Liquid crystal device

1 . A liquid crystal device comprising at least two opposing transparent substrates, at least one liquid crystal switching layer sandwiched between said at least two opposing substrates comprising:

a polymer obtainable from one or more photoreactive mesogens of formula I,

R 11 -Sp 11 -X 11 [-A-Z] o -A 11 -CY 11 ═CY 12 [—C═O] x [—O] y -A[-Z-A] p -X 21 -Sp 21 -R 21   I

wherein

A 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 are each optionally replaced by N and wherein, in addition, one or more H atoms are each optionally replaced by L,

b) a group selected from the group consisting of

where, in addition, one or more H atoms in these radicals are optionally replaced by L, and/or one or more double bonds are optionally replaced by single bonds, and/or one or more CH groups are optionally replaced by N,

A have each, independently of one another, in each occurrence one of the meanings for A 11 or

a) group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, wherein, in addition, one or more non-adjacent CH 2 groups are each optionally replaced by —O— or —S— and wherein, in addition, one or more H atoms are optionally 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 2 , SF 5 , —NCO, —NCS, —OCN, —SCN, —C(═O)N(R z ) 2 , —C(═O)R z , —N(R z ) 2 , optionally substituted silyl, optionally substituted aryl having 6 to 20 C atoms, or straight-chain alkyl or alkoxy having 1 to 25 C atoms, straight chain alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy, alkoxycarbonyloxy having 2 to 25 C atoms, branched or cyclic alkyl or alkoxy having 3 to 25 C atoms, or branched or cyclic alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy, or alkoxycarbonyloxy having 4 to 25 C atoms, or X 21 —Sp 21 -R 21 ,

M denotes —O—, —S—, —CH 2 —, —CHR z — or —CR y R z —,

R y and R z each, independently of one another, denote H, CN, F, or alkyl having 1-12 C atoms, wherein one or more H atoms are each optionally replaced by F,

Y 11 and Y 12 each, independently of one another, denote H, F, phenyl, or optionally fluorinated alkyl having 1-12 C atoms,

Z denotes, independently of each other, in each occurrence, a single bond, —COO—, —OCO—, —O—CO—O—, —OCH 2 —, -CH 2 O—, —OCF 2 -, -CF 2 O—, (CH 2 ) n —, —CF 2 CF 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,

o and p denote each and independently 0, 1 or 2,

x and y denote each and independently 0 or 1, under the condition that if x denotes 0, y cannot denote 1,

X 11 and X 21 denote independently from one another, in each occurrence a single bond, —CO—O—, —O—CO—, —O—COO—, —O—, —CH═CH—, —C≡C—, —CF 2 —O—, —O—CF 2 —, —CF 2 —CF 2 —, —CH 2 —O—, —O—CH 2 —, —CO—S—, —S—CO—, —CS—S—, —S—CS—, —S—CSS—, or —S—,

Sp 11 and Sp 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 2 groups are each optionally replaced by —O—, —S—, —NH—, —N(CH 3 )—, —CO—, —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O—, —CF 2 —, —CF 2 O—, —OCF 2 — —CH(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 11 denotes P,

R 21 denotes P, halogen, CN, optionally fluorinated alkyl, or alkenyl with up to 15 C atoms in which one or more non-adjacent CH 2 -groups are each optionally replaced by

—O—, —S—, —CO—, -C(O)O—, —O—C(O)-, O—C(O)—O—,

P each and independently from another in each occurrence a polymerizable group,

and one or more nematogenic compounds;

wherein an electrode structure is provided on one or both of the at least two opposing substrates, wherein one or more of said at least two opposing substrates correspond to an optical grating or a lens structure, or one or more of said at least two opposing substrates are additionally provided with an optical grating or a lens structure adjacent to the at least one liquid crystal switching layer; and

wherein said device is a beam focusing device.

2 . The device according to claim 1 , wherein said one or more of said at least two opposing substrates correspond to or are provided with:

a plano-concave lens structure,

a plano-convex lens structure,

a bi-convex lens structure,

a bi-concave lens structure,

a refractive Fresnel lens structure, or

a diffractive Fresnel lens structure.

3 . The device according to claim 1 , wherein one or more of said at least two opposing substrates correspond to or are provided with:

a surface relief grating,

a blazed grating,

a volume grating,

a Pancharatnam-Berry grating, or

a Bragg Polarization Grating.

4 . The device according to claim 1 , wherein the at least one liquid crystal switching layer has a maximum thickness in the range from 1 μm to 100 μm.

5 . The device according to claim 1 , wherein the electrode structure is selected from interdigitated electrodes, IPS electrodes, FFS electrodes, and comb like electrodes.

6 . The device according to claim 1 , wherein said one or more nematogenic compounds are selected from the following formulae:

wherein

a is 1 or 2,

b is 0 or 1,

 denotes

R 1 and R 2 each, independently of one another, denote alkyl having 1 to 12 C atoms, where, in addition, one or more non-adjacent CH 2 groups are each optionally 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 x denotes —CH═CH—, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —O—, —CH 2 —, —CH 2 CH 2 —, or a single bond, and

L 1-4 each, independently of one another, denote F, Cl, OCF 3 , CF 3 , CH 3 , CH 2 F, or CHF 2 .

7 . The device according to claim 1 , wherein said one or more nematogenic compounds are selected from the following formula:

in which the individual radicals have the following meanings:

 denotes

 denotes

R 3 and R 4 each, independently of one another, denote alkyl having 1 to 12 C atoms, in which, in addition, one or two non-adjacent CH 2 groups are each optionally 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, and

Z y denotes —CH 2 CH 2 —, —CH—CH—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —CO—O—, —O—CO—, -C 2 F 4 -, —CF=CF—, —CH═CH—CH 2 O—, or a single bond.

8 . A method of production of a device according to claim 1 , comprising one or more of the following steps:

providing an electrode structure on one or more of said at least two opposing substrates, providing an optical grating or a lens structure on one or more substrates, and assembling a cell from said at least two opposing substrates,

filling the cell with a liquid crystal medium comprising one or more photoreactive-mesogens of formula I and one or more nematogenic compounds,

irradiating the cell with linearly polarized light,

curing the polymerizable compounds of the liquid crystal medium by irradiation with ultraviolet light or visible light having a wavelength of 450 nm or below whereby the liquid crystal medium forms said at least one switching layer.

9 . An electro-optical device comprising the liquid crystal device according to claim 1 .

10 . The electro-optical device according to claim 9 , wherein the electro-optical device is a device for augmented reality applications or a device for virtual reality applications.

11 . The electro-optical device according to claim 9 , wherein the electro-optical device is goggles or contact lens.

12 . The device according to claim 1 , wherein that at least one liquid crystal switching layer contains from 0.01 to 10 weight % of mesogens of formula I.

13 . The device according to claim 1 , wherein that at least one liquid crystal switching layer contains from 0.05 to 5 weight % of mesogens of formula I.

14 . The device according to claim 1 , wherein that at least one liquid crystal switching layer contains from 0.1 to 3 weight % of mesogens of formula I.

15 . The device according to claim 1 , wherein the mesogens of formula I are selected from compounds RM-1 to RM-3:

16 . The device according to claim 1 , wherein said one or more nematogenic compounds are selected from the following formulae:

wherein

R 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 2 groups in these radicals are each optionally replaced, independently of one another, by-C≡C—, —CF 2 O—, —CH═CH—,

 O—, —CO—O—, or —O—CO— in such a way that O atoms are not linked directly to one another,

X 20 each, identically or differently, denote F, CI, CN, SF 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,

Y 20-24 each, identically or differently, denote H or F,

W denotes H or methyl, and

 each, identically or differently, denote

17 . The device according to claim 1 , wherein said one or more nematogenic compounds are selected from the following formulae:

wherein

R 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 2 groups in these radicals are each optionally replaced, independently of one another, by-C≡C—, CF 2 O—, —CH═CH—,

 —O—, —CO—O—, or —O—CO— in such a way that O atoms are not linked directly to one another,

X 20 each, identically or differently, denote F, CI, CN, SF 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,

Y 20 -24 each, identically or differently, denote H or F,

W denotes H or methyl,

 each, independently of one another, denote

and

 denotes