Liquid crystal medium

Abstract

The present invention relates to liquid crystal (LC) media and liquid crystal displays (LCDs) containing these media, in particular to displays addressed by an active matrix and in particular to LC energy saving 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

[0001] The present invention relates to liquid crystal (LC) media and liquid crystal displays (LCDs) containing these media, in particular to displays addressed by an active matrix and, in particular, to energy-efficient 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 positive dielectric anisotropy.

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

[0003] In addition to these modes, there are also electro-optic modes, which utilize 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, and is therefore referred to as an in-plane switching (IPS) display. The principle of operation of such a display is described, for example, by R. A. Soref in Journal of Applied Physics, Vol. 45, No. 12, pp. 5466-5468 (1974).

[0004] IPS displays contain an LC layer between two planarly oriented substrates. Two electrodes are provided on only one of the two substrates and preferably have an interdigitated, comb-shaped structure. When a voltage is applied to the electrodes, an electric field with a significant component parallel to the LC layer is generated between them. This results in a realignment of the LC molecules in the layer plane.

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

[0006] LC 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, inter alia, SH Jung et al., Jpn. J. Appl. Phys., Vol. 43, No. 3, 2004, 1028), which comprise two electrodes on the same substrate, one of which is structured in a comb-like manner and the other unstructured. This results in a strong so-called "fringe field," i.e., a strong electric field close to the electrode edges and an electric field with both a strong vertical component and a strong horizontal component throughout the liquid crystal cell. FFS displays have a low viewing angle dependence of the contrast. FFS displays generally comprise an LC medium with positive dielectric anisotropy and an alignment layer, generally of polyimide, which provides a planar alignment for the molecules of the LC medium.

[0008] LC displays in the IPS and FFS electro-optical modes are particularly suitable for modern desktop monitors, televisions, and multimedia applications. The LC media according to the invention are preferably used in these types of displays. Generally, positive dielectric LC media with relatively low dielectric anisotropy values ​​are used in FFS displays, but in some cases, LC media with dielectric anisotropy values ​​of only about 3 or even less are also used in IPS displays.

[0009] Further improvements are achieved through the HB-FFS mode. Compared to conventional FFS technology, one of the unique features of the HB-FFS mode is its ability to allow higher transmittance, which allows the panel to operate with less energy consumption.

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

[0011] LC compositions suitable for LCDs, and in particular for FFS and IPS displays, are known from 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, DE 195 28 107, WO 96 / 23 851, and WO 96 / 28 521. However, these compositions have certain disadvantages. Among other drawbacks, most of them result in undesirably long addressing times, have insufficient resistivity values, and / or require excessively high operating voltages. Improvements are necessary both in terms of operating properties and shelf life.

[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 typically addressed by integrated non-linear active elements (e.g., thin film transistors (TFTs)), while in the case of passive matrix displays, the individual pixels are typically addressed by multiplexing methods known in the art.

[0013] The display according to the invention is preferably addressed by an active matrix, preferably by a matrix of TFTs. However, the liquid crystals according to the invention can also be advantageously used in displays having other known addressing means.

[0014] Typical applications of in-plane switching (IPS) and fringe field switching (FFS) technologies are monitors, notebook computers, TVs, mobile phones, tablet PCs, etc.

[0015] Both IPS and FFS technologies have certain advantages over other LCD technologies, such as vertical alignment (VA) technology, such as wide viewing angle dependence of contrast ratio.

[0016] The provision of alternative LC media and their use in displays with high transmittance, a good black state and high contrast are major challenges for modern FFS and IPS applications. In addition, modern applications also require good low-temperature stability and fast addressing times.

[0017] So far, it has not been possible to design a material with high contrast (e.g. high elastic constants K1 and K av ), low temperature stability, low operating voltage, and suitable LC media with slow response time. Therefore, the overall image quality in such devices still needs to be further improved.

[0018] The object of the present invention is to provide LC media, in particular for energy-saving FFS and IPS displays, but also for TN, positive VA, or STN displays, and in particular for active-matrix displays (such as those addressed by TFTs), which do not exhibit the disadvantages indicated above, or exhibit them only to a lesser extent, and which have a high elastic constant K1, as well as a low rotational viscosity and a relatively low birefringence Δn. Furthermore, such LC media need to have a high specific resistance, a low threshold voltage, a high dielectric anisotropy, good low-temperature stability (LTS), a fast response time, and achieve high brightness. In the case of FFS displays, further optimization of response time, contrast, brightness, and reliability is desirable. However, it has been found that prior art LC materials are generally unable to simultaneously achieve all of these requirements.

[0019] Surprisingly, the above technical problem is solved by providing LC media as described and claimed below.

[0020] It has now been found that, surprisingly, LC media according to the invention containing a combination of compounds of the formula I, LP1 and / or LP2

[0021]

[0022] wherein each substituent is as specified in claim 1,

[0023] Several significant improvements are demonstrated, especially when used in FFS mode displays, such as a high elastic constant K1 as well as low rotational viscosity and good solubility, and fast response time and low operating voltage are achieved.

[0024] Furthermore, the LC media according to the present invention have high-definition bright spots, excellent low-temperature stability (LTS), and offer optimal motion picture quality and improved overall picture quality, in particular high contrast.

[0025] The present invention relates to an LC medium, characterised in that the LC medium comprises one or more compounds of formula I

[0026]

[0027] where the individual substituents have the following meanings on each occurrence, identically or differently and independently of one another:

[0028] R 1 is an H atom, 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 CH2 groups are optionally replaced by: -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO-, in such a way that the O atoms are not directly bonded 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, preferably a cyclopentyl or cyclopentyloxy group,

[0029] L 1 To L 4 are independently H or F,

[0030] X 1 is -CN, -SCN, or a halogen atom,

[0031] Y 0 is H atom or CH3,

[0032] n is 0 or 1; and

[0033] One or more compounds selected from the group consisting of the following formulae LP1 and LP2:

[0034]

[0035] where the individual substituents have the following meanings on each occurrence, identically or differently and independently of one another:

[0036] R 0 is an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms, wherein one or more CH2 groups are optionally replaced by: -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO-, in such a manner that the O atoms are not directly bonded to one another and wherein one or more H atoms may be replaced by a halogen atom,

[0037] R 2 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-, in such a manner that the O atoms are not directly bonded to one another and wherein one or more H atoms may be replaced by a halogen atom,

[0038] L 1 and L 2 are independently H, F or Cl,

[0039] Y 0 is H or CH3,

[0040] m is 0, 1 or 2; and

[0041]

[0042] where the individual substituents have the following meanings on each occurrence, identically or differently and independently of one another:

[0043] R 0 is an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms, wherein one or more CH2 groups are optionally replaced by: -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO-, in such a manner that the O atoms are not directly bonded to one another and wherein one or more H atoms may be replaced by a halogen atom,

[0044] L 1 and L 2 are independently H, F or Cl,

[0045] X 2 is an F atom 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 an F atom,

[0046] Y 0 is H or CH3,

[0047] m is 0, 1 or 2.

[0048] The LC media according to the invention are particularly suitable for energy-saving LC displays in the FFS, HB-FFS, XB-FFS and IPS modes, which are generally based on positive dielectric liquid crystals and polymer-stabilized variants thereof.

[0049] The invention further relates to the use of the LC media described above and below for electro-optical purposes, in particular in 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 energy-saving FFS, HB-FFS, IPS, PS-HB-FFS and PS-IPS displays.

[0050] The invention further relates to an electro-optical energy-saving 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.

[0051] In this application, all atoms also include their isotopes. In some embodiments, one or more hydrogen atoms (H) may be optionally replaced by deuterium (D); a higher degree of deuteration enables or simplifies analytical determination of the compound, especially in the case of low concentrations.

[0052] In formulas I, LP1 and LP2, if R 0 、R 1 or R 2If R represents alkyl and / or alkoxy, this may be linear or branched. It is preferably linear, has 2, 3, 4, 5 or 6 carbon atoms, and preferably represents ethyl, propyl, butyl, pentyl, hexyl, ethoxy, propoxy, butoxy, pentyloxy or hexyloxy, as well as methyl or methoxy. 0 Preferably it represents straight-chain alkyl having 1 to 6 C atoms or alkenyl having 2 to 6 C atoms.

[0053] Oxaalkyl preferably represents straight-chain 2-oxapropyl (=methoxymethyl), 2-(=ethoxymethyl) or 3-oxabutyl (=2-methoxyethyl), 2-oxapentyl, 3-oxapentyl or 4-oxapentyl, 2-oxahexyl, 3-oxahexyl, 4-oxahexyl or 5-oxahexyl.

[0054] If R 0 、R 1 or R 2 represents an alkoxy group or an oxaalkyl group, it may also contain one or more additional oxygen atoms, with the proviso that the oxygen atoms are not directly bonded to one another.

[0055] In another preferred embodiment, R 0 、R 1 and R 2 One or more of are selected from the group consisting of: -S 1 -F, -OS 1 -F, -O-S1-O-S2, where S 1 C 1-12 Alkylene or C 2-12 Alkenylene and S 2 H, C 1-12 Alkyl or C 2-12 Alkenyl, and very preferably R 0 、R 1 and R 2 One or more of are selected from the group consisting of: -OCH2OCH3, -O(CH2)2OCH3, -O(CH2)3OCH3, -O(CH2)4OCH3, -O(CH2)2F, -O(CH2)3F, -O(CH2)4F.

[0056] If R 0 、R 1 or R 2If alkylene radicals denote an alkenyl radical, this may be straight-chain or branched. It is preferably straight-chain and has 2 to 10 C atoms. Thus, it denotes in particular vinyl, prop-1-enyl or prop-2-enyl, but-1-enyl, but-2-enyl or but-3-enyl, pent-1-enyl, pent-2-enyl, pent-3-enyl or pent-4-enyl, hex-1-enyl, hex-2-enyl, hex-3-enyl, hex-4-enyl or hex-5-enyl, hept-1-enyl, hept-2-enyl, hept-3-enyl, hept-4-enyl, hept-5-enyl or hept-6-enyl, oct-1-enyl, oct- -2-enyl, oct-3-enyl, oct-4-enyl, oct-5-enyl, oct-6-enyl or oct-7-enyl, non-1-enyl, non-2-enyl, non-3-enyl, non-4-enyl, non-5-enyl, non-6-enyl, non-7-enyl or non-8-enyl, dec-1-enyl, dec-2-enyl, dec-3-enyl, dec-4-enyl, dec-5-enyl, dec-6-enyl, dec-7-enyl, dec-8-enyl or dec-9-enyl.

[0057] If R 0 、R 1 or R 2 If represents an alkyl or alkenyl group which is at least monosubstituted by halogen, this group is preferably straight-chain, and the halogen is preferably F or Cl. In the case of polysubstitution, the halogen is preferably F. The resulting groups also include perfluorinated groups. In the case of monosubstitution, the fluorine or chlorine substituent can be located in any desired position, but is preferably located in the ω-position.

[0058] In Formula I, X 1 Preferably, it is CN or a halogen atom, and most preferably CN. In formula LP2, X 2 Preferably it is an F atom or a monofluorinated or polyfluorinated alkyl or alkoxy group having 1, 2 or 3 C atoms, or a monofluorinated or polyfluorinated alkenyl group having 2 or 3 C atoms. 2 Particularly preferred are F, CF3, CHF2, OCF3, OCHF2, OCFHCF3, OCFHCHF2, OCFHCHF2, OCF2CH3, OCF2CHF2, OCF2CHF2, OCF2CF2CHF2, OCF2CF2CHF2, OCFHCF2CF3, OCFHCF2CHF2, OCF2CF2CF3, OCH═CF2 or CH═CF2, very particularly preferably F or CF3, furthermore OCF3, OCF═CF2, OCHF2 or OCH═CF2.

[0059] In the compounds of formula I and its subformulae, R 1 Preferably represents a straight-chain alkyl or alkoxy radical having 1 to 6 C atoms, very preferably represents a methyl, ethyl or propyl radical, most preferably represents an n-propyl radical. Preferred compounds of formula I are those in which L1 or L 2 Those compounds that represent F atoms. 3 and L 4 Both preferably represent H atoms.

[0060] In a preferred embodiment, the compound of formula I can be selected from those of the following sub-formulae I-1 to I-8:

[0061]

[0062]

[0063] in

[0064] R 1 represents an H atom, 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 CH2 groups are optionally replaced by: -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO-, in such a way that the O atoms are not directly bonded to one another and in which one or more H atoms may be replaced by a halogen atom, preferably an F atom, or a cycloalkyl or cycloalkoxy group having 3 to 6 C atoms, in which one or more H atoms may be replaced by a halogen atom, preferably a cyclopentyl or cyclopentyloxy group,

[0065] X 1 represents -CN or a halogen atom, preferably -CN, and

[0066] Y 0 represents an H atom or CH 3 , preferably an H atom.

[0067] Although the substituent R in formula I 1 The choice of is not particularly limited, but R 1 It is particularly advantageous to be an alkyl or cycloalkyl radical having 1 to 6 C atoms, wherein R 1 is selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, and is particularly preferably cyclopentyl. 0 It can also be represented by a CH3 group.

[0068] In particular, the selection of compounds of the following formula I has proven to be very advantageous:

[0069]

[0070]

[0071]

[0072]

[0073] Among them, "alkyl" and "alkyl*" represent C 1-6 alkyl,

[0074] "Cycloalkyl" means C 3-6 Cycloalkyl, preferably one of the following groups:

[0075]

[0076] The proportion of compounds of the formula I or preferably of subformulae I-1-1 or I-1-2 thereof in the LC medium is preferably 1% to 20% by weight, very preferably 3% to 15% by weight, most preferably 4% to 10% by weight.

[0077] The compounds of the general formula LP1 and LP2 can be represented by one of the following:

[0078]

[0079] in

[0080] R 0 is an alkyl radical 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-, in such a way that the O atoms are not directly bonded to one another and in which one or more H atoms may be replaced by a halogen atom, preferably alkyl having 1 to 4 C atoms, alkenyl or alkenyloxy having 2 to 6 C atoms or cycloalkyl or cycloalkyloxy having 3 to 6 C atoms, with vinyl, allyl or cyclopentyl being particularly preferred,

[0081] n represents 1, 2, 3, 4, or 5, and

[0082] m represents 1, 2, 3 or 4.

[0083] In another embodiment, one or more compounds of Formula LP1 and LP2 are described by Formula LP1-1 and LP2-1:

[0084]

[0085] in

[0086] R 0 is an alkyl 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-, in such a manner that the O atoms are not directly bonded to one another and wherein one or more H atoms may be replaced by a halogen atom,

[0087] R 2 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-, in such a manner that the O atoms are not directly bonded to one another and wherein one or more H atoms may be replaced by a halogen atom,

[0088] X 2 is an F atom or an alkyl or alkoxy group having 1 to 3 C atoms or an alkenyl or alkenyloxy group having 2 to 3 C atoms, wherein one or more H atoms are replaced by an F atom, and

[0089] Y 0 is H or CH3.

[0090] Particularly preferred compounds of formula LP1 are those selected from the group consisting of the following subformulae:

[0091]

[0092]

[0093]

[0094] where Y 0 It is H or CH3, preferably H.

[0095] The compounds of formula LP1-1a, LP1-1b and LP1-1c are particularly preferred, and the compound of formula LP1-1a is most preferred.

[0096] Particularly preferred compounds of formula LP2 are those selected from the group consisting of the following subformulae:

[0097]

[0098]

[0099] where Y 0 It is H or CH3, preferably H.

[0100] The compounds of formula LP2-1a, LP2-1b, LP2-1c, LP2-1d and LP2-1i are particularly preferred, and the compound of formula LP2-1b is most preferred.

[0101] The proportion of compounds of the formula LP1 or LP2 or subformulae thereof in the LC medium is preferably from 2% to 35% by weight, very preferably from 3% to 30% by weight, most preferably from 4% to 20% by weight.

[0102] Preferably, the LC medium contains 1, 2 or 3 compounds of the formula LP1 or LP2 or subformulae thereof.

[0103] Other components

[0104] In a preferred embodiment, the LC medium may also comprise one or more compounds selected from the following formulae II and III:

[0105]

[0106] where the individual substituents, independently of one another and identically or differently on each occurrence, have the following meanings:

[0107] for

[0108] for

[0109] R 0 With formula I for R 1 One of the meanings given,

[0110] X 0 are independently of one another F, Cl, halogenated alkyl, halogenated alkenyl, halogenated alkoxy or halogenated alkenyloxy with up to 6 C atoms,

[0111] L 1-6 are independently H or F, and

[0112] Y 0 is H or CH3.

[0113] Preferred compounds of formula II and III are those wherein Y 0 Those compounds where H

[0114] 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 or propyl radical, and X 0 represents F or OCF3, very preferably those compounds where F is present.

[0115] In a preferred embodiment, the medium comprises one or more compounds of formula II selected from the following subformulae:

[0116]

[0117]

[0118] where R 0 and X 0 has the meaning given in formula II.

[0119] Preferred compounds are those of the formulae II-1, II-2 and II-3, very preferably those of the formulae II-1 and II-2.

[0120] In the compounds of formulae II-1 to II-7, R 0 preferably represents an alkyl radical having 1 to 6 C atoms, very preferably an ethyl or propyl radical, and X 0 Preferably it represents F or OCF3, very preferably it represents F.

[0121] In one embodiment, the LC medium contains one or more compounds of formula II or its subformulae as described above and below, wherein Y 0 is CH 3 . Very preferably, the medium according to this preferred embodiment comprises one or more compounds of formula II selected from the following subformulae:

[0122]

[0123] where R 0 and X 0 has the meaning given in formula II.

[0124] Preferred compounds are those of the formulae IIA-1, IIA-2 and IIA-3, very preferably those of the formulae IIA-1 and IIA-2.

[0125] In the compounds of Formulae IIA-1 to IIA-7, R 0 preferably represents an alkyl radical having 1 to 6 C atoms, very preferably an ethyl or propyl radical, and X 0 Preferably it represents F or OCF3, very preferably it represents F.

[0126] The proportion of compounds of the formula II in the LC medium is preferably from 0% to 20% by weight, very preferably from 1% to 15% by weight, most preferably from 2% to 10% by weight.

[0127] In another preferred embodiment, the medium comprises one or more compounds of formula III selected from the following subformulae:

[0128]

[0129]

[0130]

[0131]

[0132] where R 0 and X 0 has the meaning given in formula II.

[0133] Preferred compounds are those of formula III-1, III-4, III-6, III-16, III-19 and III-20.

[0134] In the compounds of formulae III-1 to III-21, R 0 preferably represents an alkyl radical having 1 to 6 C atoms, very preferably an ethyl or propyl radical, X 0 Preferably represents F or OCF3, very preferably F, and Y 2 Preferably it represents F.

[0135] The medium may also contain one or more compounds of formula III or its subformulae as described above and below, wherein Y 0 is CH 3 . Very preferably, the medium according to this preferred embodiment comprises one or more compounds of formula III selected from the following subformulae:

[0136]

[0137]

[0138]

[0139]

[0140] where R 0 and X 0 has the meaning given in formula III.

[0141] Preferred compounds are those of Formula IIIA-1, IIIA-4, IIIA-6, IIIA-16, IIIA-19 and IIIA-20.

[0142] In the compounds of formula IIIA-1 to IIIA-21, R 0 preferably represents an alkyl radical having 1 to 6 C atoms, very preferably an ethyl or propyl radical, X 0 Preferably represents F or OCF3, very preferably F, and Y 2 Preferably it represents F.

[0143] 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, most preferably from 20% to 40% by weight.

[0144] In a further preferred embodiment, the LC medium may additionally comprise one or more compounds selected from the following formulae:

[0145]

[0146] in

[0147] R 0 、X 0 、L 1-4 and Y 0 has the meaning indicated in formula II and III,

[0148] 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

[0149] s represents 0 or 1.

[0150] The compound of formula IV is preferably selected from the following formulae:

[0151]

[0152] where R 0 and X 0 have the meanings indicated in formula II and III.

[0153] R 0 Preferably represents an alkyl radical having 1 to 6 C atoms. 0 Preferably it represents F or OCF3, furthermore it represents OCF=CF2 or Cl.

[0154] The compound of formula IVa is preferably represented by the following sub-formula:

[0155]

[0156] The compound of formula IVb is preferably represented by the following formula:

[0157]

[0158] The compound of formula IVc is preferably represented by the following sub-formula:

[0159]

[0160] where R 0 has the meaning indicated in formula II and is preferably propyl or pentyl.

[0161] The compound(s) 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 1% to 20% by weight, particularly preferably 2% to 15% by weight.

[0162] The compounds of formula V are preferably selected from the following sub-formulae:

[0163]

[0164]

[0165] where R 0 and X 0 has the meaning indicated in formula II.

[0166] R 0 Preferably represents an alkyl radical having 1 to 6 C atoms. 0 Preferably, it represents F and OCF3, and further preferably represents OCHF2, CF3, OCF=CF2 and OCH=CF2.

[0167] The compound of formula VI is preferably selected from the following sub-formulae:

[0168]

[0169] where R 0 and X 0 has the meaning indicated in formula II.

[0170] R 0 Preferably represents an alkyl radical having 1 to 6 C atoms. 0 It preferably represents F, and further represents OCF3, CF3, CF=CF2, OCHF2 and OCH=CF2.

[0171] The compound of formula VII is preferably selected from the following subformulae:

[0172]

[0173] where R 0 and X 0 has the meaning indicated in formula II.

[0174] R 0 Preferably represents an alkyl radical having 1 to 6 C atoms. 0 It preferably represents F, and further preferably represents OCF3, OCHF2 and OCH=CF2.

[0175] In some embodiments, the medium further comprises one or more compounds selected from the following formulae:

[0176]

[0177]

[0178] in

[0179] R 0 and X 0 Each independently of one another has one of the meanings indicated in formula II,

[0180] L 1-4 Each independently represents H or F,

[0181] Y 0 represents H or CH3, preferably H,

[0182] X 0 Preferably F, Cl, CF3, OCF3 or OCHF2,

[0183] R 0 Preferably it denotes alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl, each having up to 6 C atoms.

[0184] Very preferably, the LC media according to the invention comprise one or more compounds of the formula XXa,

[0185]

[0186] where R 0 R has the meaning indicated in formula LP1. 0 Preferably denotes straight-chain alkyl, in particular ethyl, n-propyl, n-butyl or n-pentyl, and very particularly preferably n-propyl.

[0187] The compound(s) 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.

[0188] Very preferably, the medium according to the invention comprises one or more compounds of formula XXIa,

[0189]

[0190] where R 0 R has the meaning indicated in formula LP1. 0 Preferably denotes straight-chain alkyl, in particular ethyl, n-propyl, n-butyl or n-pentyl, and very particularly preferably n-propyl.

[0191] The compound(s) 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.

[0192] Further preferably, the medium according to the invention comprises one or more compounds of formula XXIIIa,

[0193]

[0194] where R 0 R has the meaning indicated in formula LP1. 0 Preferably it denotes straight-chain alkyl, in particular ethyl, n-propyl, n-butyl or n-pentyl, and very preferably n-propyl.

[0195] The compound(s) 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.

[0196] The medium may additionally comprise one or more compounds of formula XXIV:

[0197]

[0198] where R 0 、X 0 and L 1-6 has the meaning indicated in formula III, s represents 0 or 1, and express

[0199] In Formula XXIV, X 0 It may also represent an alkyl group having 1 to 6 C atoms or an alkoxy group having 1 to 6 C atoms. The alkyl or alkoxy group is preferably straight-chain.

[0200] R 0 Preferably represents an alkyl radical having 1 to 6 C atoms. 0 Preferably it represents F.

[0201] The compound of formula XXIV is preferably selected from the following sub-formulae:

[0202]

[0203]

[0204] where R 0 、X 0 and L 1 R has the meaning indicated in formula III. 0 Preferably represents an alkyl radical having 1 to 6 C atoms. 0 Preferably represents F, and L 1 Preferably F;

[0205] Preferably

[0206] R 0 is a straight-chain alkyl or alkenyl group having 2 to 6 C atoms.

[0207] The medium may further comprise one or more compounds of the formula:

[0208]

[0209] where R 1 and X 0 Respectively have the formula I for R 1 and X 1 The meaning indicated. 1 Preferably represents an alkyl radical having 1 to 6 C atoms. 0 Preferably represents F or Cl. In formula XXV, X 0 Preferably it represents Cl.

[0210] The medium comprises one or more compounds of the formula:

[0211]

[0212] where R 1 and X 0 Respectively have the formula I for R 1 and X 1 The meaning indicated. 1 Preferably represents an alkyl radical having 1 to 6 C atoms. 0 Preferably represents F. The medium according to the invention particularly preferably comprises one or more compounds of the formula XXIX, in which X 0 Preferably it represents F.

[0213] The compound(s) of the formula XXVI-XXIX are preferably used in the LC media according to the invention in an amount 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.

[0214] Very preferably, the LC media according to the invention comprise one or more compounds of the formula XXIXa:

[0215]

[0216] where R 1 has the meanings indicated in formula I and preferably denotes straight-chain alkyl, in particular ethyl, n-propyl, n-butyl or n-pentyl, and very preferably n-propyl.

[0217] The compound(s) of the formula XXIXa 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.

[0218] The medium may further comprise one or more compounds of the following formula:

[0219]

[0220] where R 1 and X 0 Respectively have the formula I for R 1 and X 1 The meaning indicated. 1 Preferably represents an alkyl radical having 1 to 6 C atoms. 0 Preferably represents F. The medium according to the invention particularly preferably comprises one or more compounds of the formula XXX-1, in which X 0 Preferably represents F. The compound(s) of the formulae XXX-1 to XXX-3 are preferably used in the LC media according to the invention in an amount of 1% to 20% by weight, particularly preferably 1% to 15% by weight.

[0221] Preferably, the LC medium contains, in addition to the compounds of formula I, LP1 and / or LP2 and optionally II and / or III, one or more compounds selected from the group consisting of:

[0222]

[0223]

[0224] in

[0225] "alkyl" and "alkyl*" are independently C 1-6 Alkyl, and preferably represents ethyl, propyl, butyl or pentyl, very preferably ethyl, propyl or butyl

[0226] "Alkenyl" and "alkenyl*" preferably represent C 2-6 Compounds of formula Z1 and Z2 are particularly preferred.

[0227] Preferred compounds of formula Z1 to Z6 are those selected from the following sub-formulae:

[0228]

[0229]

[0230]

[0231] In another preferred embodiment, the LC medium contains one or more compounds of formula Z1 or preferred subformulae thereof and / or one or more compounds selected from formulae Z2, Z3, Z4 and Z5 or preferred subformulae thereof.

[0232] Preferably, the total proportion of compounds of 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, and most preferably from 25% to 55% by weight. In a further preferred embodiment, the compound of formula Z1-1 is used in a concentration ranging from 10% to 60% by weight, more preferably from 25% to 50% by weight, based on the total weight of the LC medium. In another preferred embodiment, the LC medium comprises a total of 50% to 70% by weight of compounds represented by formulae Z1-1 and Z4-2.

[0233] Preferably, the medium contains 1, 2 or 3 compounds selected from the group consisting of formulae Z1, Z2, Z3 and Z4 or subformulae thereof.

[0234] The LC medium may additionally comprise one or more compounds of the following general formula:

[0235]

[0236] in

[0237] R 1 and R 2 Each independently represents C 1-6 Alkyl, C 1-6 Alkoxy or C 2-6 Alkenyl.

[0238] The compound of formula XII is preferably selected from the following sub-formulae:

[0239]

[0240]

[0241] Here, "alkyl" and "alkyl*" each independently represent methyl, butyl, pentyl or hexyl.

[0242] 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.

[0243] Particularly preferred compounds of formula XII are described by the following structure:

[0244]

[0245] The LC medium may additionally comprise one or more compounds selected from the following formulae:

[0246]

[0247] Among them L 1 and L 2 has the meaning indicated in Formula I, 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.

[0248] The medium may further comprise one or more compounds of formula XIV, wherein the substituent R 1 and R 2 At least one of represents an alkenyl group having 2 to 6 C atoms, preferably those selected from the following sub-formulae:

[0249]

[0250] Therein, "alkyl" and "alkyl*" have the meanings indicated above and each independently of one another preferably denotes methyl, ethyl or propyl.

[0251] The compound of formula XIV is preferably selected from the following sub-formulae:

[0252]

[0253]

[0254] Very preferred are compounds of the formulae XIVd-1, XIVe-1, XIVe-2 and XIVe-3.

[0255] In yet another embodiment, the LC medium comprises one or more compounds of formula XVI,

[0256]

[0257] where R 1 and R 2 have the meanings indicated in formulae I and LP1 and preferably each independently of one another denote an alkyl group having 1 to 6 C atoms. L denotes H or F.

[0258] Particularly preferred compounds of formula XVI are those of the following sub-formula

[0259]

[0260]

[0261] in

[0262] "Alkyl" and "alkyl*" each independently of one another denote a straight-chain alkyl radical having 1 to 6 C atoms, in particular ethyl, propyl or pentyl, and

[0263] "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.

[0264] Particularly preferred are compounds of the formulae XVIb and XVIc. Very particularly preferred are compounds of the following sub-formulae:

[0265]

[0266]

[0267] Very preferred are compounds of formula XVIc-2.

[0268] The LC medium may optionally comprise one or more compounds of the formula:

[0269]

[0270] in

[0271] R 1 and R 2 have the meanings indicated in formulae I and LP1 and preferably each independently of one another denote an alkyl group having 1 to 6 C atoms. L denotes H or F.

[0272] Very preferred are compounds of formula XVIIa, wherein L is H. Very preferred are compounds of formula XVIIb, wherein L is F.

[0273] In another preferred embodiment, the LC medium comprises one or more compounds of the following formula S:

[0274]

[0275] The substituents have the following meanings:

[0276] R 1 and R 2Each independently of one another is an H atom, 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-,

[0277] -O-, -CO-O- or -O-CO-, in such a way that the O atoms are not directly bonded 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,

[0278] R 3 is 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 replaced by: -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO-, in such a way that the O atoms are not directly bonded to one another;

[0279] A 0 、A 1 、A 2 each independently of one another represents phenylene-1,4-diyl (in which, 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 (in which, 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,

[0280] 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,

[0281] k and l each independently represent 0, 1, 2 or 3.

[0282] Preferred are compounds of formula S, wherein A 0 represents phenylene-1,4-diyl, 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, OCH3, OCHF2, CF3 or OCF3. Particularly preferred is wherein A 0 Represents the following compound:

[0283]

[0284]

[0285] More preferred

[0286] and very particularly preferably wherein

[0287] A 0 express

[0288] Preferred compounds of the formula S give rise to media having particularly high bright spots, low rotational viscosity, a broad nematic phase, high birefringence and excellent thermal and UV stability.

[0289] Particularly preferred compounds of formula S are those selected from the following subformulae:

[0290]

[0291]

[0292] where R 1 、R 2 and R 3 has the meaning indicated in the general formula S, and L 1 To L 6 R independently represents H or F. 1 and R 2 wherein preferably represents an optionally fluorinated alkyl or alkoxy group having 1 to 12 C atoms, an optionally fluorinated alkenyl or alkynyl group having 2 to 12 C atoms, an optionally fluorinated cycloalkyl group having 3 to 12 C atoms, and R 3 Preferably it represents H or methyl.

[0293] Particularly preferred are optionally fluorinated alkyl, alkenyl or alkynyl groups having 1 to 5 C atoms. 2 Preferably, it represents F. In formula S-1-4 to formula S-1-6, L 3 and L 4 Preferably represents H. In formulas S-1-4 to S-1-6, L 3 and L4 Preferably it represents F.

[0294] In a particularly preferred embodiment, the compound of formula S is represented by the following structure:

[0295]

[0296] where R 1 has the same meaning as in Formula S, and

[0297] R 2 represents a straight-chain or branched alkyl or alkoxy group having 1 to 7 C atoms, or an alkenyl, alkenyloxy, alkoxyalkyl group having 1 to 7 C atoms, or a cycloalkyl or cycloalkoxy 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-, in such a manner that the O atoms are not directly bonded to one another and wherein one or more H atoms may be replaced by a halogen atom;

[0298] R 3 represents an H atom or a methyl group; and

[0299] L 1 and L 2 Each independently represents an H atom or F, preferably F.

[0300] In a preferred embodiment according to the invention, the LC medium contains, in addition to the compounds of formula I, LP1 and / or LP2, II and / or III, one or more compounds selected from the group consisting of formulae Y and B:

[0301]

[0302] where the individual substituents have the following meanings on each occurrence, identically or differently and independently of one another:

[0303] for

[0304] for

[0305]

[0306] for

[0307] R 1 、R 2With formula I for R 1 One of the meanings given,

[0308] R 3 With R 1 One of the meanings given,

[0309] Z x , Z y is -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CO-O-, -O-CO-, -C2F4-, -CF=CF-, -CH=CH-CH2O-, or a single bond, preferably a single bond,

[0310] Z z is CH2O, -O-, -C2H4-, -OCH2- or a single bond,

[0311] Y 1 is -CH2-, -O- or -S-,

[0312] L 1-4 is H, F or Cl, preferably H or F, very preferably F,

[0313] x, y are 0, 1 or 2, where x+y≤3,

[0314] z is 0 or 1,

[0315] Wherein in formula B, dibenzofuran or dibenzothienyl may be further substituted by methyl or methoxy, and

[0316] The compound of formula Y contains at least one substituent L which is F or Cl, preferably F 1-4 .

[0317] Preferably, the LC medium according to this first preferred embodiment contains one or more compounds of formula I, LP1 and / or LP2, II and / or III, one or more compounds selected from formulae Z1, Z2 and Z3 and one or more compounds selected from formulae Y and B.

[0318] The LC media according to this first preferred embodiment are particularly suitable for LC displays in HB-FFS or PS-HB-FFS mode.

[0319] In the compounds of formula Y and its subformulas, R 1 and R 2 It preferably represents straight-chain alkyl or alkoxy having 1 to 6 C atoms, furthermore represents alkenyl having 2 to 6 C atoms, in particular vinyl, 1E-propenyl, 1E-butenyl, 3-butenyl, 1E-pentenyl, 3E-pentenyl or 4-pentenyl.

[0320] In the compounds of formula Y and its subformulae, preferably the substituent L 1 and L 2 Both represent F. In another preferred embodiment of the present invention, in the compounds of formula Y and its subformulae, the substituent L 1 and L 2 One represents F and the other represents Cl.

[0321] In a preferred embodiment of the present invention, the medium contains one or more compounds of formula Y selected from the group consisting of

[0322]

[0323] Among them L 1 、L 2 、R 1 、R 2 , Z x , Z y , x and y have the meanings given in formula Y or one of the preferred meanings given above in formula I,

[0324] a means 1 or 2,

[0325] b represents 0 or 1,

[0326] express

[0327] express

[0328] L 3 、L 4 represents F or Cl, preferably F, and

[0329] L 5 Represents an H atom or CH3.

[0330] Preferably, in the compounds of formula Y1 and Y2, L 1 and L 2 Both represent F or L 1 and L 2 One of them represents F and the other represents Cl, or L 3 and L 4 Both represent F or L 3 and L 4 One represents F and the other represents Cl.

[0331] Preferably, the medium comprises one or more compounds of formula Y1 selected from the group consisting of the following subformulae:

[0332]

[0333]

[0334]

[0335]

[0336]

[0337]

[0338]

[0339]

[0340]

[0341]

[0342]

[0343]

[0344] in

[0345] a means 1 or 2,

[0346] "alkyl" and "alkyl*" each independently represent a straight-chain alkyl group having 1 to 6 C atoms,

[0347] "Alkenyl" means a straight-chain alkenyl radical having 2 to 6 C atoms, and

[0348] L 5 Represents an H atom or CH3.

[0349] "Alkenyl" preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0350] Very preferably, the medium contains one or more compounds of formula Y1 selected from the group consisting of formulae Y1-1, Y1-2, Y1-7, Y1-12, Y1-17, Y1-22, Y1-40, Y1-41, Y1-42, Y1-44, Y1-50 and Y1-68. 5 Preferably it represents an H atom.

[0351] Further preferably, the medium comprises one or more compounds of formula Y2 selected from the group consisting of the following subformulae:

[0352]

[0353]

[0354]

[0355]

[0356]

[0357]

[0358]

[0359] in

[0360] "alkyl" and "alkyl*" each independently represent a straight-chain alkyl group having 1 to 6 C atoms,

[0361] "Alkenyl" means a straight-chain alkenyl group having 2 to 6 C atoms,

[0362] (O) represents an oxygen atom or a single bond, and

[0363] L 5 represents an H atom or CH 3 , preferably an H atom.

[0364] "Alkenyl" preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0365] Very preferably, the medium contains one or more compounds of the formula Y2 selected from the group consisting of formulae Y2-2 and Y2-10.

[0366] The proportion of compounds of the formula Y1 or its subformulae in the LC medium is preferably from 0% to 10% by weight.

[0367] The proportion of compounds of the formula Y2 or subformulae thereof in the LC medium is preferably from 0% to 10% by weight.

[0368] The total proportion of compounds of the formulae Y1 and Y2 or subformulae thereof in the medium is preferably from 1% to 20% by weight, very preferably from 2% to 15% by weight.

[0369] Preferably, the medium contains 1, 2 or 3 compounds of the formulae Y1 and Y2 or subformulae thereof, very preferably selected from the group consisting of the formulae Y1-2, Y1-22, Y1-66, Y1-70, Y2-6 and Y2-22.

[0370] In another preferred embodiment of the invention, the medium contains one or more compounds of formula Y selected from the following subformulae:

[0371]

[0372] Among them L 1 、L 2 、R 1 and R 2 has one of the meanings given in formula Y or one of the preferred meanings given in formula I and LP1.

[0373] Preferred compounds of formula Y3 are selected from the group consisting of the following subformulae:

[0374]

[0375]

[0376]

[0377] in,

[0378] "alkyl" and "alkyl*" each independently represent a straight-chain alkyl group having 1 to 6 C atoms;

[0379] "alkenyl" and "alkenyl*" each independently represent a straight-chain alkenyl group having 2 to 6 C atoms; and

[0380] O represents an oxygen atom or a single bond.

[0381] "Alkenyl" and "alkenyl*" preferably represent CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0382] Particularly preferred compounds of formula Y3 are selected from the group consisting of the following subformulae:

[0383]

[0384] Here, "alkoxy" and "alkoxy*" each independently of one another preferably denote a straight-chain alkoxy group having 3, 4 or 5 C atoms.

[0385] Preferably, in the compounds of formula Y3 and its subformulae, L 1 and L 2Both represent F. Further preferably, in the compound of formula Y3, the substituent L 1 and L 2 One represents F and the other represents Cl.

[0386] The proportion of compounds of the formula Y3 or its subformulae in the medium is preferably from 1% to 10% by weight, very preferably from 1% to 6% by weight.

[0387] Preferably, the LC medium contains 1, 2 or 3 compounds of the formula Y3 or a subformulae thereof, preferably of the formula Y3-6, very preferably of the formula Y3-6A.

[0388] In another preferred embodiment of the present invention, the LC medium contains one or more compounds of formula Y selected from subformula Y4

[0389]

[0390] where R 1 and R 2 each independently of one another has one of the meanings indicated above in formula Y, and

[0391]

[0392] Each independently expresses

[0393]

[0394] Among them L 5 represents F or Cl, preferably F, and L 6 represents F, Cl, OCF3, CF3, CH3, CH2F or CHF2, preferably F, and preferably at least one of rings G, I and K is different from unsubstituted benzene.

[0395] Preferred compounds of formula Y4 are selected from the group consisting of the following subformulae:

[0396]

[0397]

[0398] wherein R represents a straight-chain alkyl or alkoxy group having 1 to 7 C atoms, and R* represents a straight-chain alkenyl group having 2 to 7 C atoms,

[0399] (O) represents an oxygen atom or a single bond, and m represents an integer of 1 to 6.

[0400] R* preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-,

[0401] CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0402] R preferably represents methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy or pentoxy.

[0403] The proportion of compounds of the formula Y4 or its subformulae in the medium is preferably from 1% to 10% by weight, very preferably from 1% to 6% by weight.

[0404] Particularly preferred compounds are those of the following sub-formula:

[0405]

[0406] in

[0407] "Alkyl" and "alkyl*" each independently of one another denote a straight-chain alkyl group having 1 to 6 C atoms, in particular ethyl, propyl or pentyl.

[0408] The following compounds are particularly advantageously used:

[0409]

[0410] In another preferred embodiment of the present invention, the medium contains one or more compounds of formula Y selected from the group consisting of the following subformulae:

[0411]

[0412]

[0413] in

[0414] R 5 With the above in formula Y for R 1 One of the meanings indicated,

[0415] "alkyl" means a straight-chain alkyl group having 1 to 6 C atoms,

[0416] L x Indicates H or F,

[0417] d represents 0 or 1, and

[0418] z and m each independently represent an integer of 1 to 6.

[0419] The R 5 C is particularly preferred 2-6 Alkyl or alkoxy, or C 2-6alkenyl, d is preferably 1. The LC media according to the invention preferably comprise one or more compounds of the above formulae in an amount of ≥5% by weight.

[0420] In the compounds of formula B and its subformulas, R 1 and R 3 Preferably, it represents straight-chain alkyl or alkoxy having 1 to 6 C atoms, in particular methoxy, ethoxy, propoxy or butoxy, furthermore alkenyl having 2 to 6 C atoms, in particular vinyl, 1E-propenyl, 1E-butenyl, 3-butenyl, 1E-pentenyl, 3E-pentenyl or 4-pentenyl.

[0421] Further preferred embodiments are indicated below:

[0422] - the LC medium comprises one or more compounds of formula Y selected from the following sub-formulae:

[0423]

[0424] where R 1 、R 2 、L 1 、L 2 , X, x, and Z x has the meanings given in formula Y, and wherein at least one of the rings X is cyclohexenylene.

[0425] Preferably, the substituent L 1 and L 2 Both represent F. Further preferably, the substituent L 1 and L 2 One represents F and the other represents Cl.

[0426] The compound of formula LY is preferably selected from the group consisting of the following subformulae:

[0427]

[0428]

[0429] where R 1 R has the meaning indicated above in formula Y, (O) represents an oxygen atom or a single bond, and v represents an integer from 1 to 6. 1 Preferably represents a straight-chain alkyl radical having 1 to 6 C atoms or a straight-chain alkenyl radical having 2 to 6 C atoms, in particular CH3, C2H5, n-C3H7, n-C4H9, n-C5H 11, CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0430] Very preferred are compounds of formula LY4.

[0431] Preferably, the medium contains 1, 2 or 3 compounds of formula LY, very preferably formula LY4.

[0432] The proportion of compounds of the formula LY or its subformulae in the medium is preferably from 1% to 10% by weight.

[0433] - the medium comprises one or more compounds of formula Y selected from the following subformulae:

[0434]

[0435] where R 1 、R 2 、L 1 、L 2 , Y, y and Z y has the meanings given in formula Y, and wherein at least one of the rings Y is tetrahydropyran.

[0436] The compound of formula AY is preferably selected from the group consisting of the following subformulae:

[0437]

[0438]

[0439]

[0440] in

[0441] R 1 has the meaning indicated above,

[0442] "alkyl" means a straight-chain alkyl group having 1 to 6 C atoms,

[0443] (O) represents an oxygen atom or a single bond, and

[0444] v represents an integer from 1 to 6.

[0445] R 1 Preferably represents a straight-chain alkyl radical having 1 to 6 C atoms or a straight-chain alkenyl radical having 2 to 6 C atoms, in particular CH3, C2H5, n-C3H7, n-C4H9, n-C5H 11, CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0446] In a preferred embodiment of the invention, the medium contains one or more compounds of formula B selected from the following subformulae:

[0447]

[0448] Among them L 1 、L 2 、R 1 and R 3 has the meaning given in formula B.

[0449] Preferred compounds of formula B1 are selected from the following sub-formulae:

[0450]

[0451] where R 1 and R 3 independently represents a straight-chain alkyl group 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-, in such a way that the O atoms are not directly bonded to one another and one or more H atoms may be replaced by a halogen atom. Very preferred are compounds of the formulae B1-1 and B1-2, in which both radicals (O) represent oxygen atoms and R 1 and R 3 independently represents an alkyl group which is methyl, ethyl, propyl, butyl, pentyl or hexyl, which is preferably linear. Very preferably, one "alkyl" is ethyl and the other "alkyl*" is n-pentyl.

[0452] Very preferred are compounds of formula B1-2.

[0453] Preferably, the compound of formula B1-1 is selected from the group consisting of compounds of formulae B1-1-1 to B1-1-11, preferably compounds of formula B1-1-6,

[0454]

[0455]

[0456] in

[0457] "alkyl" and "alkyl*" each independently represent a straight-chain alkyl group having 1 to 6 C atoms,

[0458] "alkenyl" and "alkenyl*" each independently represent a straight-chain alkenyl group having 2 to 6 C atoms,

[0459] “Alkoxy” and “alkoxy*” each independently of one another represent a straight-chain alkoxy group having 1 to 6 C atoms.

[0460] Preferably, the compound of formula B1-2 is selected from the group consisting of compounds of formulae B1-2-1 to B1-2-10, preferably compounds of formula B1-2-6:

[0461]

[0462]

[0463] in

[0464] "alkyl" and "alkyl*" each independently represent a straight-chain alkyl group having 1 to 6 C atoms,

[0465] "alkenyl" and "alkenyl*" each independently represent a straight-chain alkenyl group having 2 to 6 C atoms,

[0466] “Alkoxy” and “alkoxy*” each independently of one another represent a straight-chain alkoxy group having 1 to 6 C atoms.

[0467] Optionally, the medium comprises one or more compounds of formula B1-1A and / or B1-2A:

[0468]

[0469] in

[0470] (O) represents O or a single bond,

[0471] R IIIA represents an alkyl or alkenyl group having up to 7 C atoms or a group Cy-C m H 2m+1 -,

[0472] m and n, identically or differently, are 0, 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, very preferably 1,

[0473] Cy denotes cycloaliphatic having 3, 4 or 5 ring atoms, optionally substituted by alkyl or alkenyl each having up to 3 C atoms or by halogen or CN, and preferably denotes cyclopropyl, cyclobutyl or cyclopentyl.

[0474] Preferably, additionally, alternatively or in addition to the compounds of the formulae B1-1 and B1-2, compounds of the formulae B1-1A and / or B1-2A may be present in the LC medium.

[0475] Very preferably, the compound of formula B1-1A and / or B1-2A is the following:

[0476]

[0477] wherein alkoxy represents a straight-chain alkoxy group having 1 to 6 C atoms or alternatively represents -(CH2) n F (wherein n is 2, 3, 4 or 5), preferably represents C2H4F.

[0478] The proportion of compounds of the formula B1 or its subformulae in the medium is preferably from 1% to 20% by weight, very preferably from 1% to 15% by weight.

[0479] Preferably, the medium contains 1, 2 or 3 compounds of formula B1 or subformulae thereof.

[0480] In a preferred embodiment of the present invention, the medium may comprise one or more compounds of formula B2-2:

[0481]

[0482] in

[0483] R 1 、R 3 Identically or differently represent H, alkyl or alkoxy groups having 1 to 6 C atoms, wherein one or more CH2 groups in these groups are optionally substituted independently of one another by: -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO-, in such a way that the O atoms are not directly bonded to one another and, in addition, wherein one or more H atoms may be replaced by halogen.

[0484] The compound of formula B2-2 is preferably selected from the group consisting of compounds of formulae B2-2-1 to B2-2-10:

[0485]

[0486]

[0487] where R 3 represents an alkyl group having 1 to 6 C atoms, preferably an ethyl, n-propyl or n-butyl group, or alternatively a cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl group, or alternatively -(CH2) nF, wherein n is 2, 3, 4 or 5, preferably C2H4F.

[0488] Particularly preferred compounds of formula B2 are selected from the following subformulae:

[0489]

[0490] The proportion of compounds of the formula B2 or its subformulae in the LC medium is preferably from 1% to 20% by weight, very preferably from 1% to 15% by weight.

[0491] Preferably, the LC medium contains 1, 2 or 3 compounds of the formula B2 or a subformulae thereof.

[0492] Preferred compounds of formula B3 are selected from the following sub-formulae:

[0493]

[0494] where R 1 has one of the meanings given in formula B3 and preferably represents straight-chain alkyl having 1 to 6 C atoms, very preferably represents methyl, ethyl, propyl, butyl, pentyl or hexyl, more preferably represents ethyl or propyl, most preferably represents propyl, and X 1 has one of the meanings given in formula B3 and preferably represents CF3 or OCF3.

[0495] Preferred compounds of formula B3 are selected from the following sub-formulae:

[0496]

[0497] where R 1 has one of the meanings given for formula B3 and preferably denotes straight-chain alkyl having 1 to 6 C atoms, very preferably methyl, ethyl, propyl, butyl, pentyl or hexyl, more preferably ethyl or propyl, most preferably propyl.

[0498] The most preferred are compounds of formula B3-1-1 and B3-2-2.

[0499] In a preferred embodiment, the medium contains one or more compounds of the formula B or its subformulae B1, B2, B3, B1-1, B1-2, B2-1, B2-2, B2-3, B3-1, B3-2, B3-1-1, B3-1-2, B3-2-1 and B3-2-2, in which the dibenzofuran or dibenzothiophenyl radical is substituted by a methyl or methoxy radical, preferably by a methyl radical, preferably in the para position to the substituent F, very preferably in the para position to the substituent F (i.e., at the terminal R 2 or X 1 substituted at the meta position.

[0500] The proportion of compounds of the formula B3 or its subformulae in the LC medium is preferably from 1% to 20% by weight, very preferably from 1% to 10% by weight.

[0501] Preferably, the LC medium contains 1, 2 or 3 compounds of the formula B3 or a subformulae thereof.

[0502] Preferably, the total proportion of compounds of the formulae Y and B or subformulae thereof in the LC medium is from 2% to 25% by weight, very preferably from 3% to 20% by weight.

[0503] The medium may additionally contain one or more compounds of the formula:

[0504]

[0505] Among them, L, R 1 and R 2 They have the formula LP1 for L 1 、R 0 and R 2 The meaning indicated. 1 and R 2 Preferably it denotes alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl, each having up to 6 C atoms.

[0506] In another embodiment, the LC medium may comprise one or more compounds of the formula:

[0507]

[0508] where R 1 and R 2 With formula I for R 1 The meaning indicated.

[0509] Preferably, R 1 represents an alkyl or alkenyl group having 1 to 6 or 2 to 6 C atoms, respectively, and R 2 represents an alkenyl group having 2 to 6 C atoms.

[0510] Preferred compounds of formula XXXIV include in particular

[0511]

[0512] Here, "alkyl" represents an alkyl group having 1 to 6 C atoms.

[0513] In some other embodiments, the medium comprises one or more compounds of the formula:

[0514]

[0515] where R 1 and R2 have the meanings indicated in formulae I and LP1, respectively, and preferably each independently of one another represent an alkyl group having 1 to 6 C atoms.

[0516] Compounds of formula ST

[0517] In some preferred embodiments of the present invention, the LC medium may further comprise one or more compounds of the general formula ST:

[0518]

[0519] The substituents have the following meanings:

[0520] express

[0521] X 21 、X 22 Each independently represents -O-, -CH2-, -CHR 23 -or-NR 23 -,

[0522] R 21 and R 22 each independently of one another 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-, in such a way that the O atoms are not directly bonded 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,

[0523] R 23 represents an H atom, an alkyl group or an alkoxy group having 1 to 10 C atoms,

[0524] r represents 0 or 1.

[0525] LC media comprising compounds of the following subformulae ST-1, ST-2 and ST-3 exhibit particularly high long-term thermal and UV stability:

[0526]

[0527] The substituents have the following meanings:

[0528] express

[0529] 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

[0530] r represents 0 or 1.

[0531] In a particularly preferred embodiment, the compound of the general formula ST can be selected from the following specific structures:

[0532]

[0533]

[0534]

[0535]

[0536] In a further preferred embodiment, the LC media according to the invention may comprise at least one further sterically hindered phenol, which are mentioned in Table G below.

[0537] Further preferred LC media are selected from the following preferred embodiments, including any combination thereof:

[0538] Compounds of formula I in combination with compounds of formula LP1, IV and / or XII, II and / or III

[0539] Compounds of formula I in combination with compounds of formula LP2, IV and / or XII, II and / or III

[0540] Compounds of formula I in combination with compounds of formula LP1, IV and / or XII, II and / or III and compounds of formula Z1

[0541] Compounds of formula I in combination with compounds of formula LP2, IV and / or XII, II and / or III and compounds of formula Z1

[0542] -LC medium comprises one or more compounds of formula I or its subformulae and LP1 and / or LP2, IV and / or XII, II and / or III and one or more compounds selected from the group consisting of: formula Z1, Z2, Z3, Z4, Z5, II, III, IV, V, VI, VII, VIII, LP1-1, LP2-1, XIV, XV, XVI, XVIIa, XVIIb, XVIIc, XVIII, XIX, XX, XXI, XXIII, XXIV, XXV, XXVI, XXVII, XXVIII, XXIX, XXX-1, XXX-2, XXX-3, XXXI, XXXII, XXXIII and XXXIV and subformulae thereof.

[0543] -LC medium comprising one or more compounds of formula I or its subformulae and LP1 and / or LP2, II and / or III and one or more compounds selected from the group consisting of formula Z1, Z2, Z3, Z4, Z5, II, III, IV, VI, XII, XIV, XIV, XVIIa, XVIIb, XVIIc, XX, LP1-1, LP2-1, XXIII, XXIX, XXXI and XXXIV and subformulae thereof.

[0544] The LC medium comprises one or more compounds selected from the group consisting of formulae II-1, II-2, and II-3, very preferably from the group consisting of 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.

[0545] The 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, particularly preferably from the group consisting of formulae III-1, III-6, III-16, and III-20. The individual concentrations of these compounds are preferably 2% to 15% by weight. The total concentration of these compounds is preferably 5% to 30% by weight.

[0546] The medium contains one or more compounds of formula IV, preferably selected from the group consisting of formula IVa or IVc, very preferably selected from the group consisting of formula IVa-1 or IVc-1, and most preferably selected from the group consisting of 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.

[0547] - The medium contains one or more compounds of formula VI, preferably selected from 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.

[0548] The medium contains one or more compounds of the formula Z1, preferably selected from the group consisting of the formula Z1-1. The total concentration of these compounds is preferably from 1% to 25% by weight.

[0549] The medium contains one or more compounds of the formula Z2, preferably selected from the group consisting of the formulae Z2-1 and Z2-2. The total concentration of these compounds is preferably 2% to 35% by weight, very preferably 3% to 25% by weight.

[0550] The medium comprises 5% to 20% by weight of a compound of formula Z3, preferably a compound of formula Z3-1.

[0551] The medium comprises 5% to 20% by weight of a compound of formula Z4, preferably a compound of formula Z4-1.

[0552] The medium comprises from 10% to 65% by weight, very preferably from 20% to 60% by weight, of the compound of the formula Z5.

[0553] The medium contains one or more compounds of the formula LP1-1, preferably LP1-1a or LP1-1b, very preferably LP1-1a. The concentration of these compounds is preferably 2% to 15% by weight.

[0554] The medium comprises from 1% to 15% by weight of the compound of formula LP2-1b.

[0555] The medium contains one or more compounds of formula XII, preferably formula XIIa or formula XIIb, very preferably formula XIIa, most preferably formula XIIa-1. The concentration of these compounds is preferably 2% to 15% by weight.

[0556] The medium comprises from 1% to 15% by weight of the compound of formula XIIb.

[0557] The medium contains 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 2% to 10% by weight.

[0558] The medium contains one or more compounds of the formula XVIb, preferably compounds of the formula XVIb-1, XVIb-2 and / or XVIb-3. The concentration of these compounds is preferably 2% to 15% by weight.

[0559] - The medium contains one or more compounds of formula XVIc, preferably compounds of formula XVIc-1, XVIc-2 and / or XVIc-3. The concentration of these compounds is preferably 2% to 20% by weight.

[0560] The medium contains one or more compounds of the formula XVIb, preferably compounds of the formula XVIb-1 and / or XVIb-2. The total concentration of these compounds is preferably 5% to 25% by weight.

[0561] The medium comprises one or more compounds selected from the group consisting of formulae XVIIa, XVIIb and XVIIc, very preferably formula XVIIa (wherein L is H) and formula XVIIb (wherein L is F). The total concentration of these compounds is preferably 0.5% to 5% by weight.

[0562] The medium contains 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.

[0563] The medium contains one or more compounds of the formula XXI, preferably compounds of the formula XXIa. The concentration of these compounds is preferably from 2% to 10% by weight.

[0564] The medium contains one or more compounds of the formula XXIII, preferably compounds of the formula XXIIIa. The concentration of these compounds is preferably between 0.5% and 5% by weight.

[0565] The medium contains one or more compounds of the formula XXIX, preferably compounds of the formula XXIXa. The concentration of these compounds is preferably 2% to 10% by weight.

[0566] The medium contains one or more compounds of the formula XXX. The concentration of these compounds is preferably from 2% to 10% by weight.

[0567] The medium contains one or more compounds of the formula XXXI. The concentration of these compounds is preferably from 2% to 10% by weight.

[0568] The medium contains one or more compounds of the formula XXXII. The concentration of these compounds is preferably from 2% to 10% by weight.

[0569] The medium contains one or more compounds of the formula XXXIV. The concentration of these compounds is preferably from 1% to 5% by weight.

[0570] -The medium comprises one or more compounds of formula I, preferably formula I-1 and LP1 and / or LP2, II and / or III; one or more compounds selected from the group consisting of formula Z1, Z2 and Z3 or subformulas thereof; one or more compounds selected from the group consisting of formula IV, VI, XX, XXIII and XXIX or subformulas thereof; and one or more compounds selected from the group consisting of formula LP1-1, LP2-1, XVI, XVIIa, XVIIb, XVIIc, XXXI and XXXIV or subformulas thereof.

[0571] -LC medium comprises one or more compounds of formula I, preferably formula I-1, LP1 and / or LP2, II and / or III; one or more compounds selected from the group consisting of formulae Z1, Z2, Z3, Z4 and Z5 or subformulae thereof; one or more compounds selected from the group consisting of formula XIVd or subformulae thereof; one or more compounds selected from the group consisting of formulae II, III, IVc, VIb, XXa, XXIIIa and XXIXa or subformulae thereof; and one or more compounds selected from the group consisting of formulae LP1-1a, XVIb, XVIc, XVIIa, XVIIb, XVIIc, XXXI and XXXIV or subformulae thereof.

[0572] -LC medium comprises one or more compounds of formula I, preferably formula I-1, LP1 and / or LP2, II and / or III; one or more compounds selected from the group consisting of formulae Z1, Z2 and Z3 or subformulae thereof; one or more compounds selected from the group consisting of formulae Y1 and Y2; one or more compounds selected from the group consisting of formulae IV, VI, XX, XXIII and XXIX or subformulae thereof; and one or more compounds selected from the group consisting of formulae LP1-1, LP2-1, XVI, XVIIa, XVIIb, XVIIc, XXXI and XXXIV or subformulae thereof.

[0573] -LC medium comprises one or more compounds of formula I, preferably formula I-1, LP1 and / or LP2; one or more compounds selected from the group consisting of formulae Z1, Z2, Z3, Z4 and Z5 or subformulae thereof; one or more compounds of formula B, preferably selected from the group consisting of formulae B1, B2 and B3; one or more compounds of formula XIVd or subformulae thereof; one or more compounds selected from the group consisting of formulae II, III, IVc, VIb, XXa, XXIIIa and XXIXa or subformulae thereof; and one or more compounds selected from the group consisting of formulae LP1-1a, XVIb, XVIc, XVIIa, XVIIb, XVIIc, XXXI and XXXIV or subformulae thereof.

[0574] - In addition to the compound of formula I, the LC medium also comprises further compounds selected from the group consisting of compounds of the formulae Z1, Z2, Z3, IV, LP1-1, LP2-1, XIV, XVI, XVIIa, XVIIb, XVIIc, XXI, XXIII, XXIX, XXX, XXXI and XXIV or subformulae thereof.

[0575] - In addition to the compound of formula I, the LC medium also comprises further compounds selected from the group consisting of compounds of the formulae Z1, Z2, Z3, IV, LP1-1, LP2-1, XIV, XVI, XVIIa, XVIIb, XVIIc, XXI, XXIII, XXIX, XXX, XXXI and XXIV or subformulae thereof.

[0576] The proportion of compounds of the formula I or its subformulae in the medium is preferably from 1% to 30% by weight, very preferably from 2% to 25% by weight, most preferably from 2% to 20% by weight.

[0577] The proportion of compounds of the formulae Z1, Z2, Z3, Z4 and Z5 or subformulae thereof in the LC medium as a whole is from 10% to 65% by weight, very preferably from 20% to 60% by weight.

[0578] The proportion of the compound of the formula Y or a subformula thereof in the LC medium as a whole is from 0% to 15% by weight, very preferably from 2% to 10% by weight.

[0579] 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.

[0580] 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 30% to 60% by weight.

[0581] The proportion of the compounds of the formulae XIV, XVIIa-c and XXXI-XXXIII in the LC medium as a whole is from 0.5% to 15% by weight.

[0582] The term "alkyl" or "alkyl*" in this 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.

[0583] 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, in particular CH2=CH, CH3CH=CH, are generally preferred.

[0584] 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.

[0585] The term "oxaalkyl" or "alkoxy" preferably encompasses groups of 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 also contain one or more additional O atoms in such a manner that the oxygen atoms are not directly connected to each other.

[0586] By appropriately selecting R in formula II and III 0 and X 0 The meaning of can modify the addressing time, threshold voltage, steepness of the transmission characteristic curve, etc. in a desired manner. For example, compared to alkyl and alkoxy groups, 1E-alkenyl, 3E-alkenyl, 2E-alkenyloxy, etc. generally lead to shorter addressing times, improved nematic tendencies, and a higher ratio between the elastic constants K3 (bend) and K1 (splay). Compared to alkyl and alkoxy groups, 4-alkenyl, 3-alkenyl, etc. generally give lower threshold voltages and lower K3 / K1 values. The LC media according to the present invention are particularly characterized by high Δε values ​​and thus have significantly faster response times compared to LC media of the prior art.

[0587] The optimum mixing ratio of the compounds of the above formulae depends essentially on the desired properties, the choice of the components of the above formulae and any additional components that may be present.

[0588] An appropriate mixing ratio within the above-indicated range can be easily determined depending on the specific situation.

[0589] The total amount of compounds of the above formula in the LC media according to the invention is not critical. Thus, the LC media may contain one or more further components for optimizing various properties. However, the higher the total concentration of compounds of the above formula, the greater the effect observed on the desired improvement in the properties of the media.

[0590] 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 0represents F, OCF3, OCHF2, OCH=CF2, OCF=CF2, or OCF2-CF2H. The favorable synergistic effect with the compounds of formula I, LP1 and / or LP2, II, and III results in particularly advantageous properties. In particular, LC media comprising compounds of formula I, LP1 and / or LP2, II, and III are characterized by their low threshold voltage.

[0591] The individual compounds of the formulae and subformulae mentioned above which can be used in the LC media according to the invention are known or can be prepared analogously to known compounds.

[0592] The present invention also relates to a process for preparing the LC media described above and below, by mixing one or more compounds of the formula I with one or more compounds of the formula LP1 and / or LP2 and one or more compounds selected from the group consisting of formula II, III, Z1, Z2, Z3, Z4, IV, VI, XIV, LP1-1, LP2-1, XVI, XVIIa, XVIIb, XVIIc, XX, XXIII, XXIX, XXXI and XXXIV.

[0593] In another preferred embodiment of the present invention, the LC medium additionally comprises one or more polymerizable compounds. The polymerizable compounds are preferably selected from the group consisting of formula M

[0594] R a -B 1 -(Z b -B 2 ) m -R b M

[0595] wherein the substituents, which are identical or different on each occurrence and independently of one another, have the following meanings:

[0596] 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 independently of one another be replaced by -C(R 0 )=C(R 00 )-、-C≡C-、-N(R 00 )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, 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 B2 Contains saturated C atoms, R a and / or R b It can also represent a group spiro-linked to this saturated C atom,

[0597] The substituent R a and R b At least one of represents or contains a group P or P-Sp-,

[0598] P represents a polymerizable group,

[0599] Sp represents a spacer group or a single bond,

[0600] B 1 and B 2 is an aromatic, heteroaromatic, alicyclic or heterocyclic radical, preferably having 4 to 25 ring atoms, which may also contain fused rings, and which is unsubstituted or mono- or polysubstituted by L,

[0601] 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,

[0602] R 0 and R 00 each independently of one another represents H or an alkyl group having 1 to 12 C atoms,

[0603] m represents 0, 1, 2, 3 or 4,

[0604] n1 means 1, 2, 3 or 4,

[0605] 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, where, in addition, one or more H atoms may be replaced by F, Cl, P or P-Sp-,

[0606] P and Sp have the meanings indicated above in formula M,

[0607] Y 1 represents halogen,

[0608] 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.

[0609] Particularly preferred compounds of formula M are those wherein B 1 and B 2 each independently of one another represents 1,4-phenylene, 1,3-phenylene, naphthalene-1,4-diyl, naphthalene-2,6-diyl, phenanthrene-2,7-diyl, 9,10-dihydro-phenanthrene-2,7-diyl, anthracene-2,7-diyl, fluorene-2,7-diyl, coumarin, flavonoids, wherein in addition, one or more CH groups in these groups may be replaced by N, cyclohexane-1,4-diyl, wherein in addition, one or more non-adjacent CH2 groups may be replaced by O and / or S, 1,4-phenylene Cyclohexenyl, bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, piperidine-1,4-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, indane-2,5-diyl or octahydro-4,7-methanoindane-2,5-diyl, all of which may be unsubstituted or mono- or poly-substituted by L in the above formula M.

[0610] Particularly preferred compounds of formula M are those wherein B 1 and B 2 those which each independently of one another represent 1,4-phenylene, 1,3-phenylene, naphthalene-1,4-diyl or naphthalene-2,6-diyl,

[0611] Very preferred compounds of formula M are selected from the following formulae:

[0612]

[0613]

[0614]

[0615]

[0616]

[0617] where the individual substituents have the following meanings on each occurrence, identically or differently and independently of one another:

[0618] P 1 、P 2 、P 3 is a polymerizable group, preferably selected from vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxy groups,

[0619] Sp 1 、Sp 2 、Sp 3 is a single bond or a spacer group, and wherein the substituent P 1 -Sp 1 -、P 1 -Sp 2 - and P 3 -Sp 3 -One or more of them can represent R aa , the restriction being the presence of the substituent P 1 -Sp 1 -、P 2 -Sp 2 and P 3 -Sp 3 -At least one of them is different from R aa , preferably -(CH2) p1 -、-(CH2) p1 -O-, -(CH2) p1 -CO-O- or -(CH2) p1 -O-CO-O-, wherein p1 is an integer from 1 to 12,

[0620] R aa is H, F, Cl, CN or a straight-chain or branched alkyl radical having 1 to 25 C atoms, wherein one or more non-adjacent CH2 groups may each independently of one another be replaced by: -C(R 0 )=C(R 00)-、-C≡C-、-N(R 0 )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, in such a way that the O atoms and / or S atoms are not directly bonded to each other, and in addition, one or more H atoms may be bonded via F, Cl, CN or P 1 -Sp 1 - instead, particularly preferably a straight-chain or branched, optionally monofluorinated or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy radical having 1 to 12 C atoms, where alkenyl and alkynyl radicals have at least two C atoms and branched radicals have at least three C atoms,

[0621] R 0 、R 00 is H or an alkyl group having 1 to 12 C atoms,

[0622] R y and R z is H, F, CH3 or CF3,

[0623] X 1 、X 2 、X 3 is -CO-O-, -O-CO- or a single bond,

[0624] Z M1 -O-, -CO-, -C(R y R z )- or -CF2CF2-,

[0625] Z M2 , Z M3 -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CF2O-, -OCF2- or -(CH2) n -, where n is 2, 3, or 4,

[0626] L is F, Cl, CN or a linear or branched, optionally monofluorinated or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy radical having 1 to 12 C atoms,

[0627] L', L" are H, F or Cl,

[0628] r is 0, 1, 2, 3, or 4,

[0629] s is 0, 1, 2, or 3,

[0630] t is 0, 1, or 2,

[0631] x is 0 or 1.

[0632] Particularly preferred are compounds of formulae M2 and M13.

[0633] Further preferred are trireactive compounds of M15 to M31, especially M17, M18, M19, M22, M23, M24, M25, M30 and M31.

[0634] In the compounds of formulae M1 to M31, the group

[0635] Preferably

[0636]

[0637] wherein L has, identically or differently at each occurrence, one of the meanings given above or below for formula M and is preferably F, Cl, CN, NO2, CH3, C2H5, C(CH3)3, CH(CH3)2, CH2CH(CH3)C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5 or P-Sp-, very preferably F, Cl, CN, CH3, C2H5, OCH3, COCH3, OCF3 or P-Sp-, more preferably F, Cl, CH3, OCH3, COCH3 or OCF3, in particular F or CH3.

[0638] Preferred compounds of formula M1 to M31 are those wherein P 1 、P 2 and P 3 Those representing acrylate, methacrylate, oxetane or epoxy groups, very preferably acrylate or methacrylate groups.

[0639] Further preferred compounds of formula M1 to M31 are those wherein Sp 1 、Sp 2 and Sp 3 Those that are single bonds.

[0640] Further preferred compounds of formula M1 to M31 are those wherein Sp 1 、Sp 2 and Sp 3 One of them is a single bond, and Sp 1 、Sp 2 and Sp 3 The other one in is different from those of single bonds.

[0641] Further preferred compounds of the formulae M1 to M31 are those in which the group Sp which is different from a single bond is 1 、Sp 2 and Sp 3Indicates -(CH2) s1 -X"-, wherein s1 is an integer from 1 to 6, preferably 2, 3, 4 or 5, and X" is a linker to the benzene ring and is -O-, -O-CO-, -CO-O-, -O-CO-O- or a single bond.

[0642] Particular preference is given to LC media comprising one, two or three polymerisable compounds of the formula M, preferably selected from the formulae M1 to M31.

[0643] It is further preferred that the LC media according to the present invention comprise one or more polymerisable compounds selected from Table E below.

[0644] Preferably, the proportion of polymerisable compounds (preferably selected from formula M and table E) 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%.

[0645] It has been observed that the addition of one or more polymerizable compounds, such as those selected from Formula M and Table E, to the LC medium results in advantageous properties, such as fast response time. Such LC media are particularly suitable for use in PSA displays, where they exhibit low image sticking, rapid and complete polymerization, rapid development of stable low pretilt angles after UV exposure, high reliability, high VHR values ​​after UV exposure, and high birefringence. By appropriately selecting the polymerizable compound, the absorption of the LC medium at longer UV wavelengths can be increased, thereby enabling polymerization using such longer UV wavelengths, which is advantageous in the display manufacturing process.

[0646] The polymerizable group P is a group suitable for polymerization reactions, such as free radical or ionic chain polymerization, polyaddition or polycondensation, or for polymer-analogous reactions, such as addition or condensation onto the polymer backbone. Particular preference is given to groups suitable 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 (e.g., oxetane or epoxy groups).

[0647] Preferred groups P are selected from the group consisting of: CH2=CW 1 -CO-O-, CH2=CW 1 -CO-,

[0648]

[0649] CH2=CW 2 -(O) k3 -、CW 1 =CH-CO-(O) k3 -、CW 1 =CH-CO-NH-, CH2=CW 1 -CO-NH-,

[0650] CH3-CH=CH-O-, (CH2=CH)2CH-OCO-, (CH2=CH-CH2)2CH-OCO-,

[0651] (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, oxaalkyl or oxacarbonylalkyl 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 which is optionally substituted with one or more substituents L other than 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.

[0652] Very particularly preferred groups P are selected from the group consisting of: CH2=CW 1 -CO-O-, CH2=CW 1 -CO-, CH2=CW 2 -O-、CH=CW 2 -、CW 1 =CH-CO-(O) k3 -、CW1 =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, oxaalkyl or oxacarbonylalkyl 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.

[0653] Very particularly preferred groups P are selected from the group consisting of: CH2=CW 1 -CO-O-, especially CH2=CH-CO-O-, CH2=C(CH3)-CO-O- and CH2=CF-CO-O-, in addition CH2=CH-O-, (CH2=CH)2CH-O-CO-, (CH2=CH)2CH-O-,

[0654] Further preferred polymerizable groups P are selected from the group consisting of vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxy, most preferably from acrylate and methacrylate.

[0655] If Sp is different from a single bond, it preferably has the formula Sp"-X", so that the corresponding substituent P-Sp- corresponds to the formula P-Sp"-X"-, in which

[0656] 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, wherein in addition one or more non-adjacent CH2 groups may each independently of one another be replaced 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,

[0657] 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,

[0658] R 0 and R 00 each independently of one another represents H or an alkyl group having 1 to 20 C atoms, and

[0659] Y 2 and Y 3 Each independently represents H, F, Cl or CN.

[0660] X" is preferably -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR 0 -、-NR 0-CO-、-NR 0 -CO-NR 00 - or single key.

[0661] 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, R 0 and R 00 has the meaning indicated in the above formula M.

[0662] 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.

[0663] 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-methyliminoethylene, 1-methylalkylene, vinylene, propenylene and butenylene.

[0664] For the production of PSA displays, the polymerisable compounds contained in the LC medium are polymerised or crosslinked (if a compound contains two or more polymerisable groups) by in situ polymerisation in the LC medium between the liquid crystal display substrates, optionally while applying a voltage to the electrodes.

[0665] The structure of the PSA display according to the invention corresponds to the typical geometry of PSA displays, as described in the prior art cited at the outset. Preference is given to geometries without protrusions, particularly those in which the color filter-side electrodes are unstructured and only the electrodes on the TFT side have grooves. For example, US 2006 / 0066793 A1 describes a particularly suitable and preferred electrode structure for PS-VA displays.

[0666] The combination of the compounds of the above preferred embodiments with the above polymeric compounds leads to low threshold voltages, low rotational viscosities and very good low temperature stability in the LC media according to the invention, with simultaneously constant high bright spots and high VHR values.

[0667] The use of LC media containing polymerizable compounds allows the rapid establishment of particularly low pretilt angles in PSA displays. In particular, in PSA displays, the LC media exhibit significantly shortened response times, in particular grayscale response times, compared to media from the prior art.

[0668] Generally, preference is given to LC media having a nematic LC phase, preferably no chiral liquid crystal phase.

[0669] The present invention further relates to the use of an LC medium according to the invention as described above and below for electro-optical purposes, in particular in 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 type mentioned above, containing an LC medium according to the invention as described above and below, 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.

[0670] The invention further relates to an electro-optical display, such as an STN or MLC display, having two plane-parallel outer plates which together with a frame form a 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 situated in the cell, wherein the nematic LC medium is an LC medium according to the invention as described above and below.

[0671] The LC media according to the invention enable a significant broadening of the usable parameter latitude. 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.

[0672] In particular, the combination of compounds of formula I with compounds of formula LP1 and / or LP2, and optionally with compounds selected from formulae II to XXXIII or subformulae thereof, results in LC media which exhibit a moderately positive dielectric anisotropy and at the same time an 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. This allows LC displays, especially FFS, HB-FFS, XB-FFS and IPS mode LC displays, to have high brightness and transmittance as well as a low response time.

[0673] 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 FFS, HB-FFS, XB-FFS and IPS displays based on positive dielectric liquid crystals.

[0674] The LC media according to the invention enable excellent MLC displays with fast response times to be obtained while maintaining the nematic phase down to -20°C and preferably down to -30°C, particularly preferably down to -40°C, and a clearing point of ≥85°C, preferably ≥90°C, while simultaneously allowing a rotational viscosity γ1 of ≤120 mPa·s, particularly preferably ≤100 mPa·s to be obtained. The rotational viscosity is measured at 20°C.

[0675] The dielectric anisotropy Δε of the LC media according to the invention at 20° C. and 1 kHz is preferably ≧+1.5, very preferably between +3 and +18, most preferably between +5 and +15.

[0676] The birefringence Δn of the LC media according to the invention at 20° C. is preferably from 0.08 to 0.12, very preferably from 0.09 to 0.11.

[0677] The rotational viscosity γ1 of the LC medium according to the invention is preferably ≤120 mPa·s, further preferably ≤110 mPa·s and very preferably ≤90 mPa·s.

[0678] The ratio γ1 / K1 of the LC media according to the invention, where γ1 is the rotational viscosity and K1 is the elastic constant for the skew deformation, is preferably ≤7 mPa·s / pN, very preferably ≤6 mPa·s / pN, most preferably ≤5.5 mPa·s / pN.

[0679] 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., in particular at least 110° C. This range preferably extends at least from −25° C. to +90° C.

[0680] 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 (e.g. above 100° C.) at higher threshold voltages, or lower clearing points at lower threshold voltages, while maintaining other advantageous properties. It is likewise possible to obtain LC media with higher Δε and therefore lower threshold values, with a correspondingly only slightly increased viscosity. MLC displays according to the invention are preferably operated at the first Gooch and Tarry transmission minimum [C.H. Gooch and H.A. Tarry, Electron. Lett. 10, 2-4, 1974; C.H. Gooch and H.A. Tarry, Appl. Phys., Vol. 8, 1575-1584, 1975], where, in addition to particularly advantageous electro-optical properties (e.g., high characteristic line steepness 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 at the second minimum. This makes it possible to achieve significantly higher specific resistance values ​​at the first minimum using the LC media according to the invention than in the case of LC media comprising cyano compounds. By suitable selection of the individual components and their weight ratios, a person skilled in the art can set the necessary birefringence for a predetermined layer thickness in an MLC display using simple, conventional methods.

[0681] Measurements of the 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 5, 1381 (1989)] have shown that the LC media according to the present invention exhibit a significantly smaller decrease in HR upon UV exposure compared to similar LC media comprising cyano-phenylcyclohexane. The LC media according to the present invention have significantly better light and UV stability, i.e., they exhibit a significantly smaller decrease in HR upon exposure to light, heat or UV.

[0682] The structure of the MLC display according to the present invention, consisting of a polarizer, an electrode base plate, and surface-treated electrodes, conforms to the conventional design of this type of display. The term "conventional design" is used in this context in a broad sense and also encompasses all derivatives and modifications of MLC displays, in particular including matrix display elements based on polysilicon TFTs or MIMs.

[0683] However, a significant difference between the displays according to the invention and hitherto conventional displays based on twisted nematic cells lies in the choice of the LC parameters of the LC layer.

[0684] The LC media that can be used according to the invention are prepared in a conventional manner, for example by mixing one or more compounds according to claim 1 with one or more compounds of the formulae II to XXXIV or with other LC compounds and / or additives. In general, the required amount of the component used in the smaller amount is dissolved in the component constituting the main composition, advantageously at elevated temperature. It is also possible to mix solutions of the components in an organic solvent (for example in acetone, chloroform or methanol) and, after thorough mixing, remove the solvent again, for example by distillation.

[0685] The LC medium may also contain other additives known to those skilled in the art and described in the literature, such as polymerization initiators, inhibitors, surfactants, light stabilizers, antioxidants (e.g. BHT, TEMPOL), microparticles, free radical scavengers, nanoparticles, etc. For example, 0 to 15% of polychromatic dyes or chiral dopants or initiators may be added, such as 651 or 907. Suitable stabilizers and dopants are described in Tables C and D below.

[0686] In a preferred embodiment of the present invention, the LC medium contains one or more further stabilizers, preferably selected from the group consisting of:

[0687]

[0688] where the individual substituents, independently of one another and identically or differently on each occurrence, have the following meanings:

[0689] R a-d is a straight-chain or branched alkyl radical having 1 to 10, preferably 1 to 6, very preferably 1 to 4 C atoms, most preferably methyl,

[0690] X S H, CH3, OH or O ● ,

[0691] A S is a linear, branched or cyclic alkylene radical having 1 to 20 C atoms, which is optionally substituted,

[0692] n is an integer from 1 to 6, preferably 3, and

[0693] s is 0 or 1.

[0694] Preferred stabilizers of formula S3 are selected from formula S3A

[0695]

[0696] wherein n2 is an integer from 1 to 12, and wherein the group (CH2) n2One or more H atoms in are optionally replaced by methyl, ethyl, propyl, butyl, pentyl or hexyl.

[0697] Very preferred stabilizers are selected from the group consisting of:

[0698]

[0699]

[0700]

[0701] In a preferred embodiment, the LC medium comprises one or more stabilizers selected from the group consisting of formulae S1-1, S2-1, S3-1, S3-2 and S3-3.

[0702] In a preferred embodiment, the LC medium comprises one or more stabilizers selected from Table D.

[0703] Preferably, the proportion of stabilizers (such as those of the formulae S1 to S3) in the LC medium is from 10 to 2000 ppm, very preferably from 30 to 1000 ppm.

[0704] Furthermore, it is possible to add, for example, 0 to 15% by weight of polychromatic dyes, as well as nanoparticles, conductive salts (preferably ethyldimethyldodecyl ammonium 4-hexyloxybenzoate, tetrabutylammonium tetraphenylborate or complex salts of crown ethers (see, for example, Haller et al., Mol. Cryst. Liq. Cryst. 24 , 249-258 (1973))) for improving the electrical conductivity or adding substances for changing the dielectric anisotropy, viscosity and / or nematic alignment. Such substances are described, for example, in DE-A 22 09127, 22 40 864, 23 21 632, 23 38 281, 24 50 088, 26 37 430 and 28 53 728.

[0705] For the present invention and in the following examples, the structures of the LC compounds are indicated by means of acronyms, which are converted into chemical formulae according to the following Tables A to C. All substituents C m H 2m+1 、C n H 2n+1 and C l H 2l+1 or C m H 2m-1 、C n H 2n-1 and C l H 2l-1is a straight-chain alkyl or alkylene group, having n, m and 1 C atoms, respectively, in each case. Preferably, n, m and 1 are independently 1, 2, 3, 4, 5, 6 or 7. Table A shows the code of the core ring element of the compound, Table B lists the bridging unit, and Table C lists the meaning of the symbol of the left and right end groups of the molecule. The acronyms consist of the code of the ring element with an optional linking group, followed by the first hyphen and the code of the left end group, and the second hyphen and the code of the right end group. Table D shows the schematic structure of the compound and their corresponding abbreviations.

[0706] Table A: Ring elements

[0707]

[0708]

[0709]

[0710] Table B: Bridge Unit

[0711]

[0712]

[0713] Table C: End Groups

[0714]

[0715]

[0716] where n and m are each integers, and the three dots "..." are placeholders for other abbreviations from the table.

[0717] The following abbreviations are used:

[0718] (n, m, k and l are each independently an integer, preferably 1 to 12, preferably 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".)

[0719] The preferred compositions of the LC media are shown in Tables D and E.

[0720] Table D

[0721]

[0722]

[0723]

[0724]

[0725]

[0726] Table E

[0727] In the following formulae, n and m each independently of one another represent 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, in particular 2, 3, 5, and furthermore 0, 4, 6.

[0728]

[0729]

[0730]

[0731]

[0732]

[0733]

[0734]

[0735]

[0736]

[0737]

[0738]

[0739]

[0740] Particular preference is given to LC media which, in addition to the compounds of the formula I, LP1 and / or LP2, comprise at least one, two, three, four or more compounds from Table E.

[0741] Table F

[0742] 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 and particularly preferably 0.01 to 3% by weight of dopant.

[0743]

[0744]

[0745] Table G

[0746] Stabilizers which may be additionally added to the LC media according to the invention, for example in amounts of 0% to 10% by weight, are described below.

[0747]

[0748]

[0749]

[0750]

[0751]

[0752] Table H

[0753] Table H shows illustrative reactive mesogenic compounds (RMs) that can be used in the LC media according to the present invention.

[0754]

[0755]

[0756]

[0757]

[0758]

[0759]

[0760]

[0761]

[0762]

[0763]

[0764]

[0765]

[0766]

[0767]

[0768]

[0769]

[0770]

[0771]

[0772]

[0773]

[0774]

[0775] In a preferred embodiment, the mixture according to the invention comprises one or more polymerizable compounds, preferably selected from the group consisting of polymerizable compounds of formulae RM-1 to RM-182. 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- 109, RM-116, RM-117, RM-120, RM-121, RM-122, RM-139, RM-140, RM-142, RM-143, RM- 145, RM-146, RM-147, RM-149, RM-156 to RM-163, RM-169, RM-170 and RM-171 to RM-183 are particularly preferred.

[0776] Table I

[0777] Table 1 shows self-aligning additives for homeotropic alignment, which can be used in the LC medium of SA-FFS, SA-HB-FFS and SA-XB-FFS displays according to the invention:

[0778]

[0779]

[0780]

[0781]

[0782]

[0783]

[0784]

[0785]

[0786]

[0787]

[0788]

[0789] 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-48, preferably from the formulae SA-14 to SA-48, very preferably from the formulae SA-20 to SA-34 and SA-44 in combination with one or more RMs.

[0790] The following examples are intended to illustrate the present invention, not to limit the present invention.

[0791] In this context, percentage data refer to weight percentages. All temperatures are given in degrees Celsius. mp = melting point, cl.p. = clearing point. Furthermore, C = crystalline, N = nematic, S = smectic, and I = isotropic. The data between these symbols represent transition temperatures. Furthermore, the following symbols are used:

[0792] V0 represents the Freedericks threshold voltage at 20°C, capacitance [V],

[0793] V 10 represents the voltage [V] for 10% transmittance,

[0794] n e represents the extraordinary refractive index at 20°C and 589 nm,

[0795] n0 represents the ordinary refractive index at 20°C and 589 nm,

[0796] Δn represents the optical anisotropy measured at 20 °C and 589 nm,

[0797] ε ⊥ represents the dielectric constant perpendicular to the longitudinal axis of the molecule at 20°C and 1 kHz,

[0798] ε || represents the dielectric constant (or permittivity) parallel to the longitudinal axis of the molecule at 20°C and 1 kHz,

[0799] Δε represents the dielectric anisotropy at 20°C and 1 kHz,

[0800] cl.p. or T(N,I) represents the clearing point [℃],

[0801] υ represents the flow viscosity measured at 20°C [mm 2·s -1 ],

[0802] γ1 represents the rotational viscosity [mPa·s] measured at 20°C,

[0803] K1 is the elastic constant at 20°C, the “bending” deformation [pN],

[0804] K2 represents the elastic constant at 20°C, "torsion" deformation [pN],

[0805] K3 represents the elastic constant at 20°C, the "bending" deformation [pN], and

[0806] VHR stands for voltage holding ratio.

[0807] Unless expressly indicated otherwise, all physical properties are measured according to “Merck Liquid Crystals, Physical Properties of Liquid Crystals”, November 1997, Merck KGaA, Germany, and apply to a temperature of 20°C. Example

[0808] Example M1

[0809] The nematic LC medium was formulated as follows:

[0810]

[0811]

[0812] Mixture Example S1 (Stabilized by a Compound of Formula S1-1)

[0813] The nematic LC medium according to the invention is formulated as follows:

[0814] Mixture M1 99.97% by weight Compound of formula S1-1 300ppm

[0815] After UV exposure, the addition of 300 ppm of the compound of formula S1-1 significantly improved the VHR compared to the unstabilized mixture M1. 100 , without affecting the remaining physical properties of the mixture M1.

[0816]

[0817] Example M2

[0818] The nematic LC medium was formulated as follows:

[0819]

[0820]

[0821] Mixture Example S2 (Stabilized by Compound of Formula S1-1)

[0822] The nematic LC medium according to the invention is formulated as follows:

[0823] Mixture M2 99.99% by weight Compound of formula S1-1 100ppm

[0824] After UV exposure, the addition of 100 ppm of the compound of formula S1-1 significantly improved the VHR compared to the unstabilized mixture M2. 100 , without affecting the remaining physical properties of the mixture M2.

[0825] Example M3

[0826] The nematic LC medium was formulated as follows:

[0827]

[0828]

[0829] Mixture Example S3 (Stabilized with a Compound of Formula S2-1)

[0830] The nematic LC medium according to the invention is formulated as follows:

[0831] Mixture M3 99.98% by weight Compound of formula S2-1 200ppm

[0832] After UV exposure, the addition of 200 ppm of the compound of formula S2-1 significantly improved the VHR compared to the unstabilized mixture M3. 100 , without affecting the remaining physical properties of the mixture M3.

[0833]

[0834] Example M4

[0835] The nematic LC medium was formulated as follows:

[0836]

[0837]

[0838] Mixture Example S4 (Stabilized by a Compound of Formula S2-1)

[0839] The nematic LC medium according to the invention is formulated as follows:

[0840] Mixture M4 99.99% by weight Compound of formula S2-1 100ppm

[0841] After UV exposure, the addition of 100 ppm of the compound of formula S2-1 significantly improved the VHR compared to the unstabilized mixture M4. 100 , without affecting the other physical properties of mixture M4.

[0842] Example M5

[0843] The nematic LC medium was formulated as follows:

[0844]

[0845]

[0846]

[0847] Mixture Example S5 (Stabilized by a Compound of Formula S3-1)

[0848] The nematic LC medium according to the invention is formulated as follows:

[0849] Mixture M5 99.9% by weight Compound of formula S3-1 1000ppm

[0850] After UV exposure, the addition of 1000 ppm of the compound of formula S3-1 significantly improved the VHR compared to the unstabilized mixture M5. 100 , without affecting the other physical properties of mixture M5.

[0851]

[0852] Example M6

[0853] The nematic LC medium was formulated as follows:

[0854]

[0855]

[0856] Mixture Example S6 (Stabilized by Compound of Formula S3-3)

[0857] The nematic LC medium according to the invention is formulated as follows:

[0858] Mixture M6 99.99% by weight Compound of formula S3-3 100ppm

[0859] After UV exposure, the addition of 100 ppm of the compound of formula S3-3 significantly improved the VHR compared to the unstabilized mixture M6. 100 , without affecting the remaining physical properties of mixture M6.

[0860]

[0861] Example M7

[0862] The nematic LC medium was formulated as follows:

[0863]

[0864]

[0865] Mixture Example S7 (Stabilized by Compound of Formula S3-3)

[0866] The nematic LC medium according to the invention is formulated as follows:

[0867] Mixture M7 99.995% by weight Compound of formula S3-3 50ppm

[0868] After UV exposure, the addition of 50 ppm of the compound of formula S3-3 significantly improved the VHR compared to the unstabilized mixture M7. 100 , without affecting the remaining physical properties of mixture M7.

[0869] In summary, the LC media of Examples M1 to M7 and S1 to S7 have high clearing points, while the rotational viscosity γ1 and the response time parameter γ1 / K1 are low. These LC media offer improved overall image quality, particularly high contrast and short response times. Furthermore, due to their low V0 values, these LC media can operate at low voltages, making them ideal for various energy-efficient displays and mobile applications, such as car navigation systems and tablet computers.

Claims

1. A liquid crystal medium, characterized in that The liquid crystal medium comprises One or more compounds of formula I where the individual substituents have the following meanings on each occurrence, identically or differently and independently of one another: R 1 is an H atom, 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 CH2 groups are optionally replaced by the following groups: -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO-, in such a way that the O atoms are not directly bonded 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, preferably a cyclopentyl or cyclopentyloxy group, L 1 To L 4 are independently H or F, X 1 is -CN, -SCN, or a halogen atom, Y 0 is H atom or CH3, n is 0 or 1; and One or more compounds selected from the group consisting of the following formulae LP1 and LP2: where the individual substituents have the following meanings on each occurrence, identically or differently and independently of one another: R 0 is an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms, wherein one or more CH2 groups are optionally replaced by the following groups: -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO-, in such a manner that the O atoms are not directly bonded to one another and wherein one or more H atoms may be replaced by a halogen atom, R 2 is an alkyl radical having 1 to 6 C atoms, wherein one or more CH2 groups are optionally replaced by the following radicals: -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO-, in such a manner that the O atoms are not directly bonded to one another and wherein one or more H atoms may be replaced by a halogen atom, L 1 and L 2 are independently H, F or Cl, Y 0 is H or CH3, m is 0, 1 or 2; and where the individual substituents have the following meanings on each occurrence, identically or differently and independently of one another: R 0 is an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms, wherein one or more CH2 groups are optionally replaced by the following groups: -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO-, in such a manner that the O atoms are not directly bonded to one another and wherein one or more H atoms may be replaced by a halogen atom, L 1 and L 2 are independently H, F or Cl, X 2 is an F atom 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 an F atom, Y 0 is H or CH3, m is 0, 1 or 2.

2. The liquid-crystalline medium according to claim 1 , wherein the one or more compounds of formula I are selected from the group consisting of compounds of formulae I-1 to I-8: in R 1 is an H atom, 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 CH2 groups are optionally replaced by the following groups: -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO-, in such a way that the O atoms are not directly bonded 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 6 C atoms, in which one or more H atoms may be replaced by a halogen atom, X 1 is -CN or a halogen atom, and Y 0 It is an H atom or CH3.

3. Liquid-crystalline medium according to claim 1 or 2, characterized in that The one or more compounds of formula LP1 and LP2 are described by formula LP1-1 and LP2-1: in R 0 is an alkyl 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 the following groups: -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO-, in such a manner that the O atoms are not directly bonded to one another and wherein one or more H atoms may be replaced by a halogen atom, R 2 is an alkyl radical having 1 to 6 C atoms, wherein one or more CH2 groups are optionally replaced by the following radicals: -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO-, in such a manner that the O atoms are not directly bonded to one another and wherein one or more H atoms may be replaced by a halogen atom, X 2 is an F atom or an alkyl or alkoxy radical having 1 to 3 C atoms or an alkenyl or alkenyloxy radical having 2 or 3 C atoms, wherein one or more H atoms are replaced by an F atom, and Y 0 is H or CH3.

4. Liquid-crystalline medium according to one or more of claims 1 to 3, characterized in that The liquid-crystalline medium comprises one or more compounds selected from the group consisting of: where the individual substituents, independently of one another and identically or differently on each occurrence, have the following meanings: for for R 0 According to claim 1, 1 One of the meanings given, L 1-6 are independently H or F, X 0 are independently F, Cl, halogenated alkyl, halogenated alkenyl, halogenated alkoxy or halogenated alkenyloxy with up to 6 C atoms, and Y 0 is H or CH3.

5. Liquid-crystalline medium according to claim 4, wherein the one or more compounds of formula II are selected from the following sub-formulae: where R 0 and X 0 has the meaning given in formula II.

6. Liquid-crystalline medium according to claim 4 or 5, wherein the one or more compounds of formula III are selected from the following sub-formulae: where R 0 and X 0 has the meaning given in formula III.

7. Liquid-crystalline medium according to one or more of claims 1 to 6, characterized in that The liquid-crystalline medium comprises one or more compounds selected from the following formulae: "alkyl" and "alkyl*" represent C 1-6 alkyl, and "alkenyl" and "alkenyl*" indicate C 2-6 Alkenyl.

8. Liquid-crystalline medium according to one or more of claims 1 to 7, characterized in that The liquid-crystalline medium comprises one or more compounds selected from the group consisting of: where R 1 and R 2 each independently of one another represents alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl, each having up to 6 C atoms, "alkenyl" means C 2-6 alkenyl, and L 1 has the meaning indicated in claim 1.

9. Liquid-crystalline medium according to one or more of claims 1 to 8, characterized in that The liquid-crystalline medium further comprises one or more compounds selected from the group consisting of: where R 0 、X 0 、L 1 、L 2 and Y 0 has the meaning indicated in claim 4, L 3 and L 4 Independently of each other, they have 1 one of the meanings given, and 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 s represents 0 or 1.

10. Liquid-crystalline medium according to one or more of claims 1 to 9, characterized in that The liquid-crystalline medium comprises one or more compounds selected from the group consisting of: where R 0 、L 1-4 、Y 0 and X 0 Each independently of one another has one of the meanings indicated in claim 4 .

11. Liquid-crystalline medium according to one or more of claims 1 to 10, characterized in that The liquid-crystalline medium comprises one or more compounds selected from the group consisting of: where R 1 and X 0 With the R in claim 1 1 and X 1 The meaning indicated.

12. Liquid-crystalline medium according to one or more of claims 1 to 11, characterized in that The liquid-crystalline medium comprises one or more compounds of the formula I, LP1 and LP2 and one or more compounds selected from the group consisting of the following formulae: Z1, Z2, Z3, Z4, Z5, II, III, IV, VI, XIV, XX, XXIII, XXIX, XVI, XVIIa, XVIIb, XVIIc and XXX.

13. Liquid-crystalline medium according to one or more of claims 1 to 12, characterized in that The liquid-crystalline medium further comprises one or more polymerizable compounds.

14. A process for producing a liquid-crystalline medium according to one or more of claims 1 to 13, characterized in that One or more compounds of formula I and one or more compounds of formula LP1 and / or LP2 are mixed with one or more mesogenic compounds and optionally one or more polymerizable compounds or compounds of formula M and / or one or more additives.

15. Use of a liquid-crystalline medium according to one or more of claims 1 to 13 for electro-optical purposes.

16. Electro-optical liquid-crystal display comprising a liquid-crystal medium according to one or more of claims 1 to 13.

17. An electro-optical liquid crystal display according to claim 16, characterized in that The electro-optical liquid crystal display 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.

18. An electro-optical liquid crystal display according to claim 16, characterized in that The electro-optical liquid crystal display is an FFS, HB-FFS, XB-FFS, PS-HB-FFS, PS-XB-FFS, IPS or PS-IPS display.

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