Liquid crystal medium

Abstract

The present invention relates to a liquid crystal (LC) medium or a liquid crystal 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, in particular energy-saving LC displays, comprising said LC medium, and 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, in particular in fringing field switching mode LC displays, in particular in fringing field switching mode LC displays. And a method of manufacturing the LC display.

Description

Technical Field

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

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

[0003] Thus, so-called FFS ("fringe field switching") displays have been reported (see, inter alia, SH Jung et al., Jpn. J. Appl. Phys., Vol. 43, No. 3, 2004, 1028), which contain two electrodes on the same substrate, one of which is structured in a comb-like manner and the other is not structured. Strong so-called "fringe fields" are thereby generated, i.e. strong electric fields close to the edges of the electrodes and electric fields with both strong vertical and strong horizontal components throughout the 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 for the molecules of the LC medium.

[0004] FFS displays can operate 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 ("TFTs")), while in the case of passive matrix displays, the individual pixels are typically addressed by multiplexing methods, as is known in the art.

[0005] In addition, a new type of FFS display has been disclosed (referred to as "ultra-bright FFS (UB-FFS) mode display", see SH Lee et al., Appl. Phys. Lett. 73 (20), 1998, 2882-2883 and SH Lee et al., Liquid Crystals 39 (9), 2012, 1141-1148) which has a similar electrode design and layer thickness as the FFS display, but contains a layer of LC medium with negative dielectric anisotropy instead of LC medium with positive dielectric anisotropy. Compared with LC medium with positive dielectric anisotropy, LC medium with negative dielectric anisotropy shows a more favorable director orientation with less tilt and more twisted orientation, and therefore, these displays have higher transmittance. The display also includes an alignment layer, preferably polyimide, disposed on at least one substrate in contact with the LC medium and inducing a planar alignment of the LC molecules of the LC medium. These displays require a highly reliable LC medium.

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

[0007] Also known are so-called IPS ("in-plane switching") displays, 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 a crossed 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 layer plane.

[0008] In the latest types of VA displays, the uniform alignment of the LC molecules is confined to a plurality of relatively small domains within the LC cell. Disclinations, also called tilted domains, may exist between these domains. VA displays with tilted domains have a greater viewing angle independence of the contrast and greyscale shades than conventional VA displays. Furthermore, displays of this type are easier to produce, since additional treatment of the electrode surface, for example by rubbing, is no longer necessary to uniformly align the molecules in the on state. Instead, the preferential direction of the tilt or pre-tilt 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 refers to the performance quality of a display over a period of time and under different stress loads (e.g. light load, temperature, humidity or voltage) leading to display defects such as image sticking (area and line image sticking), display unevenness, dirt (yogore), etc., and is 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 of the maintenance of 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 interaction of LC molecules with the polyimide of the alignment layer, whereby ions are extracted from the polyimide alignment layer and where LC molecules with negative dielectric anisotropy extract such ions more efficiently.

[0012] This leads to new requirements for the LC media 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 voltages, multiple gray levels, high contrast and wide viewing angles and reduced image sticking.

[0013] Therefore, in displays known from the prior art, undesirable effects such as so-called "image sticking" or "image burning" 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, this "image sticking" can occur if LC media with a low VHR are used. The UV component of sunlight or backlighting can lead to undesired decomposition reactions of the LC molecules therein and thus initiate the generation of ionic or radical impurities. These can accumulate in particular at the electrodes or alignment layers, where they can reduce the effectively applied voltage.

[0015] It was therefore an object of the present invention to provide improved LC media for FFS-, VA- or IPS-displays which do not exhibit the abovementioned disadvantages, or exhibit them only to a small extent, and have improved properties. It was a further object of the present invention to provide FFS-, VA- and IPS-displays having good transmittance, high reliability, VHR values ​​(especially after backlight exposure), high specific resistance, a large operating temperature range, short response times (even at low temperatures), low threshold voltage, a wide range of gray levels, high contrast and wide viewing angles, and reduced image sticking.

[0016] Contrast ratio is defined as the ratio of the brightness of the lightest shade (white) to the brightness of the darkest shade (black) that the system can produce, i.e. the ratio of transmittance (white level) to the scattering parameter (dark level). avg and low Δn) can significantly improve the contrast. avg A LC mixture with a low Δn is very effective for realizing high contrast displays. Another object of the present invention is to provide a LC mixture with a very high clearing point, an advantageously high average elastic constant K avg and a LC mixture with a relatively low birefringence Δn while still maintaining a relatively low rotational viscosity γ1.

[0017] It was found that one or more of these objects can be achieved by providing the LC media disclosed and claimed hereinafter. Summary of the invention

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

[0019]

[0020] and

[0021] One or more compounds of formula IB

[0022]

[0023] in

[0024] R A1 , R A2 , R B1 and R B2 each independently of one another represents H, a straight-chain or branched alkyl or alkoxy radical having 1 to 15 C atoms, preferably having 1 to 7 C atoms, wherein one or more -CH2- radicals in these radicals may each independently of one another be replaced in such a way that the O atoms are not directly connected to one another -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO-, wherein one or more H atoms may be replaced by halogen,

[0025] express

[0026]

[0027]

[0028] Z 1 ,Z 2Each independently represents a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF-, -CH=CHCH2O, Y represents H or CH3,

[0029] n represents 0 or 1.

[0030] The invention further relates to an LC display comprising a liquid-crystalline medium as described above and below, in particular a VA, IPS, FFS, PS-VA, PS-IPS, PS-FFS, UB-FFS or UV 2 A display.

[0031] The invention also relates to a liquid-crystalline medium as described above and below in VA, IPS, FFS, PS-VA, PS-IPS, PS-FFS, UB-FFS or UV 2 A Use in display.

[0032] The present invention furthermore relates to a process for the preparation of an LC medium as described above and below, comprising the step of mixing one or more compounds of the formula IA with one or more compounds of the formula IB and optionally with further LC compounds and / or additives.

[0033] The invention also 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 substrates of the display.

[0034] The LC media according to the invention allow one or more of the following advantageous effects to be achieved:

[0035] - Very high clearing point,

[0036] - Advantageously high average elastic constant K avg , which is equal to (K1+K2+K3) / 3, which contributes to low scattering parameters,

[0037] - relatively low birefringence, which combined with a high average elastic constant contributes to high contrast,

[0038] - relatively low viscosity, which enables fast response times,

[0039] - low threshold voltage, which is useful for reducing driving voltage and realizing energy-saving displays,

[0040] - Make the LC panel production process time and cost effective and energy efficient.

[0041] When used in LC displays, the LC media according to the invention exhibit one or more of the following advantageous properties:

[0042] - Very high clearing point,

[0043] - High contrast,

[0044] -High transmittance,

[0045] - reduced rotational viscosity,

[0046] -Fast response time,

[0047] - Low threshold voltage, which is useful for realizing energy-saving displays.

[0048] In context, represents a trans-1,4-cyclohexylene ring, and It represents a 1,4-phenylene ring.

[0049] In the group In the case of phenylene, the single bond between two ring atoms can be connected to any free position of the benzene ring.

[0050] If the group R A1,A2,B1,B2 ,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 represents alkyl and / or alkoxy, which may be straight-chain or branched. It is preferably straight-chain, has 2, 3, 4, 5, 6 or 7 C atoms and correspondingly preferably represents ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy or heptyloxy, as well as methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy or tetradecyloxy.

[0051] If one of the abovementioned terminal groups represents an alkyl group in which one or more CH2 groups are 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 correspondingly preferably represents thiomethyl, thioethyl, thiopropyl, thiobutyl, thiopentyl, thiohexyl or thioheptyl.

[0052] Oxaalkyl preferably represents straight-chain 2-oxapropyl (=methoxymethyl), 2-oxabutyl (=ethoxymethyl) or 3-oxabutyl (=2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 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.

[0053] If one of the abovementioned terminal groups represents an alkoxy group or an oxaalkyl group, it may also contain one or more additional oxygen atoms, provided that the oxygen atoms are not directly bonded to one another.

[0054] If one of the abovementioned terminal groups represents an alkyl radical in which one CH2 group has been replaced by -CH=CH-, it may be straight-chain or branched. It is preferably straight-chain and has 2 to 10 C atoms. Accordingly, it represents, in particular, 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.

[0055] If one of the abovementioned terminal groups represents an alkyl or alkenyl group which is at least monosubstituted by halogen, the 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 may be in any desired position, but is preferably in the ω-position.

[0056] In another preferred embodiment, one or more of the above terminal groups, such as R A1,A2,B1,B2 ,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 is selected from the following groups

[0057]

[0058] -S 1 -F,-OS 1 -F,-O-S1-O-S2, where S 1 C 1-12 -alkylene or C 2-12 -Alkenylene and S 2 H, C 1-12 -alkyl or C 2-12 -alkenyl, and very preferably selected from the following groups

[0059]

[0060] -OCH2OCH3,

[0061] -O(CH2)2OCH3,-O(CH2)3OCH3,-O(CH2)4OCH3,-O(CH2)2F,-O(CH2)3F,-O(CH2)4F.

[0062] Halogen is preferably F or Cl, very preferably F.

[0063] Group-CR 0 =CR 00 -Preferably -CH=CH-.

[0064] -CO-, -C(=O)- and -C(O)- represent carbonyl groups, i.e.

[0065] Preferred substituents L are, for example, F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, -C(=O)N(R x )2, -C(=O)Y 1 、-C(=O)R x 、-N(R x ) 2, straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, each having 1 to 25 C atoms, wherein one or more H atoms may be optionally 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,

[0066] Where R xrepresents H, F, Cl, CN, or a straight-chain, branched or cyclic alkyl group having 1 to 25 C atoms, wherein one or more non-adjacent CH2 groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that the O- and / or S-atoms are not directly connected to each other, and wherein one or more H atoms are each optionally replaced by F, Cl, P- or P-Sp-, and Y 1 Represents halogen.

[0067] Particularly preferred substituents L are, for example, F, Cl, CN, NO2, CH3, C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5 and phenyl.

[0068] Preferably

[0069] wherein L has one of the meanings as stated above.

[0070] 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.

[0071] In a preferred embodiment, the LC media according to the invention comprise one or more compounds of the formula IA, preferably selected from the compounds of the formulae IA-a to IA-e:

[0072]

[0073] Among them, alkyl and alkyl * independently of one another represent alkyl having 1 to 7 C atoms, alkenyl and alkenyl * Independently of one another, they represent alkenyl having 2 to 7 C atoms, and cycloalkyl represents cycloalkyl having 3 to 12 C atoms, preferably cyclopropyl, cyclobutyl, cyclopentyl, cyclopropylalkyl, cyclobutylalkyl or cyclopentylalkyl.

[0074] Very preferred compounds of formulae IA-a to IA-e are selected from compounds of formulae IA-a-1 to IA-a-8, IA-b-1 to IA-b-3, IA-c-1 to IA-c-4, IA-d-1 to IA-d-7 and IA-e-1 to IA-e-8.

[0075]

[0076]

[0077]

[0078]

[0079]

[0080] wherein alkyl represents ethyl, n-propyl, n-butyl or n-pentyl, preferably n-propyl.

[0081] Preferred compounds of formula IA are IA-a and IA-b, and most preferred are compounds CWC-3-3, CWC-2-4 and CWC-3-V.

[0082] In a preferred embodiment, the LC media according to the invention comprise one or more compounds of the formula IB, preferably selected from the group consisting of the compounds of the formulae IB-1 to IB-14:

[0083] In another preferred embodiment, the LC medium comprises one or more compounds of the formula IB selected from the following formulae,

[0084]

[0085]

[0086]

[0087] Among them, alkyl and alkyl * Each independently represents a straight-chain or branched alkyl group having 1 to 6 C atoms, alkenyl represents a straight-chain or branched alkenyl group having 2 to 6 C atoms, and (O) represents an oxygen atom or a single bond, alkenyl preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-

[0088] (CH2)2CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0089] Particularly preferred LC media according to the invention comprise one or more compounds of the formula IB-1, IB-2, IB-9 and / or IB-14.

[0090] Very preferred compounds of formula IB are selected from the following subformulae of IB-1,

[0091]

[0092]

[0093]

[0094]

[0095] where v is 1, 2, 3, 4, 5, or 6.

[0096] Very preferred compounds of formula IB are selected from the following subformulas of IB-2,

[0097]

[0098]

[0099]

[0100]

[0101] where v is 1, 2, 3, 4, 5, or 6.

[0102] Highly preferred compounds of formula IB are selected from the following sub-formulas of IB-9,

[0103]

[0104]

[0105]

[0106]

[0107]

[0108] where v is 1, 2, 3, 4, 5, or 6.

[0109] In a preferred embodiment, the LC medium comprises one or more compounds of formula IB-9a

[0110]

[0111] Where R 21 , Y and q have the meanings given in Formula IB, and R 23 for wherein r is 0, 1, 2, 3, 4, 5 or 6, and s is 1, 2 or 3.

[0112] Preferred compounds of formula IB-9a are compounds IB-9a-1 to IB-9a-14:

[0113]

[0114]

[0115]

[0116] Highly preferred compounds of formula IB are selected from the following subformulas of IB-14,

[0117]

[0118]

[0119]

[0120]

[0121]

[0122] where v is 1, 2, 3, 4, 5, or 6.

[0123] Further preferred embodiments of the LC media according to the invention are listed below, including any combinations thereof:

[0124] Preferably, the LC medium comprises one or more compounds of the formula II selected from the group consisting of compounds of the formulae IIA, IIB, IIC, IID and IIE,

[0125]

[0126] Here, the individual radicals, identical or different on each occurrence and independently of one another, have the following meanings:

[0127] R 21 and R 22 denotes H, alkyl, alkoxy or alkenyl with up to 15 C atoms, which is unsubstituted or monosubstituted by F, Cl, CN or CF3, wherein in addition one or more CH2 groups of these radicals may be replaced by -O-, -S-, -C≡C-, -CF2O-, -OCF2-, -OC-O-, -O-CO- in such a way that the O- and / or S-atoms are not directly connected to one another.

[0128]

[0129] Instead,

[0130] L 1 To L 4 represents F, Cl, CF3 or CHF2,

[0131] Y represents H, F, Cl, CF3, CHF2 or CH3, preferably H or CH3, particularly preferably H,

[0132] Z 1 ,Z 2represents a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF-, -CH=CHCH2O,

[0133] p represents 0, 1, or 2, and

[0134] q represents 0 or 1.

[0135] Preferred compounds of formula IIA, IIB, IIC, IID and IIE are those wherein R 21 or R 22 Those representing alkyl or alkoxy groups having up to 15 C atoms and very preferably representing (O)C v H 2v+1 , wherein (O) is an oxygen atom or a single bond and v is 1, 2, 3, 4, 5 or 6.

[0136] Further preferred compounds of formula IIA, IIB, IIC, IID and IIE are those wherein R 21 or R 22 Those representing or containing cycloalkyl or cycloalkoxy groups, preferably selected from

[0137]

[0138] Where S 1 C 1-12 -alkylene or C 2-12 -Alkenylene and S 2 H, C 1-12 -alkyl or C 2-12 -alkenyl, and very preferably selected from

[0139]

[0140]

[0141] Further preferred compounds of formula IIA, IIB, IIC, IID and IIE are shown below.

[0142] In a preferred embodiment, the LC medium comprises one or more compounds of formula IIA selected from the following formulae:

[0143]

[0144]

[0145]

[0146]

[0147]

[0148]

[0149]

[0150]

[0151]

[0152]

[0153]

[0154] The parameter a represents 1 or 2, alkyl and alkyl * each independently of one another represents a straight-chain or branched alkyl group having 1 to 6 C atoms, alkenyl represents a straight-chain or branched alkenyl group having 2 to 6 C atoms, and (O) represents an oxygen atom or a single bond, alkenyl preferably representing CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0155] 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.

[0156] Preferably, the LC medium comprises one or more compounds of formula IIA-2 selected from the following subformulae:

[0157]

[0158] Alternatively, it is preferred that 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:

[0159]

[0160]

[0161] Further preferably, the LC medium comprises one or more compounds of formula IIA-10 selected from the following subformulae:

[0162]

[0163]

[0164] Alternatively, it is preferred that 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:

[0165]

[0166]

[0167] Further preferably, the LC medium comprises one or more compounds of formula IIA-16 selected from the following subformulae:

[0168]

[0169] Further preferably, the LC medium comprises one or more compounds of formula IIA-40 selected from the following subformulae:

[0170]

[0171]

[0172] Alternatively, it is preferred that 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:

[0173]

[0174] Further preferably, the LC medium comprises one or more compounds of formula IIA-42 selected from the following subformulae:

[0175]

[0176] Further preferably, the LC medium comprises one or more compounds of formula IIA-67 selected from the following subformulae:

[0177]

[0178]

[0179] Further preferably, the LC medium comprises one or more compounds of formula IIA-69 selected from the following subformulae:

[0180]

[0181]

[0182] Further preferably, the LC medium comprises one or more compounds of formula IIA-81 selected from the following subformulae:

[0183]

[0184] Preferred LC media additionally comprise one or more compounds of the formula IIA-Y

[0185]

[0186] Where R 21 and R 22 has one of the meanings given above in formula IIA, and L 1 and L 2 represents F or Cl identically or differently.

[0187] Preferred compounds of formula IIA-Y are selected from the following sub-formulas

[0188]

[0189]

[0190] Among them, Alkyl and Alkyl * Each independently of one another represents a straight-chain or branched alkyl radical having 1 to 6 C atoms, Alkoxy represents a straight-chain or branched alkoxy radical having 1 to 6 C atoms, Alkenyl and Alkenyl * Each independently represents a straight-chain or branched alkenyl group having 2 to 6 C atoms, and O represents an oxygen atom or a single bond. * Preferably it represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0191] Particularly preferred compounds of formula IIA-Y are selected from the following sub-formulae:

[0192]

[0193] Among them, Alkoxy and Alkoxy * has the meaning defined above and preferably represents methoxy, ethoxy, n-propoxy, n-butoxy or n-pentoxy.

[0194] In another preferred embodiment, the LC medium comprises one or more compounds of the formula IIB selected from the group consisting of formulae IIB-1 to IIB-26,

[0195]

[0196]

[0197]

[0198]

[0199] Among them, alkyl and alkyl * Each independently of one another represents a straight-chain or branched alkyl group having 1 to 6 C atoms, alkenyl represents a straight-chain or branched alkenyl group having 2 to 6 C atoms, and (O) represents an oxygen atom or a single bond, alkenyl preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0200] 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.

[0201] Preferably, the LC medium comprises one or more compounds of formula IIB-11 selected from the following subformulae:

[0202]

[0203] Alternatively, it is preferred that 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:

[0204]

[0205]

[0206] Preferably, the LC medium comprises one or more compounds of formula IIB-17 selected from the following subformulae:

[0207]

[0208]

[0209] In another preferred embodiment, the LC medium comprises one or more compounds of the formula IIC selected from the group consisting of formula IIC-1,

[0210]

[0211] Among them, alkyl and alkyl * Each independently of one another represents a straight-chain alkyl radical having 1 to 6 C atoms, which is preferably contained in an amount of 0.5 to 5% by weight, in particular 1 to 3% by weight.

[0212] In a preferred embodiment, the LC medium comprises one or more compounds of formula IID selected from the following formulae:

[0213]

[0214]

[0215]

[0216]

[0217]

[0218]

[0219]

[0220]

[0221]

[0222]

[0223]

[0224] The parameter a represents 1 or 2, alkyl and alkyl * Each independently of one another represents a straight-chain alkyl group having 1 to 6 C atoms, alkenyl represents a straight-chain alkenyl group having 2 to 6 C atoms, and (O) represents an oxygen atom or a single bond, alkenyl preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0225] Particularly preferred LC media according to the invention comprise one or more compounds selected from the group consisting of formulae IID-2, IID-8, IID-10, IID-16, IID-18, IID-37, IID-38, IID-39 and IID-40.

[0226] Preferably, the LC medium comprises one or more compounds of formula IID-2 selected from the following subformulae:

[0227]

[0228]

[0229] Preferably, the LC medium comprises one or more compounds of formula IID-10 selected from the following subformulae:

[0230]

[0231]

[0232] In another preferred embodiment, the LC medium comprises one or more compounds of formula IIE selected from the following formulae,

[0233]

[0234] Among them, alkyl and alkyl * Each independently of one another represents a straight-chain or branched alkyl radical having 1 to 6 C atoms.

[0235] Preferably, the LC medium comprises one or more compounds of formula IIE-2 selected from the following subformulae:

[0236]

[0237]

[0238] 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, II-18, IIA-40, IIA-41, IIA-42, IIA-43, IIA-67, IIA-69, IIA-81, IIB-2, IIB-10, IIB-16, IIC-1, IID-2, IID-8, IID-10, IID-16, IID-18, IID-37, IID-38, IID-39, IID-40 and IIE-2 or subformulae thereof.

[0239] The proportion of compounds of the formula IIA and / or IIB in the mixture as a whole is preferably at least 20% by weight.

[0240] Preferably, the LC medium further comprises one or more compounds of formula III,

[0241]

[0242] in

[0243] R 31 and R 32 each independently of one another represents H, alkyl or alkoxy having 1 to 15 C atoms, preferably 1 to 7 C atoms, wherein one or more -CH2- groups in these radicals may each independently of one another be affixed in such a way that the O atoms are not directly connected to one another -C≡C-, -CF2O-, -OCF2-, -CH=CH-, replaced by -O-, -CO-O- or -O-CO-, and one or more H atoms may be replaced by halogen,

[0244] A 3 at each occurrence, independently of one another, represents 1,4-phenylene, in which one or two CH groups may be replaced by N, or 1,4-cyclohexylene or 1,4-cyclohexenylene, 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,

[0245] n represents 0, 1 or 2,

[0246] Z 3 represents, independently of one another, at each occurrence -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -CH=CH-, -C≡C- or a single bond,

[0247] L 31 and L 32 each independently represents F, Cl, CF3 or CHF2, and

[0248] Y 1 , Y 2 Each independently of one another represents H, F, Cl, CF3, CHF2, CH3 or OCH3, preferably H, CH3 or OCH3, very preferably H.

[0249] Preferred compounds of formula III are compounds of formula III-1 to III-6:

[0250]

[0251] The radicals occurring therein have the same meanings as given above under formula III and are preferably

[0252] R 31 and R 32 each independently of one another represents an alkyl, alkenyl or alkoxy radical having up to 15 C atoms, preferably having 1 to 7 C atoms, more preferably one or two of them represent an alkoxy radical; or a cycloalkyl radical having 3 to 6 C atoms,

[0253] R 33 represents an alkyl or alkenyl group having up to 7 C atoms, or a group Cy-C n H 2n+1 -,

[0254] m and n, identically or differently, are 0, 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, very preferably 1,

[0255] 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,

[0256] (O) represents O or a single bond,

[0257] L 31 and L 32 Each independently represents F or Cl, preferably both represent F, and

[0258] Y 3 represents H, F, Cl, CF3, CHF2, CH3 or OCH3, preferably H or CH3.

[0259] 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,

[0260]

[0261]

[0262]

[0263] Among them, alkyl and alkyl * each independently of one another represents a straight-chain alkyl radical having 1 to 6 C atoms, alkenyl and alkenyl * each independently of one another represents a straight-chain alkenyl group having 2 to 6 C atoms, alkoxy and alkoxy * each independently represents 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.

[0264] Very preferred compounds of formula III-1-1 are selected from the following sub-formulae,

[0265]

[0266] Very preferred compounds of formula III-1-11 are selected from the following sub-formulae,

[0267]

[0268]

[0269] Very preferred compounds of formula III-2 are the following,

[0270]

[0271]

[0272] Here, alkoxy is a straight-chain alkoxy group having 1 to 6 C atoms, preferably ethoxy, propoxy, butoxy or pentoxy, very preferably ethoxy or propoxy, and alkenyl is a straight-chain alkenyl group having 2 to 6 C atoms.

[0273] Very preferred compounds of formula III-6 are selected from the following formula,

[0274]

[0275]

[0276]

[0277]

[0278] Where R 32 represents alkyl having 1 to 7 C atoms, preferably ethyl, n-propyl or n-butyl, or alternatively represents cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl, or alternatively represents -(CH2) n F, wherein n is 2, 3, 4 or 5, preferably C2H4F.

[0279] 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.

[0280] Preferably, the LC medium further comprises one or more compounds of formula IIIA:

[0281]

[0282] 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 for formula III.

[0283] In a preferred embodiment of the present invention, the LC medium comprises one or more compounds of the formula IIIA-1:

[0284]

[0285] The radicals occurring therein have the same meanings as given above under formula IIIA and are preferably

[0286] 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 two of them represents an alkoxy group, or a cycloalkyl group having 3 to 6 C atoms, and

[0287] L 31 and L 32 Each independently represents F or Cl, preferably both represent F.

[0288] In another preferred embodiment, the LC medium comprises one or more compounds of the formula IIIA-1 selected from the compounds of the formulae IIIA-1-1 to IIIA-1-20, preferably the compounds of the formulae IIIA-1-8 and IIIA-1-18,

[0289]

[0290]

[0291]

[0292] Among them, alkyl and alkyl * each independently of one another represents a straight-chain alkyl radical having 1 to 6 C atoms or a cycloalkyl radical having 3 to 6 C atoms, alkenyl and alkenyl * each independently of one another represents a straight-chain alkenyl group having 2 to 6 C atoms, alkoxy and alkoxy * each independently represents 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.

[0293] Preferably, the LC medium comprises one or more compounds of formula IIIA-1-8 selected from the following subformulae:

[0294]

[0295] Preferably, the LC medium comprises one or more compounds of formula IIIA-1-18 selected from the following subformulae:

[0296]

[0297] In another preferred embodiment of the present invention, the LC medium comprises one or more compounds of the formula IIIA-2

[0298]

[0299] Where L 31 and L 32 have the same meanings as given under formula IIIA, (O) represents O or a single bond,

[0300] R 33 represents an alkyl or alkenyl group having up to 7 C atoms, or a group Cy-C n H 2n+1 -,

[0301] m and n, identically or differently, are 0, 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, very preferably 1, and

[0302] 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.

[0303] Alternatively or in addition to the compound of formula III, preferably in addition to the compound of formula III, a compound of formula IIIA-2 is also comprised in the LC medium.

[0304] A highly preferred compound of formula IIIA-2 is as follows,

[0305]

[0306] Here, alkoxy represents a straight-chain alkoxy group having 1 to 6 C atoms.

[0307] In another preferred embodiment, the LC medium comprises one or more compounds of the formula IIIA selected from the group consisting of compounds of the formulae IIIA-3 to IIIA-5,

[0308]

[0309]

[0310] The radicals occurring therein have the same meanings as given under formula III, and R 31 Preferably represents a straight-chain alkyl group or a cycloalkyl group, and R 32 Preferably it denotes alkoxy radicals having in each case 1 to 7 C atoms.

[0311] In a preferred embodiment of the present invention, the LC medium comprises one or more compounds of the formula IIIA-6:

[0312]

[0313] The radicals occurring therein have the same meanings as given under formula III, and preferably 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 two of them represent an alkoxy group.

[0314] Very preferred compounds of formula IIIA-6 are selected from the following formulae,

[0315]

[0316]

[0317] Where R 32 represents alkyl having 1 to 7 C atoms, preferably ethyl, n-propyl or n-butyl, or alternatively represents cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl, or alternatively represents -(CH2) n F, wherein n is 2, 3, 4 or 5, preferably C2H4F.

[0318] 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.

[0319] In a preferred embodiment, the LC medium comprises one or more compounds of formula IV,

[0320]

[0321] in

[0322] R 41 represents an unsubstituted alkyl radical having 1 to 7 C atoms, in which one or more CH2 groups may be

[0323]

[0324] substituted, or unsubstituted alkenyl having 2 to 7 C atoms, preferably n-alkyl, particularly preferably having 2, 3, 4 or 5 C atoms, and

[0325] R 42represents unsubstituted alkyl having 1-7 C atoms, or cycloalkyl having 3-6 C atoms, or unsubstituted alkoxy having 1-6 C atoms, preferably having 2-5 C atoms, unsubstituted alkenyl having 2-7 C atoms, preferably having 2, 3 or 4 C atoms, more preferably vinyl or 1-propenyl and in particular vinyl.

[0326] The compound of formula IV is preferably selected from formulae IV-1 to IV-4,

[0327]

[0328] in

[0329] alkyl and alkyl * independently of one another represent an alkyl group having 1 to 7 C atoms, preferably having 2 to 5 C atoms,

[0330] Alkenyl is an alkenyl radical having 2 to 5 C atoms, preferably 2 to 4 C atoms, particularly preferably 2 C atoms,

[0331] alkenyl * represents 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

[0332] Alkoxy is an alkoxy group having 1 to 5 C atoms, preferably having 2 to 4 C atoms.

[0333] Preferably, the LC medium comprises one or more compounds selected from the group consisting of compounds of formulae IV-1-1 to IV-1-14

[0334]

[0335]

[0336] wherein alkyl represents methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or n-pentyl.

[0337] 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

[0338]

[0339] 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

[0340]

[0341]

[0342] 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 of 15 to 70%, preferably 25 to 55%, very preferably 30 to 50%. CC-3-V is preferably used in a concentration of 5 to 60%, in particular 10 to 55%.

[0343] 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:

[0344]

[0345]

[0346] Very preferably, the LC media according to the invention comprise a compound of the formula IV-4, in particular a compound selected from the following formulae

[0347]

[0348]

[0349] In another preferred embodiment, the LC medium comprises one or more compounds of formula IV-4 and its subformulae, wherein "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.

[0350] 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%.

[0351] The LC media according to the invention preferably additionally comprise one or more compounds of the formula IVa,

[0352]

[0353] in

[0354] R 41 and R 42 each independently of one another represents straight-chain alkyl, alkoxy, alkenyl, alkoxyalkyl or alkoxy radical having up to 12 C atoms, or cycloalkyl radical having 3 to 6 C atoms,

[0355] express

[0356] Z 4 It represents a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -C4H8- or -CF=CF-.

[0357] Preferred compounds of formula IVa are shown below:

[0358]

[0359] Among them, alkyl and alkyl * Each independently of one another represents a straight-chain alkyl radical having 1 to 6 C atoms.

[0360] The LC media according to the invention preferably comprise at least one compound of the formula IVa-1 and / or formula IVa-2.

[0361] The proportion of the compound of the formula IVa in the mixture as a whole is preferably at least 5% by weight.

[0362] Preferably, the LC medium comprises one or more compounds of the formulae IVb-1 to IVb-3

[0363]

[0364] in

[0365] alkyl and alkyl * Each independently represents a straight-chain alkyl group having 1 to 6 C atoms, or a cycloalkyl group having 3 to 6 C atoms, preferably alkyl represents a methyl group, and

[0366] alkenyl and alkenyl * each independently of one another represents a straight-chain alkenyl group having 2 to 6 C atoms.

[0367] 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.

[0368] Among the compounds of formulae IVa-1 to IVa-4, the compound of formula IVa-2 is particularly preferred.

[0369] Among the compounds of formulae IVb-1 to IVb-3, the compound of formula IVb-2 is particularly preferred.

[0370] Particularly preferred compounds of formula IV-1 to IV-3 are selected from the following

[0371]

[0372] Among them, alkyl * represents an alkyl radical having 1 to 6 C atoms and preferably represents n-propyl.

[0373] The LC media according to the invention particularly preferably comprise one or more compounds of the formulae IVb-1-1, IVb-2-3 and / or IVb-2-4.

[0374] In another preferred embodiment, the LC media according to the invention comprise one or more compounds of the formula V

[0375]

[0376] in

[0377] R 51 and R 52 independently of one another denotes H, an alkyl, alkoxy or alkenyl radical having up to 15 C atoms, which is unsubstituted, monosubstituted by F, Cl, CN or CF3 or at least monosubstituted by halogen, wherein one or more CH2 groups in these radicals may be replaced by -O-, -S-, -C≡C-, -CF2O-, -OCF2-, -OC-O-, -O-CO- in such a way that the O atoms are not connected to one another.

[0378]

[0379] , preferably alkyl with 1 to 7 C atoms, preferably n-alkyl, particularly preferably n-alkyl with 1 to 5 C atoms, alkoxy with 1 to 6 C atoms, preferably n-alkoxy, particularly preferably n-alkoxy with 2 to 5 C atoms, alkoxyalkyl, alkenyl or alkenyloxy with 2 to 7 C atoms, preferably with 2 to 4 C atoms, preferably alkenyloxy,

[0380] Same or different

[0381]

[0382] in

[0383] Preferred representation

[0384] Z 51 ,Z 52 Each independently represents -CH2-CH2-, -CH2-O-, -CH=CH-, -C≡C-, -COO- or a single bond, preferably -CH2-CH2-, -CH2-O- or a single bond and particularly preferably a single bond, and n is 1 or 2.

[0385] wherein one or more compounds of formula V are different from compounds of formula I.

[0386] The compound of formula V is preferably selected from the compounds of formulae V-1 to V-17:

[0387]

[0388]

[0389] Where R 51 and R 52 Has the meaning stated above.

[0390] R 51 and R 52 Preferably each independently of one another represents a straight-chain alkyl or alkenyl group.

[0391] Preferred LC media comprise one or more compounds of the formula V-1, V-3, V-4, V-6, V-10, V-11, V-12, V-14, V-15 and / or V-16.

[0392] The LC media according to the invention very particularly preferably comprise compounds of the formula V-10 and / or IV-1, in particular in an amount of 5 to 30%.

[0393] Preferred compounds of formula V-10 are shown below:

[0394]

[0395] The LC medium according to the invention particularly preferably comprises a combination of a tricyclic compound of the formula V-10a and / or V-10b with one or more bicyclic compounds of the formula IV-1. The total proportion of the combination of the compounds of the formula V-10a and / or V-10b with one or more compounds selected from the dicyclohexyl compounds of the formula IV-1 is 5 to 40%, very particularly preferably 15 to 35%.

[0396] Particularly preferred LC media comprise compounds V-10a and / or IV-1-1

[0397]

[0398] The compounds V-10a 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 entire mixture.

[0399] Preferred LC media comprise at least one compound selected from the group consisting of

[0400]

[0401]

[0402] Where R 41 , R 42 , R 51 and R 52 Preferably, in compounds V-6, I and IV, R 41 and R 51 represents an alkyl or alkenyl group having 1 to 6 C atoms 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-14, R 51 represents an alkyl or alkenyl group having 1 to 6 C atoms or 2 to 6 carbon atoms and R 52 represents an alkyl group having 1 to 6 C atoms.

[0403] 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,

[0404]

[0405]

[0406]

[0407]

[0408] in

[0409] R 61 represents a straight-chain alkyl or alkoxy group having 1 to 6 C atoms, or a cyclic alkyl group having 3 to 6 C atoms, (O) represents -O- or a single bond, X represents F, Cl, OCF3 or OCHF2, 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.

[0410] R 61 Preferably, it represents methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy or pentyloxy.

[0411] X preferably represents F or OCH3, very preferably represents F.

[0412] The LC media according to the invention preferably comprise 2 to 30% by weight, in particular 5 to 20% by weight, of terphenyls of the formulae VI-1 to VI-24.

[0413] Particularly preferred are compounds of the formulae VI-1, VI-3, VI-19, VI-20 and VI-21, wherein X represents F. In these compounds, R 61Preferably represents alkyl, and also alkoxy, each having 1 to 5 C atoms. In the compound of formula VI-19, R 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.

[0414] The terphenyls of the formulae VI-1 to VI-24 are preferably used in the LC media according to the invention in the case where the Δn value of the mixture is ≥ 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.

[0415] 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

[0416]

[0417]

[0418] in

[0419] R 71 Each independently has the formula IIA where R 21 One of the meanings of the indication, and

[0420] w and x each independently represent 1 to 6.

[0421] Particular preference is given to LC media which comprise at least one compound of the formula VII-9.

[0422] LC medium comprising one or more substances containing tetrahydronaphthyl or naphthyl units, for example compounds of formulae N-1 to N-5,

[0423]

[0424] Where R N1 and R N2 Each independently has the above for R 21 The above meanings preferably denote straight-chain alkyl, straight-chain alkoxy or straight-chain alkenyl, and

[0425] Z N1 and Z N2Each independently represents -C2H4-, -CH=CH-, -(CH2)4-, -(CH2)3O-, -O(CH2)3-, -CH=CHCH2CH2-, -CH2CH2CH=CH-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF-, -CF=CH-, -CH=CF-, -CF2O-, -OCF2-, -CH2- or a single bond.

[0426] LC medium comprising one or more compounds selected from the group consisting of difluorodibenzochroman of formula BC, chroman of formula CR, and fluorophenanthrene compounds of formulae PH-1 and PH-2,

[0427]

[0428] in

[0429] R 81 and R 82 Each independently has R 21 , R 81 and R 82 , preferably independently of one another, alkyl or alkoxy having 1 to 6 C atoms, or cycloalkyl having 3 to 6 C atoms,

[0430] c is 0, 1, or 2,

[0431] Y 1 , Y 2 , Y 3 , Y 4 Each independently of one another represents H, F, Cl, CF3, CHF2, CH3 or OCH3.

[0432] The LC media according to the invention preferably comprise the compounds of the formulae 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.

[0433] Particularly preferred compounds of formula BC and CR are compounds BC-1 to BC-7 and CR-1 to CR-5,

[0434]

[0435]

[0436]

[0437] in

[0438] alkyl and alkyl * each independently of one another represents a straight-chain alkyl group having 1 to 6 C atoms, or a cycloalkyl group having 3 to 6 C atoms, and

[0439] alkenyl and alkenyl * each independently of one another represents a straight-chain alkenyl group having 2 to 6 C atoms.

[0440] A particularly preferred compound of formula BC is compound B(A)-2O-O2,

[0441]

[0442] Particularly preferred compounds of formula PH-1 are compounds B(P)-2O-O3 and B(P)-2O-O4,

[0443]

[0444] The LC medium comprises one or more indane compounds of the formula In,

[0445]

[0446] in

[0447] R 91 ,R 92 ,

[0448] R 93 each independently of one another represents a straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl radical having 1 to 6 C atoms, or a cycloalkyl radical having 3 to 6 C atoms,

[0449] R 92 and R 93 It may also represent halogen, preferably F,

[0450] express

[0451]

[0452] i represents 0, 1 or 2.

[0453] Preferred compounds of formula In are compounds of formula In-1 to In-16 described below:

[0454]

[0455]

[0456]

[0457] Particularly preferred are compounds of the formulae In-1, In-2, In-3 and In-4.

[0458] The compounds of the formula In and of 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 5 to 30% by weight and very particularly preferably 5 to 25% by weight.

[0459] The LC medium comprises one or more compounds of formulae L-1 to L-8,

[0460]

[0461]

[0462] in

[0463] R L1 and R L2 Each independently has the above R 21 The parameter s represents 1 or 2.

[0464] 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.

[0465] The LC medium comprises one or more quaternary compounds selected from the following formulae

[0466]

[0467] in

[0468] 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,

[0469] X Q is F, Cl, a haloalkyl or alkoxy group having 1 to 6 C atoms, or a haloalkenyl or alkenyloxy group having 2 to 6 C atoms,

[0470] L Q1 -L Q6 Each independently is H or F, wherein L Q1 -L Q6 At least one of them is F.

[0471] Preferred compounds of formula Q are those wherein R Q Those representing straight-chain alkyl radicals having 2 to 6 C atoms, very preferably ethyl, n-propyl or n-butyl.

[0472] Preferred compounds of formula Q are those wherein L Q3 and L Q4 Those wherein L is F. Further preferred compounds of formula Q are those wherein LQ3 , L Q4 and L Q1 and L Q2 Those in which one or both are F.

[0473] Preferred compounds of formula Q are those wherein X Q Those representing F or OCF3, F being very preferred.

[0474] The compound of formula Q is preferably selected from the following sub-formula

[0475]

[0476] Where R Q has one of the meanings of the formula Q or one of the preferred meanings given above or below, and is preferably ethyl, n-propyl or n-butyl.

[0477] Particularly preferred are compounds of formula Q1, especially those wherein R Q Those which are n-propyl.

[0478] Preferably, the proportion of compounds of the formula Q in the LC medium is >0 to ≤5 wt %, very preferably 0.05-2 wt %, more preferably 0.1-1 wt %, most preferably 0.1-0.8 wt %.

[0479] Preferably the LC medium contains 1 to 5, preferably 1 or 2, compounds of formula Q.

[0480] Adding the quaterphenyl compound of formula Q to the LC mixture of a polymerizable LC medium can reduce ODF inhomogeneities while maintaining high UV absorption, achieve rapid and complete polymerization, produce strong and fast tilt, and improve the UV stability of the LC medium.

[0481] Furthermore, adding the compound of formula Q with positive dielectric anisotropy to the LC medium with negative dielectric anisotropy can better control the dielectric constant ε || and ε ⊥ values, especially high dielectric constant ε || value and keep the dielectric anisotropy Δε constant, thereby reducing the kickback voltage and reducing image sticking.

[0482] The LC media according to the invention preferably comprise

[0483] one or more compounds of the formula IA or its subformulae, preferably compounds of the formula IA-a, preferably in a proportion of 0.5 to 30% by weight, very preferably 1 to 25% by weight, most preferably 2 to 20% by weight;

[0484] and / or

[0485] one or more compounds of the formula IB or its subformulae, preferably compounds of the formula IB-2 and / or IB-9, preferably in a proportion of 5 to 50% by weight, very preferably 8 to 45% by weight, most preferably 10 to 40% by weight;

[0486] and / or

[0487] - one or more compounds of formula II or its subformulae, preferably compounds of formula IIA and / or IIB, preferably in a total concentration in the range of 3-30%, more preferably 5-25%, particularly preferably 7-20%;

[0488] and / or

[0489] - one or more compounds of formula III or its subformulae, preferably compounds of formula III-1 and / or III-6, preferably in a total concentration in the range of 0.1-30%, more preferably 1-20%, very preferably 1-18%;

[0490] and / or

[0491] - one or more compounds of formula BC or its subformulae, preferably in a total concentration in the range of 0.1-30%, more preferably 1-20%, very preferably 1-18%;

[0492] and / or

[0493] - one or more compounds of formula PH-1 or its subformulae, preferably in a total concentration in the range of 0.1-30%, more preferably 1-20%, very preferably 1-18%;

[0494] and / or

[0495] - one or more compounds of formula IV or its subformulae, preferably compounds of formula IV-1, IV-3 and IVa-2, preferably in a total concentration in the range of 25-60%, more preferably 27-55%, particularly preferably 30-50%;

[0496] and / or

[0497] - one or more compounds of formula V or its subformulae, preferably compounds of formula V-10, preferably in a total concentration in the range of 0.1-30%, more preferably 0.25-25%, particularly preferably 0.5-20%;

[0498] Further preferred embodiments are listed below, wherein the acronyms used are explained in Table B, wherein n and m are each independently an integer from 1 to 7:

[0499] - one or more compounds CWC-nm, and / or CWC-n-Vm, in particular CWC-3-3, CWC-2-4 and / or CWC-3-V, preferably in a total concentration in the range of 0.5-30%, preferably 1-25%, very preferably 2-20%, most preferably 2-20%, based on the entire mixture;

[0500] and / or

[0501] - one or more compounds CLY-n-Om and / or CLOY-n-Om, in particular CLY-3-O2, CLY-3-O3, CLY-4-O2, CLY-5-O2 and / or CLOY-3-O2, preferably in a total concentration in the range of 5-50%, more preferably 8-45%, most preferably 10-40%, based on the entire mixture;

[0502] and / or

[0503] - one or more compounds Y-nO-Om, CY-n-Om, CPY-n-Om, CCY-n-Om, CCY-Vn-Om and / or CAIY-n-Om, in particular Y-4O-O4, CY-3-O2, CPY-3-O2, CCY-3-O2, CCY-5-O2 and / or CAIY-3-O2, preferably in a total concentration in the range of 3 to 30%, more preferably 5 to 25%, particularly preferably 7 to 20%, based on the entire mixture;

[0504] and / or

[0505] - 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 in the range of 0.1-30%, more preferably 1-20%, very preferably 1-18%, based on the entire mixture;

[0506] and / or

[0507] - 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 in the range of 0.1-30%, more preferably 1-20%, very preferably 1-18%, based on the entire mixture;

[0508] and / or

[0509] - one or more compounds B(A)-nO-Om, in particular B(A)-2O-O2, preferably in a total concentration in the range of 0.1-30%, more preferably 1-20%, very preferably 1-18%, based on the entire mixture;

[0510] and / or

[0511] - one or more compounds CC-nm, CC-n-Om, CC-nV, CC-n-Vm and / or CP-n-Om, preferably CC-3-4, CC-3-5, CC-3-O3, CC-3-V, CC-3-V1, CC-4-V1 and / or CP-3-O2, preferably in a total concentration in the range of 25 to 60%, more preferably 27 to 55%, particularly preferably 30 to 50%, based on the entire mixture;

[0512] and / or

[0513] - 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 in the range of 5% to 30%, preferably 10% to 20%, based on the entire mixture;

[0514] and / or

[0515] - 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 in the range of 5% to 40%, preferably 10% to 30%, based on the entire mixture;

[0516] and / or

[0517] - 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 entire mixture;

[0518] and / or

[0519] - 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 5-15%, based on the entire mixture;

[0520] and / or

[0521] 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 5-20%, more preferably 10-15%, based on the entire mixture,

[0522] and / or

[0523] one or more compounds CCP-nm and / or CCP-Vn-m and / or CCP-nm, preferably selected from CCP-3-1, CCP-V-1, CCP-V2-1 and CPP-3-2, preferably in a total concentration of 0.5-35%, preferably 1-25%, based on the entire mixture,

[0524] and / or

[0525] one or more compounds CCZC-nm, in particular CCZC-3-3, preferably in a total concentration of 1-15%, preferably 2-10%, based on the entire mixture,

[0526] and / or

[0527] 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 entire mixture,

[0528] and / or

[0529] - one or more compounds selected from PYP-nm, PGIY-n-Om and PGP-n-2V, preferably in a total concentration of 2-20%, more preferably 2%-15%, most preferably 2-10%, based on the entire mixture,

[0530] and / or

[0531] 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 entire mixture,

[0532] and / or

[0533] - the compound PPGU-3-F, preferably in a concentration of 0.1% to 3%, based on the entire mixture.

[0534] It is advantageous for the liquid-crystalline media according to the invention to preferably have a nematic phase at ≤-20° C. to ≥70° C., particularly preferably ≤-30° C. to ≥80° C. and very particularly preferably ≤-40° C. to ≥90° C.

[0535] The LC media according to the invention have a clearing temperature of 70°C or more, preferably 85°C or more, for example 85°C to 125°C.

[0536] The expression "having a nematic phase" here means on the one hand that at low temperatures no smectic phase and no crystallization is observed at the corresponding temperature and on the other hand that the nematic phase does not become clear on heating. The low-temperature investigations are carried out in a flow viscometer at the corresponding temperature and are checked by storage for at least 100 hours in test cells with a layer thickness corresponding to the electro-optical use. If the storage stability in corresponding test cells at a temperature of -20°C 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 elevated temperatures, the clearing point is measured in a capillary by conventional methods.

[0537] The liquid crystal mixture preferably has a nematic phase range of at least 60 K and a maximum of 30 mm at 20° C. 2 ·s -1 The flow viscosity ν 20 .

[0538] The mixture is nematic at a temperature of -20°C or below, preferably at -30°C or below, very preferably at -40°C or below.

[0539] The birefringence Δn values ​​in the liquid crystal mixture are generally 0.07-0.16, preferably 0.08-0.15, very preferably 0.09-0.14. In a preferred embodiment of the invention, the birefringence of the LC medium is in the range of 0.075-0.110, preferably 0.077-0.108, in particular 0.080-0.105.

[0540] 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.

[0541] The rotational viscosity γ1 at 20° C. is preferably ≤245 mPa·s, in particular ≤240 mPa·s. In a preferred embodiment, the rotational viscosity γ1 at 20° C. is ≤235 mPa·s, in particular ≤230 mPa·s.

[0542] The liquid-crystal media according to the invention have relatively low threshold voltages (V0). They are preferably from 1.7 V to 3.0 V, particularly preferably ≤2.7 V and very particularly preferably ≤2.6 V.

[0543] For the present invention, unless explicitly stated otherwise, the term "threshold voltage" relates to the capacitive threshold (V0), also called Freedericks threshold.

[0544] Furthermore, the liquid-crystal media according to the invention have high voltage holding ratio values ​​in liquid-crystal cells.

[0545] Typically, LC media having a low addressing voltage or threshold voltage show lower voltage holding ratios than those LC media having a higher addressing voltage or threshold voltage, and vice versa.

[0546] For the purposes of the present invention, the term "dielectrically positive compounds" refers to compounds with Δε>1.5, the term "dielectrically neutral compounds" refers to those with -1.5≤Δε≤1.5 and the term "dielectrically negative compounds" refers to those with Δε<-1.5. The dielectric anisotropy of the compounds is determined here by dissolving 10% of the compound in a liquid crystal host in at least one test cell, the test cell having in each case a layer thickness of 20 μm and having a homeotropic and planar surface alignment at 1 kHz. The measuring voltage is generally between 0.5 V and 1.0 V, but is always below the capacitance threshold of the respective liquid crystal mixture under investigation.

[0547] All temperature values ​​described in the present invention are in ° C.

[0548] The LC media according to the invention are suitable for all FFS (fringe field switching) and UB-FFS (ultra-bright 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 stabilized VA) and PS-VA (polymer stabilized VA). Furthermore, they are also suitable for IPS (in-plane switching) applications with negative Δε.

[0549] 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.

[0550] Component A has a significant negative dielectric anisotropy and makes the dielectric anisotropy of the nematic phase ≤-0.5.

[0551] The proportion of component A is preferably 45-100%, in particular 60-85%.

[0552] For component A, preference is given to selecting one or more individual compounds with a Δε value of ≤−1.5. The smaller the proportion of A in the overall mixture, the more negative this value will necessarily be.

[0553] Component B is a dielectrically neutral compound with -1.5≤Δε≤1.5. In addition, component B has significant nematogeneity and a flow viscosity of not more than 30 mm at 20°C. 2 ·s -1 , preferably no more than 25mm 2 ·s -1 .

[0554] A wide variety of suitable materials are known to those skilled in the art from the literature.

[0555] Particularly preferred individual compounds in component B are extremely low viscosity nematic liquid crystals, the flow viscosity of which at 20° C. is not greater than 18 mm 2 ·s -1 , preferably no more than 12mm 2 ·s -1 .

[0556] Component B is monotropically or enantiotropically nematic, has no smectic phase, and is capable of preventing the occurrence of a smectic phase in the LC medium at 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 contrasted by suppressing the extent to which the smectic phase is reached.

[0557] The mixture may also optionally 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 entire mixture.

[0558] Besides the compounds of the formulae IA and IB, and the compounds of the formulae III and the compounds of the formulae IIA, IIB and / or IID, further components may also be present, for example in an amount of up to 45%, but preferably up to 35%, in particular up to 10%, of the entire mixture.

[0559] The further components are preferably selected from nematic or nematogenic substances, in particular from the known substances of the class of azobenzene, benzylidene aniline, biphenyl, terphenyl, phenyl or cyclohexyl benzoate, phenyl or cyclohexyl cyclohexanecarboxylate, phenylcyclohexane, cyclohexylbiphenyl, cyclohexylcyclohexane, cyclohexylnaphthalene, 1,4-dicyclohexylbiphenyl or cyclohexylpyrimidine, phenyldioxane or cyclohexyldioxane, optionally halogenated stilbenes, benzylphenyl ethers, tolans and substituted cinnamic esters.

[0560] The most important compounds suitable as constituents of this type of liquid-crystalline phase can be characterized by the formula R R R1 -LGER R2 R

[0561] wherein L and E each designate a carbocyclic or heterocyclic ring system from the group formed by 1,4-disubstituted benzene and cyclohexane rings, 4,4′-disubstituted biphenyl, phenylcyclohexane and cyclohexylcyclohexane systems, 2,5-disubstituted pyrimidine and 1,3-dioxane rings, 2,6-disubstituted naphthalene, dihydronaphthalene and tetrahydronaphthalene, quinazoline and tetrahydroquinazoline,

[0562] G represents -CH=CH- -N(O)=N-

[0563] -CH=CQ- -CH=N(O)-

[0564] -C≡C- -CH2-CH2-

[0565] -CO-O- -CH2-O-

[0566] -CO-S- -CH2-S-

[0567] -CH=N- -COO-Phe-COO-

[0568] -CF2O- -CF=CF-

[0569] -OCF2- -OCH2-

[0570] -(CH2)4- -(CH2)3O-

[0571] or a CC single bond, Q represents halogen, preferably chlorine or -CN, and R R1 and R R2 Each refers to an alkyl, alkenyl, alkoxy, alkoxyalkyl or alkoxycarbonyloxy group having up to 18, preferably up to 8, carbon atoms, or one of these groups alternatively represents CN, NC, NO2, NCS, CF3, SF5, OCF3, F, Cl or Br.

[0572] In most of these compounds, R R1 and R R2 Different from each other, one of these groups is usually an alkyl or alkoxy group. Other variations of the proposed substituents are also common. Many such substances or mixtures thereof are also commercially available. All these substances can be prepared by methods known from the literature.

[0573] It goes without saying for 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 are replaced by corresponding isotopes.

[0574] The LC medium preferably has a nematic LC phase.

[0575] In a preferred embodiment, the LC medium comprises 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 dopant is preferably selected from the compounds in Table C below, very preferably selected from R- or S-1011, R- or S-2011, R- or S-3011, R- or S-4011 and R- or S-5011.

[0576] In another preferred embodiment, the LC medium comprises the racemate of one or more chiral dopants, which are preferably selected from the chiral dopants mentioned in the previous paragraph.

[0577] In a further preferred embodiment of the present invention, the LC medium comprises one or more further stabilizers.

[0578] Preferred stabilizers are selected from compounds of formula H

[0579]

[0580] in

[0581] Ar represents an aromatic or heteroaromatic group having 4 to 40 C atoms, preferably 6 to 30 C atoms;

[0582] Sp represents a spacer group;

[0583] R S represents H, alkyl having 1 to 12 C atoms or alkenyl having 2 to 12 C atoms;

[0584] Z S Indicates -O-, -C(O)O-, -(CH2) z -or-(CH2) z O- or single bond;

[0585] HA means

[0586] R H Indicates H, O, CH3, OH or OR S , preferably H or O;

[0587] R S1 , R S2 , R S3 and R S4 represent, identically or differently, alkyl having 1 to 6 C atoms, preferably having 1 to 3 C atoms, very preferably CH3;

[0588] G stands for H or R S or group Z S -HA;

[0589] z is an integer from 1 to 6; and

[0590] q is 3 or 4.

[0591] Compounds of formula H are described in EP3354710A1 and EP3354709A1.

[0592] Preferred compounds of formula H are selected from formula H-1, H-2 and H-3:

[0593]

[0594] Where R H has the meaning given above, preferably represents H or O . , n is an integer from 0 to 12, preferably 5, 6, 7, 8 or 9, very preferably 7, Sp represents a spacer group, preferably an alkylene group having 1 to 12 C atoms, in which one or more non-adjacent -CH2- groups can be replaced by -O-.

[0595] Preferred compounds of formula H-1 are those of formula H-1-1:

[0596]

[0597] Where R H has the meaning given above and preferably represents H or O · , and n is an integer from 0 to 12, preferably 5, 6, 7, 8 or 9, very preferably 7.

[0598] Very preferred compounds of formula H-1-1 are those of formula H-1-1-1:

[0599]

[0600] Preferred compounds of formula H-2 are those of formula H-2-1:

[0601]

[0602] Where R H has the meaning given above and preferably represents H or O · , and n2 is identically or differently, preferably identically, an integer from 1 to 12 at each occurrence, preferably 2, 3, 4, 5 or 6, very preferably 3, and R S Identically or differently on each occurrence, preferably identically, denotes alkyl having 1 to 6 C atoms, preferably n-butyl.

[0603] Very preferred compounds of formula H-2-1 are those of formula H-2-1-1:

[0604]

[0605] Preferred compounds of formula H-3 are selected from formula H-3-1:

[0606]

[0607] Where Sp and R H has the meaning given above, and R H Preferably represents H or O · , and n is an integer from 0 to 12, preferably 5, 6, 7, 8 or 9, very preferably 7.

[0608] Further preferred stabilizers are selected from the group consisting of formulas ST-1 to ST-18:

[0609]

[0610]

[0611]

[0612]

[0613] in

[0614] R ST represents H, alkyl or alkoxy with 1 to 15 C atoms, wherein, in addition, one or more CH2 groups may each independently of one another be replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-,

[0615]

[0616] -O-, -CO-O-, -O-CO-, and wherein, in addition, one or more H atoms may be replaced by halogen,

[0617] To express the same or different meaning on each occurrence

[0618]

[0619] Z ST Each independently represents -CO-O-, -O-CO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -(CH2)4-, -CH=CH-, -CH2O-, -C2F4-, -CH2CF2-, -CF2CH2-, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C- or a single bond,

[0620] L 1 and L 2each independently represents F, Cl, CH3, CF3 or CHF2,

[0621] p represents 0, 1 or 2,

[0622] q represents 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0623] Preferred compounds of formula ST are those selected from formula ST-3, in particular:

[0624]

[0625] Where n=1, 2, 3, 4, 5, 6 or 7, preferably n=3

[0626]

[0627] Where n=1, 2, 3, 4, 5, 6 or 7, preferably n=3

[0628]

[0629] wherein n=1, 2, 3, 4, 5, 6 or 7, preferably n=1 or 7

[0630]

[0631] Where q=8.

[0632]

[0633]

[0634] In the compounds of formula ST-2a, n preferably represents 7.

[0635] Very preferred stabilizers are selected from the group consisting of 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:

[0636]

[0637]

[0638]

[0639] In another preferred embodiment, the LC medium comprises one or more stabilizers selected from Table D below.

[0640] The proportion of stabilizer in the LC medium is preferably from 10 to 500 ppm, very preferably from 20 to 100 ppm.

[0641] The LC media according to the invention may additionally comprise one or more other components or additives, preferably selected from the list including but not limited to: comonomers, chiral dopants, polymerization initiators, inhibitors, stabilizers, surfactants, wetting agents, lubricants, dispersants, hydrophobic agents, binders, flow improvers, defoamers, scavengers, diluents, reactive diluents, auxiliaries, colorants, dyes, pigments and nanoparticles.

[0642] 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 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 37430 and 28 53 728.

[0643] 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.

[0644] 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.

[0645] 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.

[0646] 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.

[0647] For the present invention and 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 in accordance with the following Tables A.1 to A.3. All groups 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 or alkylene radical, in each case with n, m or 1 C atoms. Preferably, n, m and 1 are independently 1, 2, 3, 4, 5, 6 or 7. Table A.1 shows the codes of the ring elements of the core structure of the compounds, Table A.2 lists the bridging units, and Table A.3 lists the meanings of the terminal group symbols on the left and right sides of the molecules. The acronyms consist of the code of the ring element with the optional linking group, followed by the first hyphen and the left-hand terminal group code, and the second hyphen and the right-hand terminal group code.

[0648] Table A.1: Ring elements

[0649]

[0650]

[0651]

[0652]

[0653] Table A.2 Bridge unit

[0654]

[0655] Table A.3 End groups

[0656]

[0657]

[0658]

[0659] where n and m are each integers, and the triple dots "..." are placeholders for other abbreviations from this table.

[0660] Table B shows illustrative structures of compounds and their respective abbreviations.

[0661] Table B

[0662] In Table B, n, m, k and l are each independently an integer, preferably 1-9, preferably 1-7, k and l may also be 0, preferably 0-4, more preferably 0 or 2, 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 Meaning C m H 2m+1 or OC m H 2m+1 .

[0663]

[0664]

[0665]

[0666]

[0667]

[0668]

[0669]

[0670]

[0671]

[0672]

[0673]

[0674]

[0675]

[0676]

[0677]

[0678]

[0679]

[0680]

[0681]

[0682]

[0683] In a preferred embodiment of the invention, the LC media according to the invention comprise one or more compounds selected from Table B.

[0684] Table C

[0685] Table C shows possible chiral dopants which can be added to the LC media according to the invention.

[0686]

[0687]

[0688] 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 of Table C.

[0689] Table D

[0690] 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, the terminal methyl groups are not shown.

[0691]

[0692]

[0693]

[0694]

[0695]

[0696]

[0697]

[0698]

[0699] 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 of table D. DETAILED DESCRIPTION

[0700] Example

[0701] 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.

[0702] In addition, the following abbreviations and symbols are used:

[0703] V0 represents the threshold voltage at 20°C, capacitive [V],

[0704] n e represents the extraordinary refractive index at 20°C and 589nm,

[0705] n o represents the ordinary refractive index at 20°C and 589nm,

[0706] △n represents the optical anisotropy at 20°C and 589nm,

[0707] ε ⊥ represents the dielectric constant perpendicular to the director at 20°C and 1kHz,

[0708] ε || represents the dielectric constant parallel to the director at 20°C and 1kHz,

[0709] Δε represents the dielectric anisotropy at 20°C and 1kHz,

[0710] cl.p., T(N,I) represents the clearing point [℃],

[0711] γ1 represents the rotational viscosity at 20°C [mPa·s],

[0712] K1 is the elastic constant at 20°C, “slope” deformation [pN],

[0713] K2 represents the elastic constant at 20°C, "torsion" deformation [pN],

[0714] K3 represents the elastic constant at 20°C, “bending” deformation [pN].

[0715] K av represents the average elastic constant [pN] at 20°C and is defined in this paper as

[0716] K av. ≡( 3 / 2K1+K3) / 3≈(K1+K2+K3) / 3

[0717] LTS stands for the low temperature stability of the phase determined in the test cell,

[0718] VHR stands for voltage holding ratio.

[0719] 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).

[0720] 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 temperature T(N,I) or clearing point 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.

[0721] 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.

[0722] The term "threshold voltage" used in the present invention relates to the capacitive threshold (V0), which is also referred to as the Freeder icks threshold unless otherwise stated. In the embodiments, the optical threshold is also generally for a relative contrast ratio of 10% (V 10 ) given.

[0723] 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.

[0724] 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.

[0725] The polymerizable compound is polymerized in the display or test cell by irradiating with UV light of defined intensity for a predetermined time while applying a voltage (typically 10V-30V AC, 1 kHz) to the display.

[0726] The tilt angle was determined using the Mueller Matrix Polarimeter "AxoScan" from Axometrics. Small values ​​(ie large deviations from an angle of 90°) correspond here to large tilts.

[0727] 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 LC molecule layer having uniform orientation, which in the case of rod-shaped, uniaxially positively birefringent LC molecules corresponds to their molecular long axis.

[0728] Example 1

[0729] Nematic LC mixture N1 was prepared as follows.

[0730]

[0731] To mixture N1 was added 100 ppm of stabilizer H-1-1-1.

[0732]

[0733] Example 2

[0734] Nematic LC mixture N2 was prepared as follows.

[0735]

[0736] To mixture N2, 150 ppm of stabilizer ST-3a-1 were added.

[0737]

[0738] Example 3

[0739] Nematic LC mixture N3 was prepared as follows.

[0740]

[0741]

[0742] To mixture N3, 150 ppm of stabilizer ST-3b-1 were added.

[0743]

[0744] Example 4

[0745] Nematic LC mixture N4 was prepared as follows.

[0746]

[0747] To mixture N4 was added 50 ppm of stabilizer H-2-1-1.

[0748]

[0749] Example 5

[0750] Nematic LC mixture N5 was prepared as follows.

[0751]

[0752] To mixture N5, 100 ppm of stabilizer ST-8-1 was added.

[0753]

[0754] Example 6

[0755] Nematic LC mixture N6 was prepared as follows.

[0756]

[0757] To mixture N6, 50 ppm of stabilizer ST-9-1 was added.

[0758]

[0759] Example 7

[0760] Nematic LC mixture N7 was prepared as follows.

[0761]

[0762] To mixture N7, 50 ppm of stabilizer ST-12 was added.

[0763]

[0764] Example 8

[0765] Nematic LC mixture N8 was prepared as follows.

[0766]

[0767] To mixture N8, 150 ppm of stabilizer ST-3a-2 were added.

[0768]

[0769] Example 9

[0770] Nematic LC mixture N9 was prepared as follows.

[0771]

[0772] To mixture N9 was added 150 ppm of stabilizer ST-3b-2.

[0773]

[0774] Example 10

[0775] Nematic LC mixture N10 was prepared as follows.

[0776]

[0777]

[0778] To mixture N10, 100 ppm of stabilizer ST-7 was added.

[0779]

[0780] Embodiment 11

[0781] Nematic LC mixture N11 was prepared as follows.

[0782]

[0783] To mixture N11, 100 ppm of stabilizer H-1-1-1 were added.

[0784] Example 12

[0785] Nematic LC mixture N12 was prepared as follows.

[0786]

[0787]

[0788] To mixture N12, 150 ppm of stabilizer ST-3a-1 were added.

[0789] Embodiment 13

[0790] Nematic LC mixture N13 was prepared as follows.

[0791]

[0792] To mixture N13, 150 ppm of stabilizer ST-3b-1 were added.

[0793] Embodiment 14

[0794] Nematic LC mixture N14 was prepared as follows.

[0795]

[0796]

[0797] To mixture N14, 50 ppm of stabilizer H-2-1-1 were added.

[0798] Embodiment 15

[0799] Nematic LC mixture N15 was prepared as follows.

[0800]

[0801] Where B(S)-4O-O2(c5) is

[0802]

[0803] To mixture N15, 100 ppm of stabilizer ST-8-1 was added.

[0804] Example 16

[0805] Nematic LC mixture N16 was prepared as follows.

[0806]

[0807] Where B(S)-1V1O-O1(c5) is

[0808]

[0809] To mixture N16, 50 ppm of stabilizer ST-9-1 were added.

[0810] Embodiment 17

[0811] Nematic LC mixture N17 was prepared as follows.

[0812]

[0813]

[0814] To mixture N17, 50 ppm of stabilizer ST-12 was added.

[0815] Embodiment 18

[0816] Nematic LC mixture N18 was prepared as follows.

[0817]

[0818] To mixture N18, 150 ppm of stabilizer ST-3a-2 were added.

[0819] Embodiment 19

[0820] Nematic LC mixture N19 was prepared as follows.

[0821]

[0822] To mixture N19, 150 ppm of stabilizer ST-3b-2 were added.

[0823] Embodiment 20

[0824] Nematic LC mixture N20 was prepared as follows.

[0825]

[0826] To mixture N20, 50 ppm of stabilizer ST-7 was added.

[0827] Embodiment 21

[0828] Nematic LC mixture N21 was prepared as follows.

[0829]

[0830] To mixture N21, 100 ppm of stabilizer H-1-1-1 were added.

[0831] Embodiment 22

[0832] Nematic LC mixture N22 was prepared as follows.

[0833]

[0834] To mixture N22, 150 ppm of stabilizer ST-3a-1 were added.

[0835] Embodiment 23

[0836] Nematic LC mixture N23 was prepared as follows.

[0837]

[0838] To mixture N23, 150 ppm of stabilizer ST-3b-1 were added.

[0839] Embodiment 24

[0840] Nematic LC mixture N24 was prepared as follows.

[0841]

[0842] To mixture N24, 50 ppm of stabilizer H-2-1-1 was added.

[0843] Embodiment 25

[0844] Nematic LC mixture N25 was prepared as follows.

[0845]

[0846] To mixture N25, 100 ppm of stabilizer ST-8-1 was added.

[0847] Embodiment 26

[0848] Nematic LC mixture N26 was prepared as follows.

[0849]

[0850] To mixture N26, 50 ppm of stabilizer ST-9-1 was added.

[0851] Embodiment 27

[0852] Nematic LC mixture N27 was prepared as follows.

[0853]

[0854] To mixture N27, 50 ppm of stabilizer ST-12 was added.

[0855] Embodiment 28

[0856] Nematic LC mixture N28 was prepared as follows.

[0857]

[0858]

[0859] To mixture N28, 150 ppm of stabilizer ST-3a-2 were added.

[0860] Embodiment 29

[0861] Nematic LC mixture N29 was prepared as follows.

[0862]

[0863] To mixture N29, 150 ppm of stabilizer ST-3b-2 were added.

[0864] Embodiment 30

[0865] Nematic LC mixture N30 was prepared as follows.

[0866]

[0867]

[0868] To mixture N30, 100 ppm of stabilizer ST-7 was added.

[0869] Embodiment 31

[0870] Nematic LC mixture N31 was prepared as follows.

[0871]

[0872] To mixture N31 was added 100 ppm of stabilizer H-1-1-1.

[0873] Embodiment 32

[0874] Nematic LC mixture N32 was prepared as follows.

[0875]

[0876]

[0877] To mixture N32, 150 ppm of stabilizer ST-3a-1 were added.

[0878] Embodiment 33

[0879] Nematic LC mixture N33 was prepared as follows.

[0880]

[0881] To mixture N33, 150 ppm of stabilizer ST-3b-1 were added.

[0882] Embodiment 34

[0883] Nematic LC mixture N34 was prepared as follows.

[0884]

[0885]

[0886] To mixture N34 was added 50 ppm of stabilizer H-2-1-1.

[0887] Embodiment 35

[0888] Nematic LC mixture N35 was prepared as follows.

[0889]

[0890] To mixture N35, 100 ppm of stabilizer ST-8-1 was added.

[0891] Embodiment 36

[0892] Nematic LC mixture N36 was prepared as follows.

[0893]

[0894] To mixture N36 was added 50 ppm of stabilizer ST-9-1.

[0895] Embodiment 37

[0896] Nematic LC mixture N37 was prepared as follows.

[0897]

[0898] To mixture N37, 50 ppm of stabilizer ST-12 was added.

[0899] Embodiment 38

[0900] Nematic LC mixture N38 was prepared as follows.

[0901]

[0902] To mixture N38, 150 ppm of stabilizer ST-3a-2 were added.

[0903] Embodiment 39

[0904] Nematic LC mixture N39 was prepared as follows.

[0905]

[0906] To mixture N39 was added 150 ppm of stabilizer ST-3b-2.

[0907] Embodiment 40

[0908] Nematic LC mixture N40 was prepared as follows.

[0909]

[0910] To mixture N40, 50 ppm of stabilizer ST-7 was added.

[0911] Embodiment 41

[0912] Nematic LC mixture N41 was prepared as follows.

[0913]

[0914] To mixture N41, 100 ppm of stabilizer H-1-1-1 were added.

[0915] Embodiment 42

[0916] Nematic LC mixture N42 was prepared as follows.

[0917]

[0918] To mixture N42, 150 ppm of stabilizer ST-3a-1 were added.

[0919] Embodiment 43

[0920] Nematic LC mixture N43 was prepared as follows.

[0921]

[0922]

[0923] To mixture N43, 150 ppm of stabilizer ST-3b-1 were added.

[0924] Embodiment 44

[0925] Nematic LC mixture N44 was prepared as follows.

[0926]

[0927] To mixture N44, 50 ppm of stabilizer H-2-1-1 was added.

[0928] Embodiment 45

[0929] Nematic LC mixture N45 was prepared as follows.

[0930]

[0931]

[0932] To mixture N45, 100 ppm of stabilizer ST-8-1 was added.

[0933] Embodiment 46

[0934] Nematic LC mixture N46 was prepared as follows.

[0935]

[0936] To mixture N46, 50 ppm of stabilizer ST-9-1 was added.

[0937] Embodiment 47

[0938] Nematic LC mixture N47 was prepared as follows.

[0939]

[0940]

[0941] To mixture N47, 50 ppm of stabilizer ST-12 was added.

[0942] Embodiment 48

[0943] Nematic LC mixture N48 was prepared as follows.

[0944]

[0945] To mixture N48, 150 ppm of stabilizer ST-3a-2 were added.

[0946] Embodiment 49

[0947] Nematic LC mixture N49 was prepared as follows.

[0948]

[0949] To mixture N49 was added 150 ppm of stabilizer ST-3b-2.

[0950] Embodiment 50

[0951] Nematic LC mixture N50 was prepared as follows.

[0952]

[0953] To mixture N50, 50 ppm of stabilizer ST-7 was added.

[0954] Embodiment 51

[0955] Nematic LC mixture N51 was prepared as follows.

[0956]

[0957] To mixture N51 was added 100 ppm of stabilizer H-1-1-1.

[0958] Embodiment 52

[0959] Nematic LC mixture N52 was prepared as follows.

[0960]

[0961] To mixture N52, 150 ppm of stabilizer ST-3a-1 were added.

[0962] Embodiment 53

[0963] Nematic LC mixture N53 was prepared as follows.

[0964]

[0965]

[0966] To mixture N53, 150 ppm of stabilizer ST-3b-1 were added.

[0967] Embodiment 54

[0968] Nematic LC mixture N54 was prepared as follows.

[0969]

[0970] To mixture N54 was added 50 ppm of stabilizer H-2-1-1.

[0971] Embodiment 55

[0972] Nematic LC mixture N55 was prepared as follows.

[0973]

[0974]

[0975] To mixture N55, 100 ppm of stabilizer ST-8-1 was added.

[0976] Embodiment 56

[0977] Nematic LC mixture N56 was prepared as follows.

[0978]

[0979] To mixture N56 was added 50 ppm of stabilizer ST-9-1.

[0980] Embodiment 57

[0981] Nematic LC mixture N57 was prepared as follows.

[0982]

[0983]

[0984] To mixture N57, 50 ppm of stabilizer ST-12 was added.

[0985] Embodiment 58

[0986] Nematic LC mixture N58 was prepared as follows.

[0987]

[0988] To mixture N58, 150 ppm of stabilizer ST-3a-2 were added.

[0989] Embodiment 59

[0990] Nematic LC mixture N59 was prepared as follows.

[0991]

[0992]

[0993] To mixture N59 was added 150 ppm of stabilizer ST-3b-2.

[0994] Embodiment 60

[0995] Nematic LC mixture N60 was prepared as follows.

[0996]

[0997] To mixture N60, 50 ppm of stabilizer ST-7 was added.

[0998] Embodiment 61

[0999] Nematic LC mixture N61 was prepared as follows.

[1000]

[1001] To mixture N61, 100 ppm of stabilizer H-1-1-1 was added.

[1002] Embodiment 62

[1003] Nematic LC mixture N62 was prepared as follows.

[1004]

[1005] To mixture N62, 150 ppm of stabilizer ST-3a-1 were added.

[1006] Embodiment 63

[1007] Nematic LC mixture N63 was prepared as follows.

[1008]

[1009] To mixture N63, 150 ppm of stabilizer ST-3b-1 were added.

[1010] Embodiment 64

[1011] Nematic LC mixture N64 was prepared as follows.

[1012]

[1013] To mixture N64 was added 50 ppm of stabilizer H-2-1-1.

[1014] Embodiment 65

[1015] Nematic LC mixture N65 was prepared as follows.

[1016]

[1017] To mixture N65, 100 ppm of stabilizer ST-8-1 was added.

[1018] Embodiment 66

[1019] Nematic LC mixture N66 was prepared as follows.

[1020]

[1021] To mixture N66, 50 ppm of stabilizer ST-9-1 was added.

[1022] Embodiment 67

[1023] Nematic LC mixture N67 was prepared as follows.

[1024]

[1025] To mixture N67, 50 ppm of stabilizer ST-12 was added.

[1026] Embodiment 68

[1027] Nematic LC mixture N68 was prepared as follows.

[1028]

[1029] To mixture N68, 150 ppm of stabilizer ST-3a-2 was added.

[1030] Embodiment 69

[1031] Nematic LC mixture N69 was prepared as follows.

[1032]

[1033] To mixture N69 was added 150 ppm of stabilizer ST-3b-2.

[1034] Embodiment 70

[1035] Nematic LC mixture N70 was prepared as follows.

[1036]

[1037] To mixture N70, 50 ppm of stabilizer ST-7 was added.

[1038] Embodiment 71

[1039] Nematic LC mixture N71 was prepared as follows.

[1040]

[1041] To mixture N71 was added 100 ppm of stabilizer H-1-1-1.

[1042] Embodiment 72

[1043] Nematic LC mixture N72 was prepared as follows.

[1044]

[1045] To mixture N72, 150 ppm of stabilizer ST-3a-1 were added.

[1046] Embodiment 73

[1047] Nematic LC mixture N73 was prepared as follows.

[1048]

[1049] To mixture N73, 150 ppm of stabilizer ST-3b-1 was added.

[1050] Embodiment 74

[1051] Nematic LC mixture N74 was prepared as follows.

[1052]

[1053] To mixture N74 was added 50 ppm of stabilizer H-2-1-1.

[1054] Embodiment 75

[1055] Nematic LC mixture N75 was prepared as follows.

[1056]

[1057] To mixture N75, 100 ppm of stabilizer ST-8-1 was added.

[1058] Embodiment 76

[1059] Nematic LC mixture N76 was prepared as follows.

[1060]

[1061]

[1062] To mixture N76 was added 50 ppm of stabilizer ST-9-1.

[1063] Embodiment 77

[1064] Nematic LC mixture N77 was prepared as follows.

[1065]

[1066] To mixture N77, 50 ppm of stabilizer ST-12 was added.

[1067] Embodiment 78

[1068] A polymerizable mixture was prepared by adding 0.3% of polymerizable compound RM-171 to the mixture of Example 1.

[1069]

[1070] Embodiment 79

[1071] A polymerizable mixture was prepared by adding 0.3% of polymerizable compound RM-1 to the mixture of Example 2.

[1072]

[1073] Embodiment 80

[1074] A polymerizable mixture was prepared by adding 0.3% of polymerizable compound RM-35 to the mixture of Example 3.

[1075]

[1076] Embodiment 81

[1077] A polymerizable mixture was prepared by adding 0.3% of polymerizable compound RM-172 to the mixture of Example 4.

[1078]

[1079] Embodiment 82

[1080] A polymerizable mixture was prepared by adding 0.4% of polymerizable compound RM-64 to the mixture of Example 5.

[1081]

[1082] Embodiment 83

[1083] Nematic LC mixture N83 was prepared as follows:

[1084]

[1085] To mixture N83, 150 ppm of stabilizer ST-3a-1 was added.

[1086] Embodiment 84

[1087] Nematic LC mixture N84 was prepared as follows:

[1088]

[1089]

[1090] Among them, B(S)-4O-O1(c5) is

[1091]

[1092] B(S)-4O-O1(c5)

[1093] To mixture N84, 150 ppm of stabilizer ST-3a-2 was added.

[1094] Embodiment 85

[1095] Nematic LC mixture N85 was prepared as follows:

[1096]

[1097]

[1098] To mixture N85, 100 ppm of stabilizer ST-3a-1 and 50 ppm of stabilizer ST-12 were added.

[1099] Embodiment 86

[1100] Nematic LC mixture N86 was prepared as follows:

[1101]

[1102] To mixture N86, 100 ppm of stabilizer ST-3a-2 and 50 ppm of stabilizer ST-12 were added.

[1103] Embodiment 87

[1104] Nematic LC mixture N87 was prepared as follows:

[1105]

[1106]

[1107] To mixture N87, 100 ppm of stabilizer ST-3a-1 and 50 ppm of stabilizer ST-8-1 were added.

[1108] Embodiment 88

[1109] Nematic LC mixture N88 was prepared as follows:

[1110]

[1111] To mixture N88, 100 ppm of stabilizer ST-3a-2 and 50 ppm of stabilizer ST-8-1 were added.

Claims

1. A liquid-crystalline medium comprising one or more compounds of the formula IA, and One or more compounds of formula IB in R A1 ,R A2 ,R B1 and R B2 each independently of one another represents H, a straight-chain or branched alkyl or alkoxy radical having 1 to 15 C atoms, preferably having 1 to 7 C atoms, wherein in these radicals one or more -CH2- radicals can each independently of one another be replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- are substituted in such a way that the O atoms are not directly connected to each other, and wherein one or more H atoms may be replaced by halogen, express Z 1 ,Z 2 Each independently represents a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF-, -CH=CHCH2O, Y represents H or CH3, n represents 0 or 1.

2. 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 and IIE, where the individual radicals have the following meanings, identically or differently, independently of one another on each occurrence: R 21 ,R 22 is H, alkyl, alkoxy or alkenyl, having up to 15 C atoms, which is unsubstituted or monosubstituted by F, Cl, CN or CF3, wherein in addition, in these radicals one or more CH2 groups may be replaced by -O-, -S-, -C≡C-, -CF2O-, -OCF2-, -OC-O-, -O-CO-, in such a way that the 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.

3. A liquid crystal medium according to any one of claims 1 or 2, wherein the medium comprises one or more compounds of formula III in R 31 and R 32 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 in these radicals one or more -CH2- radicals may each independently of one another be replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, are replaced by -O-, -CO-O- or -O-CO- in such a way that the O atoms are not directly connected to each other and one or more H atoms may be replaced by halogen, A 3 Each occurrence independently of one another represents 1,4-phenylene, in which one or two CH groups may be replaced by N, or 1,4-cyclohexylene or 1,4-cyclohexenylene, in which one or two non-adjacent CH2 groups may be replaced by -O- or -S-, where the groups may be mono- or polysubstituted by halogen atoms, n represents 0, 1 or 2, Z 3 Each occurrence independently represents -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -CH=CH-, -C≡C- or a single bond, L 31 and L 32 each independently represents F, Cl, CF3 or CHF2, and Y 1 ,Y 2 ,Y 3 and Y 4 Each independently represents H, F, Cl, CF3, CHF2, CH3 or OCH3.

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, in 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 the formula IV, in R 41 represents an unsubstituted alkyl group having 1 to 7 C atoms, or a cycloalkyl 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 cycloalkyl 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 represent an alkyl group having 1 to 7 C atoms or a cycloalkyl group having 3 to 6 C atoms, and Alkenyl denotes an alkenyl group 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 represent straight-chain alkyl having 1 to 6 C atoms or cycloalkyl 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 and R 52 represents an alkyl group having 1 to 7 C atoms, or a cycloalkyl 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 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 compounds of 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 BC, CR, PH-1 and PH-2. 11 . The liquid-crystalline medium according to claim 1 , wherein the medium additionally 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 claim 1 .

13. The display of 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. 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 other LC compounds and / or additives.

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