Liquid crystal media

Abstract

The present invention relates to liquid-crystal (LC) media having positive dielectric anisotropy and to liquid-crystal displays (LCDs) comprising these media, in particular to displays addressed by means of an active matrix, and in particular to LC displays of the TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, XB-FFS, PS-FFS, SA-HB-FFS, SA-XB-FFS, polymer-stabilized SA-HB-FFS, polymer-stabilized SA-XB-FFS, positive VA or positive PS-VA type.

Description

Technical Field

[0001] The present invention relates to liquid-crystal (LC) media having positive dielectric anisotropy and to liquid-crystal displays (LCDs) comprising these media, in particular to displays addressed by means of an active matrix, and in particular to LC displays of the TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, PS-HB-FFS, SA-HB-FFS, polymer-stabilized SA-HB-FFS, positive VA or positive PS-VA type. Background Art

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

[0003] In addition to these modes, there are also electro-optical modes that utilize an electric field substantially parallel to the substrate or liquid crystal layer. For example, WO91 / 10936 discloses a liquid crystal display in which an electric signal is generated in such a way that the electric field has an effective component parallel to the liquid crystal layer, and it is known as an in-plane switching (IPS) display. The principle of operating such a display is described, for example, by RA Soref in the Journal of Applied Physics, Vol. 45, No. 12, pp. 5466-5468 (1974).

[0004] IPS displays consist of a liquid crystal layer between two substrates in a planar orientation. Two electrodes are arranged on only one of the two substrates, preferably in an interdigitated comb structure. When a voltage is applied to the electrodes, an electric field with an effective component parallel to the liquid crystal layer is generated between them. This causes the liquid crystal molecules to realign in the plane of the layer.

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

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

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

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

[0009] Further improvements have been achieved through the so-called HB-FFS mode. One of the unique features of the HB-FFS mode is its ability to achieve higher transmittance compared to conventional FFS technology, which allows the panel to be operated with less energy consumption.

[0010] Liquid crystal compositions suitable for LCDs, in particular FFS and IPS displays, are known in the prior art and are, for example, known from JP 07-181 439 (A), EP 0 667 555, EP 0 673 986, DE 195 09 410, DE 195 28 106, DE 19528 107, WO 96 / 23 851 and WO 96 / 28 521. However, these compositions have certain disadvantages. Among other drawbacks, most of them result in disadvantageously long addressing times, have insufficient resistivity values ​​and / or require excessively high operating voltages. In this context, there is a need not only to improve the operating properties but also to improve the shelf life.

[0011] FFS and IPS displays can be operated as active matrix displays (AMD) or passive matrix displays (PMD). In the case of active matrix displays, the individual pixels are typically addressed by integrated, non-linear active elements, such as thin film transistors (TFTs), while in the case of passive matrix displays, the individual pixels are typically addressed by multiplexing methods known in the art.

[0012] Preferably, the display according to the invention is addressed by an active matrix, preferably by a TFT matrix.However, the liquid crystals according to the invention can also be advantageously used in displays having other known addressing modes.

[0013] Typical applications of in-plane switching (IPS) and fringe field switching (FFS) technologies are monitors, notebook computers, TVs, mobile phones, tablet PCs, etc.

[0014] Both IPS and FFS technologies have certain advantages over other LCD technologies, such as, for example, vertical alignment (VA) technology, such as the wide viewing angle dependence of the contrast ratio.

[0015] The provision of alternative liquid crystal media and their use in displays with high transmittance, a good black state, and high contrast are central challenges for modern FFS and IPS applications. Furthermore, modern applications also require good low-temperature stability and fast addressing times.

[0016] In particular, there is a desire for media with low birefringence that have low birefringence while having sufficient stability at low temperatures. Such media are useful for mobile applications, such as in automotive applications that are exposed to harsh environmental conditions, such as those that may occur at very low temperatures.

[0017] This is achieved by providing liquid-crystalline media as described and claimed below.

[0018] It was observed that by using a liquid crystal having positive dielectric anisotropy and also having an increased dielectric constant ε perpendicular to the longitudinal axis of the liquid crystal molecules ⊥ Liquid crystal media can achieve high brightness in displays such as those in the HB-FFS mode. This can be achieved by adding a limited amount of a liquid crystal medium with negative dielectric anisotropy and high ε ⊥ properties of liquid crystal compounds while maintaining the positive dielectric anisotropy of the entire medium. ⊥ Compounds with a γ1 have some disadvantages. For example, this can lead to higher values ​​of the rotational viscosity γ1 and, therefore, to higher values ​​of the rotational viscosity γ1 and the elastic constant K for torsional deformation. 22 The ratio γ1 / K 22 This results in higher response times. 22 and the elastic constant K of the splay deformation 11 Approximately proportional (K 22 The value is usually around K 11 half of the value of ), which can be obtained by measuring γ1 and K 11 Easily determined.

[0019] Another disadvantage is that the reliability (VHR) of HB-FFS mixtures may be worse than that of conventional FFS mixtures. Summary of the Invention

[0020] It was an object of the present invention to provide liquid-crystalline media, preferably for FFS and IPS displays, in particular for HB-FFS displays, but also for TN, positive VA or STN displays, and in particular for active-matrix displays such as those addressed by TFTs, which do not exhibit the disadvantages indicated above or do so only to a lesser extent, and preferably have a high resistivity, a low threshold voltage, a high dielectric anisotropy, good low-temperature stability (LTS), a fast response time and a low rotational viscosity, and enable high brightness to be achieved.

[0021] A further object of the present invention was to provide improved liquid-crystalline media suitable for use in HB-FFS displays which have improved reliability compared to prior art media while maintaining a high transmittance.

[0022] In order to solve this problem, the present invention provides a liquid-crystalline medium according to claim 1 .

[0023] Advantageous embodiments of the invention are the subject matter of the dependent claims or can also be taken from the description.

[0024] The present invention relates to a liquid crystal medium having positive dielectric anisotropy, comprising

[0025] a) one or more compounds of formula I

[0026]

[0027] in,

[0028] R 1 represents H, alkyl or alkoxy having 1 to 12 C atoms, wherein one or more CH2 groups in these radicals are optionally independently of one another in such a way that the O atoms are not directly connected to one another -CH=CH-, -C≡C-, -O-, -CO-O- or -O-CO-, and wherein 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 cycloalkyl having 3 to 9 C atoms, wherein one or more H atoms may be replaced by F, and

[0029] Y 1 represents H or CH3, preferably H;

[0030] b) one or more compounds selected from the group consisting of compounds of formula II and formula III

[0031]

[0032]

[0033] in

[0034] R 2 and R 3 With the above for R 1 The meaning given

[0035]

[0036] Independently express

[0037]

[0038] L 21 、L 22 、L 31 and L 32 represent H or F independently of each other,

[0039] Y 2 、Y 3 Identically or differently represent H or CH3,

[0040] X 2 and X 3 independently of one another represent halogen, haloalkyl or haloalkoxy having 1 to 3 C atoms, or haloalkenyl or haloalkenyloxy having 2 or 3 C atoms, preferably F, Cl, CF3, OCF3 or OCHF2, more preferably F or OCF3,

[0041] Z 3 represents -CH2CH2-, -CF2CF2-, -COO-, trans-CH=CH-, trans-CF=CF-, -CH2O-, or a single bond, and

[0042] l, m, n and o are independently 0 or 1, wherein the compounds of formula I are excluded from the compounds of formula III; and

[0043] c) one or more compounds of formula LY

[0044]

[0045] in

[0046] R Y1 and R Y2 With the above for R 1 The meaning given, and L 1 and L 2 Indicates F or Cl.

[0047] The combination of compounds of the formula I with compounds of the formula II and / or III, and additionally with compounds of LY, leads to liquid-crystalline media exhibiting a moderately positive dielectric anisotropy and at the same time an increased dielectric constant ε perpendicular to the longitudinal axis of the liquid-crystalline molecules. ⊥ , while maintaining low rotational viscosity and low γ1 / K 22 and γ1 / K 11 This enables LCDs, especially those in HB-FFS, FFS, and IPS modes, to have high brightness and transmittance as well as fast response time.

[0048] In particular, the low temperature stability (LTS) of the medium according to the invention is very high. The medium is sufficiently stable down to temperatures of -40°C, which is why it is particularly suitable for mobile applications, such as automotive applications.

[0049] The liquid-crystalline media according to the invention are suitable for mobile applications and TFT applications, such as mobile phones and PDAs. Furthermore, the liquid-crystalline media according to the invention are particularly suitable for use in FFS, HB-FFS and IPS displays based on dielectrically positive liquid crystals.

[0050] The liquid-crystalline media according to the invention, based on dielectrically positive liquid crystals, are also suitable for large-format TV applications in liquid-crystalline displays in the FFS, HB-FFS and IPS modes and their polymer-stabilized variants.

[0051] The present invention also relates to the use of the liquid-crystalline media as described above and below for electro-optical purposes, in particular for liquid-crystal displays, shutter glasses, LC windows, 3D applications, preferably for TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, PS-HB-FFS, SA-HB-FFS, polymer-stabilized SA-HB-FFS, positive VA and positive PS-VA displays, very preferably for FFS, HB-FFS, IPS, PS-HB-FFS and PS-IPS displays.

[0052] The invention further relates to an electro-optical liquid-crystal display comprising a liquid-crystal medium as described above and below, in particular a TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, PS-HB-FFS, SA-HB-FFS, polymer-stabilized SA-HB-FFS, positive VA or positive PS-VA display, preferably a FFS, HB-FFS, IPS, PS-HB-FFS or PS-IPS display.

[0053] In the present application, all atoms also include their isotopes. In particular, one or more hydrogen atoms (H) can be replaced by deuterium (D), which is particularly preferred in some embodiments; a high degree of deuteration enables or simplifies analytical determination of compounds, particularly at low concentrations.

[0054] In this context, alkyl and / or alkoxy refers to straight-chain, branched or cyclic alkyl groups. It is preferably straight-chain, has 2, 3, 4, 5, 6 or 7 carbon atoms, and thus preferably represents ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy or heptyloxy, further preferably methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy or tetradecyloxy.

[0055] In this context, the branched alkyl group is preferably isopropyl, s-butyl, isobutyl, isopentyl, 2-methylbutyl, 2-methylhexyl or 2-ethylhexyl.

[0056] As used herein, cyclic alkyl refers to straight-chain or branched alkyl or alkenyl radicals having up to 12 C atoms, preferably alkyl radicals having 1 to 7 C atoms, wherein the CH radical is replaced by a carbocyclic ring having 3 to 5 C atoms, very preferably selected from cyclopropylalkyl, cyclobutylalkyl, cyclopentylalkyl and cyclopentenylalkyl, wherein alkyl is a straight-chain alkyl radical having 1 to 5 C atoms.

[0057] In this context, oxaalkyl preferably denotes straight-chain 2-oxapropyl (=methoxymethyl), 2-oxabutyl (=ethoxymethyl) or 3-oxabutyl (=2-methoxyethyl), 2-oxapentyl, 3-oxapentyl or 4-oxapentyl, 2-oxahexyl, 3-oxahexyl, 4-oxahexyl or 5-oxahexyl, or 2-oxaheptyl, 3-oxaheptyl, 4-oxaheptyl, 5-oxaheptyl or 6-oxaheptyl, or 2-oxaoctyl, 3-oxaoctyl, 4-oxaoctyl, 5-oxaoctyl, 6-oxaoctyl or 7-oxaoctyl, 2-oxanonyl, 3-oxanonyl, 4-oxanonyl, 5-oxanonyl, 6-oxanonyl, 7-oxanonyl or 8-oxanonyl, 2-oxadecyl, 3-oxadecyl, 4-oxadecyl, 5-oxadecyl, 6-oxadecyl, 7-oxadecyl, 8-oxadecyl or 9-oxadecyl.

[0058] In the present context, alkenyl, i.e. an alkyl radical in which one CH2 group has been replaced by -CH=CH-, may be straight-chain or branched. It is preferably straight-chain and has 2 to 10 C atoms. Thus, it particularly denotes vinyl, prop-1-enyl or prop-2-enyl, but-1-enyl, but-2-enyl or but-3-enyl, pent-1-enyl, pent-2-enyl, pent-3-enyl or pent-4-enyl, hex-1-enyl, hex-2-enyl, hex-3-enyl, hex-4-enyl or hex-5-enyl, hept-1-enyl, hept-2-enyl, hept-3-enyl, hept-4-enyl, hept-5-enyl or hept-6-enyl, oct-1-enyl, oct-2-enyl, oct-3-enyl, oct-4-enyl, oct-5-enyl or oct-6-enyl. -2-enyl, oct-3-enyl, oct-4-enyl, oct-5-enyl, oct-6-enyl or oct-7-enyl, non-1-enyl, non-2-enyl, non-3-enyl, non-4-enyl, non-5-enyl, non-6-enyl, non-7-enyl or non-8-enyl, dec-1-enyl, dec-2-enyl, dec-3-enyl, dec-4-enyl, dec-5-enyl, dec-6-enyl, dec-7-enyl, dec-8-enyl or dec-9-enyl.

[0059] In this context, alkyl or alkenyl groups which are at least monosubstituted by halogen are preferably straight-chain, the halogen being preferably F or Cl. In the case of polysubstitution, the halogen is preferably F. The resulting groups also include perfluorinated groups. In the case of monosubstitution, the fluorine or chlorine substituent can be in any desired position, but is preferably in the ω position.

[0060] In this context, mono- or polyfluorinated alkyl or alkoxy groups having 1, 2 or 3 C atoms, or mono- or polyfluorinated alkenyl groups having 2 or 3 C atoms, are particularly preferably F, Cl, CF3, CHF2, OCF3, OCHF2, OCFHCF3, OCFHCHF2, OCFHCHF2, OCF2CH3, OCF2CHF2, OCF2CHF2, OCF2CF2CHF2, OCF2CF2CHF2, OCFHCF2CF3, OCFHCF2CHF2, OCF2CF2CF3, OCF2CF2CClF2, OCC1FCF2CF2CF3, OCH═CF2 or CH═CF2, very particularly preferably F or OCF3, and also CF3, OCF═CF2, OCHF2 or OCH═CF2.

[0061] The compound of formula I is preferably selected from the compounds of formulae I-1 to I-10:

[0062]

[0063]

[0064]

[0065] Preferably, the medium comprises one or more compounds of formula II, preferably selected from the compounds of formulae II-1 to II-3, very preferably selected from the compounds of formulae II-1 and II-3

[0066]

[0067] The radicals occurring therein have the corresponding meanings given above in formula II, and in formula II-1, the radical L 23 and L 24 Independently of each other and independently of other parameters, represents H or F, and in formula II-2, preferably,

[0068] Independently express

[0069]

[0070] In formulae II-1, II-2 and II-3, L 21 and L 22 or L 23 and L 24 Preferably, both are F.

[0071] In another preferred embodiment of formula II-1 and II-2, L 21 、L 22 、L 23 and L 24 Both represent F.

[0072] The compound of formula II-1 is preferably selected from the compounds of formulae II-1a to II-1h,

[0073]

[0074]

[0075] The radicals occurring therein have the corresponding meanings given above.

[0076] In a preferred embodiment of the present invention, the medium comprises one or more compounds selected from the group consisting of compounds of formulae II-1a to II-1h, wherein L 21 and L 22 , and / or L 23 and L 24 Both are F.

[0077] In another preferred embodiment, the medium comprises a compound selected from the group consisting of compounds of formula II-1a to II-1h, wherein L 21 、L 22 、L 23 and L 24 All are F.

[0078] Particularly preferred compounds of formula II-1 are

[0079]

[0080] where R 2 has the meaning given above.

[0081] Preferably, the compound of formula II-2 is selected from the compounds of formula II-2a to II-2c,

[0082]

[0083] The radicals occurring therein have the corresponding meanings given above, and preferably, L 21 and L 22 All are F.

[0084] Preferably, the compound of formula II-3 is selected from compounds of formula II-3a to II-3e,

[0085]

[0086]

[0087] The radicals occurring therein have the corresponding meanings given above and preferably,

[0088] L 21 and L 22 Both are F, and L 23 and L 24 Both are H or L 21 、L 22 、L 23 and L 24 All are F.

[0089] Particularly preferred compounds of formula II-3 are

[0090]

[0091]

[0092] where R 2 has the meaning given above.

[0093] In addition to the preferred compounds of formula II described above, the medium optionally comprises one or more compounds of formula II selected from the group consisting of compounds of formulae IIA1 to IIA7:

[0094]

[0095]

[0096] where R 2 and X2 Having the meaning given in formula II or one of the preferred meanings given above and below.

[0097] Preferred compounds are compounds of the formulae IIA1, IIA2 and IIA3, very preferably compounds of the formulae IIA1 and IIA2.

[0098] In the compounds of Formulae IIA1 to IIA7, R 2 preferably represents an alkyl radical having 1 to 6 C atoms, very preferably an ethyl radical or an n-propyl radical, and X 2 Preferably it represents F or OCF3, very preferably F.

[0099] In another preferred embodiment of the present invention, the medium comprises one or more compounds of the formula III, preferably selected from the group consisting of formulae III-1 and III-2, preferably formula III-2:

[0100]

[0101] The radicals and parameters occurring therein have the corresponding meanings given above for formula III.

[0102] Preferably, the compound of formula III-1 is selected from the compounds of formula III-1a and III-1b,

[0103]

[0104] The radicals occurring therein have the corresponding meanings given above, and L 33 and L 34 represents H or F independently of each other.

[0105] The compound of formula III-1a is preferably selected from the compounds of formulae III-1a-1 to III-1a-6

[0106]

[0107]

[0108] where R 3 has the meaning given above.

[0109] Preferably, the compound of formula III-2 is selected from the compounds of formula III-2a to III-2m

[0110]

[0111]

[0112]

[0113] The radicals occurring therein have the corresponding meanings given above, and L 35 and L 36 represents H or F independently of each other.

[0114] Preferably, the compound of formula II-2a is selected from the compounds of formula III-2a-1 to III-2a-4

[0115]

[0116] where R 3 has the meaning given above.

[0117] The compound of formula III-2b is preferably selected from the group consisting of formula III-2b-1 and III-2b-2, preferably the compound of formula III-2b-2

[0118]

[0119] where R 3 has the meaning given above.

[0120] The compound of formula II-2c is preferably selected from the compounds of formula III-2c-1 to III-2c-5

[0121]

[0122] where R 3 has the meaning given above.

[0123] The compounds of formula III-2d and III-2e are preferably selected from the compounds of formula III-2d-1 and III-2e-1

[0124]

[0125] where R 3 has the meaning given above.

[0126] The compound of formula III-2f is preferably selected from the compounds of formula III-2f-1 to III-2f-7

[0127]

[0128] where R 3 has the meaning given above.

[0129] The compound of formula III-2g is preferably selected from the compounds of formula III-2g-1 to III-2g-7

[0130]

[0131]

[0132] where R 3 has the meaning given above.

[0133] The compound of formula III-2h is preferably selected from the compounds of formula III-2h-1 to III-2h-5

[0134]

[0135]

[0136] where R 3 has the meaning given above.

[0137] The compound of formula III-2i is preferably selected from the compounds of formula III-2i-1 to III-2i-3

[0138]

[0139] where R 3 has the meaning given above.

[0140] The compound of formula III-2j is preferably selected from the compounds of formula III-2j-1 to III-2j-3

[0141]

[0142] where R 3 has the meaning given above.

[0143] The compound of formula III-2k is preferably selected from the compounds of formulae III-2k-1 to III-2k-6

[0144]

[0145]

[0146] where R 3 has the meaning given above.

[0147] The compound of formula III-21 is preferably selected from the compounds of formula III-21-1 to III-21-6

[0148]

[0149]

[0150] where R 3 has the meaning given above.

[0151] The compound of formula III-2m is preferably selected from the compounds of formula III-2m-1

[0152]

[0153] As an alternative or in addition to the compounds of formula III-1 and / or III-2, the medium according to the invention optionally comprises one or more compounds of formula III-3,

[0154]

[0155] wherein the radicals and parameters have the corresponding meanings given above in formula III,

[0156] Preferably, it is formula III-3a,

[0157]

[0158] where R 3 has the meaning given above.

[0159] In addition to the preferred compounds of formula III described above, the medium optionally comprises one or more compounds selected from the group consisting of formulae IIIA-1 to IIIA-21:

[0160]

[0161]

[0162]

[0163]

[0164] where R 3 and X 3 has the meanings given for formula III or one of the preferred meanings given above and below.Preferred compounds are compounds of the formulae IIIA1, IIIA4, IIIA6, IIIA16, IIIA19 and IIIA20.

[0165] In the compounds of Formulae IIIA1 to IIIA21, R 3 preferably represents an alkyl radical having 1 to 6 C atoms, very preferably an ethyl or propyl radical, X 3 Preferably it represents F or OCF3, very preferably F.

[0166] The compound of formula LY is preferably selected from the formulae LY-1, LY-2 and LY-3, very preferably selected from the formula LY-1:

[0167]

[0168] where R Y1has one of the meanings given above in formula LY, and preferably represents optionally fluorinated alkyl or cycloalkyl having 1 to 7 C atoms, preferably alkyl having 1 to 7 C atoms, (O) represents O or a single bond, v is 1, 2, 3, 4, 5, 6 or 7.

[0169] Particularly preferred compounds of formula LY-1 are selected from the following:

[0170]

[0171] Alternatively or additionally, the medium comprises compounds LYA-1, LYA-2 and / or LYA-3

[0172]

[0173]

[0174] Where n is an integer between 1 and 7.

[0175] Preferably, the medium according to the invention comprises one or more compounds of formula IV

[0176]

[0177] in

[0178] R 11 represents a straight-chain alkyl group having 1 to 12 C atoms or a branched or cyclic alkyl group having 3 to 12 C atoms, or a straight-chain alkenyl group having 2 to 12 C atoms or a branched alkenyl group having 3 to 12 C atoms or a cyclic alkenyl group having 5 to 12 C atoms, wherein one or more H atoms are optionally replaced by fluorine, preferably a straight-chain alkenyl group having 2 to 12 C atoms,

[0179] R 12 represents a straight-chain alkyl or alkoxy group having 1 to 12 C atoms or a branched or cyclic alkyl or alkoxy group having 3 to 12 C atoms, or a straight-chain alkenyl group having 2 to 12 C atoms or a branched alkenyl group having 3 to 12 C atoms or a cyclic alkenyl group having 5 to 12 C atoms, wherein one or more H atoms are optionally replaced by fluorine, preferably a straight-chain alkyl group having 1 to 12 C atoms, very preferably a group having 1 to 7 C atoms.

[0180] The compound of formula IV is preferably selected from the compounds of formulae IV-1 to IV-4, very preferably the compound of formula IV-3

[0181]

[0182]

[0183] in

[0184] Alkyl and alkyl' independently of one another denote an alkyl group having 1 to 7 C atoms, preferably having 2 to 5 C atoms,

[0185] alkoxy represents an alkoxy group having 1 to 5 C atoms, preferably having 2 to 4 C atoms,

[0186] alkenyl represents an alkenyl radical having 2 to 5 C atoms, preferably having 2 to 4 C atoms, particularly preferably 2 C atoms, and

[0187] Alkenyl′ denotes alkenyl having 2 to 5 C atoms, preferably having 2 to 4 C atoms, particularly preferably having 2 to 3 C atoms.

[0188] In a preferred embodiment, the medium according to the invention comprises one or more compounds of the formula IV selected from the formulae IV-1 to IV-4 in combination with one or more compounds selected from the formulae IVA-1 to IVA-18:

[0189]

[0190]

[0191]

[0192] wherein alkyl represents methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or n-pentyl.

[0193] Preferably, the medium comprises one or more compounds of formula IV-1, preferably selected from the group consisting of compounds of formulae IV-1-1 to IV-1-6

[0194]

[0195]

[0196] Preferably, the medium according to the invention comprises one or more compounds of the formula IV-2-1 and / or IV-2-2

[0197]

[0198] Preferably, the medium according to the invention comprises a compound of the formula IV-3, very preferably a compound selected from the group consisting of the formulae IV-3-1 to IV-3-6, in particular a compound of the formula IV-3-2 and / or IV-3-6:

[0199]

[0200]

[0201] Preferably, the medium according to the invention comprises a compound of formula IV-4, in particular a compound selected from the group consisting of formulae IV-4-1 and IV-4-2:

[0202]

[0203] Preferably, the medium according to the invention comprises one or more compounds of formula IVa and / or IVb

[0204]

[0205] in

[0206] R 41 and R 42 each independently of one another represents a straight-chain alkyl, alkoxy, alkenyl, alkoxyalkyl or alkenyloxy group having up to 12 C atoms, and

[0207] express

[0208] Z 4 It represents a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -C4H8- or -CF=CF-.

[0209] Preferred compounds of formula IVa are selected from compounds of formulae IVa-1 to IVa-4:

[0210]

[0211] in

[0212] Alkyl and alkyl* each independently represent a straight-chain alkyl group having 1 to 6 C atoms.

[0213] The medium according to the invention preferably comprises at least one compound of the formula IVa-2.

[0214] Preferred compounds of formula IVb are selected from compounds of formulae IVb-1 to IVb-3:

[0215]

[0216] in

[0217] Alkyl and alkyl* each independently represent a straight-chain alkyl group having 1 to 6 C atoms, and

[0218] Alkenyl and alkenyl* each independently represent straight-chain alkenyl having 2 to 6 C atoms.

[0219] Among the compounds of the formulae IVb-1 to IVb-3, the compound of the formula IVb-2 is particularly preferred.

[0220] Particularly preferred compounds of formula IVb are selected from the following compounds:

[0221]

[0222] The medium according to the invention particularly preferably comprises the compound IVb-2-3.

[0223] Preferably, the medium according to the invention comprises one or more compounds of formula V

[0224]

[0225] in

[0226] R 51 、R 52 represents an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkoxyalkyl group having 2 to 7 carbon atoms, an alkenyl group or an alkenyloxy group,

[0227] Express the same or differently

[0228]

[0229]

[0230] Z 51 , Z 52 Each independently represents -CH2-CH2-, -CH2-O-, -CH=CH-, -C≡C-, -COO- or a single bond, and

[0231] n is 1 or 2.

[0232] The compound of formula V is preferably selected from the compounds of formulae V-1 to V-17:

[0233]

[0234]

[0235] where R 51 and R 52 has the meaning indicated above for formula V.

[0236] R 51 and R 52 Preferably, each independently of one another represents straight-chain alkyl having 1 to 7 C atoms or alkenyl having 2 to 7 C atoms.

[0237] Preferred media contain one or more compounds of the formula V-1, V-3, V-4, V-6, V-7, V-10, V-11, V-12, V-14, V-15, V-16 and / or V- 17. Very preferably, the media contain one or more compounds of the formula V-6, V-10, V-16 and / or V-17, in particular V-6, V-10 and V-17.

[0238] In a preferred embodiment of the invention, the medium additionally comprises one or more compounds of the formulae VI-1 to VI-9

[0239]

[0240]

[0241] in

[0242] R 6 Each independently has the following characteristics for R in claim 1 1 One of the meanings indicated, and

[0243] w each independently represents an integer of 1 to 6.

[0244] In a preferred embodiment of the invention, the medium additionally comprises one or more compounds of the formulae VII-1 to VII-21,

[0245]

[0246]

[0247]

[0248]

[0249] in

[0250] R represents a straight-chain alkyl or alkoxy group having 1 to 6 C atoms, (O) represents -O- or a single bond, m is 0, 1, 2, 3, 4, 5 or 6 and n is 0, 1, 2, 3 or 4, and

[0251] R preferably represents a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, or a pentoxy group.

[0252] Particularly preferred are compounds of the formulae VII-1, VII-2, VII-4, VII-20, and VII-21. In these compounds, R preferably represents an alkyl group and, in addition, an alkoxy group, each having 1 to 5 carbon atoms. In the compound of the formula VII-20, R preferably represents an alkyl group or an alkenyl group, in particular an alkyl group. In the compound of the formula VII-21, R preferably represents an alkyl group.

[0253] Preferably, the medium according to the invention comprises, in addition to the compound of formula LY, one or more compounds having negative dielectric anisotropy, selected from the following formulae YA, YB, YC and YD, B, BA-1 and BA-2:

[0254]

[0255]

[0256] in

[0257] R 2A 、R 2B 、R 2C and R 2D each independently of one another represents H, alkyl or alkenyl having up to 15 C atoms, which is unsubstituted, monosubstituted by CN or CF3 or at least monosubstituted by halogen, wherein, in addition, one or more CH2 groups in these radicals may be replaced by -O-, -S-,

[0258] -C≡C-, -CF2O-, -OCF2-, -OC-O- or -O-CO- are replaced in such a way that the O atoms are not directly connected to each other,

[0259] L 1 To L 4 each independently represents F, Cl, CF3 or CHF2,

[0260] Y represents H, F, Cl, CF3, CHF2 or CH3, preferably H or CH3, very preferably H,

[0261] Z 2 , Z 2B and Z 2D each independently of one another represents a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF- or -CH=CHCH2O-,

[0262] P represents 0, 1 or 2,

[0263] q represents 0 or 1, and

[0264] v means 1, 2, 3, 4, 5 or 6,

[0265] wherein compounds of formula LY are excluded from formula YD.

[0266] Preferred compounds of formula YA, YB, YC and YD are shown below:

[0267]

[0268]

[0269]

[0270]

[0271]

[0272]

[0273]

[0274]

[0275]

[0276]

[0277]

[0278]

[0279] wherein the parameter a is 1 or 2, alkyl and alkyl* each independently represent a straight-chain alkyl radical having 1 to 6 carbon atoms, and alkenyl represents a straight-chain alkenyl radical having 2 to 6 carbon atoms, and (O) represents an oxygen atom or a single bond. Alkenyl preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0280] Particularly preferred mixtures according to the invention comprise one or more compounds of the formulae YA-2, YA-8, YA-10, YA-16, YA-18, YA-40, YA-41, YA-42, YA-43, YB-2, YB-10, YB-16, YC-1, YD-4 and YD-10.

[0281] The proportion of the compounds of the formulae YA and / or YB in the mixture as a whole is preferably at least 20% by weight.

[0282] Preferred media according to the invention comprise at least one compound of formula YC-1,

[0283]

[0284] wherein alkyl and alkyl* have the abovementioned meanings, preferably in amounts of <5% by weight, in particular >3% by weight.

[0285] In particular, the medium comprises one or more compounds of formula YA-2 selected from the following subformulae:

[0286]

[0287]

[0288] Alternatively, it is preferred that the medium comprises, in addition to the compounds of the formulae YA-2-1 to YA-2-5, one or more compounds of the formulae YA-2a-1 to YA-2a-5:

[0289]

[0290] In particular, the medium comprises one or more compounds of formula YA-10 selected from the following subformulae:

[0291]

[0292] Alternatively, it is preferred that the medium contains, in addition to the compounds of the formulae YA-10-1 to YA-10-5, one or more compounds of the formulae YA-10a-1 to YA-10a-5:

[0293]

[0294]

[0295] In particular, the medium comprises one or more compounds of formula YB-10 selected from the following subformulae:

[0296]

[0297] Alternatively, it is preferred that the medium contains, in addition to the compounds of the formulae YB-10-1 to YB-10-5, one or more compounds of the formulae YB-10a-1 to YB-10a-5:

[0298]

[0299] The medium according to the invention optionally comprises one or more compounds of formula B

[0300]

[0301] in,

[0302] R 11 and R 12each independently of one another represents H, alkyl or alkoxy having 1 to 15 C atoms, wherein in addition one or more CH2 groups in these radicals may each independently of one another be -C≡C-, -CF2O-, -OCF2-, -CH=CH-, are replaced by -O-, -CO-O- or -O-CO- in such a way that the O atoms are not directly connected to each other, and wherein one or more H atoms may be replaced by halogen,

[0303] A 1 Represented independently of each other at each occurrence

[0304] a) 1,4-cyclohexenyl or 1,4-cyclohexylene, in which one or two non-adjacent CH2 groups may be replaced by -O- or -S-,

[0305] b) 1,4-phenylene, in which one or both CH groups may be replaced by N, or

[0306] c) a radical selected from the group consisting of 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,

[0307] wherein the groups a), b) and c) may be mono- or polysubstituted by halogen atoms,

[0308] n represents 0, 1 or 2, preferably 0 or 1,

[0309] Z 1 represents, independently of one another at each occurrence, -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

[0310] L 11 and L 12 each independently of one another represents F, Cl, CF3 or CHF2, preferably H or F, most preferably F, and

[0311] W represents O or S.

[0312] The compound of formula B is preferably selected from the compounds of formula B-1 and / or B-2

[0313]

[0314] The groups occurring therein have the same meanings as given above in formula B and are preferably

[0315] R 11 and R 12 each independently of one another is alkyl, alkenyl or alkoxy having up to 15 C atoms, more preferably one or two of them represents alkoxy, and

[0316] L 11 and L 12 Each preferably represents F.

[0317] Preferably, the compound of formula B-1 is selected from the compounds of formulae B-1-1 to B-1-11, preferably the compound of formula B-1-6,

[0318]

[0319]

[0320] in

[0321] Alkyl and alkyl* each independently represent a straight-chain alkyl group having 1 to 6 C atoms, alkenyl and alkenyl* each independently represent a straight-chain alkenyl group having 2 to 6 C atoms, alkoxy and alkoxy* each independently represent a straight-chain alkoxy group having 1 to 6 C atoms, and L 11 and L 12 Each independently represents F or Cl, preferably both are F.

[0322] Preferably, the compound of formula B-2 is selected from the compounds of formulae B-2-1 to B-2-10, preferably formula B-2-6,

[0323]

[0324]

[0325] in

[0326] Alkyl and alkyl* each independently represent a straight-chain alkyl group having 1 to 6 C atoms, alkenyl and alkenyl* each independently represent a straight-chain alkenyl group having 2 to 6 C atoms, alkoxy and alkoxy* each independently represent a straight-chain alkoxy group having 1 to 6 C atoms, and L 1 and L 2 Each independently represents F or Cl, preferably both are F.

[0327] Optionally, the medium contains one or more compounds of formula BA-1 and / or BA-2

[0328]

[0329] Among them L 11 and L 12 has the same meaning as given above in formula B, (O) represents O or a single bond,

[0330] R IIIA represents an alkyl or alkenyl group having up to 7 C atoms or a group Cy-C m H 2m+1 -,

[0331] m and n, identically or differently, are 0, 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, very preferably 1,

[0332] Cy denotes a cycloaliphatic radical having 3, 4 or 5 ring atoms, which is optionally substituted by alkyl or alkenyl each having up to 3 C atoms, or by halogen or CN, and preferably denotes cyclopropyl, cyclobutyl or cyclopentyl.

[0333] Alternatively or in addition to the compound of formula B, preferably alternatively, the medium comprises a compound of formula BA-1 and / or BA-2.

[0334] Very preferred compounds of formula BA-1 and BA-2 are as follows:

[0335]

[0336]

[0337] wherein alkoxy represents a straight-chain alkoxy radical having 1 to 6 C atoms, or alternatively -(CH2) n F, wherein n is 2, 3, 4 or 5, preferably C2H4F.

[0338] In a preferred embodiment of the present invention, the medium comprises one or more compounds of formula B-3

[0339]

[0340] in

[0341] R 11 and R 12 Identically or differently represent H, alkyl or alkoxy radicals having 1 to 15 C atoms, wherein one or more CH2 radicals in these radicals are optionally, independently of one another, replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, —O—, —CO—O— or —O—CO— is replaced in such a way that the O atoms are not directly connected to one another, and wherein furthermore one or more H atoms may be replaced by halogen.

[0342] The compound of formula B-3 is preferably selected from the compounds of formulae B-3-1 to B-3-10:

[0343]

[0344]

[0345]

[0346] where R 12 represents alkyl having 1 to 7 C atoms, preferably ethyl, n-propyl or n-butyl, or alternatively represents cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl, or alternatively -(CH2) n F, wherein n is 2, 3, 4 or 5, preferably C2H4F.

[0347] In a preferred embodiment of the invention, the medium comprises one or more compounds of formulae B-4 to B-6, preferably formula B-5,

[0348]

[0349] The radicals occurring therein have the meanings given above, R 11 Preferably represents a straight chain alkyl group, R 12 Preferably denotes alkoxy, each having 1 to 7 C atoms.

[0350] In a preferred embodiment, the medium comprises one or more compounds of formula I selected from the group consisting of compounds of formulae B-7 to B-9, preferably formula B-8,

[0351]

[0352]

[0353] where the parameters have the meanings given above, R 11 Preferably represents a straight chain alkyl group, R 12 Preferably denotes alkoxy, each having 1 to 7 C atoms.

[0354] Further preferred embodiments are listed below:

[0355] a) Liquid-crystalline medium comprising at least one compound of the formulae Z-1 to Z-7

[0356]

[0357]

[0358] wherein R and alkyl have the meanings indicated above for formula B.

[0359] b) liquid-crystalline media preferred according to the invention comprise one or more substances containing tetrahydronaphthyl or naphthyl units, for example compounds of the formulae N-1 to N-5,

[0360]

[0361] where R 1N and R 2N Each independently has a 2A The meanings shown in the preceding sentences preferably represent straight-chain alkyl, straight-chain alkoxy or straight-chain alkenyl, and

[0362] Z 1 and Z 2 Each independently represents -C2H4-, -CH=CH-, -(CH2)4-, -(CH2)3O-, -O(CH2)3-, -CH=CHC H2CH2-, -CH2CH2CH=CH-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF-, -CF=CH-, -CH=CF-, -CF2O-, -OCF2-, -CH2- or a single bond.

[0363] c) preferably a mixture comprising one or more compounds selected from the group consisting of difluorodibenzochroman compounds of formula BC, chroman compounds of formula CR and fluorinated phenanthrene compounds of formulae PH-1 and PH-2,

[0364]

[0365] in

[0366] R B1 、R B2 、R CR1 、R CR2 、R 1 、R 2 Each independently has R 2A The meaning of is. c is 0, 1 or 2. R 1 and R 2 Preferably, independently of one another, they represent alkyl or alkoxy radicals having 1 to 6 C atoms.

[0367] Particularly preferred compounds of formula BC and CR are compounds BC-1 to BC-7 and CR-1 to CR-5,

[0368]

[0369]

[0370] in

[0371] Alkyl and alkyl* each independently represent a straight-chain alkyl group having 1 to 6 C atoms, and

[0372] Alkenyl and alkenyl* each independently represent a straight-chain alkenyl group having 2 to 6 C atoms.

[0373] Very particular preference is given to mixtures comprising one, two or three compounds of the formulae BC-2, BF-1 and / or BF-2.

[0374] d) Preferred mixtures comprise one or more indane compounds of the formula In,

[0375]

[0376] in

[0377] R 11 、R 12 and R 13 each independently of one another represents a straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl radical having 1 to 6 C atoms,

[0378] R 12 and R 13 Alternatively represents halogen, preferably F,

[0379] express

[0380]

[0381] i represents 0, 1, or 2.

[0382] Preferred compounds of formula In are the following compounds of formulae In-1 to In-16:

[0383]

[0384]

[0385]

[0386] Particular preference is given to compounds of the formulae In-1, In-2, In-3 and In-4.

[0387] e) Preferred mixtures additionally comprise one or more compounds of the formulae L-1 to L-8,

[0388]

[0389] in

[0390] R, R 1 and R 2 Each independently has the above formula YA for R 2A The indicated meanings, and alkyl represents an alkyl radical having 1 to 6 C atoms. The parameter s represents 1 or 2.

[0391] The compounds of the formulae L-1 to L-9 are preferably used in a concentration of 5 to 15% by weight, in particular 5 to 12% by weight and very particularly preferably 8 to 10% by weight.

[0392] f) Preferred mixtures additionally comprise one or more compounds of the formula IIA-Y

[0393]

[0394] where R 11 and R 12 With the above formula IIA for R 2A One of the meanings given and L 1 and L 2 represents F or Cl, identically or differently.

[0395] Preferred compounds of formula YA-Y are selected from the following subformulas

[0396]

[0397]

[0398] wherein Alkyl and Alkyl* each independently represent a straight-chain alkyl group having 1 to 6 carbon atoms, Alkoxy represents a straight-chain alkoxy group having 1 to 6 carbon atoms, Alkenyl and Alkenyl* each independently represent a straight-chain alkenyl group having 2 to 6 carbon atoms, and O represents an oxygen atom or a single bond. Alkenyl and Alkenyl* preferably represent CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0399] Particularly preferred compounds of formula YA-Y are selected from the following subformulae:

[0400]

[0401]

[0402] wherein Alkoxy and Alkoxy* have the meanings defined above, preferably representing methoxy, ethoxy, n-propoxy, n-butoxy or n-pentoxy.

[0403] Preferably, the medium according to the invention comprises a stabilizer chosen from the compounds of formulae ST-1 to ST-19.

[0404]

[0405]

[0406]

[0407]

[0408] in

[0409] R ST represents H, alkyl or alkoxy having 1 to 15 C atoms, wherein, in addition, one or more CH2 groups in these groups can each independently of one another be replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O-, -O-CO- are replaced in such a way that the O atoms are not directly connected to one another, and wherein one or more additional H atoms may be replaced by halogen,

[0410] express

[0411]

[0412]

[0413] Z ST Each independently represents -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,

[0414] L 1 and L 2 Each independently represents F, Cl, CF3 or CHF2,

[0415] p means 1 or 2,

[0416] q represents 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0417] Among the compounds of formula ST, compounds of formula

[0418]

[0419] wherein n=1, 2, 3, 4, 5, 6 or 7, preferably n=1 or 7

[0420]

[0421] wherein n=1, 2, 3, 4, 5, 6 or 7, preferably n=3

[0422]

[0423] wherein n=1, 2, 3, 4, 5, 6 or 7, preferably n=3

[0424]

[0425]

[0426] In the compounds of formulae ST-3a and ST-3b, n preferably represents 3. In the compound of formula ST-2a, n preferably represents 7.

[0427] Very particularly preferred mixtures according to the invention comprise one or more stabilizers selected from the group consisting of compounds of the formulae ST-2a-1, ST-3a-1, ST-3b-1, ST-8-1, ST-9-1 and ST-12:

[0428]

[0429]

[0430] The compounds of the formulae ST-1 to ST-19 are preferably each present in the liquid-crystal mixture according to the invention in an amount of 0.005 to 0.5%, based on the mixture.

[0431] If the mixture according to the invention comprises two or more compounds selected from the formulae ST-1 to ST-18, the concentration is correspondingly increased to 0.01-1% in the case of two compounds, based on the mixture.

[0432] However, the total proportion of compounds of the formulae ST-1 to ST-18, based on the mixture according to the invention, should not exceed 2%.

[0433] In another preferred embodiment of the present invention, the liquid-crystalline medium additionally comprises one or more polymerizable compounds. The polymerizable compounds are preferably selected from the group consisting of:

[0434] R a -B 1 -(Z b -B 2 ) m -R bM

[0435] where the individual radicals have the following meanings, identically or differently on each occurrence and independently of one another:

[0436] R a and R b is P, P-Sp-, H, F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, SF5 or a straight-chain or branched alkyl radical having 1 to 25 C atoms, wherein, in addition, one or more non-adjacent CH2 groups may each be replaced independently of one another by -C(R 0 )=C(R 00 )-、-C≡C-、-N(R 00 )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that the O and / or S atoms are not directly connected to each other, and, wherein, in addition, one or more H atoms may be replaced by F, Cl, Br, I, CN, P or P-Sp-, wherein if B 1 and / or B 2 Contains saturated C atoms, then R a and / or R b It can also represent a group spiro-bonded to the saturated C atom,

[0437] The group R a and R b At least one of represents or contains a group P or P-Sp-,

[0438] P is a polymerizable group,

[0439] Sp is a spacer group or a single bond,

[0440] B 1 and B 2 is an aromatic, heteroaromatic, alicyclic or heterocyclic radical having preferably 4 to 25 ring atoms, which may also contain fused rings, and which is unsubstituted or mono- or polysubstituted by L,

[0441] Z b is -O-, -S-, -CO-, -CO-O-, -OCO-, -O-CO-O-, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -(CH2) n1 -, -CF2CH2-, -CH2CF2-, -(CF2) n1 -, -CH=CH-, -CF=CF-, -C≡C-, -CH=CH-COO-, -OCO-CH=CH-, CR 0R 00 or single key,

[0442] R 0 and R 00 each independently of one another represents H or an alkyl group having 1 to 12 C atoms,

[0443] m represents 0, 1, 2, 3 or 4,

[0444] n1 means 1, 2, 3 or 4,

[0445] L is P, P-Sp-, OH, CH2OH, F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, -C(=O)N(R x )2、-C(=O)Y 1 、-C(=O)R x 、-N(R x )2, optionally substituted silyl, optionally substituted aryl having 6 to 20 C atoms, or linear or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, where, in addition, one or more H atoms may be replaced by F, Cl, P or P-Sp-,

[0446] P and Sp have the meanings stated above,

[0447] Y 1 represents halogen,

[0448] R x represents P, P-Sp-, H, halogen, straight-chain, branched or cyclic alkyl having 1 to 25 C atoms, where, in addition, one or more non-adjacent CH2 groups can be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that the O and / or S atoms are not directly connected to one another, where, in addition, one or more H atoms can be replaced by F, Cl, P or P-Sp-, optionally substituted aryl or aryloxy having 6 to 40 C atoms or optionally substituted heteroaryl or heteroaryloxy having 2 to 40 C atoms.

[0449] Particularly preferred compounds of formula I are those in which B 1 and B 2each independently of one another represents 1,4-phenylene, 1,3-phenylene, naphthalene-1,4-diyl, naphthalene-2,6-diyl, phenanthrene-2,7-diyl, 9,10-dihydro-phenanthrene-2,7-diyl, anthracene-2,7-diyl, fluorene-2,7-diyl, coumarin, flavonoid, where, in addition, one or more CH groups in these groups may be replaced by N, cyclohexane-1,4-diyl, where, in addition, one or more non-adjacent CH2 groups may be replaced by O and / or S, 1, 4-cyclohexenylene, bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, piperidine-1,4-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, indane-2,5-diyl or octahydro-4,7-methanoindane-2,5-diyl, all of which may be unsubstituted or mono- or polysubstituted by L as defined above.

[0450] Particularly preferred compounds of formula M are those wherein B 1 and B 2 Those which each independently of one another represent 1,4-phenylene, 1,3-phenylene, naphthalene-1,4-diyl or naphthalene-2,6-diyl.

[0451] Very preferred compounds of formula M are selected from the following formulae:

[0452]

[0453]

[0454]

[0455]

[0456]

[0457]

[0458] where the individual radicals have the following meanings, identically or differently on each occurrence and independently of one another:

[0459] P 1 、P 2 、P 3 is a polymerizable group, preferably selected from vinyloxy, acrylate, methacrylate, fluoroacrylate, chloropropionate, oxetane or epoxy,

[0460] Sp 1 、Sp 2 and Sp 3 is a single bond or a spacer group, wherein, in addition, the group P1 -Sp 1 -、P 2 -Sp 2 - and P 3 -Sp 3 - can also represent one or more R aa , provided that there is a group P 1 -Sp 1 -、P 2 -Sp 2 and P 3 -Sp 3 - at least one of them is different from R aa , preferably represents -(CH2) p1 -、-(CH2) p1 -O-, -(CH2) p1 -CO-O- or (CH2) p1 -O-CO-O-, wherein p1 is an integer from 1 to 12.

[0461] R aa represents H, F, Cl, CN or a straight-chain or branched alkyl radical having 1 to 25 C atoms, wherein in addition, one or more non-adjacent CH2 groups may be replaced independently of one another by -C(R 0 )=C(R 00 )-、-C≡C-、-N(R 0 )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that the O and / or S atoms are not directly connected to each other, and wherein, in addition, one or more H atoms may be replaced by F, Cl, CN or P 1 -Sp 1 - alternatively, particularly preferably a linear or branched, optionally monofluorinated or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy radical 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,

[0462] R 0 , R 00 is H or an alkyl group having 1 to 12 C atoms,

[0463] R y and R z is H, F, CH3 or CF3,

[0464] X 1 、X 2 、X 3 is -CO-O-, -O-CO- or a single bond,

[0465] ZM1 It is -O-, -CO-, -C(R y R z )- or -CF2CF2-,

[0466] Z M2 , Z M3 is -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CF2O-, -OCF2- or -(CH2) n -, where n is 2, 3, or 4,

[0467] L is F, Cl, CN or linear or branched, optionally monofluorinated or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms,

[0468] L', L" are H, F or Cl,

[0469] r is 0, 1, 2, 3, or 4,

[0470] s is 0, 1, 2, or 3,

[0471] t is 0, 1, or 2,

[0472] x is either 0 or 1.

[0473] Particularly preferred are compounds of formulae M2 and M13.

[0474] Further preferred are the trireactive compounds M15 to M31, in particular M17, M18, M19, M22, M23, M24, M25, M30 and M31.

[0475] In the compounds of formulae M1 to M31, the group wherein L has one of the meanings indicated above and r represents 0, 1, 2, 3 or 4, in particular

[0476]

[0477] wherein L has, identically or differently on each occurrence, one of the meanings given above and below and is preferably F, Cl, CN, NO2, CH3, C2H5, C(CH3)3, CH(CH3)2, CH2CH(CH3)C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5 or P-Sp-, very preferably F, Cl, CN, CH3, C2H5, OCH3, COCH3, OCF3 or P-Sp-, more preferably F, Cl, CH3, OCH3, COCH3 or OCF3 and in particular F or CH3.

[0478] Preferred compounds of formula M1 to M31 are those wherein P 1 、P 2 and P 3 Those compounds representing acrylate, methacrylate, oxetanyl or epoxy groups, very preferably acrylate or methacrylate groups.

[0479] Further preferred compounds of formula M1 to M31 are those wherein Sp 1 、Sp 2 and Sp 3 Those compounds that have single bonds.

[0480] Further preferred compounds of formula M1 to M31 are those wherein Sp 1 、Sp 2 and Sp 3 One of the bonds is a single bond and Sp 1 、Sp 2 and Sp 3 The other one is different from those compounds with single bonds.

[0481] Further preferred compounds of the formulae M1 to M31 are those in which the radical Sp which is different from a single bond is 1 、Sp 2 and Sp 3 Represents -(CH2) s1 -X"-, wherein s1 is an integer from 1 to 6, preferably 2, 3, 4 or 5, and X" is a linker to the benzene ring and is -O-, -O-CO-, -CO-O, -O-CO-O- or a single bond.

[0482] Particular preference is given to liquid-crystalline media which comprise one, two or three polymerizable compounds of the formula M, preferably selected from the formulae M1 to M31.

[0483] It is further preferred that the liquid-crystalline media according to the invention comprise one or more polymerizable compounds selected from Table E below.

[0484] Preferably, the proportion of polymerizable compounds in the liquid-crystalline medium is 0.01-5%, very preferably 0.05-1%, most preferably 0.1-0.5%, said polymerizable compounds preferably being selected from the group consisting of formula M and table E.

[0485] It has been observed that the addition of one or more polymerizable compounds, such as those selected from Formula M and Table E, to a liquid crystal medium results in advantageous properties, such as a fast response time. Such liquid crystal media are particularly suitable for PSA displays, where they exhibit low image viscosity, rapid and complete polymerization, rapid development of low pretilt angles that are stable after UV exposure, high reliability, high VHR values ​​after UV exposure, and high birefringence. By appropriately selecting the polymerizable compound, the absorption of the liquid crystal medium at longer UV wavelengths can be increased, allowing the use of such longer UV wavelengths for polymerization, which is advantageous for display manufacturing methods.

[0486] The polymerizable group P is suitable for polymerization reactions, such as free radical or ionic chain polymerization, polyaddition or polycondensation, or for polymer-analogous reactions, such as addition or condensation on the polymer backbone. Particularly preferred are groups for chain polymerization, in particular those containing a C=C double bond or a -C≡C- triple bond, and groups suitable for ring-opening polymerization, such as, for example, oxetanyl or epoxy.

[0487] The preferred P group is selected from the group consisting of: CH2=CW 1 -CO-O-, CH2=CW 1 -CO-, CH2=CW 2 -(O) k3 -、CW 1 =CH-CO-(O) k3 -、CW 1 =CH-CO-NH-, CH2=CW 1 -CO-NH-, CH3-CH=CH-O-, (CH2=CH)2CH-OCO-, (CH2=CH-CH2)2CH-OCO-, (CH2=CH)2CH-O-, (CH2=CH-CH2)2N-, (CH2=CH-CH2)2N-CO-, HO-CW 2 W 3 -、HS-CW 2 W 3 -、HW 2 N-、HO-CW 2 W 3 -NH-、CH2=CW 1 -CO-NH-, CH2=CH-(COO) k1 -Phe-(O) k2 -、CH2=CH-(CO) k1 -Phe-(O) k2 -, Phe-CH=CH-, HOOC-, OCN- and W 4 W 5 W 6 Si-, where W1 represents H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH3, W 2 and W 3 each independently of one another represents H or an alkyl group having 1 to 5 carbon atoms, in particular H, methyl, ethyl or n-propyl, W 4 、W 5 and W 6 each independently represents Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W 7 and W 8 Each independently of one another represents H, Cl or an alkyl group having 1 to 5 C atoms, Phe represents 1,4-phenylene, which is optionally substituted by one or more groups L as defined above, said group L being not P-Sp-, k1, k2 and k3 each independently of one another represent 0 or 1, k3 preferably represents 1, and k4 represents an integer from 1 to 10.

[0488] Very preferred P groups are selected from the group consisting of: CH2=CW 1 -CO-O-, CH2=CW 1 -CO-, CH2=CW 2 -O-、CH2=CW 2 -、CW 1 =CH-CO-(O) k3 -、CW 1 =CH-CO-NH-, CH2=CW 1 -CO-NH-, (CH2=CH)2CH-OCO-, (CH2=CH-CH2)2CH-OCO-, (CH2=CH)2CH-O-, (CH2=CH-CH2)2N-, (CH2=CH-CH2)2N-CO-, CH2=CW 1 -CO-NH-, CH2=CH-(COO) k1 -Phe-(O) k2 -、CH2=CH-(CO) k1 -Phe-(O) k2 -, Phe-CH=CH- and W 4 W 5 W 6 Si-, where W 1 represents H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH3, W 2 and W 3 each independently of one another represents H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W 4 、W5 and W 6 each independently represents Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W 7 and W 8 Each independently represents H, Cl or an alkyl group having 1 to 5 C atoms, Phe represents 1,4-phenylene, k1, k2 and k3 each independently represent 0 or 1, k3 preferably represents 1, and k4 represents an integer of 1-10.

[0489] Very particularly preferred P groups are selected from the group consisting of: CH2=CW 1 -CO-O-, in particular CH2=CH-CO-O-, CH2=C(CH3)-CO-O- and CH2=CF-CO-O-, as well as CH2=CH-O-, (CH2=CH)2CH-O-CO-, (CH2=CH)2CH-O-,

[0490] Further preferred polymerizable groups P are selected from the group consisting of vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetanyl and epoxy, most preferably from acrylate and methacrylate.

[0491] If Sp is different from a single bond, it is preferably of the formula Sp"-X", so that the corresponding group P-Sp- corresponds to the formula P-Sp"-X", in which

[0492] Sp" denotes an alkylene radical having 1 to 20 C atoms, preferably 1 to 12 C atoms, which is optionally monosubstituted or polysubstituted by F, Cl, Br, I or CN, and wherein, in addition, one or more non-adjacent CH2 groups may each be replaced independently of one another by -O-, -S-, -NH-, -N(R 0 )-,-Si(R 0 R 00 )-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -S-CO-, -CO-S-, -N(R 00 )-CO-O-,-O-CO-N(R 0 )-,-N(R 0 )-CO-N(R 00 )-, -CH=CH- or -C≡C- are substituted in such a way that the O and / or S atoms are not directly bonded to each other,

[0493] X" means -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CO-N(R 0 )-,N(R 0 )-CO-,-N(R 0)-CO-N(R 00 )-, -OCH2-, -CH2O-, -SCH2-, -CH2S-, CF2O-, -OCF2-, -CF2S-, -SCF2-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=N-, -N=CH-, -N=N-, -CH=CR 0 -,-CY 2 =CY 3 -, -C≡C-, -CH=CH-CO-O-, -O-CO-CH=CH- or a single bond,

[0494] R 0 and R 00 each independently of one another represents H or an alkyl group having 1 to 20 C atoms, and

[0495] Y 2 and Y 3 Each independently represents H, F, Cl or CN.

[0496] X" is preferably -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR 0 -、-NR 0 -CO-、-NR 0 -CO-NR 00 - or single key.

[0497] Typical spacer groups Sp and -Sp"-X" are, for example, -(CH2) p1 -、-(CH2CH2O) q1 -CH2CH2-、-CH2CH2-S-CH2CH2-、-CH2CH2-NH-CH2CH2- or -(SiR 0 R 00 -O) p1 -, where p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R 0 and R 00 Has the above meaning.

[0498] Particularly preferred groups Sp and -Sp"-X" are -(CH2) p1 -, -(CH2) p1 -O-, -(CH2) p1 -O-CO-, -(CH2) p1 -CO-O-, -(CH2) p1 -O-CO-O-, wherein p1 and q1 have the above meanings.

[0499] Particularly preferred radicals Sp" are in each case linear ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methylimino-ethylene, 1-methylalkylene, vinylene, propenylene and butenylene.

[0500] To produce PSA displays, the polymerizable compounds contained in the liquid-crystalline medium are polymerized or crosslinked (if one compound contains two or more polymerizable groups) by in situ polymerization in the liquid-crystalline medium between the substrates of the LC display, optionally while applying a voltage to the electrodes.

[0501] The structure of the PSA display according to the invention corresponds to the usual geometries of PSA displays, as described in the prior art cited at the outset. Geometries without protrusions are preferred, in particular those in which the electrodes on the color filter side are unstructured and only the electrodes on the TFT side have grooves. Particularly suitable and preferred electrode structures for PS-VA displays are described, for example, in US 2006 / 0066793 A1.

[0502] The combination of the compounds of the above-mentioned preferred embodiments with the above-mentioned polymerized compounds leads in the liquid-crystalline media according to the invention to low threshold voltages, low rotational viscosities and very good low-temperature stability, together with constantly high bright spots and high VHR values.

[0503] Liquid-crystalline media containing polymerizable compounds are used to rapidly establish particularly low pretilt angles in PSA displays. In particular, the LC media in PSA displays exhibit significantly shortened response times, in particular for grayscale response times, compared to media from the prior art.

[0504] In a further preferred embodiment, the medium according to the invention comprises the following compounds, where the acronyms are explained in Table D below:

[0505] - one, two or more compounds of formula I, their total concentration is in the range of 1% to 10%, preferably 2% to 9%, particularly preferably 3% to 8%;

[0506] - one or more compounds of the formula LY, the total concentration of which is in the range of 2% to 10%, preferably 4% to 8%, particularly preferably 5% to 7%;

[0507] - one or more compounds of formula II, preferably compounds of formula II-1 and / or II-3, in particular compounds of subformulae II-1a-1 and / or II-1f-1 and / or II-1g-1 and / or II-1h-1 and / or II-3d-1, in a total concentration range of 3% to 20%, preferably 5% to 15%, particularly preferably 7% to 11%;

[0508] and / or

[0509] - one or more compounds of formula III, whose total concentration ranges from 2% to 15%, preferably from 3% to 12%, more preferably from 4% to 10%, very preferably from 5% to 8%, preferably selected from compounds of formula III-2, more preferably formula III-2i and / or III-2l and / or III-2m, very preferably formula III-2i-3 and / or III-2l-3 and / or III-2m-1, wherein the concentration of one or more compounds of formula III-2m-1 is preferably 1% or less;

[0510] and / or

[0511] - one or more compounds of formula IV-3, in a total concentration ranging from 40% to 50%, very preferably selected from the compounds of formulae IV-3-1 to IV-3-6, in particular compounds of formulae IV-3-2 and / or IV-3-6;

[0512] and / or

[0513] - 2% to 7%, preferably 3% to 6% of compound CC-3-2V1 or CC-4-V1, preferably compound CC-4-V1;

[0514] and / or

[0515] - one or more compounds of the formula IVb, preferably of the formula VIb-2, very preferably of the formula IVb-2-3, preferably in a total concentration in the range of 0.5% to 8%, more preferably 1% to 4%, in particular 2% to 3%;

[0516] - 10% to 30% in total of one or more compounds of formula V, preferably selected from compounds V-1, V-3, V-4, V-6, V-7, V-10, V-11, V-12, V-14, V-15, V-16 and V-17; more preferably, the medium comprises one or more compounds of formula V-6, V-10, V-16 and / or V-17, very preferably V-6 and V-10 and V-17; most preferably formula CCP-Vn and / or CCP-n V-m and / or CCP-Vn-m and / or CCVC-n-Vm and / or CPGP-nm, in particular of the formula CCP-Vn and / or CCP-V2-n; and very particularly compounds selected from the group consisting of the formulae CCP-V-1 and CCP-V2-1, in a total concentration ranging from 10% to 30%, preferably from 12% to 25%, in particular from 16% to 22%, with a further 2% to 8% of compounds CCVC-n-Vm, preferably CCVC-3-V;

[0517] A highly preferred medium comprises

[0518] - one or more compounds of formula II-1g, II-1f and II-3d, preferably compounds of formula II-1g-1, II-1f-1 and II-3d-1, preferably in a total concentration in the range of 5% to 20%, more preferably 7% to 18%, very preferably 8% to 16%, in particular 9% to 14%;

[0519] - Compounds of formula V-17, very preferably compounds of formula CPGP-5-2, in a total concentration ranging from 0.1% to 5%, more preferably from 0.5% to 3%, in particular from 0.8% to 2% or to 1.5%.

[0520] The liquid-crystalline media according to the invention enable a significant broadening of the available parameter space. The achievable combination of clearing point, low-temperature viscosity, thermal and UV stability and high optical anisotropy is far superior to previous materials of the prior art.

[0521] The liquid crystal media according to the present invention allow a rotational viscosity γ1 of ≤ 100 mPa·s, particularly preferably ≤ 90 mPa·s, to be achieved while maintaining a nematic phase at temperatures as low as -20°C, preferably as low as -30°C, particularly preferably as low as -40°C, and a clearing point of ≥ 85°C, preferably ≥ 95°C. This enables excellent MLC displays with fast response times to be obtained. The rotational viscosity is measured at 20°C.

[0522] The dielectric anisotropy Δε of the liquid-crystal media according to the invention at 20° C. and 1 kHz is preferably ≧+1.5, preferably in the range from +1.5 to +8, more preferably from 2.0 to 7.0, very preferably from 3.0 to 5.0 and particularly preferably from 3.8 to 4.3.

[0523] The birefringence Δn of the liquid-crystalline media according to the invention at 20° C. is preferably from 0.080 to 0.110, very preferably from 0.090 to 0.100, in particular from 0.092 to 0.097.

[0524] In one embodiment, the birefringence Δn of the liquid-crystalline media according to the invention at 20° C. is preferably in the range from 0.091 to 0.093.

[0525] The rotational viscosity γ1 of the liquid-crystal media according to the invention is preferably ≤100 mPa·s, more preferably ≤90 mPa·s and very preferably ≤85 mPa·s.

[0526] The ratio γ1 / K of the liquid-crystal medium according to the invention 11 (where γ1 is the rotational viscosity γ1, and K 11 is the elastic constant of flexural deformation) is preferably ≤5.5 mPa·s / pN.

[0527] The nematic phase range of the liquid-crystalline media according to the invention preferably has a width of at least 90° C., more preferably at least 100° C. and in particular at least 110° C. This range preferably extends from −25° C. to +80° C.

[0528] Herein, the structures of the mesogenic compounds are indicated with the aid of abbreviations, also referred to as acronyms. In these acronyms, the chemical formulae are abbreviated as follows using Tables A to C below. All groups C n H 2n+1 、C m H 2m+1 and C l H 2l+1 and C n H 2n-1 、C m H 2m-1 and C l H 2l-1 and alkylene, respectively, each having n, m or 1 carbon atoms, wherein n and m are independently 1, 2, 3, 4, 5, 6 or 7 and 1 is 1, 2 or 3. Table A lists the codes for the ring elements of the core structures of the compounds, while Tables B and C show the linking groups and the terminal groups. Table D shows illustrative structures of the compounds and their respective abbreviations.

[0529] Table A: Ring Elements

[0530]

[0531]

[0532]

[0533] Table B: Linking Groups

[0534]

[0535] Table C: End Groups

[0536]

[0537]

[0538] where n and m each represent an integer, and the three dots "..." are placeholders for other abbreviations from the table.

[0539] Table D

[0540]

[0541]

[0542]

[0543]

[0544]

[0545]

[0546]

[0547]

[0548]

[0549]

[0550]

[0551]

[0552]

[0553]

[0554]

[0555]

[0556]

[0557]

[0558]

[0559]

[0560]

[0561]

[0562]

[0563]

[0564]

[0565]

[0566]

[0567]

[0568]

[0569] In a preferred embodiment of the invention, the medium comprises one or more compounds selected from the group consisting of the compounds of Table D.

[0570] Table E shows preferred chiral dopants for use in the mixtures of the present invention.

[0571] Table E

[0572]

[0573]

[0574]

[0575] Preferably, the medium according to the invention comprises one or more compounds chosen from the compounds of Table E.

[0576] Table F

[0577] Table F shows illustrative reactive mesogenic compounds (RM) that can be used in the LC media according to the present invention.

[0578]

[0579]

[0580]

[0581]

[0582]

[0583]

[0584]

[0585]

[0586]

[0587]

[0588]

[0589]

[0590]

[0591]

[0592]

[0593]

[0594]

[0595]

[0596]

[0597]

[0598]

[0599]

[0600]

[0601] In a preferred embodiment, the mixture according to the invention comprises one or more polymerizable compounds, preferably selected from the group consisting of polymerizable compounds of formulae RM-1 to RM-144. 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-64, RM-74, RM-76, RM-88, RM-102, RM-103, RM-109, RM-117, RM-120, RM-121, RM-122 and RM-145 to RM-153 are particularly preferred.

[0602] Working Examples

[0603] The following examples are intended to illustrate the present invention without limiting the present invention. In the examples, mp means melting point, and T (N,I) Indicates the clearing point of the liquid crystal material in degrees Celsius; In addition: C represents the crystalline solid state, S represents the smectic phase (the index represents the phase type), N represents the nematic state, Ch represents the cholesteric phase, I represents the isotropic phase, T g Indicates the glass transition temperature. The number between the two symbols indicates the transition temperature in degrees Celsius.

[0604] The host mixture used to determine the optical anisotropy Δn of the individual compounds was the commercial mixture ZLI-4792 (Merck KGaA). The dielectric anisotropy Δε was determined using the commercial mixture ZLI-2857. The physical data for the compounds under investigation were obtained from the change in the dielectric constant of the host mixture after adding the compound under investigation and extrapolated to 100% of the compound used. Typically, 10% of the compound under investigation was dissolved in the host mixture, depending on solubility.

[0605] Unless stated otherwise, parts or percentages are given by weight.

[0606] In context:

[0607] V0 represents the threshold voltage at 20°C, capacitive [V],

[0608] n e Indicates the extraordinary refractive index at 20°C and 589nm,

[0609] n o represents the ordinary refractive index at 20°C and 589nm,

[0610] Δn represents the optical anisotropy at 20°C and 589 nm,

[0611] ε ⊥ represents the dielectric polarizability perpendicular to the director at 20°C and 1kHz,

[0612] ε|| represents the dielectric polarizability parallel to the director at 20°C and 1kHz,

[0613] Δε represents the dielectric anisotropy at 20°C and 1 kHz,

[0614] cl.p. or T(N,I) represents the clearing point [℃],

[0615] γ1 represents the rotational viscosity measured at 20°C [mPa·s],

[0616] K1 represents the elastic constant, the “bending” deformation at 20°C [pN],

[0617] K2 represents the elastic constant, the "torsion" deformation at 20°C [pN],

[0618] K3 represents the elastic constant, the "bending" deformation at 20°C [pN], and

[0619] LTS stands for Low Temperature Stability (Nematic Phase) and is determined as specified in a test cell or body.

[0620] Unless expressly stated otherwise, all values ​​indicated in this application for temperature, such as 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) or cl.p., are expressed in degrees Celsius (°C).

[0621] Unless otherwise specified, the term "threshold voltage" in the present invention refers to the capacitance threshold (V0), also known as the Freedericksz threshold. In the embodiment, as usual, the optical threshold can also be expressed as a relative contrast of 10% (V 10 ).

[0622] The display used to measure the capacitance threshold voltage consists of two plane-parallel glass outer plates separated by 20 μm. Each outer plate has an electrode layer on the inner side and an unrubbed polyimide alignment layer on top, which causes homeotropic edge alignment of the liquid crystal molecules.

[0623] The display or test cell used to measure the tilt angle consists of two plane-parallel glass outer plates separated by 4μm. Each glass outer plate has an electrode layer on the inner side and a polyimide alignment layer on top. The two polyimide layers are rubbed antiparallel to each other, resulting in homeotropic edge alignment of the liquid crystal molecules.

[0624] The polymerizable compound is polymerized in the display or test cell by irradiating the display with UV light of a specified intensity for a predetermined time while simultaneously applying a voltage to the display (typically 10 to 30 V AC, 1 kHz). In the Examples, polymerization was performed using a metal halide lamp with an intensity of 100 mW / cm2, unless otherwise indicated. Intensity was measured using a standard meter (Hoenle UV meter high-end with UV sensor).

[0625] The tilt angle is determined using a Mueller matrix polarimeter "AxoScan" from Axometrics. Here, low values ​​(ie large deviations from an angle of 90°) correspond to large tilts.

[0626] Unless otherwise stated, the term "tilt angle" refers to the angle between the LC director and the substrate, and "LC director" refers to the preferred orientation direction of the optical principal axis of the LC molecules in a layer of uniformly oriented LC molecules, which corresponds to their molecular long axis in the case of rod-shaped uniaxial positively birefringent LC molecules.

[0627] Unless otherwise stated, VHR at 20°C (VHR 20 ) and at 100℃(VHR 100 ) in an oven at 4°C for 5 minutes and then measured in a commercially available instrument of the type LCM-1 (00004) from TOYO Corporation, Japan. Unless otherwise indicated, the frequency of the voltage used is in the range of 1 Hz to 60 Hz.

[0628] The accuracy of the VHR measurement depends on the corresponding VHR value. The accuracy decreases with decreasing values. The following table summarizes the commonly observed deviations, by order of magnitude, for values ​​within various amplitude ranges.

[0629]

[0630] The stability to UV irradiation was investigated using a xenon lamp NXE 1500B in a commercially available instrument "Suntest CPS+" from Heraeus, Germany. Unless otherwise specified, the sealed test chamber was irradiated for 2.0 h without additional heating. The irradiation power in the wavelength range of 300 nm to 800 nm was 765 W / m². 2 V. A UV "cut-off" filter with an edge wavelength of 310 nm was used to simulate the so-called windowpane mode. In each series of experiments, at least four test boxes were studied for each condition, and the corresponding results are expressed as the average of the corresponding individual measurements.

[0631] The reduction in voltage holding ratio (ΔVHR) caused by, for example, UV irradiation or LCD backlight exposure is generally determined according to the following equation (1):

[0632] ΔVHR(t)=VHR(t)-VHR(t=0) (1).

[0633] To study the low-temperature stability, also called "LTS", i.e. the stability of the overall LC mixture against spontaneous crystallization of the individual components or the appearance of a smectic phase at low temperatures, several sealed vials, each containing approximately 1 g of material, are stored at one or more given temperatures, typically -10°C, -20°C, -30°C and / or -40°C, and regularly visually inspected for the presence of phase transitions. As soon as the first sample at a given temperature shows a change, the test is stopped until the time of the last inspection, during which no change is observed, which is recorded as the corresponding LTS. The test is run for 1000 h. If no change occurs after 1000 h, the result is "LTS>1000h".

[0634] The ion density from which the resistivity was calculated was measured using a commercially available LC Material Characteristics Measurement System Model 6254 from Toyo Corporation, Japan, using a VHR test cell made of AL 16301 polyimide (JSR Corp., Japan) with a cell gap of 3.2 μm. The measurements were performed after storage in an oven at 60°C or 100°C for 5 minutes.

[0635] The so-called "HTP" represents the helical twisting power (in μm) of an optically active or chiral substance in an LC medium. Unless otherwise stated, the HTP is measured in the commercially available nematic LC host mixture MLD-6260 (Merck KGaA) at 20°C.

[0636] The clearing point was measured using a Mettler Thermosystem FP 900. Optical anisotropy (Δn) was measured using an Abbe-Refraktometer H005 (sodium spectrometer lamp Na 10, 589 nm, 20°C). Dielectric anisotropy (Δε) was measured using an LCR-Meter E4980A / Agilent (G005) at 20°C (ε-parallel cell with JALS 2096-R1). The on-state voltage (V0) was measured using an LCR-Meter E4980A / Agilent (G005) at 20°C (ε-parallel cell with JALS 2096-R1). Rotational viscosity (γ1) was measured using a TOYO LCM-2 (0002) at 20°C (γ1 negative cell with JALS 2096-R1). Elastic constants (K1, flexure) were measured using an LCR-Meter E4980A / Agilent (G005) at 20°C (ε-parallel cell with JALS2096-R1). K3: Elastic constants (K3, bending) were measured using an LCR-Meter E4980A / Agilent (G005) at 20°C (ε-parallel cell with JALS2096-R1).

[0637] Unless otherwise expressly stated, all concentrations in this application are expressed as weight percent and are relative to the respective mixture as a whole, including all solid or liquid crystal components, without solvent. Unless otherwise expressly stated, all physical properties were determined according to "Merck Liquids Crystal, Physical Properties of Liquid Crystals", Status Nov. 1997, Merck KGaA, Germany, and apply to a temperature of 20°C.

[0638] The following examples of mixtures with negative dielectric anisotropy are particularly suitable for liquid-crystal displays having at least one planar alignment layer, such as IPS and FFS displays, in particular UB-FFS (=Ultra Bright FFS), and VA displays. Example

[0639] Nematic mixtures C-1 to C-3, M-1 to M-15 were prepared as follows:

[0640] Comparative mixture C-1

[0641]

[0642]

[0643] Comparative mixture C-2

[0644]

[0645] Comparative mixture C-3

[0646]

[0647]

[0648] Mixture Example M-1

[0649]

[0650]

[0651] Mixture Example M-2

[0652]

[0653] Mixture Example M-3

[0654]

[0655]

[0656] Mixture Example M-4

[0657]

[0658]

[0659] Compounds of formula I contribute to an improvement in LTS at -40°C: Mixture Example M-1 differs from Comparative Mixture C-1 in that it contains 2% of compound CDU-3-F, which leads to an improvement in LTS at -40°C. Surprisingly, increasing the amount of compounds of formula I (CDU-2-F and CDU-3-F) to 4%, 6% or 8% in Mixture Examples M-2, M-3 or M-4, respectively, leads to LTS at -40°C exceeding 1000 hours.

[0660] The medium must contain both compounds of Formula I and Formula LY: Replacing compound CLY-3-O2 in the mixture with a similar compound resulted in a worse LTS. Comparative Example C-2 is very similar to mixtures M-2, M-3, and M-4, but contains compound CCY-3-O2 instead of a compound of Formula Y, such as CLY-3-O2. LTS is reduced from 1000 hours to 120 hours.

[0661] Comparative Example C-3 is very similar to mixtures M-2, M-3 and M-4, but contains the compound CPY-3-O2 instead of a compound of formula Y, such as CLY-3-O2. The LTS is reduced from 1000 hours to 168 hours.

[0662] Mixture Example M-5

[0663]

[0664]

[0665] Mixture Example M-6

[0666]

[0667] Mixture Example M-7

[0668]

[0669]

[0670] Mixture Example M-8

[0671]

[0672] Mixture Example M-9

[0673] Mixture M-9 consists of 99.935% of mixture M-7, 0.015% of compound ST-12 and 0.05% of compound ST-3b-1

[0674]

[0675] Mixture Example M-10

[0676] Mixture M-10 consists of mixture M-7 containing 250 ppm of compound ST-3a-1

[0677]

[0678] Mixture Example M-11

[0679] Mixture M-11 consists of mixture M-7 containing 500 ppm of compound ST-9-1

[0680]

[0681] Mixture Example M-12

[0682] Mixture Example M-12 contains the following compound CDU-(c3)-F:

[0683]

[0684]

[0685] Mixture Example M-13

[0686] Mixture Example M-13 contains the following compound CDU-(F3)-F:

[0687]

[0688]

[0689]

[0690] Mixture Example M-14

[0691] Mixture M-14 contains the following compound CLY-(c3)2-O2:

[0692]

[0693] Mixture Example M-15

[0694] Mixture M15 contains compound B(S)-2O-O1(c5)

[0695]

[0696] Polymerizable Mixture Examples

[0697] Mixture Example P1

[0698] Mixture Example P1 consists of 99.595% of mixture M-7, 0.40% of compound RM-1 and 0.005% of compound ST-3a-1

[0699]

[0700] Mixture Example P2

[0701] Mixture Example P2 consists of 99.595% of mixture M-1, 0.40% of compound RM-1 and 0.005% of compound ST-3a-1.

[0702] Mixture Example P3

[0703] Mixture Example P3 consists of 99.595% of mixture M-2, 0.40% of compound RM-1 and 0.005% of compound ST-3a-1.

[0704] Mixture Example P4

[0705] Mixture Example P4 consists of 99.595% of mixture M-3, 0.40% of compound RM-1 and 0.005% of compound ST-3a-1.

[0706] Mixture Example P5

[0707] Mixture Example P5 consists of 99.595% of mixture M-4, 0.40% of compound RM-1 and 0.005% of compound ST-3a-1.

[0708] Mixture Example P6

[0709] Mixture Example P6 consists of 99.595% of mixture M-7, 0.40% of compound RM-19 and 0.005% of compound ST-3a-1.

[0710]

[0711] Mixture Example P7

[0712] Mixture Example P7 consists of 99.595% of Mixture M-1, 0.40% of Compound RM-19 and 0.005% of Compound ST-3b-1

[0713]

[0714] Mixture Example P8

[0715] Mixture Example P8 consists of 99.595% of Mixture M-2, 0.40% of Compound RM-35 and 0.005% of Compound ST-3a-1

[0716]

[0717] Mixture Example P9

[0718] Mixture Example P9 consists of 99.595% of Mixture M-7, 0.40% of Compound RM-156 and 0.005% of Compound ST-3a-1

[0719]

[0720] Mixture Example P10

[0721] Mixture Example P10 consists of 99.595% of Mixture M-7, 0.40% of Compound RM-157 and 0.005% of Compound ST-3b-1

[0722]

[0723]

Claims

1. A liquid crystal medium having positive dielectric anisotropy, comprising - one or more compounds of formula I in, R 1 represents H, alkyl or alkoxy having 1 to 12 C atoms, wherein one or more CH2 groups in these groups are optionally replaced by -CH=CH-, -C≡C-, -O-, -CO-O- or -O-CO- is replaced in such a way that the O atoms are not directly connected to each other, and wherein one or more H atoms may be replaced by halogen, and Y 1 Indicates H or CH3; - one or more compounds selected from the group consisting of compounds of formula II-1a, II-1c to II-1h, II-2 and II-3 and compounds of formula III in R 2 and R 3 With formula I for R 1 The meaning given, Independently express L 21 , L 22 , L 23 , L 24 , L 31 and L 32 represent H or F independently of each other, Y 3 Indicates H or CH3, X 2 and X 3 independently of one another represent halogen, haloalkyl or haloalkoxy having 1 to 3 C atoms, or haloalkenyl or haloalkenyloxy having 2 or 3 C atoms, Z 3 represents -CH2CH2-, -CF2CF2-, -COO-, trans-CH=CH-, trans-CF=CF-, -CH2O-, or a single bond, and n and o are independently 0 or 1, wherein the compound of formula I is excluded from the compound of formula III; - and one or more compounds selected from the group consisting of compounds of formula LY-1, LY-2 and LY-3 in R Y1 Alkyl having 1 to 7 C atoms, v is 1, 2, 3, 4, 5, 6 or 7.

2. The liquid crystal medium according to claim 1, wherein the liquid crystal medium further comprises a compound of formula IV-3-2 or IV-3-6 3 . The liquid-crystalline medium according to claim 1 , wherein the liquid-crystalline medium has a clearing temperature of 95° C. or more.

4. The liquid crystal medium according to claim 1 or 2, wherein the liquid crystal medium comprises one or more compounds of formula III selected from the group consisting of compounds of formula III-1 and III-2. where R 3 、X 3 、 L 31 , L 32 , n and o have the meanings defined in claim 1.

5. The liquid crystal medium according to claim 1 or 2, wherein the liquid crystal medium comprises one or more compounds of formula III selected from formulae III-2a to III-2m where R 3 、X 3 , L 31 , L 32 , L 33 and L 34 has the meaning given in claim 1, and L 35 and L 36 represents H or F independently of each other.

6. The liquid-crystalline medium according to claim 1 or 2, wherein the liquid-crystalline medium comprises one or more compounds of the formula V in R 51 、R 52 represents an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, or an alkoxyalkyl group, an alkenyl group or an alkenyloxy group having 2 to 7 carbon atoms, Express the same or differently Z 51 , Z 52 each independently represents -CH2-CH2-, -CH2-O-, -CH=CH-, -C≡C-, -COO- or a single bond, and n is 1 or 2.

7. The liquid-crystalline medium according to claim 1 or 2, wherein the liquid-crystalline medium comprises one or more compounds selected from the group consisting of formulae V-1 to V-17: where R 51 and R 52 represents an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, or an alkoxyalkyl group, an alkenyl group, or an alkenyloxy group having 2 to 7 carbon atoms.

8. The liquid-crystalline medium according to claim 1 or 2, wherein the liquid-crystalline medium comprises one or more polymerizable compounds.

9. A method for producing a liquid crystal medium according to any one of claims 1 to 8, characterized in that One or more compounds of formula I as defined in claim 1 are mixed with one or more compounds of formula II-1a, II-1c to II-1h, II-2, II-3 and / or III and one or more compounds of formula LY-1, LY-2, LY-3. 10 . Use of a liquid-crystalline medium according to claim 1 for electro-optical purposes.

11. The use according to claim 10, wherein the use is for shutter glasses, LC windows, for 3D applications, use in TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, PS-HB-FFS, SA-HB-FFS, polymer-stabilized SA-HB-FFS, positive VA and positive PS-VA displays. 12 . A liquid-crystal display comprising the liquid-crystal medium according to claim 1 .

13. The liquid crystal display of claim 12, wherein the display is a TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, PS-HB-FFS, SA-HB-FFS, polymer-stabilized SA-HB-FFS, positive VA, or positive PS-VA display.

Images