Liquid-crystal medium

Abstract

The present invention relates to a liquid-crystal (LC) material as defined in claim 1, having negative dielectric anisotropy and to the use thereof for optical, electro- optical and electronic purposes, such as for example in LC displays, in particular energy saving displays based on the ECB, IPS or FFS effect.

Description

[0001] Liquid-crystal medium The present invention relates to liquid-crystal (LC) media having negative dielectric anisotropy and to the use thereof for optical, electro-optical and electronic purposes, in particular in LC displays. One of the liquid-crystal display (LCD) modes used at present is the TN (“twisted nematic”) mode. However, TN LCDs have the disadvantage of a strong viewing-angle dependence of the contrast. In addition, so-called VA (“vertically aligned”) displays are known which have a broader viewing angle. The LC cell of a VA display contains a layer of an LC medium between two transparent electrodes, where the LC medium usually has a negative dielectric anisotropy. In the switched-off state, the molecules of the LC layer are aligned perpendicular to the electrode surfaces (homeotropically) or have a tilted homeotropic alignment. On application of an electrical voltage to the two electrodes, a realignment of the LC molecules parallel to the electrode surfaces takes place. Also known are so-called IPS (“in-plane switching”) displays, which contain an LC layer between two substrates, where the two electrodes are arranged on only one of the two substrates and preferably have intermeshed, comb-shaped structures. On application of a voltage to the electrodes, an electric field which has a significant component parallel to the LC layer is thereby generated between them. This causes realignment of the LC molecules in the layer plane. Furthermore, so-called FFS (“fringe-field switching”) displays have been reported (see, inter alia, S.H. Jung et al., Jpn. J. Appl. Phys., Volume 43, No.3, 2004, 1028), which contain two electrodes on the same substrate, one of which is structured in a comb-shaped manner and the other is unstructured. A strong, so-called "fringe field" is thereby generated, i.e., a strong electric field close to the edge of the electrodes, and, throughout the cell, an electric field which has both a strong vertical component and also a strong horizontal component. FFS displays have a low viewing-angle dependence of the contrast. FFS displays usually contain an LC medium with positive dielectric anisotropy, and an alignment layer, usually of polyimide, which provides planar alignment to the molecules of the LC medium. FFS displays can be operated as active-matrix or passive-matrix displays. In the case of active-matrix displays, individual pixels are usually addressed by integrated, non-linear active elements, such as, for example, transistors (for example thin-film transistors ("TFTs")), while in the case of passive-matrix displays, individual pixels are usually addressed by the multiplex method, as known from the prior art. Furthermore, FFS displays have been disclosed (see S.H. Lee et al., Appl. Phys. Lett. 73(20), 1998, 2882-2883 and S.H. Lee et al., Liquid Crystals 39(9), 2012, 1141- 1148), which have similar electrode design and layer thickness as FFS displays but comprise a layer of an LC medium with negative dielectric anisotropy instead of an LC medium with positive dielectric anisotropy. The LC medium with negative dielectric anisotropy shows a more favorable director orientation that has less tilt and more twist orientation compared to the LC medium with positive dielectric anisotropy, as a result of which these displays have a higher transmission. The displays further comprise an alignment layer, preferably of polyimide provided on at least one of the substrates that is in contact with the LC medium and induces planar alignment of the LC molecules of the LC medium. These displays are also known as "Ultra Brightness FFS (UB-FFS)" mode displays. These displays require an LC medium with high reliability. In VA displays of the more recent type, uniform alignment of the LC molecules is restricted to a plurality of relatively small domains within the LC cell. Disclinations may exist between these domains, also known as tilt domains. VA displays having tilt domains have, compared with conventional VA displays, a greater viewing-angle independence of the contrast and the grey shades. In addition, displays of this type are simpler to produce since additional treatment of the electrode surface for uniform alignment of the molecules in the switched-on state, such as, for example, by rubbing, is no longer necessary. Instead, the preferential direction of the tilt or pretilt angle is controlled by a special design of the electrodes. In so-called MVA (“multidomain vertical alignment”) displays, this is usually achieved by the electrodes having protrusions which cause a local pretilt. As a consequence, the LC molecules are aligned parallel to the electrode surfaces in different directions in different, defined regions of the cell on application of a voltage. "Controlled" switching is thereby achieved, and the formation of interfering disclination lines is prevented. Although this arrangement improves the viewing angle of the display, it results, however, in a reduction in its transparency to light. A further development of MVA uses protrusions on only one electrode side, while the opposite electrode has slits, which improves the transparency to light. The slitted electrodes generate an inhomogeneous electric field in the LC cell on application of a voltage, meaning that controlled switching is still achieved. For further improvement of the transparency to light, the separations between the slits and protrusions can be increased, but this in turn results in a lengthening of the response times. In so-called PVA ("patterned VA") displays, protrusions are rendered completely superfluous in that both electrodes are structured by means of slits on the opposite sides, which results in increased contrast and improved transparency to light but is technologically difficult and makes the display more sensitive to mechanical influences (“tapping”, etc.). For many applications, such as, for example, monitors and especially TV screens, however, a shortening of the response times and an improvement in the contrast and luminance (transmission) of the display are demanded. A further development are displays of the so-called PS ("polymer sustained") or PSA ("polymer sustained alignment") type, for which the term "polymer stabilised" is also occasionally used. In these, a small amount (for example 0.3% by weight, typically < 1% by weight) of one or more polymerisable, compound(s), preferably polymerisable monomeric compound(s), is added to the LC medium and, after filling the LC medium into the display, is polymerised or crosslinked in situ, usually by UV photopolymerisation, optionally while a voltage is applied to the electrodes of the display. The polymerisation is carried out at a temperature where the LC medium exhibits a liquid crystal phase, usually at room temperature. The addition of polymer- isable mesogenic or liquid-crystalline compounds, also known as reactive mesogens or “RMs”, to the LC mixture has proven particularly suitable. In the meantime, the PS(A) principle is being used in various conventional LC display modes. Thus, for example, PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS and PS-TN displays are known. The polymerisation of the RMs preferably takes place with an applied voltage in the case of PS-VA and PS-OCB displays, and with or without, preferably without, an applied voltage in the case of PS-IPS displays. As can be demonstrated in test cells, the PS(A) method results in a pretilt in the cell. In the case of PS-VA displays, the pretilt has a positive effect on response times. For PS-VA displays, a standard MVA or PVA pixel and electrode layout can be used. In addition, however, it is also possible, for example, to manage with only one structured electrode side and no protrusions, which significantly simplifies production and at the same time results in very good contrast and in very good transparency to light. PS-VA displays are described, for example, in EP 1170626 A2, US 6,861,107, US 7,169,449, US 2004 / 0191428 A1, US 2006 / 0066793 A1 and US 2006 / 0103804 A1. In particular for monitor and especially TV applications, optimisation of the response times, but also of the contrast and luminance (thus also transmission) of the LC display continues to be demanded. The PSA method can provide significant advantages here. In particular in the case of PS-VA, PS-IPS and PS-FFS displays, a shortening of the response times, which correlate with a measurable pretilt in test cells, can be achieved without significant adverse effects on other parameters. Another problem observed in prior art is that the use of conventional LC media in LC displays, including but not limited to displays of the PSA type, often leads to the occurrence of mura in the display, especially when the LC medium is filled in the display cell manufactured using the one drop filling (ODF) method. This phenomenon is also known as "ODF mura". It is therefore desirable to provide LC media which lead to reduced ODF mura. Another problem observed in prior art is that LC media for use in PSA displays, including but not limited to displays of the PSA type, do often exhibit high viscosities and, as a consequence, high switching times. In order to reduce the viscosity and switching time of the LC medium, it has been suggested in prior art to add LC compounds with an alkenyl group. However, it was observed that LC media containing alkenyl compounds often show a decrease of the reliability and stability, and a decrease of the VHR especially after exposure to UV radiation. Especially for use in PSA displays this is a considerable disadvantage because the photo- polymerisation of the RMs in the PSA display is usually carried out by exposure to UV radiation, which may cause a VHR drop in the LC medium. In addition there is a great demand for PSA displays, and LC media and polymerisable compounds for use in such PSA displays, which enable a high specific resistance at the same time as a large working-temperature range, short response times, even at low temperatures, and a low threshold voltage, a low pretilt angle, a multiplicity of grey shades, high contrast and a broad viewing angle, have high reliability and high values for the VHR after UV exposure, and, in case of the polymerisable compounds, have low melting points and a high solubility in the LC host mixtures. In PSA displays for mobile applications, it is especially desired to have available LC media that show low threshold voltage and high birefringence. One display trend is to achieve fastest possible response time to have best motion picture quality. In this respect, media with negative dielectric anisotropy have an intrinsic disadvantage compared to LC media with positive dielectric anisotropy. On the other hand, mixtures with negative dielectric anisotropy enable a higher transmittance in standard FFS cell layouts and therefore its use has a positive impact on the power consumption and the environment. There is a need in the art to achieve both, fast response time and higher transmittance. Especially for use in mobile devices there is great demand for displays with high transmission, which enable the use of less intensive backlight, which, therefore, leads to longer battery lifetime, hence, more sustainable products. Alternatively, displays with higher brightness can be achieved having improved contrast especially under ambient light. Also, the popularity of 8K and gaming monitors leads to an increased need for LC display panels having higher refresh rates and thus for LC media having faster response times. There is thus still a great demand for VA, FFS or PSA displays, and LC media optionally comprising polymerisable compounds for use in VA, FFS or PSA displays, which do not show the drawbacks as described above, or only do so to a small extent, and have improved properties. The invention is based on the object of providing novel suitable LC media, which do not have the disadvantages indicated above or do so to a reduced extent. Surprisingly, it has now been found that liquid crystalline media with a suitably high negative ^ ^, a suitable phase range and ^n and high LTS can be realized which do not exhibit the drawbacks of the materials of the prior art or at least do exhibit them to a significantly lesser degree by using liquid crystalline media comprising one or more compounds of formula I defined below. The invention relates to a liquid crystal medium comprising one or more compounds of the formula I I in which R1and R2, identically or differently, denote H, halogen, straight chain alkyl or alkoxy each having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy each having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl or alkenyloxy each having 3 to 15 C atoms, where one or more CH2groups in these radicals may each be -C ^C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- in such a way that O atoms are not linked directly to one another, and where one or more H atoms may be replaced by halogen, L11, L12, L13and L14each, independently of one another, denote F, Cl, CF3or CHF2, and Y1denotes H, F, Cl, CF3, CHF2or CH3, and b) one or more compounds selected from the group of compounds of the formulae IIA, IIB, IIC and IID

[0002] in which R2A, R2B, R2Cand R2Didentically or differently, denote H, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl, alkenyloxy each having 3 to 15 C atoms, where one or more CH2groups in these radicals may each be -OCF2-, -CH=CH-, by -O-, -CO-O- or -O-CO- in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, L1, L2, L3and L4, each, independently of one another, denote F, Cl, CF3or CHF2, Y denotes H, F, Cl, CF3, CHF2or CH3, Z2, Z2Band Z2Deach, independently of one another, denote a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF- or -CH=CHCH2O-, (O) denotes O or a single bond, p denotes 0, 1 or 2, q denotes 0 or 1, and v denotes an integer from 1 to 6. The invention furthermore relates to the use of the LC media according to the invention for electro-optical purposes, preferably in displays, very preferably in displays of the VA, IPS or FFS type, in particular of the UB-FFS type. The invention furthermore relates to the use of the LC media according to the invention in PSA displays, in particular to the use in PSA displays containing an LC medium, for the production of a tilt angle in the LC medium by in-situ polymerisation of polymerisable reactive mesogens (RM) in the PSA display, preferably in an electric or magnetic field. The invention furthermore relates to an LC display comprising an LC medium according to the invention, in particular a VA, IPS, FFS or UB-FFS or PSA display, particularly preferably an FFS, UB-FFS, VA or a PS-VA display. The invention furthermore relates to the use of LC media according to the invention in polymer stabilised SA-VA displays, and to a polymer stabilised SA-VA display comprising the LC medium according to the invention. The invention furthermore relates to a process for preparing an LC medium as described above and below, comprising the steps of mixing one or more compounds of the formula I with one or more compounds of the formulae IIA, IIB, IIC and / or IID, and optionally with one or more chiral dopants, and optionally with one or more polymerisable compounds and optionally with further LC compounds and / or additives. According to another aspect of the invention there is provided an energy saving display for gaming comprising the liquid crystal medium defined above and below. In a preferred embodiment the medium for the energy saving display for gaming has a birefringence in the range of from 0.125 to 0.155. The invention furthermore relates to a process for manufacturing an LC display as described above and below, comprising the steps of filling or otherwise providing an LC medium, which optionally comprises one or more polymerisable compounds as described above and below, between the substrates of the display, and optionally polymerising the polymerisable compounds. The LC media according to the invention show the following advantageous properties, in particular when used in FFS displays: - excellent low-temperature stability (LTS) - improved contrast ratio of a display due to a favourably high Kav, - a low value ^1 / K1resulting in fast switching, - a high birefringence - high transmission of the display, - a high clearing temperature, - a high voltage-holding-ratio, - low rotational viscosity - fast switching, - fast response time that enables LCDs with low power consumption to enlarge the battery lifetime for mobile devices, - sufficient stability against heat and / or UV in particular when used outdoors, - a suitably high birefringence in combination with fast response time for use in applications for gaming. The compounds of the formula I are known from JP 2022-106268 A. Preference is given to LC media comprising the compounds of formula I in which Y1denotes H or methyl, more preferably H, and in which L11, L12, F, L13and L14denote F and in which R1and R2have the meanings defined above for formula I. Preferred compounds of the formula I are selected from the compounds of the formulae I-1 to I-36

[0003]

[0004] in which v is an integer from 1 to 6. In a preferred embodiment the medium additionally comprises one or more compounds of the formula IA in which R1and R2, identically or differently, denote H, halogen, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl or alkenyloxy each having 3 to 15 C atoms, where one or more CH2groups in these radicals may each be replaced, -OCF2-, -CH=CH-, by -O-, -CO-O- or -O-CO- in such a way that O atoms are not linked directly to one another, where one or more H atoms may be replaced by halogen, L11and L12, each, independently of one another, denote F, Cl, CF3or CHF2, preferably F, L13and L14, each, independently of one another, denote H, F, Cl, CF3or CHF2, preferably H or F, Y1denotes H, F, Cl, CF3, CHF2or CH3, preferably H, and n is 0 or 1, preferably 1. More preferred compounds of the formula IA are selected from the compounds of the formulae IAa, IAb, IAc, IAd and IAe, very preferably of the formula IAb:

[0005] in which R1and R2, identically or differently, denote straight chain alkyl having 1 to 15 C atoms, straight chain alkenyl having 2 to 15 C atoms or branched alkyl, or alkenyl having 3 to 15 C atoms, where one or more CH2groups in these radicals may each which one or more H atoms may be replaced by fluorine; preferably both of R11and R12denote straight chain alkyl having 1 to 6 C atoms. Preferred compounds of the formula IAa are selected from the compounds of the formulae IAa-1 to IAa-36.

[0006] in which v is an integer from 1 to 6. Preferred compounds of the formula IAb are selected from the compounds of the formulae IAb-1 to IAb-36.

[0007] in which v is an integer from 1 to 6. Preferred compounds of the formula IAc are selected from the compounds of the formulae IAc-1 to IAc-36.

[0008] in which v is an integer from 1 to 6. Preferred compounds of the formula IAd are selected from the compounds of the formulae IAd-1 to IAd-36. IAd-11 IAd-12 IAd-13 IAd-14 IAd-15 IAd-16 IAd-17 IAd-18

[0009] in which v is an integer from 1 to 6. Preferred compounds of the formula IAe are selected from the compounds of the formulae IAe-1 to IAe-36.

[0010] in which v is an integer from 1 to 6. Preferred compounds of the formulae IIA, IIB, IIC and IID are indicated below:

[0011] in which the parameter a denotes 1 or 2, alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, and alkenyl denotes a straight-chain alkenyl radical having 2-6 C atoms, and (O) denotes an oxygen atom or a single bond. Alkenyl preferably denotes 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-. Very preferred compounds of the formula IID are selected from the following sub- formulae:

[0012] In a preferred embodiment, the medium comprises one or more compounds of formula IID-10a in which the occurring groups and parameters have the meanings given above under formula IID, and R2denotes , in which r is 0, 1, 2, 3, 4, 5 or 6 and s is 1, 2 or 3. Preferred compounds of formula IID-10a are the compounds IID-10a-1 to IID-10a- 14. -6 -7 -8 -9 -10 -11 -12

[0013] Particularly preferred mixtures according to the invention comprise one or more compounds of the formulae IIA-2, IIA-8, IIA-10, IIA-16, IIA-18, IIA-40, IIA-41, IIA-42, IIA-43, IIB-2, IIB-10, IIB-16, IIC-1, IID-4 and IID-10. Preferred media according to the invention comprise at least one compound of the IIC-1 in which alkyl and alkyl* have the meanings indicated above. In particular, the medium comprises one or more compounds of the formula IIA-2 selected from the following sub-formulae:

[0014] Alternatively, preferably in addition to the compounds of the formulae IIA-2-1 to IIA- 2-5, the medium comprises one or more compounds of the formulae IIA-2a-1 to IIA- IIA-2a-5 In particular, the medium comprises one or more compounds of the formula IIA-10 selected from the following sub-formulae: Alternatively, preferably in addition to the compounds of the formulae IIA-10-1 to IIA- 10-5, the medium comprises one or more compounds of the formulae IIA-10a-1 to IIA-10a-5: IIA-10a-1

[0015] In particular, the medium comprises one or more compounds of the formula IIB-10 selected from the following sub-formulae:

[0016] Alternatively, preferably in addition to the compounds of the formulae IIB-10-1 to IIB- 10-5, the medium comprises one or more compounds of the formulae IIB-10a-1 to IIB-10a-5: The medium according to the invention preferably comprises one or more compounds of formula III III in which R31and R32each, independently of one another, denote H, an alkyl or alkoxy radical having 1 to 15 C atoms, where one or more CH2groups in these radicals may each be replaced, independently of one another, by , , -CH=CH-, by -O-, -CO-O- or -O-CO- in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, A31on each occurrence, independently of one another, denotes a) 1,4-cyclohexenylene or 1,4-cyclohexylene radical, in which one or two non- adjacent CH2groups may be replaced by -O- or -S-, b) a 1,4-phenylene radical, in which one or two CH groups may be replaced by N, or c) a radical from the group spiro[3.3]heptane-2,6-diyl, 1,4-bicyclo[2.2.2]- octylene, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4- tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl and fluorene-2,7-diyl, where the radicals a), b) and c) may be mono- or polysubstituted by halogen atoms, n denotes 0, 1 or 2, preferably 0 or 1, Z31on each occurrence independently of one another denotes -CO-O-, -O-CO-, -CF2O- , -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -(CH2)4-, -CH=CH-CH2O-, -C2F4-, -CH2CF2-, -CF2CH2-, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C ^C- or a single bond, and L31and L32each, independently of one another, denote F, Cl, CF3or CHF2, preferably H or F, most preferably F, and W denotes O or S. The compounds of formula III are preferably selected from the compounds of the formula III-1 and / or III-2 in which the occurring groups have the same meanings as given under formula III above and preferably R31and R32each, independently of one another, an alkyl, alkenyl or alkoxy radical having up to 15 C atoms, more preferably one or both of them denote an alkoxy radical and L31and L32each preferably denote F. Preferably, the compounds of the formula III-1 are selected from the group of compounds of the formulae III-1-1 to III-1-11, preferably of formula III-1-6,

[0017] alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms, alkoxy and alkoxy* each, independently of one another, denote a straight-chain alkoxy radical having 1-6 C atoms, and L31and L32each, independently of one another, denote F or Cl, preferably both F. Preferably, the compounds of the formula III-2 are selected from the group of compounds of the formulae III-2-1 to III-2-10, preferably of formula III-2-6,

[0018] in which alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms, alkoxy and alkoxy* each, independently of one another, denote a straight-chain alkoxy radical having 1-6 C atoms, and L31and L32each, independently of one another, denote F or Cl, preferably both F. Optionally the medium comprises one or more compounds of the formula IIIA-1 and / or IIIA-2 in which L31and L32have the same meanings as given under formula III, (O) denotes O or a single bond, RIIIAdenotes alkyl or alkenyl having up to 7 C atoms or a group Cy-CmH2m+1-, m and n are, identically or differently, 0, 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, very preferably 1, Cy denotes a cycloaliphatic group having 3, 4 or 5 ring atoms, which is optionally substituted with alkyl or alkenyl each having up to 3 C atoms, or with halogen or CN, and preferably denotes cyclopropyl, cyclobutyl, cyclopentyl, cyclopent- 1-enyl, cyclopent-2-enyl and cyclopent-3-enyl. The compounds of formula IIIA-1 and / or IIIA-2 are contained in the medium either alternatively or in addition to the compounds of formula III, preferably additionally. Very preferred compounds of the formulae IIIA-1 and IIIA-2 are the following: IIIA-1-1 IIIA-1-6 IIIA-2-1 IIIA-2-2 IIIA-2-3 IIIA-2-4 IIIA-2-5 IIIA-2-6 in which alkoxy denotes a straight-chain alkoxy radical having 1-6 C atoms or alternatively –(CH2)nF in which n is 2,3,4, or 5, preferably C2H4F. In a preferred embodiment of the present invention, the medium comprises one or more compounds of formula III-3 in which R31, R32identically or differently, denote H, an alkyl or alkoxy radical having 1 to 15 C atoms, in which one or more CH2groups in these radicals are optionally s are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by halogen. The compounds of formula III-3 are preferably selected from the group of compounds of the formulae III-3-1 to III-3-10:

[0019] in which R32denotes alkyl having 1 to 7 C-atoms, preferably ethyl, n-propyl or n- butyl, or alternatively cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl or alternatively –(CH2)nF in which n is 2,3,4, or 5, preferably C2H4F. In a preferred embodiment of the present invention, the medium comprises one or more compounds of the formulae III-4 to III-6, preferably of formula III-5,

[0020] in which the parameters have the meanings given above, R31preferably denotes straight-chain alkyl and R32preferably denotes alkoxy, each having 1 to 7 C atoms. In a preferred embodiment the medium comprises one or more compounds of the formula III selected from the group of compounds of formulae III-7 to III-9, preferably of formula III-8, in which the parameters have the meanings given above, R31preferably denotes straight-chain alkyl and R32preferably denotes alkoxy each having 1 to 7 C atoms. In a preferred embodiment, the medium comprises one or more compounds of the formula IV, IV in which R41denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms, preferably an n-alkyl radical, particularly preferably having 2, 3, 4 or 5 C atoms, and R42denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkoxy radical having 1 to 6 C atoms, both preferably having 2 to 5 C atoms, an unsubstituted alkenyl radical having 2 to 7 C atoms, preferably having 2, 3 or 4 C atoms, more preferably a vinyl radical or a 1-propenyl radical and in particular a vinyl radical. The compounds of the formula IV are preferably selected from the group of the compounds of the formulae IV-1 to IV-4, in which alkyl and alkyl’, independently of one another, denote alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms, alkenyl denotes an alkenyl radical having 2 to 5 C atoms, preferably having 2 to 4 C atoms, particularly preferably 2 C atoms, alkenyl’ denotes an alkenyl radical having 2 to 5 C atoms, preferably having 2 to 4 C atoms, particularly preferably having 2 to 3 C atoms, and alkoxy denotes alkoxy having 1 to 5 C atoms, preferably having 2 to 4 C atoms. The compounds of the formula IV-1 are preferably selected from the group of the compounds of the formulae IV-1-1 to IV-1-5

[0021] The compounds of the formula IV-2 are preferably selected from the compounds of the formulae IV-2-1 and IV-2-2 The compounds of the formula IV-3 are preferably selected from the group of the compounds of the formulae IV-3-1 and IV-3-2: in which alkyl has the meanings defined above. The compounds of the formula IV-3-1 and IV-3-2 are preferably selected from the following compounds: Very preferably, the medium according to the invention comprises a compound of formula IV-4, in particular selected from the compounds of the formulae IV-4-1 to IV-4-3 In an embodiment, the medium according to the invention comprises one or more compounds of formula I selected from the compounds of the formulae I-1 to I-4 in combination with one or more compounds selected from the group of compounds of the formulae IA-1 to IA-9:

[0022] in which alkyl denotes methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or n- pentyl. The liquid-crystalline medium preferably additionally comprises one or more compounds of the formula IVa, in which R41and R42each, independently of one another, denote a straight-chain alkyl, alkoxy, alkenyl, alkoxyalkyl or alkoxy radical having up to 12 C atoms, and Z4denotes a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -C4H8-, -CF=CF-. Preferred compounds of the formula IVa are indicated below: IVa-4 in which alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1 to 6 C atoms. The medium according to the invention preferably comprises at least one compound of the formula IVa-1and / or formula IVa-2. The proportion of compounds of the formula IVa in the mixture as a whole is preferably less than 5 % by weight, very preferably less than 2% by weight. Preferably, the medium comprises one or more compounds of formula IVb-1 to IVb-3 alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1 to 6 C atoms, and alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2 to 6 C atoms. Of the compounds of the formulae IVb-1 to IVb-3, the compounds of the formula IVb-2 are particularly preferred. Particularly preferred biphenyls are

[0023] in which alkyl* denotes an alkyl radical having 1 to 6 C atoms and preferably denotes n-propyl. The medium according to the invention particularly preferably comprises one or more compounds of the formulae IVb-1-1 and / or IVb-2-3. In a preferred embodiment, the medium according to the invention comprises one or more compounds of formula V in which R51, R52denote alkyl having 1 to 7 C atoms, alkoxy having 1 to 7 C atoms, or alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7 C atoms,

[0024] , Z51, Z52each, independently of one another, denote -CH2-CH2-, -CH2-O-, -CH=CH-, -C≡C-, -COO- or a single bond, and n is 1 or 2, where the compounds of the formula CL are excluded. The compounds of formula V are preferably selected from the compounds of the formulae V-1 to V-16:

[0025] in which R51and R52have the meanings indicated for formula V above. R51and R52preferably each, independently of one another, denote straight-chain alkyl having 1 to 7 C atoms or alkenyl having 2 to 7 C atoms. Preferred media comprise one or more compounds of the formulae V-1, V-5, V-6, V-8, V-9, V-10, V-11, V-12, V-14, V-15, and / or V-16, very preferably V-5 or V-6. Preferably, the medium according to the invention comprises one or more compounds of the formula CL in which RLdenotes H, a straight chain or branched alkyl or alkoxy radical having 1 to 15 C atoms, or a straight chain or branched alkenyl radical having 2 to 15 C atoms, where one or more CH2groups in these radicals may each be replaced, independently of such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by halogen, XLdenotes F, Cl, CN, CHF2, CF3, OCF3, or, identically or differently, has one of the meanings of RL, YLdenotes H, F, Cl or CH3. The compounds of formula CL are preferably selected form the group of compounds of the formulae CL-1, CL-2 and CL-3: in which RL1identically or differently, have the meanings given above for formula I and, preferably denote alkyl or alkenyl having 1 to 7 C atoms or 2 to 7 C atoms, respectively, in which a CH2group may be replaced by cyclopropane-1,2-diyl, and RL2alternatively denotes alkoxy having 1 to 5 C atoms. Very preferred compounds of the formula CL are selected from the compounds of the formulae CL-3-1 to CL-3-12:

[0026] In a preferred embodiment, the medium according to the invention comprises the compound CL-3-1. In a preferred embodiment of the present invention the medium additionally comprises one or more compounds of the formula VI, in which R61and R62denote H, F, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl, alkenyloxy each having 3 to 15 C atoms, where one or more CH2groups in these radicals may each be replaced, independently of one another, by such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, X61to X66, identically or differently, denote H or F, preferably at least one of X61to X66denotes F, more preferably at least two of X61to X66denote F; Z61and Z62, identically or differently, denote CH2CH2or a single bond. The compounds of the formula VI are preferably selected from the formulae VI-1 and VI-2: in which the occurring groups have the meanings given for formula VI. The compounds of the formula VI-1 are preferably selected from the formulae VI-1-1 to VI-1-21, very preferably of the formula VI-1-4:

[0027] in which R6denotes a straight-chain alkyl or alkoxy radical having 1 to 6 C atoms, (O) denotes -O- or a single bond, and m is 0, 1, 2, 3, 4, 5 or 6 and n is 0, 1, 2, 3 or 4. R preferably denotes methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentoxy. In the compounds of the formula VI-1-4, (O) preferably denotes -O-. The compounds of the formula VI-2 are preferably selected from the formulae VI-2-1 to VI-2-15, very preferably of the formula VI-2-1:

[0028] in which R6denotes a straight-chain alkyl or alkoxy radical having 1 to 6 C atoms, (O) denotes -O- or a single bond, and m is 0, 1, 2, 3, 4, 5 or 6 and n is 0, 1, 2, 3 or 4. R preferably denotes methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentoxy. In a preferred embodiment of the present invention the medium additionally comprises one or more compounds of the formulae VII-1 to VII-9 VII-1

[0029] R7denotes a straight-chain alkyl or alkoxy radical having 1 to 6 C atoms, or a straight chain alkenyl radical having 2 to 6 C atoms, and w is an integer from 1 to 6. Preferably, the medium according to the invention comprises one or more compounds of the formula VIII: in which R81and R82, identically or differently, denote H, halogen, CN, SCN, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl or alkenyloxy having 3 to 15 C atoms, where one or more CH2groups in these radicals may each be replaced, -OCF2-, -CH=CH-, by -O-, -CO-O- or -O-CO- in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, A0, A81, and A82, each, independently of one another, denote phenylene-1,4-diyl, in which 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, OCHF2or OCF3, cyclohexane-1,4-diyl, in which one or two non-adjacent CH2groups 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; Z81and Z82, each, independently of one another, denote -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; n denotes 0, 1, 2 or 3, preferably 0, 1 or 2, very preferably 0 or 1, particularly preferably 0; and m denotes 0, 1, 2 or 3, preferably 0, 1 or 2, very preferably 1 or 2, in particular 1; where the compounds of the formula I are excluded from formula VIII. A81and A82in formula I preferably denote phenylene-1,4-diyl, which may also be mono- or polysubstituted by F, furthermore cyclohexane-1,4-diyl, cyclohexenylene- 1,4-diyl, tetrahydropyran-2,5-diyl or 1,3-dioxane-2,5-diyl, very preferably phenylene- 1,4-diyl which may also be mono- or polysubstituted by F, or cyclohexane-1,4-diyl. Z81and Z82in formula I preferably denote -CF2O-, -OCF2- or a single bond, very preferably a single bond. in which L denotes halogen, CF3or CN, preferably F. Preference is furthermore given to compounds of the formula VIII in which R81and R82each, independently of one another, denote H, F, or alkyl, alkoxy, alkenyl or alkynyl having 1 to 8, preferably 1 to 5, C atoms, each of which is optionally substituted by halogen, in particular by F. R81and R82preferably denote H, optionally fluorinated alkyl or alkoxy having 1 to 7 C atoms, optionally fluorinated alkenyl or alkynyl having 2 to 7 C atoms, optionally fluorinated cycloalkyl having 3 to 12 C atoms. Preferably, at least one of R81and R82is not H, particularly preferably both of R81and R82are not H. R81is very particularly preferably alkyl. R82is furthermore preferably H, alkyl or fluorine. Very particularly preferably, R81is alkyl and R82is H or alkyl. R81, R82each, independently of one another, very particularly preferably denote unbranched alkyl having 1 to 5 C atoms. If R81and R82denote substituted alkyl, alkoxy, alkenyl or alkynyl, the total number of C atoms in the two groups R81and R82is preferably less than 10. Preferred compounds of the formula VIII are selected from the following sub- formulae, more preferably from the compounds of the formula VIII-3:

[0030] in which R81and R82have the meanings indicated above, L denotes F, and r, s and t independently are 0, 1, 2, 3, or 4. r preferably is 1 or 2, very preferably 2 and s and t independently are preferably 0 or 1, very preferably 0. R81and R82in particular independently denote n-alkyl having 1 to 5 C atoms. In a first very preferred embodiment, the compounds of the formulae VIII-1 to VIII-6 are selected from the compounds of the formula VIII-1a to VIII-6a, in particular of the formula VIII-3a:

[0031] in which R81, R82, L, r and s have the meanings defined above. In a second very preferred embodiment, the compounds of the formulae VIII-1 to VIII-6 are selected from the compounds of the formula VIII-1b to VIII-5b, in particular of the formula VIII-2b:

[0032] in which R1, R2, L, r and s have the meanings defined above. In a third very preferred embodiment, the compounds of the formulae VIII-1 to VIII-6 are selected from the compounds of the formula VIII-1c to VIII-6c, in particular of the formula I3-c: in which R1, R2, L, r and s have the meanings defined above. In a fourth very preferred embodiment, the compounds of the formulae VIII-1 to VIII- 6 are selected from the compounds of the formula VIII-1d to VIII-6d, in particular of the formula VIII-3d: in which R1, R2, L, r and s have the meanings defined above. In a particularly preferred embodiment, the medium according to the invention comprises one or more compounds selected from the group of the formulae VIII-1a to VIII-6a and one or more compounds selected from the group of the formulae VIII- 1b to VIII-6b. Very particularly preferably the medium comprises one or more compounds selected from the group of compounds of the formulae VIII-3a, VIII-2b, VIII-3c and VIII-3d: in which R81, R82, L and r have the meanings defined above and preferably r is 0. Most preferred compounds of formula I include, in particular, one or more of the

[0033] VIII-2b-5

[0034] Alternatively, or additionally, the following compounds of formula I can be used:

[0035] Further preferred embodiments are listed below: a) Liquid-crystalline medium comprising at least one compound of the formulae Z-1 to Z-8,

[0036] in which R has the meanings of the radical R2Aof formula IIA and alkyl denotes n-alkyl having 1 to 7 C atoms. b) Preferred liquid-crystalline media according to the invention comprise one or more substances which contain a tetrahydronaphthyl or naphthyl unit, such as, for example, the compounds of the formulae N-1 to N-5,

[0037] in which R1Nand R2Neach, independently of one another, have the meanings indicated for R2A, preferably denote straight-chain alkyl, straight-chain alkoxy or straight-chain alkenyl, and Z1and Z2each, independently of one another, denote -C2H4-, -CH=CH-, -(CH2)4-, -(CH2)3O-, -O(CH2)3-, -CH=CHCH2CH2-, -CH2CH2CH=CH-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF-, -CF=CH-, -CH=CF-, -CF2O-, -OCF2-, -CH2- or a single bond. c) Preferred mixtures comprise one or more compounds selected from the group of the difluorodibenzochroman compounds of the formula BC, chromans of the formula CR, and fluorinated phenanthrenes of the formulae PH-1 and PH-2, PH-2 in which RB1, RB2, RCR1, RCR2, R1, R2each, independently of one another, have the meaning of R2A. c is 0, 1 or 2. R1and R2preferably, independently of one another, denote alkyl or alkoxy having 1 to 6 C atoms. Particularly preferred compounds of the formulae BC and CR are the compounds BC-1 to BC-7 and CR-1 to CR-5,

[0038] in which alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1 to 6 C atoms, and alkenyl and alkenyl* each, independently of one another, denote a straight- chain alkenyl radical having 2 to 6 C atoms. Very particular preference is given to mixtures comprising one, two or three compounds of the formula BC-2, BF-1 and / or BF-2. d) Preferred mixtures comprise one or more indane compounds of the formula In, in which R11, R12, and R13each, independently of one another, denote a straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl radical having 1 to 6 C atoms, R12and R13alternatively denote halogen, preferably F, i denotes 0, 1 or 2. Preferred compounds of the formula In are the compounds of the formulae In- 1 to In-16 indicated below:

[0039] Particular preference is given to the compounds of the formulae In-1, In-2, In-3 and In-4. e) Preferred mixtures additionally comprise one or more compounds of the formulae L-1 to L-5,

[0040] in which R, R1and R2each, independently of one another, have the meanings indicated for R2Ain formula IIA above, and alkyl denotes an alkyl radical having 1 to 6 C atoms. The parameter s denotes 1 or 2. The compounds of the formulae L-1 to L-9 are preferably employed in concentrations of 5 to 15 % by weight, in particular 5 to 12 % by weight and very particularly preferably 8 to 10 % by weight. f) Preferred mixtures additionally comprise one or more compounds of formula IIA- IIA-Y in which R11and R12have one of the meanings given for R2Ain formula IIA above, and L1and L2, identically or differently, denote F or Cl. Preferred compounds of the formula IIA-Y are selected from the group consisting of the following sub-formulae

[0041] in which, Alkyl and Alkyl* each, independently of one another, denote a straight- chain alkyl radical having 1-6 C atoms, Alkoxy denotes a straight-chain alkoxy radical having 1-6 C atoms, Alkenyl and Alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms, and O denotes an oxygen atom or a single bond. Alkenyl and Alkenyl* preferably denote 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-. Particularly preferred compounds of the formula IIA-Y are selected from the group consisting of following sub-formulae: IIA-Y6a IIA-Y6b in which Alkoxy and Alkoxy* have the meanings defined above and preferably denote methoxy, ethoxy, n-propyloxy, n-butyloxy or n-pentyloxy. The medium according to the invention preferably comprises one or more compounds selected from the group of compounds of the formulae PI and PII in which R2and R3denote H, an alkyl or alkoxy radical having 1 to 12 C atoms, in which one or more CH2groups in these radicals are optionally replaced -CO-O- or -O-CO- in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, preferably alkyl having 1 to 7 C atoms or alkenyl having 2 to 7 C atoms or cyclic alkyl having 3 to 9 C atoms in which one or more H atoms may be replaced by F, and

[0042] L31and L32independently of each other, denote H or F, Y2and Y3identically or differently, denote H or CH3, X2and X3independently of each other, denote halogen, halogenated alkyl or alkoxy with 1 to 3 C-atoms or halogenated alkenyl or alkenyloxy with 2 or 3 C-atoms, preferably F, Cl, CF3, OCF3or OCHF2, more preferably F or OCF3, in particular F, Z3denotes -CH2CH2-, -CF2CF2-, -COO-, trans- -CH=CH-, trans-CF=CF-, -CH2O- or a single bond, and l, m, n and o are, independently of each other, 0 or 1, where the compounds of formula CL are excluded from formula PII. The compounds of formula PI are preferably selected from the group of compounds of formulae PI-1 to PI-3, very preferably from the group of compounds of formulae PI-1 and PI-3, in particular PI-3:

[0043] in which the occurring groups have the respective meanings given under formula PI above and in formula PI-1 the radicals L23and L24denote, independently of each other and of the other parameters, H or F and in formula PI-2 preferably In formulae PI-1, PI-2 and PI-3, L21and L22or L23and L24are preferably both F. In another preferred embodiment in formulae PI-1 and PI-2, all of L21, L22, L23and L24denote F. The compounds of formula PI-1 are preferably selected from the group of compounds of formulae PI-1a to PI-1h

[0044] In a preferred embodiment of the present invention the medium comprises one or more compounds selected from the group of compounds of the formulae PI-1a to PI-1h wherein L21and L22, and / or L23and L24are both F, respectively. In another preferred embodiment the medium comprises one or more compounds selected from the group of compounds of formulae PI-1a to PI-1h, in which L21, L22, L23and L24all denote F. Very preferred compounds of formula PI-1 are in which R2has the meaning given above. Preferably the compounds of formula PI-2 are selected from the group of compounds of formulae PI-2a to PI-2c in which the occurring groups have the respective meanings given above and preferably L21and L22are both F. Preferably the compounds of formula PI-3 are selected from the group of compounds of formulae PI-3a to PI-3e

[0045] in which the occurring groups have the respective meanings given above and preferably L21and L22are both F and L23and L24are both H or L21, L22, L23and L24are all F. Very preferred compounds of formula PI-3 are

[0046] in which R2has the meaning given above. Alternatively, or in addition to the preferred compounds of formula PI above, the medium optionally comprises one or more compounds of formula PI selected from the compounds of the formulae PIA-1 to PIA-7:

[0047] in which R2and X2have the meanings given in formula PI or one of the preferred meanings given above and below. Preferred compounds are those of formula PIA-1, PIA-2 and PIA-3, very preferred those of formula PIA-1 and PIA-2, furthermore PIA-8, PIA-11, PIA-13, PIA-23, PIA- 26 and PIA-27. In the compounds of formulae PIA-1 to PIA-28 R2preferably denotes alkyl having 1 to 6 C atoms, very preferably ethyl or propyl, X2preferably denotes F or OCF3, very preferably F. In another preferred embodiment of the present invention the medium comprises one or more compounds of formula PII preferably selected from the group of formulae PII-1 and PII-2, preferably of formula PII-2: in which the occurring groups and parameters have the respective meanings given under formula PII above. Preferably the compounds of formula PII-1 are selected from the group of compounds of formulae PII-1a and PII-1b in which the occurring groups have the respective meanings given above and L33and L34, independently of each other, denote H or F. The compounds of formula PII-1a are preferably selected from the group of compounds of formulae PII-1a-1 to PII-1a-6 in which R3has the meaning given above. Preferably the compounds of formula PII-2 are selected from the group of compounds of formulae PII-2a to PII-2m in which the occurring groups have the respective meanings given above and L35and L36, independently of one another, denote H or F. Preferably, the compounds of formula PII-2a are selected from the group of compounds of formulae PII-2a-1 to PII-2a-4 in which R3has the meaning given above. The compounds of formula PII-2b are preferably selected from the group of compounds of formulae PII-2b-1 and PII-2b-2, preferably PII-2b-2 in which R3has the meaning given above. The compounds of formula PII-2c are preferably selected from the group of compounds of formulae PII-2c-1 to PII-2c-5 in which R3has the meaning given above. The compounds of formulae PII-2d and PII-2e are preferably selected from the group of compounds of formulae PII-2d-1 and PII-2e-1 PII-2d-1 in which R3has the meaning given above. The compounds of formula PII-2f are preferably selected from the group of compounds of formulae PII-2f-1 to PII-2f-4 The compounds of formula PII-2g are preferably selected from the group of compounds of formulae PII-2g-1 to PII-2g-7 PII-2g-1

[0048] in which R3has the meaning given above. The compounds of formula PII-2h are preferably selected from the group of compounds of formulae PII-2h-1 to PII-2h-5

[0049] in which R3has the meaning given above. The compounds of formula PII-2i are preferably selected from the group of compounds of formulae PII-2i-1 to PII-2i-3 in which R3has the meaning given above. The compounds of formula PII-2j are preferably selected from the group of compounds of formulae PII-2j-1 to PII-2j-3 in which R3has the meaning given above. The compounds of formula PII-2k are preferably selected from the group of compounds of formulae PII-2k-1 to PII-2k-6

[0050] in which R3has the meaning given above. The compounds of formula PII-2l are preferably selected from the group of compounds of formulae PII-2l-1 to PII-2l-6

[0051] in which R3has the meaning given above. The compounds of formula PII-2m are preferably selected from the compounds of formula PII-2m-1 Alternatively, or in addition to the compounds of the formulae PII-1 and / or PII-2 the media according to the present invention optionally comprise one or more compounds of formula PII-3, in which the groups and parameters have the respective meanings given under formula PII above, preferably of formula PII-3a in which the R3has the meaning given above. Preferably, the medium according to the invention comprises a compound selected from the group of compounds of the formulae ST-1 to ST-19, very preferably of the

[0052] in which RSTdenotes H, an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH2groups in these radicals may each be replaced, -O-CO- in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by halogen, each occurrence, identically or differently, denotes , ZSTeach, independently of one another, denote -CO-O-, -O-CO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -(CH2)4-, -CH=CH-, -CH2O-, -C2F4-, -CH2CF2-, -CF2CH2-, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C ^C- or a single bond, L1and L2each, independently of one another, denote F, Cl, CH3, CF3or CHF2, p denotes 0, 1 or 2, q denotes 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, and n denotes 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10. Of the compounds of the formula ST, special preference is given to the compounds of the formulae ST-3 and in particular:

[0053] In the compounds of the formulae ST-3a and ST-3b, n preferably denotes 3. In the compounds of the formula ST-2a, n preferably denotes 7. Very particularly preferred mixtures according to the invention comprise one or more stabilizers from the group of the compounds of the formulae ST-2a-1, ST-3a-1, ST-

[0054] Preferably, the medium comprises one or more compounds of the formula S in which Ar denotes a methylene group or an aromatic hydrocarbon group having 6 to 40 C atoms or a heteroaromatic hydrocarbon group having 4 to 40 C atoms; preferably an aromatic hydrocarbon group having 6 to 40 C atoms; Sp denotes a spacer group; RSdenotes H, alkyl having 1 to 12 C atoms or alkenyl having 2 to 12 C atoms; single bond; RS1, RS2, RS3and RS4, identically or differently, denote alkyl having 1 to 6 C atoms, preferably having 1 to 3 C atoms, very preferably CH3; G denotes H or RSor a group ZS-HA; z is an integer from 1 to 6, and q is 2, 3 or 4, preferably 3 or 4. In formula S, aryl denotes an aromatic or heteroaromatic hydrocarbon group having 4 to 40 C atoms, comprising one, two, three or four aromatic rings including condensed rings that may be linked directly or via an alkylene linking group having 1 to 12 C atoms, in which one or more H atoms are optionally replaced with alkyl or alkoxy having 1 to 6 C atoms or alkenyl having 2 to 6 C atoms, or with CN, CF3or halogen, and in which one or more CH2groups may each, independently of one another, be replaced by -O-, -S-, -NH-, -N(C1-C4-alkyl)-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CH=CH- or -C ^C- in such a way that O or S atoms are not linked directly to one another. Preferred aryl groups are benzene, naphthalene, anthracene, biphenyl, m-terphenyl, p-terphenyl, and (phenylalkyl)benzene in which alkyl is straight chain alkyl having 1 to 12 C atoms. In a preferred embodiment, the medium according to the invention comprises a compound of the formula S in which the parameter q is 3 and G denotes a group ZS-HA. In another preferred embodiment, the medium according to the invention comprises a compound of the formula S in which the parameter q is 4 and G denotes H or RS. The compounds of formula S are preferably selected from the compounds of the

[0055] in which RHhas the meanings given above and preferably denotes H or O., Sp on each occurrence, identically or differently, denotes a spacer group, and W denotes linear or branched, optionally unsaturated alkylene having 1 to 12 C atoms, in which one or more non-adjacent -CH2- groups may be replaced with -O-. Preferred compounds of formula S-1 are selected from the compounds of the formula S-1-1: in which RHhas the meanings given above and preferably denotes H or O., and n isan integer from 0 to 12, preferably 5, 6, 7, 8 or 9, very preferably 7. Preferred compounds of formula S-2 are selected from the compounds of the formula S-2-1:

[0056] in which RHhas the meanings given above and preferably denotes H or O., and n2, on each occurrence identically or differently, preferably identically, is an integer from 1 to 12, preferably 2, 3, 4, 5, or 6, very preferably 3, and RSon each occurrence identically or differently, preferably identically, denotes alkyl having 1 to 6 C atoms, preferably n-butyl. Preferred compounds of formula S-3 are selected from the compounds of the formula S-3-1: in which RHhas the meanings given above and preferably denotes H or O., and n is an integer from 0 to 12, preferably 5, 6, 7, 8 or 9, very preferably 7. The compounds of the formulae S and ST-1 to ST-18 are preferably each present in the liquid-crystal mixtures according to the invention in amounts of 0.005 – 0.5%, based on the mixture. If the mixtures according to the invention comprise two or more compounds from the group of the compounds of the formulae S and ST-1 to ST-18, the concentration correspondingly increases to 0.01 – 1% in the case of two compounds, based on the mixtures. However, the total proportion of the compounds of the formulae S and ST-1 to ST- 18, based on the mixture according to the invention, should not exceed 2%.  The liquid crystal medium according to the invention, herein also referred to as liquid crystal host mixture, is suitable for the use in polymer stabilised displays. To this end, the medium according to the invention optionally comprises one or more polymerisable compounds of formula P P-Sp-A1-(Z1-A2)z-R P in which independently of each other and on each occurrence identically or differently, P denotes a polymerisable group, Sp denotes a spacer group or a single bond, A1, A2denote an aromatic, heteroaromatic, alicyclic or heterocyclic group, preferably having 4 to 25 ring atoms, which may also contain fused rings, and which is unsubstituted, or mono- or polysubstituted by L, Z1denotes -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -OCH2-, -CH2O-, -SCH2-, - CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -(CH2)n1-, -CF2CH2-, -CH2CF2-, -(CF2)n1-, -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C ^C-, -CH=CH-CO-O-, -O-CO-CH=CH-, -CH2-CH2-CO-O-, -O-CO-CH2-CH2-, -CR0R00-, or a single bond, R0, R00denote H or alkyl having 1 to 12 C atoms, R denotes H, L, or P-Sp-, L denotes F, Cl, -CN, P-Sp- or straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH2-groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a manner that O- and / or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by P-Sp-, F or Cl, z is 0, 1, 2 or 3, and n1 is 1, 2, 3 or 4. The term "reliability" as used herein means the quality of the performance of the display during time and with different stress loads, such as light load, temperature, humidity, voltage, and comprises display effects such as image sticking (area and line image sticking), mura, yogore etc. which are known to the skilled person in the field of LC displays. As a standard parameter for categorising the reliability usually the voltage holding ration (VHR) value is used, which is a measure for maintaining a constant electrical voltage in a test display. Among other factors, a high VHR is a prerequisite for a high reliability of the LC medium. Unless indicated otherwise, the term "PSA" is used hereinafter when referring to displays of the polymer sustained alignment type in general, and the term "PS" is used when referring to specific display modes, like PS-VA, PS-TN and the like. As used herein, the terms "active layer" and "switchable layer" mean a layer in an electrooptical display, for example an LC display, that comprises one or more molecules having structural and optical anisotropy, like for example LC molecules, which change their orientation upon an external stimulus like an electric or magnetic field, resulting in a change of the transmission of the layer for polarized or unpolarized light. As used herein, the terms "tilt" and "tilt angle" will be understood to mean a tilted alignment of the LC molecules of an LC medium relative to the surfaces of the cell in an LC display (here preferably a PSA display). The tilt angle here denotes the average angle (< 90°) between the longitudinal molecular axes of the LC molecules (LC director) and the surface of the plane-parallel outer plates which form the LC cell. A low value for the tilt angle (i.e., a large deviation from the 90° angle) corresponds to a large tilt here. A suitable method for measurement of the tilt angle is given in the examples. Unless indicated otherwise, tilt angle values disclosed above and below relate to this measurement method. As used herein, the terms "reactive mesogen" and "RM" will be understood to mean a compound containing a mesogenic or liquid crystalline skeleton, and one or more functional groups attached thereto which are suitable for polymerisation and are also referred to as "polymerisable group" or "P". Unless stated otherwise, the term "polymerisable compound" as used herein will be understood to mean a polymerisable monomeric compound. As used herein, the term "low-molecular-weight compound" will be understood to mean to a compound that is monomeric and / or is not prepared by a polymerisation reaction, as opposed to a "polymeric compound" or a "polymer". As used herein, the term "unpolymerisable compound" will be understood to mean a compound that does not contain a functional group that is suitable for polymerisation under the conditions usually applied for the polymerisation of the RMs. The term "mesogenic group" as used herein is known to the person skilled in the art and described in the literature, and means a group which, due to the anisotropy of its attracting and repelling interactions, essentially contributes to causing a liquid- crystal (LC) phase in low-molecular-weight or polymeric substances. Compounds containing mesogenic groups (mesogenic compounds) do not necessarily have to have an LC phase themselves. It is also possible for mesogenic compounds to exhibit LC phase behaviour only after mixing with other compounds and / or after polymerisation. Typical mesogenic groups are, for example, rigid rod- or disc- shaped units. An overview of the terms and definitions used in connection with mesogenic, or LC compounds is given in Pure Appl. Chem.2001, 73(5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem.2004, 116, 6340-6368. As used herein, the terms “optically active” and “chiral” are synonyms for materials that are able to induce a helical pitch in a nematic host material, also referred to as “chiral dopants”. The term "spacer group", above and below also referred to as "Sp", as used herein is known to the person skilled in the art and is described in the literature, see, for example, Pure Appl. Chem.2001, 73(5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem.2004, 116, 6340-6368. As used herein, the terms "spacer group" or "spacer" mean a flexible group, for example an alkylene group, which connects the mesogenic group and the polymerisable group(s) in a polymerisable mesogenic compound. Likewise, in the compounds of formula I, a spacer group connects a central hydrocarbon group with a photoactive, stabilising hindered amine functional group. Above and below, denotes a trans-1,4-cyclohexylene ring. In a group the single bond shown between the two ring atoms can be attached to any free position of the benzene ring. Above and below "organic group" denotes a carbon or hydrocarbon group. "Carbon group" denotes a mono- or polyvalent organic group containing at least one carbon atom, where this either contains no further atoms (such as, for example, -C ^C-) or optionally contains one or more further atoms, such as, for example, N, O, S, B, P, Si, Se, As, Te or Ge (for example carbonyl, etc.). The term "hydrocarbon group" denotes a carbon group which additionally contains one or more H atoms and optionally one or more heteroatoms, such as, for example, N, O, S, B, P, Si, Se, As, Te or Ge. "Halogen" denotes F, Cl, Br or I, preferably F or Cl. -CO-, -C(=O)- and -C(O)- denote a carbonyl group, i.e., . A carbon or hydrocarbon group can be a saturated or unsaturated group. Unsaturated groups are, for example, aryl, alkenyl or alkynyl groups. A carbon or hydrocarbon radical having more than 3 C atoms can be straight-chain, branched and / or cyclic and may also contain spiro links or condensed rings. The terms "alkyl", "aryl", "heteroaryl", etc., also encompass polyvalent groups, for example alkylene, arylene, heteroarylene, etc. The term "aryl" denotes an aromatic carbon group, or a group derived therefrom. The term "heteroaryl" denotes "aryl" as defined above, containing one or more heteroatoms, preferably selected from N, O, S, Se, Te, Si and Ge. Preferred carbon and hydrocarbon groups are optionally substituted, straight-chain, branched or cyclic, alkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy having 1 to 40, preferably 1 to 20, very preferably 1 to 12, C atoms, optionally substituted aryl or aryloxy having 5 to 30, preferably 6 to 25, C atoms, or optionally substituted alkylaryl, arylalkyl, alkylaryloxy, arylalkyloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy having 5 to 30, preferably 6 to 25, C atoms, wherein one or more C atoms may also be replaced by hetero atoms, preferably selected from N, O, S, Se, Te, Si and Ge. Further preferred carbon and hydrocarbon groups are C1-C20alkyl, C2-C20alkenyl, C2-C20alkynyl, C3-C20allyl, C4-C20alkyldienyl, C4-C20polyenyl, C6-C20cycloalkyl, C4- C15cycloalkenyl, C6-C30aryl, C6-C30alkylaryl, C6-C30arylalkyl, C6-C30alkylaryloxy, C6-C30arylalkyloxy, C2-C30heteroaryl, C2-C30heteroaryloxy. Particular preference is given to C1-C12alkyl, C2-C12alkenyl, C2-C12alkynyl, C6-C25aryl and C2-C25heteroaryl. Further preferred carbon and hydrocarbon groups are straight-chain, branched or cyclic alkyl having 1 to 20, preferably 1 to 12, C atoms, which are unsubstituted or mono- or polysubstituted by F, Cl, Br, I or CN and in which one or more non- adjacent CH2groups may each be replaced, independently of one another, by - C(Rx)=C(Rx)-, -C ^-, -N(Rx)-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that O and / or S atoms are not linked directly to one another. Rxpreferably denotes H, F, Cl, CN, a straight-chain, branched or cyclic alkyl chain having 1 to 25 C atoms, in which, in addition, one or more non-adjacent C atoms may be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- and in which one or more H atoms may be replaced by F or Cl, or denotes an optionally substituted aryl or aryloxy group with 6 to 30 C atoms, or an optionally substituted heteroaryl or heteroaryloxy group with 2 to 30 C atoms. Preferred alkyl groups are, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl, s-pentyl, cyclopentyl, n-hexyl, cyclohexyl, 2-ethylhexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, dodecanyl, trifluoromethyl, perfluoro-n-butyl, 2,2,2- trifluoroethyl, perfluorooctyl, perfluorohexyl, etc. Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, etc. Preferred alkynyl groups are, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, octynyl, etc. Preferred alkoxy groups are, for example, methoxy, ethoxy, 2-methoxyethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy, 2-methylbutoxy, n-pentoxy, n-hexoxy, n-heptoxy, n-octoxy, n-nonoxy, n-decoxy, n-undecoxy, n-dodecoxy, etc. Preferred amino groups are, for example, dimethylamino, methylamino, methylphenylamino, phenylamino, etc. Aryl and heteroaryl groups can be monocyclic or polycyclic, i.e., they can contain one ring (such as, for example, phenyl) or two or more rings, which may also be fused (such as, for example, naphthyl) or covalently bonded (such as, for example, biphenyl), or contain a combination of fused and linked rings. Heteroaryl groups contain one or more heteroatoms, preferably selected from O, N, S and Se. Particular preference is given to mono-, bi- or tricyclic aryl groups having 6 to 25 C atoms and mono-, bi- or tricyclic heteroaryl groups having 5 to 25 ring atoms, which optionally contain fused rings and are optionally substituted. Preference is furthermore given to 5-, 6- or 7-membered aryl and heteroaryl groups, in which, in addition, one or more CH groups may be replaced by N, S or O in such a way that O atoms and / or S atoms are not linked directly to one another. Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl, [1,1':3',1'']terphenyl-2'-yl, naphthyl, anthracene, binaphthyl, phenanthrene, 9,10- dihydro-phenanthrene, pyrene, dihydropyrene, chrysene, perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene, etc. Preferred heteroaryl groups are, for example, 5-membered rings, such as pyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, furan, thiophene, selenophene, oxazole, isoxazole, 1,2-thiazole, 1,3-thiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4- thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 6-membered rings, such as pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, 1,2,4,5- tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine, or condensed groups, such as indole, isoindole, indolizine, indazole, benzimidazole, benzotriazole, purine, naphthimidazole, phenanthrimidazole, pyridimidazole, pyrazinimidazole, quinoxalinimidazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, benzothiazole, benzofuran, isobenzofuran, dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8- quinoline, benzoisoquinoline, acridine, phenothiazine, phenoxazine, benzopyridazine, benzopyrimidine, quinoxaline, phenazine, naphthyridine, aza- carbazole, benzocarboline, phenanthridine, phenanthroline, thieno[2,3b]thiophene, thieno[3,2b]thiophene, dithienothiophene, isobenzothiophene, dibenzothiophene, benzothiophene, benzothiadiazothiophene, or combinations of these groups. The aryl and heteroaryl groups mentioned above and below may also be substituted by alkyl, alkoxy, thioalkyl, fluorine, fluoroalkyl or further aryl or heteroaryl groups. The (non-aromatic) alicyclic and heterocyclic groups encompass both saturated rings, i.e., those containing exclusively single bonds, and also partially unsaturated rings, i.e., those which may also contain multiple bonds. Heterocyclic rings contain one or more heteroatoms, preferably selected from Si, O, N, S and Se. The (non-aromatic) alicyclic and heterocyclic groups can be monocyclic, i.e., contain only one ring (such as, for example, cyclohexane), or polycyclic, i.e., contain a plurality of rings (such as, for example, decahydronaphthalene or bicyclooctane). Particular preference is given to saturated groups. Preference is furthermore given to mono-, bi- or tricyclic groups having 5 to 25 ring atoms, which optionally contain fused rings and are optionally substituted. Preference is furthermore given to 5-, 6-, 7- or 8-membered carbocyclic groups, in which, in addition, one or more C atoms may be replaced by Si and / or one or more CH groups may be replaced by N and / or one or more non-adjacent CH2groups may be replaced by -O- and / or -S-. Preferred alicyclic and heterocyclic groups are, for example, 5-membered groups, such as cyclopentane, tetrahydrofuran, tetrahydrothiophen, pyrrolidine, 6-membered groups, such as cyclohexane, silinane, cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1,3-dioxane, 1,3-dithiane, piperidine, 7-membered groups, such as cycloheptane, and fused groups, such as tetrahydronaphthalene, decahydronaphthalene, indane, bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane- 1,4-diyl, spiro[3.3]heptane-2,6-diyl, octahydro-4,7-methanoindane-2,5-diyl. Preferred substituents are, for example, solubility-promoting groups, such as alkyl or alkoxy, electron-withdrawing groups, such as fluorine, nitro or nitrile, or substituents for increasing the glass transition temperature (Tg) in the polymer, in particular bulky groups, such as, for example, t-butyl or optionally substituted aryl groups. Preferred substituents, hereinafter also referred to as "LS", are, for example, F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, -C(=O)N(Rx)2, -C(=O)Y1, -C(=O)Rx, -N(Rx)2, straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy each having 1 to 25 C atoms, in which one or more H atoms may optionally be replaced by F or Cl, optionally substituted silyl having 1 to 20 Si atoms, or optionally substituted aryl having 6 to 25, preferably 6 to 15, C atoms, wherein Rxdenotes H, F, Cl, CN, or straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH2-groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a manner that O- and / or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F, Cl, P- or P-Sp-, and Y1denotes halogen. "Substituted silyl or aryl" preferably means substituted by halogen, -CN, R0, -OR0, -CO-R0, -CO-O-R0, -O-CO-R0or -O-CO-O-R0, wherein R0denotes H or alkyl with 1 to 20 C atoms. Particularly preferred substituents L are, for example, F, Cl, CN, NO2, CH3, C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5, furthermore phenyl. A1and A2very preferably denote which L has one of the meanings indicated above and r denotes 0, 1, 2, 3 or 4, in particular , The polymerisable group P is a group which is suitable for a polymerisation reaction, such as, for example, free-radical or ionic chain polymerisation, polyaddition or polycondensation, or for a polymer-analogous reaction, for example addition or condensation onto a main polymer chain. Particular preference is given to groups for chain polymerisation, in particular those containing a C=C double bond or -C ^C- triple bond, and groups which are suitable for polymerisation with ring opening, such as, for example, oxetane or epoxide groups. Preferred groups P are selected from the group consisting of , (CH2=CH-CH2)2CH-OCO-, (CH2=CH)2CH-O-, (CH2=CH-CH2)2N-, (CH2=CH-CH2)2N-CO-, HO-CW2W3-, HS-CW2W3-, HW2N-, HO-CW2W3-NH-, CH2=CW1-CO-NH-, CH2=CH-(COO)k1-Phe-(O)k2-, CH2=CH-(CO)k1-Phe-(O)k2-, Phe-CH=CH-, HOOC-, OCN- and W4W5W6Si-, in which W1denotes H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH3, W2and W3each, independently of one another, denote H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W4, W5and W6each, independently of one another, denote Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W7and W8each, independently of one another, denote H, Cl or alkyl having 1 to 5 C atoms, Phe denotes 1,4-phenylene, which is optionally substituted by one or more radicals L as defined above which are other than P-Sp-, k1, k2and k3each, independently of one another, denote 0 or 1, k3preferably denotes 1, and k4denotes an integer from 1 to 10. Very preferred groups P are selected from the group consisting of CW1=CH-CO-(O)k3-, CW1=CH-CO-NH-, CH2=CW1-CO-NH-, CH2=CH-(COO)k1-Phe-(O)k2-, CH2=CH-(CO)k1-Phe-(O)k2-, Phe-CH=CH- and W4W5W6Si-, in which W1denotes H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH3, W2and W3each, independently of one another, denote H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W4, W5and W6each, independently of one another, denote Cl, oxaalkyl or oxa- carbonylalkyl having 1 to 5 C atoms, W7and W8each, independently of one another, denote H, Cl or alkyl having 1 to 5 C atoms, Phe denotes 1,4-phenylene, k1, k2and k3each, independently of one another, denote 0 or 1, k3preferably denotes 1, and k4denotes an integer from 1 to 10. Very particularly preferred groups P are selected from the group consisting of CH2=CW1-CO-O-, in particular CH2=CH-CO-O-, CH2=C(CH3)-CO-O- and CH2=CF- CO-O-, furthermore CH2=CH-O-, (CH2=CH)2CH-O-CO-, (CH2=CH)2CH-O-, Further preferred polymerisable groups P are selected from the group consisting of vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide, most preferably from acrylate and methacrylate. If the spacer group Sp is different from a single bond, it is preferably of the formula Sp"-X", so that the respective radical P-Sp- conforms to the formula R-Sp"-X"-, wherein Sp" denotes linear or branched alkylene having 1 to 20, preferably 1 to 12, C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN and inwhich, in addition, one or more non-adjacent CH2 groups may each be replaced,independently of one another, by -O-, -S-, -NH-, -N(R0)-, -Si(R0R00)-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -S-CO-, -CO-S-, -N(R00)-CO-O-, -O-CO-N(R0)-, -N(R0)-CO-N(R00)-, -CH=CH- or -C ^C- in such a way that O and / or S atoms are not linked directly to one another, X" denotes -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CO-N(R0)-, -N(R0)-CO-, -N(R0)-CO-N(R00)-, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=N-, -N=CH-, -N=N-, -CH=CR0-, -CY2=CY3-, -C ^C-, -CH=CH-CO-O-, -O-CO-CH=CH- or a single bond, R0and R00, each, independently of one another, denote H or alkyl having 1 to 20 C atoms, and Y2and Y3each, independently of one another, denote H, F, Cl or CN. X" is preferably -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR0-, -NR0-CO-, -NR0-CO-NR00- or a single bond. Typical spacer groups Sp and -Sp"-X"- are, for example, -(CH2)p1-, -(CH2)p1-O-, - (CH2)p1-O-CO-, -(CH2)p1-CO-O-, -(CH2)p1-O-CO-O-, -(CH2CH2O)q1-CH2CH2-, - CH2CH2-S-CH2CH2-, -CH2CH2-NH-CH2CH2- or -(SiR0R00-O)p1-, in which p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R0and R00have the meanings indicated above. 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-, in which p1 and q1 have the meanings indicated above. Particularly preferred groups Sp" are, in each case straight-chain, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene, ethenylene, propenylene and butenylene. In a preferred embodiment of the invention the compounds of formula P and its sub- formulae contain a spacer group Sp that is substituted by one or more polymerisable groups P, so that the group Sp-P corresponds to Sp(P)s, with s being ≥2 (branched polymerisable groups). Preferred compounds of formula P according to this preferred embodiment are those wherein s is 2, i.e., compounds which contain a group Sp(P)2. Very preferred compounds of formula P according to this preferred embodiment contain a group selected from the following formulae: -X-alkyl-CHPP S1 -X-alkyl-CH((CH2)aaP)((CH2)bbP) S2 -X-N((CH2)aaP)((CH2)bbP) S3 -X-alkyl-CHP-CH2-CH2P S4 -X-alkyl-C(CH2P)(CH2P)-CaaH2aa+1S5 -X-alkyl-CHP-CH2P S6 -X-alkyl-CPP-CaaH2aa+1S7 -X-alkyl-CHPCHP-CaaH2aa+1S8 in which P is as defined in formula P, alkyl denotes a single bond or straight-chain or branched alkylene having 1 to 12 C atoms which is unsubstituted or mono- or polysubstituted by F, Cl or CN and in which one or more non-adjacent CH2groups may each, independently of one another, be replaced by -C(R0)=C(R0)-, -C ^C-, -N(R0)-, -O-, -S-, -CO-, -CO-O-, -O- CO-, -O-CO-O- in such a way that O and / or S atoms are not linked directly to one another, where R0has the meaning indicated above, aa and bb each, independently of one another, denote 0, 1, 2, 3, 4, 5 or 6, X has one of the meanings indicated for X", and is preferably O, CO, SO2, O-CO-, CO-O or a single bond. Preferred spacer groups Sp(P)2are selected from formulae S1, S2 and S3. Very preferred spacer groups Sp(P)2are selected from the following sub-formulae: -CHPP S1a -O-CHPP S1b -CH2-CHPP S1c -OCH2-CHPP S1d -CH(CH2-P)(CH2-P) S2a -OCH(CH2-P)(CH2-P) S2b -CH2-CH(CH2-P)(CH2-P) S2c -OCH2-CH(CH2-P)(CH2-P) S2d -CO-NH((CH2)2P)((CH2)2P) S3a In the compounds of formula P and its sub-formulae as described above and below, P is preferably selected from the group consisting of vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide, most preferably from acrylate and methacrylate. Further preferred are compounds of formula P and its sub-formulae as described above and below, wherein all polymerisable groups P that are present in the compound have the same meaning, and very preferably denote acrylate or methacrylate, most preferably methacrylate. In the compounds of formula P and its sub-formulae as described above and below, R preferably denotes P-Sp-. Further preferred are compounds of formula P and its sub-formulae as described above and below, wherein Sp denotes a single bond or -(CH2)p1-, -O-(CH2)p1-, -O- CO-(CH2)p1, or -CO-O-(CH2)p1, wherein p1 is 2, 3, 4, 5 or 6, and, if Sp is -O-(CH2)p1-, -O-CO-(CH2)p1or -CO-O-(CH2)p1the O-atom or CO-group, respectively, is linked to the benzene ring. Further preferred are compounds of formula P and its sub-formulae as described above and below, wherein at least one group Sp is a single bond. Further preferred are compounds of formula P and its sub-formulae as described above and below, wherein at least one group Sp is different from a single bond, and is preferably selected from -(CH2)p1-, -O-(CH2)p1-, -O-CO-(CH2)p1, or -CO-O-(CH2)p1, wherein p1 is 2, 3, 4, 5 or 6, and, if Sp is -O-(CH2)p1-, -O-CO-(CH2)p1or -CO-O- (CH2)p1the O-atom or CO-group, respectively, is linked to the benzene ring. Very preferred groups -A1-(Z1-A2)z- in formula P are selected from the following formulae wherein at least one benzene ring is substituted by at last one group L and the benzene rings are optionally further substituted by one or more groups L or P-Sp-. Preferred compounds of formula P and their sub-formulae are selected from the following preferred embodiments, including any combination thereof: - All groups P in the compound have the same meaning, - -A1-(Z-A2)z- is selected from formulae A1, A2 and A5, - the compounds contain exactly two polymerizable groups (represented by the groups P), - the compounds contain exactly three polymerizable groups (represented by the groups P), - P is selected from the group consisting of acrylate, methacrylate and oxetane, very preferably acrylate or methacrylate, - P is methacrylate, - all groups Sp are a single bond, - at least one of the groups Sp is a single bond and at least one of the groups Sp is different from a single bond, - Sp, when being different from a single bond, is -(CH2)p2-, -(CH2)p2-O-, -(CH2)p2-CO-O-, -(CH2)p2-O-CO-, wherein p2 is 2, 3, 4, 5 or 6, and the O- atom or the CO-group, respectively, is connected to the benzene ring, - Sp is a single bond or denotes -(CH2)p2-, -(CH2)p2-O-, -(CH2)p2-CO-O-, -(CH2)p2-O- CO-, wherein p2 is 2, 3, 4, 5 or 6, and the O-atom or the CO-group, respectively, is connected to the benzene ring, - R denotes P-Sp-, - R does not denote or contain a polymerizable group, - R does not denote or contain a polymerizable group and denotes straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH2-groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a manner that O- and / or S- atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F, Cl or La, - L or L’ denote F, Cl or CN, - L is F. Suitable and preferred compounds of formula P are selected from the following formulae: P3

[0057] in which the individual radicals have the following meanings: P1, P2and P3each, independently of one another, denote an acrylate or methacrylate group, Sp1, Sp2and Sp3each, independently of one another, denote a single bond or a spacer group having one of the meanings indicated above and below for Sp, and particularly preferably denote -(CH2)p1-, -(CH2)p1-O-, -(CH2)p1-CO-O-, -(CH2)p1-O-CO- or -(CH2)p1-O-CO-O-, in which p1 is an integer from 1 to 12, where, in addition, one or more of the radicals P1-Sp1-, P2-Sp2- and P3-Sp3- may denote Raa, with the proviso that at least one of the radicals P1-Sp1-, P2- Sp2- and P3-Sp3- present is different from Raa, Raadenotes H, F, Cl, CN or straight-chain or branched alkyl having 1 to 25 C atoms, in which, in addition, one or more non-adjacent CH2groups may each be replaced, independently of one another, by -C(R0)=C(R00)-, -C ^C-, -N(R0)-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that O and / or S atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by F, Cl, CN or P1-Sp1-, particularly preferably straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms (where the alkenyl and alkynyl radicals have at least two C atoms and the branched radicals have at least three C atoms), R0, R00each, independently of one another and identically or differently on each occurrence, denote H or alkyl having 1 to 12 C atoms, Ryand Rzeach, independently of one another, denote H, F, CH3or CF3, X1, X2and X3each, independently of one another, denote -CO-O-, -O-CO- or a single bond, Z1denotes -O-, -CO-, -C(RyRz)- or -CF2CF2-, Z2and Z3each, independently of one another, denote -CO-O-, -O-CO-, -CH2O-, - OCH2-, -CF2O-, -OCF2- or -(CH2)n-, where n is 2, 3 or 4, L on each occurrence, identically or differently, denotes F, Cl, CN or straight- chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms, preferably F, L' and L" each, independently of one another, denote H, F or Cl, k denotes 0 or 1, r denotes 0, 1, 2, 3 or 4, s denotes 0, 1, 2 or 3, t denotes 0, 1 or 2, x denotes 0 or 1. Especially preferred are compounds of the formulae P2, P13, P17, P22, P23, P24, P30, P31 and P32. Further preferred are trireaktive compounds P15 to P30, in particular P17, P18, P19, P22, P23, P24, P25, P26, P30, P31 and P32. In the compounds of formulae P1 to P32 the group

[0058] wherein L on each occurrence, identically or differently, has one of the meanings given above or below, and is preferably F, Cl, CN, CH3, C2H5, C(CH3)3, CH(CH3)2, CH2CH(CH3)C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5or P-Sp-, very preferably F, Cl, CN, CH3, C2H5, OCH3, COCH3, OCF3or P-Sp-, more preferably F, Cl, CH3, OCH3, COCH3oder OCF3, especially F or CH3. Very particularly preferred compounds of the formula P are selected from Table E below, especially selected from the group consisting of formulae 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. For the production of PSA displays, the polymerisable compounds contained in the LC medium are polymerised or crosslinked (if one compound contains two or more polymerisable groups) by in-situ polymerisation in the LC medium between the substrates of the LC display, optionally while a voltage is applied to the electrodes. The structure of the PSA displays according to the invention corresponds to the usual geometry for PSA displays, as described in the prior art cited at the outset. Geometries without protrusions are preferred, in particular those in which, in addition, the electrode on the colour filter side is unstructured and only the electrode on the TFT side has slots. Particularly suitable and preferred electrode structures for PS-VA displays are described, for example, in US 2006 / 0066793 A1. A preferred PSA type LC display of the present invention comprises: - a first substrate including a pixel electrode defining pixel areas, the pixel electrode being connected to a switching element disposed in each pixel area and optionally including a micro-slit pattern, and optionally a first alignment layer disposed on the pixel electrode, - a second substrate including a common electrode layer, which may be disposed on the entire portion of the second substrate facing the first substrate, and optionally a second alignment layer, - an LC layer disposed between the first and second substrates and including an LC medium comprising a polymerisable component comprising one or more compounds of formula R and a liquid crystal host including as described above and below, wherein the polymerisable component may also be polymerised. The first and / or second alignment layer controls the alignment direction of the LC molecules of the LC layer. For example, in PS-VA displays the alignment layer is selected such that it imparts to the LC molecules homeotropic (or vertical) alignment (i.e., perpendicular to the surface) or tilted alignment. Such an alignment layer may for example comprise a polyimide, which may also be rubbed, or may be prepared by a photoalignment method. The LC layer with the LC medium can be deposited between the substrates of the display by methods that are conventionally used by display manufacturers, for example the so-called one-drop-filling (ODF) method. The polymerisable component of the LC medium is then polymerised for example by UV photopolymerisation. The polymerisation can be carried out in one step or in two or more steps. The PSA display may comprise further elements, like a colour filter, a black matrix, a passivation layer, optical retardation layers, transistor elements for addressing the individual pixels, etc., all of which are well known to the person skilled in the art and can be employed without inventive skill. The electrode structure can be designed by the skilled person depending on the individual display type. For example, for PS-VA displays a multi-domain orientation of the LC molecules can be induced by providing electrodes having slits and / or bumps or protrusions in order to create two, four or more different tilt alignment directions. Upon polymerisation the polymerisable compounds form a crosslinked polymer, which causes a certain pretilt of the LC molecules in the LC medium. Without wishing to be bound to a specific theory, it is believed that at least a part of the crosslinked polymer, which is formed by the polymerisable compounds, will phase- separate or precipitate from the LC medium and form a polymer layer on the substrates or electrodes, or the alignment layer provided thereon. Microscopic measurement data (like SEM and AFM) have confirmed that at least a part of the formed polymer accumulates at the LC / substrate interface. The polymerisation can be carried out in one step. It is also possible firstly to carry out the polymerisation, optionally while applying a voltage, in a first step in order to produce a pretilt angle, and subsequently, in a second polymerisation step without an applied voltage, to polymerise or crosslink the compounds which have not reacted in the first step ("end curing"). Suitable and preferred polymerisation methods are, for example, thermal or photopolymerisation, preferably photopolymerisation, in particular UV induced photopolymerisation, which can be achieved by exposure of the polymerisable compounds to UV radiation. Optionally one or more polymerisation initiators are added to the LC medium. Suitable conditions for the polymerisation and suitable types and amounts of initiators are known to the person skilled in the art and are described in the literature. Suitable for free-radical polymerisation are, for example, the commercially available photoinitiators Irgacure651®, Irgacure184®, Irgacure907®, Irgacure369® or Darocure1173® (Ciba AG). If a polymerisation initiator is employed, its proportion is preferably 0.001 to 5% by weight, particularly preferably 0.001 to 1% by weight. The polymerisable compounds according to the invention are also suitable for polymerisation without an initiator, which is accompanied by considerable advantages, such, for example, lower material costs and in particular less contamination of the LC medium by possible residual amounts of the initiator or degradation products thereof. The polymerisation can thus also be carried out without the addition of an initiator. In a preferred embodiment, the LC medium thus does not contain a polymerisation initiator. The LC medium may also comprise one or more stabilisers in order to prevent undesired spontaneous polymerisation of the RMs, for example during storage or transport. Suitable types and amounts of stabilisers are known to the person skilled in the art and are described in the literature. Particularly suitable are, for example, the commercially available stabilisers from the Irganox® series (Ciba AG), such as, for example, Irganox® 1076. If stabilisers are employed, their proportion, based on the total amount of RMs or the polymerisable component (component P), is preferably 10-500,000 ppm, particularly preferably 50-50,000 ppm. The polymerisable compounds of formula P in particular show good UV absorption in, and are therefore especially suitable for, a process of preparing a PSA display including one or more of the following features: - the polymerisable medium is exposed to UV light in the display in a 2-step process, including a first UV exposure step ("UV-1 step") to generate the tilt angle, and a second UV exposure step ("UV-2 step") to finish polymerization, - the polymerisable medium is exposed to UV light in the display generated by an energy-saving UV lamp (also known as “green UV lamps”). These lamps are characterized by a relative low intensity (1 / 100-1 / 10 of a conventional UV1 lamp) in their absorption spectra from 300-380nm, and are preferably used in the UV2 step, but are optionally also used in the UV1 step when avoiding high intensity is necessary for the process. - the polymerisable medium is exposed to UV light in the display generated by a UV lamp with a radiation spectrum that is shifted to longer wavelengths, preferably 340nm or more, to avoid short UV light exposure in the PS-VA process. Both using lower intensity and a UV shift to longer wavelengths protect the organic layer against damage that may be caused by the UV light. A preferred embodiment of the present invention relates to a process for preparing a PSA display as described above and below, comprising one or more of the following features: - the polymerisable LC medium is exposed to UV light in a 2-step process, including a first UV exposure step ("UV-1 step") to generate the tilt angle, and a second UV exposure step ("UV-2 step") to finish polymerization, - the polymerisable LC medium is exposed to UV light generated by a UV lamp having an intensity of from 0.5 mW / cm2to 10 mW / cm2in the wavelength range from 300-380nm, preferably used in the UV2 step, and optionally also in the UV1 step, - the polymerisable LC medium is exposed to UV light having a wavelength of 340 nm or more, and preferably 400 nm or less. This preferred process can be carried out for example by using the desired UV lamps or by using a band pass filter and / or a cut-off filter, which are substantially transmissive for UV light with the respective desired wavelength(s) and are substantially blocking light with the respective undesired wavelengths. For example, when irradiation with UV light of wavelengths ^ of 300-400nm is desired, UV exposure can be carried out using a wide band pass filter being substantially transmissive for wavelengths 300nm < ^ < 400nm. When irradiation with UV light of wavelength ^ of more than 340 nm is desired, UV exposure can be carried out using a cut-off filter being substantially transmissive for wavelengths ^ > 340 nm. "Substantially transmissive" means that the filter transmits a substantial part, preferably at least 50% of the intensity, of incident light of the desired wavelength(s). "Substantially blocking" means that the filter does not transmit a substantial part, preferably at least 50% of the intensity, of incident light of the undesired wavelengths. "Desired (undesired) wavelength" e.g., in case of a band pass filter means the wavelengths inside (outside) the given range of ^, and in case of a cut-off filter means the wavelengths above (below) the given value of ^. This preferred process enables the manufacture of displays by using longer UV wavelengths, thereby reducing or even avoiding the hazardous and damaging effects of short UV light components. UV radiation energy is in general from 6 to 100 J, depending on the production process conditions. Preferably the LC medium according to the present invention essentially consist of a polymerisable component P) comprising or one or more polymerisable compounds of formula P, and an LC host mixture, and an optically active component comprising one or more chiral dopants, as described above and below. However, the LC medium may additionally comprise one or more further components or additives, preferably selected from the list including but not limited to co-monomers, polymerisation initiators, inhibitors, stabilizers, surfactants, wetting agents, lubricating agents, dispersing agents, hydrophobing agents, adhesive agents, flow improvers, defoaming agents, deaerators, diluents, reactive diluents, auxiliaries, colourants, dyes, pigments and nanoparticles. Particular preference is given to LC media comprising one, two or three polymerisable compounds of formula P. Preferably the proportion of compounds of formula P in the LC medium is from >0 to < 5%, very preferably from >0 to < 1%, most preferably from 0.01 to 0.5%. In a preferred embodiment, the medium according to the invention preferably comprises one or more compounds of formula S in a total concentration in the range of from 10 ppm to 2000 ppm, more preferably from 100 ppm to 1000 ppm, still more preferably from 150 ppm to 500 ppm, very preferably from 200 ppm to 400 ppm and in particular from 250 to 300 ppm. In another preferred embodiment, the medium according to the invention preferably comprises one or more compounds of formula S in a total concentration in the range of from 1000 ppm to 5000 ppm, more preferably from more than 1000 ppm to 5000 ppm, still more preferably from 1200 ppm to 4500 ppm, very preferably from 2000 ppm to 4000 ppm and in particular from 2500 to 3500 ppm. The medium according to the invention preferably has negative dielectric anisotropy. The medium according to the invention comprises one or more compounds of the formula I preferably in a total concentration in the range of from > 0% to 20%, preferably from 1% to 15%, more preferably from 2% to 13%, very preferably from 3% to 12%. In a preferred embodiment of the present invention, the medium comprises one or more compounds of the formula IIA in a total concentration in the range of from 0% to 5%, i.e. the concentration of said compounds is below 5% or the medium does not contain one or more compounds of the formula IIA. In another preferred embodiment of the present invention, the medium comprises one or more compounds selected from the compounds of the formulae IIA-10 and IIA-16 in a total concentration in the range of from 0% to 8%. The medium according to the invention preferably comprises - one or more compounds selected from the group of compounds of the formulae IIA, IIB, IIC and IID, or of the formulae IIB, IIC and IID in a total concentration in the range of from 9% to 70%, more preferably from 10% to 65% and very preferably from 20% to 60%, in particular from 25% to 42%; and / or - one or more compounds selected from the group of compounds of the formulae IIB, IIC, IID and in addition one or more compounds of the formula VI-1-4 in a total concentration in the range of from 15% to 75%, more preferably from 19% to 70% and very preferably from 25% to 64%, in particular from 30% to 48%; and / or - one or more compounds selected from the group of compounds of the formulae IIB, IIC, IID and in addition one or more compounds of the formula III and in addition one or more compounds of the formula VI-1-4 in a total concentration in the range of from 25% to 85%, more preferably from 29% to 80% and very preferably from 35% to 74%, in particular from 40% to 60%; and / or - 0% to 8% in total of one or more compounds of the formula IIA, preferably 0% to 5%, or less than 8% in total of one or more compounds of the formula IIA, more preferably less than 5%, very preferably less than 1%; or - 0% to 1% of one or more compounds of formula IIA, very preferably 0%; and / or - one or more compounds of the formula IIB, preferably of the formula IIB-2 and / or IIB-10, more preferably of the formula IIB-2 and IIB-10, in a total concentration in the range of from 10% to 45%, more preferably from 12% to 40%, still more preferably from 15% to 35%, in particular from 17% to 32%; and / or - one or more compounds of the formula IIC, preferably in a total concentration in the range of from 0% to 15%, more preferably from 0.5% to 14% and very preferably from 2% to 12%, in particular from 4% to 10%; and / or - one or more compounds of the formula IID and , preferably of the formula IID-4 preferably in a total concentration in the range of from 0.5% to 15%, more preferably from 1% to 12% and very preferably from 1.5% to 10%; and / or - one or more compounds of the formulae IIB and IID, in a total concentration in the range of from 15% to 50%, more preferably from 18% to 48% and very preferably from 20% to 40%; and / or - one or more compounds of the formula III, preferably of the formula III-2, more preferably of the formula III-2-6, preferably in a total concentration in the range of from 3% to 20%, more preferably from 5% to 17% and very preferably from 6% to 15%; and / or one or more compounds of the formula III-3, preferably in a total concentration in the range of from 0.5% to 10%, more preferably from 1% to 8% and very preferably from 2% to 6%; and / or one or more compounds of the formula IID-4 and III-3; and / or - one or more compounds selected from the formulae IIC and VI-1-4, preferably in in a total concentration in the range of from 1% to 15%, more preferably from 2% to 12% and very preferably from 3% to 10%; and / or - one or more compounds of the formula IV, more preferably of the formula IV-3, in a total concentration in the range of from 20% to 65%, more preferably from 25% to 58%, still more preferably from 28% to 55% and very preferably from 30% to 50%, in particular from 33% to 45%; and / or - one or more compounds of the formula IV-1, preferably in a total concentration in the range of from 1% to 15%, more preferably from 2% to 12%, still more preferably from 3% to 10% and very preferably from 3% to 8%; and / or - one or more compounds of the formula IV-2, preferably in a total concentration in the range of from 0.2% to 5%, more preferably from 0.5% to 3%, still more preferably from 1% to 2%; and / or - one or more compounds of the formula V, more preferably of the formula V-5 and / or V-6, in a total concentration in the range of from 0.1% to 15%, more preferably from 0.2% to 10%, still more preferably from 0.5% to 5% and very preferably from 1% to 2%; and / or one or more compounds of the formula IIA-Y, preferably of the formula IIA-Y6, in a total concentration in the range of from 0.5% to 15%, more preferably from 1% to 10%, and very preferably from 2% to 9%; and / or one or more compounds of the formula CL-3, preferably selected form the compounds CLP-V-m, CLP-V-Om, CLP-n-m, and CLP-n-Om, in which n and m independently are 1, 2, 34 or 5, preferably in a total concentration in the range of from 1% to 12%, more preferably from 2% to 10% and very preferably from 3% to 7%, and / or one or more compounds of the formula PII-2c-3, in particular the compound PII-2c-3 in which R3denotes vinyl (CCG-V-F). It is advantageous for the liquid-crystalline medium according to the invention to preferably have a nematic phase from ^ -20°C to ^ 70°C, particularly preferably from ^ -30°C to ^ 72°C, very particularly preferably from ^ -40°C to ^ 74°C. In a first preferred embodiment, the medium according to the invention has a clearing temperature of 70°C or more, preferably of 72°C or more, more preferably of 73°C or more and in particular of 74°C or more. The expression "have a nematic phase" herein means on the one hand that no smectic phase and no crystallisation are observed at low temperatures at the corresponding temperature and on the other hand that clearing (phase transition to the isotropic phase) still does not occur on heating from the nematic phase. The investigation at low temperatures is carried out in a flow viscometer at the corresponding temperature and checked by storage in test cells having a layer thickness corresponding to the electro-optical use for at least 100 hours. If the stor- age stability at a temperature of -20°C in a corresponding test cell is 1000 h or more, the medium is referred to as stable at this temperature. At temperatures of -30°C and -40°C, the corresponding times are 500 h and 250 h respectively. At high temperatures, the clearing point is measured by conventional methods in capillaries. The liquid-crystal mixture preferably has a flow viscosity ^20of at most 30 mm2^ s-1at 20°C. The liquid crystal mixture according to the invention is nematic, preferably at a temperature of -20°C or less, preferably at -30°C or less, very preferably at -40°C or less. In a preferred embodiment of the present invention, the medium has a birefringence of 0.125 or more, or in the range of from 0.125 to 0.160, more preferably from 0.126 to 0.155, very preferably from 0.127 to 0.145 and in particular from 0.130 to 0.138. In another preferred embodiment, the medium has a birefringence of 0.103 or less, or in the range of from 0.085 to 0.102, more preferably from 0.090 to 0.102, very preferably from 0.091 to 0.101 and in particular from 0.092 to 0.100. In a preferred embodiment, the liquid-crystal mixture according to the invention has a dielectric anisotropy ^ ^ of -2.5 to -6.0, preferably of -2.8 to –5.0 , in particular -3.0 to -4.5. The rotational viscosity ^1at 20°C is preferably in the range of from 60 to 120 mPas, more preferably from 80 to 110 mPa s. The elastic constant K1is preferably in the range of from 12.0 to 19.0, more preferably from 13.0 to 16.0, in particular from 14.0 to 15.5. The elastic constant K3is preferably in the range of from 12.0 to 19.0, more preferably from 13.0 to 15.0, in particular from 13.5 to 15.5. In addition, the liquid-crystal media according to the invention have high values for the voltage holding ratio in liquid-crystal cells. In general, liquid-crystal media having a low addressing voltage or threshold voltage exhibit a lower voltage holding ratio than those having a higher addressing voltage or threshold voltage and vice versa. For the present invention, the term "dielectrically positive compounds" denotes compounds having a ^ ^ > 1.5, the term "dielectrically neutral compounds" denotes those having -1.5 ^ ^ ^ ^ 1.5 and the term "dielectrically negative compounds” denotes those having ^ ^ < -1.5. The dielectric anisotropy of the compounds is determined here by dissolving 10 % of the compounds in a liquid-crystalline host and determining the capacitance of the resultant mixture in at least one test cell in each case having a layer thickness of 20 µm with homeotropic and with homogeneous surface alignment at 1 kHz. The measurement voltage is typically 0.5 V to 1.0 V but is always lower than the capacitive threshold of the respective liquid- crystal mixture investigated. All temperature values indicated for the present invention are in °C. The mixtures according to the invention are suitable for all VA-TFT applications, such as, for example, VAN, MVA, (S)-PVA, ASV, PSA (polymer sustained VA) and PS-VA (polymer stabilized VA). They are furthermore suitable for IPS (in-plane switching) and FFS (fringe field switching) applications having negative ^ ^, in particular UB-FFS. It goes without saying for the person skilled in the art that the VA, IPS or FFS mixture according to the invention may also comprise compounds in which, for example, H, N, O, Cl and F have been replaced by the corresponding isotopes. The compounds according to the present invention can be synthesized by or in analogy to known methods described in the literature (for example in the standard works such as Houben-Weyl, Methoden der Organischen Chemie [Methods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart), under reaction conditions which are known and suitable for said reactions. Use may also be made here of variants which are known per se but are not mentioned here. In particular, they can be prepared as described in or in analogy to the following reaction schemes. Further methods for preparing the inventive compounds can be taken from the examples. Other mesogenic compounds which are not explicitly mentioned above can optionally and advantageously also be used in the media in accordance with the present invention. Such compounds are known to the person skilled in the art. For the present invention and in the following examples, the structures of the liquid- crystal compounds are indicated by means of acronyms, with the transformation into chemical formulae taking place in accordance with Tables A to C below. All radicals CmH2m+1, CnH2n+1, and ClH2l+1or CmH2m-1, CnH2n-1and ClH2l-1are straight-chain alkyl radicals or alkylene radicals, in each case having n, m and l C atoms respectively. Preferably n, m and l are independently of each other 1, 2, 3, 4, 5, 6, or 7. Table A shows the codes for the ring elements of the nuclei of the compound, Table B lists the bridging units, and Table C lists the meanings of the symbols for the left- and right-hand end groups of the molecules. The acronyms are composed of the codes for the ring elements with optional linking groups, followed by a first hyphen and the codes for the left-hand end group, and a second hyphen and the codes for the right- hand end group. Table D shows illustrative structures of compounds together with their respective abbreviations. Table A: Ring elements

[0059] Table B: Bridging units E -CH2-CH2- V -CH=CH- T -C≡C- W -CF2-CF2- B -CF=CF- Z -CO-O- -O-CO- X -CF=CH- -CH=CF- O -CH2-O- -O-CH2- -O-CF2- T On the left individually or in combi- On the right individually or in com- nation bination -n- CnH2n+1- -n -CnH2n+1-nO- CnH2n+1-O- -On -O- CnH2n+1-V- CH2=CH- -V -CH=CH2-nV- CnH2n+1-CH=CH- -nV -CnH2n-CH=CH2-Vn- CH2=CH- CnH2n- -Vn -CH=CH-CnH2n+1-nVm- CnH2n+1-CH=CH-CmH2m- -nVm - CnH2n-CH=CH-CmH2m+1-N- N≡C- -N -C≡N -S- S=C=N- -S -N=C=S -F- F- -F -CL- Cl- -CL -Cl -M- CFH2- -M -CFH2-D- CF2H- -D -CF2H -T- CF3- -T -CF3-MO- CFH2O - -OM -OCFH2-DO- CF2HO - -OD -OCF2H -TO- CF3O - -OT -OCF3-A- H-C≡C- -A -C≡C-H -nA- CnH2n+1-C≡C- -An -C≡C-CnH2n+1-NA- N≡C-C≡C- -AN -C≡C-C≡N On the left only in combination On the right only in combination -…n…- -CnH2n- -…M…- -CFH- -…M… -CFH- -…D…- -CF2- -…D… -CF2- -…V…- -CH=CH- -…V… -CH=CH- -…Z…- -CO-O- -…Z… -CO-O- -…ZI…- -O-CO- -…ZI… -O-CO- -…K…- -CO- -…K… -CO- -…W…- -CF=CF- -…W… -CF=CF- in which n and m are each integers, and the three dots "…" are placeholders for other abbreviations from this table. Apart from the compounds of formula I, IIA, IIB, IIC and / or IID, IVa, IVb and V, the mixtures according to the invention optionally comprise one or more compounds of the compounds mentioned below. The following abbreviations are used: (n, m, k and l are, independently of one another, each an integer, preferably 1 to 9 preferably 1 to 7, k and l possibly may be also 0 and preferably are 0 to 4, more preferably 0 or 2 and most preferably 2, n preferably is 1, 2, 3, 4 or 5, in the combination “-nO-” it preferably is 1, 2, 3 or 4, preferably 2 or 4, m preferably is 1, 2, 3, 4 or 5, in the combination “-Om” it preferably is 1, 2, 3 or 4, more preferably 2 or 4. The combination “-lVm” preferably is “2V1”.) Table D CC-n-Om

[0060] CC-V-Vm CP-n-m CCP-V-m CCG-V-F CnH2n+1-CH=CH CmH2m+1CCP-nV-m CCVC-n-m

[0061] CPG-n-m SGP-m-n CPGP-n-m

[0062] CY-nVl-m

[0063] PY-Vl-m

[0064] CCY-nV-Om

[0065] CY-n-Om

[0066] Y-n-Om

[0067] CAIY-n-Om

[0068] CCOY-n-Om

[0069] PYP-n-lV

[0070] CLY-n-m

[0071] B(S)-(c3)nO-Om

[0072] B(S)-mVnO-Op(c5) Table E Table E shows illustrative reactive mesogenic compounds which can be used in the LC media in accordance with the present invention. RM-3 RM-4

[0073] RM-39 RM-40

[0074] RM-50

[0075] RM-86 RM-87

[0076] RM-96 RM-97

[0077] RM-103

[0078] RM-125 RM-126 RM-143 RM-144 RM-153 RM-154

[0079] RM-163 RM-164 RM-175 RM-176 In a preferred embodiment, the mixtures according to the invention comprise one or more polymerizable compounds, preferably selected from the polymerizable compounds of the formulae RM-1 to RM-182. Of these, 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. The present invention is illustrated in detail by the following non-restrictive working examples. The following abbreviations and symbols are used: V0threshold voltage, capacitive [V] at 20°C, neextraordinary refractive index at 20°C and 589 nm, noordinary refractive index at 20°C and 589 nm, ^n optical anisotropy at 20°C and 589 nm, ^^dielectric permittivity perpendicular to the director at 20°C and 1 kHz, ^^ ^dielectric permittivity parallel to the director at 20°C and 1 kHz, ^ ^ dielectric anisotropy at 20°C and 1 kHz, cl.p., T(N,I) clearing point [°C], ^1rotational viscosity at 20°C [mPa ^s], K1elastic constant, "splay" deformation at 20°C [pN], K2elastic constant, "twist" deformation at 20°C [pN], K3elastic constant, "bend" deformation at 20°C [pN]. Kavdenotes the average elastic constant defined as Kav =(1.5K1+K3) at 20°C [pN], and LTS denotes low-temperature stability (nematic phase), determined in test cells or in the bulk, as specified. Unless explicitly noted otherwise, all concentrations in the present application are quoted in per cent by weight and relate to the corresponding mixture as a whole, comprising all solid or liquid-crystalline components, without solvents. Unless explicitly noted otherwise, all temperature values indicated in the present application, such as, for example, for the melting point T(C,N), the transition from the smectic (S) to the nematic (N) phase T(S,N) and the clearing point T(N,I), are quoted in degrees Celsius (°C). M.p. denotes melting point, cl.p. = clearing point. Furthermore, C = crystalline state, N = nematic phase, S = smectic phase and I = isotropic phase. The data between these symbols represent the transition temperatures. All physical properties are and have been determined in accordance with "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status Nov.1997, Merck KGaA, Germany, and apply for a temperature of 20°C, and ^n is determined at 589 nm and ^ ^ at 1 kHz, unless explicitly indicated otherwise in each case. The term "threshold voltage" for the present invention relates to the capacitive threshold (V0), also known as the Freedericks threshold, unless explicitly indicated otherwise. In the examples, the optical threshold may also, as generally usual, be quoted for 10% relative contrast (V10). Unless stated otherwise, the process of polymerising the polymerisable compounds in the PSA displays as described above and below is carried out at a temperature where the LC medium exhibits a liquid crystal phase, preferably a nematic phase, and most preferably is carried out at room temperature. Unless stated otherwise, methods of preparing test cells and measuring their electrooptical and other properties are carried out by the methods as described hereinafter or in analogy thereto. The display used for measurement of the capacitive threshold voltage consists of two plane-parallel glass outer plates with a distance of 25 µm, each of which has on the inside an electrode layer and an unrubbed polyimide alignment layer on top, which effect homeotropic alignment of the liquid-crystal molecules. The display or test cell used for measurement of the tilt angles consists of two plane-parallel glass outer plates at a separation of 4 µm, each of which has on the inside an electrode layer and a polyimide alignment layer on top, where the two polyimide layers are rubbed antiparallel to one another and effect a homeotropic edge alignment of the liquid-crystal molecules. The polymerisable compounds are polymerised in the display or test cell by irradiation with UV light of defined intensity for a prespecified time, with a voltage simultaneously being applied to the display (usually 10 V to 30 V alternating current, 1 kHz). In the examples, unless indicated otherwise, a fluorescent lamp and an intensity of 0 to 20 mW / cm² is used for polymerisation. The intensity is measured using a standard meter (Ushio Accumulate UV meter with central wavelength of 313nm). The transmission measurements are performed in test cells with fishbone electrode layout (from Merck Ltd., Japan; 1 pixel fishbone electrode (ITO, 10x10 mm, 47.7° angle of fishbone with 3µm line / 3µm space), 3.2 µm cell gap, AF-glass, tilt angle 1°). The storage stability in the bulk (LTSbulk) of the media according to the invention at a given temperature T is determined by visual inspection.2 g of the media of interest are filled into a closed glass vessel (bottle) of appropriate size placed in a refrigerator at a predetermined temperature. The bottles are checked at defined time intervals for the occurrence of smectic phases or crystallisation. For every material and at each temperature two bottles are stored. If crystallisation or the appearance of a smectic phase is observed in at least one of the two correspondent bottles the test is terminated and the time of the last inspection before the one at which the occurrence of a higher ordered phase is observed is recorded as the respective storage stability. Mixture Examples The Mixture Examples M1 to M20 and P1 to P9 have the compositions and physical properties indicated in the following tables: Comparative Example C1 PY-3-O2 15.0 % Cl.p. [°C]: 75.0CLY-3-O25.5 % ^n [589 nm, 20°C]: 0.1315CPY-2-O2 9.0 % ne[589 nm, 20°C]: 1.6235 CPY-3-O2 9.0 % no[589 nm, 20°C]: 1.4920B(S)-2O-O43.0 % ^ ^ [1 kHz, 20°C]: -4.0B(S)-2O-O5 4.0 %^ ^ ^ [1 kHz, 20°C]:3.8B(S)-2O-O63.0 % ^ ^ [1 kHz, 20°C]: 7.8PGIY-2-O4 6.0 %^1 [mPa s, 20°C]:99PYP-2-3 5.0 % K1[pN, 20°C]: 14.4 CC-3-V 33.0 % K3[pN, 20°C]: 14.5 CC-3-V1 5.0 % CPP-3-2 2.5 %^100.0 %Mixture Example M1 B(S)-2O-O4 3.0 % Cl.p. [°C]: 75.0B(S)-2O-O54.0 % ^n [589 nm, 20°C]: 0.1308B(S)-2O-O6 3.0 % ne[589 nm, 20°C]: 1.6210 CC-3-V 36.0 % no[589 nm, 20°C]: 1.4902CC-3-V1 6.0 %^ ^ [1 kHz, 20°C]:-4.2CLY-3-O2 9.0 % ^^ ^[1 kHz, 20°C]: 3.9CPY-2-O21.5 % ^ ^ [1 kHz, 20°C]: 8.1CPY-3-O2 9.0 % ^1[mPa s, 20°C]: 95 PGIY-2-O4 6.0 % K1[pN, 20°C]: 15.3 PY-3-O2 12.5 % K3[pN, 20°C]: 13.7 YSY-4-O2 10.0 %^ 100.0 %In the following table, key parameters of the mixtures C1 and M1 are summarized. Mixture Example M1 differs from Comparative Example C1 in the presence of a compound YSY-4-O2 of formula I. By use of the compound of formula I, it is surprisingly found that a favorably lower rotational viscosity ( ^1) and at the same time a very low ratio ^1 / K1can be achieved in combination with a higher dielectric anisotropy, which improves the response time of a display. Mixture Example M2 B(S)-2O-O4 3.0 % Cl.p. [°C]: 75.0 B(S)-2O-O5 4.0 % ^n [589 nm, 20°C]: 0.1314 B(S)-2O-O6 3.0 % ne[589 nm, 20°C]: 1.6224 CC-3-V 38.0 % no[589 nm, 20°C]: 1.4910CC-3-V13.0 % ^ ^ [1 kHz, 20°C]: -4.2CLY-3-O2 9.0 % ^^ ^[1 kHz, 20°C]: 4.0CPY-2-O22.5 % ^ ^ [1 kHz, 20°C]: 8.2CPY-3-O2 9.0 %^1 [mPa s, 20°C]:95PGIY-2-O4 6.0 % K1[pN, 20°C]: 14.9 PY-3-O2 12.5 % K3[pN, 20°C]: 13.5 YSY-4-O2 10.0 % ^ 100.0 % Mixture Example M3 B(S)-2O-O4 3.0 % Cl.p. [°C]: 74.0 B(S)-2O-O5 4.0 % ^n [589 nm, 20°C]: 0.1302 B(S)-2O-O6 3.0 % ne[589 nm, 20°C]: 1.6212 CPP-3-2 2.5 % no[589 nm, 20°C]: 1.4910 CC-3-V 33.5 % ^ ^ [1 kHz, 20°C]: -4.1CC-3-V16.0 % ^ ^ ^ [1 kHz, 20°C]: 3.9CLY-3-O2 6.0 % ^^[1 kHz, 20°C]: 8.0CPY-2-O26.5 % ^1 [mPa s, 20°C]: 98CPY-3-O2 9.0 % K1[pN, 20°C]: 14.7 PGIY-2-O4 6.0 % K3[pN, 20°C]: 13.9 PY-3-O2 15.0 % YSY-4-O2 5.5 % ^ 100.0 % Mixture Example M4 B(S)-2O-O4 4.0 % Cl.p. [°C]: 74.5 B(S)-2O-O5 5.0 % ^n [589 nm, 20°C]: 0.1365 B(S)-2O-O6 3.0 % ne[589 nm, 20°C]: 1.6324 CC-3-V 28.5 % no[589 nm, 20°C]: 1.4959CC-3-V17.5 % ^ ^ [1 kHz, 20°C]: -3.2CCP-V-1 7.5 %^ ^ ^ [1 kHz, 20°C]:3.7CCY-3-O2 3.0 % ^^[1 kHz, 20°C]: 6.8CPY-3-O210.0 % ^1 [mPa s, 20°C]: 86PP-1-2V1 7.0 % K1[pN, 20°C]: 15.3 PY-1-O2 7.0 % K3[pN, 20°C]: 15.1 PY-3-O2 3.0 % PYP-2-3 8.0 % CLY-3-O2 1.5 % YSY-4-O2 5.5 %^100.0 %Mixture Example M5 B(S)-2O-O4 3.0 % Cl.p. [°C]: 75.5 B(S)-2O-O5 4.0 % ne[589 nm, 20°C]: 1.6235 B(S)-2O-O6 3.0 % no[589 nm, 20°C]: 1.4918CPP-3-2 2.5 %^n [589 nm, 20°C]:0.1317CC-3-V33.5 % ^ ^ ^ [1 kHz, 20°C]: 3.9CC-3-V1 6.0 %^ ^ [1 kHz, 20°C]:8.0CLY-3-O2 6.0 % ^ ^ [1 kHz, 20°C]: -4.1CPY-2-O26.5 % ^1 [mPa s, 20°C]: 97CPY-3-O2 9.0 % K1[pN, 20°C]: 15.1 PGIY-2-O4 6.0 % K3[pN, 20°C]: 14.3 PY-3-O2 15.0 % YSY-4-O2 2.5 % SPY-3-O2 3.0 % 100.0 % Mixture Example M6 B(S)-2O-O4 3.0 % Cl.p. [°C]: 70.5 B(S)-2O-O5 4.0 % ne[589 nm, 20°C]: 1.6194 B(S)-2O-O6 3.0 % no[589 nm, 20°C]: 1.4914CPP-3-22.5 % ^n [589 nm, 20°C]: 0.1280CC-3-V 33.5 %^ ^ ^ [1 kHz, 20°C]:3.9CC-3-V1 6.0 % ^^[1 kHz, 20°C]: 8.0CLY-3-O26.0 % ^ ^ [1 kHz, 20°C]: -4.1CPY-2-O2 6.5 % ^1[mPa s, 20°C]: 92 CPY-3-O2 9.0 % K1[pN, 20°C]: 14.2 PGIY-2-O4 6.0 % K3[pN, 20°C]: 13.8 PY-3-O2 15.0 % YSY-4-O2 2.5 % SY-1-O2 3.0 % ^ 100.0 % Mixture Example M7 B(S)-2O-O4 3.0 % Cl.p. [°C]: 71 B(S)-2O-O5 4.0 % ne[589 nm, 20°C]: 1.6184 B(S)-2O-O6 3.0 % no[589 nm, 20°C]: 1.4911CPP-3-22.5 % ^n [589 nm, 20°C]: 0.1273CC-3-V 33.5 %^ ^ ^ [1 kHz, 20°C]:3.9CC-3-V1 6.0 % ^^[1 kHz, 20°C]: 8.0CLY-3-O26.0 % ^ ^ [1 kHz, 20°C]: -4.1CPY-2-O2 6.5 % ^1[mPa s, 20°C]: 92 CPY-3-O2 9.0 % K1[pN, 20°C]: 14.1 PGIY-2-O4 6.0 % K3[pN, 20°C]: 13.6 PY-3-O2 15.0 % YSY-4-O2 2.5 % SY-3-O2 3.0 % ^ 100.0 % Mixture Example M8 B(S)-2O-O4 3.0 % Cl.p. [°C]: 75 B(S)-2O-O5 4.0 % ne[589 nm, 20°C]: 1.6225 B(S)-2O-O6 3.0 % no[589 nm, 20°C]: 1.4915 CPP-3-2 2.5 % ^n [589 nm, 20°C]: 0.1310CC-3-V33.5 % ^ ^ ^ [1 kHz, 20°C]: 3.9CC-3-V1 6.0 % ^^[1 kHz, 20°C]: 8.0CLY-3-O26.0 % ^ ^ [1 kHz, 20°C]: -4.1CPY-2-O2 6.5 % ^1[mPa s, 20°C]: 101 CPY-3-O2 9.0 % K1[pN, 20°C]: 15.0 PGIY-2-O4 6.0 % K3[pN, 20°C]: 14.2 PY-3-O2 15.0 % YSY-4-O2 2.5 % SPY-3-O4 3.0 % ^ 100.0 % Mixture Example M9 B(S)-2O-O4 3.0 % Cl.p. [°C]: 75 B(S)-2O-O5 4.0 % ne[589 nm, 20°C]: 1.6233 B(S)-2O-O6 3.0 % no[589 nm, 20°C]: 1.4919 CPP-3-2 2.5 % ^n [589 nm, 20°C]: 0.1314CC-3-V33.5 % ^ ^ ^ [1 kHz, 20°C]: 3.9CC-3-V1 6.0 % ^^[1 kHz, 20°C]: 8.0CLY-3-O26.0 % ^ ^ [1 kHz, 20°C]: -4.1CPY-2-O2 6.5 % ^1[mPa s, 20°C]: 100 CPY-3-O2 9.0 % K1[pN, 20°C]: 15.2 PGIY-2-O4 6.0 % K3[pN, 20°C]: 14.2 PY-3-O2 15.0 % YSY-4-O2 2.5 % SPY-4-O2 3.0 % ^ 100.0 % Mixture Example M10 B(S)-2O-O4 3.0 % Cl.p. [°C]: 74B(S)-2O-O54.0 % ^n [589 nm, 20°C]: 0.1314B(S)-2O-O6 3.0 % ^ ^ [1 kHz, 20°C]: -4.3CPP-3-22.5 % ^1 [mPa s, 20°C]: 101CC-3-V 33.5 % CC-3-V1 6.0 % CLY-3-O2 6.0 % CPY-2-O2 6.5 % CPY-3-O2 9.0 % PGIY-2-O4 6.0 % PY-3-O2 15.0 % YSY-4-O2 2.5 % SYY-4-O2 3.0 %^100.0 %Mixture Example M11 B(S)-2O-O4 3.0 % Cl.p. [°C]: 74.5B(S)-2O-O54.0 % ^n [589 nm, 20°C]: 0.1310B(S)-2O-O6 3.0 %^ ^ [1 kHz, 20°C]:-4.1CPP-3-22.5 % ^1 [mPa s, 20°C]: 101CC-3-V 33.5 % CC-3-V1 6.0 % CLY-3-O2 6.0 % CPY-2-O2 6.5 % CPY-3-O2 9.0 % PGIY-2-O4 6.0 % PY-3-O2 15.0 % YSY-4-O2 2.5 % SGY-4-O2 3.0 %^100.0 %Mixture Example M12 B(S)-2O-O4 3.0 % Cl.p. [°C]: 74.5B(S)-2O-O54.0 % ^n [589 nm, 20°C]: 0.1312B(S)-2O-O6 3.0 %^ ^ [1 kHz, 20°C]:-4.1CPP-3-2 2.5 % ^1[mPa s, 20°C]: 100 CC-3-V 33.5 % CC-3-V1 6.0 % CLY-3-O2 6.0 % CPY-2-O2 6.5 % CPY-3-O2 9.0 % PGIY-2-O4 6.0 % PY-3-O2 15.0 % YSY-4-O2 2.5 % SGIY-4-O2 3.0 %^ 100.0 %Mixture Example M14 The mixture example M14 consists of 99.98% of the Mixture example M1 and 0.02% of a compound of the formula ST-12b-1

[0080] ST-12b-1 Mixture Example M15 The mixture example M15 consists of 99.985% of the Mixture example M1 and 0.015% of a compound of the formula S1-1a S-1-1a Mixture Example M16 The mixture example M16 consists of 99.98% of the Mixture example M2 and 0.02% of a compound of the formula S2-1a

[0081] Mixture Example M17 B(S)-2O-O5 3.0 % Cl.p. [°C]: 98.5 CC-3-V 21.0 % ne[589 nm, 20°C]: 1.5737 CC-3-V1 4.0 % no[589 nm, 20°C]: 1.4803CC-3-4 10.0 %^n [589 nm, 20°C]:0.0934CC-3-58.0 % ^ ^ ^ [1 kHz, 20°C]: 3.4CCY-3-O1 8.0 %^ ^ [1 kHz, 20°C]:7.3CCY-3-O211.0 % ^ ^ [1 kHz, 20°C]: -3.9CLY-3-O2 9.0 %^1 [mPa s, 20°C]:136CLY-4-O2 2.5 % K1[pN, 20°C]: 19.3 CLY-5-O2 5.0 % K3[pN, 20°C]: 18.1 COB(S)-2-O4 5.0 % CY-3-O2 10.5 % YSY-4-O2 3.0 %^100.0 %Mixture Example M18 CC-3-V 19.5 % Cl.p. [°C]: 98 CC-3-V1 12.0 % ne[589 nm, 20°C]: 1.5735 CC-3-4 2.0 % no[589 nm, 20°C]: 1.4798CC-3-58.0 % ^n [589 nm, 20°C]: 0.0937CCY-3-O1 6.0 % ^^ ^[1 kHz, 20°C]: 3.4CCY-3-O211.0 % ^ ^ [1 kHz, 20°C]: 7.2CLY-3-O2 9.0 %^ ^ [1 kHz, 20°C]:-3.9CLY-3-O36.0 % ^1 [mPa s, 20°C]: 138CLY-4-O2 5.0 % K1[pN, 20°C]: 18.6 COB(S)-2-O4 5.0 % K3[pN, 20°C]: 19.0 CY-3-O2 13.5 % YSY-4-O2 3.0 % ^ 100.0 % Mixture Example M19 B(S)-2O-O5 3.0 % Cl.p. [°C]: 98.5 CC-3-V 20.25 % ne[589 nm, 20°C]: 1.5739 CC-3-V1 8.0 % no[589 nm, 20°C]: 1.4801 CC-3-4 10.0 % ^n [589 nm, 20°C]: 0.0938CC-3-5 3.5 %^ ^ ^ [1 kHz, 20°C]:3.4CCY-3-O1 8.0 % ^^[1 kHz, 20°C]: 7.3CCY-3-O211.0 % ^ ^ [1 kHz, 20°C]: -3.9CLY-3-O2 9.0 % ^1[mPa s, 20°C]: 137 CLY-4-O2 5.0 % K1[pN, 20°C]: 18.7 CLY-5-O2 5.0 % K3[pN, 20°C]: 18.6 COB(S)-2-O4 2.75 % CY-3-O2 11.5 % YSY-4-O2 3.0 % ^ 100.0 % Mixture Example M20 B(S)-2O-O4 4.0 % Cl.p. [°C]: 75 B(S)-2O-O5 4.0 % ne[589 nm, 20°C]: 1.5857 B(S)-2O-O6 3.5 % no[589 nm, 20°C]: 1.4840CC-3-V44.5 % ^n [589 nm, 20°C]: 0.1017CC-3-V1 4.0 %^ ^ ^ [1 kHz, 20°C]:3.6CLY-3-O3 4.5 % ^^[1 kHz, 20°C]: 7.1CLY-5-O25.0 % ^ ^ [1 kHz, 20°C]: -3.5CPY-2-O2 9.0 % ^1[mPa s, 20°C]: 81 CPY-3-O2 8.5 % K1[pN, 20°C]: 14.1 CY-3-O4 10.0 % K3[pN, 20°C]: 13.9 YSY-4-O2 3.0 %^ 100.0 %Mixture Example M21 B(S)-2O-O4 4.0 % Cl.p. [°C]: 75 B(S)-2O-O5 4.0 % ne[589 nm, 20°C]: 1.5850 B(S)-2O-O6 3.5 % no[589 nm, 20°C]: 1.4837CC-3-V44.5 % ^n [589 nm, 20°C]: 0.1013CCG-V-F 4.0 % ^^ ^[1 kHz, 20°C]: 3.9CLY-3-O27.5 % ^ ^ [1 kHz, 20°C]: 7.4CLY-3-O3 3.0 %^ ^ [1 kHz, 20°C]:-3.5CLY-4-O22.0 % ^1 [mPa s, 20°C]: 81CPY-2-O2 3.5 % K1[pN, 20°C]: 13.8 CPY-3-O2 9.0 % K3[pN, 20°C]: 13.9 CY-3-O2 8.0 % CY-3-O4 2.0 % CY-5-O2 2.0 % YSY-4-O2 3.0 %^ 100.0 %Mixture Example M22 B(S)-2O-O4 4.0 % Cl.p. [°C]: 74 B(S)-2O-O5 5.0 % ne[589 nm, 20°C]: 1.6128 B(S)-2O-O6 3.0 % no[589 nm, 20°C]: 1.4907CPP-3-2 9.0 %^n [589 nm, 20°C]:0.1221CC-3-V41.3 % ^ ^ ^ [1 kHz, 20°C]: 3.6CC-3-V1 8.0 %^ ^ [1 kHz, 20°C]:6.2CLY-3-O2 6.3 % ^ ^ [1 kHz, 20°C]: -2.7PGIY-2-O4 6.0 %^1 [mPa s, 20°C]:70PY-3-O2 7.6 % K1[pN, 20°C]: 15.7 PYP-2-3 1.8 % K3[pN, 20°C]: 12.7 YSY-4-O2 8.0 %^100.0 %Mixture Example M23 B(S)-2O-O4 4.0 % Cl.p. [°C]: 74 B(S)-2O-O5 5.0 % ne[589 nm, 20°C]: 1.6121 B(S)-2O-O6 3.0 % no[589 nm, 20°C]: 1.4902 CPP-3-2 8.5 % ^n [589 nm, 20°C]: 0.1219CC-3-V38.25 % ^ ^ ^ [1 kHz, 20°C]: 3.6CC-3-V1 10.0 % ^^[1 kHz, 20°C]: 6.5CLY-3-O27.75 % ^ ^ [1 kHz, 20°C]: -2.9PGIY-2-O4 6.0 %^1 [mPa s, 20°C]:73PY-3-O2 9.5 % K1[pN, 20°C]: 15.6 YSY-4-O2 8.0 % K3[pN, 20°C]: 13.1^100.0 % Mixture Example M24 B(S)-2O-O4 4.0 % Cl.p. [°C]: 74 B(S)-2O-O5 5.0 % ne[589 nm, 20°C]: 1.6124 B(S)-2O-O6 3.0 % no[589 nm, 20°C]: 1.4902CPP-3-27.5 % ^n [589 nm, 20°C]: 0.1222CC-3-V 41.25 %^ ^ ^ [1 kHz, 20°C]:3.6CC-3-V1 8.0 % ^^[1 kHz, 20°C]: 6.5CLY-3-O27.5 % ^ ^ [1 kHz, 20°C]: -2.9PGIY-2-O4 6.0 % ^1[mPa s, 20°C]: 72 PY-3-O2 7.75 % K1[pN, 20°C]: 15.4 YSY-4-O2 10.0 % K3[pN, 20°C]: 12.9 ^ 100.0 % Mixture Example M25 B(S)-2O-O4 4.0 % Cl.p. [°C]: 74.5 B(S)-2O-O5 5.0 % ne[589 nm, 20°C]: 1.6120 B(S)-2O-O6 3.0 % no[589 nm, 20°C]: 1.4904 CPP-3-2 8.0 % ^n [589 nm, 20°C]: 0.1216CC-3-V 41.75 %^ ^ ^ [1 kHz, 20°C]:3.6CC-3-V1 8.0 % ^^[1 kHz, 20°C]: 6.4CLY-3-O27.0 % ^ ^ [1 kHz, 20°C]: -2.8PGIY-2-O4 6.0 % ^1[mPa s, 20°C]: 72 PY-3-O2 7.25 % K1[pN, 20°C]: 15.6 YSY-4-O2 10.0 % K3[pN, 20°C]: 12.9^100.0 %Mixture Example M26 B(S)-2O-O4 3.5 % Cl.p. [°C]: 81.5 B(S)-2O-O5 2.0 % ne[589 nm, 20°C]: 1.5840 B(S)-2O-O6 3.0 % no[589 nm, 20°C]: 1.4823CC-3-V33.0 % ^n [589 nm, 20°C]: 0.1017CC-3-V1 6.5 %^ ^ ^ [1 kHz, 20°C]:3.8CCG-V-F 3.0 % ^^[1 kHz, 20°C]: 7.9CCY-3-O28.0 % ^ ^ [1 kHz, 20°C]: -4.0CLY-3-O2 9.0 % ^1[mPa s, 20°C]: 101 CLY-3-O3 6.0 % K1[pN, 20°C]: 15.2 CPY-3-O2 6.5 % K3[pN, 20°C]: 16.0 CY-3-O2 14.0 % CY-5-O2 1.5 % YSY-4-O2 4.0 % ^ 100.0 % Mixture Example M27 B(S)-2O-O4 4.0 % Cl.p. [°C]: 81.5 B(S)-2O-O5 4.0 % ne[589 nm, 20°C]: 1.5837 B(S)-2O-O6 3.0 % no[589 nm, 20°C]: 1.4827 CC-3-V 34.0 % ^n [589 nm, 20°C]: 0.1010CC-3-V1 6.25 %^ ^ ^ [1 kHz, 20°C]:3.9CCG-V-F 3.5 % ^^[1 kHz, 20°C]: 7.9CCY-3-O28.0 % ^ ^ [1 kHz, 20°C]: -4.0CCY-3-O3 5.75 % ^1[mPa s, 20°C]: 102 CLY-3-O2 7.0 % K1[pN, 20°C]: 15.2 CPY-3-O2 7.75 % K3[pN, 20°C]: 16.0 CY-3-O2 11.25 % CY-5-O2 2.5 % YSY-4-O2 3.0 % 100.0 % Mixture Example M28 B(S)-2O-O4 4.0 % Cl.p. [°C]: 75 B(S)-2O-O5 3.25 % ne[589 nm, 20°C]: 1.5859 B(S)-2O-O6 3.5 % no[589 nm, 20°C]: 1.4840CC-3-V44.0 % ^n [589 nm, 20°C]: 0.1019CCG-V-F 4.0 %^ ^ ^ [1 kHz, 20°C]:3.9CLY-3-O2 7.5 % ^^[1 kHz, 20°C]: 7.5CLY-3-O34.25 % ^ ^ [1 kHz, 20°C]: -3.5CLY-4-O2 2.75 % ^1[mPa s, 20°C]: 83 CPY-3-O2 9.5 % K1[pN, 20°C]: 13.8 CY-3-O2 12.5 % K3[pN, 20°C]: 14.1 PGIY-2-O4 1.25 % YSY-4-O2 3.5 %^100.0 %Mixture Example M29 B(S)-2O-O4 4.0 % Cl.p. [°C]: 81.5 B(S)-2O-O5 4.0 % ne[589 nm, 20°C]: 1.5838 B(S)-2O-O6 3.0 % no[589 nm, 20°C]: 1.4825CC-3-V 33.0 %^n [589 nm, 20°C]:0.1013CC-3-V17.25 % ^ ^ ^ [1 kHz, 20°C]: 3.9CCG-V-F 3.5 %^ ^ [1 kHz, 20°C]:7.9CCY-3-O14.0 % ^ ^ [1 kHz, 20°C]: -4.0CCY-3-O2 8.0 %^1 [mPa s, 20°C]:103CCY-3-O3 3.0 % K1[pN, 20°C]: 15.1 CLY-3-O2 6.75 % K3[pN, 20°C]: 15.8 CPY-3-O2 5.75 % CY-3-O2 9.0 % CY-5-O2 4.75 % YSY-4-O2 4.0 % ^ 100.0 % Mixture Example M30 B(S)-2O-O4 4.0 % Cl.p. [°C]: 74.5 B(S)-2O-O5 5.0 % ne[589 nm, 20°C]: 1.6130 B(S)-2O-O6 3.0 % no[589 nm, 20°C]: 1.4911 CC-3-V 50.25 % ^n [589 nm, 20°C]: 0.1219CLY-3-O29.0 % ^ ^ ^ [1 kHz, 20°C]: 3.6CLY-3-O3 1.25 % ^^[1 kHz, 20°C]: 6.4CLY-4-O25.0 % ^ ^ [1 kHz, 20°C]: -2.9PGS-2-1 8.0 % ^1[mPa s, 20°C]: 68 PY-3-O2 6.5 % K1[pN, 20°C]: 16.6 YSY-4-O2 8.0 % K3[pN, 20°C]: 12.8^100.0 %Mixture Example M31 B(S)-2O-O4 4.0 % Cl.p. [°C]: 74.5 B(S)-2O-O5 5.0 % ne[589 nm, 20°C]: 1.6137 B(S)-2O-O6 3.0 % no[589 nm, 20°C]: 1.4913 CC-3-V 49.0 % ^n [589 nm, 20°C]: 0.1224CLY-3-O29.0 % ^ ^ ^ [1 kHz, 20°C]: 3.5CLY-3-O3 1.0 % ^^[1 kHz, 20°C]: 6.3CLY-4-O25.0 % ^ ^ [1 kHz, 20°C]: -2.8CP-3-O2 2.0 %^1 [mPa s, 20°C]:69PGIY-2-O4 0.5 % K1[pN, 20°C]: 16.5 PGS-2-1 8.0 % K3[pN, 20°C]: 12.6 PY-3-O2 5.5 % YSY-4-O2 8.0 %^ 100.0 %Mixture Example M32 B(S)-2O-O4 4.0 % Cl.p. [°C]: 75 B(S)-2O-O5 5.0 % ne[589 nm, 20°C]: 1.6122 B(S)-2O-O6 3.0 % no[589 nm, 20°C]: 1.4903CC-3-V 50.25 %^n [589 nm, 20°C]:0.1219CLY-3-O29.0 % ^ ^ ^ [1 kHz, 20°C]: 3.6CLY-4-O2 2.0 %^ ^ [1 kHz, 20°C]:6.5CPY-3-O2 2.25 % ^ ^ [1 kHz, 20°C]: -2.9CP-3-O2 2.0 %^1 [mPa s, 20°C]:70PGIY-2-O4 6.0 % K1[pN, 20°C]: 15.7 PGS-2-1 5.0 % K3[pN, 20°C]: 12.8 PY-3-O2 3.5 % YSY-4-O2 8.0 %^ 100.0 %Mixture Example M33 B(S)-2O-O4 3.0 % T(N,I)[°C]: 76.0 B(S)-(c5)1O-O2 4.0 % ^n [589 nm, 20°C]: 0.1303 B(S)-2O-O6 3.0 % ne[589 nm, 20°C]: 1.6211 CC-3-V 36.0 % no[589 nm, 20°C]: 1.4908CC-3-V16.0 % ^ ^ [1 kHz, 20°C]: -4.1CLY-3-O2 9.0 %^ ^ ^ [1 kHz, 20°C]:3.9CPY-2-O2 1.5 % ^^[1 kHz, 20°C]: 8.0CPY-3-O29.0 % ^1 [mPa s, 20°C]: 95PGIY-2-O4 6.0 % PY-3-O2 12.5 % YSY-4-O2 10.0 %^100.0 % Mixture Example M34 B(S)-2O-O4 3.0 % T(N,I)[°C]: 75.0B(S)-(c5-3en)1O-O44.0 % ^n [589 nm, 20°C]: 0.1300B(S)-2O-O6 3.0 % ne[589 nm, 20°C]: 1.6207 CC-3-V 36.0 % no[589 nm, 20°C]: 1.4907CC-3-V16.0 % ^ ^ [1 kHz, 20°C]: -4.0CLY-3-O2 9.0 %^ ^ ^ [1 kHz, 20°C]:3.9CPY-2-O21.5 % ^ ^ [1 kHz, 20°C]: 7.9CPY-3-O2 9.0 %^1 [mPa s, 20°C]:95PGIY-2-O4 6.0 % PY-3-O2 12.5 % YSY-4-O2 10.0 % ^ 100.0 % Mixture Example M35 B(S)-2O-O4 3.0 % T(N,I)[°C]: 74.0B(S)-2O-O5 4.0 %^n [589 nm, 20°C]:0.1280B(S)-2O-O6 3.0 % ne[589 nm, 20°C]: 1.6179 CC-3-V 36.0 % no[589 nm, 20°C]: 1.4899 CC-3-V1 6.0 % ^ ^ [1 kHz, 20°C]: -4.3CLY-3-O29.0 % ^ ^ ^ [1 kHz, 20°C]: 3.9CPY-2-O2 1.5 %^ ^ [1 kHz, 20°C]:8.2CPY-3-O29.0 % ^1 [mPa s, 20°C]: 97PGIY-2-O4 6.0 % PY-3-O2 12.5 % LPOY-3-O2 3.0 % YSY-4-O2 7.0 % 100.0 % Mixture Example M36 B(S)-2O-O4 4.0 % T(N,I)[°C]: 73B(S)-2O-O55.0 % ^n [589 nm, 20°C]: 0.1360B(S)-2O-O6 3.0 % ne[589 nm, 20°C]: 1.6316 CC-3-V 28.5 % no[589 nm, 20°C]: 1.4946CC-3-V17.5 % ^ ^ [1 kHz, 20°C]: -3.2CCP-V-1 7.5 %^ ^ ^ [1 kHz, 20°C]:3.7CAIY-3-O23.0 % ^ ^ [1 kHz, 20°C]: 6.8CPY-3-O2 10.0 %^1 [mPa s, 20°C]:87PP-1-2V1 7.0 % PY-1-O2 7.0 % PY-3-O2 3.0 % PYP-2-3 8.0 % CLY-3-O2 1.5 % YSY-4-O2 5.5 % ^ 100.0 % Mixture Example M37 Mixture Example M37 consists of 99.975 % of Mixture Example 1 and 0.025 % of the compound ST-3d Mixture Example M38 Mixture Example M38 consists of 99.97 % of Mixture Example 2 and 0.03 % of the compound ST-3e Mixture Example M39 Mixture Example M39 consists of 99.97 % of Mixture Example 1 and 0.03 % of the compound ST-3c-1 Mixture Example M40 B(S)-2O-O4 3.0 % T(N,I)[°C]: 78.0 B(S)-2O-O5 4.0 % B(S)-2O-O6 3.0 % CC-3-V 36.0 % CC-3-V1 6.0 % CLY-3-O2 9.0 % CPY-2-O2 1.5 % CPY-1V-O2 9.0 % PGIY-2-O4 6.0 % PY-V2-O2 12.5 % YSY-4-O2 10.0 % 100.0 %Mixture Example M41 B(S)-1V1O-O1(c5) 3.0 % CC-3-V 21.0 % CC-3-V1 4.0 % CC-3-4 10.0 % CC-3-5 8.0 % CEY-3-O2 2.0 % CCEY-3-O2 4.0 % CCY-3-O1 4.0 % CAIY-3-O2 9.0 % CLY-3-O2 9.0 % CLY-4-O2 2.5 % CLY-5-O2 5.0 % COB(S)-2-O4 5.0 % CY-3-O2 8.5 % LPOY-3-O2 2.0 % YSY-4-O2 3.0 % 100.0 % Mixture Example M42 B(S)-2O-O4 3.0 % Cl.p. [°C]: 77.0 B(S)-2O-O5 4.0 % B(S)-2O-O6 3.0 % CPP-1V-2 2.5 % CC-3-V 33.5 % CC-3-V1 6.0 % CLY-V-O2 6.0 % CPY-2-O2 6.5 % CPY-3-O2 9.0 % PPY-3-O2 6.0 % PY-2-O2 15.0 % YSY-4-O2 5.5 %^100.0 % Mixture Example M43 B(S)-2O-O4 4.0 % Cl.p. [°C]: 74.9B(S)-2O-O55.0 % ^n [589 nm, 20°C]: 0.1365B(S)-2O-O6 3.0 % ne[589 nm, 20°C]: 1.6324 CC-3-V 28.5 % no[589 nm, 20°C]: 1.4959CC-3-V17.5 % ^ ^ [1 kHz, 20°C]: -3.2CCP-V2-1 7.5 %^ ^ ^ [1 kHz, 20°C]:3.7CCY-3-O23.0 % ^ ^ [1 kHz, 20°C]: 6.8CPY-3-O2 10.0 %^1 [mPa s, 20°C]:86PP-1-2V 7.0 % K1[pN, 20°C]: 15.3 PY-1-O2 7.0 % K3[pN, 20°C]: 15.1 PY-3-O2 3.0 % PYP-2-3 8.0 % CLY-3-O2 1.5 % YSY-4-O2 5.5 % ^ 100.0 % Mixtures The polymerisable mixtures P1 to P9 are prepared from the nematic mixtures given in Table 1 by adding a reactive mesogen (RM) selected from the group of compounds of the formulae RM-1, RM-17, RM-35, RM-64 and RM-171, in the amount given in Table 1 (% RM). 7

[0082] Table 1: Polymerisable Mixtures Mixture Example P10 The polymerisable mixture P10 consists of 99.434% of Mixture Example M1, 0.300% of RM-1, 0.200% of RM-145, 0.050% of RM-163, 0.001% of Irganox® 1076 and 0.015% of the compound ST-3a-1. OX®-1076

Claims

Patent Claims 1. A liquid crystal medium comprising one or more compounds of the formula I Iin which R1and R2, identically or differently, denote H, halogen, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms, or branched alkyl, alkoxy, alkenyl or alkenyloxy each having 3 to 15 C atoms, where one or more CH2groups in these radicals may each be-C ^C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, L11, L12, L13and L14each, independently of one another, denote F, Cl, CF3or CHF2, and Y1denotes H, F, Cl, CF3, CHF2or CH3; and one or more compounds selected from the group of compounds of the formulae IIA, IIB, IIC and IIDin which R2A, R2B, R2Cand R2Didentically or differently, denote H, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl, alkenyloxy each having 3 to 15 C atoms, where one or more CH2groups in these radicals may each be-OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, L1and L2, each, independently of one another, denote F, Cl, CF3or CHF2, Y denotes H, F, Cl, CF3, CHF2or CH3, Z2, Z2Band Z2Deach, independently of one another, denote a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF- or -CH=CHCH2O-, (O) denotes O or a single bond, p denotes 0, 1 or 2, q denotes 0 or 1, and v denotes an integer from 1 to 6.

2. The liquid crystal medium according to claim 1, wherein the medium comprises one or more compounds selected from the group of compounds of the formulae IIA- 10 and IIA-16alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, and alkenyl denotes a straight-chain alkenyl radical having 2-6 C atoms, in a total concentration in the range of from 0% to 8%.

3. The liquid crystal medium according to claim 1 or 2, wherein the medium comprises one or more compounds of the formula IID-4in which alkyl independently denotes a straight-chain alkyl radical having 1-6 C atoms, and alkenyl denotes a straight-chain alkenyl radical having 2-6 C atoms.

4. The liquid crystal medium according to claim 1, wherein in formula I Y1denotes H or CH3, and L11, L12, L13and L14denote F.

5. The liquid crystal medium according claim 1, wherein in formula I R1denotes straight chain alkyl having 1 to 7 C atoms, straight chain alkenyl having 2 to 7 C atoms, where one or more CH2groups in these radicals may each beandR2denotes straight chain alkoxy having 1 to 7 C atoms, where one or more CH2groups in these radicals may each be replaced, independently of one another,6. The liquid crystal medium according to one or more of claims 1 to 5, wherein the medium comprises one or more compounds of the formula IIIin which R31and R32each, independently of one another, denote H, an alkyl or alkoxy radical having 1 to 15 C atoms, where one or more CH2groups in these radicals may-OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, A31on each occurrence, independently of one another, denotes a) 1,4-cyclohexenylene or 1,4-cyclohexylene radical, in which one or two non- adjacent CH2groups may be replaced by -O- or -S-, b) a 1,4-phenylene radical, in which one or two CH groups may be replaced by N, or c) a radical from the group spiro[3.3]heptane-2,6-diyl, 1,4-bicyclo[2.2.2]- octylene, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4- tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl and fluorene-2,7-diyl, where the radicals a), b) and c) may be mono- or polysubstituted by halogen atoms,n denotes 0, 1 or 2, Z31on each occurrence independently of one another denotes -CO-O-, -O-CO-, -CF2O- , -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -(CH2)4-, -CH=CH-CH2O-, -C2F4-, -CH2CF2-, -CF2CH2-, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C ^C- or a single bond, L31and L32each, independently of one another, denote F, Cl, CF3or CHF2, and W denotes O or S.

7. The liquid crystal medium according to claim 6, wherein W denotes S.

8. The liquid crystal medium according to one or more of claims 1 to 7, wherein the medium comprises one or more compounds of formula III-3in which R31, R32identically or differently, denote H, an alkyl or alkoxy radical having 1 to 15 C atoms, in which one or more CH2groups in these radicals are optionallys are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by halogen.

9. The liquid crystal medium according to one or more of claims 1 to 8, wherein the medium comprises one or more compounds of the formula VIin whichR61and R62denote H, F, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl, alkenyloxy each having 3 to 15 C atoms, where one or more CH2groups in these radicals may each be replaced, independently of oneor -O-CO- in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, X61to X66, identically or differently, denote H or F, Z61and Z62, identically or differently, denote CH2CH2or a single bond.

10. The liquid crystal medium according to one or more of claims 1 to 9, wherein the medium comprises one or more compounds of the formula IVin which R41denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms, R42denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkoxy radical having 1 to 6 C atoms, or an unsubstituted alkenyl radical having 2 to 7 C atoms.

11. The liquid crystal medium according to one or more of claims 1 to 10, wherein the medium comprises one or more compounds selected from the compounds of the formulae IV-3-1 and IV-3-2:in which alkyl denotes n-alkyl having 1 to 7 C-atoms.

12. The liquid crystal medium according to one or more of claims 1 to 11, wherein the medium comprises one or more compounds of the formula Vin which R51, R52denote alkyl having 1 to 7 C atoms, alkoxy having 1 to 7 C atoms, or alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7 C atoms,, Z51and Z52, identically or differently, denote -CH2-CH2-, -CH2-O-, -CH=CH-, -C≡C-, -COO- or a single bond, and n is 1 or 2.

13. The liquid crystal medium according to one or more of claims 1 to 12, wherein the medium comprises a polymerisable compound.

14. A liquid crystal display comprising the liquid crystal medium according to any one of claims 1 to 13.

15. The liquid crystal display according to claim 14, wherein the display is a VA, IPS, FFS, PS-VA, PS-IPS or PS-FFS type display.

16. Use of the liquid crystal medium according to one or more of claims 1 to 13 in a VA, IPS, FFS, PS-VA, PS-IPS or PS-FFS display.

17. Energy saving display for gaming comprising the liquid crystal medium according to one or more of claims 1 to 13.

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