Birefringent RM lens

Abstract

The invention relates to a birefringent RM lens obtainable from a polymerizable liquid crystalline medium consisting of a polymerizable liquid crystalline component A, consisting of one or more polymerizable mesogenic compounds, and a non-polymerizable component B, consisting of one or more non-polymerizable compounds
and to the use of such birefringent RM lenses in electro optical devices, such as liquid crystal displays (LCDs) or other optical or electrooptical devices, for decorative or security applications.

Claims

1. A birefringent reactive mesogen lens obtainable from a polymerizable liquid crystalline medium consisting of: a polymerizable liquid crystalline component (A) consisting of one or more polymerizable mesogenic compounds, and a non-polymerizable component (B) consisting of one or more non-polymerizable compounds, wherein said liquid crystalline medium exhibits a homogeneous planar alignment throughout the whole lens, and wherein said lens has a plano-convex shape, and wherein the amount of the polymerizable liquid crystalline component (A) in the liquid crystalline medium is more than 95% by weight of the total liquid crystalline medium.

2. A birefringent reactive mesogen lens according to claim 1, wherein polymerizable liquid crystalline component (A) comprises at least one polymerizable mesogenic compound selected from formula I,
P-Sp-MG-R.sup.0I wherein P is a polymerizable group, Sp is a spacer group or a single bond, MG is a rod-shaped mesogenic group of formula M,
-(A.sup.21-Z.sup.21).sub.k-A.sup.22-(Z.sup.22-A.sup.23).sub.l-M A.sup.21 to A.sup.23 are in each occurrence independently of one another an aryl-, heteroaryl-, heterocyclic- or alicyclic group, which in each case is optionally substituted by one or more identical or different groups L, Z.sup.21 and Z.sup.22 are, in each occurrence independently from each other, O, S, CO, COO, OCO, SCO, COS, OCOO, CONR.sup.01, NR.sup.01CO, NR.sup.01CONR.sup.02, NR.sup.01COO, OCONR.sup.01, OCH.sub.2, CH.sub.2O, SCH.sub.2, CH.sub.2S, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, CF.sub.2CF.sub.2, CHN, NCH, NN, CHCR.sup.01, CY.sup.01CY.sup.02, CC, CHCHCOO, OCOCHCH, or a single bond, L is, in case of multiple occurrences independently of one another, H, halogen, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, with up to 5 C atoms, R.sup.0 is H, alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, with up to 20 C atoms or is Y.sup.0 or P-Sp-, Y.sup.0 is F, Cl, CN, NO.sub.2, OCH.sub.3, OCN, SCN, optionally fluorinated alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, with up to 4 C atoms, or mono-, oligo- or polyfluorinated alkyl or alkoxy with 1 to 4 C atoms, Y.sup.01 and Y.sup.02 each, independently of one another, denote H, F, Cl or CN, R.sup.01 and R.sup.02 are independently of each other H, or straight chain or branched alkyl with 1 to 20 C-atoms, and k and l are each and independently 0, 1, 2, 3 or 4.

3. A birefringent reactive mesogen lens according to claim 1, wherein polymerizable liquid crystalline component (A) comprises at least one polymerizable mesogenic compound selected from formula II, and at least one polymerizable mesogenic compound selected from formula III,
P-Sp-(A.sup.21-Z.sup.21).sub.k-A.sup.22-(Z.sup.22-A.sup.23).sub.l-R.sup.0II
P-Sp-A.sup.31-Z.sup.31-A.sup.32-(Z.sup.32-A.sup.33).sub.l-R.sup.0III wherein P is a polymerizable group, Sp is a spacer group or a single bond, A.sup.21 to A.sup.33 are in each occurrence independently of one another an aryl-, heteroaryl-, heterocyclic- or alicyclic group, which in each case is optionally substituted by one or more identical or different groups L, Z.sup.21 and Z.sup.22 are in each occurrence independently from each other, O, S, CO, COO, OCO, SCO, COS, OCOO, CONR.sup.01, NR.sup.01CO, NR.sup.01CONR.sup.02, NR.sup.01COO, OCONR.sup.01, OCH.sub.2, CH.sub.2O, SCH.sub.2, CH.sub.2S, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, CF.sub.2CF.sub.2, or a single bond, Z.sup.31 and Z.sup.32 are in each occurrence independently from each other CHN, NCH, NN, CHCR.sup.01, CY.sup.01CY.sup.02, CC, CHCHCOO, OCOCHCH, and if both are present one of Z.sup.31 and Z.sup.32 can also denote O, S, CO, COO, OCO, SCO, COS, OCOO, CONR.sup.01, NR.sup.01CO, NR.sup.01CONR.sup.02, NR.sup.01COO, OCONR.sup.01, OCH.sub.2, CH.sub.2O, SCH.sub.2, CH.sub.2S, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, CF.sub.2CF.sub.2, or a single bond, L is, in case of multiple occurrences independently of one another, H, halogen, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, with up to 5 C atoms, R.sup.0 is H, optionally fluorinated alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, with up to 20 C atoms or is Y.sup.0 or P-Sp-, Y.sup.0 is F, Cl, CN, NO.sub.2, OCH.sub.3, OCN, SCN, optionally fluorinated alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, with up to 4 C atoms, or mono- oligo- or polyfluorinated alkyl or alkoxy with 1 to 4 C atoms, or mono- oligo- or polyfluorinated alkyl or alkoxy with 1 to 4 C atoms, Y.sup.01 and Y.sup.02 each, independently of one another, denote H, F, Cl or CN, R.sup.01 and R.sup.02 are independently of each other H, or straight chain or branched alkyl with 1 to 20 C-atoms, and k and l are each and independently 0, 1, 2, 3 or 4.

4. A birefringent reactive mesogen lens according to claim 2, wherein polymerizable liquid crystalline component (A) at least one polymerizable mesogenic compound selected from formulae II-1 to II-27, and at least one polymerizable mesogenic compound selected from formulae III-1 to III-12, ##STR00036## ##STR00037## ##STR00038## ##STR00039## ##STR00040## wherein P.sup.0 is, in case of multiple occurrences independently of one another, a polymerizable group, A.sup.0 is, in case of multiple occurrences independently of one another, 1,4-phenylene that is unsubstituted or substituted with 1, 2, 3 or 4 groups L, or trans-1,4-cyclohexylene, Z.sup.0 is, in case of multiple occurrences independently of one another, COO, OCO, CH.sub.2CH.sub.2, or a single bond, r is 0, 1, 2, 3 or 4, u and v are independently of each other 0, 1 or 2, w is 0 or 1, x and y are independently of each other 0 or identical or different integers from 1 to 12, and z is 0 or 1, with z being 0 if the adjacent x or y is 0, wherein the benzene and naphthalene rings can additionally be substituted with one or more identical or different groups L, and the parameter R.sup.0, Y.sup.0, R.sup.01, R.sup.02 and L have the same meanings as defined in claim 2.

5. A birefringent reactive mesogen lens according to claim 2, wherein polymerizable liquid crystalline component (A) comprises at least one polymerizable mesogenic compound selected from formulae IIIa to IIIc, and at least one polymerizable mesogenic compound selected from formulae IIIa to IIIh, ##STR00041## ##STR00042## wherein the parameter R.sup.0 is as defined in claim 2, and x and y are independently of each other integers from 1 to 12.

6. A birefringent reactive mesogen lens according to claim 1, wherein non-polymerizable component (B) comprises at least one non-polymerizable compound selected from catalysts, sensitizers, stabilizers, polymerization initiators, inhibitors, chain-transfer agents, lubricating agents, wetting agents, dispersing agents, hydrophobic agents, adhesive agents, flow improvers, defoaming agents, deaerators, diluents, reactive diluents, auxiliaries, colorants, and pigments.

7. A birefringent reactive mesogen lens according to claim 1, wherein the uncured polymerizable liquid crystalline medium exhibits a room temperature stability against crystallization for at least 1 hour.

8. A birefringent reactive mesogen lens according to claim 1, wherein said birefringent reactive mesogen lens has a birefringence in the range from 0.10 to 0.50.

9. A method of production of a birefringent reactive mesogen lens according to claim 1, said method comprising: providing a layer of a melt of the polymerizable liquid crystalline medium onto a substrate at elevated temperature providing an inverse lens mould on top of the layer of polymerizable liquid crystalline medium, annealing the polymerizable liquid crystalline medium in the mould at elevated temperature, cooling the mould, curing of the polymerizable liquid crystalline medium, and optionally removing the mould.

10. An electro-optical device comprising at least one birefringent reactive mesogen lens according to claim 1.

11. A birefringent reactive mesogen lens according to claim 5, wherein polymerizable liquid crystalline component (A) comprises at least one compound selected from formulae IIa to IIc and at least one compound selected from formulae IIIa to IIIe and IIIg.

12. A birefringent reactive mesogen lens according to claim 4, wherein (a) polymerizable liquid crystalline component (A) comprises one or more monoreactive mesogenic compounds selected from formulae II-1, II-6, II-7 III-1, III-2, III-3 and III-1, in concentration of from 5 to 50% by weight of the total medium, one or more direactive mesogenic compounds in a concentration in the range from 1 to 90% by weight of the total medium, and optionally one or more multireactive mesogenic compounds selected from formula II-27, in a concentration in the range from 0 to 25% by weight of the total medium; and (b) non-polymerizable component (B) comprises one or more non-polymerizable compounds in a total concentration of less than 5% by weight of the total medium.

13. A birefringent reactive mesogen lens according to claim 5, wherein (a) polymerizable liquid crystalline component (A) comprises one or more compounds of formula IIa, one or more compounds of formula IIc, and at least one compound selected from formulae IIIa to IIIh, and (b) non-polymerizable component (B) comprises one or more stabilizers, and one or more photoinitiators.

14. A birefringent reactive mesogen lens according to claim 1, wherein polymerizable liquid crystalline component (A) comprises one or more compounds selected from compounds (1)-(16): ##STR00043## ##STR00044##

15. A birefringent reactive mesogen lens according to claim 12, wherein the amount of the non-polymerizable component (B) is less than 2% by weight of the total medium.

16. A birefringent reactive mesogen lens according to claim 1, wherein said birefringent reactive mesogen lens has a birefringence (An) in the range from 0.15 to 0.45.

17. A birefringent reactive mesogen lens according to claim 1, wherein said birefringent reactive mesogen lens has a birefringence (An) in the range from 0.18 to 0.40.

18. A birefringent reactive mesogen lens according to claim 1, wherein said birefringent reactive mesogen lens has a yellowness index of lower than 11.

19. A birefringent reactive mesogen lens according to claim 1, wherein said birefringent reactive mesogen lens has a yellowness index of lower than 9.

20. A birefringent reactive mesogen lens according to claim 1, wherein said birefringent reactive mesogen lens has a yellowness index of lower than 7.

21. A birefringent reactive mesogen lens according to claim 1, wherein said non-polymerizable component (B) comprises one or more stabilizers in an amount up to 0.2% by weight of the total medium, and one or more photoinitiators in an amount of 0.001 to 5% by weight of the total medium.

22. A method of production of a birefringent reactive mesogen lens according to claim 1, said method comprising: filling a melt of the polymerizable liquid crystalline medium into a plano-convex lens mould at elevated temperature, annealing the polymerizable liquid crystalline medium in the mould at elevated temperature, cooling the mould, curing of the polymerizable liquid crystalline medium, and removing the mould.

23. A birefringent reactive mesogen lens obtainable from a polymerizable liquid crystalline medium consisting of: a polymerizable liquid crystalline component (A) consisting of one or more polymerizable mesogenic compounds, and a non-polymerizable component (B) consisting of one or more non-polymerizable compounds, wherein said liquid crystalline medium exhibits a homogeneous planar alignment throughout the whole lens, and wherein said lens has a plano-convex shape, and wherein said birefringent reactive mesogen lens has a birefringence (An) in the range from 0.18 to 0.40.

24. A birefringent reactive mesogen lens obtainable from a polymerizable liquid crystalline medium consisting of: a polymerizable liquid crystalline component (A) consisting of one or more polymerizable mesogenic compounds, and a non-polymerizable component (B) consisting of one or more non-polymerizable compounds, wherein said liquid crystalline medium exhibits a homogeneous planar alignment throughout the whole lens, and wherein said lens has a plano-convex shape, and wherein polymerizable liquid crystalline component (A) comprises one or more compounds selected from compounds (1), (2) and (4)-(16): ##STR00045## ##STR00046##

Description

DETAILED DESCRIPTION

(1) As mentioned above, the polymerizable liquid crystalline component A exclusively consists of at least one polymerizable mesogenic compound and are therefore the only polymerizable compounds present in the polymerizable liquid crystalline medium. The presence of other, e.g. non-mesogenic compounds is therefore excluded, which leads besides other favourable effects, e.g. to a significant increase of the birefringence.

(2) The polymerizable liquid-crystalline component A consists of at least one polymerizable mesogenic compound, preferably of a mixture of two or more polymerizable mesogenic compound, for example 2 to 30 polymerizable mesogenic compounds.

(3) The polymerizable mesogenic compounds of the polymerizable liquid crystalline component A are preferably selected from calamitic or discotic compounds demonstrating thermotropic or lyotropic liquid crystallinity, very preferably calamitic compounds, or mixtures of one or more types of these compounds having liquid-crystalline mesophases in a certain temperature range. These materials typically have good optical properties, like reduced chromaticity, and can be easily and quickly aligned into the desired orientation. The liquid crystals can be small molecules (i.e. monomeric compounds) or liquid-crystalline oligomers.

(4) In one embodiment, the polymerizable mesogenic compounds of the polymerizable liquid crystalline component A are preferably selected from one or more polymerizable mono-, di- or multireactive mesogenic compounds of formula I,
P-Sp-MG-R.sup.0I
wherein P is a polymerizable group, preferably an acryl, methacryl, vinyl, vinyloxy, propenyl ether, epoxy, oxetane or styrene group, Sp is a spacer group or a single bond, MG is a rod-shaped mesogenic group, which is preferably selected of formula M,
-(A.sup.21-Z.sup.21).sub.k-A.sup.22-(Z.sup.22-A.sup.23).sub.l-M A.sup.21 to A.sup.23 are in each occurrence independently of one another an aryl-, heteroaryl-, heterocyclic- or alicyclic group optionally being substituted by one or more identical or different groups L, preferably 1,4-cyclohexylene or 1,4-phenylene, 1,4 pyridine, 1,4-pyrimidine, 2,5-thiophene, 2,6-dithieno[3,2-b:2,3-d]thiophene, 2,7-fluorine, 2,6-naphtalene, 2,7-phenanthrene optionally being substituted by one or more identical or different groups L, Z.sup.21 and Z.sup.22 are in each occurrence independently from each other, O, S, CO, COO, OCO, SCO, COS, OCOO, CONR.sup.01, NR.sup.01CO, NR.sup.01CONR.sup.02, NR.sup.01COO, OCONR.sup.01, OCH.sub.2, CH.sub.2O, SCH.sub.2, CH.sub.2S, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, CF.sub.2CF.sub.2, CHN, NCH, NN, CHCR.sup.01, CY.sup.01CY.sup.02, CC, CHCHCOO, OCOCHCH, or a single bond, preferably COO, OCO, COO, OCO, OCH.sub.2, CH.sub.2O, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, CF.sub.2CF.sub.2, CC, CHCHCOO, OCOCHCH, or a single bond, L is, in case of multiple occurrence independently of one another, H, halogen, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 5 C atoms, preferably H, halogen or CN, alkyl or alkoxy with 1 to 5 C atoms, R.sup.0 is H, alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 20 C atoms more, preferably 1 to 15 C atoms which are optionally fluorinated, or is Y.sup.0 or P-Sp-, Y.sup.0 is F, Cl, CN, NO.sub.2, OCH.sub.3, OCN, SCN, optionally fluorinated alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 4 C atoms, or mono- oligo- or polyfluorinated alkyl or alkoxy with 1 to 4 C atoms, preferably F, Cl, CN, NO.sub.2, OCH.sub.3, or mono- oligo- or polyfluorinated alkyl or alkoxy with 1 to 4 C atoms, Y.sup.01 and Y.sup.02 each, independently of one another, denote H, F, Cl or CN. R.sup.01 and R.sup.02 are independently of each other H, or straight chain or branched alkyl with 1 to 20 C-atoms, preferably 1 to 6 C-atoms, and k and l are each and independently 0, 1, 2, 3 or 4, preferably 0, 1 or 2, most preferably 1.

(5) Above and below, carbyl group denotes a mono- or polyvalent organic group containing at least one carbon atom which either contains no further atoms (such as, for example, CC) or optionally contains one or more further atoms, such as, for example, N, O, S, P, Si, Se, As, Te or Ge (for example carbonyl, etc.).

(6) Hydrocarbyl group denotes a carbyl group, which additionally contains one or more H atoms and optionally one or more heteroatoms, such as, for example, N, O, S, P, Si, Se, As, Te or Ge.

(7) Halogen denotes F, Cl, Br or I.

(8) A carbyl or hydrocarbyl group can be a saturated or unsaturated group. Unsaturated groups are, for example, aryl, alkenyl or alkinyl groups. A carbyl or hydrocarbyl group having more than 3 C atoms can be straight chain, branched and/or cyclic and may contain spiro links or condensed rings.

(9) Above and below, the terms alkyl, aryl, heteroaryl, etc., also encompass polyvalent groups, for example alkylene, arylene, heteroarylene, etc. The term aryl denotes an aromatic carbon group or a group derived there from. The term heteroaryl denotes aryl in accordance with the above definition containing one or more heteroatoms.

(10) Preferred carbyl and hydrocarbyl groups are optionally substituted alkyl, alkenyl, alkinyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy having 1 to 40, preferably 1 to 25, particularly preferably 1 to 18 C atoms, optionally substituted aryl or aryloxy having 6 to 40, preferably 6 to 25 C atoms, or optionally substituted alkylaryl, arylalkyl, alkylaryloxy, arylalkyloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy having 6 to 40, preferably 6 to 25 C atoms.

(11) Further preferred carbyl and hydrocarbyl groups are C.sub.1-C.sub.40 alkyl, C.sub.2-C.sub.40 alkenyl, C.sub.2-C.sub.40 alkinyl, C.sub.3-C.sub.40 allyl, C.sub.4-C.sub.40 alkyldienyl, C.sub.4-C.sub.40 polyenyl, C.sub.6-C.sub.40 aryl, C.sub.6-C.sub.40 alkylaryl, C.sub.6-C.sub.40 arylalkyl, C.sub.6-C.sub.40 alkylaryloxy, C.sub.6-C.sub.40 arylalkyloxy, C.sub.2-C.sub.40 heteroaryl, C.sub.4-C.sub.40 cycloalkyl, C.sub.4-C.sub.40 cycloalkenyl, etc. Particular preference is given to C.sub.1-C.sub.22 alkyl, C.sub.2-C.sub.22 alkenyl, C.sub.2-C.sub.22 alkinyl, C.sub.3-C.sub.22 allyl, C.sub.4-C.sub.22 alkyldienyl, C.sub.6-C.sub.12 aryl, C.sub.6-C.sub.20 arylalkyl and C.sub.2-C.sub.20 heteroaryl.

(12) Further preferred carbyl and hydrocarbyl groups are straight-chain, branched or cyclic alkyl radicals having 1 to 40, preferably 1 to 25 C atoms, which are unsubstituted or mono- or polysubstituted by F, Cl, Br, I or CN and in which one or more non-adjacent CH.sub.2 groups may each be replaced, independently of one another, by C(R.sup.x)C(R.sup.x), CC, N(R.sup.x), O, S, CO, COO, OCO, OCOO in such a way that O and/or S atoms are not linked directly to one another.

(13) R.sup.x preferably denotes H, halogen, a straight-chain, branched or cyclic alkyl chain having 1 to 25 C atoms, in which, in addition, one or more non-adjacent C atoms may be replaced by O, S, CO, COO, OCO, OCOO, and in which one or more H atoms may be replaced by fluorine, an optionally substituted aryl or aryloxy group having 6 to 40 C atoms or an optionally substituted heteroaryl or heteroaryloxy group having 2 to 40 C atoms.

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

(15) Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, etc.

(16) Preferred alkinyl groups are, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, octynyl, etc.

(17) Preferred alkoxy groups are, for example, methoxy, ethoxy, 2-methoxyethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy, 2-methylbutoxy, n-pentoxy, n-hexoxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, n-undecyloxy, n-dodecyloxy, etc.

(18) Preferred amino groups are, for example, dimethylamino, methylamino, methylphenylamino, phenylamino, etc.

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

(20) Particular preference is given to mono-, bi- or tricyclic aryl groups having 6 to 25 C atoms and mono-, bi- or tricyclic heteroaryl groups having 2 to 25 C atoms, which optionally contain fused rings and are optionally substituted. Preference is furthermore given to 5-, 6- or 7-membered aryl and heteroaryl groups, in which, in addition, one or more CH groups may be replaced by N, S or O in such a way that O atoms and/or S atoms are not linked directly to one another.

(21) Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl, [1,1:3,1]-terphenyl-2-yl, naphthyl, anthracene, binaphthyl, phenanthrene, pyrene, dihydropyrene, chrysene, perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene, etc.

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

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

(24) The (non-aromatic) alicyclic and heterocyclic groups can be monocyclic, i.e. contain only one ring (such as, for example, cyclohexane), or polycyclic, i.e. contain a plurality of rings (such as, for example, decahydronaphthalene or bicyclooctane). Particular preference is given to saturated groups. Preference is furthermore given to mono-, bi- or tricyclic groups having 3 to 25 C atoms, which optionally contain fused rings and are optionally substituted. Preference is furthermore given to 5-, 6-, 7- or 8-membered carbocyclic groups in which, in addition, one or more C atoms may be replaced by Si and/or one or more CH groups may be replaced by N and/or one or more non-adjacent CH.sub.2 groups may be replaced by O and/or S.

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

(26) The aryl, heteroaryl, carbyl and hydrocarbyl radicals optionally have one or more substituents, which are preferably selected from the group comprising silyl, sulfo, sulfonyl, formyl, amine, imine, nitrile, mercapto, nitro, halogen, C.sub.1-12 alkyl, C.sub.6-12 aryl, C.sub.1-12 alkoxy, hydroxyl, or combinations of these groups.

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

(28) Preferred substituents, also referred to as L below, are, for example, F, Cl, Br, I, OH, CN, NO.sub.2, NCO, NCS, OCN, SCN, C(O)N(R.sup.x).sub.2, C(O)Y.sup.1, C(O)R.sup.x, C(O)OR.sup.x, N(R.sup.x).sub.2, in which R.sup.x has the above-mentioned meaning, and Y.sup.1 denotes halogen, optionally substituted silyl, optionally substituted aryl or heteroaryl having 4 to 40, preferably 4 to 20 ring atoms, and straight-chain or branched alkyl, alkenyl, alkinyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, in which one or more H atoms may optionally be replaced by F or Cl.

(29) Substituted silyl or aryl preferably means substituted by halogen, CN, R.sup.0, OR.sup.0, COR.sup.0, COOR.sup.0, OCOR.sup.0 or OCOOR.sup.0, in which R.sup.0 has the above-mentioned meaning.

(30) Particularly preferred substituents L are, for example, F, Cl, CN, NO.sub.2, CH.sub.3, C.sub.2H.sub.5, OCH.sub.3, OC.sub.2H.sub.5, COCH.sub.3, COC.sub.2H.sub.5, COOCH.sub.3, COOC.sub.2H.sub.5, CF.sub.3, OCF.sub.3, OCHF.sub.2, OC.sub.2F.sub.5, furthermore phenyl.

(31) In the formula shown above and below, a substituted phenylene ring

(32) ##STR00001##
is preferably

(33) ##STR00002##
in which L has, on each occurrence identically or differently, one of the meanings given above and below, and is preferably F, Cl, CN, NO.sub.2, CH.sub.3, C.sub.2H.sub.5, C(CH.sub.3).sub.3, CH(CH.sub.3).sub.2, CH.sub.2CH(CH.sub.3)C.sub.2H.sub.5, OCH.sub.3, OC.sub.2H.sub.5, COCH.sub.3, COC.sub.2H.sub.5, COOCH.sub.3, COOC.sub.2H.sub.5, CF.sub.3, OCF.sub.3, OCHF.sub.2, OC.sub.2F.sub.5 or P-Sp-, very preferably F, Cl, CN, CH.sub.3, C.sub.2H.sub.5, OCH.sub.3, COCH.sub.3, OCF.sub.3 or P-Sp-, most preferably F, Cl, CH.sub.3, OCH.sub.3, COCH.sub.3 or OCF.sub.3.

(34) The polymerizable group P is preferably selected from groups containing a CC double bond or CC triple bond, and groups which are suitable for polymerization with ring opening, such as, for example, oxetane or epoxide groups.

(35) Very preferably the polymerizable group P is selected from the group consisting of CH.sub.2CW.sup.1COO, CH.sub.2CW.sup.1CO,

(36) ##STR00003##
CH.sub.2CW.sup.2(O).sub.k3, CW.sup.1CHCO(O).sub.k3, CW.sup.1CHCONH, CH.sub.2CW.sup.1CONH, CH.sub.3CHCHO, (CH.sub.2CH).sub.2CHOCO, (CH.sub.2CHCH.sub.2).sub.2CHOCO, (CH.sub.2CH).sub.2CHO, (CH.sub.2CHCH.sub.2).sub.2N, (CH.sub.2CHCH.sub.2).sub.2NCO, CH.sub.2CW.sup.1CONH, CH.sub.2CH(COO).sub.k1-Phe-(O).sub.k2, CH.sub.2CH(CO).sub.k1-Phe-(O).sub.k2, Phe-CHCH, in which W.sup.1 denotes H, F, Cl, CN, CF.sub.3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH.sub.3, W.sup.2 denotes H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W.sup.3 and W.sup.4 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 being defined above but being different from P-Sp, and 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 is an integer from 1 to 10.

(37) Particularly preferred groups P are CH.sub.2CHCOO, CH.sub.2C(CH.sub.3)COO, CH.sub.2CFCOO, CH.sub.2CH, CH.sub.2CHO, (CH.sub.2CH).sub.2CHOCO, (CH.sub.2CH).sub.2CHO,

(38) ##STR00004##
in particular vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide, most preferably acrylate or methacrylate.

(39) In a further preferred embodiment of the invention, the all polymerizable compounds and sub-formulae thereof contain, instead of one or more radicals P-Sp-, one or more branched radicals containing two or more polymerizable groups P (multireactive polymerizable radicals). Suitable radicals of this type, and polymerizable compounds containing them, are described, for example, in U.S. Pat. No. 7,060,200 B1 or US 2006/0172090 A1. Particular preference is given to multireactive polymerizable radicals selected from the following formulae:
X-alkyl-CHP.sup.1CH.sub.2CH.sub.2P.sup.2I*a
X-alkyl-C(CH.sub.2P.sup.1)(CH.sub.2P.sup.2)CH.sub.2P.sup.3I*b
X-alkyl-CHP.sup.1CHP.sup.2CH.sub.2P.sup.3I*c
X-alkyl-C(CH.sub.2P.sup.1)(CH.sub.2P.sup.2)C.sub.aaH.sub.2aa+1I*d
X-alkyl-CHP.sup.1CH.sub.2P.sup.2I*e
X-alkyl-CHP.sup.1P.sup.2I*f
X-alkyl-CP.sup.1P.sup.2C.sub.aaH.sub.2aa+1I*g
X-alkyl-C(CH.sub.2P.sup.1)(CH.sub.2P.sup.2)CH.sub.2OCH.sub.2C(CH.sub.2P.sup.3)(CH.sub.2P.sup.4)CH.sub.2P.sup.5I*h
X-alkyl-CH((CH.sub.2).sub.aaP.sup.1)((CH.sub.2).sub.bbP.sup.2)I*i
X-alkyl-CHP.sup.1CHP.sup.2C.sub.aaH.sub.2aa+1I*k
in which
alkyl denotes a single bond or straight-chain or branched alkylene having 1 to 12 C atoms, in which one or more non-adjacent CH.sub.2 groups may each be replaced, independently of one another, by C(R.sup.x)C(R.sup.x), CC, N(R.sup.x), O, S, CO, COO, OCO, OCOO in such a way that O and/or S atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by F, Cl or CN, where IV has the above-mentioned meaning and preferably denotes R.sup.0 as defined above,
aa and bb each, independently of one another, denote 0, 1, 2, 3, 4, 5 or 6, X has one of the meanings indicated for X, and P.sup.1-5 each, independently of one another, have one of the meanings indicated above for P.

(40) Preferred spacer groups Sp are selected from the formula Sp-X, so that the radical P-Sp- conforms to the formula P-Sp-X, where Sp denotes alkylene having 1 to 20, preferably 1 to 12 C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN and in which, in addition, one or more non-adjacent CH.sub.2 groups may each be replaced, independently of one another, by O, S, NH, NR.sup.01, SiR.sup.01R.sup.02, CO, COO, OCO, OCOO, SCO, COS, NR.sup.01COO, OCONR.sup.01, NR.sup.01CONR.sup.01, CHCH or CC in such a way that O and/or S atoms are not linked directly to one another, X denotes O, S, CO, COO, OCO, OCOO, CONR.sup.01, NR.sup.01CO, NR.sup.01CONR.sup.01, OCH.sub.2, CH.sub.2O, SCH.sub.2, CH.sub.2S, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, CF.sub.2CF.sub.2, CHN, NCH, NN, CHCR.sup.01, CY.sup.01CY.sup.02, CC, CHCHCOO, OCOCHCH or a single bond, R.sup.01 and R.sup.02 each, independently of one another, denote H or alkyl having 1 to 12 C atoms, and Y.sup.01 and Y.sup.02 each, independently of one another, denote H, F, Cl or CN. X is preferably O, S, CO, COO, OCO, OCOO, CONR.sup.0, NR.sup.01CO, NR.sup.01CONR.sup.01 or a single bond.

(41) Typical spacer groups Sp are, for example, (CH.sub.2).sub.p1, (CH.sub.2CH.sub.2O).sub.q1CH.sub.2CH.sub.2, CH.sub.2CH.sub.2SCH.sub.2CH.sub.2, CH.sub.2CH.sub.2NHCH.sub.2CH.sub.2 or (SiR.sup.02R.sup.02O).sub.p1, in which p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R.sup.01 and R.sup.02 have the above-mentioned meanings.

(42) Particularly preferred groups X-Sp- are (CH.sub.2).sub.p1, O(CH.sub.2).sub.p1, OCO(CH.sub.2).sub.p1, OCOO(CH.sub.2).sub.p1.

(43) 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, ethylene-N-methyliminoethylene, 1-methylalkylene, ethenylene, propenylene and butenylene.

(44) In another embodiment, the polymerizable liquid crystalline component A comprises at least one polymerizable mono-, di- or multireactive mesogenic compound selected of formula II, and at least one polymerizable mono-, di- or multireactive mesogenic compound selected of formula III,
P-Sp-(A.sup.21-Z.sup.21).sub.k-A.sup.22-(Z.sup.22-A.sup.23).sub.l-R.sup.0II
P-Sp-A.sup.31-Z.sup.31-A.sup.32-(Z.sup.32-A.sup.33).sub.l-R.sup.0III
wherein P is a polymerizable group, preferably an acryl, methacryl, vinyl, vinyloxy, propenyl ether, epoxy, oxetane or styrene group, Sp is a spacer group or a single bond, A.sup.21 to A.sup.33 are in each occurrence independently of one another an aryl-, heteroaryl-, heterocyclic- or alicyclic group optionally being substituted by one or more identical or different groups L, preferably 1,4-cyclohexylene or 1,4-phenylene, 1,4 pyridine, 1,4-pyrimidine, 2,5-thiophene, 2,6-dithieno[3,2-b:2,3-d]thiophene, 2,7-fluorine, 2,6-naphtalene, 2,7-phenanthrene optionally being substituted by one or more identical or different groups L, Z.sup.21 and Z.sup.22 are in each occurrence independently from each other, O, S, CO, COO, OCO, SCO, COS, OCOO, CONR.sup.01, NR.sup.01CO, NR.sup.01CONR.sup.02, NR.sup.01COO, OCONR.sup.01, OCH.sub.2, CH.sub.2O, SCH.sub.2, CH.sub.2S, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, CF.sub.2CF.sub.2, or a single bond, preferably COO, OCO, COO, OCO, OCH.sub.2, CH.sub.2O, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, CF.sub.2CF.sub.2, or a single bond, Z.sup.31 and Z.sup.32 are in each occurrence independently from each other CHN, NCH, NN, CHCR.sup.01, CY.sup.01CY.sup.02, CC, CHCHCOO, OCOCHCH, and if l>0, one of Z.sup.31 and Z.sup.32 can also denote O, S, CO, COO, OCO, SCO, COS, OOCO, CONR.sup.01, NR.sup.01CO, NR.sup.01CONR.sup.02, NR.sup.01COO, OCONR.sup.01, OCH.sub.2, CH.sub.2O, SCH.sub.2, CH.sub.2S, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, CF.sub.2CF.sub.2, or a single bond, L is, in case of multiple occurrence independently of one another, H, halogen, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 5 C atoms, preferably H, halogen or CN, alkyl or alkoxy with 1 to 5 C atoms, R.sup.0 is H, alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 20 C atoms more, preferably 1 to 15 C atoms which are optionally fluorinated, or is Y.sup.0 or P-Sp-, Y.sup.0 is F, Cl, CN, NO.sub.2, OCH.sub.3, OCN, SCN, optionally fluorinated alkylcarbonyl, alkoxycarbonyl, alkylcarbonyl-oxy or alkoxycarbonyloxy with 1 to 4 C atoms, or mono- oligo- or polyfluorinated alkyl or alkoxy with 1 to 4 C atoms, preferably F, Cl, CN, NO.sub.2, OCH.sub.3, or mono- oligo- or polyfluorinated alkyl or alkoxy with 1 to 4 C atoms, Y.sup.01 and Y.sup.02 each, independently of one another, denote H, F, Cl or CN. R.sup.01 and R.sup.02 are independently of each other H, or straight chain or branched alkyl with 1 to 20 C-atoms, preferably 1 to 6 C-atoms, and k and l are each and independently 0, 1, 2, 3 or 4, preferably 0, 1 or 2, most preferably 1.

(45) Preferably, the polymerizable liquid crystalline component A comprises at least one polymerizable mono-, di- or multireactive mesogenic compound selected of formulae II-1 to II-27,

(46) ##STR00005## ##STR00006## ##STR00007##
and at least one polymerizable mono-, di- or multireactive mesogenic compounds selected of formula III-1 to III-12,

(47) ##STR00008## ##STR00009##
wherein P.sup.0 is, in case of multiple occurrences independently of one another, a polymerizable group, preferably an acryl, methacryl, oxetane, epoxy, vinyl, vinyloxy, propenyl ether or styrene group, A.sup.0 is, in case of multiple occurrences independently of one another, 1,4-phenylene that is optionally substituted with 1, 2, 3 or 4 groups L, or trans-1,4-cyclohexylene, Z.sup.0 is, in case of multiple occurrences independently of one another, COO, OCO, CH.sub.2CH.sub.2, or a single bond, Z.sup.1 is in each occurrence independently from each other O, S, CO, COO, OCO, SCO, COS, OCOO, CONR.sup.01, NR.sup.01CO, NR.sup.01CONR.sup.02, NR.sup.01COO, OCONR.sup.01, OCH.sub.2, CH.sub.2O, SCH.sub.2, CH.sub.2S, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, CF.sub.2CF.sub.2, CHN, NCH, NN, CHCR.sup.01, Y.sup.01CY.sup.02, CC, CHCHCOO, OCOCHCH, or a single bond, Z.sup.2 is CHN, NCH, NN, CHCR.sup.01, CY.sup.01CY.sup.02, CC, CHCHCOO, OCOCHCH, and if present at least twice, at least one of Z.sup.1 can also denote O, S, O, COO, OCO, SCO, COS, OCOO, CONR.sup.01, NR.sup.01CO, NR.sup.01CONR.sup.02, NR.sup.01COO, OCONR.sup.01, OCH.sub.2, CH.sub.2O, SCH.sub.2, CH.sub.2S, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, CF.sub.2CF.sub.2, or a single bond, r is 0, 1, 2, 3 or 4, preferably 0, 1 or 2, u and v are independently of each other 0, 1 or 2, w is 0 or 1, x and y are independently of each other 0 or identical or different integers from 1 to 12, z is 0 or 1, with z being 0 if the adjacent x or y is 0, and
the parameter R.sup.0, Y.sup.0, R.sup.01, R.sup.02 and L have the same meanings as given above in formula I. wherein

(48) More preferably, the polymerizable liquid crystalline component A comprises at least one polymerizable mono-, di- or multireactive mesogenic compound selected formula IIa to IIc,

(49) ##STR00010##
and at least one polymerizable mesogenic compound of the following formulae IIIa to IIIh,

(50) ##STR00011##
wherein the parameter R.sup.0 has the same meaning as given above in formula I, x and y are independently of each other integers from 1 to 12.

(51) Especially preferably the polymerizable mesogenic compounds of the polymerizable liquid crystalline component A are selected from at least one compound of formulae IIa to IIc and at least one compound selected from the formulae IIIa to IIIe and IIIg.

(52) In a preferred embodiment, the non-polymerizable component B comprises one or more stabilizers or inhibitors to prevent undesired spontaneous polymerization, preferably in an amount of 0 to 0.1% by weight of the total medium, very preferably 0 to 0.2% by weight of the total medium, for example selected from the commercially available Irganox series (Ciba AG), like Irganox 1076.

(53) Polymerization of the polymerizable liquid crystalline medium is preferably carried out in the presence of a polymerization initiator. For this purpose the non-polymerizable component (B) preferably comprises one or more initiators. For example, when polymerizing by means of UV light, a photoinitiator can be used that decomposes under UV irradiation to produce free radicals or ions that start the polymerization reaction. For polymerizing acrylate or methacrylate groups preferably, a radical photoinitiator is used. For polymerizing vinyl, epoxide, or oxetane groups preferably, a cationic photoinitiator is used. It is also possible to use a thermal polymerization initiator that decomposes when heated to produce free radicals or ions that start the polymerization. Suitable for free-radical polymerization are, for example, the commercially available photoinitiators Irgacure651, Irgacure184, Irgacure907, Irgacure369 or Darocure1173 (Ciba AG). If an initiator is employed, its proportion is preferably 0.001 to 5% by weight of the total medium, particularly preferably 0.001 to 1% by weight of the total medium. A typical cationic photoinitiator is for example UVI 6974 (Union Carbide).

(54) Alternatively, component B can also comprise a dichroic or liquid crystalline photoinitiator as disclosed for example in EP 1 388 538 A1.

(55) As with the common photo initiators, a dichroic photo initiator dissociates when exposed to the correct wavelength and the formed radicals will initiate polymerization of monomers. The dichroic photo initiator has the property that the light absorption is dependent on the molecular orientation of the molecule. The dichroic photo initiators selectively dissociate when aligned with the electric field vector of the incoming light.

(56) Very preferred dichroic photoinitiators of component B are selected from the group consisting of the following formulae:

(57) ##STR00012##
wherein L is H or F, R is alkyl or alkoxy with 1 to 12 C-atoms, and R and R are selected from alkyl or alkoxy with 1 to 6 C-atoms, very preferably from methyl, ethyl or propyl.

(58) The concentration of the polymerization initiator in the polymerizable liquid crystalline medium is preferably from 0.01 to 10% by weight of the total medium, very preferably from 0.05 to 6% by weight of the total medium.

(59) Further preferred is a component B comprising one or more surfactants, which promote a specific surface alignment of the LIQUID CRYSTALLINE molecules. Suitable surfactants are described for example in J. Cognard, Mol. Cryst. Liq. Cryst. 78, Supplement 1, 1-77 (1981). Preferred aligning agents for planar alignment are for example non-ionic surfactants, preferably fluorocarbon surfactants such as the commercially available Fluorad FC-171 (from 3M Co.) or Zonyl FSN (from DuPont), multiblock surfactants as described in GB 2 383 040 or polymerizable surfactants as described in EP 1 256 617 A1.

(60) The non-polymerizable component may also comprises one or more dyes having an absorption maximum adjusted to the wavelength of the radiation used for polymerization, in particular UV dyes like e.g. 4,4-azoxy anisole or Tinuvin dyes (from Ciba AG).

(61) Said non-polymerizable component B can additionally comprise one or more additional components like for example catalysts, sensitizers, stabilizers, inhibitors, chain-transfer agents, lubricating agents, wetting agents, dispersing agents, hydrophobing agents, adhesive agents, flow improvers, defoaming agents, deaerators, diluents, reactive diluents, auxiliaries, colourants or pigments.

(62) As mentioned above, a suitable polymerizable liquid crystalline medium for a birefringent RM lens according to the present invention consists of several compounds, preferably of 2 to 30, more preferably of 3 to 20 and most preferably of 4 to 10 compounds. These compounds are mixed in conventional way. As a rule, the required amount of the compound used in the smaller amount is dissolved in the compound used in the greater amount. In case the temperature is above the clearing point of the compound used in the higher concentration, it is particularly easy to observe completion of the process of dissolution. It is, however, also possible to prepare the media by other conventional ways, e.g. using so-called pre-mixtures, which can be e.g. homologous or eutectic mixtures of compounds or using so-called multi-bottle-systems, the constituents of which are ready to use mixtures themselves.

(63) Preferably the amount of the polymerizable liquid-crystalline component A in the medium is more than 95% by weight of the total medium, more preferably more than 97% by weight of the total medium and even more preferably more than 98% by weight of the total medium.

(64) Preferably, the amount of the non-polymerizable component B is less than 5% by weight of the total medium, more preferably less than 3% by weight of the total medium and even more preferably less than 2% by weight of the total medium.

(65) The polymerizable liquid-crystalline component A preferably comprises one or more compounds of formula I in a total concentration of more than 95% by weight of the total medium, more preferably more than 97% by weight of the total medium and even more preferably more than 98% by weight of the total medium, preferably these compounds are selected from the group of the sub formulae II-1, II-6, II-7, II-27, III-1, III-2, III-3 and III-11, and
the non-polymerizable component B preferably comprises one or more non-polymerizable compounds in a total concentration of less than 5% by weight of the total medium, more preferably less than 3% by weight of the total medium and even more preferably less than 2% by weight of the total medium, preferably these compounds are selected from selected from stabilizers alignment additives, surfactants and photoinitiators.

(66) More preferably, the polymerizable liquid-crystalline component A preferably comprises preferably one, two, three or more monoreactive mesogenic compounds, preferably selected from formulae II-1, II-6, II-7 III-1, III-2, III-3 and III-1, preferably in concentration in the range from 5 to 50% by weight of the total medium, more preferably 10 to 40% by weight of the total medium, even more preferably 15 to 30% by weight of the total medium, and preferably one, two, three or more direactive mesogenic compounds, preferably in concentration in the range from 1 to 90% by weight of the total medium, more preferably 5 to 80% by weight of the total medium, even more preferably 10 to 70% by weight of the total medium, and optionally one, two, three or more multireactive mesogenic compounds, preferably selected from formula II-27, preferably in concentration in the range from 0 to 25% by weight of the total medium, more preferably 0 to 20% by weight of the total medium, even more preferably 0 to 10% by weight of the total medium, and
the non-polymerizable component B preferably comprises one or more non-polymerizable compounds in a total concentration of less than 5% by weight of the total medium, more preferably less than 3% by weight of the total medium and even more preferably less than 2% by weight of the total medium, preferably these compounds are selected from stabilizers alignment additives, surfactants and photoinitiators.

(67) Even more preferably, the polymerizable liquid-crystalline component A preferably comprises, one or more compounds of formula IIa, in particular wherein R.sup.0 denotes alkoxy or CN, and x is 6, preferably in concentration in the range from 10 to 60% by weight of the total medium, in particular 15-50 one or more compounds of formula IIc, in particular wherein x and y denotes each both 3 or both 6, preferably in concentration in the range from 5 to 60% by weight of the total medium, in particular 10-50% by weight of the total medium, and at least one compound selected from the group of compounds of formulae IIIa to IIIh, preferably in concentration in the range from 1 to 60% by weight of the total medium, in particular 1 to 30% by weight of the total medium, and
the non-polymerizable component B preferably comprises one or more stabilizers, preferably selected from the commercially available Irganox series (Ciba AG), like Irganox 1076, preferably in an amount of 0 to 0.1% by weight of the total medium, very preferably 0 to 0.2% by weight of the total medium, and one or more photoinitiators, preferably selected from the commercially available photoinitiators Irgacure651, Irgacure184, Irgacure907, Irgacure369 or Darocure1173 (Ciba AG), preferably in an amount of 0.001 to 5% by weight of the total medium, particularly preferably 0.001 to 1% by weight of the total medium.

(68) The general methods for the preparation of birefringent RM lens according to this invention are known to the ordinary expert and can be performed for example as described in JP2012-137616 A1.

(69) In a preferred embodiment, a method of production comprises the steps of filling a melt of the polymerizable liquid crystalline medium into a plano-convex lens mould at elevated temperature, annealing the polymerizable liquid crystalline medium in the mould at elevated temperature, cooling the mould, curing of the polymerizable liquid crystalline medium, and optionally removing the mould.

(70) In another preferred embodiment, the method comprises the steps of providing a layer of a melt of the polymerizable liquid crystalline medium onto a substrate at room temperature or elevated temperature, providing an inverse lens mould on top of the coated polymerizable liquid crystalline medium, annealing the polymerizable liquid crystalline medium in the mould at elevated temperature, cooling the mould, curing of the polymerizable liquid crystalline medium, and optionally removing the mould.

(71) The substrate used for the birefringent RM lens the present invention can be any substrate as usually used for liquid crystal devices, displays, optical parts, and optical films. It is not limited to any specific substrates as long as it has enough heat resistance to endure the heating after coating the melted birefringent RM lens material of the present invention or the heating during the liquid crystal device manufacturing.

(72) Examples of such substrates, which also can be the material of choice for the lens mould, are a glass substrate, metal substrate, ceramic substrate, and plastic substrate. Particularly when the substrate is the organic material, the examples of substrate materials are cellulose derivatives, polyolefin, polyester, polyolefin, polycarbonate, polyacrylate, poly-allylate, polyether sulfon, polyimide, poly-phenylene sulfide, poly-phenylene ether, nylon, and polystyrene. Among them, polyester, polystyrene, polyolefin, cellulose derivatives, polyallylate, and polycarbonate are preferred.

(73) As a coating method to obtain the birefringent RM lens of the present invention, the well-known and commonly used method can be used. The examples are an applicator method, bar coating method, spin coating method, gravure print method, flexographic method, inkjet method, die coating method, cap coating method, and the dipping method.

(74) The preferred coating temperature is dependent, inter alia, on the melting point of the polymerizable liquid-crystalline medium.

(75) Preferably, the coated film of the polymerizable liquid crystalline medium exhibit a room temperature a suitable stability against crystallization for at least 1 hour, more preferably for at least 3 hours, and most preferably for at least 16 hours.

(76) The thickness of the coated layer of the melt of the polymerizable liquid crystalline medium is dependent, inter alia, on the thickness of used lens mould or the preferred lens thickness in dependence of the value for the birefringence of the RM lens.

(77) Initial alignment (e.g. planar alignment) of the polymerizable liquid crystalline medium can be achieved by annealing the polymerizable liquid crystalline medium before polymerization, or also by application of an alignment layer, by applying a magnetic or electric field to the coated polymerizable liquid crystalline medium, or by the addition of surface-active compounds to the polymerizable liquid crystalline medium. Reviews of alignment techniques are given for example by I. Sage in Thermotropic Liquid Crystals, edited by G. W. Gray, John Wiley & Sons, 1987, pages 75-77; and by T. Uchida and H. Seki in Liquid CrystalsApplications and Uses Vol. 3, edited by B. Bahadur, World Scientific Publishing, Singapore 1992, pages 1-63. A review of alignment materials and techniques is given by J. Cognard, Mol. Cryst. Liq. Cryst. 78, Supplement 1 (1981), pages 1-77.

(78) It is also possible to apply an alignment layer onto the substrate and provide the polymerizable liquid crystalline medium onto this alignment layer. Suitable alignment layers are known in the art, like for example rubbed polyimide or alignment layers prepared by photo alignment as described in U.S. Pat. No. 5,602,661, U.S. Pat. No. 5,389,698 or U.S. Pat. No. 6,717,644.

(79) In detail, suitable alignment treatments are for example a stretch treatment, rubbing treatment, polarized UV-visible light irradiation treatment, and the ion beam treatment. In the case that the alignment film is used, the well-known and commonly used alignment film can be used.

(80) Detailed examples of such the alignment film are polyimide, polysiloxane, polyamide, polyvinyl alcohol, polycarbonate, polystyrene, poly-phenylene ether, poly-allylate, polyethylene terephthalate, polyether sulfone, epoxy resin, epoxy acrylate resin, acryl resin, cumarine compound, chalcone compound, cinnamate compound, fulgide compound, anthraquinone compound, azo compound, and aryl ethane compound. For the compounds, which are alignment-processed by the methods beside the rubbing treatment, the use of the light alignment material is desirable.

(81) Forming a birefringent RM lens of the present invention can be carried out by polymerizing polymerizable liquid crystalline medium into a lens shape by using a photo mask. When the photo mask is used, the photo mask is designed in such the manner that the desired lens shape is obtained after the polymerization of the birefringent RM lens material or polymerizable liquid crystalline medium.

(82) However, the coated film of the polymerizable liquid crystalline medium is preferably covered with a lens mould. When the mould is used, the coating film of the birefringent RM lens material or polymerizable liquid crystalline medium is covered with a plano-convex lens mould having preferably the same refractive index as the ordinary refractive index (n.sub.o) of the polymerizable liquid crystalline medium of the present invention, and the polymerization is carried out while being covered.

(83) Polymerization is achieved for example by exposing the polymerizable liquid crystalline medium to actinic radiation. Actinic radiation means irradiation with light, like UV light, IR light or visible light, irradiation with X-rays or gamma rays, or irradiation with high energy particles, such as ions or electrons. Preferably, polymerization is carried out by. As a source for actinic radiation, for example a single UV lamp or a set of UV lamps can be used. When using a high lamp power the curing time can be reduced. Another possible source for actinic radiation is a laser, like for example a UV, IR or visible laser.

(84) When the polymerization is carried out by the UV irradiation, it is generally preferable to irradiate it with the UV ray having at most 390 nm wavelengths, and more preferably with the light having the wavelength of 250 to 370 nm, in concrete. However, in the case that the decomposition of the polymerizable liquid crystal composition is caused by the UV ray having at most 390 nm, it may be preferable to carry out the polymerization treatment with the UV ray having at least 390 nm. This light is preferably diffused light, however in case, a dichroic photo initiator is present, it is preferred to use polarized light.

(85) The curing time is dependent, inter alia, on the reactivity of the polymerizable liquid-crystalline medium, the thickness of the coated layer, the type of polymerization initiator and the power of the UV lamp. The curing time is preferably 5 minutes, very preferably 3 minutes, most preferably 1 minute.

(86) A suitable UV radiation power is preferably in the range from 5 to 200 mWcm.sup.2, more preferably in the range from 10 to 175 mWcm.sup.2 and most preferably in the range from 20 to 150 mWcm.sup.2.

(87) In connection with the applied UV radiation and as a function of time, a suitable UV dose is preferably in the range from 25 to 7200 mJcm.sup.2 more preferably in the range from 500 to 7200 mJcm.sup.2 and most preferably in the range from 1000 to 7200 mJcm.sup.2.

(88) The curing temperature is desirably a lower temperature than the temperature at which the inhomogeneous polymerization is induced by heat, in addition to the consideration to the transition temperature from the liquid crystal phase to the isotropic phase of the polymerizable liquid crystal composition. Here, when the substrate made of the organic material exceeds the glass transition point, the thermal deformation of the substrate becomes severe.

(89) The preferred curing temperature range is between 10 to 70 C., more preferably between 15 to 50 C., and even more preferably between 20 to 30 C.

(90) A polymerizable liquid crystal medium preferably has a clearing point in the range from about 50 C. to about 150 C., especially up to about 100 C. or even 80 C.

(91) The optical retardation (()) of a RM lens as a function of the wavelength of the incident beam () is given by the following equation:
()=(2n.Math.d)/
wherein (n) is the birefringence of the RM lens, (d) is the thickness of the RM lens and k is the wavelength of the incident beam.

(92) According to Snellius law, the birefringence as a function of the direction of the incident beam is defined as
n=sin /sin
wherein sin is the incidence angle or the tilt angle of the optical axis in the film and sin is the corresponding reflection angle.

(93) Based on these laws, the birefringence and accordingly optical retardation depends on the thickness of a RM lens and the tilt angle of optical axis in the film (cf. Berek's compensator). Therefore, the skilled expert is aware that different optical retardations or different birefringence can be induced either by adjusting the orientation of the liquid-crystalline molecules in the RM lens or by adjusting the lens thickness.

(94) Preferably, the birefringence (n) of the RM lens in accordance with the present invention is preferably in the range from 0.10 to 0.50, more preferable in the range from 0.15 to 0.45 and even more preferable in the range from 0.18 to 0.40.

(95) The birefringence (n) was calculated using the following formula,
n=()/d,
wherein
() is retardation as explained above and (d) is the thickness of the RM lens as mentioned above. Above and below, the n values are given at a wavelength of =550 nm.

(96) The thickness of the RM lens obtained by the method according to the present invention is preferably in the range from 3 to 200 m, more preferable in the range from 3 to 100 m and even more preferable in the range from 3 to 30 m.

(97) The thickness of the RM lens is measured by making a scratch in the polymerized film and measuring the depth of the scratch with an Alpha step surface profileometer.

(98) The difference in retardation between 40 and +40 viewing angle expressed as a percentage of the on axis retardation obtained by the method according to the present invention is preferably less than 5%, more preferably less than 1% and even more preferably 0%

(99) Retardation is measured using a spectroscopic ellipsometer.

(100) The birefringent RM lens according to the present invention can be used in a wide variety of electro optical devices, such as autostereoscopic 3D displays, polarized light guide plates, optical drives (DVD, blue ray, CD), etc.

(101) The transmission of the birefringent RM lens at 550 nm is preferably higher than 85%, more preferably higher than 90%, and even more preferably higher than 93%. The transmission of the birefringent RM lens can be measured in a Hitachi 3310 UV-vis spectrometer.

(102) Yellowness index (b-value) of the birefringent RM lens is preferably lower than 11, more preferably lower than 9, and even more preferably lower than 7.

(103) The yellowness index or b-value in accordance with the CIE LAB colour scale is measured using a Konica Minolta CR300 colour camera, in reflection mode. In this test an empty PI glass cell measures at a b-value of 4.14 as a reference.

(104) Accordingly, in a preferred embodiment, the birefringent RM lens can be used in an autostereoscopic display device. Such device comprises a display panel on top of which is provided a lens arrangement comprising at least one birefringent RM lens.

(105) A suitable display panel according to the present invention is a liquid crystal (LCD), a plasma (PDP), an organic light emitting diode (OLED) or cathode ray tube (CRT) display panel, preferably a liquid crystal display. However, it will be apparent to those skilled in the art that alternative types of display panels may also be employed.

(106) The display panel has an array of display pixels for producing a display image and the display pixels are arranged in rows and columns. In a preferred embodiment, the preferred display pixel pitch is in the range 50 m to 1000 m.

(107) In a preferred embodiment of the present invention, a transparent coupling film is laminated between the front side of the display panel and said lens arrangement, which substantially couples the incident light of the display panel at an oblique angle to the lens arrangement. Preferably, this transparent coupling film has a prismatic grid structure.

(108) However, in the preferred embodiment, a plane transparent spacer sheet is laminated between the front side of the display panel and said lens arrangement.

(109) The lens arrangement enables an autostereoscopic image to be viewed. Therefore, each lens arrangement overlies a small group of display pixels in each row or column or at least one display pixel. The lens arrangement projects each display pixel or a group of display pixels in a different direction, to form the several different views. As the user's head moves from left to right, his/her eyes will receive different ones of the several views, in turn.

(110) In a preferred embodiment of the present invention, the lens arrangement in is a lenticular screen plate. A lenticular screen plate is defined by a one-dimensional periodic arrangement of a plurality of lenses, preferably a row of lenses extending parallel to one another. In this connection, the lenticular screen plate can be a cylindrical lens grid disc, elliptical lens grid disc or prismatic lens grid disc, preferably a cylindrical lens grid disc.

(111) The present invention is described above and below with particular reference to the preferred embodiments. It should be understood that various changes and modifications might be made therein without departing from the spirit and scope of the invention.

(112) Many of the compounds or mixtures thereof mentioned above and below are commercially available. All of these compounds are either known or can be prepared by methods which are 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 said reactions. Use may also be made here of variants which are known per se, but are not mentioned here.

(113) Unless the context clearly indicates otherwise, as used herein plural forms of the terms herein are to be construed as including the singular form and vice versa.

(114) Throughout this application, unless explicitly stated otherwise, all concentrations are given in weight percent and relate to the respective complete medium, all temperatures are given in degrees centigrade (Celsius) and all differences of temperatures in degrees centigrade. All physical properties have been and are determined according to Merck Liquid Crystals, Physical Properties of Liquid Crystals, Status November 1997, Merck KGaA, Germany and are given for a temperature of 20 C., unless explicitly stated otherwise.

(115) Throughout the description and claims of this specification, the words comprise and contain and variations of the words, for example comprising and comprises, mean including but not limited to, and are not intended to (and do not) exclude other components. On the other hand, the word comprise also encompasses the term consisting of but is not limited to it.

(116) It will be appreciated that variations to the foregoing embodiments of the invention can be made while still falling within the scope of the invention. Alternative features serving the same, equivalent, or similar purpose may replace each feature disclosed in this specification, unless stated otherwise. Thus, unless stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

(117) All of the features disclosed in this specification may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. In particular, the preferred features of the invention are applicable to all aspects of the invention and may be used in any combination.

(118) Likewise, features described in non-essential combinations may be used separately (not in combination).

(119) It will be appreciated that many of the features described above, particularly of the preferred embodiments, are inventive in their own right and not just as part of an embodiment of the present invention. Independent protection may be sought for these features in addition to or alternative to any invention presently claimed.

(120) The invention will now be described in more detail by reference to the following examples, which are illustrative only and do not limit the scope of the invention.

(121) Preferred features of the invention are summarized in form of a numbered list: 1. Birefringent RM lens obtainable from a polymerizable liquid crystalline medium consisting of a polymerizable liquid crystalline component (A) consisting of one or more polymerizable mesogenic compounds, and a non-polymerizable component (B), consisting of one or more non-polymerizable compounds. 2. Birefringent RM lens according to note 1, characterized in that the polymerizable liquid crystalline component (A) comprises at least one polymerizable mesogenic compound selected of formula I,
P-Sp-MG-R.sup.0I wherein P is a polymerizable group, Sp is a spacer group or a single bond, MG is a rod-shaped mesogenic group selected of formula M,
-(A.sup.21-Z.sup.21).sub.k-A.sup.22-(Z.sup.22-A.sup.23).sub.l-M A.sup.21 to A.sup.23 are in each occurrence independently of one another an aryl-, heteroaryl-, heterocyclic- or alicyclic group optionally being substituted by one or more identical or different groups L, Z.sup.21 and Z.sup.22 are in each occurrence independently from each other, O, S, CO, COO, OCO, SCO, COS, OCOO, CONR.sup.01, NR.sup.01CO, NR.sup.01CONR.sup.02, NR.sup.01COO, OCONR.sup.01, OCH.sub.2, CH.sub.2O, SCH.sub.2, CH.sub.2S, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, CF.sub.2CF.sub.2, CHN, NCH, NN, CHCR.sup.01, CY.sup.01CY.sup.02, CC, CHCHCOO, OCOCHCH, or a single bond, L is, in case of multiple occurrences independently of one another, H, halogen, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 5 C atoms, R.sup.0 is H, alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 20 C atoms or is Y.sup.0 or P-Sp-, Y.sup.0 is F, Cl, CN, NO.sub.2, OCH.sub.3, OCN, SCN, optionally fluorinated alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 4 C atoms, or mono- oligo- or polyfluorinated alkyl or alkoxy with 1 to 4 C atoms, Y.sup.01 and Y.sup.02 each, independently of one another, denote H, F, Cl or CN. R.sup.01 and R.sup.02 are independently of each other H, or straight chain or branched alkyl with 1 to 20 C-atoms, preferably 1 to 6 C-atoms, and k and l are each and independently 0, 1, 2, 3 or 4. 3. Birefringent RM lens according to note 1 or 2 characterized in that the polymerizable liquid crystalline component (A) comprises at least one polymerizable mesogenic compound selected formula II, and at least one polymerizable mesogenic compound selected of formula III,
P-Sp-(A.sup.21-Z.sup.21).sub.k-A.sup.22-(Z.sup.22-A.sup.23).sub.l-R.sup.0II
P-Sp-A.sup.31-Z.sup.31-A.sup.32-(Z.sup.32-A.sup.33).sub.l-R.sup.0III wherein P is a polymerizable group, Sp is a spacer group or a single bond, A.sup.21 to A.sup.33 are in each occurrence independently of one another an aryl-, heteroaryl-, heterocyclic- or alicyclic group optionally being substituted by one or more identical or different groups L, Z.sup.21 and Z.sup.22 are in each occurrence independently from each other, O, S, CO, COO, OCO, SCO, COS, OCOO, CONR.sup.01, NR.sup.01CO, NR.sup.01CONR.sup.02, NR.sup.01COO, OCONR.sup.01, OCH.sub.2, CH.sub.2O, SCH.sub.2, CH.sub.2S, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, CF.sub.2CF.sub.2, or a single bond, Z.sup.31 and Z.sup.32 are in each occurrence independently from each other CHN, NCH, NN, CHCR.sup.01, CY.sup.01CY.sup.02, CC, CHCHCOO, OCOCHCH, and if present both, one of Z.sup.31 and Z.sup.32 can also denote O, S, CO, COO, OCO, SCO, COS, OOCO, CONR.sup.01, NR.sup.01CO, NR.sup.01CONR.sup.02, NR.sup.01COO, OCONR.sup.01, OCH.sub.2, CH.sub.2O, SCH.sub.2, CH.sub.2S, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, L is, in case of multiple occurrences independently of one another, H, halogen, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 5 C atoms, R.sup.0 is H, optionally fluorinated alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 20 C atoms or is Y.sup.0 or P-Sp-, Y.sup.0 is F, Cl, CN, NO.sub.2, OCH.sub.3, OCN, SCN, optionally fluorinated alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 4 C atoms, or mono- oligo- or polyfluorinated alkyl or alkoxy with 1 to 4 C atoms, preferably F, Cl, CN, NO.sub.2, OCH.sub.3, or mono- oligo- or polyfluorinated alkyl or alkoxy with 1 to 4 C atoms, Y.sup.01 and Y.sup.02 each, independently of one another, denote H, F, Cl or CN. R.sup.01 and R.sup.02 are independently of each other H, or straight chain or branched alkyl with 1 to 20 C-atoms, preferably 1 to 6 C-atoms, and k and l are each and independently 0, 1, 2, 3 or 4. 4. Birefringent RM lens according to one or more of notes 1 to 3 characterized in that the polymerizable liquid crystalline component comprises A at least one polymerizable mesogenic compound selected of formulae II-1 to II-27, and at least one polymerizable mesogenic compound selected of formulae III-1 to III-12,

(122) ##STR00013## ##STR00014## ##STR00015## ##STR00016## ##STR00017## wherein P.sup.0 is, in case of multiple occurrences independently of one another, a polymerizable group, A.sup.0 is, in case of multiple occurrences independently of one another, 1,4-phenylene that is optionally substituted with 1, 2, 3 or 4 groups L, or trans-1,4-cyclohexylene, Z.sup.0 is, in case of multiple occurrences independently of one another, COO, OCO, CH.sub.2CH.sub.2, or a single bond, r is 0, 1, 2, 3 or 4, u and v are independently of each other 0, 1 or 2, w is 0 or 1, x and y are independently of each other 0 or identical or different integers from 1 to 12, z is 0 or 1, with z being 0 if the adjacent x or y is 0, the benzene and naphthalene rings can additionally be substituted with one or more identical or different groups L, and the parameter R.sup.0, Y.sup.0, R.sup.01, R.sup.02 and L have the same meanings as given above in formula I, and 5. Birefringent RM lens according to one or more of notes 1 to 4, characterized in that the polymerizable liquid crystalline component A comprises at least one polymerizable mesogenic compound selected of formulae IIa to IIc, and at least one polymerizable mesogenic compound selected of formulae IIIa to IIIh,

(123) ##STR00018## ##STR00019## wherein the parameter R.sup.0 has the same meaning as given above in formula I, x and y are independently of each other integers from 1 to 12. 6. Birefringent RM lens according to one or more of notes 1 to 5, characterized in that the non-polymerizable component (B) consists of at least one non-polymerizable compound selected from catalysts, sensitizers, stabilizers, polymerization initiators, inhibitors, chain-transfer agents, lubricating agents, wetting agents, dispersing agents, hydrophobing agents, adhesive agents, flow improvers, defoaming agents, deaerators, diluents, reactive diluents, auxiliaries, colourants or pigments. 7. Birefringent RM lens according to one or more of notes 1 to 6, characterized in that the amount of the polymerizable liquid-crystalline component A in the liquid crystalline medium is more than 95% by weight of the total liquid crystalline medium. 8. Birefringent RM lens according to one or more of notes 1 to 7, characterized in that the amount of the non-polymerizable component B in the liquid crystalline medium is less than 5% by weight of the total liquid crystalline medium. 9. Birefringent RM lens according to one or more of notes 1 to 8, characterized in that the birefringence (n) of the RM lens is in the range from 0.10 to 0.50. 10. Method of production of a birefringent RM lens according to one or more of notes 1 to 9, comprising the steps of providing a layer of a melt of the polymerizable liquid crystalline medium onto a substrate at room temperature or elevated temperature providing an inverse lens mould on top of the coated polymerizable liquid crystalline medium, annealing the polymerizable liquid crystalline medium in the mould at elevated temperature, cooling the mould, curing of the polymerizable liquid crystalline medium, and optionally removing the mould. 11. Use of a birefringent RM lens according to one or more of notes 1 to 9, in an electro optical device. 12. Electro optical device comprising at least one birefringent RM lens according to one or more of notes 1 to 9.

Examples

General Procedure

(124) Test cells, are prepared from polymerizable liquid-crystalline media summarized in table 2, comprising the given amounts of the compounds summarized in table 1, by melting the medium, flow filling the medium into a rubbed polyimide glass cell having a thickness of 20 m, annealing the medium at the given temperature for 3 min, cooling the medium to room temperature and curing the medium using UV light (250 nm-450 nm bandpass filter) at 50 mW/cm.sup.2 for 60 seconds (irradiation dose of 3000 mJ).

(125) The melting points, annealing temperatures and the physical characteristics, such as the resulting n and b-value for each example are summarized in table 3.

(126) TABLE-US-00001 TABLE 1 Compounds 0 (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) 0 (11) (12) (13) (14) (15) (16)

(127) TABLE-US-00002 TABLE 2 Compositions of examples 1 to 14 Compound* Example 1 Example 2 Example 3 Example 4 Example 5 (1) 19.73 19.73 19.73 19.73 19.73 (2) 15.78 15.78 15.78 15.78 15.78 (3) 23.68 23.68 23.68 23.68 23.68 (4) 11.84 11.84 11.84 11.84 11.84 (5) 7.89 7.89 7.89 7.89 7.89 (6) 20.00 (7) 20.00 (8) 20.00 (9) 20.00 (10) 20.00 (11) (12) (13) (14) (15) (16) Irganox 0.08 0.08 0.08 0.08 0.08 1076 Irgacure 1.00 1.00 1.00 1.00 1.00 651 Total 100.00 100.00 100.00 100.00 100.00 amount Example Compound* Example 6 Example 7 Example 8 Example 9 10 (1) 19.73 19.73 19.73 19.73 19.73 (2) 15.78 15.78 15.78 15.78 15.78 (3) 23.68 23.68 23.68 23.68 23.68 (4) 11.84 11.84 11.84 11.84 11.84 (5) 7.89 7.89 7.89 7.89 7.89 (6) (7) (8) (9) (10) (11) 20.00 (12) 20.00 (13) 20.00 (14) 20.00 (15) 20.00 (16) Irganox 0.08 0.08 0.08 0.08 0.08 1076 Irgacure 1.00 1.00 1.00 1.00 1.00 651 Total amount 100.00 100.00 100.00 100.00 100.00 Compound* Example 11 Example 12 Example 13 Example 14 (1) 19.73 32.00 7.00 24.73 (2) 15.78 14.92 7.00 19.78 (3) 23.68 8.00 29.92 29.68 (4) 11.84 4.00 10.00 14.84 (5) 7.89 5.00 9.89 (6) (7) (8) 40.00 40.00 (9) (10 (11) (12) (13) (14) (15) (16) 20.00 Irganox 0.08 0.08 0.08 0.08 1076 Irgacure 1.00 1.00 1.00 1.00 651 Total 100.00 100.00 100.00 100.00 amount Example Compound* Example 15 Example 16 Example 17 18 (1) 21.73 18.73 15.78 12.73 (2) 17.38 14.98 12.57 10.18 (3) 26.08 22.48 18.86 15.28 (4) 13.04 11.24 9.43 7.64 (5) 8.69 7.49 6.28 5.09 (6) (7) 12.00 24.00 36.00 48.00 (8) (9) (10) (11) (12) (13) (14) (15) (16) Irganox 0.08 0.08 0.08 0.08 1076 Irgacure 1.00 1.00 1.00 1.00 651 Total amount 100.00 100.00 100.00 100.00 *all given amounts in % w/w

(128) TABLE-US-00003 TABLE 3 Physical characteristics and annealing temperatures of examples 1 to 14 Annealing Transmission Mp. temp. at 550 nm Example n [ C.] [ C.] b-value [%] 1) 0.235 89.0 86.0 10.0 95.4 2) 0.220 106.7 104.0 6.4 96.1 3) 0.219 97.7 95.0 5.4 95.4 4) 0.210 76.7 74.0 5.7 97.1 5) 0.214 92.8 90.0 5.0 96.6 6) 0.226 100.3 97.0 6.8 93.4 7) 0.165 86.8 84.0 6.6 95.5 8) 0.185 83.8 81.0 5.0 96.9 9) 0.193 89.6 87.0 5.0 96.1 10) 0.189 106.0 103.0 4.7 96.5 11) 0.185 88.6 86.0 5.3 94.9 12) 0.240 90.1 80.0 6.6 13) 0.240 122.1 112.0 6.5 14) 0.157 91.2 89.0 5.1 97.6 15) 0.212 97.7 80.0 8.8 96.9 16) 0.254 109.0 80.0 9.5 95.4 17) 0.294 124.9 80.0 9.8 96.0 18) 0.338 137.5 80.0 10.2 93.4

(129) As can be seen from table 3, all examples show high values for the birefringence, low values for the yellowness index and high values for the transmission. Moreover, all examples showed an homogeneous planar alignment, which was confirmed by dark state testing between crossed polarizers.