Liquid crystal medium

Abstract

The present invention relates to liquid crystal (LC) media or LC materials, and to energy efficient liquid crystal displays (LCDs) containing these media, in particular to game displays and AR / VR headsets addressed by active matrices, in particular to LC displays of the TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, XB-FFS, PS-FFS, SA-HB-FFS, SA-XB-FFS, polymer stabilized SA-HB-FFS, polymer stabilized SA-XB-FFS, positive VA or positive PS-VA type.

Description

Technical Field

[0001] The present invention relates to liquid crystal (LC) media, and to energy-saving liquid crystal displays (LCDs) containing these media, in particular to high-contrast gaming displays and AR / VR headsets addressed by an active matrix, in particular to LC displays of the TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, XB-FFS, PS-FFS, SA-HB-FFS, SA-XB-FFS, polymer-stabilized SA-HB-FFS, polymer-stabilized SA-XB-FFS, positive VA or positive PS-VA type. In a preferred embodiment, the LC medium has a positive dielectric anisotropy. Background Art

[0002] Liquid crystal displays (LCDs) are used in many fields for information display. LCDs are used for both direct view and projection displays. The electro-optical modes used are, for example, twisted nematic (TN), super twisted nematic (STN), optically compensated bend (OCB) and electrically controlled birefringence (ECB) modes and their various variations, as well as other modes. All of these modes utilize an electric field generated substantially perpendicular to the substrate and the LC layer.

[0003] In addition to these modes, there are also electro-optical modes which exploit an electric field substantially parallel to the substrate or LC layer. For example, WO 91 / 10936 discloses an LC display in which the electric signal is generated in such a way that the electric field has a significant component parallel to the LC layer, which has since been referred to as an "in-plane switching" (IPS) display. The operating principle of such a display is described, for example, by RA Soref in Journal of Applied Physics, Vol. 45, No. 12, pp. 5466-5468 (1974).

[0004] IPS displays contain an LC layer between two substrates with a planar orientation, wherein the two electrodes are arranged on only one of the two substrates and preferably have an interdigitated comb structure. When a voltage is applied to the electrodes, an electric field with a significant component parallel to the LC layer is generated between the electrodes. This leads to a realignment of the LC molecules in the layer plane.

[0005] For example, EP 0 588 568 discloses various possibilities for electrode design and addressing of IPS displays. DE 198 24 137 likewise describes various embodiments of such IPS displays.

[0006] Liquid-crystal materials for IPS displays of this type are described in DE 195 28 104, for example.

[0007] Furthermore, so-called "fringe field switching" (FFS) displays have been reported (see in particular SH Jung et al., Jpn. J. Appl. Phys. [Japanese Journal of Applied Physics], Vol. 43, No. 3, 2004, 1028), which contain two electrodes on the same substrate, one of which is structured in a comb-like manner and the other is unstructured. This results in strong so-called "fringe fields", i.e. strong electric fields close to the edges of the electrodes and, in the entire liquid crystal cell, electric fields with both strong vertical and strong horizontal components. FFS displays have a low viewing angle dependence of the contrast. FFS displays usually contain an LC medium with positive dielectric anisotropy and an alignment layer, usually consisting of polyimide, which provides a planar alignment for the molecules of the LC medium.

[0008] Liquid crystal displays in the IPS and FFS electro-optical modes are particularly suitable for modern desktop monitors, television sets and multimedia applications. The LC media according to the invention are preferably used for displays of this type. Usually, dielectrically positive LC media with rather low dielectric anisotropy values ​​are used for FFS displays, but in some cases LC media with dielectric anisotropy values ​​of only about 3 or even lower are also used in IPS displays.

[0009] Further improvements have been achieved through the HB-FFS mode. One of the unique features of the HB-FFS mode compared to conventional FFS technology is its ability to achieve higher transmittance, which allows the panel to operate with lower power consumption.

[0010] Another mode that has been developed recently is the XB-FFS mode, in which the LC medium additionally contains polar liquid crystal compounds with low dielectric anisotropy.

[0011] Liquid crystal compositions suitable for LCDs, in particular for FFS and IPS displays, are known in the prior art, for example from JP 07-181 439 (A), EP 0 667 555, EP 0 673 986, DE 195 09 410, DE 195 28 106 and DE 195 28 107. However, these compositions have certain disadvantages. Among other drawbacks, they mostly lead to disadvantageously long addressing times, have insufficient resistivity values ​​and / or require too high an operating voltage. Not only the operating characteristics but also the shelf life must be improved.

[0012] FFS and IPS displays can be operated as active matrix displays (AMD) or passive matrix displays (PMD). In the case of active matrix displays, the individual pixels are usually addressed by integrated non-linear active elements such as thin film transistors (TFTs), while in the case of passive matrix displays, the individual pixels are usually addressed by multiplexing methods as known in the art.

[0013] The displays according to the invention are preferably addressed by an active matrix, preferably by a matrix of TFTs. However, the LC media according to the invention can also be advantageously used in displays having other known addressing mechanisms.

[0014] Typical applications of IPS and FFS technologies are monitors, laptops, TVs, mobile phones, tablets, etc. Both IPS and FFS technologies have certain advantages over other LCD technologies, such as vertical alignment (VA) technology, such as wide viewing angle dependency of contrast.

[0015] The provision of further LC media and their use in displays with high transmittance, a good black state and a high contrast ratio is a core challenge for modern FFS and IPS applications. Furthermore, modern applications also require good low temperature stability and fast addressing times.

[0016] It has not been possible to design materials with high contrast, such as high elastic constants K1 and K av Suitable LC media with low switching speeds, low temperature stability and low response times are still needed. Therefore, the overall image quality in such devices still needs further improvement. In particular, in the field of gaming applications, other parameters related to image quality are often sacrificed in order to achieve fast switching speeds. Summary of the invention

[0017] The object of the present invention is to provide LC media, in particular for energy-saving gaming FFS and IPS displays and AR / VR headsets, but also for TN, positive VA or STN displays, in particular for active-matrix displays, such as those addressed by TFTs, which combine a high average elastic constant K av With low response time parameter (γ1 / K1) and low rotational viscosity and relatively low birefringence △n. In addition, they need to have high specific resistance, low threshold voltage, high dielectric anisotropy, good low temperature stability (LTS), fast response time and be able to achieve high brightness. In the case of FFS displays, response time, contrast, brightness and reliability need to be further optimized. However, it is found that the LC materials of the prior art often do not achieve all these requirements at the same time.

[0018] Unexpectedly, the above technical problem has been solved by providing an LC medium as described and claimed hereinafter.

[0019] EP 3 839 009 A1 describes LC media comprising one or more compounds of the formula T:

[0020]

[0021] and one or more compounds of formula L

[0022]

[0023] The examples of EP 3 839 009 A1 teach inter alia LC media comprising a combination of a compound of the formula T and a compound of the formula L.

[0024] It has now been found that, unexpectedly, the LC media according to the invention exhibit several significant improvements, especially when used in displays in the FFS mode, such as a high average elastic constant K av , low response time parameter (γ1 / K1), together with low rotational viscosity and good solubility, and can achieve a fast response time, the medium contains a combination of the following compounds: one or more compounds of formula G

[0025]

[0026] one or more compounds of formula LP1,

[0027]

[0028] and, optional

[0029] One or more compounds of formula LP2

[0030]

[0031] The individual substituents are clearly stated in claim 1.

[0032] Furthermore, the LC media according to the invention have high definition bright spots, excellent low temperature stability (LTS) and offer optimum dynamic image quality and improved overall image quality, in particular a high contrast ratio.

[0033] The present invention relates to an LC medium, characterised in that it comprises one or more compounds of the formula G

[0034]

[0035] The substituents have the following meanings:

[0036] R 1 and R 2 Each independently represents an H atom, a halogen atom, -CN, -SCN, -NCS, an alkyl or alkoxy group having 1 to 12 C atoms, or an alkenyl or alkenyloxy group having 2 to 12 C atoms, wherein one or more non-adjacent CH2 groups are optionally replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- is substituted in such a way that the O atoms are not directly attached to one another and in which one or more H atoms may be replaced by halogen atoms or a cycloalkyl or cycloalkoxy radical having 3 to 12 C atoms in which one or more H atoms may be replaced by halogen atoms;

[0037] Y 1 represents an H atom, an alkyl group having 1 to 3 C atoms or an alkenyl group having 2 to 3 C atoms, wherein one or more non-adjacent CH2 groups are optionally substituted by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- in such a way that the O atoms are not directly connected to one another;

[0038] A 1 and A 2 each independently of one another represents phenylene-1,4-diyl, wherein, in addition, one or two CH groups may be replaced by N and one or more H atoms may be replaced by halogen, CN, CH3, CHF2, CH2F, CF3, OCH3, OCHF2 or OCF3; cyclohexane-1,4-diyl, wherein, in addition, one or two non-adjacent CH2 groups may be replaced independently of one another by O and / or S and one or more H atoms may be replaced by F; cyclohexene-1,4-diyl, bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, tetrahydropyran-2,5-diyl or 1,3-dioxane-2,5-diyl;

[0039] Z 1 and Z 2 Each independently represents -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CO-O-, -O-CO-, -C2H4-, -C2F4-, -CF2CH2-, -CH2CF2-, -CFHCFH-, -CFHCH2-, -CH2CFH-, -CF2CFH-, -CFHCF2-, -CH=CH-, -CF=CH-, -CH=CF-, -CF=CF-, -C≡C- or a single bond;

[0040] k and l each independently represent 0, 1, 2 or 3;

[0041] one or more compounds of formula LP1,

[0042]

[0043] and optional

[0044] One or more compounds of formula LP2

[0045]

[0046] The substituents have the following meanings:

[0047] R 0 and R 3 Alkyl or alkoxy having 1 to 12 C atoms or alkenyl or alkenyloxy having 2 to 12 C atoms, wherein one or more non-adjacent CH2 groups are optionally replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- is substituted in such a way that the O atoms are not directly attached to one another and wherein one or more H atoms may be replaced by a cycloalkyl or cycloalkoxy group having 3 to 12 C atoms;

[0048] L 1 and L 2 Each independently represents H, F or Cl;

[0049] Y 0 With the Y in the pair G 1 One of the meanings given;

[0050] X 0 represents an F atom, CN, SCN, NCS or an alkyl or alkoxy group having 1 to 6 C atoms or an alkenyl or alkenyloxy group having 2 to 6 C atoms, wherein one or more H atoms are replaced by F atoms.

[0051] The LC media according to the invention are particularly suitable for gaming energy-saving LC displays and AR / VR headsets in FFS, HB-FFS, XB-FFS and IPS modes based on dielectrically positive liquid crystals, and polymer-stabilized variants thereof.

[0052] The invention further relates to the use of an LC medium as described above and below for electro-optical purposes, in particular for LC displays, shutter glasses, LC windows, 3D applications, preferably in TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, XB-FFS, PS-HB-FFS, PS-XB-FFS, SA-HB-FFS, SA-XB-FFS, polymer-stabilized SA-HB-FFS, polymer-stabilized SA-XB-FFS, positive VA and positive PS-VA displays, very preferably in FFS, HB-FFS, IPS, PS-HB-FFS and PS-IPS displays.

[0053] The invention further relates to an electro-optical LC display comprising an LC medium as described above and below, in particular a TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, XB-FFS, PS-HB-FFS, PS-XB-FFS, SA-HB-FFS, SA-XB-FFS, polymer-stabilized SA-HB-FFS, polymer-stabilized SA-XB-FFS, positive VA or positive PS-VA display, preferably a FFS, HB-FFS, IPS, PS-HB-FFS or PS-IPS display.

[0054] In the present application, all atoms also include their isotopes. In some embodiments, one or more hydrogen atoms (H) may be optionally replaced by deuterium (D); high deuteration enables or simplifies analytical determination of compounds, especially at low concentrations.

[0055] In formulas G, LP1, and LP2, if R 1 , R 2 , R 3 , R 0 , Y 0 and Y 1 R represents an alkyl group and / or an alkoxy group, which may be straight-chain or branched. It is preferably straight-chain, has 2, 3, 4, 5 or 6 C atoms, and preferably represents ethyl, propyl, butyl, pentyl, hexyl, ethoxy, propoxy, butoxy, pentyloxy or hexyloxy, and also represents methyl, methoxy. R preferably represents a straight-chain alkyl group having 1 to 6 C atoms or an alkenyl group having 2 to 6 C atoms.

[0056] Oxaalkyl preferably represents straight-chain 2-oxapropyl (=methoxymethyl), 2-oxabutyl (=ethoxymethyl) or 3-oxabutyl (=2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl.

[0057] If R 1 , R 2 , R 3 , R 0 , Y 0 and Y 1 represents an alkoxy group or an oxaalkyl group which may also contain one or more additional oxygen atoms, provided that the oxygen atoms are not directly bonded to each other.

[0058] In another preferred embodiment, R 1 , R 2 , R 3 or R 0 One or more selected from -S1 -F, -OS 1 -F, -O-S1-O-S2, where S 1 It is C 1-12 -alkylene or C 2-12 -alkenylene, and S 2 It is H, C 1-12 -alkyl or C 2-12 -alkenyl, very preferably, R 1 , R 2 , R 3 or R 0 One or more selected from -OCH2OCH3, -O(CH2)2OCH3, -O(CH2)3OCH3, -O(CH2)4OCH3, -O(CH2)2F, -O(CH2)3F, -O(CH2)4F.

[0059] If R 1 , R 2 , R 3 , R 0 , Y 0 and Y 1 alkylene radical, wherein the alkylene radical is a ...

[0060] If R 1 , R 2 , R 3 , R 0 , Y 0 and Y 1 If alkyl or alkenyl is at least monosubstituted by halogen, the radical is preferably straight-chain and halogen is preferably F or Cl. In the case of polysubstitution, halogen is preferably F. The resulting radicals also include perfluorinated radicals. In the case of monosubstitution, the fluorine or chlorine substituent can be in any desired position, but is preferably in the ω-position.

[0061] Particularly preferred groups Y in formula G are 1 and Y in LP1 and LP20 represents an H atom, an alkyl group having up to 3 atoms or an alkenyl group. Very particularly preferably, Y 0 and Y 1 represents a methyl group or a H atom, with a H atom being most preferred.

[0062] A in formula G 1 and A 2 Particularly preferably it represents phenylene-1,4-diyl, which may also be mono- or polysubstituted by F, and also cyclohexane-1,4-diyl, cyclohexenylene-1,4-diyl, tetrahydropyran-2,5-diyl or 1,3-dioxane-2,5-diyl.

[0063] A in formula G 1 and A 2 Particularly preferred

[0064]

[0065] Unsubstituted 1,4-phenylene is preferred, wherein L 1 and L 2 represents halogen, CF3 or CN, preferably F.

[0066] Z in formula G 1 and Z 2 Particularly preferably it represents -CF2O-, -OCF2- or a single bond, among which a single bond is most preferred.

[0067] Also preferred are compounds of formula G, wherein R 1 and R 2 each independently of one another represents H, F, Cl, Br, -CN, -SCN, -NCS or alkyl, alkenyl or alkynyl having up to 8, preferably up to 5, C atoms, each of which is optionally substituted by halogen, in particular by F.

[0068] Particularly preferred radicals R in the formulae G, LP1 and LP2 are 1 , R 2 , R 3 and R 0 represents H, halogen or alkyl, alkenyl, alkynyl or alkoxy having up to 12, preferably up to 8, C atoms, each of which is optionally substituted by halogen, in particular by F, particularly preferably H, F, alkyl, alkenyl or alkynyl having up to 8 C atoms. Preferably, the radical R 1 and R 2 At least one of, or R 3 and R 0 At least one of the groups R in formula G is not H. 1 , R 2 , or the group R in formula LP1 3 and R0 None of them represent H atoms. 1 and R 3 Very particularly preferably, R 1 and R 3 is an alkyl group. 1 , R 2 , R 3 and R 0 each independently of one another very particularly preferably represents a straight-chain alkyl radical having 1 to 5 C atoms. 1 , R 2 , R 3 and R 0 represents a substituted alkyl, alkoxy, alkenyl or alkynyl group, then the two groups R 1 and R 2 , or R 3 and R 0 The total number of C atoms in each case is preferably less than 10.

[0069] Preferred alkyl groups are, for example, methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl and n-octyl.

[0070] Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl and pentenyl.

[0071] Preferred alkynyl groups are, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl and octynyl.

[0072] Preferred alkoxy groups are, for example, methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, n-hexoxy, n-heptyloxy, n-octyloxy.

[0073] The halogen atom preferably represents F or Cl, F being most preferred.

[0074] Particularly preferred compounds of formula G are those selected from the following sub-formulae:

[0075]

[0076]

[0077] Where R 1 , R 2 and Y 1 has the meanings indicated in the general formula G. In a particularly preferred embodiment, the compound of formula G is selected from structure G-1.

[0078] LC media according to the invention having particularly high LTS, a broad nematic phase range and also high long-term stability to UV radiation and elevated temperature and low rotational viscosity are obtainable with the following compounds of the general formula G:

[0079]

[0080]

[0081] wherein n and m each independently represent 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12.

[0082] The most preferred compounds of formula G include in particular one or more of the following compounds:

[0083]

[0084]

[0085] In a further preferred embodiment, the compound of the following formula G may be used:

[0086]

[0087]

[0088]

[0089] The compounds of the formula G can be prepared analogously to methods known to the person skilled in the art and described in standard works of organic chemistry, for example Houben-Weyl, Methoden der organischen Chemie [Methods in Organic Chemistry], Thieme Verlag, Stuttgart.

[0090] The proportion ωG of compounds of the formula G or preferably their subformula G-1-1 in the LC medium is preferably from 0.5 to 20% by weight, very preferably from 1 to 15% by weight and most preferably from 2 to 10% by weight.

[0091] The one or more compounds of formula LP1 and LP2 may preferably be described by the following formulae LP1-1 and LP2-1:

[0092]

[0093]

[0094] in

[0095] R 0 is an alkyl or alkoxy radical having 1 to 6 C atoms or an alkenyl radical having 2 to 6 C atoms, wherein one or more CH2 radicals are optionally replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- is substituted in such a way that the O atoms are not directly attached to each other and one or more H atoms may be replaced by a halogen atom;

[0096] R 3 is an alkyl radical having 1 to 6 C atoms, wherein one or more CH2 groups are optionally replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- is substituted in such a way that the O atoms are not directly attached to each other and one or more H atoms may be replaced by a halogen atom;

[0097] X 0 is an F atom or an alkyl or alkoxy group having 1 to 3 C atoms or an alkenyl or alkenyloxy group having 2 or 3 C atoms, wherein one or more H atoms are replaced by an F atom; and

[0098] Y 0 It is H or CH3.

[0099] The compounds of the general formula LP1 and LP2 can also be represented by one of the following formulae:

[0100]

[0101]

[0102] in

[0103] R 0 is an alkyl or alkoxy group having 1 to 12 C atoms, wherein one or more CH2 groups are optionally replaced by -C≡C-, -CF2O-, -OCF2-, -O-, -CO-O- or -O-CO-substituted in such a way that the O atoms are not directly attached to one another and in which one or more H atoms may be replaced by halogen atoms, preferably alkyl having 1 to 4 C atoms, alkenyl or alkenyloxy having 2 to 6 C atoms or cycloalkyl or cycloalkoxy having 3 to 6 C atoms, with vinyl, allyl or cyclopentyl being particularly preferred;

[0104] n represents 1, 2, 3, 4 or 5; and

[0105] m represents 1, 2, 3 or 4.

[0106] Particularly preferred compounds of formula LP1 are those selected from the following sub-formulae:

[0107]

[0108]

[0109] where Y 0 It is H or CH3, preferably H.

[0110] Very preferred are compounds of formula LP1-1a, LP1-1b and LP1-1c, most preferred are compounds of formula LP1-1a.

[0111] Particularly preferred compounds of formula LP2 are those selected from the following sub-formulae:

[0112]

[0113]

[0114]

[0115] where Y 0 It is H or CH3, preferably H.

[0116] Very preferred are compounds of formula LP2-1a, LP2-1b, LP2-1c, LP2-1d and LP2-1i, LP2-2b, LP2-3a, LP2-3c, and most preferred is the compound of formula LP2-1b.

[0117] Preferably, the LC medium comprises one compound of formula LP1 and one compound of formula LP2.

[0118] The total proportion of compounds of the formula LP1 or its subformulae in the LC medium is preferably 2 to 35% by weight, very preferably 3 to 25% by weight, most preferably 4 to 15% by weight. The total proportion of compounds of the formula LP2 or its subformulae in the LC medium is preferably 2 to 35% by weight, very preferably 3 to 25% by weight, most preferably 4 to 15% by weight.

[0119] Additional components

[0120] In a preferred embodiment, the LC medium may further comprise one or more compounds selected from the following formulae II and III:

[0121]

[0122] The substituents have the following meanings independently of one another and identically or differently on each occurrence:

[0123]

[0124]

[0125] R 0 Represents R in formula G 1 and R 2 One of the meanings given;

[0126] X 0 independently of one another represent F, Cl, haloalkyl, haloalkenyl, haloalkoxy or haloalkenyloxy having up to 6 C atoms;

[0127] L 1-6 independently represent H or F; and

[0128] Y 0 It represents H or CH3.

[0129] Preferred compounds of formula II and III are those wherein Y 0 Those for H.

[0130] Further preferred compounds of formula II and III are those wherein R 0 represents an alkyl radical having 1 to 6 C atoms, very preferably an ethyl radical or a propyl radical, and X 0 represents F or OCF3, those of F being very preferred.

[0131] In a preferred embodiment, the LC medium comprises one or more compounds of formula II selected from the following subformulae:

[0132]

[0133] Where R 0 and X 0 has the meaning given in formula II.

[0134] Preferred compounds are those of the formulae II-1, II-2 and II-3, very preferred are those of the formulae II-1 and II-2.

[0135] In the compounds of formulae II-1 to II-7, R 0 preferably represents alkyl having 1 to 6 C atoms, very preferably ethyl or propyl, and X 0 Preferably it represents F or OCF3, very preferably F.

[0136] In one embodiment, the LC medium contains one or more compounds of formula II or subformulae thereof as described above and below, wherein Y 0 According to this preferred embodiment, the LC medium may comprise one or more compounds of formula II selected from the following subformulae:

[0137]

[0138]

[0139] Where R 0 and X 0 has the meaning given in formula II.

[0140] Preferred compounds are those of formulae IIA-1, IIA-2 and IIA-3, very preferred are those of formulae IIA-1 and IIA-2.

[0141] In the compounds of Formulae IIA-1 to IIA-7, R 0 preferably represents alkyl having 1 to 6 C atoms, very preferably ethyl or propyl, and X 0 Preferably it represents F or OCF3, very preferably F.

[0142] The proportion of the compound of the formula II in the LC medium is generally from 0 to 20% by weight, very preferably from 1 to 15% by weight and most preferably from 2 to 10% by weight.

[0143] In a further preferred embodiment, the LC medium comprises one or more compounds of the formula III selected from the following subformulae:

[0144]

[0145]

[0146]

[0147]

[0148] Where R 0 and X 0 has the meaning given in formula II.

[0149] Preferred compounds are those of formula III-1, III-4, III-6, III-16, III-19 and III-20.

[0150] In the compounds of formulae III-1 to III-21, R 0 Preferably denotes alkyl having 1 to 6 C atoms, very preferably ethyl or propyl, X 0 Preferably represents F or OCF3, very preferably F, and Y 0 Preferably it represents H.

[0151] The LC medium may contain one or more compounds of the formula III or its subformulae as described above and below, wherein Y 0 The medium according to this preferred embodiment may contain one or more compounds of formula III selected from the following subformulae:

[0152]

[0153]

[0154]

[0155]

[0156] Where R 0 and X 0 has the meaning given in formula III.

[0157] Preferred compounds are those of Formula IIIA-1, IIIA-4, IIIA-6, IIIA-16, IIIA-19 and IIIA-20.

[0158] In the compounds of formula IIIA-1 to IIIA-21, R 0 Preferably denotes alkyl having 1 to 6 C atoms, very preferably ethyl or propyl, X 0 Preferably represents F or OCF3, very preferably F, and Y 2 Preferably it represents F.

[0159] The proportion of the compound of the formula III in the LC medium is preferably from 5 to 60% by weight, very preferably from 10 to 50% by weight and most preferably from 20 to 40% by weight.

[0160] In a further preferred embodiment, the LC medium may additionally comprise one or more compounds selected from the following formulae:

[0161]

[0162]

[0163] in

[0164] R 0 , X 0 , L 1-4 and Y 0 has the meanings shown in formula II and III,

[0165] Z 0 represents -C2H4-, -(CH2)4-, -CH=CH-, -CF=CF-, -C2F4-, -CH2CF2-, -CF2CH2-, -CH2O-, -OCH2-, -COO-, -CF2O- or -OCF2-, and in formulas V and VI also represents a single bond; and

[0166] s represents 0 or 1.

[0167] The compound of formula IV is preferably selected from the following formulae:

[0168]

[0169]

[0170] Where R 0 and X 0 have the meanings indicated in formulae II and III.

[0171] R 0 Preferably, X represents an alkyl radical having 1 to 6 C atoms. 0 Preferably it represents F or OCF3, and alternatively it represents OCF=CF2 or Cl.

[0172] The compound of formula IVa is preferably represented by the following sub-formula:

[0173]

[0174] The compound of formula IVb is preferably represented by the following formula:

[0175]

[0176] The compound of formula IVc is preferably represented by the following sub-formula:

[0177]

[0178] Where R 0 has the meanings indicated in formula II and is preferably propyl or pentyl.

[0179] The compounds of the formula IVc, in particular of the formula IVc-1, are preferably used in the LC media according to the invention in an amount of from 1 to 20% by weight, particularly preferably from 2 to 15% by weight.

[0180] The compounds of formula V are preferably selected from the following sub-formulae:

[0181]

[0182]

[0183] Where R 0 and X 0 has the meanings shown in formula II.

[0184] R 0 Preferably, X represents an alkyl radical having 1 to 6 C atoms. 0 Preferably it represents F and OCF3, furthermore OCHF2, CF3, OCF=CF2 and OCH=CF2.

[0185] The compound of formula VI is preferably selected from the following sub-formulae:

[0186]

[0187]

[0188] Where R 0 and X 0 has the meanings shown in formula II.

[0189] R 0 Preferably, X represents an alkyl radical having 1 to 6 C atoms. 0 Preferably represents F, and further represents OCF3, CF3, CF=CF2, OCHF2 and OCH=CF2;

[0190] The compound of formula VII is preferably selected from the following sub-formulae:

[0191]

[0192] Where R 0 and X 0 has the meanings shown in formula II.

[0193] R 0 Preferably, X represents an alkyl radical having 1 to 6 C atoms. 0 Preferably it represents F, furthermore it represents OCF3, OCHF2 and OCH=CF2.

[0194] In some embodiments, the LC medium further comprises one or more compounds selected from the following formulae:

[0195]

[0196] in

[0197] R 0 and X 0 Each independently has one of the meanings shown in formula II,

[0198] L 1-4 Each independently represents H or F,

[0199] Y 0 represents H or CH3, preferably H,

[0200] X 0 Preferably, F, Cl, CF3, OCF3 or OCHF2,

[0201] R 0 Preferably it denotes alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl, each having up to 6 C atoms.

[0202] Very preferably, the LC media according to the invention comprise one or more compounds of the formula XXa:

[0203]

[0204] Where R 0has the meaning shown in formula LP1. 0 Preferably it denotes straight-chain alkyl, in particular ethyl, n-propyl, n-butyl or n-pentyl, very particularly preferably n-propyl.

[0205] The compounds of the formula XX, in particular of the formula XXa, are preferably used in the LC media according to the invention in an amount of 0 to 15% by weight, particularly preferably 1 to 10% by weight.

[0206] Very preferably, the LC media according to the invention comprise one or more compounds of the formula XXIa:

[0207]

[0208] Where R 0 has the meaning shown in formula LP1. 0 Preferably it denotes straight-chain alkyl, in particular ethyl, n-propyl, n-butyl or n-pentyl, very particularly preferably n-propyl.

[0209] The compounds of the formula XXI, in particular of the formula XXIa, are preferably used in the LC media according to the invention in an amount of 1 to 15% by weight, particularly preferably 2 to 10% by weight.

[0210] It is further preferred that the LC media according to the invention comprise one or more compounds of the formula XXIIIa:

[0211]

[0212] Where R 0 has the meaning shown in formula LP1. 0 Preferably it denotes straight-chain alkyl, in particular ethyl, n-propyl, n-butyl or n-pentyl, very particularly preferably n-propyl, or cycloalkyl, in particular cyclopentyl.

[0213] Preferred specific compounds of formula XXIIIa include in particular

[0214]

[0215] The compounds of the formula XXIII, in particular of the formula XXIIIa, are preferably used in the LC media according to the invention in an amount of 0.5 to 5% by weight, particularly preferably 0.5 to 2% by weight.

[0216] The LC medium may additionally comprise one or more compounds of the formula XXIV:

[0217]

[0218] Where R 0 , X 0 and L 1-6 has the meanings shown in formula III, s represents 0 or 1, and

[0219] express

[0220]

[0221] In Formula XXIV, X 0 It may also represent an alkyl radical having 1 to 6 C atoms or an alkoxy radical having 1 to 6 C atoms. The alkyl or alkoxy radical is preferably straight-chain.

[0222] R0 preferably represents an alkyl radical having 1 to 6 C atoms. X0 preferably represents F;

[0223] The compound of formula XXIV is preferably selected from the following sub-formulae:

[0224]

[0225]

[0226] wherein R0, X0 and L1 have the meanings indicated in formula III. R0 preferably represents an alkyl group having 1 to 6 C atoms. X0 preferably represents F, and L1 is preferably F;

[0227] Preferably

[0228]

[0229] R 0 is a straight-chain alkyl or alkenyl group having 2 to 6 C atoms;

[0230] The LC medium may further comprise one or more compounds of the following formula:

[0231]

[0232] Where R 1 and X 0 Respectively have the formula II for R 0 and X 0 Meaning of the indication. 1 Preferably, X represents an alkyl radical having 1 to 6 C atoms. 0 Preferably, it represents F or Cl. In formula XXIV, X 0 Very particularly preferably it represents Cl.

[0233] The LC medium may further optionally comprise one or more compounds of the following formulae:

[0234]

[0235] Where R 1 and X0 Respectively have the formula II for R 0 and X 0 Meaning of the indication. 1 Preferably, X represents an alkyl radical having 1 to 6 C atoms. 0 Preferably represents F. The LC media according to the invention particularly preferably comprise one or more compounds of the formula XXIX, in which X 0 Preferably it represents F.

[0236] The compounds of the formulae XXV-XXX are preferably used in the LC media according to the invention in amounts of 1 to 20% by weight, particularly preferably 1 to 15% by weight. Particularly preferred LC media comprise at least one compound of the formula XXIX.

[0237] Very preferably, the LC media according to the invention comprise one or more compounds of the formula XXIXa:

[0238]

[0239] Where R 1 has the meaning indicated in formula II, preferably denotes straight-chain alkyl, in particular ethyl, n-propyl, n-butyl or n-pentyl, very particularly preferably n-propyl.

[0240] The compound of the formula XXIXa is preferably used in the LC media according to the invention in an amount of from 1 to 15% by weight, particularly preferably from 2 to 10% by weight.

[0241] The LC medium may further comprise one or more pyrimidine or pyridine compounds of the following formula:

[0242]

[0243] Where R 1 and X 0 Respectively have the formula II for R 0 and X 0 Meaning of the indication. 1 Preferably, X represents an alkyl radical having 1 to 6 C atoms. 0 Preferably it represents F. The medium according to the invention may optionally contain one or more compounds of the formula XXX-1, in which X 0 Preferably it represents F. The compounds of the formulae XXX-1 to XXX-3 can be used in the LC media according to the invention in amounts of 1 to 20% by weight, particularly preferably 1 to 15% by weight.

[0244] Preferably, the LC medium contains, in addition to the compounds of formula G, LP1 and LP2, one or more compounds selected from the following formulae:

[0245]

[0246]

[0247] in

[0248] "alkyl" and "alkyl*" each independently represent an alkyl group having 1 to 6 C atoms;

[0249] "Alkenyl" and "alkenyl*" each independently of one another represent an alkenyl group having 2 to 6 C atoms.

[0250] Very particular preference is given to compounds of the formulae Z1 and Z2.

[0251] Preferred compounds of formula Z1 to Z6 are those selected from the following sub-formulae:

[0252]

[0253]

[0254]

[0255] In a further preferred embodiment, the LC medium contains one or more compounds of the formula Z1 or preferred subformulae thereof and / or one or more compounds selected from the group consisting of the formulae Z2, Z3, Z4 and Z5 or preferred subformulae thereof.

[0256] Preferably, the total proportion of compounds of the formulae Z1, Z2, Z3, Z4, Z5 and Z6 or their subformulae, such as CC-3-V, in the medium is from 10 to 65% by weight, very preferably from 20 to 60% by weight, most preferably from 25 to 55% by weight. In a more preferred embodiment, the compound of the formula Z1-1 is used in a concentration of 10 to 60% by weight, more preferably from 25 to 50% by weight, based on the total weight of the LC medium. In a further preferred embodiment, the LC medium comprises a total of 50 to 70% by weight of compounds represented by the formulae Z1-1 and Z4-2.

[0257] Preferably, the medium contains 1, 2 or 3 compounds selected from the group consisting of formulae Z1, Z2, Z3 and Z4 or subformulae thereof.

[0258] The LC medium may additionally comprise one or more compounds of the following general formula:

[0259]

[0260] in

[0261] R 1 and R 2 Each independently represents C 1-6 -alkyl, C 1-6 -alkoxy or C2-6 -alkenyl.

[0262] The compound of formula XII is preferably selected from the following sub-formulae:

[0263]

[0264]

[0265] Here, "alkyl" and "alkyl*" each independently represent methyl, butyl, pentyl or hexyl.

[0266] Particularly preferred are compounds of formula XIIa and XIIc. In formula XIIb, "alkyl" preferably represents, independently of one another, n-C3H7, n-C4H9 or n-C5H 11 , especially n-C3H7. In formula XIIc, "alkyl" preferably represents n-C3H7, and "alkyl*" is preferably CH3 or n-C3H7.

[0267] Particularly preferred compounds of Formula XII are described by the following structure:

[0268]

[0269] The LC medium may additionally comprise one or more compounds selected from the following formulae:

[0270]

[0271] Where L 1 and L 2 has the meaning shown in formula LP1, and R 1 and R 2 each independently of one another represents n-alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl, each having up to 6 C atoms, and preferably each independently of one another represents an alkyl group having 1 to 6 C atoms; in the compound of formula XIV, the substituent R 1 and R 2 At least one of preferably represents an alkenyl group having 2 to 6 C atoms.

[0272] The LC medium may further optionally comprise one or more compounds of the formula XIV, in which the substituent R 1 and R 2 At least one of represents an alkenyl group having 2 to 6 C atoms, preferably selected from those of the following sub-formulae:

[0273]

[0274] Therein, "alkyl" and "alkyl*" have the meanings indicated above and each independently of one another preferably denote methyl, ethyl or propyl.

[0275] The compound of formula XIV is preferably selected from the following sub-formulae:

[0276]

[0277]

[0278] Very preferred are compounds of the formulae XIVd-1, XIVe-1, XIVe-2 and XIVe-3.

[0279] The LC medium may further optionally contain one or more compounds of the formula XV, in which the substituent R 1 and R 2 At least one of represents an alkyl or alkoxy group having 2 to 6 C atoms, preferably those selected from the following sub-formulae:

[0280]

[0281] Therein "alkyl" has the meaning indicated above and each independently of one another preferably denotes methyl, ethyl or propyl.

[0282] In yet a further embodiment, the LC medium comprises one or more compounds of formula XVI:

[0283]

[0284] Where R 1 and R 2 have the meanings indicated in formula G and preferably each independently of one another represent an alkyl group having 1 to 6 C atoms. L represents H or F.

[0285] Particularly preferred compounds of formula XVI are those of the following sub-formula:

[0286]

[0287]

[0288] in

[0289] "Alkyl" and "alkyl*" each independently of the other denote a straight-chain alkyl radical having 1 to 6 C atoms, in particular ethyl, propyl or pentyl, and

[0290] "Alkenyl" and "alkenyl*" each independently of one another denote straight-chain alkenyl having 2 to 6 C atoms, in particular CH2=CHC2H4, CH3CH=CHC2H4, CH2=CH and CH3CH=CH.

[0291] Particularly preferred are compounds of the formulae XVIb and XVIc. Very particularly preferred are compounds of the following sub-formulae:

[0292]

[0293]

[0294] Very preferred are compounds of formula XVIc-2.

[0295] The LC medium may optionally comprise one or more compounds of the formula:

[0296]

[0297] in

[0298] R 1 and R 2 Each has the meaning indicated in formula G and preferably each independently represents an alkyl group having 1 to 6 C atoms. L represents H or F.

[0299] Very preferred are compounds of formula XVIIa, wherein L is H. Very preferred are compounds of formula XVIIb, wherein L is F.

[0300] The LC medium may additionally comprise one or more compounds of the formula:

[0301]

[0302] Among them, L, R 1 and R 2 Respectively have the formula LP1 for L1 and the formula U for R 3 and R 4 Meaning of the indication. 1 and R 2 Preferably it denotes alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl, each having up to 6 C atoms.

[0303] Particularly preferred compounds of formula XXXII are those of the following sub-formula:

[0304]

[0305] in

[0306] "Alkyl" and "alkyl*" each independently of the other denote a straight-chain alkyl radical having 1 to 6 C atoms, in particular ethyl, propyl or pentyl, and

[0307] "Alkenyl" denotes straight-chain alkenyl having 2 to 6 C atoms, in particular CH2=CHC2H4, CH3CH=CHC2H4, CH2=CH and CH3CH=CH.

[0308] Very particular preference is given to compounds of the following sub-formula:

[0309]

[0310]

[0311] In some further embodiments, the LC medium comprises one or more compounds of the formula:

[0312]

[0313] Where R 1 and R 2 have the meanings indicated in formula G and preferably each independently of one another represent an alkyl group having 1 to 6 C atoms.

[0314] Compounds of formula ST

[0315] In some preferred embodiments of the present invention, the LC medium may further comprise one or more additives which are compounds of the general formula ST:

[0316]

[0317] The substituents have the following meanings:

[0318] express

[0319] X2 1 , X 22 Each independently represents -O-, -CH2-, -CHR 23 -or-NR 23 -;

[0320] R 21 and R 22 Each independently represents an H atom or an alkyl or alkoxy group having 1 to 12 C atoms, an alkenyl, alkynyl, alkenyloxy or alkoxyalkyl group having 2 to 12 C atoms or a cycloalkyl group having 3 to 12 C atoms, wherein one or more non-adjacent CH2 groups are optionally replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- is substituted in such a way that the O atoms are not directly attached to one another and in which one or more H atoms may be replaced by a halogen atom or a cycloalkyl or cycloalkoxy group having 3 to 12 C atoms in which one or more H atoms may be replaced by a halogen atom;

[0321] R 23 represents an H atom, an alkyl group having 1 to 10 C atoms, or an alkoxy group;

[0322] r represents 0 or 1.

[0323] LC media comprising compounds of the following subformulae ST-1, ST-2 and ST-3 exhibit particularly high long-term thermal and UV stability:

[0324]

[0325] The substituents have the following meanings:

[0326] express

[0327] R 21 and R 22 each independently of one another represents an H atom or an alkyl or alkoxy group having 1 to 7 C atoms; and

[0328] r represents 0 or 1.

[0329] In a particularly preferred embodiment, the compound of the general formula ST can be selected from the following specific structures:

[0330]

[0331]

[0332]

[0333]

[0334] In a further preferred embodiment, the LC media according to the invention may comprise at least one further sterically hindered phenol mentioned in Table B below.

[0335] Compounds of formula H

[0336] The LC medium may optionally contain one or more additives which are compounds of formula H

[0337]

[0338] in

[0339] R 11 each independently of one another represents an H atom, F, an alkyl group having 1 to 20 C atoms, in which one -CH2- group or, if present, multiple -CH2- groups may be replaced by -O- or -C(=O)-, but two adjacent -CH2- groups may not be replaced by -O-, and one or, if present, multiple -CH2- groups may be replaced by -CH=CH- or -C≡C-, and in which one or more H atoms may be replaced by F, OR 13 、N(R 13 )(R 14 ) or R 15 Replacement;

[0340] R 12 each independently represents an H atom, an alkyl group having 1 to 20 C atoms, in which one -CH2- group or multiple -CH2- groups can be replaced by -O- or -C(=O)-, but two adjacent -CH2- groups cannot be replaced by -O-, a hydrocarbon group containing cycloalkyl or alkylcycloalkyl units and in which one -CH2- group or multiple -CH2- groups can be replaced by -O- or -C(=O)-, but two adjacent -CH2- groups cannot be replaced by -O-, and in which one H atom or multiple H atoms can be replaced by F, OR 13 、N(R 13 )(R 14 ) or R 15 substituted, or aromatic or heteroaromatic hydrocarbon radicals in which one or more H atoms may be replaced by OR 13 、N(R 13 )(R 14 ) or R 15 Replacement;

[0341] R 13 and R 14 each independently of one another represents an alkyl or acyl group having 1 to 10 C atoms or an aromatic hydrocarbon or carboxylic acid group having 6 to 12 C atoms;

[0342] R 15 each independently of one another represents an alkyl group having 1 to 10 C atoms, in which one -CH2- group or multiple -CH2- groups may be replaced by -O- or -C(=O)-, but two adjacent -CH2- groups may not be replaced by -O-;

[0343] R 16 are each independently an H atom, an alkyl or alkoxy group having 1 to 10 C atoms, an O-cycloalkyl group having 3 to 12 C atoms, an O · or OH;

[0344] S 11 and S 12each independently of one another represents an alkylene radical having 1 to 20 C atoms, in which one -CH2- group or, if present, multiple -CH2- groups may be replaced by -O- or -C(=O)-, but two adjacent -CH2- groups may not be replaced by -O-, and in which one H atom or multiple H atoms may be replaced by F, OR 13 、N(R 13 )(R 14 ) or R 15 Replace, or represent a single bond;

[0345] Y 11 To Y 14 each independently represents a methyl group or an ethyl group;

[0346] X 11 Indicates C;

[0347] Z 11 To Z 14 Each independently represents -O-, -(C=O)-, -O-(C=O)-, -(C=O)-O-, -O-(C=O)-O-, -(NR 13 )-、-NR 13 -(C=O)- or a single bond, if S 11 is a single bond, then Z 11 and Z 12 Different at the same time means -O-; if S 12 is a single bond, Z 13 and Z 14 If q is not equal to 0, then Z 12 and Z 13 Different means -O-;

[0348] p means 1 or 2;

[0349] q represents 0 or 1;

[0350] o represents (3-p);

[0351] n represents an integer from 1 to 10;

[0352] m represents an integer from 0 to 8; wherein

[0353] n*p represents an integer from 1 to 10, preferably from 3 to 8; and

[0354] represents an organic moiety having (m+n) bonding sites. In some preferred embodiments of the present invention, in the compound of formula H,

[0355] express

[0356] (biphenyl-1,1′,3,3′-tetrayl) or

[0357] (Benzene-1,2,4,5-tetrayl)

[0358] express (Benzene-1,3,5-triyl) or

[0359] (Benzene-1,2,4-triyl),

[0360] That is, 1,2-diyl, 1,3-diyl, 1,4-diyl, 1,5-diyl, 1,6-diyl, 1,7-diyl, 1,8-diyl,

[0361] (1,4-phenylene),

[0362] (1,3-phenylene),

[0363] (1,2-phenylene) or

[0364] (trans-1,4-cyclohexylene) and / or

[0365] in

[0366] -Z 12 -S 11 -Z 11 -In each occurrence, it represents -O-, S independently of each other 11 -O-, -OS 11 -O-, -(C=O)-OS 11 -O-, -O-(C=O)-S 11 -O-, -O-(C=O)-S 11 -(C=O)-O-, -OS 11 -(C=O)-O-, -(C=O)-OS 11 -C, -(C=O)-OS 11 -O-(C=O)- or -(NR 13 )-S 11 -O-、-(NR 13 -C(=O)-S 11 -(C=O)-O or a single bond, preferably -O-, -S 11 -O-, -OS 11 -O-, -(C=O)-OS11 -O-, -O-(C=O)-S 11 -O-or-OS 11 -(C=O)-O-; and / or

[0367] S 11 preferably denotes alkylene having 1 to 20 C atoms; and / or

[0368] R 11 If present, it represents alkyl, alkoxy or H, preferably H or alkyl; and / or

[0369] R 12 represents H, methyl, ethyl, propyl, isopropyl or 3-heptyl, or cyclohexyl.

[0370] In a preferred embodiment of the present application, in the compound of formula H,

[0371]

[0372] represents a group selected from the following formulae:

[0373]

[0374] In a further preferred embodiment of the present application, in the compound of formula H,

[0375]

[0376] represents a group selected from the following formula

[0377]

[0378] In another further preferred embodiment of the invention, in compounds of formula H in which p preferably represents 1,

[0379]

[0380] express Optimized-OS 11 -O-, -S 11 -O-or-OS 11 -, particularly preferably -OS 11 -O- or -S 11 -O-.

[0381] In a further preferred embodiment of the invention, in the compounds of formula H, the group

[0382]

[0383] represents a group selected from the following formula

[0384]

[0385]

[0386] In a further preferred embodiment of the invention - wherein p is 2, which may be the same as or different from those described above, in the compounds of formula H,

[0387]

[0388] represents a group selected from the following formula

[0389]

[0390] In another further preferred embodiment of the present invention, which may be the same as or different from those described above, in the compound of formula H, the group

[0391]

[0392] In each case, they are expressed independently of each other.

[0393]

[0394] Best

[0395]

[0396] The compounds of the following general formulae H-1-1, H-1-2 and H-1-3 have been shown to be particularly effective UV stabilizers in LC mixtures, in particular with regard to VHR stability:

[0397]

[0398] Among them, ZG, R 16 and n are as defined above and n represents an integer from 1 to 8. These compounds are very suitable as stabilizers in LC mixtures and stabilize the VHR of the mixtures upon UV exposure.

[0399] In a particularly preferred embodiment, the one or more compounds of formula H may be selected from the following compounds of formulae H-2-1 to H-2-6:

[0400]

[0401]

[0402] in

[0403] R 11each independently represents an H atom, an alkyl group having 1 to 20 C atoms, in which one -CH2- group or, if present, multiple -CH2- groups may be replaced by -O- or -C(=O)-, but two adjacent -CH2- groups may not be replaced by -O-, and one or, if present, multiple -CH2- groups may be replaced by -CH=CH- or -C≡C-, and in which one or more H atoms may be replaced by F, OR 13 、N(R 13 )(R 14 ) or R 15 Replacement;

[0404] R 16 Represents H atom or O · ;

[0405] n represents an integer from 0 to 12; and

[0406] S 11 and S 12 each independently of one another represents an alkylene radical having 1 to 20 C atoms, in which one -CH2- group or, if present, multiple -CH2- groups may be replaced by -O- or -C(=O)-, but two adjacent -CH2- groups may not be replaced by -O-, and in which one H atom or multiple H atoms may be replaced by F, OR 13 、N(R 13 )(R 14 ) or R 15 Instead, or represents a single bond.

[0407] In a preferred embodiment of the present invention, the LC media according to the invention comprise one or more compounds of the formula H which are in each case selected from the compounds of the following formulae:

[0408]

[0409]

[0410]

[0411]

[0412]

[0413]

[0414]

[0415]

[0416] The preferred content of the one or more compounds of the formula H in the LC medium depends inter alia on the intrinsic chemical stability of the LC medium and on the nature of the compounds of the formula H. Compounds of the formula H in which R16 represents O·, which are known as NO-radical HALS, are preferably used in a proportion of 50 to 1000 ppm, based on the weight of the LC medium. Compounds of the formula H in which R16 represents an H atom, which are known as NH-radical HALS, are advantageously used in a proportion of 50 to 2000 ppm, based on the weight of the LC medium.

[0417] Further preferred LC media are selected from the following preferred embodiments, including any combination thereof:

[0418] Combinations of compounds of formula G, LP1 and LP2 with compounds of formula LP1, Z1 to Z7 and II and / or III;

[0419] Combinations of compounds of formula G, LP1 and LP2 with compounds of formula LP2, Z1 to Z7 and II and / or III;

[0420] • Combinations of compounds of formula G, LP1 and LP2 with compounds of formula LP1, LP2, II and / or III and compounds of formula Z1 and Z4.

[0421] -LC medium comprises one or more compounds of formula G, LP1 and LP2, II and / or III and one or more compounds selected from formula Z1, Z2, Z3, Z4, Z5, V, VI, VII, VIII, XIV, XV, XVI, XVIIa, XVIIb, XVIIc, XVIII, XIX, XX, XXI, XXIII, XXIV, XXV, XXVI, XXVII, XXVIII, XXIX, XXX, XXX-1, XXX-2, XXX-3, XXXII, XXXIII and S and subformulae thereof.

[0422] -LC medium comprises one or more compounds of formula G, LP1 and LP2, II and / or III and one or more compounds selected from formula Z1, Z2, Z3, Z4, Z5, IV, VI, XII, XIV, XVI, XVIIa, XVIIb, XVIIc, XX, LP1-1, XXIII, XXIX and S and subformulae thereof.

[0423] - The LC medium contains one or more compounds selected from the formulae II-1, II-2 and II-3, very preferably selected from the formulae II-1 and II-2. The individual concentration of each of these compounds is preferably 2 to 15% by weight. The total concentration of these compounds is preferably 5 to 25% by weight.

[0424] - The LC medium contains one or more compounds selected from the group consisting of formulae III-1, III-4, III-6, III-16, III-19 and III-20, very preferably selected from the group consisting of formulae III-1, III-6, III-16 and III-20. The individual concentration of each of these compounds is preferably 2 to 15% by weight. The total concentration of these compounds is preferably 5 to 30% by weight.

[0425] -LC medium contains one or more compounds of formula IV, preferably selected from formula IVa or IVc, very preferably selected from formula IVa-1 or IVc-1, most preferably formula IVc-1. The individual concentration of each of these compounds is preferably 2 to 15% by weight. The total concentration of these compounds is preferably 5 to 20% by weight.

[0426] - The LC medium contains one or more compounds of the formula VI, preferably selected from the formula VIb. The individual concentration of each of these compounds is preferably 1 to 20% by weight. The total concentration of these compounds is preferably 5 to 20% by weight.

[0427] The LC medium comprises one or more compounds of the formula Z1, preferably selected from the formula Z1-1. The total concentration of these compounds is preferably from 1 to 60% by weight, more preferably from 5 to 50% by weight.

[0428] The LC medium comprises one or more compounds of the formula Z2, preferably selected from the formulae Z2-1 and Z2-2. The total concentration of these compounds is preferably from 2 to 35% by weight, very preferably from 3 to 25% by weight.

[0429] The LC medium comprises 5 to 20% by weight of a compound of the formula Z3, preferably of the formula Z3-1.

[0430] The LC medium comprises 5 to 20% by weight of a compound of the formula Z4, preferably of the formula Z4-1.

[0431] The LC medium comprises from 10 to 65% by weight, very preferably from 20 to 60% by weight, of the compound of the formula Z5.

[0432] - The LC medium comprises one or more compounds of the formula LP1-1, preferably of the formula LP1-1a or LP2-1b, very preferably of the formula LP1-1a. The concentration of these compounds is preferably from 2 to 15% by weight.

[0433] The LC medium comprises 1 to 15% by weight of the compound of the formula LP2-1b.

[0434] The LC medium comprises one or more compounds of the formula XII, preferably of the formula XIIa or XIIb, very preferably of the formula XIIa, most preferably of the formula XIIa-1. The concentration of these compounds is preferably from 2 to 15% by weight.

[0435] The LC medium comprises 1 to 15% by weight of the compound of the formula XIIb.

[0436] The LC medium comprises one or more compounds of the formula XIV, preferably of the formula XIVd, very preferably of the formula XIVd-1. The concentration of these compounds is preferably from 2 to 10% by weight.

[0437] - The LC medium comprises one or more compounds of the formula XVIb, preferably of the formula XVIb-1, XVIb-2 and / or XVIb-3. The concentration of these compounds is preferably from 2 to 15% by weight.

[0438] - The LC medium comprises one or more compounds of the formula XVIc, preferably of the formula XVIc-1, XVIc-2 and / or XVIc-3. The concentration of these compounds is preferably from 2 to 20% by weight.

[0439] The LC medium comprises one or more compounds selected from the formulae XVIIa, XVIIb and XVIIc, very preferably compounds of the formula XVIIa wherein L is H and XVIIb wherein L is F. The total concentration of these compounds is preferably from 0.5 to 5% by weight.

[0440] - The LC medium comprises one or more compounds of the formula XX, preferably of the formula XXa. The concentration of these compounds is preferably from 2 to 10% by weight.

[0441] The LC medium comprises one or more compounds of the formula XXI, preferably of the formula XXIa. The concentration of these compounds is preferably from 2 to 10% by weight.

[0442] - The LC medium comprises one or more compounds of the formula XXIII, preferably of the formula XXIIIa. The concentration of these compounds is preferably from 0.5 to 5% by weight.

[0443] - The LC medium comprises one or more compounds of the formula XXIX, preferably of the formula XXIXa. The concentration of these compounds is preferably from 2 to 10% by weight.

[0444] The LC medium comprises one or more compounds of the formula XXX. The concentration of these compounds is preferably from 2 to 10% by weight.

[0445] The LC medium comprises one or more compounds of the formula XII. The concentration of these compounds is preferably from 2 to 10% by weight.

[0446] -LC medium comprises one or more compounds of formula G, preferably formula G-1, LP1 and LP2, II and / or III, one or more compounds selected from formula Z1, Z2 and Z3 or their subformulas, one or more compounds selected from formula XIV, one or more compounds selected from formula IV, VI, XX, XXIII and XXIX or their subformulas, and one or more compounds selected from formula LP2-1, XVI, XVIIa, XVIIb, XVIIc or their subformulas.

[0447] -LC medium comprises one or more compounds of formula G, preferably formula G-1, LP1 and LP2, II and / or III, one or more compounds selected from formula Z1, Z2, Z3, Z4 and Z5 or their subformulas, one or more compounds selected from formula XIVd or their subformulas, one or more compounds selected from formula IVc, VIb, XXa, XXIIIa and XXIXa or their subformulas, and one or more compounds selected from formula LP1-1b, XVIb, XVIc, XVIIa, XVIIb, XVIIc or their subformulas.

[0448] -LC medium comprises one or more compounds of formula G, preferably formula G-1, LP1 and LP2, II and / or III, one or more compounds selected from formula Z1, Z2 and Z3 or their subformulas, one or more compounds of formula Y (preferably selected from formula Y1 and Y2), one or more compounds selected from formula XIV, one or more compounds selected from formula II, III, IV, VI, XX, XXIII and XXIX or their subformulas, and one or more compounds selected from formula LP2-1, XVI, XVIIa, XVIIb, XVIIc or their subformulas.

[0449] -LC medium comprises one or more compounds of formula G, preferably compounds of formula G-1, LP1 and LP2, one or more compounds selected from formula Z1, Z2, Z3, Z4 and Z5 or subformulas thereof, one or more compounds of formula B (preferably selected from formula B1, B2 and B3), one or more compounds of formula XIVd or subformulas thereof, one or more compounds selected from formula II, III, IVc, VIb, XXa, XXIIIa and XXIXa or subformulas thereof, and one or more compounds selected from formula LP1-1b, XVIb, XVIc, XVIIa, XVIIb, XVIIc or subformulas thereof.

[0450] - In addition to compounds of formula G, LP1 and LP2, the LC medium further comprises a compound selected from compounds of formula Z1, Z2, Z3, IV, LP1-1, XIV, XVI, XVIIa, XVIIb, XVIIc, XXI, XXIII, XXIX, XXX and XXIV or subformulae thereof.

[0451] - In addition to compounds of formula G, LP1 and LP2, the LC medium further comprises a compound selected from compounds of formula Z1, Z2, Z3, IV, LP2-1, XIV, XVI, XVIIa, XVIIb, XVIIc, XXI, XXIII, XXIX, XXX and XXIV or subformulae thereof.

[0452] The proportion of the compound of the formula G in the LC medium is from 1 to 30% by weight, very preferably from 2 to 25% by weight and most preferably from 2 to 20% by weight.

[0453] The proportion of compounds of the formulae Z1, Z2, Z3, Z4 and Z5 or their subformulae in the LC medium as a whole is from 10 to 65% by weight, very preferably from 20 to 60% by weight.

[0454] The proportion of the compound of the formula Y or a subformulae thereof in the LC medium as a whole is from 0 to 15% by weight, very preferably from 2 to 10% by weight.

[0455] The proportion of the compound of the formula B or its subformulae in the LC medium as a whole is from 0 to 15% by weight, very preferably from 2 to 10% by weight.

[0456] The proportion of the compounds of the formulae II, III, IV-VIII, XVIII-XXIII and XXVII-XXX in the LC medium as a whole is from 30 to 60% by weight.

[0457] The proportion of the compounds of the formulae XIV and XV in the LC medium as a whole is from 40 to 70% by weight.

[0458] The proportion of the compounds of the formulae XIV, XVIIa-c and XXXII in the LC medium as a whole is from 0.5 to 15% by weight.

[0459] The term "alkyl" or "alkyl*" in the present application encompasses straight-chain and branched alkyl groups having 1 to 6 carbon atoms, in particular the straight-chain groups methyl, ethyl, propyl, butyl, pentyl and hexyl. Groups having 2 to 5 carbon atoms are generally preferred.

[0460] The term "alkenyl" or "alkenyl*" encompasses straight-chain and branched alkenyl groups having 2 to 6 carbon atoms, in particular straight-chain groups. Preferred alkenyl groups are C2-C7-1E-alkenyl, C4-C6-3E-alkenyl, in particular C2-C6-1E-alkenyl. Examples of particularly preferred alkenyl groups are vinyl, 1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hexenyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl, 4-pentenyl, 4Z-hexenyl, 4E-hexenyl and 5-hexenyl. Groups having up to 5 carbon atoms are generally preferred, in particular CH2=CH, CH3CH=CH.

[0461] The term "fluoroalkyl" preferably encompasses straight-chain groups with terminal fluorine, i.e. fluoromethyl, 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl, 5-fluoropentyl, 6-fluorohexyl and 7-fluoroheptyl. However, other positions of fluorine are not excluded.

[0462] The term "oxaalkyl" or "alkoxy" preferably encompasses groups of the formula C n H 2n+1 -O-(CH2) m wherein n and m each independently represent 1 to 6. m may also represent 0. Preferably, n=1 and m=1 to 6 or m=0 and n=1 to 3. Further preferably, the alkoxy or oxaalkyl group may further contain one or more additional O atoms, so that the oxygen atoms are not directly connected to each other.

[0463] By R in formula II and III 0 and X 0 By suitable choice of the meaning of , the addressing time, the threshold voltage, the steepness of the transmission characteristic line, etc. can be varied in the desired manner. For example, 1E-alkenyl, 3E-alkenyl, 2E-alkenyloxy, etc. generally lead to shorter addressing times, an improved nematic tendency and a higher ratio between the elastic constants K3 (bending) and K1 (bending) compared to alkyl and alkoxy groups. 4-alkenyl, 3-alkenyl, etc. generally give lower threshold voltages and lower K3 / K1 values ​​compared to alkyl and alkoxy groups. The LC media according to the invention are particularly distinguished by high Δε values ​​and therefore have significantly faster response times compared to the LC media of the prior art.

[0464] The optimum mixing ratio of the compounds of the above-mentioned formulae depends essentially on the desired properties, on the choice of the components of the above-mentioned formulae and on the choice of any further components that may be present.

[0465] A suitable mixing ratio within the range given above can be easily determined according to the circumstances.

[0466] The total amount of compounds of the above-mentioned formulae in the LC medium according to the invention is not critical. The LC medium may therefore comprise one or more further components to optimize various properties. However, the higher the total concentration of compounds of the above-mentioned formulae, the greater the effect observed on the desired improvement of the properties of the medium.

[0467] In a particularly preferred embodiment, the LC media according to the invention comprise compounds of the formulae IV to VIII (preferably IV and V), in which X 0 Denotes F, OCF3, OCHF2, OCH=CF2, OCF=CF2 or OCF2-CF2H. The favorable synergy with the compounds of formula G, LP1 and LP2, II and III leads to particularly advantageous properties. In particular, LC media comprising compounds of formula G, LP1 and LP2, II and III are distinguished by their low threshold voltage.

[0468] The compounds of the abovementioned formulae and subformulae thereof which can be used in the LC media according to the invention are known or can be prepared analogously to known compounds.

[0469] The present invention also relates to a process for preparing an LC medium as described above and below by mixing one or more compounds of the formula G with one or more compounds of the formula LP1 and LP2 and one or more compounds selected from the group consisting of the formulae II, III, Z1, Z2, Z3, Z4, IV, VI, XIV, LP2-1, XVI, XVIIa, XVIIb, XVIIc, XX, XXIII and XXIX.

[0470] The LC medium of the present invention may optionally contain one or more polymerisable compounds. The polymerisable compounds are preferably selected from the group consisting of formula M

[0471] R a -B 1 -(Z b -B 2 ) m -R b M

[0472] The substituents, identically or differently on each occurrence and independently of one another, have the following meanings:

[0473] R a and R b represents P, P-Sp-, H, F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, SF5 or a straight-chain or branched alkyl radical having 1 to 25 C atoms, wherein, in addition, one or more non-adjacent CH2 groups may each be replaced independently of one another by -C(R 0 )=C(R 00)-、-C≡C-、-N(R 00 )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that O and / or S atoms are not directly connected to one another, and wherein, in addition, one or more H atoms may be replaced by F, Cl, Br, I, CN, P or P-Sp-, wherein if B 1 and / or B 2 Contains saturated C atoms, R a and / or R b It can also represent a group in which a spiro ring is attached to such a saturated C atom;

[0474] The substituent R a and R b At least one of them represents or contains a group P or P-Sp-;

[0475] P represents a polymerizable group;

[0476] Sp represents a spacer group or a single bond;

[0477] B 1 and B 2 represents an aromatic, heteroaromatic, alicyclic or heterocyclic group, preferably having 4 to 25 ring atoms, which may also contain fused rings, and which is unsubstituted or mono- or polysubstituted by L;

[0478] Z b Represents -O-, -S-, -CO-, -CO-O-, -OCO-, -O-CO-O-, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -(CH2) n1 -, -CF2CH2-, -CH2CF2-, -(CF2) n1 -, -CH=CH-, -CF=CF-, -C≡C-, -CH=CH-COO-, -OCO-CH=CH-, CR 0 R 00 or single key;

[0479] R 0 and R 00 each independently of one another represents H or an alkyl group having 1 to 12 C atoms;

[0480] m represents 0, 1, 2, 3 or 4;

[0481] n1 means 1, 2, 3 or 4;

[0482] L represents P, P-Sp-, OH, CH2OH, F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, -C(=O)N(R x )2, -C(=O)Y 1 、-C(=O)R x 、-N(R x )2, optionally substituted silyl, optionally substituted aryl having 6 to 20 C atoms, or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, wherein, in addition, one or more H atoms may be replaced by F, Cl, P or P-Sp-;

[0483] P and Sp have the meanings shown in formula M above;

[0484] Y 1 represents halogen;

[0485] R x represents P, P-Sp-, H, halogen, straight-chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein, in addition, one or more non-adjacent CH2 groups can be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that the O and / or S atoms are not directly connected to one another, and wherein, in addition, one or more H atoms can be replaced by F, Cl, P or P-Sp-, optionally substituted aryl or aryloxy having 6 to 40 C atoms or optionally substituted heteroaryl or heteroaryloxy having 2 to 40 C atoms.

[0486] It is further preferred that the LC media according to the present invention comprise one or more polymerisable compounds selected from Table H below.

[0487] Preferably, the proportion of polymerizable compounds (preferably selected from formula M and table H) in the LC medium is from 0.01 to 5%, very preferably from 0.05 to 1%, most preferably from 0.1 to 0.5%.

[0488] It has been observed that the addition of one or more polymerizable compounds, such as those selected from Formula M and Table H, to the LC medium brings about advantageous properties, such as fast response time. Such LC media are particularly suitable for use in PSA displays, where they exhibit low image sticking, fast and complete polymerization, rapid generation of low pretilt angles (which are stable after UV exposure), high reliability, high VHR values ​​after UV exposure and high birefringence. By appropriate choice of polymerizable compounds, it is possible to increase the absorption of the LC medium at longer UV wavelengths, so that it is possible to use such longer UV wavelengths for polymerization, which is beneficial for the display manufacturing process.

[0489] The polymerizable group P is a group suitable for polymerization, such as free radical or ionic chain polymerization, polyaddition or polycondensation, or for polymer-analogous conversion reactions, such as addition or condensation to the polymer backbone. Particularly preferred are groups for chain polymerization, in particular those containing a C=C double bond or a -C≡C-triple bond, and groups suitable for ring-opening polymerization, such as oxetane or epoxy groups.

[0490] Preferred groups P are selected from CH2=CW 1 -CO-O-, CH2=CW 1 -CO-, CH2=CW 2 -(O) k3 -、CW 1 =CH-CO-(O) k3 -、CW 1 =CH-CO-NH-, CH2=CW 1 -CO-NH-, CH3-CH=CH-O-, (CH2=CH)2CH-OCO-, (CH2=CH-CH2)2CH-OCO-, (CH2=CH)2CH-O-, (CH2=CH-CH2)2N-, (CH2=CH-CH2)2N-CO-, HO-CW 2 W 3 -、HS-CW 2 W 3 -、HW 2 N-、HO-CW 2 W 3 -NH-, CH2=CW 1 -CO-NH-, CH2=CH-(COO) k1 -Phe-(O) k2 -、CH2=CH-(CO) k1 -Phe-(O) k2 -, Phe-CH=CH-, HOOC-, OCN- and W 4 W 5 W 6 Si-, where W 1 represents H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH3, W 2 and W 3 each independently of one another represents H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W 4 , W 5 and W 6 Each independently represents Cl, an oxaalkyl group or an oxacarbonylalkyl group having 1 to 5 C atoms, W 7 and W8 Each independently represents H, Cl or an alkyl group having 1 to 5 C atoms, Phe represents 1,4-phenylene which is optionally substituted by one or more substituents L different from P-Sp- as defined above for formula M, k1, k2 and k3 each independently represent 0 or 1, k3 preferably represents 1, and k4 represents an integer from 1 to 10.

[0491] Very preferably the group P is selected from CH2=CW 1 -CO-O-, CH2=CW 1 -CO-, CH2=CW 2 -O-, CH=CW 2 -、CW 1 =CH-CO-(O) k3 -、CW 1 =CH-CO-NH-, CH2=CW 1 -CO-NH-, (CH2=CH)2CH-OCO-, (CH2=CH-CH2)2CH-OCO-, (CH2=CH)2CH-O-, (CH2=CH-CH2)2N-, (CH2=CH-CH2)2N-CO-, CH2=CW 1 -CO-NH-, CH2=CH-(COO) k1 -Phe-(O) k2 -、CH2=CH-(CO) k1 -Phe-(O) k2 -, Phe-CH=CH- and W 4 W 5 W 6 Si-, where W 1 represents H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH3, W 2 and W 3 each independently of one another represents H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W 4 , W 5 and W 6 Each independently represents Cl, an oxaalkyl group or an oxacarbonylalkyl group having 1 to 5 C atoms, W 7 and W 8 Each independently represents H, Cl or an alkyl group having 1 to 5 C atoms, Phe represents 1,4-phenylene, k1, k2 and k3 each independently represent 0 or 1, k3 preferably represents 1, and k4 represents an integer of 1 to 10.

[0492] Very particularly preferred groups P are selected from the group consisting of CH2=CW1 -CO-O-, in particular CH2=CH-CO-O-, CH2=C(CH3)-CO-O- and CH2=CF-CO-O-, as well as CH2=CH-O-, (CH2=CH)2CH-O-CO-, (CH2=CH)2CH-O-,

[0493] Further preferred polymerizable groups P are selected from vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxy, most preferably from acrylate and methacrylate.

[0494] If Sp is different from a single bond, it preferably has the formula Sp"-X", so that the corresponding substituent P-Sp- conforms to the formula P-Sp"-X"-, where

[0495] Sp" denotes an alkylene radical 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 CH2 groups may each be independently of one another substituted by -O-, -S-, -NH-, -N(R 0 )-、-Si(R 0 R 00 )-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -S-CO-, -CO-S-, -N(R 00 )-CO-O-、-O-CO-N(R 0 )-、-N(R 0 )-CO-N(R 00 )-, -CH=CH- or -C≡C- in such a way that the O and / or S atoms are not directly connected to each other,

[0496] X" means -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CO-N(R 0 )-、-N(R 0 )-CO-、-N(R 0 )-CO-N(R 00 )-, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=N-, -N=CH-, -N=N-, -CH=CR 0 -、-CY 2 =CY 3 -, -C≡C-, -CH=CH-CO-O-, -O-CO-CH=CH- or a single bond,

[0497] R 0 and R 00 each independently of one another represents H or an alkyl group having 1 to 20 C atoms, and

[0498] Y 2 and Y 3 Each independently represents H, F, Cl or CN.

[0499] X" is preferably -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR 0 -、-NR 0 -CO-、-NR 0 -CO-NR 00 - or single key.

[0500] Typical spacer groups Sp and -Sp"-X"- are, for example, -(CH2) p1 -、-(CH2CH2O) q1 -CH2CH2-, -CH2CH2-S-CH2CH2-, -CH2CH2-NH-CH2CH2- or -(SiR 0 R 00 -O) p1 -, wherein p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R 0 and R 00 has the meaning indicated above in formula M.

[0501] Particularly preferred groups Sp and -Sp"-X"- are -(CH2) p1 -、-(CH2) p1 -O-, -(CH2) p1 -O-CO-, -(CH2) p1 -CO-O-, -(CH2) p1 -O-CO-O-, wherein p1 and q1 have the meanings indicated above.

[0502] Particularly preferred radicals Sp" are in each case linear ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methyl-iminoethylene, 1-methylalkylene, vinylene, propenylene and butenylene.

[0503] For the production of PSA displays, the polymerisable compounds contained in the LC medium are polymerised or crosslinked (if one compound contains two or more polymerisable groups) - by polymerisation in situ in the LC medium between the substrates of the LC display, optionally while applying a voltage to the electrodes.

[0504] The structure of the PSA display according to the invention corresponds to the usual geometries of PSA displays, such as those described in the prior art cited at the outset. Geometries without protrusions are preferred, in particular those geometries in which, in addition, the electrode on the color filter side is not structured and only the electrode on the TFT side has slots. Particularly suitable and preferred electrode structures for PS-VA displays are described, for example, in US 2006 / 0066793 A1.

[0505] The combination of the compounds of the preferred embodiments mentioned above with the above-described polymerized compounds leads to low threshold voltages, low rotational viscosities and very good low-temperature stability in the LC media according to the invention, together with constantly high clearing points and high VHR values.

[0506] The use of LC media containing polymerizable compounds enables particularly low pretilt angles to be established rapidly in PSA displays. In particular, the LC media exhibit significantly shortened response times, in particular grey-to-grey response times, in PSA displays compared with the media of the prior art.

[0507] Preference is generally given to LC media having a nematic LC phase and preferably no chiral liquid crystal phase.

[0508] The invention also relates to the use of an LC medium according to the invention as described above and below for electro-optical purposes, in particular for shutter glasses, for 3D applications, in TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, XB-FFS, PS-FFS, positive VA and positive PS-VA displays, and to an electro-optical display, in particular an electro-optical display of the aforementioned type, in particular a TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, XB-FFS, PS-FFS, positive VA (vertically aligned) or positive PS-VA display, containing an LC medium according to the invention as described above and below.

[0509] The invention also relates to an electro-optical display, such as an STN or matrix LC (MLC) display, having two plane-parallel outer plates which together with a frame form a liquid crystal cell, an integrated non-linear element for switching individual pixels on the outer plates, and a nematic LC medium with positive dielectric anisotropy and high specific resistance in the liquid crystal cell, wherein the nematic LC medium is an LC medium according to the invention as described above and below.

[0510] The LC media according to the invention enable a significant broadening of the usable parameter range. The achievable combination of clearing point, viscosity at low temperatures, thermal and UV stability and high optical anisotropy is far superior to previous materials from the prior art.

[0511] In particular, the combination of compounds of formula G with compounds of formulae LP1 and LP2 and optionally with compounds selected from formulae II to XXXII or subformulae thereof leads to compounds exhibiting moderately positive dielectric anisotropy and simultaneously increased dielectric constant ε perpendicular to the longitudinal axis of the LC molecules. ⊥ , while maintaining a low rotational viscosity and a low value of the ratio γ1 / K1 of the LC medium. This enables energy-saving LC displays, especially those in FFS, HB-FFS, XB-FFS and IPS mode, to be obtained with high brightness and transmittance and low response times.

[0512] The LC media according to the invention are suitable for mobile applications and TFT applications, such as mobile phones and PDAs. Furthermore, the LC media according to the invention are particularly suitable for use in FFS, HB-FFS, XB-FFS and IPS displays based on dielectrically positive liquid crystals.

[0513] The LC media according to the invention can achieve a rotational viscosity γ1 of ≤ 120 mPa·s, particularly preferably ≤ 100 mPa·s, while maintaining a nematic phase down to -20° C., preferably down to -30° C., particularly preferably down to -40° C. and maintaining a clearing point of ≥ 75° C., preferably ≥ 80° C., so that excellent MLC displays with fast response times can be obtained. The rotational viscosity is measured at 20° C.

[0514] The dielectric anisotropy Δ∈ of the LC media according to the invention at 20° C. and 1 kHz is preferably ≧+1.5, very preferably from +3 to +18, most preferably from +5 to +15.

[0515] The birefringence Δn of the LC media according to the invention at 20° C. is preferably from 0.08 to 0.2, very preferably from 0.09 to 0.15.

[0516] The rotational viscosity γ1 of the LC media according to the invention is preferably ≤120 mPa.s, more preferably ≤110 mPa.s and very preferably ≤90 mPa.s.

[0517] The ratio γ1 / K1 of the LC media according to the invention, wherein γ1 is the rotational viscosity and K1 is the elastic constant of the splay deformation, is preferably ≤7 mPa.s / pN, very preferably ≤6 mPa.s / pN and most preferably ≤5.5 mPa.s / pN.

[0518] The average elastic constant of the LC medium according to the invention is K av Preferably at least 14.0 pN, very preferably at least 15.0 pN, most preferably at least 16.0 pN. av It can be calculated according to the following formula: K av =(K1+K2+K3) / 3≈(K1+1 / 2*K1+K3) / 3.

[0519] The nematic phase range of the LC media according to the invention preferably has a width of at least 90° C., more preferably at least 100° C. and in particular at least 110° C. This range preferably extends at least from -25° C. to +90° C.

[0520] It goes without saying that by suitable selection of the components of the LC media according to the invention it is also possible to achieve higher clearing points (for example above 100° C.) at higher threshold voltages or lower clearing points at lower threshold voltages while maintaining the other advantageous properties. At correspondingly only slightly increased viscosities it is likewise possible to obtain LC media with higher Δε and thus lower thresholds. MLC displays according to the invention are preferably operated in the first Gooch and Tarry transmittance minimum [CH Gooch and HATarry, Electron. Lett. 10, 2-4, 1974; CH Gooch and HATarry, Appl. Phys., Vol. 8, 1575-1584, 1975], wherein, in addition to particularly advantageous electro-optical properties such as high steepness of characteristic lines and low angular dependence of the contrast (German Patent 30 22 818), a lower dielectric anisotropy is sufficient at the same threshold voltage as in similar displays in the second minimum. Compared to the case of LC media comprising cyano compounds, significantly higher specific resistance values ​​can be achieved with the LC media according to the invention in the first minimum. By suitable selection of the individual components and their weight proportions, the person skilled in the art is able to set the birefringence necessary for a predefined layer thickness for an MLC display using simple conventional methods.

[0521] Measurement of voltage holding ratio (HR) [S. Matsumoto et al., Liquid Crystals] 5, 1320 (1989); K. Niwa et al., Proc. SID Conference, San Francisco, June 1984, p. 304 (1984); G. Weber et al., Liquid Crystals [Liquid Crystals] 5 ,1381(1989)] have shown that Cyanophenylcyclohexane or Compared to similar LC media containing esters of the formulae ST-1, ST-2, RV, IA and IB, the LC media according to the invention comprising compounds of the formulae ST-1, ST-2, RV, IA and IB show a significantly smaller decrease in HR upon exposure to UV light.

[0522] The light and UV stability of the LC media according to the invention are significantly better, ie they show a significantly smaller decrease in HR on exposure to light, heat or UV light.

[0523] The construction of the MLC display according to the invention, constructed from polarizers, electrode substrates and surface-treated electrodes, corresponds to the customary design of displays of this type. The term "customary design" is to be understood in a broad sense and also encompasses all derivatives and variants of MLC displays, in particular matrix display elements based on poly-Si TFTs or MIMs.

[0524] However, a significant difference between the displays according to the invention and hitherto conventional displays based on twisted nematic liquid crystal cells lies in the choice of the LC parameters in the LC layer.

[0525] The LC media which can be used according to the invention are prepared in a manner conventional per se, for example by mixing one or more compounds according to claim 1 with one or more compounds of the formulae II to XXXII or with other LC compounds and / or additives. In general, the required amount of the component used in smaller amounts is dissolved in the component constituting the main constituent, advantageously at elevated temperature. It is also possible to mix solutions of the components in organic solvents, for example in acetone, chloroform or methanol, and to remove the solvent again after thorough mixing, for example by distillation.

[0526] The LC medium may also contain further additives known to the person skilled in the art and described in the literature, for example polymerization initiators, inhibitors, surface-active substances, light stabilizers, antioxidants, for example BHT, TEMPOL, microparticles, free radical scavengers, nanoparticles, etc. For example, 0 to 15% of pleochroic dyes or chiral dopants or initiators may be added, such as 651 or 907. Suitable stabilizers and dopants are mentioned below in Tables F and G. In a preferred embodiment, the LC medium comprises one or more stabilizers selected from Table G. Preferably, the stabilizers as described above or as listed in Table G, such as those of the formulae ST and H, are present in the LC medium in a proportion of 10 to 2000 ppm, very preferably 30 to 1000 ppm.

[0527] Furthermore, it is also possible to add, for example, 0 to 15% by weight of pleochroic dyes to the LC medium, and also nanoparticles, conductive salts, preferably ethyldimethyldodecylammonium 4-hexyloxybenzoate, tetrabutylammonium tetraphenylborate, or complex salts of crown ethers (see, for example, Haller et al., Mol. Cryst. Liq. Cryst. [Molecular Crystals and Liquid Crystals]). 24 , 249-258 (1973)) to improve the conductivity, or to change the dielectric anisotropy, viscosity and / or the orientation of the nematic phase. This type of material is described, for example, in DE-A 22 09 127, 22 40 864, 23 21 632, 23 38 281, 2450 088, 26 37 430 and 2853 728.

[0528] For the present invention and in the following examples, the structures of the LC compounds are indicated with the aid of acronyms, which are converted into chemical formulae according to the following tables A to C. All substituents CmH2m+1, CnH2n+1 and ClH2l+1 or CmH2m-1, CnH2n-1 and ClH2l-1 are straight-chain alkyl or alkenyl groups having n, m and 1 C atoms, respectively, in each case. Preferably, n, m and 1 are, independently of one another, 1, 2, 3, 4, 5, 6 or 7. Table A shows the codes for the ring elements of the core of the compounds, Table B lists the bridging units and Table C lists the meaning of the symbols for the left-hand and right-hand end groups of the molecules. The acronyms consist of the code for the ring element with the optional linking group, followed by the first hyphen and the code for the left-hand end group, and the second hyphen and the code for the right-hand end group. Table D shows exemplary structures of the compounds and their respective abbreviations.

[0529] Table A: Ring Elements

[0530]

[0531]

[0532]

[0533] Table B: Bridging Units

[0534]

[0535]

[0536] Table C: End Groups

[0537]

[0538]

[0539] where n and m are each integers, and the three dots "..." are placeholders for other abbreviations from the table.

[0540] The following abbreviations are used:

[0541] (n, m, k and l are each independently an integer from 1 to 12, preferably from 1 to 6, k and l may also be 0, preferably 0 to 4, more preferably 0 or 2, most preferably 2, n is preferably 1, 2, 3, 4 or 5, in the combination "-nO-", it is preferably 1, 2, 3 or 4, preferably 2 or 4, m is preferably 1, 2, 3, 4 or 5, in the combination "-Om", it is preferably 1, 2, 3 or 4, more preferably 2 or 4. The combination "-lVm" is preferably "2V1".)

[0542] Preferred components of the LC media are shown in Tables D and E.

[0543] Table D

[0544]

[0545]

[0546]

[0547]

[0548] Table E

[0549] In the following formulae, n and m each independently represent 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, in particular 2, 3, 5 and also 0, 4, 6.

[0550]

[0551]

[0552]

[0553]

[0554]

[0555]

[0556]

[0557]

[0558]

[0559]

[0560]

[0561]

[0562]

[0563] Particular preference is given to LC media which, in addition to the compounds of the formulae G, LP1 and LP2, comprise at least one, two, three, four or more compounds from Table E.

[0564] Table F

[0565] Table F indicates possible dopants which are typically added to the LC media according to the invention. The LC media preferably comprise 0 to 10% by weight, in particular 0.01 to 5% by weight, particularly preferably 0.01 to 3% by weight, of dopant.

[0566]

[0567]

[0568] Table G

[0569] Mentioned below are stabilizers which can additionally be added to the LC media according to the invention, for example in amounts of 0 to 10% by weight.

[0570]

[0571]

[0572]

[0573]

[0574] Table H

[0575] Table H shows exemplary reactive mesogenic compounds (RM) which can be used in the LC media according to the present invention.

[0576]

[0577]

[0578]

[0579]

[0580]

[0581]

[0582]

[0583]

[0584]

[0585]

[0586]

[0587]

[0588]

[0589]

[0590]

[0591]

[0592]

[0593]

[0594]

[0595]

[0596]

[0597] The LC media according to the present invention may optionally comprise one or more polymerisable compounds, preferably selected from the group consisting of formulae RM-1 to RM-184. Among them, compounds RM-1, RM-4, RM-8, RM-17, RM-19, RM-35, RM-37, RM-39, RM-40, RM-41, RM-48, RM-52, RM-54, RM-57, RM-58, RM-64, RM-74, RM-76, RM-88, RM-91, RM-102, RM-103, RM-1 09. RM-116, RM-117, RM-120, RM-121, RM-122, RM-139, RM-140, RM-142, RM-143, RM-14 5. RM-146, RM-147, RM-149, RM-156 to RM-163, RM-169, RM-170 and RM-171 to RM-184 are particularly preferred.

[0598] Table I

[0599] Table 1 shows self-alignment additives for homeotropic alignment which can be used in LC media for SA-FFS, SA-HB-FFS and SA-XB-FFS displays according to the invention:

[0600]

[0601]

[0602]

[0603]

[0604]

[0605]

[0606]

[0607]

[0608]

[0609]

[0610]

[0611] In a preferred embodiment, the LC media, SA-VA and SA-FFS displays according to the invention comprise one or more SA additives selected from the formulae SA-1 to SA-49, preferably from the formulae SA-14 to SA-49, very preferably from the formulae SA-20 to SA-34 and SA-44 in combination with one or more RMs. DETAILED DESCRIPTION

[0612] The following examples are intended to illustrate the present invention rather than to limit the present invention.

[0613] In this context, percentage data refer to percentages by weight. All temperatures are given in ° C. mp = melting point, cl.p. = clearing point. In addition, C = crystalline, N = nematic, S = smectic, I = isotropic. The data between these symbols represent transition temperatures. In addition, the following symbols are used:

[0614] V0 Freedericks threshold voltage at 20°C, capacitive [V],

[0615] V 10 For the voltage [V] at 10% transmittance,

[0616] n e The extraordinary refractive index measured at 20°C and 589 nm,

[0617] n0 is the ordinary refractive index measured at 20°C and 589nm,

[0618] △ n Optical anisotropy measured at 20°C and 589 nm,

[0619] ε ⊥ The dielectric polarizability (or "dielectric constant") perpendicular to the longitudinal axis of the molecule at 20°C and 1 kHz,

[0620] ε||The dielectric polarizability (or "dielectric constant") parallel to the longitudinal axis of the molecule at 20°C and 1kHz,

[0621] Dielectric anisotropy of △ε at 20℃ and 1kHz,

[0622] cl.p.or

[0623] T(N,I) clearing point [℃],

[0624] νFlow viscosity measured at 20°C [mm 2 ·s -1 ],

[0625] γ1 Rotational viscosity measured at 20°C [mPa·s],

[0626] K1 elastic constant, "bending" deformation at 20°C [pN],

[0627] K2 elastic constant, "twist" deformation at 20°C [pN],

[0628] K3 elastic constant, "bending" deformation at 20°C [pN], and

[0629] VHR voltage holding rate ( v oltage h olding r atio).

[0630] Unless explicitly stated otherwise, all physical properties are measured according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals", state November 1997, Merck KGaA, Germany, and apply to a temperature of 20°C.

[0631] Example

[0632] Example M1 (comparative)

[0633] The nematic LC medium was prepared as follows:

[0634]

[0635] This LC mixture has a K of 14.85 pN. av and γ1 / K1 of 3.37 mPa·s / pN.

[0636] Mixture Example S1 (Stabilized with a Compound of Formula ST-1-3)

[0637] The nematic LC mixture according to the invention was formulated as follows:

[0638] Mixture M1 99.95% by weight Compound of formula ST-1-3 500ppm

[0639] Compared to the unstabilized mixture M1, the addition of 500 ppm of the compound of formula ST-1-3 significantly improved the VHR after UV exposure. 100 , without affecting the remaining physical properties of mixture M1.

[0640]

[0641] Example M2

[0642] The nematic LC medium was prepared as follows:

[0643]

[0644] This LC mixture has a K of 15.98 pN. av and γ1 / K1 of 3.21 mPa·s / pN.

[0645] Mixture Example S2 (stabilized with a compound of formula H-3-5)

[0646] The nematic LC mixture according to the invention was formulated as follows:

[0647] Mixture M2 99.995% by weight Compound of formula H-3-5 50ppm

[0648] Compared to the unstabilized mixture M2, the addition of 50 ppm of the compound of formula H-3-5 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of mixture M2.

[0649]

[0650] Example M3

[0651] The nematic LC medium was prepared as follows:

[0652]

[0653] This LC mixture has a K of 15.48 pN. av and γ1 / K1 of 3.25 mPa·s / pN.

[0654] Mixture Example S3 (Stabilized with a Compound of Formula H-3-3)

[0655] The nematic LC mixture according to the invention was formulated as follows:

[0656] Mixture M3 99.9% by weight Compound of formula H-3-3 1000ppm

[0657] Compared to the unstabilized mixture M3, the addition of 1000 ppm of the compound of formula H-3-3 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of mixture M3.

[0658]

[0659] Embodiment M4

[0660] The nematic LC medium was prepared as follows:

[0661]

[0662] This LC mixture has a K of 15.38 pN. av and γ1 / K1 of 3.25 mPa·s / pN.

[0663] Mixture Example S4 (Stabilized with a Compound of Formula H-3-1)

[0664] The nematic LC mixture according to the invention was formulated as follows:

[0665] Mixture M4 99.9% by weight Compound of formula H-3-1 1000ppm

[0666] Compared to the unstabilized mixture M4, the addition of 1000 ppm of the compound of formula H-3-1 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of mixture M4.

[0667]

[0668] Example M5

[0669] The nematic LC medium was prepared as follows:

[0670]

[0671] This LC mixture has a K of 15.50 pN. av and γ1 / K1 of 3.23 mPa·s / pN.

[0672] Mixture Example S5 (Stabilized with a Compound of Formula ST-2-3)

[0673] The nematic LC mixture according to the invention was formulated as follows:

[0674] Mixture M5 99.95% by weight Compound of formula ST-2-3 500ppm

[0675] Compared to the unstabilized mixture M5, the addition of 500 ppm of the compound of formula ST-2-3 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of mixture M5.

[0676]

[0677] Example M6

[0678] The nematic LC medium was prepared as follows:

[0679]

[0680]

[0681] This LC mixture has a K of 15.37 pN. av and γ1 / K1 of 3.45 mPa·s / pN.

[0682] Mixture Example S6 (stabilized with a compound of formula H-3-7)

[0683] The nematic LC mixture according to the invention was formulated as follows:

[0684] Mixture M6 99.9% by weight Compound of formula H-3-7 1000ppm

[0685] Compared to the unstabilized mixture M6, the addition of 1000 ppm of the compound of formula H-3-7 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of mixture M6.

[0686]

[0687] Embodiment M7

[0688] The nematic LC medium was prepared as follows:

[0689]

[0690]

[0691] Mixture Example S7 (stabilized with a compound of formula H-3-4)

[0692] The nematic LC mixture according to the invention was formulated as follows:

[0693] Mixture M7 99.995% by weight Compound of formula H-3-4 50ppm

[0694] Compared to the unstabilized mixture M7, the addition of 50 ppm of the compound of formula H-3-4 significantly improved the VHR after UV exposure. 100 , without affecting the remaining physical properties of mixture M7.

[0695]

[0696] Embodiment M8

[0697] The nematic LC medium was prepared as follows:

[0698]

[0699]

[0700] Mixture Example S8 (Stabilized with a Compound of Formula ST-1-2)

[0701] The nematic LC mixture according to the invention was formulated as follows:

[0702] Mixture M8 99.95% by weight Compound of formula ST-1-2 500ppm

[0703] Compared to the unstabilized mixture M8, the addition of 500 ppm of the compound of formula ST-1-2 significantly improved the VHR after UV exposure. 100, without affecting the other physical properties of mixture M8.

[0704]

[0705] Embodiment M9

[0706] The nematic LC medium was prepared as follows:

[0707]

[0708] Mixture Example S9 (Stabilized with a Compound of Formula ST-4-1)

[0709] The nematic LC mixture according to the invention was formulated as follows:

[0710] Mixture M9 99.95% by weight Compound of formula ST-4-1 500ppm

[0711] Compared to the unstabilized mixture M9, the addition of 500 ppm of the compound of formula ST-4-1 significantly improved the VHR after UV exposure. 100 , without affecting the remaining physical properties of mixture M9.

[0712]

[0713] Embodiment M10

[0714] The nematic LC medium was prepared as follows:

[0715]

[0716]

[0717] Mixture Example S10 (Stabilized with a Compound of Formula ST-2-8)

[0718] The nematic LC mixture according to the invention was formulated as follows:

[0719] Mixture M10 99.95% by weight Compound of formula ST-2-8 500ppm

[0720] Compared to the unstabilized mixture M10, the addition of 500 ppm of the compound of formula ST-2-8 significantly improved the VHR after UV exposure. 100 , without affecting the remaining physical properties of mixture M10.

[0721]

[0722] Embodiment M11

[0723] The nematic LC medium was prepared as follows:

[0724]

[0725] The K of the LC mixture av is 17.47 pN and γ1 / K1 is 3.96 mPa·s / pN.

[0726] Mixture Example S11 (Stabilized with a Compound of Formula ST-2-3)

[0727] The nematic LC mixture according to the invention was formulated as follows:

[0728] Mixture M11 99.96% by weight Compound of formula ST-2-3 400ppm

[0729] Compared to the unstabilized mixture M11, the addition of 400 ppm of the compound of formula ST-2-3 significantly improved the VHR after UV exposure. 100 , without affecting the remaining physical properties of mixture M11.

[0730] Example M12

[0731] The nematic LC medium was prepared as follows:

[0732]

[0733] The K of the LC mixture av is 18.02 pN and γ1 / K1 is 3.54 mPa·s / pN.

[0734] Mixture Example S12 (Stabilized with the Compound of Formula H-3-2)

[0735] The nematic LC mixture according to the invention was formulated as follows:

[0736] Mixture M12 99.995% by weight Compound of formula H-3-2 50ppm

[0737] Compared to the unstabilized mixture M12, the addition of 50 ppm of the compound of formula H-3-2 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of the mixture.

[0738]

[0739] Example M13

[0740] The nematic LC medium was prepared as follows:

[0741]

[0742] The K of the LC mixture av is 16.37 pN and γ1 / K1 is 3.25 mPa·s / pN.

[0743] Mixture Example S13 (Stabilized with a Compound of Formula H-3-4)

[0744] The nematic LC mixture according to the invention was formulated as follows:

[0745] Mixture M13 99.995% by weight Compound of formula H-3-4 50ppm

[0746] Compared to the unstabilized mixture M13, the addition of 50 ppm of the compound of formula H-3-4 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of the mixture.

[0747]

[0748] Embodiment M14

[0749] The nematic LC medium was prepared as follows:

[0750]

[0751] The K of the LC mixture av is 17.52 pN and γ1 / K1 is 3.78 mPa·s / pN.

[0752] Mixture Example S14 (Stabilized with a Compound of Formula H-3-6)

[0753] The nematic LC mixture according to the invention was formulated as follows:

[0754] Mixture M14 99.995% by weight Compound of formula H-3-6 50ppm

[0755] Compared to the unstabilized mixture M14, the addition of 50 ppm of the compound having the formula H-3-6 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of the mixture.

[0756]

[0757] Example M15

[0758] The nematic LC medium was prepared as follows:

[0759]

[0760] The K of the LC mixture av is 18.27 pN and γ1 / K1 is 3.60 mPa·s / pN.

[0761] Mixture Example S15 (Stabilized with a Compound of Formula H-3-8)

[0762] The nematic LC mixture according to the invention was formulated as follows:

[0763] Mixture M15 99.9% by weight Compound of formula H-3-8 1000ppm

[0764] Compared to the unstabilized mixture M15, the addition of 1000 ppm of the compound of formula H-3-8 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of the mixture.

[0765]

[0766] Example M16

[0767] The nematic LC medium was prepared as follows:

[0768]

[0769] The K of the LC mixture av is 17.55 pN and γ1 / K1 is 3.79 mPa·s / pN.

[0770] Mixture Example S16 (Stabilized with the Compound of Formula H-3-11)

[0771] The nematic LC mixture according to the invention was formulated as follows:

[0772] Mixture M16 99.995% by weight Compound of formula H-3-11 50ppm

[0773] Compared to the unstabilized mixture M16, the addition of 50 ppm of the compound having the formula H-3-11 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of the mixture.

[0774]

[0775] Example M17

[0776] The nematic LC medium was prepared as follows:

[0777]

[0778] The K of the LC mixture av is 11.90pN and γ1 / K1 is 4.86mPa·s / pN.

[0779] Mixture Example S17 (Stabilized with a Compound of Formula H-3-9)

[0780] The nematic LC mixture according to the invention was formulated as follows:

[0781] Mixture M17 99.995% by weight Compound of formula H-3-9 50ppm

[0782] Compared to the unstabilized mixture M17, the addition of 50 ppm of the compound having the formula H-3-9 significantly improved the VHR after UV exposure. 100, without affecting the other physical properties of the mixture.

[0783]

[0784] Example M18

[0785] The nematic LC medium was prepared as follows:

[0786]

[0787] The K of the LC mixture av is 17.73 pN and γ1 / K1 is 3.76 mPa·s / pN.

[0788] Mixture Example S18 (Stabilized with the Compound of Formula H-3-10)

[0789] The nematic LC mixture according to the invention was formulated as follows:

[0790] Mixture M18 99.995% by weight Compound of formula H-3-10 50ppm

[0791] Compared to the unstabilized mixture M18, the addition of 50 ppm of the compound having the formula H-3-10 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of the mixture.

[0792]

[0793] Example M19

[0794] The nematic LC medium was prepared as follows:

[0795]

[0796] The K of the LC mixture av is 18.07 pN and γ1 / K1 is 3.99 mPa·s / pN.

[0797] Mixture Example S19 (Stabilized with the Compound of Formula H-3-12)

[0798] The nematic LC mixture according to the invention was formulated as follows:

[0799] Mixture M19 99.995% by weight Compound of formula H-3-12 50ppm

[0800] Compared to the unstabilized mixture M19, the addition of 50 ppm of the compound having the formula H-3-12 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of the mixture.

[0801]

[0802] Embodiment M20

[0803] The nematic LC medium was prepared as follows:

[0804]

[0805] The K of the LC mixture av is 15.65 pN and γ1 / K1 is 7.24 mPa·s / pN.

[0806] Mixture Example S20 (Stabilized with Compound of Formula H-3-14)

[0807] The nematic LC mixture according to the invention was formulated as follows:

[0808] Mixture M20 99.995% by weight Compound of formula H-3-14 50ppm

[0809] Compared to the unstabilized mixture M20, the addition of 50 ppm of the compound having the formula H-3-14 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of the mixture.

[0810]

[0811] Example M21

[0812] The nematic LC medium was prepared as follows:

[0813]

[0814] The K of the LC mixture av is 18.05 pN and γ1 / K1 is 4.98 mPa·s / pN.

[0815] Mixture Example S21 (Stabilized with a Compound of Formula H-3-13)

[0816] The nematic LC mixture according to the invention was formulated as follows:

[0817] Mixture M21 99.995% by weight Compound of formula H-3-13 50ppm

[0818] Compared to the unstabilized mixture M21, the addition of 50 ppm of the compound having the formula H-3-13 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of the mixture.

[0819]

[0820] Example M22

[0821] The nematic LC medium was prepared as follows:

[0822]

[0823] The K of the LC mixture av is 17.30 pN and γ1 / K1 is 4.90 mPa·s / pN.

[0824] Mixture Example S22 (Stabilized with a Compound of Formula H-3-17)

[0825] The nematic LC mixture according to the invention was formulated as follows:

[0826] Mixture M22 99.995% by weight Compound of formula H-3-17 50ppm

[0827] Compared to the unstabilized mixture M22, the addition of 50 ppm of the compound having the formula H-3-17 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of the mixture.

[0828]

[0829] Example M23

[0830] The nematic LC medium was prepared as follows:

[0831]

[0832] The K of the LC mixture av is 17.08 pN and γ1 / K1 is 3.73 mPa·s / pN.

[0833] Mixture Example S23 (Stabilized with Compounds of Formula H-3-15 and ST-1-3)

[0834] The nematic LC mixture according to the invention was formulated as follows:

[0835] Mixture M23 99.955% by weight Compound of formula H-3-15 50ppm Compound of formula ST-1-3 400ppm

[0836] Compared to the unstabilized mixture M23, the addition of compounds having formula H-3-15 and ST-1-3 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of the mixture.

[0837]

[0838] Example M24

[0839] The nematic LC medium was prepared as follows:

[0840]

[0841] The K of the LC mixture avis 18.25 pN and γ1 / K1 is 3.95 mPa·s / pN.

[0842] Mixture Example S24 (Stabilized with a Compound of Formula H-3-16)

[0843] The nematic LC mixture according to the invention was formulated as follows:

[0844] Mixture M24 99.99% by weight Compound of formula H-3-16 100ppm

[0845] Compared to the unstabilized mixture M24, the addition of 100 ppm of the compound having the formula H-3-16 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of the mixture.

[0846]

[0847] Example M25

[0848] The nematic LC medium was prepared as follows:

[0849]

[0850] The K of the LC mixture av is 18.13 pN and γ1 / K1 is 3.96 mPa·s / pN.

[0851] Mixture Example S25 (Stabilized with Compounds of Formula H-3-1 and ST-2-3)

[0852] The nematic LC mixture according to the invention was formulated as follows:

[0853] Mixture M25 99.88% by weight Compound of formula H-3-1 800ppm Compound of formula ST-2-3 400ppm

[0854] Compared to the unstabilized mixture M25, the addition of compounds of formula H-3-1 and ST-2-3 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of the mixture.

[0855] Example M26

[0856] The nematic LC medium was prepared as follows:

[0857]

[0858] The K of the LC mixture av is 16.60 pN and γ1 / K1 is 5.21 mPa·s / pN.

[0859] Mixture Example S26 (Stabilized with Compounds of Formula H-3-2 and ST-1-3)

[0860] The nematic LC mixture according to the invention was formulated as follows:

[0861] Mixture M26 99.97% by weight Compound of formula H-3-2 100ppm Compound of formula ST-1-3 200ppm

[0862] Compared to the unstabilized mixture M26, the addition of compounds of formula H-3-2 and ST-1-3 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of the mixture.

[0863] Example M27

[0864] The nematic LC medium was prepared as follows:

[0865]

[0866] The K of the LC mixture av is 17.70 pN and γ1 / K1 is 4.44 mPa·s / pN.

[0867] Mixture Example S27 (Stabilized with the Compound of Formula H-3-18)

[0868] The nematic LC mixture according to the invention was formulated as follows:

[0869] Mixture M27 99.995% by weight Compound of formula H-3-18 50ppm

[0870] Compared to the unstabilized mixture M27, the addition of 50 ppm of the compound having the formula H-3-18 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of the mixture.

[0871]

[0872] Embodiment M28

[0873] The nematic LC medium was prepared as follows:

[0874]

[0875] The K of the LC mixture av is 17.85 pN and γ1 / K1 is 4.55 mPa·s / pN.

[0876] Mixture Example S28 (Stabilized with Compound of Formula H-3-19)

[0877] The nematic LC mixture according to the invention was formulated as follows:

[0878] Mixture M28 99.995% by weight Compound of formula H-3-19 50ppm

[0879] Compared to the unstabilized mixture M28, the addition of 50 ppm of the compound having the formula H-3-19 significantly improved the VHR after UV exposure.100 , without affecting the other physical properties of the mixture.

[0880]

[0881] Example M29

[0882] The nematic LC medium was prepared as follows:

[0883]

[0884] The K of the LC mixture av is 12.37 pN and γ1 / K1 is 3.06 mPa·s / pN.

[0885] Mixture Example S29 (Stabilized with a Compound of Formula ST-1-3)

[0886] The nematic LC mixture according to the invention was formulated as follows:

[0887] Mixture M29 99.97% by weight Compound of formula ST-1-3 300ppm

[0888] Compared to the unstabilized mixture M29, the addition of 300 ppm of the compound of formula ST-1-3 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of the mixture.

[0889] Embodiment M30

[0890] The nematic LC medium was prepared as follows:

[0891]

[0892] The K of the LC mixture av is 14.52 pN and γ1 / K1 is 3.62 mPa·s / pN.

[0893] Mixture Example S30 (Stabilized with a Compound of Formula ST-1-3)

[0894] The nematic LC mixture according to the invention was formulated as follows:

[0895] Mixture M30 99.97% by weight Compound of formula ST-1-3 300ppm

[0896] Compared to the unstabilized mixture M30, the addition of 300 ppm of the compound of formula ST-1-3 significantly improved the VHR after UV exposure. 100 , without affecting the other physical properties of the mixture.

Claims

1. A liquid crystal medium, characterized in that It contains one or more compounds of formula G one or more compounds of formula LP1, and optional One or more compounds of formula LP2 The substituents have the following meanings: R1 and R2 each independently represent an H atom, a halogen atom, -CN, -SCN, -NCS, an alkyl or alkoxy group having 1 to 12 C atoms, or an alkenyl or alkenyloxy group having 2 to 12 C atoms, wherein one or more non-adjacent CH2 groups are optionally replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- is substituted in such a way that the O atoms are not directly attached to one another and in which one or more H atoms may be replaced by a halogen atom or a cycloalkyl or cycloalkoxy group having 3 to 12 C atoms in which one or more H atoms may be replaced by a halogen atom; Y1 represents an H atom, an alkyl group having 1 to 3 C atoms or an alkenyl group having 2 to 3 C atoms, wherein one or more non-adjacent CH2 groups are optionally substituted by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- in such a way that the O atoms are not directly connected to one another; R0 and R3 represent an alkyl or alkoxy group having 1 to 12 C atoms or an alkenyl or alkenyloxy group having 2 to 12 C atoms, wherein one or more non-adjacent CH2 groups are optionally replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- is substituted in such a way that the O atoms are not directly attached to one another and in which one or more H atoms may be replaced by a cycloalkyl or cycloalkoxy group having 3 to 12 C atoms; L1 and L2 each independently represent H, F or Cl; Y0 each independently represents H or CH3; X0 represents a halogen atom, CN, SCN, NCS or an alkyl or alkoxy group having 1 to 6 C atoms or an alkenyl or alkenyloxy group having 2 to 6 C atoms, wherein one or more H atoms are replaced by F atoms, A1 and A2 each independently of one another denote phenylene-1,4-diyl, wherein, in addition, one or two CH groups may be replaced by N and one or more H atoms may be replaced by halogen, CN, CH3, CHF2, CH2F, CF3, OCH3, OCHF2 or OCF3; cyclohexane-1,4-diyl, wherein, in addition, one or two non-adjacent CH2 groups may be replaced independently of one another by O and / or S and one or more H atoms may be replaced by F; cyclohexene-1,4-diyl, bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, tetrahydropyran-2,5-diyl or 1,3-dioxane-2,5-diyl; Z1 and Z2 each independently represent -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CO-O-, -O-CO-, -C2H4-, -C2F4-, -CF2CH2-, -CH2CF2-, -CFHCFH-, -CFHCH2-, -CH2CFH-, -CF2CFH-, -CFHCF2-, -CH=CH-, -CF=CH-, -CH=CF-, -CF=CF-, -C≡C- or a single bond; k and l each independently represent 0, 1, 2 or 3.

2. The medium according to claim 1, characterized in that In formula G R1 and R2 are as defined in claim 1; A1 represents phenylene-1,4-diyl, cyclohexane-1,4-diyl, cyclohexene-1,4-diyl, tetrahydropyran-2,5-diyl or 1,3-dioxane-2,5-diyl; Z1 represents a single bond; Y1 represents H or CH3; k represents 1; and l means 0.

3. The medium according to claim 1 or 2, characterized in that The compound of formula G is selected from the following compounds: wherein R1, R2 and Y1 are as defined in claim 1.

4. Liquid-crystalline medium according to one or more of claims 1 to 3, characterized in that The one or more compounds of formula LP1 and LP2 are described by formula LP1-1 and LP2-1: in R0 and R3 represent an alkyl or alkoxy group having 1 to 6 C atoms or an alkenyl group having 2 to 6 C atoms, wherein one or more CH2 groups are optionally replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- are substituted in such a way that the O atoms are not directly attached to each other; and X0 represents an F atom or an alkyl or alkoxy group having 1 to 3 C atoms or an alkenyl or alkenyloxy group having 2 or 3 C atoms, wherein one or more H atoms are replaced by F atoms.

5. A medium according to one or more of claims 1 to 4, characterised in that It contains one or more compounds selected from the following formulae: The substituents have the following meanings: R0 has one of the meanings given to R1, R3 and R4 in claim 1; X0 has one of the meanings given to X0 in claim 4; L1 to L6 each independently represent H, F or Cl; Y0 each independently represents H or CH3.

6. The medium according to claim 5, wherein the one or more compounds of formula II are selected from the following subformulae: wherein R0 and X0 have the meanings given in formula II.

7. The medium according to claim 5, wherein the one or more compounds of formula III are selected from the following subformulae: wherein R0 and X0 have the meanings given in formula III.

8. A medium according to one or more of claims 1 to 7, characterised in that It further comprises one or more compounds selected from the following formulae: Wherein R0, X0, L1, L2 and Y0 have the meanings given in claim 5; L3 and L4 each independently have the meaning given for L1; Z0 represents -C2H4-, -(CH2)4-, -CH=CH-, -CF=CF-, -C2F4-, -CH2CF2-, -CF2CH2-, -CH2O-, -OCH2-, -COO-, -CF2O- or -OCF2-, and in formulas V and VI also represents a single bond; and s represents 0 or 1.

9. A medium according to one or more of claims 1 to 8, characterized in that It contains one or more compounds selected from the following formulae: The substituents have the following meanings: "alkyl" and "alkyl*" each independently represent an alkyl group having 1 to 6 C atoms; "Alkenyl" and "alkenyl*" each independently of one another represent alkenyl having 2 to 6 C atoms.

10. The medium according to one or more of claims 1 to 9, characterized in that It contains one or more compounds selected from the following formulae: in R1 and R2 each independently represent an alkyl, alkoxy, oxaalkyl or fluoroalkyl group each having 1 to 6 C atoms, or an alkenyl group having 2 to 6 C atoms; and L1 has the meaning indicated in claim 4.

11. The medium according to one or more of claims 1 to 10, characterized in that It comprises one or more compounds selected from the following formula Wherein R0, X0, Y0 and L1-4 each independently have one of the meanings indicated in claim 5.

12. The medium according to one or more of claims 1 to 11, characterized in that It comprises one or more compounds selected from the following formula in and R1 and X0 have the meanings indicated for R0 and X0 in claim 5, respectively.

13. The medium according to one or more of claims 1 to 12, characterized in that It comprises compounds of formula G, LP1 and LP2 and one or more compounds selected from formula Z1, Z2, Z3, Z4, Z5, II, III, IV, V, VI, VII, VIII, XIV, XVI, XX, XXIII, XXIX, XVIIa, XVIIb, XVIIc, XXXII and XXXIV.

14. A medium according to one or more of claims 1 to 13, characterized in that It further comprises one or more additives.

15. Process for preparing a liquid-crystalline medium according to one or more of claims 1 to 14, characterized in that One or more compounds of formula G and one or more compounds of formulae LP1 and LP2 are mixed with one or more mesogenic compounds and optionally one or more polymerizable compounds and / or one or more additives.

16. Use of a liquid-crystalline medium according to one or more of claims 1 to 14 for electro-optical purposes.

17. An electro-optical liquid crystal display or an AR / VR headset comprising a liquid crystal medium according to one or more of claims 1 to 14.

18. The electro-optical liquid crystal display according to claim 17, characterized in that It is a TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, XB-FFS, PS-HB-FFS, PS-XB-FFS, SA-HB-FFS, SA-XB-FS, polymer-stabilized SA-HB-FFS, polymer-stabilized SA-XB-FFS, positive VA or positive PS-VA display.

19. The electro-optical liquid crystal display according to claim 17, characterized in that It is a FFS, HB-FFS, XB-FFS, PS-HB-FFS, PS-XB-FFS, IPS or PS-IPS display.

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