.3)—, —CO—, —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O—, —CF.sub.2—, —CF.sub.2O—, —OCF.sub.2— —C(OH)—, —CH(alkyl)-, —CH(alkenyl)-, —CH(alkoxyl)-, —CH(oxaalkyl)-, —CH═CH— or —C≡C—, however in such a way that no two O-atoms are adjacent to one another and no two groups selected from —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O— and —CH═CH— are adjacent to each other, if X.sup.21 denotes —O— and if at the same time R.sup.11 denotes P.sup.21 and Y denotes H.

[0119] In the instant application, polymerizable groups (P) are groups that are suitable for a polymerisation reaction, such as, for example, free-radical or ionic chain polymerisation, polyaddition or polycondensation, or for a polymer-analogous reaction, for example addition or condensation onto a main polymer chain. Particular preference is given to groups for chain polymerisation, in particular those containing a C═C double bond or —C≡C— triple bond, and groups which are suitable for polymerisation with ring opening, such as, for example, oxetane or epoxide groups.

[0120] Preferred groups P.sup.11 are selected from the group consisting of CH.sub.2═CW.sup.1—CO—O—, CH.sub.2═CW.sup.1—CO—,

##STR00021##

CH.sub.2═CW.sup.2—(O).sub.k3—, CW.sup.1═CH—CO—(O).sub.k3—, CW.sup.1═CH—CO—NH—, CH.sub.2═CW.sup.1—CO—NH—, CH.sub.3—CH═CH—O—, (CH.sub.2═CH).sub.2CH—OCO—, (CH.sub.2═CH—CH.sub.2).sub.2CH—OCO—, (CH.sub.2═CH).sub.2CH—O—, (CH.sub.2═CH—CH.sub.2).sub.2N—, (CH.sub.2═CH—CH.sub.2).sub.2N—CO—, HO—CW.sup.2W.sup.3—, HS—CW.sup.2W.sup.3—, HW.sup.2N—, HO—CW.sup.2W.sup.3—NH—, CH.sub.2═CW.sup.1—CO—NH—, CH.sub.2═CH—(COO).sub.k1-Phe-(O).sub.k2—, CH.sub.2═CH—(CO).sub.k1-Phe-(O).sub.k2—, Phe-CH═CH—, HOOC—, OCN— and W.sup.4W.sup.5W.sup.6Si—, wherein W.sup.1 denotes H, F, Cl, CN, CF.sub.3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH.sub.3, W.sup.2 and W.sup.3 each, independently of one another, denote H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W.sup.4, W.sup.5 and W.sup.6 each, independently of one another, denote Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W.sup.7 and W.sup.8 each, independently of one another, denote H, Cl or alkyl having 1 to 5 C atoms, Phe denotes 1,4-phenylene, which is optionally substituted by one or more radicals L as defined above which are other than P-Sp-, k.sub.1, k.sub.2 and k.sub.3 each, independently of one another, denote 0 or 1, k.sub.3 preferably denotes 1, and k.sub.4 denotes an integer from 1 to 10.

[0121] Particularly preferred groups P.sup.11 are selected from the group consisting of CH.sub.2═CW.sup.1—CO—O—, in particular CH.sub.2═CH—CO—O—, CH.sub.2═C(CH.sub.3)—CO—O— and CH.sub.2═CF—CO—O—, furthermore CH.sub.2═CH—O—, (CH.sub.2═CH).sub.2CH—O—CO—, (CH.sub.2═CH).sub.2CH—O—,

##STR00022##

[0122] Very particularly preferred groups P.sup.1 are selected from the group consisting of acrylate, methacrylate, fluoroacrylate, furthermore vinyloxy, chloroacrylate, oxetane and epoxide groups, and of these preferably an acrylate or methacrylate group.

[0123] The compounds of formula I are preferably selected from compounds of the sub-formulae I-1 to I-9,

##STR00023##

wherein R.sup.11, R.sup.21, A.sup.11, X.sup.11, X.sup.21, Y.sup.11, Y.sup.12, Sp.sup.11, and Sp.sup.21 have one of the meanings as given above in formula I, A.sup.12 to A.sup.23 have one of the meanings for A in formula I, and Z.sup.11 to Z.sup.22 have one of the meanings for Z as given above under formula I.

[0124] Further preferred are compounds of formula I-1, wherein [0125] Sp.sup.21 denotes a spacer group comprising 1 to 20 C atoms, preferably 2 to 20 C atoms, wherein one or more non-adjacent and non-terminal CH.sub.2 groups may also be replaced by —O—, —S—, —NH—, —N(CH.sub.3)—, —CO—, —O—CO—, —SCO—, —O—COO—, —CO—S—, —CO—O—, —CF.sub.2—, —CF.sub.2O—, —OCF.sub.2— —C(OH)—, —CH(alkyl)-, —CH(alkenyl)-, —CH(alkoxyl)-, —CH(oxaalkyl)-, —CH═CH— or —C≡C—, however in such a way that no two O-atoms are adjacent to one another and no two groups selected from —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O— and —CH═CH— are adjacent to each other, if X.sup.21 denotes single bond and if at the same time R.sup.21 denotes P.sup.21 and Y denotes H.

[0126] Further preferred are compounds of formula I, wherein [0127] Sp.sup.21 denotes a spacer group comprising 2 to 20 C atoms, wherein one or more non-adjacent and non-terminal CH.sub.2 groups may also be replaced by —O—, —S—, —NH—, —N(CH.sub.3)—, —CO—, —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O—, —CF.sub.2—, —CF.sub.2O—, —OCF.sub.2— —C(OH)—, —CH(alkyl)-, —CH(alkenyl)-, —CH(alkoxyl)-, —CH(oxaalkyl)-, —CH═CH— or —C≡C—, however in such a way that no two O-atoms are adjacent to one another and no two groups selected from —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O— and —CH═CH— are adjacent to each other, if X.sup.21 denotes —O— and if at the same time R.sup.21 denotes P.sup.21 and Y denotes H.

[0128] Further preferred compounds of formula I are selected from the following compounds of formulae I-1a to I-4c.

##STR00024## ##STR00025##

wherein L, R.sup.11, R.sup.21, A.sup.11, X.sup.11, X.sup.21, Y.sup.11, Y.sup.12, Sp.sup.11, and Sp.sup.21 have one of the meanings as given above in formula I, A.sup.12 to A.sup.23 have one of the meanings for A in formula I, and Z.sup.11 to Z.sup.22 have one of the meanings for Z as given above under formula I.

[0129] Further preferred are compounds of formula I-1a, wherein [0130] Sp.sup.21 denotes a spacer group comprising 1 to 20 C atoms, preferably 2 to 20 C atoms, wherein one or more non-adjacent and non-terminal CH.sub.2 groups may also be replaced by —O—, —S—, —NH—, —N(CH.sub.3)—, —CO—, —O—CO—, —SCO—, —O—COO—, —CO—S—, —CO—O—, —CF.sub.2—, —CF.sub.2O—, —OCF.sub.2— —C(OH)—, —CH(alkyl)-, —CH(alkenyl)-, —CH(alkoxyl)-, —CH(oxaalkyl)-, —CH═CH— or —C≡C—, however in such a way that no two O-atoms are adjacent to one another and no two groups selected from —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O— and —CH═CH— are adjacent to each other, if X.sup.21 denotes single bond and if at the same time R.sup.21 denotes P.sup.21 and Y denotes H.

[0131] Further preferred are compounds of formula I, wherein [0132] Sp.sup.21 denotes a spacer group comprising 2 to 20 C atoms, wherein one or more non-adjacent and non-terminal CH.sub.2 groups may also be replaced by —O—, —S—, —NH—, —N(CH.sub.3)—, —CO—, —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O—, —CF.sub.2—, —CF.sub.2O—, —OCF.sub.2— —C(OH)—, —CH(alkyl)-, —CH(alkenyl)-, —CH(alkoxyl)-, —CH(oxaalkyl)-, —CH═CH— or —C≡C—, however in such a way that no two O-atoms are adjacent to one another and no two groups selected from —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O— and —CH═CH— are adjacent to each other, if X.sup.21 denotes —O— and if at the same time R.sup.21 denotes P.sup.21 and Y denotes H.

[0133] Further preferred compounds of formula I are selected from the following compounds:

##STR00026## ##STR00027##

wherein L, R.sup.11, R.sup.21, A.sup.11, X.sup.11, X.sup.21, Sp.sup.11, and Sp.sup.21 have one of the meanings as given above in formula I, A.sup.12 and A.sup.22 have one of the meanings for A in formula I, and Z.sup.11 and Z.sup.22 have one of the meanings for Z as given above under formula I.

[0134] Further preferred are compounds of formula I-1a-1, wherein [0135] Sp.sup.21 denotes a spacer group comprising 1 to 20 C atoms, preferably 2 to 20 C atoms, wherein one or more non-adjacent and non-terminal CH.sub.2 groups may also be replaced by —O—, —S—, —NH—, —N(CH.sub.3)—, —CO—, —O—CO—, —SCO—, —O—COO—, —CO—S—, —CO—O—, —CF.sub.2—, —CF.sub.2O—, —OCF.sub.2— —C(OH)—, —CH(alkyl)-, —CH(alkenyl)-, —CH(alkoxyl)-, —CH(oxaalkyl)-, —CH═CH— or —C≡C—, however in such a way that no two O-atoms are adjacent to one another and no two groups selected from —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O— and —CH═CH— are adjacent to each other, if X.sup.21 denotes single bond and if at the same time R.sup.21 denotes P.sup.21 and Y denotes H.

[0136] Further preferred are compounds of formula I, wherein [0137] Sp.sup.21 denotes a spacer group comprising 2 to 20 C atoms, wherein one or more non-adjacent and non-terminal CH.sub.2 groups may also be replaced by —O—, —S—, —NH—, —N(CH.sub.3)—, —CO—, —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O—, —CF.sub.2—, —CF.sub.2O—, —OCF.sub.2— —C(OH)—, —CH(alkyl)-, —CH(alkenyl)-, —CH(alkoxyl)-, —CH(oxaalkyl)-, —CH═CH— or —C≡C—, however in such a way that no two O-atoms are adjacent to one another and no two groups selected from —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O— and —CH═CH— are adjacent to each other, if X.sup.21 denotes —O— and if at the same time R.sup.21 denotes P.sup.21 and Y denotes H.

[0138] Further preferred compounds of formula I-2a-1 to I-3b-2 are selected from the following compounds:

##STR00028##

wherein L, R.sup.11, R.sup.21, X.sup.11, X.sup.21, Sp.sup.11, and Sp.sup.12 have one of the meanings as given above in formula I, and
the group

##STR00029##

is each and independently

##STR00030##

or denotes

##STR00031##

furthermore

##STR00032##

wherein L have one of the meanings as given above in formula I, and preferably denotes F, Cl, OCH.sub.3, COCH.sub.3 or alkyl having 1 to 6 C Atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, or X.sup.21—Sp.sup.21-R.sup.21.

[0139] Further preferred compound of formula I and subformulae thereof are selected from compounds wherein the groups —X.sup.11—Sp.sup.11-R.sup.11 and X.sup.21-Sp.sup.21-R.sup.21 are selected from different groups, such as

[0140] —X.sup.11-Sp.sup.11-P.sup.11 and —X.sup.21-Sp.sup.21-P.sup.21

[0141] —X.sup.11-Sp.sup.11-P.sup.21 and —X.sup.21-Sp.sup.21-P.sup.11,

[0142] —P.sup.11 and —X.sup.21-Sp.sup.21-P.sup.21, or

[0143] —X.sup.11-Sp.sup.11-P.sup.21 and —P.sup.11.

[0144] However it is likewise preferred that the groups —X.sup.11—Sp.sup.11-R.sup.11 and X.sup.21-Sp.sup.21-R.sup.21 are identical, such as —X.sup.11—Sp.sup.11-P.sup.21 and —X.sup.21-Sp.sup.21-P.sup.21.

[0145] Especially preferred compounds of formula I are selected from compounds of the following sub-formula:

##STR00033## ##STR00034## ##STR00035## ##STR00036##

wherein Sp.sup.11 and Sp.sup.21 have one of the meanings as given above in formula I, and Y denotes methyl or ethyl.

[0146] Preferred intermediate compounds (6) from which the compounds of formula I are preferably synthesised, are obtainable or obtained according to or in analogy to the procedure described in the following scheme:

##STR00037##

[0147] The compounds of formula I are prepared by methods known per se, as described in the literature (for example in the standard works, such as Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart), to be precise under reaction conditions which are known and suitable for the said reactions. Use can also be made here of variants known per se, which are not mentioned here in greater detail.

[0148] Preferably the compounds of formula I are synthesised, are obtainable or obtained according to or in analogy to the procedure described in the following scheme:

##STR00038##

[0149] The compounds of formula I and subformulae thereof can be preferably utilized in a mixture comprising one or more mesogenic or liquid-crystalline compounds.

[0150] Therefore, the present invention relates to the use compounds of formula I and subformulae thereof in a liquid crystal mixture.

[0151] Further the present invention relates to liquid crystal mixtures comprising a photoalignment component A) comprising one or more photoreactive mesogens of formula I, and a liquid-crystalline component B), hereinafter also referred to as “LC host mixture”, comprising one or more mesogenic or liquid-crystalline compounds.

[0152] The media according to the invention preferably comprise from 0.01 to 10%, particularly preferably from 0.05 to 5% and most preferably from 0.1 to 3% of component A) comprising compounds of formula I according to the invention.

[0153] The media preferably comprise one, two or three, more preferably one or two and most preferably one compound of the formula I according to the invention.

[0154] In a preferred embodiment component A) consists of compounds of formula I.

[0155] In a preferred embodiment, the LC-host mixture (component B) according to the present invention comprises one or more, preferably two or more, low-molecular-weight (i.e. monomeric or unpolymerized) compounds. The latter are stable or unreactive with respect to a polymerisation reaction or photoalignment under the conditions used for the polymerisation of the polymerizable compounds or photoalignment of the photoreactive mesogen of formula I.

[0156] In principle, a suitable host mixture is any dielectrically negative or positive LC mixture which is suitable for use in conventional VA, IPS or FFS displays.

[0157] Suitable LC mixtures are known to the person skilled in the art and are described in the literature. LC media for VA displays having negative dielectric anisotropy are described in for example EP 1 378 557 A1.

[0158] Suitable LC mixtures having positive dielectric anisotropy which are suitable for LCDs and especially for IPS displays are known, for example, from JP 07-181 439 (A), EP 0 667 555, EP 0 673 986, DE 195 09 410, DE 195 28 106, DE 195 28 107, WO 96/23 851, WO 96/28 521 and WO2012/079676.

[0159] Preferred embodiments of the liquid-crystalline medium having negative or positive dielectric anisotropy according to the invention are indicated below and explained in more detail by means of the working examples.

[0160] The LC host mixture is preferably a nematic LC mixture, and preferably does not have a chiral LC phase.

[0161] In a preferred embodiment of the present invention the LC medium contains an LC host mixture with negative dielectric anisotropy. Preferred embodiments of such an LC medium, and the corresponding LC host mixture, are those of sections a)-z) below: [0162] a) LC medium which comprises one or more compounds of the formulae CY and/or PY:

##STR00039## [0163] wherein [0164] a denotes 1 or 2, [0165] b denotes 0 or 1,

##STR00040##

denotes

##STR00041## [0166] 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, [0167] Z.sup.x and Z.sup.y each, independently of one another, [0168] 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, [0169] 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. [0170] 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. [0171] The compounds of the formula CY are preferably selected from the group consisting of the following sub-formulae:

##STR00042## ##STR00043## ##STR00044## ##STR00045## [0172] wherein 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—. [0173] The compounds of the formula PY are preferably selected from the group consisting of the following sub-formulae:

##STR00046## ##STR00047## ##STR00048## [0174] wherein 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 (0) 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—. [0175] b) LC medium which additionally comprises one or more compounds of the following formula:

##STR00049## [0176] in which the individual radicals have the following meanings:

##STR00050##

denotes

##STR00051##

denotes H or O

##STR00052## [0177] 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, [0178] 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.

[0179] The compounds of the formula ZK are preferably selected from the group consisting of the following sub-formulae:

##STR00053## [0180] 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—. [0181] Especially preferred are compounds of formula ZK1 and ZK3. [0182] Particularly preferred compounds of formula ZK are selected from the following sub-formulae:

##STR00054## [0183] wherein the propyl, butyl and pentyl groups are straight-chain groups. [0184] Most preferred are compounds of formula ZK1a and ZK3a. [0185] c) LC medium which additionally comprises one or more compounds of the following formula:

##STR00055## [0186] in which the individual radicals on each occurrence, identically or differently, have the following meanings: [0187] 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,

##STR00056##

denotes

##STR00057##

denotes

##STR00058##

and [0188] e denotes 1 or 2. [0189] The compounds of the formula DK are preferably selected from the group consisting of the following sub-formulae:

##STR00059## ##STR00060## [0190] 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—. [0191] d) LC medium which additionally comprises one or more compounds of the following formula:

##STR00061## [0192] in which the individual radicals have the following meanings:

##STR00062##

denotes

##STR00063## [0193] with at least one ring F being different from cyclohexylene, [0194] f denotes 1 or 2, [0195] 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, [0196] 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, [0197] 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. [0198] 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. [0199] The compounds of the formula LY are preferably selected from the group consisting of the following sub-formulae:

##STR00064## ##STR00065## ##STR00066## [0200] 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 oxy-gen 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—. [0201] e) LC medium which additionally comprises one or more compounds selected from the group consisting of the following formulae:

##STR00067## [0202] 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. [0203] f) LC medium which additionally comprises one or more compounds selected from the group consisting of the following formulae:

##STR00068## ##STR00069## [0204] 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. [0205] g) LC medium which additionally comprises one or more biphenyl compounds selected from the group consisting of the following formulae:

##STR00070## [0206] 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—. [0207] 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. [0208] The compounds of the formula B2 are particularly preferred. [0209] The compounds of the formulae B1 to B3 are preferably selected from the group consisting of the following sub-formulae:

##STR00071## [0210] 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 B2e. [0211] h) LC medium which additionally comprises one or more terphenyl compounds of the following formula:

##STR00072## [0212] in which R.sup.5 and R.sup.6 each, independently of one another, have one of the meanings indicated above, and

##STR00073## [0213] each, independently of one another, denote

##STR00074## [0214] 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. [0215] The compounds of the formula T are preferably selected from the group consisting of the following sub-formulae:

##STR00075## ##STR00076## ##STR00077## [0216] 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—. [0217] R preferably denotes methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy or pentoxy. [0218] 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. [0219] 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. [0220] 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. [0221] i) LC medium which additionally comprises one or more compounds selected from the group consisting of the following formulae:

##STR00078## [0222] 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. [0223] Preferred media comprise one or more compounds selected from the formulae 01, 03 and 04. [0224] k) LC medium which additionally comprises one or more compounds of the following formula:

##STR00079## [0225] in which

##STR00080##

denotes

##STR00081## [0226] 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. [0227] Particularly preferred compounds of the formula FI are selected from the group consisting of the following sub-formulae:

##STR00082## [0228] 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. [0229] l) LC medium which additionally comprises one or more compounds selected from the group consisting of the following formulae:

##STR00083## [0230] 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. [0231] m) 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:

##STR00084## ##STR00085## [0232] in which [0233] 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 O atoms are not linked directly to one another, preferably alkyl or alkoxy having 1 to 6 C atoms, [0234] and R.sup.10 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 [0235] Z.sup.1 and Z.sup.2 each, independently of one another, [0236] 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—, —COO—, —OCO—, —C.sub.2F.sub.4—, —CF═CF—, —CF═CH—, —CH═CF—, —CH.sub.2— or a single bond. [0237] n) LC medium which additionally comprises one or more difluoro-dibenzochromans and/or chromans of the following formulae:

##STR00086## [0238] in which [0239] R.sup.11 and R.sup.12 each, independently of one another, have one of the meanings indicated above for R.sup.11 under formula N1 [0240] ring M is trans-1,4-cyclohexylene or 1,4-phenylene, [0241] Z.sup.m —C.sub.2H.sub.4—, —CH.sub.2O—, —OCH.sub.2—, —CO—O— or —O—CO—, [0242] c is 0, 1 or 2, [0243] preferably in amounts of 3 to 20% by weight, in particular in amounts of 3 to 15% by weight. [0244] Particularly preferred compounds of the formulae BC, CR and RC are selected from the group consisting of the following sub-formulae:

##STR00087## ##STR00088## [0245] 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—. [0246] Very particular preference is given to mixtures comprising one, two or three compounds of the formula BC-2. [0247] o) LC medium which additionally comprises one or more fluorinated phenanthrenes and/or dibenzofurans of the following formulae:

##STR00089## [0248] 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 under formula N1, b denotes 0 or 1, L denotes F, and r denotes 1, 2 or 3. [0249] Particularly preferred compounds of the formulae PH and BF are selected from the group consisting of the following sub-formulae:

##STR00090## [0250] in which R and R′ each, independently of one another, denote a straight-chain alkyl or alkoxy radical having 1-7 C atoms. [0251] p) LC medium which additionally comprises one or more monocyclic compounds of the following formula

##STR00091## [0252] wherein [0253] 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, [0254] 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. [0255] 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, [0256] The compounds of the formula Y are preferably selected from the group consisting of the following sub-formulae:

##STR00092## [0257] 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—. [0258] Particularly preferred compounds of the formula Y are selected from the group consisting of the following sub-formulae:

##STR00093## [0259] wherein Alkoxy preferably denotes straight-chain alkoxy with 3, 4, or 5 C atoms. [0260] q) LC medium which, apart from the stabilisers 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). [0261] r) LC medium which comprises 1 to 5, preferably 1, 2 or 3, stabilisers, preferably selected from stabilisers according to the invention, in particular of the formula I or sub-formulae thereof. [0262] s) LC medium in which the proportion of stabilisers, in particular of the formula I or sub-formulae thereof, in the mixture as a whole is 1 to 1500 ppm, preferably 100 to 1000 ppm. [0263] t) 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%. [0264] u) 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%. [0265] v) 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%. [0266] w) 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%. [0267] x) 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%. [0268] y) 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%. [0269] z) 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%.

[0270] In another preferred embodiment of the present invention the LC medium contains an LC host mixture with positive dielectric anisotropy. Preferred embodiments of such an LC medium, and the corresponding LC host mixture, are those of sections aa)-mmm) below: [0271] aa) LC-medium, characterised in that it comprises one or more compounds selected from the group of compounds of the formulae II and III

##STR00094## [0272] wherein [0273] R.sup.20 each, identically or differently, denote a halogenated or unsubstituted alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by —C≡C—, —CF.sub.2O—, —CH═CH—,

##STR00095##  —O—, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another, [0274] X.sup.20 each, identically or differently, denote F, Cl, CN, SF.sub.5, SCN, NCS, a halogenated alkyl radical, a halogenated alkenyl radical, a halogenated alkoxy radical or a halogenated alkenyloxy radical, each having up to 6 C atoms, and [0275] Y.sup.20-24 each, identically or differently, denote H or F; [0276] W denotes H or methyl,

##STR00096##

each, independently of one another, denote

##STR00097## [0277] The compounds of the formula II are preferably selected from the following formulae:

##STR00098## [0278] wherein R.sup.20 and X.sup.20 have the meanings indicated above. [0279] R.sup.20 preferably denotes alkyl having 1 to 6 C atoms. X.sup.20 preferably denotes F. Particular preference is given to compounds of the formulae IIa and IIb, in particular compounds of the formulae IIa and IIb wherein X denotes F. [0280] The compounds of the formula III are preferably selected from the following formulae:

##STR00099## [0281] wherein R.sup.20 and X.sup.20 have the meanings indicated above. [0282] R.sup.20 preferably denotes alkyl having 1 to 6 C atoms. X.sup.20 preferably denotes F. Particular preference is given to compounds of the formulae IIIa and IIIe, in particular compounds of the formula IIIa; [0283] bb) LC-medium additionally comprising one or more compounds selected from the following formulae:

##STR00100## [0284] wherein [0285] R.sup.20, X.sup.20, W and Y.sup.20-23 have the meanings indicated above under formula II, and [0286] Z.sup.20 denotes —C.sub.2H.sub.4—, —(CH.sub.2).sub.4—, —CH═CH—, —CF═CF, —C.sub.2F.sub.4—, —CH.sub.2CF.sub.2—, —CF.sub.2CH.sub.2—, —CH.sub.2O—, —OCH.sub.2—, —COO— or —OCF.sub.2—, in formulae V and VI also a single bond, in formulae V and VIII also —CF.sub.2O—, [0287] r denotes 0 or 1, and [0288] s denotes 0 or 1; [0289] The compounds of the formula IV are preferably selected from the following formulae:

##STR00101## [0290] wherein R.sup.20 and X.sup.20 have the meanings indicated above. [0291] R.sup.20 preferably denotes alkyl having 1 to 6 C atoms. X.sup.20 preferably denotes F or OCF.sub.3, furthermore OCF═CF.sub.2 or C.sub.1; [0292] The compounds of the formula V are preferably selected from the following formulae:

##STR00102## [0293] wherein R.sup.20 and X.sup.20 have the meanings indicated above. [0294] R.sup.20 preferably denotes alkyl having 1 to 6 C atoms. X.sup.20 preferably denotes F and OCF.sub.3, furthermore OCHF.sub.2, CF.sub.3, OCF═CF.sub.2 and OCH═CF.sub.2; [0295] The compounds of the formula VI are preferably selected from the following formulae:

##STR00103## [0296] wherein R.sup.20 and X.sup.20 have the meanings indicated above. [0297] R.sup.20 preferably denotes alkyl having 1 to 6 C atoms. X.sup.20 preferably denotes F, furthermore OCF.sub.3, CF.sub.3, CF═CF.sub.2, OCHF.sub.2 and OCH═CF.sub.2; [0298] The compounds of the formula VII are preferably selected from the following formulae:

##STR00104## [0299] wherein R.sup.20 and X.sup.20 have the meanings indicated above. [0300] R.sup.20 preferably denotes alkyl having 1 to 6 C atoms. X.sup.20 preferably denotes F, furthermore OCF.sub.3, OCHF.sub.2 and OCH═CF.sub.2. [0301] cc) The medium additionally comprises one or more compounds selected from the formulae ZK1 to ZK10 given above. Especially preferred are compounds of formula ZK1 and ZK3. Particularly preferred compounds of formula ZK are selected from the subformulae ZK1a, ZK1b, ZK1c, ZK3a, ZK3b, ZK3c and ZK3d. [0302] dd) The medium additionally comprises one or more compounds selected from the formulae DK1 to DK12 given above. Especially preferred compounds are DK3. [0303] ee) The medium additionally comprises one or more compounds selected from the following formulae:

##STR00105## [0304] wherein X.sup.20 has the meanings indicated above, and [0305] L denotes H or F, [0306] “alkenyl” denotes C.sub.2-6-alkenyl. [0307] ff) The compounds of the formulae DK-3a and IX are preferably selected from the following formulae:

##STR00106## [0308] wherein “alkyl” denotes C.sub.1-6-alkyl, preferably n-C.sub.3H.sub.7, n-C.sub.4H or n-C.sub.5H.sub.11, in particular n-C.sub.3H.sub.7. [0309] gg) The medium additionally comprises one or more compounds selected from the formulae B1, B2 and B3 given above, preferably from the formula B2. The compounds of the formulae B1 to B3 are particularly preferably selected from the formulae B1a, B2a, B2b and B2c. [0310] hh) The medium additionally comprises one or more compounds selected from the following formula:

##STR00107## [0311] wherein L.sup.20 denotes H or F, and R.sup.21 and R.sup.22 each, identically or differently, denote n-alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl, each having up to 6 C atoms, and preferably each, identically or differently, denote alkyl having 1 to 6 C atoms. [0312] ii) The medium comprises one or more compounds of the following formulae:

##STR00108## [0313] Wherein W, R.sup.20, X.sup.20 and Y.sup.20-23 have the meanings indicated in formula III, and

##STR00109##

each, independently of one another, denote

##STR00110##

and

##STR00111##

denotes

##STR00112## [0314] The compounds of the formulae XI and XII are preferably selected from the following formulae:

##STR00113## ##STR00114## [0315] wherein R.sup.20 and X.sup.20 have the meaning indicated above and preferably R.sup.20 denotes alkyl having 1 to 6 C atoms and X.sup.20 denotes F. [0316] The mixture according to the invention particularly preferably comprises at least one compound of the formula XIIa and/or XIIe. [0317] jj) The medium comprises one or more compounds of formula T given above, preferably selected from the group of compounds of the formulae T21 to T23 and T25 to T27. [0318] Particular preference is given to the compounds of the formulae T21 to T23. Very particular preference is given to the compounds of the formulae

##STR00115## [0319] kk) The medium comprises one or more compounds selected from the group of formulae DK9, DK10 and DK11 given above. [0320] ll) The medium additionally comprises one or more compounds selected from the following formulae:

##STR00116## [0321] wherein R.sup.20 and X.sup.20 each, independently of one another, have one of the meanings indicated above, and Y.sup.20-23 each, independently of one another, denote H or F. X.sup.20 is preferably F, Cl, CF.sub.3, OCF.sub.3 or OCHF.sub.2. R.sup.20 preferably denotes alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl, each having up to 6 C atoms. [0322] The mixture according to the invention particularly preferably comprises one or more compounds of the formula XVIII-a,

##STR00117## [0323] wherein R.sup.20 has the meanings indicated above. R.sup.20 preferably denotes straight-chain alkyl, in particular ethyl, n-propyl, n-butyl and n-pentyl and very particularly preferably n-propyl. The compound(s) of the formula XVIII, in particular of the formula XVIII-a, is (are) preferably employed in the mixtures according to the invention in amounts of 0.5-20% by weight, particularly preferably 1-15% by weight. [0324] mm) The medium additionally comprises one or more compounds of the formula XIX,

##STR00118## [0325] wherein R.sup.20, X.sup.20 and Y.sup.20-25 have the meanings indicated in formula I, s denotes 0 or 1, and

##STR00119##

denotes

##STR00120## [0326] In the formula XIX, X.sup.20 may also denote an alkyl radical having 1-6 C atoms or an alkoxy radical having 1-6 C atoms. The alkyl or alkoxy radical is preferably straight-chain. [0327] R.sup.20 preferably denotes alkyl having 1 to 6 C atoms. X.sup.20 preferably denotes F; [0328] The compounds of the formula XIX are preferably selected from the following formulae:

##STR00121## [0329] wherein R.sup.20, X.sup.20 and Y.sup.20 have the meanings indicated above. R.sup.20 preferably denotes alkyl having 1 to 6 C atoms. X.sup.20 preferably denotes F, and Y.sup.20 is preferably F;

##STR00122##

is preferably

##STR00123## [0330] R.sup.20 is straight-chain alkyl or alkenyl having 2 to 6 C atoms; [0331] nn) The medium comprises one or more compounds of the formulae G1 to G4 given above, preferably selected from G1 and G2 wherein alkyl denotes C.sub.1-6-alkyl, L.sup.x denotes H and X denotes F or Cl. In G2, X particularly preferably denotes Cl. [0332] oo) The medium comprises one or more compounds of the following formulae:

##STR00124## [0333] wherein R.sup.20 and X.sup.20 have the meanings indicated above. R.sup.20 preferably denotes alkyl having 1 to 6 C atoms. X.sup.20 preferably denotes F. The medium according to the invention particularly preferably comprises one or more compounds of the formula XXII wherein X.sup.20 preferably denotes F. The compound(s) of the formulae XX-XXII is (are) preferably employed in the mixtures according to the invention in amounts of 1-20% by weight, particularly preferably 1-15% by weight. Particularly preferred mixtures comprise at least one compound of the formula XXII. [0334] pp) The medium comprises one or more compounds of the following pyrimidine or pyridine compounds of the formulae

##STR00125## [0335] wherein R.sup.20 and X.sup.20 have the meanings indicated above. R.sup.20 preferably denotes alkyl having 1 to 6 C atoms. X.sup.20 preferably denotes F. The medium according to the invention particularly preferably comprises one or more compounds of the formula M-1, wherein X.sup.20 preferably denotes F. The compound(s) of the formulae M-1-M-3 is (are) preferably employed in the mixtures according to the invention in amounts of 1-20% by weight, particularly preferably 1-15% by weight.

[0336] Further preferred embodiments are indicated below: [0337] qq) The medium comprises two or more compounds of the formula XII, in particular of the formula XIIe; [0338] rr) The medium comprises 2-30% by weight, preferably 3-20% by weight, particularly preferably 3-15% by weight, of compounds of the formula XII; [0339] ss) Besides the compounds of the formulae XII, the medium comprises further compounds selected from the group of the compounds of the formulae II, III, IX-XIII, XVII and XVIII; [0340] tt) The proportion of compounds of the formulae II, III, IX-XI, XIII, XVII and XVIII in the mixture as a whole is 40 to 95% by weight; [0341] uu) The medium comprises 10-50% by weight, particularly preferably 12-40% by weight, of compounds of the formulae and/or Ill; [0342] vv) The medium comprises 20-70% by weight, particularly preferably 25-65% by weight, of compounds of the formulae IX-XIII; [0343] ww) The medium comprises 4-30% by weight, particularly preferably 5-20% by weight, of compounds of the formula XVII; [0344] xx) The medium comprises 1-20% by weight, particularly preferably 2-15% by weight, of compounds of the formula XVIII; [0345] yy) The medium comprises at least two compounds of the formulae

##STR00126## [0346] zz) The medium comprises at least two compounds of the formulae

##STR00127## [0347] aaa) The medium comprises at least two compounds of the formula XIIa and at least two compounds of the formula XIIe. [0348] bbb) The medium comprises at least one compound of the formula XIIa and at least one compound of the formula Xle and at least one compound of the formula IIIa. [0349] ccc) The medium comprises at least two compounds of the formula XIIa and at least two compounds of the formula Xle and at least one compound of the formula IIIa. [0350] ddd) The medium comprises in total 25% by weight, preferably 30% by weight, of one or more compounds of the formula XII. [0351] eee) The medium comprises 20% by weight, preferably 24% by weight, preferably 25-60% by weight, of compounds of the formula ZK3, in particular the compound of the formula ZK3a,

##STR00128## [0352] fff) The medium comprises at least one compound selected from the group of compounds ZK3a, ZK3b and ZK3c, preferably ZK3a, in combination with compound ZK3d

##STR00129## [0353] ggg) The medium comprises at least one compound of the formula DPGU-n-F. [0354] hhh) The medium comprises at least one compound of the formula CDUQU-n-F. [0355] iii) The medium comprises at least one compound of the formula CPU-n-OXF. [0356] jjj) The medium comprises at least one compound of the formula CPGU-3-OT. [0357] kkk) The medium comprises at least one compound of the formula PPGU-n-F. [0358] lll) The medium comprises at least one compound of the formula PGP-n-m, preferably two or three compounds. [0359] mmm) The medium comprises at least one compound of the formula PGP-2-2V having the structure

##STR00130##

[0360] In a preferred embodiment, the liquid crystal mixture according to the present invention further comprises a polymerizable component C) comprising one or more polymerizable compounds.

[0361] The polymerizable compounds can be selected from isotropic or mesogenic polymerizable compounds known to the skilled person in the art.

[0362] Preferably, the polymerizable component C) comprises one or more polymerizable compounds of formula P,

P.sup.a-(Sp.sup.a).sub.s1-A.sup.2-(Z.sup.a-A.sup.1).sub.n2-(Sp.sup.b).sub.s2—P.sup.b  P

wherein the individual radicals have the following meanings: [0363] P.sup.a, P.sup.b each, independently of one another, denote a polymerizable group, [0364] Sp.sup.a, Sp.sup.b on each occurrence, identically or differently, denote a spacer group, [0365] s1, s2 each, independently of one another, denote 0 or 1, [0366] A.sup.1, A.sup.2 each, independently of one another, denote a radical selected from the following groups: [0367] a) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene and 4,4′-bicyclohexylene, wherein, in addition, one or more non-adjacent CH.sub.2 groups may be replaced by —O— and/or —S— and wherein, in addition, one or more H atoms may be replaced by F, [0368] b) the group consisting of 1,4-phenylene and 1,3-phenylene, wherein, in addition, one or two CH groups may be replaced by N and wherein, in addition, one or more H atoms may be replaced by L, [0369] c) the group consisting of tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, piperidine-1,4-diyl, thiophene-2,5-diyl and selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L, [0370] d) the group consisting of saturated, partially unsaturated or fully unsaturated, and optionally substituted, polycyclic radicals having 5 to 20 cyclic C atoms, one or more of which may, in addition, be replaced by heteroatoms, preferably selected from the group consisting of

##STR00131## [0371] where, in addition, one or more H atoms in these radicals may be replaced by L, and/or one or more double bonds may be replaced by single bonds, and/or one or more CH groups may be replaced by N, [0372] n2 denotes 0, 1, 2 or 3, [0373] Z.sup.a in each case, independently of one another, denotes —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, —O—, —CO—, —C(R.sup.yR.sup.z)—, —CH.sub.2CF.sub.2—, —CF.sub.2CF.sub.2— or a single bond, [0374] L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF.sub.5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms, [0375] R.sup.y, R.sup.z each, independently of one another, denote H, F or straight-chain or branched alkyl having 1 to 12 C atoms, wherein, in addition, one or more H atoms may be replaced by F, [0376] M denotes —O—, —S—, —CH.sub.2—, —CHY.sup.1— or —CY.sup.1Y.sup.2—, and [0377] Y.sup.1 and Y.sup.2 each, independently of one another, have one of the meanings indicated above for R.sup.y or denote C or CN.

[0378] Preferred spacer groups Sp.sup.a,b are selected from the formula Sp″-X″, so that the radicals P-Sp- and P.sup.a/b-Sp.sup.a/b- conforms to the formulae P-Sp″-X″— and P.sup.a/b-Sp″-X″—, respectively, wherein [0379] Sp″ denotes alkylene having 1 to 20, preferably 1 to 12, C atoms, which is optionally mono- or polysubstituted by F, C.sub.0, Br, I or CN and wherein, 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.00R.sup.000)—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —S—CO—, —CO—S—, —N(R.sup.00)—CO—O—, —O—CO—N(R.sup.00)—, —N(R.sup.00)—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, [0380] X″ denotes —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —CO—N(R.sup.00)—, —N(R.sup.00)—CO—, —N(R.sup.00)—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.3═CY.sup.4—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH— or a single bond, [0381] R.sup.0, R.sup.00 and R.sup.000 each, independently of one another, denote H or alkyl having 1 to 12 C atoms, and [0382] Y.sup.3 and Y.sup.4 each, identically or differently, denote H, F, Cl or CN.

[0383] X″ is preferably —O—, —S—, —CO—, —C(O)O—, —OC(O)—, —O—C(O)O—, —CONR.sup.0—, —NR.sup.0—CO—, —NR.sup.0—CO—NR.sup.0— or a single bond.

[0384] Typical spacer groups Sp.sup.11 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—SCH.sub.2CH.sub.2—, —CH.sub.2CH.sub.2—NH—CH.sub.2CH.sub.2— or —(SiR.sup.00R.sup.000—O).sub.p1—, wherein p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R.sup.00 and R.sup.000 have the meanings indicated above.

[0385] Particularly preferred groups -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—O—CO—O—, wherein p1 and q1 have the meanings indicated above.

[0386] Particularly preferred groups Sp″ are, for example, in each case straight-chain ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethyleneN-methyliminoethylene, 1-methylalkylene, ethenylene, propenylene and butenylene.

[0387] Particularly preferred monomers of formula P are the following:

##STR00132## ##STR00133## ##STR00134## ##STR00135##

wherein the individual radicals have the following meanings: [0388] P.sup.1 to P.sup.3 each, independently of one another, denote a polymerizable group as defined for formula P, preferably an acrylate, methacrylate, fluoroacrylate, oxetane, vinyloxy or epoxide group, [0389] Sp.sup.1 to Sp.sup.3 each, independently of one another, denote a single bond or a spacer group, preferably having one of the meanings indicated above and below for Sp.sup.a, and particularly preferably —(CH.sub.2).sub.p1—, —(CH.sub.2).sub.p1—O—, —(CH.sub.2).sub.p1—CO—O— or —(CH.sub.2).sub.p1—O—CO—O—, wherein p1 is an integer from 1 to 12, and where the linking to the adjacent ring in the last-mentioned groups takes place via the O atom, [0390] where, in addition, one or more of the radicals P.sup.1-Sp.sup.1-, P.sup.2—Sp.sup.2- and P.sup.3—Sp.sup.3- may denote a radical 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 does not denote R.sup.aa, [0391] R.sup.aa denotes H, F, Cl, CN or straight-chain or branched alkyl having 1 to 25 C atoms, wherein, 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—, —OCO—, —O—CO—O— in such a way that O and/or S atoms are not linked directly to one another, and wherein, in addition, one or more H atoms may be replaced by F, Cl, CN or P.sup.1—Sp.sup.1-, particularly preferably straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl or alkylcarbonyloxy 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), [0392] R.sup.0, R.sup.00 each, independently of one another, denote H or alkyl having 1 to 12 C atoms, [0393] R.sup.y and R.sup.z each, independently of one another, denote H, F, CH.sub.3 or CF.sub.3, [0394] Z.sup.p1 denotes —O—, —CO—, —C(R.sup.YR.sup.z)— or —CF.sub.2CF.sub.2—, [0395] Z.sup.p2 and Z.sup.p3 each, independently of one another, denote —COO—, —O—CO—, —CH.sub.2O—, —OCH.sub.2—, —CF.sub.2O—, —OCF.sub.2— or —(CH.sub.2).sub.n3—, where n3 is 2, 3 or 4, [0396] L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF.sub.5 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, [0397] L′ and L″ each, independently of one another, denote H, F or C, [0398] r denotes 0, 1, 2, 3 or 4, [0399] s denotes 0, 1, 2 or 3, [0400] t denotes 0, 1 or 2, and [0401] x denotes 0 or 1.

[0402] In a particularly preferred embodiment of the present invention the LC mixture, or component C), comprises one or more compounds of formula P10-1.

##STR00136##

wherein the parameters are defined as described above and P.sup.1 and P.sup.2 preferably denote acrylate or methacrylate.

[0403] Particularly preferred compounds of formula P10-1 are selected from the group of the following subformulae

##STR00137##

wherein each n4 denote independently of each other an integer between 2 and 10, preferably 3, 4, 5 or 6.

[0404] In another preferred embodiment, the polymerizable component C) comprises one or more polymerizable compounds of formula CC,

P.sup.a-Sp.sup.a-(A.sup.p).sub.n2-Sp.sup.b-P.sup.b  CC

wherein the individual radicals have the following meanings: [0405] P.sup.a, P.sup.b each, independently of one another, denote a polymerizable group, preferably each and independently selected from the group consisting of acrylate, methacrylate, ethacrylate, fluoroacrylate, vinyl¬oxy, chloro¬acry-late, oxetane, or epoxide groups [0406] Sp.sup.a, Sp.sup.b on each occurrence, identically or differently, denote a spacer group or a single bond, [0407] A.sup.p each and independently from another, in each occurrence, a group selected from 5, 6 or 7-membered alicyclic groups wherein, in addition, one or more non-adjacent CH.sub.2 groups may be replaced by —NH—, —O— and/or —S—, wherein one or more non-adjacent —CH.sub.2—CH.sub.2— groups may be replaced by —CH═CH—, and wherein one or more H atoms may be replaced by F, [0408] preferably 5-membered groups such as cyclopentane, cyclopentane, tetrahydrofuran, tetrahydrothiofuran, pyrrolidine, or 6-membered groups, such as cyclohexane, silinane, cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1,3-dioxane, 1,3-dithiane, piperidine, or 7-membered groups, such as cycloheptane, trans-1,4-cyclohexylene, [0409] more preferably 1,4-cyclohexylene or 1,4-cyclohexenylene, [0410] n2 denotes 0, 1, 2 or 3, preferably 1 or 2.

[0411] Preferred spacer groups Sp.sup.a,b are selected from the formula Sp″-X″, so that the radicals P-Sp- and P.sup.a/b-Sp.sup.a/b- conforms to the formulae P-Sp″-X″— and P.sup.a/b-Sp″-X″—, respectively, wherein [0412] 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 wherein, 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.00R.sup.000)—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —S—CO—, —CO—S—, —N(R.sup.00)—CO—O—, —O—CO—N(R.sup.00)—, —N(R.sup.00)—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, or a single bond, [0413] X″ denotes —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —CO—N(R.sup.00)—, —N(R.sup.00)—CO—, —N(R.sup.00)—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.3═CY.sup.4—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH— or a single bond, preferably a single bond [0414] R.sup.0, R.sup.00 and R.sup.000 each, independently of one another, denote H or alkyl having 1 to 12 C atoms, and [0415] Y.sup.3 and Y.sup.4 each, identically or differently, denote H, F, Cl or CN.

[0416] X″ is preferably —O—, —S—, —CO—, —C(O)O—, —OC(O)—, —O—C(O)O—, —CO—NR.sup.0—, —NR.sup.0—CO—, —NR.sup.0—CO—NR.sup.0— or a single bond.

[0417] Typical spacer groups Sp.sup.11 are, for example, a single bon, —(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.00R.sup.000—O).sub.p1—, wherein p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R.sup.00 and R.sup.000 have the meanings indicated above.

[0418] Particularly preferred groups -Sp″-X″— are a single bond, —(CH.sub.2).sub.p1—, —(CH.sub.2).sub.p1—O—, —(CH.sub.2).sub.p1—O—CO—, —(CH.sub.2).sub.p1—O—CO—O—, wherein p1 and q1 have the meanings indicated above.

[0419] Particularly preferred groups Sp″ are, for example, in each case straight-chain methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene, ethenylene, propenylene and butenylene.

[0420] Particularly preferred monomers of formula CC are the following:

##STR00138##

[0421] In another preferred embodiment, the polymerizable component C) in accordance with the present invention may comprise, preferably consists of, one or more compounds of formula Palk,

P″-Sp′-P″  Palk

wherein the individual radicals have the meanings: [0422] P″, P″ each, independently of one another, denote a polymerizable group as given in formula 00, [0423] Sp′ denotes a spacer group,

[0424] Preferred spacer groups Sp′ are selected from the formula —X″-Sp″-X″— [0425] Sp″ denotes alkylene having 1 to 25, preferably 1 to 20, C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I, or CN and wherein, 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.00R.sup.000)—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —S—CO—, —CO—S—, —N(R.sup.0)—CO—O—, —O—CO—N(R.sup.00)—, —N(R.sup.00)—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, [0426] X″ denotes each and independently —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —CO—N(R.sup.00)—, —N(R.sup.00)—CO—, —N(R.sup.00)—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.3═CY.sup.4—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH— or a single bond, [0427] R.sup.0, R.sup.00 and R.sup.000 each, independently of one another, denote H or alkyl having 1 to 12 C atoms, and [0428] Y.sup.3 and Y.sup.4 each, identically or differently, denote H, F, Cl or CN.

[0429] X″ is preferably —O—, —S—, —CO—, —C(O)O—, —OC(O)—, —O—C(O)O—, —CONR.sup.0—, —NR.sup.0—CO—, —NR.sup.0—CO—NR.sup.0— or a single bond.

[0430] Typical spacer groups Sp.sup.11 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—SCH.sub.2CH.sub.2—, —CH.sub.2CH.sub.2—NH—CH.sub.2CH.sub.2— or —(SiR.sup.00R.sup.000—O).sub.p1—, wherein p1 and q1 are integers from 1 to 20, and R.sup.00 and R.sup.000 have the meanings indicated above.

[0431] Particularly preferred groups X″-Sp″-X″— are —(CH.sub.2).sub.p1—, —(CH.sub.2CH.sub.2O).sub.q1—CH.sub.2CH.sub.2— —(CH.sub.2).sub.p1—O—, —(CH.sub.2).sub.p1—O—CO—, —(CH.sub.2).sub.p1—O—CO—O—, —O—(CH.sub.2).sub.p1—O—, —O—CO—(CH.sub.2).sub.p1—O—CO—, —O—CO—O—(CH.sub.2).sub.p1—O—CO—O—, —O—(CH.sub.2).sub.p1—, —O—CO—(CH.sub.2).sub.p1—, —O—CO—O—(CH.sub.2).sub.p1—, wherein p1 and q1 have the meanings indicated above.

[0432] Particularly preferred groups Sp″ are, for example, in each case straight-chain ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethyleneN-methyliminoethylene, 1-methylalkylene, ethenylene, propenylene and butenylene,

furthermore —(CH.sub.2CH.sub.2O).sub.q1—(CH.sub.2CH.sub.2).sub.p1—, —(CH.sub.2CH.sub.2).sub.p1—(OCH.sub.2CH.sub.2).sub.q1—, or —(CH.sub.2CH.sub.2).sub.p1—(CH.sub.2CH.sub.2O).sub.q1—(CH.sub.2CH.sub.2)r.sub.1 wherein p1, q1 and r1 each and independently denotes 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12.

[0433] Particularly preferred monomers of formula P are the following:

##STR00139##

[0434] The polymerizable compounds of formulae I, P, CC and Palk are also suitable for polymerisation without an initiator, which is associated with considerable advantages, such as, for example, lower material costs and, in particular, reduced 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 addition of an initiator. The LC medium thus, in a preferred embodiment, comprises no polymerisation initiator.

[0435] The polymerizable component C) or the LC medium as a whole 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. Particularly suitable are, for example, the commercially available stabilisers from the Irganox® series (BASF SE), such as, for example, Irganox® 1076. If stabilisers are employed, their proportion, based on the total amount of the RMs or the polymerizable component, is preferably 10-10,000 ppm, particularly preferably 50-1000 ppm.

[0436] The media according to the invention preferably comprise from 0.01 to 10%, particularly preferably from 0.05 to 7.5% and most preferably from 0.1 to 5% of the compounds of component C) comprising compounds of formula P according to the invention. The media preferably comprise one, two or three, more preferably one or two and most preferably one compound of the formula P according to the invention.

[0437] By means of suitable additives, the liquid-crystalline phases of the present invention can be modified in such a way that they can be used in all types of liquid-crystal display element that have been disclosed hitherto. Additives of this type are known to the person skilled in the art and are described in detail in the literature (H. Kelker/R. Hatz, Handbook of Liquid Crystals, Verlag Chemie, Weinheim, 1980). For example, pleochroic dyes can be added for the production of coloured guest-host systems or substances can be added in order to modify the dielectric anisotropy, the viscosity and/or the alignment of the nematic phases.

[0438] The media according to the invention are prepared in a manner conventional per se. In general, the components are dissolved in one another, preferably at elevated temperature.

[0439] Accordingly the present invention relates further to method for the production of an LC medium according to the present invention, comprising the step of mixing one or more compounds of formula I with a liquid-crystalline component B) comprising one or more mesogenic or liquid-crystalline compounds as described above.

[0440] The present invention further relates to a process for the fabrication of liquid crystal displays comprising at least the steps of: [0441] providing a first substrate which includes a pixel electrode and a common electrode for generating an electric field substantially parallel to a surface of the first substrate in the pixel region; [0442] providing a second substrate, the second substrate being disposed opposite to the first substrate; [0443] interposing a liquid crystal mixture between the first substrate and the second substrate, the liquid crystal mixture comprising one or more compounds of formula I, component B) and optionally component C); [0444] irradiating the liquid crystal mixture with linearly polarised light causing photoalignment of the liquid crystal; [0445] curing the polymerizable compounds of the liquid crystal mixture by irradiation with ultraviolet light or visible light having a wavelength of 450 nm or below.

[0446] The present invention further relates to the use of the liquid crystal mixtures according to the invention for the fabrication of a liquid crystal display.

[0447] The present invention further relates to liquid crystal displays fabricated by the process described above.

[0448] In the following, the production process according to the present invention is described in greater detail.

[0449] The first substrate includes a pixel electrode and a common electrode for generating an electric field substantially parallel to a surface of the first substrate in the pixel region. Various kinds of displays having at least two electrodes on one substrate are known to the skilled person wherein the most significant difference is that either both the pixel electrode and the common electrode are structured, as it is typical for IPS displays, or only the pixel electrode is structured and the common electrode is unstructured, which is the case for FFS displays.

[0450] It has to be understood that the present invention refers to any kind of electrode configurations suitable for generating an electric field substantially parallel to a surface of the first substrate in the pixel region; mentioned above, i.e. IPS as well as FFS displays.

[0451] The process according to the present invention is independent of the kind of substrate or material of the surface which is in contact with the liquid crystal mixture according to the invention, during and after this process. Examples of materials used for the substrates or surfaces are organic polymers including polyimide, indium tin oxide (ITO), indium zinc oxide (IZO), silicon nitride (SiN.sub.x) and silicon dioxide (SiO.sub.2). The process is especially suitable for the use in displays containing substrates that do not have a polyimide layer on one or more of the surfaces that are in contact with the liquid crystal.

[0452] In case one or more substrates contain a polyimide layer, the polyimide can be rubbed or not rubbed, preferably not rubbed.

[0453] Hence, the invention relates to a display produced by the process according to the invention in which the substrates contain a rubbed or unrubbed polyimide layer, preferably an unrubbed polyimide layer.

[0454] The invention further relates to a display produced by the process according to the invention in which none or only one of the top and bottom substrates contains a polyimide layer.

[0455] In one embodiment of the present invention the liquid crystal composition is injected between the first and second substrates or is filled into the cell by capillary force after combining the first and second substrates. In an alternative embodiment, the liquid crystal composition may be interposed between the first and second substrates by combining the second substrate to the first substrate after loading the liquid crystal composition on the first substrate. Preferably, the liquid crystal is dispensed dropwise onto a first substrate in a process known as “one drop filling” (ODF) process, as disclosed in for example JPS63-179323 and JPH10-239694, or using the Ink Jet Printing (IJP) method.

[0456] In a preferred embodiment, the process according to the invention contains a process step where the liquid crystal inside the display panel is allowed to rest for a period of time in order to evenly redistribute the liquid crystal medium inside the panel (herein referred to as “annealing”).

[0457] However it is likewise preferred that the annealing step is combined with a previous step, such as edge sealant pre-curing. In which case a ‘separate’ annealing step may not be necessary at all.

[0458] For the production of the displays according to the present invention, the photoreactive mesogen of formula I is preferably allowed to redistribute in the panel. After filling and assembly, the display panel is annealed for a time between 1 min and 3 h, preferably between 2 min and 1 h and most preferably between 5 min and 30 min. The annealing is preferably performed at room temperature.

[0459] In an alternative embodiment, the annealing is performed at elevated temperature, preferably at above 20° C. and below 140° C., more preferably above 40° C. and below 100° C. and most preferably above 50° C. and below 80° C.

[0460] In a preferred embodiment, one or more of the process steps of filling the display, annealing, photoalignment and curing of the polymerizable compound is performed at a temperature above the clearing point of the liquid crystal host mixture.

[0461] During the photoalignment of the liquid crystal inside the liquid crystal panel, anisotropy is induced by exposing the display or the liquid crystal layer to linearly polarised light.

[0462] In a preferred embodiment of the present invention the photoreactive component A) comprising one or more compounds of formula I, is photoaligned in a first step using linearly polarised light and in a second step further cured using linearly polarized or unpolarised UV light. In the second step the optional component C) is also further cured.

[0463] In another preferred embodiment, the linearly polarised light applied according to the inventive process is ultraviolet light which enables simultaneous photoalignment and photocuring of the photoreactive component A) comprising one or more compounds of formula I, and, if present, photocuring of the polymerizable component C).

[0464] Photoalignment of the photoreactive compounds of formula I and curing of the polymerizable groups of compounds of formula I and the curing of the optional polymerizable compounds of formula P can be performed simultaneously or stepwise. In case the process is split into different steps, the individual steps can be performed at the same temperature or at different temperatures.

[0465] After the photoalignment and curing step(s) a so-called “post-curing” step can optionally be performed by irradiation with UV-light and/or visible light (both either linearly or unpolarised) at reduced temperature in order to remove unreacted polymerizable compounds. The post-curing is preferably performed at above 0° C. and below the clearing point of the utilized LC mixture, preferably 20° C. and below 60° C.° C., and most preferably above 20° C. and below 40° C.

[0466] The polymerizable compounds are optionally polymerised or crosslinked (if a polymerizable compound contains two or more polymerizable groups) with the application of an electrical field. The polymerisation can be carried out in one or more steps.

[0467] Suitable and preferred polymerisation methods for component C) are, for example, thermal or photopolymerization, preferably photopolymerization, in particular UV photopolymerization. One or more initiators can optionally also be added here. 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 Darocurel 173® (BASF SE). If an initiator is employed, its proportion is preferably 0.001 to 5% by weight, particularly preferably 0.001 to 1% by weight.

[0468] The present invention also relates to electro-optical liquid-crystal display elements containing a liquid-crystalline medium according to the invention, which is preferably homogeneously aligned. In a preferred embodiment the liquid crystal display is of the IPS or FFS mode.

[0469] Further combinations of the embodiments and variants of the invention in accordance with the description arise from the claims.

[0470] The invention is explained in greater detail below with reference to working examples, but without intending to be restricted thereby. The person skilled in the art will be able to glean from the examples working details that are not given in detail in the general description, generalise them in accordance with general expert knowledge and apply them to a specific problem.

[0471] Besides the usual and well-known abbreviations, the following abbreviations are used:

[0472] C: crystalline phase; N: nematic phase; Sm: smectic phase; I: isotropic phase. The numbers between these symbols show the transition temperatures of the substance concerned.

[0473] Temperature data are in ° C., unless indicated otherwise.

[0474] Physical, physicochemical or electro-optical parameters are determined by generally known methods, as described, inter alia, in the brochure “Merck Liquid Crystals—Licristal®—Physical Properties of Liquid Crystals—Description of the Measurement Methods”, 1998, Merck KGaA, Darmstadt.

[0475] Above and below, Δn denotes the optical anisotropy (589 nm, 20° C.) and Δε denotes the dielectric anisotropy (1 kHz, 20° C.). The dielectric anisotropy Δε is determined at 20° C. and 1 kHz. The optical anisotropy Δn is determined at 20° C. and a wavelength of 589.3 nm.

[0476] The Δε and Δn values and the rotational viscosity (γ.sub.1) of the compounds according to the invention are obtained by linear extrapolation from liquid-crystalline mixtures consisting of 5 to 10% of the respective compound according to the invention and 90-95% of the commercially available liquid-crystal mixture ZLI-2857 (for Δε) or ZLI-4792 (for Δn, γ.sub.1) (mixtures, Merck KGaA, Darmstadt).

[0477] The compounds used in the present invention are prepared by methods known per se, as described in the literature (for example in the standard works, such as Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart), to be precise under reaction conditions which are known and suitable for the said reactions. Use can also be made here of variants known per se, which are not mentioned here in greater detail.

[0478] In the present invention and especially in the following examples, the structures of the mesogenic compounds are indicated by means of abbreviations, also called acronyms. In these acronyms, the chemical formulae are abbreviated as follows using Tables A to C below. All groups C.sub.nH.sub.2n+1, C.sub.mH.sub.2m+1 and C.sub.lH.sub.2l+1 or C.sub.nH.sub.2n−1, C.sub.mH.sub.2m−1 and C.sub.lH.sub.2l−1 denote straight-chain alkyl or alkenyl, preferably 1E-alkenyl, each having n, m and l C atoms respectively. Table A lists the codes used for the ring elements of the core structures of the compounds, while Table B shows the linking groups. Table C gives the meanings of the codes for the left-hand or right-hand end groups. The acronyms are composed of the codes for the ring elements with optional linking groups, followed by a first hyphen and the codes for the left-hand end group, and a second hyphen and the codes for the right-hand end group. Table D shows illustrative structures of compounds together with their respective abbreviations.

TABLE-US-00001 TABLE A Ring elements C [00140] P [00141] D [00142] DI [00143] A [00144] AI [00145] G [00146] GI [00147] U [00148] UI [00149] Y [00150] M [00151] MI [00152] N [00153] NI [00154] Np [00155] dH [00156] N3f [00157] N3fI [00158] tH [00159] tHI [00160] tH2f [00161] tH2fI [00162] K [00163] KI [00164] L [00165] LI [00166] F [00167] FI [00168] Nf [00169] NfI [00170]

TABLE-US-00002 TABLE B Linking groups E —CH.sub.2CH.sub.2— Z —CO—O— V —CH═CH— ZI —O—CO— X —CF═CH— O —CH.sub.2—O— XI —CH═CF— OI —O—CH.sub.2— B —CF═CF— Q —CF.sub.2—O— T —C≡C— QI —O—CF.sub.2— W —CF.sub.2CF.sub.2— T —C≡C—

TABLE-US-00003 TABLE C End groups Left-hand side Right-hand side Use alone -n- C.sub.nH.sub.2n+1— -n —C.sub.nH.sub.2n+1 -nO- C.sub.nH.sub.2n+1—O— -nO —O—C.sub.nH.sub.2n+1 -V- CH.sub.2═CH— -V —CH═CH.sub.2 -nV- C.sub.nH.sub.2n+1—CH═CH— -nV —C.sub.nH.sub.2n—CH═CH.sub.2 -Vn- CH.sub.2═CH— C.sub.nH.sub.2n+1— -Vn —CH═CH—CnH.sub.2n+1 -nVm- C.sub.nH.sub.2n+1—CH═CH—C.sub.mH.sub.2m— -nVm —C.sub.nH.sub.2n—CH═CH—C.sub.mH.sub.2m+1 -N- N≡C— -N —C≡N -S- S═C═N— -S —N═C═S -F- F— -F —F -CL- Cl— -CL —Cl -M- CFH.sub.2— -M —CFH.sub.2 -D- CF.sub.2H— -D —CF.sub.2H -T- CF.sub.3— -T —CF.sub.3 -MO- CFH.sub.2O — -OM —OCFH.sub.2 -DO- CF.sub.2HO — -OD —OCF.sub.2H -TO- CF.sub.3O— -OT —OCF.sub.3 -FXO- CF.sub.2═CH—O— -OXF —O—CH═CF.sub.2 -A- H—C≡C— -A —C≡C—H -nA- C.sub.nH.sub.2n+1—C≡C— -An —C≡C—C.sub.nH.sub.2n+1 -NA- N≡C—C≡C— -AN —C≡C—C≡N Use together with one another and with others - . . . A . . . - —C≡— - . . . A . . . —C≡— - . . . V . . . - CH═CH— - . . . V . . . —CH═CH— - . . . Z . . . - —CO—O— - . . . Z . . . —CO—O— - . . . ZI . . . - —O—CO— - . . . ZI . . . —O—CO— - . . . K . . . - —CO— - . . . K —CO— - . . . W . . . - —CF═CF— - . . . W . . . —CF═CF—
wherein n and m each denote integers, and the three dots “ . . . ” are placeholders for other abbreviations from this table.

[0479] The following table shows illustrative structures together with their respective abbreviations. These are shown in order to illustrate the meaning of the rules for the abbreviations. They furthermore represent compounds which are preferably used.

TABLE-US-00004 TABLE D Illustrative structures [00171] CC-n-m [00172] CC-n-Om [00173] CC-n-V [00174] CC-n-Vm [00175] CC-n-mV [00176] CC-n-mVI [00177] CC-V-V [00178] CC-V-mV [00179] CC-V-Vm [00180] CC-Vn-mV [00181] CC-nV-mV [00182] CC-nV-Vm [00183] CP-n-m [00184] CP-nO-m [00185] CP-n-Om [00186] CP-V-m [00187] CP-Vn-m [00188] CP-nV-m [00189] CP-V-V [00190] CP-V-mV [00191] CP-V-Vm [00192] CP-Vn-mV [00193] CP-nV-mV [00194] CP-nV-Vm [00195] PP-n-m [00196] PP-nO-m [00197] PP-n-Om [00198] PP-n-V [00199] PP-n-Vm [00200] PP-n-mV [00201] PP-n-mVI [00202] CCP-n-m [00203] CCP-nO-m [00204] CCP-n-Om [00205] CCP-n-V [00206] CCP-n-Vm [00207] CCP-n-mV [00208] CCP-n-mVI [00209] CCP-V-m [00210] CCP-nV-m [00211] CCP-Vn-m [00212] CCP-nVm-I [00213] CPP-n-m [00214] CPG-n-m [00215] CGP-n-m [00216] CPP-nO-m [00217] CPP-n-Om [00218] CPP-V-m [00219] CPP-nV-m [00220] CPP-Vn-m [00221] CPP-nVm-I [00222] PGP-n-m [00223] PGP-n-V [00224] PGP-n-Vm [00225] PGP-n-mV [00226] PGP-n-mVI [00227] CCEC-n-m [00228] CCEC-n-Om [00229] CCEP-n-m [00230] CCEP-n-Om [00231] CPPC-n-m [00232] CGPC-n-m [00233] CCPC-n-m [00234] CCZPC-n-m [00235] CPGP-n-m [00236] CPGP-n-mV [00237] CPGP-n-mVI [00238] PGIGP-n-m [00239] CP-n-F [00240] CP-n-CL [00241] GP-n-F [00242] GP-n-CL [00243] CCP-n-OT [00244] CCG-n-OT [00245] CCP-n-T [00246] CCG-n-F [00247] CCG-V-F [00248] CCG-V-F [00249] CCU-n-F [00250] CDU-n-F [00251] CPG-n-F [00252] CPU-n-F [00253] CGU-n-F [00254] PGU-n-F [00255] GGP-n-F [00256] GGP-n-CL [00257] PGIGI-n-F [00258] PGIGI-n-CL [00259] CCPU-n-F [00260] CCGU-n-F [00261] CPGU-n-F [00262] CPGU-n-OT [00263] DPGU-n-F [00264] PPGU-n-F [00265] CCZU-n-F [00266] CCQP-n-F [00267] CCQG-n-F [00268] CCQU-n-F [00269] PPQG-n-F [00270] PPQU-n-F [00271] PGQU-n-F [00272] GGQU-n-F [00273] PUQU-n-F [00274] MUQU-n-F [00275] NUQU-n-F [00276] CDUQU-n-F [00277] CPUQU-n-F [00278] CGUQU-n-F [00279] PGPQP-n-F [00280] PGPQG-n-F [00281] PGPQU-n-F [00282] PGUQU-n-F [00283] APUQU-n-F [00284] DGUQU-n-F [00285] CY-n-Om [00286] CY-n-m [00287] CY-V-Om [00288] CY-nV-(O)m [00289] CVC-n-m [00290] CVY-V-m [00291] CEY-V-m [00292] PY-n-(O)m [00293] CCY-n-m [00294] CCY-n-Om [00295] CCY-V-m [00296] CCY-Vn-m [00297] CCY-V-Om [00298] CCY-n-OmV [00299] CCY-n-zOm [00300] CCOC-n-m [00301] CPY-n-(O)m [00302] CPY-V-Om [00303] CQY-n-(O)m [00304] CQIY-n-(O)m [00305] CCQY-n-(O)m [00306] CCQIY-n-(O)m [00307] CPQY-n-(O)m [00308] CPQIY-n-Om [00309] CLY-n-(O)m [00310] CYLI-n-m [00311] LYLI-n-m [00312] LY-n-(O)m [00313] PGIGI-n-F [00314] PGP-n-m [00315] PYP-n-(O)m [00316] PYP-n-mV [00317] YPY-n-m [00318] YPY-n-mV [00319] BCH-nm [00320] BCH-nmF [00321] CPYP-n-(O)m [00322] CPGP-n-m [00323] CPYC-n-m [00324] CYYC-n-m [00325] CCYY-n-m [00326] CPYG-n-(O)m [00327] CBC-nm [00328] CBC-nmF [00329] CNap-n-Om [00330] CCNap-n-Om [00331] CENap-n-Om [00332] CTNap-n-Om [00333] CETNap-n-Om [00334] CK-n-F [00335] DFDBC-n(O)-(O)m [00336] C-DFDBF-n-(O)m
wherein n, m and l preferably, independently of one another, denote 1 to 7.

[0480] The following table, Table E, shows illustrative compounds which can be used as additional stabilisers in the mesogenic media according to the present invention.

TABLE-US-00005 TABLE E Table E shows possible stabilisers which can be added to the LC media according to the invention. (n here denotes an integer from 1 to 12, preferably 1, 2, 3, 4, 5, 6, 7 or 8, terminal methyl groups are not shown). [00337] [00338] [00339] [00340] [00341] [00342] [00343] [00344] [00345] [00346] [00347] [00348] [00349] [00350] [00351] [00352] [00353] [00354] [00355] [00356] [00357] [00358] [00359] [00360] [00361] [00362] [00363] [00364] [00365] [00366] [00367] [00368] [00369] [00370] [00371] [00372] [00373] [00374] [00375] [00376] [00377] [00378] [00379] [00380] [00381]

[0481] The LC media preferably comprise 0 to 10% by weight, in particular 1 ppm to 5% by weight, particularly preferably 1 ppm to 1% by weight, of stabilisers.

[0482] Table F below shows illustrative compounds which can preferably be used as chiral dopants in the mesogenic media according to the present invention.

TABLE-US-00006 TABLE F [00382] C15 [00383] CB 15 [00384] CM 21 [00385] CM 44 [00386] CM 45 [00387] CM 47 [00388] CC [00389] CN [00390] R/S-811 [00391] R/S-1011 [00392] R/S-2011 [00393] R/S-3011 [00394] R/S-4011 [00395] R/S-5011

[0483] In a preferred embodiment of the present invention, the mesogenic media comprise one or more compounds selected from the group of the compounds from Table F.

[0484] The mesogenic media according to the present application preferably comprise two or more, preferably four or more, compounds selected from the group consisting of the compounds from the above tables.

[0485] The liquid-crystal media according to the present invention preferably comprise [0486] seven or more, preferably eight or more, individual compounds, preferably of three or more, particularly preferably of four or more, different formulae, selected from the group of the compounds from Table D.

[0487] Hereinafter, the present invention is described in more detail and specifically with reference to the Examples, which however are not intended to limit the present invention.

EXAMPLES

Compound Examples

1.1 Synthesis of diethyl 3-(2-benzyloxyethyl)pentanedioate (1)

[0488] ##STR00396##

[0489] Under reflux 13.8 ml (90 mmol) of the diethyl malonate are added to mixture of 34.5 ml of a solution of sodium methylate in ethanol (20%, 50 mmol) and 40 ml ethanol. After 2 h 10 g (50 mmol) of 2-bromoethoxymethylbenzene are added and heating was continued overnight. Water and MTB ether are poured into the cooled reaction mixture. The aqueous layer is extracted with MTB ether. The combined organic layers are washed with brine and dried over sodium sulfate. The solvent is evaporated. The residue is purified by silica chromatography (toluene; toluene/MTB ether 9:1). The isolated material is distilled under vacuum (0.1 mbar, 116-121° C.).

1.2 Synthesis of 2-(2-benzyloxyethyl)propane-1,3-diol (2)

[0490] ##STR00397##

[0491] A solution of 5 g (20 mmol) of the malonate 1 in 60 ml toluene is added to a suspension of 930 mg (24 mmol) Lithium aluminum hydride in 8 ml Toluene. After 3 h reflux the cooled reaction mixture is quenched with ethyl acetate. The mixture is acidified with 2 mol/1 hydrochloric acid (pH 3-4). The aqueous layer is extracted with MTB ether. The combined organic layers are washed with water and dried over sodium sulfate. The solvent is evaporated. The residue is purified by silica chromatography (ethyl acetate.

1.3 Synthesis of [4-benzyloxy-2-[[tertbutyl(dimethyl)silyl]oxymethyl]butoxy]-tert-butyl-dimethyl-silane (3)

[0492] ##STR00398##

[0493] At roomtemp. 3.4 ml (25 mmol) triethyl amine are added to a mixture of 2.1 g (10 mmol) of the diol 2 and 120 mg DMAP dissolved in 30 ml dichloro methane. Afterwards a solution of 4.5 g (30 mmol) TBDMS-Cl in 15 ml dichloro methane are added to the reaction mixture at 3-4° C. After stirring 16 h at roomtemp. the mixture is quenched with water. The combined organic layers are washed with brine and dried over sodium sulfate. The solvent is evaporated. The residue is purified by silica chromatography (n-heptane/ethyl acetate 19:1).

1.4 Synthesis of 4-[tert-butyl(dimethyl)silyl]oxy-3-[[tertbutyl(dimethyl)silyl]oxy-methyl]-butan-1-ol (4)

[0494] ##STR00399##

[0495] A solution of 500 mg (1 mmol) of 3 in 13 ml ethyl acetate is hydrogenated using Pd/C-5% at roomtemp. The solvent is evaporated. The residue is purified by silica chromatography (n-heptane/ethyl acetate (gradient)).

1.5 Synthesis of (E)-1,3-bis(4-hydroxyphenyl)prop-2-en-1-one (5)

[0496] ##STR00400##

[0497] To solution of 10 g (37 mmol) (E)-1,3-bis(4-methoxyphenyl)prop-2-en-1-one in 95 ml DCM, 149 ml 1 mol/1 Bortribromide in DCM is added and stirred overnight at room temperature. The mixture is poured into a mixture of ice and water while vigorously stirring. The crude mixture is extracted with MTBE and the combined organic phases are dried with sodium sulfate. After filtration and evaporation of the solvent, the crude product is purified over silica gel (eluent DCM/MTBE, 9:1) and recrystallized from acetonitrile

1.6 Synthesis of (E)-1,3-bis[4-[3,3-bis[[tertbutyl(dimethyl)silyl]oxymethyl]pentoxy]phenyl]prop-2-en-1-one (6)

[0498] ##STR00401##

[0499] To a mixture of 3 g (12.5 mmol) (E)-1,3-bis(4-hydroxyphenyl)prop-2-en-1-one (5), 10.3 g (27.3 mmol) -[tert-butyl(dimethyl)silyl]oxy-3-[[tertbutyl(dimethyl)silyl]oxy-methyl]-butan-1-ol (4) and 7.5 g (28.7 mmol) Triphenyl phosphine in 25 ml THF, 5.9 ml (30 mmol) Diisopropylazodicarboxylate are added slowly not exceeding a temperature of 35° C. and stirred over night. Isolute @ HM-N is added to the solvent is evaporated. The crude product is then purified over silica gel (eluent: chlorobutane) to give 2 g of (E)-1,3-bis[4-[3,3-bis[[tertbutyl(dimethyl)silyl]oxymethyl]pentoxy]phenyl]prop-2-en-1-one (6)

1.7 Synthesis of (E)-1,3-bis[4-[3,3-bis(hydroxymethyl)pentoxy]phenyl]prop-2-en-1-one (7)

[0500] ##STR00402##

[0501] To a solution of 2 g (2 mmol) (E)-1,3-bis[4-[3,3-bis[[tertbutyl(dimethyl)silyl]oxymethyl]pentoxy]phenyl]prop-2-en-1-one (6), 3.4 ml (21 mmol) Triethylaminotrishydrofluoride in 13 ml DCM are added at room temperature and stirred overnight. Isolute @ HM-N is added to the crude mixture and the solvent is evaporated the crude product is purified over silica gel (eluent: DCM/THF, gradient 30-60%) to give Ausbeute 840 mg of (E)-1,3-bis[4-[3,3-bis(hydroxymethyl)pentoxy]phenyl]prop-2-en-1-one (7).

1.8 Synthesis of [4-[4-[(E)-3-[4-[3,3-bis(2-methylprop-2-enoyloxymethyl)pentoxy]phenyl]prop-2-enoyl]phenoxy]-2-ethyl-2-[(2-methyl-1-methylene-allyloxy)methyl]butyl] 2-methylprop-2-enoate (8)

[0502] ##STR00403##

[0503] To a suspension consisting of 840 mg (1.7 mmol) (E)-1,3-bis[4-[3,3-bis(hydroxymethyl)pentoxy]phenyl]prop-2-en-1-one and 33 mg DMAP in 5 ml DCM, 0.9 ml Methacrylic acid (10.5 mmol) and 1.9 ml (10.5 mmol) N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimid are added not exceeding a temperature of 5° C. After further stirring for 1 h at that temperature the mixture is stirred over night. The crude mixture is filtrated over silica gel (DCM) and the solvent is evaporated. The crude product is purified by column chromatography (ACN/H2O (15%)) to give 350 mg [4-[4-[(E)-3-[4-[3,3-bis(2-methylprop-2-enoyloxymethyl)pentoxy]phenyl]prop-2-enoyl]phenoxy]-2-ethyl-2-[(2-methyl-1-methylene-allyloxy)methyl]butyl] 2-methylprop-2-enoate (8).

[0504] EI-MS (m/z): 772=M.sup.+; 267; 69; 41

[0505] Phase: Tg −20° C. K 63 l

[0506] .sup.1H NMR (700 MHz, Chloroform-d) δ 8.03-7.98 (m, 2H), 7.76 (d, J=15.6 Hz, 1H), 7.60-7.55 (m, 2H), 7.41 (d, J=15.4 Hz, 1H), 6.95-6.91 (m, 2H), 6.91-6.86 (m, 2H), 6.11-6.08 (m, 4H), 5.57 (m, 4H), 4.19-4.10 (m, 12H), 1.94 (s, 12H), 1.60-1.53 (m, 9H), 0.96 (2t, J=7.5 Hz, 6H).

[0507] Nematic Host Mixtures

[0508] The nematic LC host mixture N-1 is prepared as indicated in the following table:

TABLE-US-00007 Mixture N-1: Composition [%-w/w] Physical properties CC-3-V 36.00 CC-3-V1 5.00 cl.p. [° C.]: 78 CCP-V-1 8.00 n.sub.e [589 nm, 20° C.]: 1.5907 PGP-2-2V 3.00 Δn [589 nm, 20° C.]: 0.1095 CCQU-3-F 9.5 ε.sub.∥ [1 kHz, 20° C.]: 16.6 PUQU-3-F 8.5 ε.sub.⊥ [1 kHz, 20° C.]: 3.7 APUQU-2-F 5.00 Δε [1 kHz, 20° C.]: 12.9 APUQU-3-F 8.00 K.sub.1 [pN, 20° C.]: 12.1 PGUQU-3-F 4.00 K.sub.3 [pN, 20° C.]: 13.4 PGUQU-4-F 8.00 K.sub.3/K.sub.1 [pN, 20° C.]: 1.11 PGUQU-5-F 5.00 V.sub.0 [V, 20° C.]: 1.01 Σ 100.0 LTS bulk [h, −20° C.]: 1000

[0509] Fabrication of Display Cells

[0510] Unless explicitly stated otherwise, the display cells are made with Corning AF glass of 0.7 mm thickness using 6.4 μm spacer beads and XN-1500T sealant.

[0511] For measurement of electro-optics 3 μm thick PI-free IPS cells are made of substrates commercially available from SD-tech and constructed into cells using ITO electrodes having 5 μm electrode spacing and a 3 μm electrode width.

[0512] The cells are assembled by hand and then cured using a Omnicure 2000 Mercury lamp with 35 mW/cm.sup.2 the irradiation power is thereby measured by an Opsytec UV pad-e spectroradiometer.

[0513] Mixture Examples

[0514] The following nematic LC mixtures according to the invention are prepared from the nematic host mixtures listed above and photoalignment additives of formula I, according to the compositions given in the following table.

TABLE-US-00008 c [%] of Mixture Host Host Photoalignment additive example Mixture Mixture Compound c [%] M-1 N-1 99.00 8 1.00

[0515] Cell Filling and Curing

[0516] Unless explicitly stated otherwise, the selected LC mixtures are capillary filled using capillary action at room temp., annealed for 1 h at 100° C. and then irradiated at the same temperature with linearly polarised UV light (35 mW/cm.sup.2) for the given time. The cells are then cooled to room temperature. Next, the alignment quality is studied between crossed polarisers on a light box.

TABLE-US-00009 Host mixture Compound Curing time Example [%] [%] [s] Alignment M-1 N-1 99.00 8 1.00 60 ++ M-1 N-1 99.00 8 1.00 120 ++ Alignment quality: (++) excellent, (+) good, (o) acceptable, (−) poor

[0517] Excellent uniform planar alignment is achieved with all mixture according to the present invention and under all polarizer configurations an homogeneous transmissive state is observed.

[0518] VHR Measurements

[0519] Unless explicitly stated otherwise, the selected LC mixtures are capillary filled using capillary action at room temp., annealed for 1 h at 100° C. (initial) and then irradiated for 1 min. at the same temperature with linearly polarised UV light (35 mW/cm2) from an Omnicure S2000 mercury lamp with a built in 320-500 nm filter utilizing an additional 360 nm long pass filter (cuts off shorter wavelengths from 320-360 nm) (1.sup.st UV).

[0520] The cells are then cooled to room temperature and then irradiated with linearly polarised UV light (35 mW/cm2) from an Omnicure S2000 mercury lamp with a built in 320-500 nm filter utilizing an additional 360 nm long pass filter (cuts off shorter wavelengths from 320-360 nm) for 5 minutes (2.sup.nd UV).

[0521] Next, the VHR is studied using Toyo LCM-1 LC Material Characteristics Measurement System. Unless described otherwise, the measurement of the VHR is carried out as described in T. Jacob, U. Finkenzeller in “Merck Liquid Crystals—Physical Properties of Liquid Crystals”, 1997.

[0522] VHR measured at 60° C., 60 Hz and 1 V initial and after first and second curing with 360 nm cut off filter

TABLE-US-00010 Photoalignment Host mixture compound VHR Example [%] [%] [%] M-1 N-1 99.00 8 1.00 99.5 (initial) .sup.  M-1 N-1 99.00 8 1.00 91.0 (1st UV)  M-1 N-1 99.00 8 1.00 93.9 (2nd UV)

[0523] VHR measured at 60° C., 3 Hz and 1 V initial and after first and second curing with 360 nm cut off filter

TABLE-US-00011 Photoalignment Host mixture compound VHR Example [%] [%] [%] M-1 N-1 99.00 8 1.00 95.5 (initial) .sup.  M-1 N-1 99.00 8 1.00 47.3 (1st UV)  M-1 N-1 99.00 8 1.00 76.5 (2nd UV)

[0524] As can be seen from the above-given tables the VHR of test cells in accordance with the present invention show excellent values.