Liquid crystal medium

Abstract

The present invention relates to a liquid crystal (LC) medium or LC material based on a mixture of polar compounds, to the use thereof for optical, electro-optical and electronic purposes, in particular in LC displays, in particular in fringing field switching mode LC displays, to fringing field switching mode LC displays comprising said LC medium, and to the use thereof for optical, electro-optical and electronic purposes, in particular in fringing field switching mode LC displays, in particular in fringing field switching mode LC displays, in particular in fringing field switching mode LC displays, in particular in fringing field switching mode LC displays. The present invention relates to an LC display, in particular an energy-saving LC display, and to a method for manufacturing said LC display.

Description

Technical Field

[0001] The present invention relates to liquid crystal (LC) media or LC materials based on mixtures of polar compounds, to their use for optical, electrooptical and electronic purposes, in particular in LC displays, in particular in LC displays in fringe field switching mode, to LC displays in fringe field switching mode, in particular energy-saving LC displays, comprising such LC media, to methods for preparing such LC media, and to methods for manufacturing such LC displays. Background Art

[0002] One of the currently used liquid crystal display (LCD) modes is the TN ("twisted nematic") mode. However, a disadvantage of TN LCDs is the strong viewing angle dependence of the contrast.

[0003] Thus, so-called FFS ("fringe field switching") displays have been reported (see in particular SH Jung et al., Jpn. J. Appl. Phys., Vol. 43, No. 3, 2004, p. 1028), which contain two electrodes on the same substrate, one of which is structured in a comb-like manner and the other is unstructured. This results in strong so-called "fringe fields", i.e. strong electric fields close to the edges of the electrodes and electric fields with both strong vertical and horizontal components throughout the liquid crystal cell. 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 a planar alignment of the molecules of the LC medium.

[0004] FFS displays can be operated as active matrix or passive matrix displays. In the case of active matrix displays, the individual pixels are typically addressed by integrated non-linear active elements such as transistors (e.g. thin film transistors ("TFT")), while in the case of passive matrix displays, the individual pixels are typically addressed by multiplexing methods, as known from the prior art.

[0005] In addition, a new type of FFS display (called "Ultra Bright FFS (UB-FFS)" mode display) has been disclosed (see SH Lee et al., Appl. Phys. Lett. 73 (20), 1998, pp. 2882-2883, and SH Lee et al., Liquid Crystals 39 (9), 2012, pp. 1141-1148), which has an electrode design and layer thickness similar to that of FFS displays, but contains a layer of LC medium with negative dielectric anisotropy instead of LC medium with positive dielectric anisotropy. The LC medium with negative dielectric anisotropy shows a more favorable director orientation with a smaller tilt and a larger twist orientation than the LC medium with positive dielectric anisotropy, so these displays have higher transmission. The display further comprises an alignment layer provided on at least one of the substrates, preferably an alignment layer of polyimide, which is in contact with the LC medium and induces a planar alignment of the LC molecules of the LC medium. These displays require LC media with high reliability.

[0006] Furthermore, so-called VA ("vertically aligned") displays are known, which have wide viewing angles and fast response times. The LC cell of a VA display contains a layer of LC medium between two transparent electrodes, wherein the LC medium generally has a negative dielectric anisotropy (Δε). In the off state, the molecules of the LC layer are aligned perpendicularly to the electrode surfaces (homeotropically) or have a tilted homeotropic alignment. When a voltage is applied to the two electrodes, a realignment of the LC molecules parallel to the electrode surfaces occurs.

[0007] So-called IPS ("in-plane switching") displays are also known, which contain an LC layer with a planar orientation between two substrates, wherein two electrodes are arranged on only one of the two substrates and preferably have an interdigitated comb structure. When a voltage is applied to the electrodes, an electric field with a significant component parallel to the LC layer is generated between them. This leads to a realignment of the LC molecules in the plane of the layer.

[0008] In the newer types of VA displays, the uniform alignment of the LC molecules is limited to a number of relatively small domains within the LC cell. Disclinations, also called tilted domains, may exist between these domains. VA displays with tilted domains have greater contrast and viewing angle independence of the grey shades relative to conventional VA displays. In addition, this type of display is easier to produce, since additional surface treatment of the electrodes (e.g. by rubbing) is no longer necessary for uniformly aligning the molecules in the switched-on state. Instead, the preferential orientation of the tilt angle or pretilt angle is controlled by a special design of the electrodes.

[0009] However, the use of LC media with negative dielectric anisotropy in VA or FFS displays also has several disadvantages. For example, they have significantly lower reliability compared to LC media with positive dielectric anisotropy.

[0010] The term "reliability" as used hereinafter means the quality of the performance of a display over time and under different stress loads, such as light load, temperature, humidity or voltage, and includes display effects such as image sticking (area and line image sticking), mura, smearing, etc., which are known to those skilled in the art in the field of LC displays. As a standard parameter for classifying reliability, the voltage holding ratio (VHR) value is usually used, which is a measure for maintaining a constant voltage in a test display. The higher the VHR value, the better the reliability of the LC medium.

[0011] The reduced reliability of LC media with negative dielectric anisotropy in VA or FFS displays can be explained by the fact that the LC molecules interact with the polyimide of the alignment layer, so that ions are extracted from the polyimide alignment layer, and that LC molecules with negative dielectric anisotropy do indeed extract such ions more efficiently.

[0012] This leads to new requirements for LC media to be used in VA or FFS displays. In particular, the LC media must show high reliability and high VHR values ​​after UV exposure. Further requirements are high specific resistance, a large operating temperature range, short response times even at low temperatures, low threshold voltage, a wide range of grayscales, high contrast and wide viewing angles, and reduced image sticking.

[0013] Therefore, in displays known from the prior art, undesirable effects so-called "image sticking" or "image burn" are often observed, in which the image produced in the LC display by temporary addressing of individual pixels remains visible even after the electric field in these pixels has been switched off, or after other pixels have been addressed.

[0014] On the one hand, such "image sticking" may occur if LC media with a low VHR are used. The UV component of the backlight or sunlight may cause undesired decomposition reactions of the LC molecules therein and thus initiate the generation of ionic or radical impurities. These may accumulate, especially at the electrodes or alignment layers, where they may reduce the effective applied voltage. Summary of the invention

[0015] It is therefore an object of the present invention to provide improved LC media for use in FFS-, VA- or IPS-displays which do not exhibit the disadvantages described above or exhibit said disadvantages only to a lesser extent and have improved properties. It is a further object of the present invention to provide FFS-, VA- and IPS-displays which have good transmission, high reliability, in particular VHR values ​​after backlight exposure, high specific resistance, a large operating temperature range, short response times even at low temperatures, low threshold voltages, multiple grayscales, high contrast and wide viewing angles, and reduced image sticking.

[0016] Contrast ratio is defined as the ratio of the brightness of the brightest shade (white) to the brightness of the darkest shade (black) that the system can produce, that is, the ratio of transmittance (white level) to the scattering parameter (dark level). The contrast ratio can be increased by lower scattering parameters (high K 平均 and low △ n) are significantly improved. Therefore, with high K 平均 LC mixtures with low Δn are very effective for realizing high contrast displays. Another object of the present invention is to provide LC mixtures with advantageously high average elastic constants K 平均 and low birefringence △n, while maintaining low rotational viscosity γ 1 LC mixture.

[0017] It has been found that one or more of these objects can be achieved by providing an LC medium as disclosed and claimed hereinafter.

[0018] The present invention therefore relates to a liquid-crystalline medium comprising one or more compounds of the formula I

[0019]

[0020] and

[0021] One or more compounds of formula III

[0022]

[0023] and / or

[0024] One or more compounds of formula BC

[0025]

[0026] and / or

[0027] One or more compounds of formula PH-1

[0028]

[0029] in

[0030] R 11 , R 31 , R 32 , R 81 , and R 82 each independently of one another represents H, an alkyl or alkoxy radical having 1 to 15 C atoms, preferably having 1 to 7 C atoms, wherein one or more of these radicals -CH 2 - groups can each be independently -C≡C-, -CF 2 O-, -OCF 2 -, -CH=CH-, is replaced by -O-, -CO-O- or -O-CO- in such a way that the O atoms are not directly attached to one another, and wherein one or more H atoms may be replaced by halogen, R 12 denotes an alkenyl group having 2 to 12 C atoms, preferably 2 to 7 C atoms,

[0031] A 3 In each case, independently of one another, denotes a 1,4-phenylene radical in which one or two CH groups may be replaced by N, or a 1,4-cyclohexylene or a 1,4-cyclohexenylene radical in which one or two non-adjacent CH 2 The group may be substituted by -O- or -S-, wherein the group may be mono- or poly-substituted by halogen atoms,

[0032] n represents 0, 1 or 2,

[0033] Z 3 In each occurrence, it is expressed independently from each other -CF 2 O-, -OCF 2 -,-CH 2 O-, -OCH 2 -,-CH 2 -,-CH 2 CH 2 -, -CH=CH-, -C≡C- or single bond,

[0034] L 31 and L 32 , each independently of the other, represents F, Cl, CF 3 or CHF 2,and

[0035] Y 1 , Y 2 , Y 3 , and Y 4 , each independently represents H, F, Cl, CF 3 , CHF 2 , CH 3 or OCH 3 , preferably H, CH 3 or OCH 3 , H is very preferred.

[0036] The invention also relates to an LC display comprising a liquid-crystalline medium as described above and as described below, in particular VA, IPS, FFS, PS-VA, PS-IPS, PS-FFS, UB-FFS or UV 2 A display.

[0037] The invention also relates to a liquid-crystalline medium as described above and below in VA, IPS, FFS, PS-VA, PS-IPS, PS-FFSUB-FFS or UV 2 A Use in display.

[0038] The invention furthermore relates to a process for preparing an LC medium as described above and below, which process comprises the step of mixing one or more compounds of the formula I with one or more compounds of the formula III and optionally with further LC compounds and / or additives.

[0039] The invention furthermore relates to a method of manufacturing an LC display as described above and below, comprising the step of filling or otherwise providing an LC medium as described above and below between the substrates of said display.

[0040] The LC media according to the invention allow one or more of the following advantageous effects to be achieved:

[0041] - Advantageously high average elastic constant K 平均 , which is equal to (K 1 +K 2 +K 3 ) / 3, which contributes to low scattering parameters,

[0042] - Low birefringence combined with a high average elastic constant contributes to high contrast,

[0043] -Low viscosity enabling fast response time,

[0044] - low threshold voltage, which can be used to reduce driving voltage and enable energy-saving displays,

[0045] - Enables a production process for LC panels that is time- and cost-effective and energy-efficient.

[0046] The LC media according to the invention, when used in LC displays, exhibit one or more of the following advantageous properties:

[0047] - High contrast,

[0048] - High transmittance,

[0049] — reduced rotational viscosity,

[0050] —Fast response time,

[0051] - Low threshold voltage, which can be used to realize energy-saving displays.

[0052] Above and below, represents a trans-1,4-cyclohexylene ring,

[0053] and It represents a 1,4-phenylene ring.

[0054] In the group In the present invention, a single bond shown between two ring atoms may be attached to any free position of the benzene ring.

[0055] If in the formulae shown above and below, such as R 11,12 , R 21,22 , R 31,32,33 , R 41,42 , R 51,52 , R 61 , R 71 , R N1 ,N2 , R 81,82 , R 91,92,93 , R L1,L2 , R Q , R R1,R2 If the terminal group of L represents an alkyl group and / or an alkoxy group, it may be straight-chain or branched. It is preferably straight-chain, has 2, 3, 4, 5, 6 or 7 C atoms, and therefore preferably represents ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy or heptyloxy, and also methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy or tetradecyloxy.

[0056] If one of the above-mentioned terminal groups represents one or more CH 2If the alkyl radical is replaced by S, it may be straight-chain or branched. It is preferably straight-chain, has 1, 2, 3, 4, 5, 6 or 7 C atoms and therefore preferably represents thiomethyl, thioethyl, thiopropyl, thiobutyl, thiopentyl, thiohexyl or thioheptyl.

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

[0058] If one of the abovementioned terminal groups represents an alkoxy or oxaalkyl group, it may also contain one or more additional oxygen atoms, provided that the oxygen atoms are not directly bonded to one another.

[0059] If one of the terminal groups mentioned above represents one of the CH 2 The alkyl radical which 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- or -2-enyl, but-1-, -2- or -3-enyl, pent-1-, -2-, -3- or -4-enyl, hex-1-, -2-, -3-, -4- or -5-enyl, hept-1-, -2-, -3-, -4-, -5- or -6-enyl, oct-1-, -2-, -3-, -4-, -5-, -6- or -7-enyl, non-1-, -2-, -3-, -4-, -5-, -6-, -7- or -8-enyl, dec-1-, -2-, -3-, -4-, -5-, -6-, -7-, -8- or -9-enyl.

[0060] If one of the abovementioned terminal groups represents an alkyl or alkenyl group which is at least monosubstituted by halogen, this group is preferably straight-chain and the halogen is preferably F or Cl. In the case of polysubstitution, the halogen is preferably F. The resulting groups also include perfluorinated groups. In the case of monosubstitution, the fluorine or chlorine substituent can be in any desired position, but is preferably in the ω-position.

[0061] In another preferred embodiment, one or more of the above-mentioned terminal groups, such as R 11,12 , R 21 ,22 , R 31,32,33 , R 41,42 , R 51,52, R 61 , R 71 , R N1,N2 , R 81,82 , R 91,92,93 , R L1,L2 , R Q , R R1,R2 or L, selected from

[0062]

[0063] -S 1 -F, -OS 1 -F, -OS 1 -OS 2 , where S 1 It is C 1-12 Alkylene or C 2-12 Alkenylene, and S 2 It is H, C 1-12 Alkyl or C 2-12 Alkenyl, and very preferably selected from

[0064]

[0065] -O(CH 2 ) 2 OCH 3 ,-O(CH 2 ) 3 OCH 3 ,-O(CH 2 ) 4 OCH 3 ,-O(CH 2 ) 2 F,-O(CH 2 ) 3 F,-O(CH 2 ) 4 F.

[0066] Halogen is preferably F or Cl, very preferably F.

[0067] Group-CR 0 =CR 00 - is preferably -CH=CH-.

[0068] -CO-, -C(=O)- and -C(O)- represent carbonyl groups, i.e.

[0069] Preferred substituents L are, for example, F, Cl, Br, I, -CN, -NO 2 , -NCO, -NCS, -OCN, -SCN, -C(=O)N(R x ) 2 、-C(=O)Y1 、-C(=O)R x 、-N(R x ) 2 , linear or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, each having 1 to 25 C atoms, wherein 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,

[0070] Where R x represents H, F, Cl, CN or a linear, branched or cyclic alkyl radical having 1 to 25 C atoms, wherein one or more non-adjacent CH 2 The group is optionally 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 attached to one another, and wherein one or more H atoms are each optionally replaced by F, Cl, P- or P-Sp-, and

[0071] Y 1 Represents halogen.

[0072] Particularly preferred substituents L are, for example, F, Cl, CN, NO 2 , CH 3 , C 2 H 5 、OCH 3 , OC 2 H 5 、COCH 3 、COC 2 H 5 、COOCH 3 、COOC 2 H 5 CF 3 、OCF 3 , OCHF 2 , OC 2 F 5 , and phenyl.

[0073] Preferably wherein L has one of the meanings indicated above.

[0074] In a preferred embodiment, the LC media according to the invention comprise one or more compounds of the formula I in which R 11 and R 12 Independently of one another represent straight-chain alkyl having 1 to 7 C atoms or alkenyl having 2 to 7 C atoms.

[0075] In a preferred embodiment, the LC media according to the invention comprise one or more compounds of the formula I, preferably selected from the group consisting of the compounds of the formulae Ia to Ie:

[0076]

[0077]

[0078] wherein alkyl and alkyl* each independently represent an alkyl group having 1 to 7 C atoms, alkenyl and alkenyl* each independently represent an alkenyl group having 2 to 7 C atoms, and cycloalkyl represents a cyclic alkyl group having 3 to 12 C atoms, preferably cyclopropyl, cyclobutyl, cyclopentyl, cyclopropylalkyl, cyclobutylalkyl or cyclopentylalkyl.

[0079] Very preferred compounds of the formulae Ia to Ie are selected from the compounds of the formulae Ib-1 to Ib-3, Ic-1 to Ic-4, Id-1 to Id-7 and Ie-1 to Ie-8.

[0080]

[0081]

[0082]

[0083] wherein alkyl represents ethyl, n-propyl, n-butyl or n-pentyl, preferably n-propyl.

[0084] The preferred compound of formula I is Ib-1, and the most preferred is compound CCC-3-V.

[0085] Preferred compounds of formula III are those of formula III-1 to III-6:

[0086]

[0087] The radicals occurring therein have the same meanings as given above under formula III and are preferably

[0088] R 31 and R 32 each independently of one another represents an alkyl, alkenyl or alkoxy group having up to 15 C atoms, preferably having 1 to 7 C atoms, more preferably one or both of them represent an alkoxy group; or a cyclic alkyl group having 3 to 6 C atoms,

[0089] R 33 represents an alkyl or alkenyl group having up to 7 C atoms, or a group Cy-C n H 2n+1 -,

[0090] m and n, identically or differently, are 0, 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, very preferably 1,

[0091] Cy denotes an alicyclic 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, cyclopentyl or cyclopentenyl,

[0092] (O) represents O or a single bond,

[0093] L 31 and L 32 Each independently represents F or Cl, preferably both represent F, and

[0094] Y 3 Indicates H, F, Cl, CF 3 , CHF 2 , CH 3 or OCH 3 , preferably H or CH 3 .

[0095] In another preferred embodiment, the LC medium comprises one or more compounds of the formula III-1 selected from the group consisting of the formulae III-1-1 to III-1-20, preferably the formulae III-1-1 and III-1-11,

[0096]

[0097]

[0098]

[0099] wherein 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 31 and L 32 Each independently represents F or Cl, preferably both represent F.

[0100] Very preferred compounds of formula III-1-1 are selected from the following sub-formulae,

[0101]

[0102] Very preferred compounds of formula III-1-11 are selected from the following sub-formulae,

[0103]

[0104]

[0105] A very preferred compound of formula III-2 is as follows,

[0106]

[0107]

[0108] Here, alkoxy denotes straight-chain alkoxy having 1 to 6 C atoms, preferably ethoxy, propoxy, butoxy or pentoxy, very preferably ethoxy or propoxy, and alkenyl denotes straight-chain alkenyl having 2 to 6 C atoms.

[0109] Very preferred compounds of formula III-6 are selected from the following formula,

[0110]

[0111]

[0112]

[0113] Where R 32 represents an alkyl group having 1 to 7 C atoms, preferably ethyl, n-propyl or n-butyl, or cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl, or -(CH 2 ) n F, wherein n is 2, 3, 4 or 5, preferably C 2 H 4 F.

[0114] Preferred compounds of formula III are III-1-1-3, III-1-1-4, III-1-1-5, III-2-7, and III-6-2, and the most preferred are compounds B(S)-2O-O4, B(S)-2O-O5, B(S)-2O-O6, B(S)-1V1O-O1(c5), and COB(S)-2-O4.

[0115] Further preferred embodiments of the LC media according to the invention are listed below, including any combinations thereof.

[0116] Preferably, the LC medium further comprises one or more compounds of formula II,

[0117]

[0118] where the individual radicals, independently of one another and identically or differently on each occurrence, have the following meanings:

[0119] R 21 and R 22 represents a straight-chain, branched or cyclic alkyl or alkoxy group having 1 to 20 C atoms, wherein one or more non-adjacent CH 2 The group is optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, CR 0 =CR 00 -,-C≡C-,

[0120]

[0121] In such a way that the O and / or S atoms are not directly connected to each other, and one or more H atoms are each optionally replaced by F, Cl, CN or CF 3 Alternatively, preferably alkyl or alkoxy having 1 to 6 C atoms,

[0122] R 0 , R 00 represents H or an alkyl group having 1 to 12 C atoms,

[0123] A 1 and A 2 represents a group selected from the following formula

[0124]

[0125] Preferably selected from the formulae A1, A2, A3, A4, A5, A6, A9 and A10, very preferably selected from the formulae A1, A2, A3, A4, A5, A9 and A10,

[0126] Z 1 and Z 2 -CH 2 CH 2 -, -CH=CH-, -CF 2 O-, -OCF 2 -,-CH 2 O-, -OCH 2 -, -CO-O-, -O-CO-, -C 2 F 4 -, -CF=CF-, -CH=CH-CH 2 O- or a single bond, preferably a single bond,

[0127] L 1 , L 2 , L 3 and L 4 F, Cl, OCF 3 , C.F. 3 , CH 3 , CH 2F or CHF 2 , preferably F or Cl, very preferably F,

[0128] Y is H, F, Cl, CF 3 , CHF 2 or CH 3 , preferably H or CH 3 , H is highly preferred,

[0129] L C CH 3 or OCH 3 , preferably CH 3 ,

[0130] a1 is 0, 1 or 2,

[0131] a2 is 0 or 1.

[0132] Preferably, the LC medium comprises one or more compounds of formula II selected from the group consisting of compounds of formulae IIA, IIB, IIC, IID, IIE, and IIF,

[0133]

[0134] where the individual radicals, identically or differently on each occurrence and independently of one another, have the following meanings:

[0135] R 21 , R 22 represents H, an alkyl, alkoxy or alkenyl group having up to 15 C atoms, which is unsubstituted or replaced by F, Cl, CN or CF 3 monosubstituted, and wherein one or more CH 2 The group can also be -O-, -S-, -C≡C-, -CF 2 O-, -OCF 2 -, -OC-O-, -O-CO-

[0136]

[0137] Replace in such a way that O and / or S atoms are not directly connected to each other,

[0138] L 1 To L 4 Indicates F, Cl, CF 3 or CHF 2 ,

[0139] Y represents H, F, Cl, CF 3 , CHF 2 or CH 3 , preferably H or CH 3, particularly preferably H,

[0140] Z 1 , Z 2 Represents a single bond, -CH 2 CH 2 -、-CH=CH-、-CF 2 O-、-OCF 2 -、-CH 2 O-、-OCH 2 -、-COO-、-OCO-、-C 2 F 4 -, -CF=CF-, -CH=CHCH 2 O-,

[0141] p represents 0, 1, or 2, and

[0142] q represents 0 or 1.

[0143] Preferred compounds of formula IIA, IIB, IIC, IID and IIE are those wherein R 22 represents an alkyl or alkoxy group having up to 15 C atoms and very preferably represents (O)C v H 2v+1 Those compounds wherein (O) is an oxygen atom or a single bond, and v is 1, 2, 3, 4, 5 or 6.

[0144] Further preferred compounds of formula IIA, IIB, IIC, IID and IIE are those wherein R 21 or R 22 Those compounds which represent or contain a cycloalkyl or cycloalkoxy group, the cycloalkyl or cycloalkoxy group being preferably selected from:

[0145]

[0146] Where S 1 It is C 1-12 Alkylene or C 2-12 Alkenylene, and S 2 It is H, C 1-12 Alkyl or C 2-12 Alkenyl, and very preferably selected from:

[0147]

[0148]

[0149] Additional preferred compounds of the formulae IIA, IIB, IIC, IID and IIE are indicated below.

[0150] In a preferred embodiment, the LC medium comprises one or more compounds of formula IIIA selected from the following formulae:

[0151]

[0152]

[0153]

[0154]

[0155]

[0156]

[0157]

[0158]

[0159]

[0160]

[0161]

[0162] wherein the index a denotes 1 or 2, alkyl and alkyl* each independently denote a straight-chain or branched alkyl radical having 1 to 6 C atoms, alkeneyl denotes a straight-chain or branched alkenyl radical having 2 to 6 C atoms, and (O) denotes an oxygen atom or a single bond, and alkeneyl preferably denotes CH 2 =CH-, CH 2 =CHCH 2 CH 2 -, CH 3 -CH=CH-, CH 3 -CH 2 -CH=CH-,CH 3 -(CH 2 ) 2 -CH=CH-,CH 3 -(CH 2 ) 3 -CH=CH- or CH 3 -CH=CH-(CH 2 ) 2 -.

[0163] Particularly preferred LC media according to the invention comprise one or more compounds selected from the group consisting of formulae IIA-2, IIA-8, IIA-10, IIA-16, IIA-18, IIA-40, IIA-41, IIA-42, IIA-43, IIA-67, IIA-69, and IIA-81.

[0164] Preferably, the LC medium comprises one or more compounds of formula IIA-2 selected from the following subformulae:

[0165]

[0166]

[0167] Alternatively, preferably, the LC medium comprises, in addition to the compounds of the formulae IIA-2-1 to IIA-2-5, one or more compounds of the following formulae:

[0168]

[0169] Further preferably, the LC medium comprises one or more compounds of formula IIA-10 selected from the following subformulae:

[0170]

[0171] Alternatively, preferably, the LC medium comprises, in addition to the compounds of the formulae IIA-10-1 to IIA-10-6, one or more compounds of the following formulae:

[0172]

[0173]

[0174] Further preferably, the LC medium comprises one or more compounds of formula IIA-16 selected from the following subformulae:

[0175]

[0176] Further preferably, the LC medium comprises one or more compounds of formula IIA-40 selected from the following subformulae:

[0177]

[0178] Alternatively, preferably, the LC medium comprises, in addition to the compounds of the formulae IIA-40-1 to IIA-40-5, one or more compounds of the following formulae:

[0179]

[0180]

[0181] Further preferably, the LC medium comprises one or more compounds of formula IIA-42 selected from the following subformulae:

[0182]

[0183]

[0184] Further preferably, the LC medium comprises one or more compounds of formula IIA-67 selected from the following subformulae:

[0185]

[0186] Further preferably, the LC medium comprises one or more compounds of formula IIA-69 selected from the following subformulae:

[0187]

[0188]

[0189] Further preferably, the LC medium comprises one or more compounds of formula IIA-81 selected from the following subformulae:

[0190]

[0191]

[0192] Preferred LC media additionally comprise one or more compounds of the formula IIA-Y,

[0193]

[0194] Where R 21 and R 22 has one of the meanings given above in Formula IIIA, and L 1 and L 2 , identically or differently, represents F or Cl.

[0195] Preferred compounds of formula IIA-Y are selected from the following sub-formulae:

[0196]

[0197]

[0198] wherein Alkyl and Alkyl* each independently represent a straight-chain or branched alkyl group having 1 to 6 C atoms, Alkoxy represents a straight-chain or branched alkoxy group having 1 to 6 C atoms, Alkenyl and Alkenyl* each independently represent a straight-chain or branched alkenyl group having 2 to 6 C atoms, and O represents an oxygen atom or a single bond. Alkenyl and Alkenyl* preferably represent CH 2 =CH-, CH 2 =CHCH 2 CH 2 -, CH 3 -CH=CH-, CH 3 -CH 2 -CH=CH-, CH 3 -(CH 2 ) 2 -CH=CH-, CH 3 -(CH 2 ) 3 -CH=CH- or CH 3 -CH=CH-(CH 2 ) 2 -.

[0199] Particularly preferred compounds of formula IIA-Y are selected from the following sub-formulae:

[0200]

[0201] Therein Alkoxy and Alkoxy* have the meanings defined above and preferably denote methoxy, ethoxy, n-propoxy, n-butoxy or n-pentoxy.

[0202] In another preferred embodiment, the LC medium comprises one or more compounds of the formula II B selected from the group consisting of formulae II B-1 to II B-26,

[0203]

[0204]

[0205]

[0206]

[0207]

[0208] wherein alkyl and alkyl* each independently represent a straight-chain or branched alkyl radical having 1 to 6 C atoms, alkenyl represents a straight-chain or branched alkenyl radical having 2 to 6 C atoms, and (O) represents an oxygen atom or a single bond, and alkenyl preferably represents CH 2 =CH-, CH 2 =CHCH 2 CH 2 -, CH 3 -CH=CH-, CH 3 -CH 2 -CH=CH-, CH 3 -(CH 2 ) 2 -CH=CH-, CH 3 -(CH 2 ) 3 -CH=CH- or CH 3 -CH=CH-(CH 2 ) 2 -.

[0209] Particularly preferred LC media according to the invention comprise one or more compounds selected from the group consisting of formulae IIB-2, IIB-11 and IIB-17.

[0210] Preferably, the LC medium comprises one or more compounds of formula II B-11 selected from the following subformulae:

[0211]

[0212] Alternatively, preferably, the LC medium comprises, in addition to the compounds of the formulae IIB-11-1 to IIB-11-5, one or more compounds of the formulae IIB-11a-1 to IIB-11a-5:

[0213]

[0214] Preferably, the LC medium comprises one or more compounds of formula II B-17 selected from the following subformulae:

[0215]

[0216]

[0217] In another preferred embodiment, the LC medium comprises one or more compounds of formula IIC selected from formula IIC-1,

[0218]

[0219] wherein alkyl and alkyl* each independently of one another denote a straight-chain alkyl group having 1 to 6 C atoms, preferably in an amount of 0.5 to 5% by weight, in particular 1 to 3% by weight.

[0220] In another preferred embodiment, the LC medium comprises one or more compounds of formula IID selected from the following formulae,

[0221]

[0222]

[0223]

[0224]

[0225] wherein alkyl and a lkyl* each independently represent a straight-chain or branched alkyl radical having 1 to 6 C atoms, alkenyl represents a straight-chain or branched alkenyl radical having 2 to 6 C atoms, and (O) represents an oxygen atom or a single bond, and a lkenyl preferably represents CH 2 =CH-, CH 2 =CHCH 2 CH 2 -, CH 3 -CH=CH-, CH 3 -CH 2 -CH=CH-, CH 3 -(CH 2 ) 2 -CH=CH-, CH 3 -(CH 2 ) 3 -CH=CH- or CH 3 -CH=CH-(CH 2 ) 2 -.

[0226] Particularly preferred LC media according to the invention comprise one or more compounds of the formulae I ID-1, I ID-4, I ID-12 and / or I ID-19.

[0227] Very preferred compounds of formula I ID are selected from the following subformulae of I ID-1,

[0228]

[0229]

[0230]

[0231]

[0232] where v is 1, 2, 3, 4, 5, or 6.

[0233] Very preferred compounds of formula I ID are selected from the following subformulae of I ID-4,

[0234]

[0235]

[0236]

[0237]

[0238] where v is 1, 2, 3, 4, 5, or 6.

[0239] Very preferred compounds of formula I ID are selected from the following sub-formulas of I ID-12,

[0240]

[0241]

[0242]

[0243] Where v is 1, 2, 3, 4, 5 or 6.

[0244] In a preferred embodiment, the LC medium comprises one or more compounds of formula IID-12a,

[0245]

[0246] Where R 21 , Y and q have the meanings given in Formula I ID, and R 23 for

[0247] where r is 0, 1, 2, 3, 4, 5 or 6 and s

[0248] 1, 2 or 3.

[0249] Preferred compounds of formula IID-10a are compounds IID-12a-1 to IID-12a-14:

[0250]

[0251]

[0252]

[0253] Very preferred compounds of formula I ID are selected from the following subformulas of I ID-19,

[0254]

[0255]

[0256]

[0257]

[0258]

[0259] where v is 1, 2, 3, 4, 5, or 6.

[0260] In a preferred embodiment, the LC medium comprises one or more compounds of formula IIE selected from the following formulae:

[0261]

[0262]

[0263]

[0264]

[0265]

[0266]

[0267]

[0268]

[0269]

[0270]

[0271]

[0272] wherein the index a denotes 1 or 2, alkyl and alkyl* each independently denote a straight-chain alkyl radical having 1 to 6 C atoms, alkenyl denotes a straight-chain alkenyl radical having 2 to 6 C atoms, and (O) denotes an oxygen atom or a single bond, and alkenyl preferably denotes CH 2 =CH-, CH 2 =CHCH 2 CH 2 -、CH 3 -CH=CH-, CH 3 -CH2 -CH=CH-, CH 3 -(CH 2 ) 2 -CH=CH-, CH 3 -(CH 2 ) 3 -CH=CH- or CH 3 -CH=CH-(CH 2 ) 2 -.

[0273] Particularly preferred LC media according to the invention comprise one or more compounds selected from the group consisting of formulae I IE-2, I IE-8, I IE-10, I IE-16, I IE-18, I IE-37, I IE-38, I IE-39 and I IE-40.

[0274] Preferably, the LC medium comprises one or more compounds of formula IIE-2 selected from the following subformulae:

[0275]

[0276]

[0277] Preferably, the LC medium comprises one or more compounds of formula IIE-10 selected from the following subformulae:

[0278]

[0279] In another preferred embodiment, the LC medium comprises one or more compounds of formula IIF selected from the group consisting of

[0280]

[0281]

[0282] wherein alkyl and alkyl* each independently represent a straight-chain or branched alkyl radical having 1 to 6 C atoms.

[0283] Preferably, the LC medium comprises one or more compounds of formula IIF-2 selected from the following subformulae:

[0284]

[0285] Particularly preferred LC media according to the invention comprise one or more compounds selected from the group consisting of formula IIA-2, IIA-8, IIA-10, IIA-16, IIA-18, IIA-40, IIA-41, IIA-42, IIA-43, IIA-67, IIA-69, IIA-81, IIB-2, IIB-10, IIB-16, IIC-1, and IID-1, IID-4, IID-12, IID-19, IIE-2, IIE-8, IIE-10, IIE-16, IIE-18, IIE-37, IIE-38, IIE-39, IIE-40, and IIF-2 or subformulae thereof.

[0286] The proportion of compounds of the formula IIA and / or IIB in the mixture as a whole is preferably at least 20% by weight.

[0287] Preferably, the LC medium further comprises one or more compounds of formula IIIA:

[0288]

[0289] Where R 31 , R 32 , A 3 , Z 3 , L 31 , L 32 , Y 1 , Y 2 , Y 3 , Y 4 , and n have the meanings given above in formula III.

[0290] In a preferred embodiment of the present invention, the LC medium comprises one or more compounds of the formula IIIA-1:

[0291]

[0292] The radicals occurring therein have the same meanings as given above under formula IIIA and are preferably

[0293] R 31 and R 32 each independently of one another, an alkyl, alkenyl or alkoxy group having up to 15 C atoms, preferably having 1 to 7 C atoms, more preferably one or both of them represent an alkoxy group, or a cyclic alkyl group having 3 to 6 C atoms, and

[0294] L 31 and L 32 Each independently of one another represents F or Cl, preferably both represent F.

[0295] In another preferred embodiment, the LC medium comprises one or more compounds of the formula IIIA-1 selected from the group consisting of the formulae IIIA-1-1 to IIIA-1-20, preferably the formulae IIIA-1-8 and IIIA-1-18,

[0296]

[0297]

[0298]

[0299]

[0300] wherein alkyl and alkyl* each independently represent a straight-chain alkyl group having 1 to 6 C atoms, or, or a cyclic alkyl group having 3 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 31 and L 32 Each independently represents F or Cl, preferably both represent F.

[0301] Preferably, the LC medium comprises one or more compounds of formula IIIA-1-8 selected from the following subformulae:

[0302]

[0303] Preferably, the LC medium comprises one or more compounds of formula IIIA-1-18 selected from the following subformulae:

[0304]

[0305] In another preferred embodiment of the present invention, the LC medium comprises one or more compounds of the formula IIIA-2

[0306]

[0307] Where L 31 and L 32 has the same meaning as given under formula IIIA, (O) represents O or a single bond,

[0308] R 33 represents an alkyl or alkenyl group having up to 7 C atoms, or a group Cy-C n H 2n+1 -,

[0309] m and n, identically or differently, are 0, 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, very preferably 1, and

[0310] Cy denotes an alicyclic radical having 3, 4 or 5 ring atoms, which is optionally substituted by alkyl or alkenyl having up to 3 C atoms each, or by halogen or CN, and preferably denotes cyclopropyl, cyclobutyl, cyclopentyl or cyclopentenyl,

[0311] The compound of formula IIIA-2 is contained in the LC medium either instead of or in addition to the compound of formula III, preferably in addition.

[0312] A highly preferred compound of formula IIIA-2 is as follows,

[0313]

[0314]

[0315] Here, alkoxy represents a straight-chain alkoxy group having 1 to 6 C atoms.

[0316] In another preferred embodiment, the LC medium comprises one or more compounds of the formula IIIA selected from compounds of the formulae IIIA-3 to IIIA-5,

[0317]

[0318] The radicals occurring therein have the same meanings as given under formula III, and R 31 Preferably, it represents a linear alkyl group or a cyclic alkyl group and R 32 Preference is given to alkoxy radicals which in each case have 1 to 7 C atoms.

[0319] In a preferred embodiment of the present invention, the LC medium comprises one or more compounds of the formula IIIA-6:

[0320]

[0321] The radicals occurring therein have the same meanings and preferences as given under formula III

[0322] R 31 and R 32 Each independently of one another is an alkyl, alkenyl or alkoxy group having up to 15 C atoms, preferably having 1 to 7 C atoms, more preferably one or both of them represent an alkoxy group.

[0323] Very preferred compounds of formula IIIA-6 are selected from the following formula,

[0324]

[0325]

[0326] Where R 32 represents an alkyl group having 1 to 7 C atoms, preferably ethyl, n-propyl or n-butyl, or cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl, or -(CH 2 ) n F, wherein n is 2, 3, 4 or 5, preferably C 2 H 4 F.

[0327] In a preferred embodiment of the present invention, the LC medium comprises at least one compound of the formula I, at least one compound of the formula III and at least one compound of the formula IIIA.

[0328] In a preferred embodiment, the LC medium comprises one or more compounds of formula IV,

[0329]

[0330] in

[0331] R 41 represents an unsubstituted alkyl group having 1 to 7 C atoms, wherein one or more CH 2 The group can also be

[0332]

[0333] or an unsubstituted alkenyl radical having 2 to 7 C atoms, preferably an n-alkyl radical, which particularly preferably has 2, 3, 4 or 5 C atoms, and

[0334] R 42 represents an unsubstituted alkyl group having 1 to 7 C atoms, or a cyclic alkyl group having 3 to 6 C atoms or an unsubstituted alkoxy group having 1 to 6 C atoms, both preferably having 2 to 5 C atoms, an unsubstituted alkenyl group having 2 to 7 C atoms, preferably having 2, 3 or 4 C atoms, more preferably a vinyl group or a 1-propenyl group, and in particular a vinyl group.

[0335] The compound of formula IV is preferably selected from the compounds of formulae IV-1 to IV-4,

[0336]

[0337] in

[0338] alkyl and alkyl* independently of one another denote an alkyl group having 1 to 7 C atoms, preferably having 2 to 5 C atoms,

[0339] Alkenyl is an alkenyl radical having 2 to 5 C atoms, preferably having 2 to 4 C atoms, particularly preferably 2 C atoms,

[0340] a lkenyl* denotes an alkenyl group having 2 to 5 C atoms, preferably having 2 to 4 C atoms, particularly preferably having 2 to 3 C atoms, and

[0341] Alkoxy is an alkoxy group having 1 to 5 C atoms, preferably having 2 to 4 C atoms.

[0342] Preferably, the LC medium comprises one or more of the following compounds selected from the compounds of formulae IV-1-1 to IV-1-14:

[0343]

[0344]

[0345]

[0346] wherein alkyl represents methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or n-pentyl.

[0347] Very preferably, the LC media according to the invention comprise one or more compounds of the formula IV-2-1 and / or IV-2-2

[0348]

[0349] Very preferably, the LC media according to the invention comprise a compound of the formula IV-3, in particular a compound selected from the group consisting of the formulae IV-3-1 to IV-3-9:

[0350]

[0351]

[0352] The LC media according to the invention preferably comprise one or more compounds CC-nV and / or CC-n-Vm, in particular CC-3-V, CC-4-V, CC-3-V1 and / or CC-4-V1, preferably in a total concentration in the range from 15 to 70%, preferably from 25 to 55%, very preferably from 30 to 50%. CC-3-V is preferably used in a concentration of 5 to 60%, in particular 10 to 55%.

[0353] In another preferred embodiment, the LC media according to the invention comprise one or more compounds of the formula IV-3 selected from the compounds of the formulae IV-3-10 to IV-3-25:

[0354]

[0355]

[0356]

[0357] Very preferably, the LC media according to the invention comprise compounds of the formula IV-4, which are in particular selected from the compounds of the following formulae:

[0358]

[0359] In another preferred embodiment, the LC medium comprises one or more compounds of formula IV-4 and its subformulae, wherein one or both of "alkenyl" and "alkenyl'" represent Wherein m is 0, 1 or 2, and n is 0, 1 or 2, very preferred are compounds selected from the group consisting of formulae IV-4-3 to IV-4-6.

[0360] Very preferably, the LC medium according to the invention comprises one or more compounds of the formula IV-1 or its subformulae and / or one or more compounds of the formula IV-3 or its subformulae and / or one or more compounds of the formula IV-4 or its subformulae, wherein the total concentration of these compounds of the formula IV-1 is in the range from 1% to 30%.

[0361] The LC media according to the invention preferably additionally comprise one or more compounds of the formula IVa,

[0362]

[0363] in

[0364] R 41 and R 42 each independently of one another represents a straight-chain alkyl, alkoxy, alkenyl, alkoxyalkyl or alkoxy group having up to 12 C atoms, or a cyclic alkyl group having 3 to 6 C atoms,

[0365] express

[0366]

[0367] Z 4 Represents a single bond, -CH 2 CH 2 -、-CH=CH-、-CF 2 O-、-OCF 2 -、-CH 2 O-、-OCH 2 -、-COO-、-OCO-、-C 2 F4 -、-C 4 H 8 -or-CF=CF-.

[0368] Preferred compounds of formula IVa are indicated below:

[0369]

[0370]

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

[0372] The LC media according to the invention preferably comprise at least one compound of the formula IVa-1 and / or formula IVa-2.

[0373] The proportion of the compound of the formula IVa in the mixture as a whole is preferably at least 5% by weight.

[0374] Preferably, the LC medium comprises one or more compounds of the formulae IVb-1 to IVb-3,

[0375]

[0376] in

[0377] a lkyl and alkyl* each independently represent a straight-chain alkyl group having 1 to 6 C atoms, or a cyclic alkyl group having 3 to 6 C atoms, preferably a lkyl represents a methyl group, and

[0378] Alkenyl and alkenyl* each independently of one another represent a straight-chain alkenyl radical having 2 to 6 C atoms.

[0379] The proportion of compounds of the formulae IV-1 to IV-3 in the mixture as a whole is preferably at least 3% by weight, in particular ≥5% by weight.

[0380] Among the compounds of the formulae IVa-1 to IVa-4, the compound of the formula IVa-2 is particularly preferred.

[0381] Among the compounds of the formulae IVb-1 to IVb-3, the compounds of the formula IVb-2 are particularly preferred.

[0382] Particularly preferred compounds of formula IV-1 to IV-3 are selected from the following formulae,

[0383]

[0384] Here, alkyl* denotes an alkyl group having 1 to 6 C atoms and preferably denotes n-propyl.

[0385] The LC media according to the invention particularly preferably comprise one or more compounds of the formula IVb-1-1, IVb-2-3 and / or IVb-2-4.

[0386] In another preferred embodiment, the LC media according to the invention comprise one or more compounds of the formula V,

[0387]

[0388] in

[0389] R 51 and R 52 independently of one another represents H, an alkyl, alkoxy or alkenyl group having up to 15 C atoms, which is unsubstituted, replaced by F, Cl, CN or CF 3 monosubstituted or at least monosubstituted by halogen, wherein one or more CH 2 The group can also be -O-, -S-, -C≡C-, -CF 2 O-, -OCF 2 -, -OC-O-, -O-CO-

[0390]

[0391] is replaced in such a way that the O atoms are not directly attached to one another and preferably represents alkyl having 1 to 7 C atoms, preferably n-alkyl, particularly preferably n-alkyl having 1 to 5 C atoms, alkoxy having 1 to 6 C atoms, preferably n-alkoxy, particularly preferably n-alkoxy having 2 to 5 C atoms, alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7 C atoms, preferably 2 to 4 C atoms, preferably alkenyloxy,

[0392] Same or different, indicating

[0393]

[0394] in

[0395] Preferred representation

[0396] Z 51 , Z 52 Each independently represents -CH 2 -CH 2 -、-CH 2 -O-, -CH=CH-, -C≡C-, -COO- or a single bond, preferably -CH 2 -CH 2 -、-CH2 -O- or a single bond, and a single bond is particularly preferred, and

[0397] n is 1 or 2,

[0398] wherein one or more compounds of formula V are different from compounds of formula I.

[0399] The compound of formula V is preferably selected from the compounds of formulae V-1 to V-16:

[0400]

[0401]

[0402] Where R 51 and R 52 has the meaning indicated above.

[0403] R 51 and R 52 Preferably each independently of one another represents a straight-chain alkyl or alkenyl group.

[0404] Preferred LC media comprise one or more compounds of formula V-1, V-3, V-4, V-6, V-9, V-10, V-11, V-13, V-14, and / or V-15.

[0405] The LC media according to the invention very particularly preferably comprise compounds of the formula V-9 and / or IV-1, in particular in an amount of 5 to 30%.

[0406] Preferred compounds of formula V-9 are indicated below:

[0407]

[0408] The LC medium according to the invention particularly preferably comprises a combination of a tricyclic compound of the formula V-9a and / or V-9b with one or more bicyclic compounds of the formula IV-1. The total proportion of the combination of the compounds of the formula V-9a and / or V-9b with one or more compounds selected from the group consisting of the bicyclohexyl compounds of the formula IV-1 is 5 to 40%, very particularly preferably 15 to 35%.

[0409] Particularly preferred LC media comprise compounds V-9a and / or IV-1-1,

[0410]

[0411] The compounds V-9a and IV-1-1 are preferably present in the mixture in a concentration of 5 to 30%, very preferably 10 to 25%, based on the mixture as a whole.

[0412] Preferred LC media comprise at least one compound selected from the group consisting of,

[0413]

[0414]

[0415] Where R 41 , R 42 , R 51 and R 52 has the meaning indicated above. Preferably, in compounds V-6, I and IV, R 41 and R 51 represents an alkyl or alkenyl group having 1 to 6 or 2 to 6 C atoms, respectively, and R 42 and R 52 represents an alkenyl group having 2 to 6 C atoms. Preferably, in compound V-13, R 51 represents an alkyl or alkenyl group having 1 to 6 or 2 to 6 C atoms and R 52 represents an alkyl group having 1 to 6 C atoms.

[0416] In a preferred embodiment of the present invention, the LC medium additionally comprises one or more compounds of the formulae VI-1 to VI-24,

[0417]

[0418]

[0419]

[0420]

[0421] in

[0422] R 61 represents a straight-chain alkyl or alkoxy group having 1 to 6 C atoms, a cycloalkyl group having 3 to 6 C atoms, (O) represents -O- or a single bond, and X represents F, Cl, OCF 3 or OCHF 2 , L x represents H or F, m is 0, 1, 2, 3, 4, 5 or 6, and n is 0, 1, 2, 3 or 4.

[0423] R 61 Preferably, it represents methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy or pentyloxy.

[0424] X preferably represents F or OCH 3 , F is highly preferred.

[0425] The LC media according to the invention preferably comprise the terphenyls of the formulae VI-1 to VI-24 in amounts of 2 to 30% by weight, in particular 5 to 20% by weight.

[0426] Particularly preferred are compounds of formula VI-1, VI-3, VI-19, VI-20, and VI-21, wherein X represents F. In these compounds, R 61 Preferably, it represents an alkyl group, and also an alkoxy group, each of which has 1 to 5 C atoms. 61 Preferably represents an alkyl or alkenyl group, in particular an alkyl group. 61 In the compounds of formulae VI-21 to VI-24, X preferably represents F.

[0427] Terphenyls of the formulae VI-1 to VI-24 are preferably used in the LC media according to the invention if the Δn value of the mixture is to be ≥0.1. Preferred LC media comprise 2 to 20% by weight of one or more terphenyl compounds selected from the compounds of the formulae VI-1 to VI-24.

[0428] In another preferred embodiment of the present invention, the LC medium additionally comprises one or more compounds of the formulae VII-1 to VII-9

[0429]

[0430]

[0431] in

[0432] R 71 Each independently has in formula II A for R 21 One of the meanings indicated, and

[0433] w and x each independently represent 1 to 6.

[0434] Particular preference is given to LC media which comprise at least one compound of the formula VII-9.

[0435] LC medium comprising one or more substances containing tetrahydronaphthyl or naphthyl units, for example compounds of formulae N-1 to N-5,

[0436]

[0437] Where R N1 and R N2 Each independently has a 21 The meanings indicated preferably represent straight-chain alkyl, straight-chain alkoxy or straight-chain alkenyl, and

[0438] ZN1 and Z N2 Independently of each other, it means -C 2 H 4 -, -CH=CH-, -(CH 2 ) 4 -,-(CH 2 ) 3 O-, -O(CH 2 ) 3 -, -CH=CHCH 2 CH 2 -,-CH 2 CH 2 CH=CH-, -CH 2 O-, -OCH 2 -, -COO-, -OCO-, -C 2 F 4 -, -CF=CF-, -CF=CH-, -CH=CF-, -CF 2 O-, -OCF 2 -,-CH 2 - or single key.

[0439] LC medium comprising one or more compounds selected from the group consisting of difluorodibenzochroman compounds of formula BC, chromans of formula CR and fluorinated phenanthrenes of formulae PH-1 and PH-2,

[0440]

[0441]

[0442] in

[0443] R 81 and R 82 Each independently has R 21 The meaning of R 81 and R 82 Preferably, independently of one another, represents an alkyl or alkoxy group having 1 to 6 C atoms, or a cyclic alkyl group having 3 to 6 C atoms,

[0444] c is 0, 1, or 2, and

[0445] Y 1 , Y 2 , Y 3 , Y 4 , each independently of the other, represents H, F, Cl, CF 3 , CHF 2 , CH 3 or OCH 3 .

[0446] The LC media according to the invention preferably comprise the compound of the formula BC, CR, PH-1, PH-2 in an amount of 3 to 20% by weight, in particular in an amount of 3 to 15% by weight.

[0447] Particularly preferred compounds of formula BC and CR are compounds BC-1 to BC-7 and CR-1 to CR-5,

[0448]

[0449]

[0450]

[0451] in

[0452] alkyl and alkyl* each independently represent a straight-chain alkyl group having 1 to 6 C atoms, or a cyclic alkyl group having 3 to 6 C atoms, and

[0453] Alkenyl and alkenyl* each independently of one another represent a straight-chain alkenyl radical having 2 to 6 C atoms.

[0454] Particularly preferred compounds of formula BC are compounds B(A)-2O-O2,

[0455]

[0456] Particularly preferred compounds of formula PH-1, compounds B(P)-2O-O3 and B(P)-2O-O4,

[0457]

[0458] LC medium comprising one or more indane compounds of the formula In,

[0459]

[0460] in

[0461] R 91 , R 92 ,

[0462] R 93 Each independently of one another represents a straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl group having 1 to 6 C atoms, or a cyclic alkyl group having 3 to 6 C atoms, R 92 and R 93 It can also represent halogen, preferably F,

[0463] express

[0464]

[0465] i represents 0, 1 or 2.

[0466] Preferred compounds of formula In are compounds of formulae In-1 to In-16 indicated below:

[0467]

[0468]

[0469]

[0470] Compounds of the formulae In-1, In-2, In-3 and In-4 are particularly preferred.

[0471] The compounds of the formula In and the subformulae In-1 to In-16 are preferably used in the LC media according to the invention in a concentration of ≥5% by weight, in particular from 5 to 30% by weight and very particularly preferably from 5 to 25% by weight.

[0472] LC medium comprising one or more compounds of formulae L-1 to L-8,

[0473]

[0474]

[0475] in

[0476] R L1 and R L2 Each independently has the R 21 The parameter s is 1 or 2.

[0477] The compounds of the formulae L-1 to L-8 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.

[0478] LC medium comprising one or more quaternary compounds selected from the following formulae:

[0479]

[0480] in

[0481] R Q is alkyl, alkoxy, oxaalkyl or alkoxyalkyl having 1 to 9 C atoms, or alkenyl or alkenyloxy having 2 to 9 C atoms, all of which are optionally fluorinated,

[0482] X Qis F, Cl, haloalkyl or alkoxy having 1 to 6 C atoms, or haloalkenyl or alkenyloxy having 2 to 6 C atoms,

[0483] L Q1 To L Q6 are independently H or F, where L Q1 To L Q6 At least one of them is F.

[0484] Preferred compounds of formula Q are those wherein R Q These represent compounds having straight-chain alkyl radicals having 2 to 6 C atoms, very preferably ethyl, n-propyl or n-butyl.

[0485] Preferred compounds of formula Q are those wherein L Q3 and L Q4 Those compounds wherein L is Q3 , L Q4 and L Q1 and L Q2 Those compounds wherein one or both of the compounds are F.

[0486] Preferred compounds of formula Q are those wherein X Q Indicates F or OCF 3 , those compounds of F are very preferred.

[0487] The compound of formula Q is preferably selected from the following sub-formulae,

[0488]

[0489] Where R Q has one of the meanings of the formula Q or one of the preferred meanings given above and below, and is preferably ethyl, n-propyl or n-butyl.

[0490] Particularly preferred are compounds of formula Q1, especially wherein R Q Those compounds which are n-propyl.

[0491] Preferably, the proportion of the compound of the formula Q in the LC medium is >0 to ≤5% by weight, very preferably 0.05 to 2% by weight, more preferably 0.1 to 1% by weight, most preferably 0.1 to 0.8% by weight.

[0492] Preferably, the LC medium contains 1 to 5, preferably 1 or 2, compounds of formula Q.

[0493] Adding quaterphenyl compounds of formula Q to the LC mixture of a polymerizable LC medium enables reduction of ODF inhomogeneities while maintaining high UV absorption, which enables fast and complete polymerisation, enables strong and fast tilt angle generation and improves the UV stability of the LC medium.

[0494] Furthermore, the addition of compounds of formula Q with positive dielectric anisotropy to LC media with negative dielectric anisotropy allows for better control of the dielectric constant ε || and ε ⊥ and in particular enables a high dielectric constant ε to be achieved while keeping the dielectric anisotropy Δε constant. || value, thereby reducing the kickback voltage and reducing image retention.

[0495] The LC medium according to the invention preferably comprises:

[0496] - one or more compounds of the formula I or its subformulae, preferably the formula Ib, preferably in a proportion of 1 to 15%, very preferably 2 to 12%, most preferably 3 to 10%, by weight;

[0497] and / or

[0498] - one or more compounds of formula III, or subformulae thereof, preferably formula III-1 and / or III-6, preferably in a total concentration range of 0.1 to 30%, more preferably 1 to 20%, very preferably 1 to 18%;

[0499] and / or

[0500] - one or more compounds of formula BC, or subformulae thereof, preferably in a total concentration range of 0.1 to 30%, more preferably 1 to 20%, very preferably 1 to 18%;

[0501] and / or

[0502] - one or more compounds of formula PH-1, or subformulae thereof, preferably in a total concentration range of 0.1 to 30%, more preferably 1 to 20%, very preferably 1 to 18%;

[0503] and / or

[0504] - one or more compounds of formula II, or subformulae thereof, preferably formula IIA and / or IIB, and / or IID, preferably in a total concentration range of 25 to 65%, more preferably 30 to 60%, particularly preferably 35 to 55%;

[0505] and / or

[0506] - one or more compounds of formula IV, or subformulae thereof, preferably formulae IV-1, IV-3, and IVa-2, preferably in a total concentration range of 25 to 60%, more preferably 30 to 55%, particularly preferably 35 to 50%;

[0507] and / or

[0508] - one or more compounds of formula V, or subformulae thereof, preferably formula V-9, preferably in a total concentration range of 0.1 to 30%, more preferably 0.25 to 25%, particularly preferably 0.5 to 20%;

[0509] Further preferred embodiments are listed below, wherein the abbreviations used are explained in Table B, wherein n and m are each independently an integer from 1 to 7:

[0510] one or more compounds CCC-nV, in particular CCC-3-V, preferably in a total concentration range of 1 to 15%, preferably 2 to 12%, very preferably 3 to 10%, based on the mixture as a whole;

[0511] and / or

[0512] - one or more compounds B(S)-nO-Om and / or COB(S)-n-Om, in particular B(S)-2O-O4, B(S)-2O-O5, B(S)-2O-O6, and / or COB(S)-2-O4, preferably in a total concentration range of 0.1 to 30%, more preferably 1 to 20%, very preferably 1 to 18%, based on the mixture as a whole;

[0513] and / or

[0514] - one or more compounds B(P)-nO-Om, in particular B(P)-2O-O3, and / or B(P)-2O-O4, preferably in a total concentration range of 0.1 to 30%, more preferably 1 to 20%, very preferably 1 to 18%, based on the mixture as a whole;

[0515] and / or

[0516] - one or more compounds B(A)-nO-Om, in particular B(P)-2O-O2, preferably in a total concentration range of 0.1 to 30%, more preferably 1 to 20%, very preferably 1 to 18%, based on the mixture as a whole;

[0517] and / or

[0518] - one or more compounds Y-nO-Om, CY-n-Om, CPY-n-Om, CCY-n-Om, CCY-Vn-Om, CLY-n-Om, CLOY-n-Om, and / or CAIY-n-Om, in particular Y-4O-O4, CY-3-O2, CPY-3-O2, CCY-3-O2, CCY-5-O2, CLY-3-O2, CLY-3-O3, CLY-4-O2, CLY-5-O2, CLOY-3-O2 and / or CAIY-3-O2, preferably in a total concentration range of 25 to 65%, more preferably 30 to 60%, based on the mixture as a whole;

[0519] and / or

[0520] - one or more compounds CC-nm, CC-nV, CC-n-Vm, and / or CP-n-Om, preferably CC-3-4, CC-3-5, CC-3-V, CC-3-V1, CC-4-V1, and / or CP-3-O2, preferably in a total concentration range of 25 to 60%, more preferably 30 to 55%, particularly preferably 35 to 50%, based on the entire mixture;

[0521] and / or

[0522] - one or more compounds CY-n-Om, in particular CY-3-O4, CY-5-O4 and / or CY-3-O2, preferably in a total concentration range of 5% to 30%, preferably 10% to 20%, based on the entire mixture;

[0523] and / or

[0524] - one or more compounds PY-n-Om, and / or PY-nO-Om, in particular PY-1-O2, PY-2-O2 and / or PY-3-O2, preferably in a total concentration range of 5% to 40%, preferably 10% to 30%, based on the mixture as a whole;

[0525] and / or

[0526] - one or more compounds CPY-n-Om, and / or CPY-Vn-m, in particular CPY-2-O2, CPY-3-O2 and / or CPY-5-O2, preferably in a concentration of >5%, in particular 7% to 20%, based on the mixture as a whole,

[0527] and / or

[0528] one or more compounds CCY-n-Om, preferably CCY-4-O2, CCY-3-O2, CCY-3-O3, CCY-3-O1 and / or CCY-5-O2, preferably in a concentration of >3%, in particular 5 to 15%, based on the mixture as a whole;

[0529] and / or

[0530] one or more compounds CPY-n-Om and CY-n-Om, preferably in a concentration of 10 to 80%, based on the mixture as a whole,

[0531] and / or

[0532] one or more compounds CPY-n-Om and PY-n-Om, preferably CPY-2-O2 and / or CPY-3-O2 and PY-3-O2 or PY-1-O2, preferably in a concentration of 5 to 20%, more preferably 10 to 15%, based on the mixture as a whole,

[0533] and / or

[0534] one or more compounds selected from CCH-13, CCH-23, CCH-34, CCH-35, CCH-301 and CCH-303, preferably in a total concentration of 3 to 40%, preferably 3 to 25%, based on the mixture as a whole,

[0535] and / or

[0536] one or more compounds selected from CC-2-V1, CC-3-V1, CC-3-V2, CC-4-V1, CC-3-V, CC-4-V and CC-5-V, preferably in a total concentration of 3 to 40%, more preferably 5 to 30%, based on the mixture as a whole,

[0537] and / or

[0538] one or more compounds CCP-nm and / or CCP-Vn-m and / or CPP-nm, preferably selected from CCP-3-1, CCP-V-1, CCP-V2-1 and CPP-3-2, preferably in a total concentration of 4 to 35%, preferably 5 to 25%, based on the mixture as a whole,

[0539] and / or

[0540] one or more compounds CLP-nm, CLP-n-Om and / or CLP-Vn-m, preferably selected from CLP-3-1, CLP-3-2, CLP-3-O1, CLP-3-O2 and CLP-V-1, preferably in a total concentration of 1 to 25%, preferably 2 to 15%, based on the mixture as a whole,

[0541] and / or

[0542] one or more compounds selected from PYP-nm, PGIY-n-Om and PGP-n-2V, preferably in a total concentration of 2 to 20%, more preferably 2 to 15%, most preferably 2 to 10%, based on the mixture as a whole,

[0543] and / or

[0544] one or more compounds PP-nm and / or PP-n-nVm, preferably selected from PP-1-3, PP-1-4, PP-1-5, PP-1-2V and PP-1-2V1, preferably in a total concentration of 1 to 15%, preferably 2 to 10%, based on the mixture as a whole,

[0545] and / or

[0546] - the compound PPGU-3-F, preferably in a concentration of 0.1% to 3%, based on the mixture as a whole.

[0547] Advantageously, the liquid-crystalline media according to the invention preferably have a nematic phase from ≤-20°C to ≥70°C, particularly preferably from ≤-30°C to ≥80°C, very particularly preferably from ≤-40°C to ≥90°C.

[0548] The LC media according to the invention have a clearing temperature of 70°C or more, preferably 95°C or more, for example from 95°C to 125°C.

[0549] Here, the expression "has a nematic phase" means on the one hand that no smectic phase and no crystallization is observed at low temperatures at the corresponding temperature and on the other hand that no clearing occurs even when heating from the nematic phase. The investigations at low temperatures are carried out in a flow viscometer at the corresponding temperature and checked by storage for at least 100 hours in test cells with a layer thickness corresponding to the electro-optical application. If the storage stability at a temperature of -20°C in a corresponding test cell is 1000 hours or more, the LC medium is said to be stable at this temperature. At temperatures of -30°C and -40°C, the corresponding times are 500 hours and 250 hours, respectively. At high temperatures, the clearing point is measured in a capillary by conventional methods.

[0550] The liquid crystal mixture preferably has a nematic phase range of at least 60 K and a nematic phase range of at most 30 mm at 20° C. 2 ·s -1 The flow viscosity ν 20 .

[0551] The mixture is nematic at a temperature of -20°C or below, preferably at a temperature of -30°C or below, very preferably at a temperature of -40°C or below.

[0552] The value of the birefringence Δn in the liquid-crystal mixture is generally between 0.07 and 0.16, preferably between 0.08 and 0.15, very preferably between 0.09 and 0.14. In a preferred embodiment of the invention, the LC medium has a birefringence in the range from 0.075 to 0.110, preferably from 0.080 to 0.108, in particular from 0.082 to 0.105.

[0553] The liquid-crystal mixtures according to the invention have a dielectric anisotropy Δε of -1.5 to -8.0, preferably -3.0 to -6.9.

[0554] Rotational viscosity at 20°C γ 1 Preferably, it is ≤245 mPa·s, in particular ≤240 mPa·s. In a preferred embodiment, the rotational viscosity γ at 20°C 1 ≤235mPa·s, especially ≤230mPa·s.

[0555] The liquid-crystal media according to the invention have a relatively low threshold voltage (V 0 They are preferably in the range of 1.7 V to 3.0 V, particularly preferably ≤2.7 V and very particularly preferably ≤2.5 V.

[0556] For the present invention, unless otherwise expressly stated, the term "threshold voltage" refers to the capacitance threshold (V 0 ).

[0557] Furthermore, the liquid-crystalline media according to the invention have high voltage holding ratio values ​​in liquid-crystal cells.

[0558] Typically, 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.

[0559] For the purposes of the present invention, the term "dielectrically positive compound" means a compound with Δε>1.5, the term "dielectrically neutral compound" means a compound with -1.5≤Δε≤1.5, and the term "dielectrically negative compound" means a compound with Δε<-1.5. The dielectric anisotropy of the compounds is determined here by dissolving 10% of the compound in a liquid-crystal host and determining the capacitance of the resulting mixture at 1 kHz with homeotropic surface alignment and with planar surface alignment in at least one test cell, the liquid-crystal cell having in each case a layer thickness of 20 μm. The measuring voltage is typically 0.5 V to 1.0 V, but is always below the capacitance threshold of the respective liquid-crystal mixture under investigation.

[0560] All temperature values ​​indicated in the present invention are in ° C.

[0561] The LC media according to the invention are suitable for all FFS (fringe field switching) and UB-FFS (ultra-brightness FFS) applications with negative Δε. The LC media according to the invention are further suitable for all VA-TFT (vertically aligned thin film transistor) applications, such as VAN (vertically aligned nematic), MVA (multidomain VA), (S)-PVA (super patterned VA), ASV (advanced super view, or axisymmetric VA), PSA (polymer sustained VA) and PS-VA (polymer stabilized VA). They are also suitable for IPS (in-plane switching) applications with negative Δε.

[0562] The nematic LC media in the displays according to the invention generally comprise two components A and B, which themselves consist of one or more individual compounds.

[0563] Component A has a significantly negative dielectric anisotropy and imparts a dielectric anisotropy of ≤-0.5 to the nematic phase.

[0564] The proportion of component A is preferably between 45 and 100%, in particular between 60 and 85%.

[0565] For component A, preference is given to selecting one (or more) individual compounds having a Δε value of ≤−1.5. The smaller the proportion A in the mixture as a whole, the more negative this value must be.

[0566] Component B is a dielectrically neutral compound having -1.5≤Δε≤1.5. In addition, component B has significant nematicity and a lattice density of not more than 30 mm at 20°C. 2 ·s -1 , preferably no more than 25mm 2 ·s -1 The flow viscosity.

[0567] A large number of suitable materials are known to the person skilled in the art from the literature.

[0568] Particularly preferred individual compounds in component B are those having a molecular weight of not more than 18 mm at 20°C. 2 ·s -1 , preferably no more than 12mm 2 ·s -1 Very low viscosity nematic liquid crystal with a flow viscosity of .

[0569] Component B is monotropically or enantiotropically nematic, has no smectic phase, and is capable of preventing the appearance of a smectic phase in the LC medium at low to very low temperatures. For example, if various highly nematic materials are added to a smectic liquid crystal mixture, the nematicity of these materials can be compared by the degree of suppression of the smectic phase achieved.

[0570] The mixture may optionally further comprise a component C comprising compounds having a dielectric anisotropy of Δε≥1.5. These so-called positive compounds are generally present in mixtures of negative dielectric anisotropy in an amount of ≤20% by weight, based on the mixture as a whole.

[0571] Besides the compounds of the formula I and III and the compounds of the formulae IIA, IIB and / or IID, further constituents may be present, for example in amounts of up to 45%, but preferably up to 35%, in particular up to 10%, of the mixture as a whole.

[0572] The further components are preferably selected from nematic or nematic substances, in particular known substances, which are selected from the following classes: azoxybenzene, benzylidene aniline, biphenyl, terphenyl, phenyl benzoate or cyclohexyl benzoate, phenyl cyclohexanecarboxylate or cyclohexyl cyclohexanecarboxylate, phenylcyclohexane, cyclohexylbiphenyl, cyclohexylcyclohexane, cyclohexylnaphthalene, 1,4-dicyclohexylbiphenyl or cyclohexylpyrimidine, phenyldioxane or cyclohexyldioxane, optionally halogenated Benzyl phenyl ether, tolan and substituted cinnamate.

[0573] The most important compounds suitable as constituents of this type of liquid-crystalline phase can be characterized by the formula R

[0574] R R1 -LGER R2 R

[0575] wherein L and E each represent a carbocyclic or heterocyclic ring system, the system being derived from a radical formed from 1,4-disubstituted benzene and cyclohexane rings, 4,4'-disubstituted biphenyls, phenylcyclohexane and cyclohexylcyclohexane systems, 2,5-disubstituted pyrimidines and 1,3-disubstituted Alkanes, 2,6-disubstituted naphthalenes, di- and tetrahydronaphthalenes, quinazolines and tetrahydroquinazolines,

[0576] G represents -CH=CH--N(O)=N-

[0577] -CH=CQ--CH=N(O)-

[0578] -C≡C--CH 2 -CH2 -

[0579] -CO-O--CH 2 -O-

[0580] -CO-S--CH 2 -S-

[0581] -CH=N--COO-Phe-COO-

[0582] -CF 2 O--CF=CF-

[0583] -OCF 2 --OCH 2 -

[0584] -(CH 2 ) 4 --(CH 2 ) 3 O-

[0585] or a CC single bond, Q represents halogen, preferably chlorine, or -CN, and R R1 and R R2 each represents an alkyl, alkenyl, alkoxy, alkoxyalkyl or alkoxycarbonyloxy radical having up to 18, preferably up to 8, carbon atoms, or one of these radicals alternatively represents CN, NC, NO 2 、NCS、CF 3 , SF 5 、OCF 3 , F, Cl or Br.

[0586] In most of these compounds, R R1 and R R2 are different from one another, one of these groups being generally an alkyl or alkoxy group. Other variants of the proposed substituents are also common. Many such substances or also mixtures thereof are commercially available. All these substances can be prepared by methods known from the literature.

[0587] It is self-evident to the person skilled in the art that the VA, IPS or FFS mixtures 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.

[0588] The LC medium preferably has a nematic LC phase.

[0589] In a preferred embodiment, the LC medium contains one or more chiral dopants, preferably in a concentration of 0.01 to 1% by weight, very preferably 0.05 to 0.5% by weight. The chiral dopants are preferably selected from the compounds from Table C below, very preferably from R- or S-1011, R- or S-2011, R- or S-3011, R- or S-4011 and R- or S-5011.

[0590] In another preferred embodiment, the LC medium contains the racemate of one or more chiral dopants, which are preferably selected from the chiral dopants mentioned in the previous paragraph.

[0591] In another preferred embodiment of the present invention, the LC medium contains one or more additional stabilizers.

[0592] Preferred stabilizers are selected from compounds of formula H

[0593]

[0594] in

[0595] Ar represents an aromatic or heteroaromatic hydrocarbon radical having 4 to 40 C atoms, preferably 6 to 30 C atoms;

[0596] Sp represents a spacer group;

[0597] R S represents H, alkyl having 1 to 12 C atoms or alkenyl having 2 to 12 C atoms;

[0598] Z S Indicates -O-, -C(O)O-, -(CH 2 ) z -or-(CH 2 ) z O-, or single bond;

[0599] HA means

[0600] R H Indicates H, O, CH 3 , OH or OR S , preferably H or O;

[0601] R S1 , R S2 , R S3 and R S4 represent, identically or differently, an alkyl radical having 1 to 6 C atoms, preferably having 1 to 3 C atoms, very preferably CH 3 ;

[0602] G stands for H or RS or group Z S -HA;

[0603] z is an integer from 1 to 6; and

[0604] q is 3 or 4.

[0605] Compounds of formula H are described in EP3354710 A1 and EP3354709 A1.

[0606] Preferred compounds of formula H are selected from formula H-1, H-2 and H-3:

[0607]

[0608]

[0609] Where R H has the meaning 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, and Sp denotes a spacer group, preferably an alkylene group having 1 to 12 C atoms, in which one or more non-adjacent -CH 2 The - group may be replaced by -O-.

[0610] Preferred compounds of formula H-1 are those of formula H-1-1:

[0611]

[0612] Where R H has 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.

[0613] Very preferred compounds of formula H-1-1 are those of formula H-1-1-1:

[0614]

[0615] Preferred compounds of formula H-2 are those of formula H-2-1:

[0616]

[0617] Where R H has the meanings given above and preferably denotes H or O, and n2 is, identically or differently, preferably identically, an integer from 1 to 12 on each occurrence, preferably 2, 3, 4, 5 or 6, very preferably 3, and R S Identically or differently, preferably identically, on each occurrence represents alkyl having 1 to 6 C atoms, preferably n-butyl.

[0618] Very preferred compounds of formula H-2-1 are those of formula H-2-1-1:

[0619]

[0620] Preferred compounds of formula H-3 are selected from formula H-3-1:

[0621]

[0622] Where Sp and R H has the meaning given above, and R H Preferably it represents H or O, and n is an integer from 0 to 12, preferably 5, 6, 7, 8 or 9, very preferably 7.

[0623] Further preferred stabilizers are selected from the group consisting of formulae ST-1 to ST-18:

[0624]

[0625]

[0626]

[0627] in

[0628] R ST represents H, an alkyl or alkoxy group having 1 to 15 C atoms, wherein one or more CH 2 The groups can also be independently replaced by -C≡C-, -CF 2 O-, -OCF 2 -, -CH=CH-,

[0629]

[0630] -O-, -CO-O-, -O-CO- are substituted in such a way that the O atoms are not directly connected to one another, and wherein, in addition, one or more H atoms may be replaced by halogen,

[0631] In each occurrence, the same or different, means

[0632]

[0633] Z ST Each independently represents -CO-O-, -O-CO-, -CF 2 O-, -OCF 2 -,-CH 2 O-, -OCH 2 -,-CH 2 -,-CH2 CH 2 -,-(CH 2 ) 4 -,-CH=CH-,-CH 2 O-, -C 2 F 4 -,-CH 2 CF 2 -, -CF 2 CH 2 -, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C- or single bond,

[0634] L 1 and L 2 Each independently represents F, Cl, CH 3 , C.F. 3 or CHF 2 ,

[0635] p represents 0, 1 or 2,

[0636] q means 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0637] Preferred compounds of formula ST are those selected from formula ST-3, and in particular:

[0638]

[0639] Where n=1, 2, 3, 4, 5, 6 or 7, preferably n=3

[0640]

[0641] Where n=1, 2, 3, 4, 5, 6 or 7, preferably n=3

[0642]

[0643] wherein n=1, 2, 3, 4, 5, 6 or 7, preferably n=1 or 7

[0644]

[0645] Where q=8.

[0646]

[0647] In the compounds of formula ST-2a, n preferably represents 7.

[0648] Very preferred stabilizers are selected from the compounds of formula ST-2a-1, ST-3a-1, ST-3a-2, ST-3b-1, ST-3b-2, ST-7, ST-8-1, ST-9-1 and ST-12:

[0649]

[0650]

[0651] In another preferred embodiment, the LC medium comprises one or more stabilizers selected from Table D below.

[0652] Preferably, the proportion of stabilizer in the LC medium is from 10 to 500 ppm, very preferably from 20 to 100 ppm.

[0653] The LC medium according to the present invention may additionally comprise one or more further components or additives, which are preferably selected from the group consisting of, but not limited to, comonomers, chiral dopants, polymerization initiators, inhibitors, stabilizers, surfactants, wetting agents, lubricants, dispersants, hydrophobic agents, binders, flow improvers, defoamers, deaerators, diluents, reactive diluents, auxiliaries, colorants, dyes, pigments and nanoparticles.

[0654] Furthermore, it is possible to add, for example, 0 to 15% by weight of pleochroic dyes to the LC medium, in addition to nanoparticles, conductive salts, preferably ethyldimethyldodecyl 4-hexyloxyammonium benzoate, tetrabutylammonium tetraphenylborate or complex salts of crown ethers (see, for example, Haller et al., Mol. Cryst. Liq. Cryst. 24 , 249-258 (1973)) for improving the electrical conductivity, or adding substances for modifying the dielectric anisotropy, viscosity and / or orientation of the nematic phase. Such substances are described, for example, in DE-A 22 09 127, 2240 864, 23 21 632, 23 38 281, 24 50 088, 26 37 430 and 28 53 728.

[0655] The individual components of the preferred embodiments of the LC media according to the invention listed above are known or the processes for preparing them are available from the prior art to the person skilled in the relevant art, since they are based on standard processes described in the literature. The corresponding compounds of the formula CY are described, for example, in EP-A-0 364 538. The corresponding compounds of the formula ZK are described, for example, in DE-A-26 36 684 and DE-A-3321 373.

[0656] The LC media which can be used according to the invention are prepared in a manner conventional per se, for example by mixing one or more of the above-mentioned compounds with one or more polymerizable compounds as defined above, and optionally with further liquid-crystalline compounds and / or additives. Usually, the desired amount of the components used in smaller amounts is dissolved in the components making up the main constituents, this being advantageously done at elevated temperature. It is also possible to mix the solutions of the components in an organic solvent, for example acetone, chloroform or methanol, and to remove the solvent again, for example by distillation after thorough mixing. The invention also relates to a process for the preparation of the LC media according to the invention.

[0657] It goes without saying to the person skilled in the art that the LC media according to the invention can also comprise compounds in which H, N, O, Cl, F are replaced by corresponding isotopes, for example deuterium. DETAILED DESCRIPTION

[0658] The following examples illustrate the present invention but do not limit the present invention. However, they show preferred mixture concepts to those skilled in the art, as well as the compounds preferably used and their respective concentrations, and their combinations with each other. In addition, the examples illustrate which properties and combinations of properties are obtainable.

[0659] For the present invention and in the following examples, the structures of the liquid-crystal compounds are indicated with the aid of acronyms. Unless otherwise indicated, the conversion into chemical formulae is carried out according to the following Tables A.1 to A.3. All radicals C n H 2n+1 , C m H 2m+1 and C l H 2l+1 or C n H 2n , C m H 2m and C l H 2l is a straight-chain alkyl group or alkylene group having n, m and 1 C atoms, respectively, in each case. Preferably, n, m and 1 are independently 1, 2, 3, 4, 5, 6 or 7. Table A.1 shows the ring element codes of the core structure of the compounds, Table A.2 lists the bridging units, and Table A.3 lists the meanings of the symbols of the left-hand and right-hand end groups of the molecules. The acronyms consist of the code for the ring element with the optional linking group, followed by a first hyphen, and the code for the left-hand end group, and a second hyphen and the code for the right-hand end group.

[0660] Table A.1: Ring elements

[0661]

[0662]

[0663]

[0664] Table A.2: Bridging units

[0665]

[0666] Table A.3: Terminal groups

[0667]

[0668]

[0669] wherein n and m are each integers, and the three dots "..." are placeholders for other abbreviations taken from the table.

[0670] Table B shows exemplary structures of compounds along with their respective abbreviations.

[0671] Table B

[0672] In Table B, n, m, k and l are each independently of one another an integer, preferably 1 to 9, preferably 1 to 7, k and l may also be 0, and preferably 0 to 4, more preferably 0 or 2, and most preferably 2, n is preferably 1, 2, 3, 4 or 5, or in the combination "-nO-", n is preferably 1, 2, 3 or 4, very preferably 2 or 4, m is preferably 1, 2, 3, 4 or 5, or in the combination "-Om", m is preferably 1, 2, 3 or 4, more preferably 2 or 4. The combination "-nVm" is preferably "2V1". (O)C m H 2m+1 It means C m H 2m+1 or OC m H 2m+1 .

[0673]

[0674]

[0675]

[0676]

[0677]

[0678]

[0679]

[0680]

[0681]

[0682]

[0683]

[0684]

[0685]

[0686]

[0687]

[0688]

[0689]

[0690]

[0691]

[0692]

[0693]

[0694]

[0695] In a preferred embodiment of the present invention, the LC media according to the invention comprise one or more of the following compounds selected from the compounds from Table B.

[0696] Table C

[0697] Table C shows possible chiral dopants which can be added to the LC media according to the invention.

[0698]

[0699]

[0700] The LC medium preferably comprises 0 to 10% by weight, in particular 0.01 to 5% by weight, particularly preferably 0.1 to 3% by weight, of dopant. The LC medium preferably comprises one or more dopants selected from the compounds from Table C.

[0701] Table D

[0702] Table D shows possible stabilizers which can be added to the LC media according to the invention. wherein n represents an integer from 1 to 12, preferably 1, 2, 3, 4, 5, 6, 7 or 8, and no terminal methyl groups are shown.

[0703]

[0704]

[0705]

[0706]

[0707]

[0708]

[0709]

[0710] The LC medium preferably comprises 0 to 10% by weight, in particular 1 ppm to 5% by weight, particularly preferably 1 ppm to 1% by weight, of stabilizer. The LC medium preferably comprises one or more stabilizers selected from the compounds from Table D.

[0711] Example

[0712] The following examples explain the present invention without limiting it. However, they show preferred mixture concepts and preferably used compounds and their corresponding concentrations and their combinations with each other to those skilled in the art. In addition, the examples illustrate obtainable properties and property combinations.

[0713] In addition, the following abbreviations and symbols are used:

[0714] V 0 represents the threshold voltage at 20°C, capacitive [V],

[0715] n e represents the extraordinary refractive index at 20°C and 589nm,

[0716] n o represents the ordinary refractive index at 20°C and 589nm,

[0717] △n represents the optical anisotropy at 20°C and 589nm,

[0718] ε ⊥ represents the dielectric constant perpendicular to the director at 20°C and 1kHz,

[0719] ε|| represents the dielectric constant parallel to the director at 20°C and 1kHz,

[0720] Δε represents the dielectric anisotropy at 20°C and 1kHz,

[0721] cl.p., T(N,I) represents the clearing point [℃],

[0722] γ 1 represents the rotational viscosity at 20°C [mPa·s],

[0723] K 1 represents the elastic constant at 20°C, the “bending” deformation [pN],

[0724] K 2 represents the elastic constant at 20°C, "twist" deformation [pN],

[0725] K 3 represents the elastic constant at 20°C, "bending" deformation [pN],

[0726] K 平均 represents the average elastic constant [pN] at 20°C and is defined in this paper as K 平均 ≡( 3 / 2 K 1 +K 3 ) / 3≈(K 1 +K 2 +K 3 ) / 3,

[0727] LTS stands for the low temperature stability of the phase, which is determined in a test cell.

[0728] VHR stands for voltage holding ratio

[0729] Unless expressly stated otherwise, all concentrations in the present application are given as percentages by weight and relate to the respective entire mixture, which comprises all solid or liquid-crystalline components (without solvent).

[0730] Unless otherwise stated, all temperature values ​​indicated in this application, such as melting point T(C,N), transition from smectic phase (S) to nematic phase (N) T(S,N) and clearing point T(N,I) are expressed in degrees Celsius (°C). Mp stands for melting point, cl.p. = clearing point. In addition, C = liquid crystal phase, N = nematic phase, S = smectic phase and I = isotropic phase. The data between these symbols represent transition temperatures.

[0731] All physical properties are and have been determined according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals" Status November 1997, Merck KGaA, Germany, and are valid for a temperature of 20°C, with Δn measured at 589 nm and Δε measured at 1 kHz, unless expressly stated otherwise in each case.

[0732] The term "threshold voltage" as used in the present invention relates to the capacitive threshold (V 0 ), which is also referred to as the Freedericks threshold unless otherwise stated. In the embodiments, the optical threshold is also generally for a relative contrast ratio of 10% (V 10 ) given.

[0733] Unless otherwise stated, the process for polymerising the polymerisable compounds in a PSA display as described above and below is carried out at a temperature at which the LC medium exhibits a liquid crystal phase, preferably a nematic phase, and most preferably at room temperature.

[0734] Unless otherwise stated, the methods for preparing the test cells and measuring their electro-optical and other properties were performed by the methods described below or methods analogous thereto.

[0735] The polymerizable compound is polymerized in the display or test cell by irradiation with UV light of defined intensity for a pre-specified time while applying a voltage (typically 10 V to 30 V AC, 1 kHz) to the display.

[0736] 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.

[0737] Unless otherwise stated, the term "tilt angle" means the angle between the LC director and the substrate, and "LC director" means the preferred orientation direction of the optical principal axes of the LC molecules in a layer with uniformly oriented LC molecules, which in the case of rod-shaped (calamitic) uniaxial positively birefringent LC molecules corresponds to their molecular long axes.

[0738] Example 1

[0739] Nematic LC mixture N1 was prepared as follows.

[0740]

[0741] To mixture N1 was added 100 ppm of stabilizer H-1-1-1.

[0742]

[0743] Example 2

[0744] Nematic LC mixture N2 was prepared as follows.

[0745]

[0746] To mixture N2, 150 ppm of stabilizer ST-3a-1 were added.

[0747]

[0748] Example 3

[0749] Nematic LC mixture N3 was prepared as follows.

[0750]

[0751] To mixture N3, 150 ppm of stabilizer ST-3b-1 were added.

[0752]

[0753] Example 4

[0754] Nematic LC mixture N4 was prepared as follows.

[0755]

[0756] To mixture N4 was added 50 ppm of stabilizer H-2-1-1.

[0757]

[0758] Example 5

[0759] Nematic LC mixture N5 was prepared as follows.

[0760]

[0761] To mixture N5, 100 ppm of stabilizer ST-8-1 was added.

[0762]

[0763] Example 6

[0764] Nematic LC mixture N6 was prepared as follows.

[0765]

[0766] To mixture N6, 50 ppm of stabilizer ST-9-1 was added.

[0767]

[0768] Example 7

[0769] Nematic LC mixture N7 was prepared as follows.

[0770]

[0771] To mixture N7, 50 ppm of stabilizer ST-12 was added.

[0772]

[0773] Example 8

[0774] Nematic LC mixture N8 was prepared as follows.

[0775]

[0776] To mixture N8, 150 ppm of stabilizer ST-3a-2 were added.

[0777]

[0778] Example 9

[0779] Nematic LC mixture N9 was prepared as follows.

[0780]

[0781] To mixture N9 was added 150 ppm of stabilizer ST-3b-2.

[0782]

[0783] Example 10

[0784] Nematic LC mixture N10 was prepared as follows.

[0785]

[0786] To mixture N10, 100 ppm of stabilizer ST-7 was added.

[0787]

[0788] Embodiment 11

[0789] Nematic LC mixture N11 was prepared as follows.

[0790]

[0791] To mixture N11, 100 ppm of stabilizer H-1-1-1 were added.

[0792] Example 12

[0793] Nematic LC mixture N12 was prepared as follows.

[0794]

[0795] To mixture N12, 150 ppm of stabilizer ST-3a-1 were added.

[0796] Embodiment 13

[0797] Nematic LC mixture N13 was prepared as follows.

[0798]

[0799]

[0800] To mixture N13, 150 ppm of stabilizer ST-3b-1 were added.

[0801] Embodiment 14

[0802] Nematic LC mixture N14 was prepared as follows.

[0803]

[0804]

[0805] Where B(S)-4O-O1(c5) is

[0806]

[0807] To mixture N14, 50 ppm of stabilizer H-2-1-1 were added.

[0808] Embodiment 15

[0809] Nematic LC mixture N15 was prepared as follows.

[0810]

[0811] To mixture N15, 100 ppm of stabilizer ST-8-1 was added.

[0812] Example 16

[0813] Nematic LC mixture N16 was prepared as follows.

[0814]

[0815] To mixture N16, 50 ppm of stabilizer ST-9-1 were added.

[0816] Embodiment 17

[0817] Nematic LC mixture N17 was prepared as follows.

[0818]

[0819]

[0820] To mixture N17, 50 ppm of stabilizer ST-12 was added.

[0821] Embodiment 18

[0822] Nematic LC mixture N18 was prepared as follows.

[0823]

[0824]

[0825] To mixture N18, 150 ppm of stabilizer ST-3a-2 were added.

[0826] Embodiment 19

[0827] Nematic LC mixture N19 was prepared as follows.

[0828]

[0829]

[0830] To mixture N19, 150 ppm of stabilizer ST-3b-2 were added.

[0831] Embodiment 20

[0832] Nematic LC mixture N20 was prepared as follows.

[0833]

[0834] To mixture N20, 50 ppm of stabilizer ST-7 was added.

[0835] Embodiment 21

[0836] Nematic LC mixture N21 was prepared as follows.

[0837]

[0838]

[0839] To mixture N21, 100 ppm of stabilizer H-1-1-1 were added.

[0840] Embodiment 22

[0841] Nematic LC mixture N22 was prepared as follows.

[0842]

[0843]

[0844] To mixture N22, 150 ppm of stabilizer ST-3a-1 were added.

[0845] Embodiment 23

[0846] Nematic LC mixture N23 was prepared as follows.

[0847]

[0848] To mixture N23, 150 ppm of stabilizer ST-3b-1 were added.

[0849] Embodiment 24

[0850] Nematic LC mixture N24 was prepared as follows.

[0851]

[0852] To mixture N24, 50 ppm of stabilizer H-2-1-1 was added.

[0853] Embodiment 25

[0854] Nematic LC mixture N25 was prepared as follows.

[0855]

[0856]

[0857] To mixture N25, 100 ppm of stabilizer ST-8-1 was added.

[0858] Embodiment 26

[0859] Nematic LC mixture N26 was prepared as follows.

[0860]

[0861]

[0862] Where B(S)-1V1O-O1(c5) is

[0863]

[0864] To mixture N26, 50 ppm of stabilizer ST-9-1 was added.

[0865] Embodiment 27

[0866] Nematic LC mixture N27 was prepared as follows.

[0867]

[0868]

[0869] To mixture N27, 50 ppm of stabilizer ST-12 was added.

[0870] Embodiment 28

[0871] Nematic LC mixture N28 was prepared as follows.

[0872]

[0873] To mixture N28, 150 ppm of stabilizer ST-3a-2 were added.

[0874] Embodiment 29

[0875] Nematic LC mixture N29 was prepared as follows.

[0876]

[0877] To mixture N29, 150 ppm of stabilizer ST-3b-2 were added.

[0878] Embodiment 30

[0879] Nematic LC mixture N30 was prepared as follows.

[0880]

[0881]

[0882] To mixture N30, 100 ppm of stabilizer ST-7 was added.

[0883] Embodiment 31

[0884] Nematic LC mixture N31 was prepared as follows.

[0885]

[0886]

[0887] To mixture N31 was added 100 ppm of stabilizer H-1-1-1.

[0888] Embodiment 32

[0889] Nematic LC mixture N32 was prepared as follows.

[0890]

[0891] To mixture N32, 150 ppm of stabilizer ST-3a-1 were added.

[0892] Embodiment 33

[0893] Nematic LC mixture N33 was prepared as follows.

[0894]

[0895] To mixture N33, 150 ppm of stabilizer ST-3b-1 were added.

[0896] Embodiment 34

[0897] Nematic LC mixture N34 was prepared as follows.

[0898]

[0899]

[0900] To mixture N34 was added 50 ppm of stabilizer H-2-1-1.

[0901] Embodiment 35

[0902] Nematic LC mixture N35 was prepared as follows.

[0903]

[0904]

[0905] To mixture N35, 100 ppm of stabilizer ST-8-1 was added.

[0906] Embodiment 36

[0907] Nematic LC mixture N36 was prepared as follows.

[0908]

[0909] To mixture N36 was added 50 ppm of stabilizer ST-9-1.

[0910] Embodiment 37

[0911] Nematic LC mixture N37 was prepared as follows.

[0912]

[0913] To mixture N37, 50 ppm of stabilizer ST-12 was added.

[0914] Embodiment 38

[0915] Nematic LC mixture N38 was prepared as follows.

[0916]

[0917]

[0918] To mixture N38, 150 ppm of stabilizer ST-3a-2 were added.

[0919] Embodiment 39

[0920] Nematic LC mixture N39 was prepared as follows.

[0921]

[0922] To mixture N39, 150 ppm of stabilizer ST-3b-2 were added.

[0923] Embodiment 40

[0924] Nematic LC mixture N40 was prepared as follows.

[0925]

[0926] To mixture N40, 100 ppm of stabilizer ST-7 was added.

[0927] Embodiment 41

[0928] Nematic LC mixture N41 was prepared as follows.

[0929]

[0930]

[0931] To mixture N41, 100 ppm of stabilizer H-1-1-1 were added.

[0932] Embodiment 42

[0933] Nematic LC mixture N42 was prepared as follows.

[0934]

[0935]

[0936] To mixture N42, 150 ppm of stabilizer ST-3a-1 were added.

[0937] Embodiment 43

[0938] Nematic LC mixture N43 was prepared as follows.

[0939]

[0940]

[0941] To mixture N43, 150 ppm of stabilizer ST-3b-1 were added.

[0942] Embodiment 44

[0943] Nematic LC mixture N44 was prepared as follows.

[0944]

[0945] To mixture N44, 50 ppm of stabilizer H-2-1-1 was added.

[0946] Embodiment 45

[0947] Nematic LC mixture N45 was prepared as follows.

[0948]

[0949] To mixture N45, 100 ppm of stabilizer ST-8-1 was added.

[0950] Embodiment 46

[0951] A polymerizable mixture was prepared by adding 0.3% of polymerizable compound RM-171 to the mixture of Example 1.

[0952]

[0953] Embodiment 47

[0954] A polymerizable mixture was prepared by adding 0.3% of polymerizable compound RM-1 to the mixture of Example 2.

[0955]

[0956] Embodiment 48

[0957] A polymerizable mixture was prepared by adding 0.3% of polymerizable compound RM-35 to the mixture of Example 3.

[0958]

[0959] Embodiment 49

[0960] A polymerizable mixture was prepared by adding 0.3% of polymerizable compound RM-172 to the mixture of Example 4.

[0961]

[0962] Embodiment 50

[0963] A polymerizable mixture was prepared by adding 0.4% of polymerizable compound RM-64 to the mixture of Example 5.

[0964]

[0965] Embodiment 51

[0966] Nematic LC mixture N51 was prepared as follows.

[0967]

[0968] To mixture N51 was added 100 ppm of stabilizer H-1-1-1.

[0969] Embodiment 52

[0970] Nematic LC mixture N52 was prepared as follows.

[0971]

[0972]

[0973] To mixture N52, 150 ppm of stabilizer ST-3a-1 were added.

[0974] Embodiment 53

[0975] Nematic LC mixture N53 was prepared as follows.

[0976]

[0977] To mixture N53 was added 100 ppm of stabilizer ST-8-1.

[0978] Embodiment 54

[0979] Nematic LC mixture N54 was prepared as follows.

[0980]

[0981] To mixture N54 was added 50 ppm of stabilizer ST-9-1.

Claims

1. A liquid crystal medium comprising one or more compounds of formula I and One or more compounds of formula III and / or One or more compounds of formula BC and / or One or more compounds of formula PH-1 in R 11 , R 31 , R 32 , R 81 , and R 82 each independently of one another represents H, alkyl or alkoxy having 1 to 15 C atoms, wherein one or more -CH2- groups in these radicals can each independently of one another be -C≡C-, -CF2O-, -OCF2-, -CH=CH-, 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, R 12 denotes an alkenyl group having 2 to 12 C atoms, A 3 at each occurrence, independently of one another, denotes a 1,4-phenylene radical in which one or two CH groups may be replaced by N, or a 1,4-cyclohexylene or 1,4-cyclohexenylene radical in which one or two non-adjacent CH2 groups may be replaced by -O- or -S-, where the radicals may be mono- or polysubstituted by halogen atoms, n represents 0, 1 or 2, Z 3 represents, independently of one another, at each occurrence -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -CH=CH-, -C≡C- or a single bond, L 31 and L 32 , each independently of one another, represents F, Cl, CF3 or CHF2, and Y 1 , Y 2 , Y 3 , Y 4 , each independently of one another, represents H, F, Cl, CF3, CHF2, CH3 or OCH3.

2. A liquid crystal medium according to claim 1, wherein the medium comprises one or more compounds selected from the group consisting of compounds of formula III-1 and / or III-6 The radicals occurring therein have the same meanings as given under formula III.

3. A liquid-crystalline medium according to claim 1 , wherein the medium comprises one or more compounds selected from the group consisting of formulae IIA, IIB, IIC, IID, IIE and IIF, where the individual radicals, identically or differently on each occurrence and independently of one another, have the following meanings: R 21 , R 22 represents H, an alkyl, alkoxy or alkenyl radical having up to 15 C atoms, which is unsubstituted or monosubstituted by F, Cl, CN or CF3, and wherein, in addition, one or more CH2 groups in these radicals may also be replaced by -O-, -S-, -C≡C-, -CF2O-, -OCF2-, -OC-O-, -O-CO- Replace in such a way that O and / or S atoms are not directly connected to each other, L 1 To L 4 is F, Cl, CF3 or CHF2, Y is H, F, Cl, CF3, CHF2 or CH3, Z 1 , Z 2 is a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF-, -CH=CHCH2O, p is 0, 1, or 2, and q is 0 or 1.

4. A liquid-crystalline medium according to any one of claims 1 to 3, wherein the medium comprises one or more compounds of the formula IIIA Where R 31 , R 32 , A 3 , Z 3 , L 31 , L 32 , Y 1 , Y 2 , Y 3 , Y 4 , and n have the meanings given for formula III.

5. A liquid-crystalline medium according to any one of claims 1 to 4, wherein the medium comprises one or more compounds of formula IV in R 41 represents an unsubstituted alkyl group having 1 to 7 C atoms, or a cyclic alkyl group having 3 to 6 C atoms or an unsubstituted alkenyl group having 2 to 7 C atoms, and R 42 represents an unsubstituted alkyl group having 1 to 7 C atoms, or a cyclic alkyl group having 3 to 6 C atoms, or an unsubstituted alkoxy group having 1 to 6 C atoms, or an unsubstituted alkenyl group having 2 to 7 C atoms.

6. Liquid-crystalline medium according to claim 5, wherein the medium comprises one or more compounds of the formula IV-1 and IV-3, in Alkyl and alkyl*, independently of one another, denote an alkyl group having 1 to 7 C atoms or a cyclic alkyl group having 3 to 6 C atoms, and Alkenyl is an alkenyl radical having 2 to 7 C atoms.

7. A liquid-crystalline medium according to claim 5, wherein the medium comprises one or more compounds of the formula IVa-2, in Alkyl and alkyl*, independently of one another, denote a straight-chain alkyl group having 1 to 6 C atoms or a cyclic alkyl group having 3 to 6 C atoms.

8. A liquid-crystalline medium according to any one of claims 1 to 7, wherein the medium comprises one or more compounds of the formula V in R 51 , R 52 represents an alkyl group having 1 to 7 C atoms, or a cyclic alkyl group having 3 to 6 C atoms, an alkoxy group having 1 to 7 C atoms, or an alkoxyalkyl group, an alkenyl group or an alkenyloxy group having 2 to 7 C atoms, Same or different, indicating 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; wherein one or more compounds of formula V are different from formula I. 9 . The liquid-crystalline medium according to claim 1 , wherein the medium comprises one or more compounds of the formulae VI-1 to VI-25.

10. Liquid-crystalline medium according to any one of claims 1 to 9, wherein the medium comprises one or more compounds of the formulae CR and PH-2.

11. The liquid crystal medium according to any one of claims 1 to 10, wherein the liquid crystal medium further comprises one or more additives selected from stabilizers, chiral dopants, polymerization initiators and self-aligning additives.

12. A liquid crystal display comprising a liquid crystal medium according to any one of claims 1 to 11.

13. The liquid crystal medium according to claim 12, wherein the display is VA, IPS, FFS, PS-VA, PS-IPS, PS-FFS, UB-FFS or UV 2 A display.

14. Use of a liquid-crystalline medium according to any one of claims 1 to 11 in energy-saving LC displays.

15. A process for preparing a liquid-crystalline medium according to any one of claims 1 to 11, comprising the step of mixing one or more compounds of the formulae I and III with one or more compounds selected from the group consisting of formulae II and / or IV, optionally with further LC compounds and / or additives.

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