Liquid crystal medium

Abstract

The invention relates to liquid-crystalline media comprising one or more compounds of the formula IA in which the radicals occurring have the meanings indicated in claim 1, and to the use of said liquid-crystalline media in active-matrix displays, in particular in VA, IPS, U-IPS, FFS, UB-FFS, SA-VA, SA-FFS, PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS, PS-posi-VA, PS-TN, polymer-stabilized SA-VA or polymer-stabilized SA-FFS displays. #imgabs0#

Description

Technical Field

[0001] The present invention relates to liquid crystal (LC) media and to the use of said LC media for optical, electrooptical and electronic purposes, in particular in LC displays, especially in IPS, FFS, VA or PS-VA displays. Background Art

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

[0003] Furthermore, so-called VA ("vertically aligned") displays are known, which have a wider viewing angle. The LC cell of a VA display contains a layer of LC medium between two transparent electrodes, wherein the LC medium generally has a negative dielectric anisotropy. In the off state, the molecules of the LC layer are aligned perpendicularly to the electrode surfaces (homeotropically) or have a tilted homeotropic alignment. When a voltage is applied to the two electrodes, a realignment of the LC molecules parallel to the electrode surfaces occurs.

[0004] Also known are so-called IPS (in-plane switching) displays, which contain an LC layer between two substrates, wherein two electrodes are arranged on only one of the two substrates and which preferably have a mutually meshing comb-shaped structure. When a voltage is applied to the electrodes, an electric field with a significant component parallel to the LC layer is thus generated between them. This leads to a realignment of the LC molecules in the plane of the layer.

[0005] In addition, so-called FFS ("fringe field switching") displays have been reported (see in particular SH Jung et al., Jpn. J. Appl. Phys., Vol. 43, No. 3, 2004, 1028), which contain two electrodes on the same substrate, one of which is structured in a comb-like manner and the other is unstructured. This produces a strong so-called "fringe field", i.e. a strong electric field close to the edge of the electrode, and an electric field with both a strong vertical component and a strong horizontal component throughout the liquid crystal cell. FFS displays have a low viewing angle dependence of the contrast. FFS displays usually contain an LC medium with positive dielectric anisotropy and an alignment layer, usually composed of polyimide, which provides a planar alignment of the molecules of the LC medium.

[0006] FFS displays can be operated as active matrix or passive matrix displays. In the case of active matrix displays, the individual pixels are typically addressed by integrated non-linear active elements such as transistors (e.g. thin film transistors ("TFT")), while in the case of passive matrix displays, the individual pixels are typically addressed by multiplexing methods, as known from the prior art.

[0007] In addition, FFS displays have been disclosed (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 have similar electrode designs and layer thicknesses as FFS displays, but contain a layer of LC medium with negative dielectric anisotropy instead of LC medium with positive dielectric anisotropy. The LC medium with negative dielectric anisotropy shows a more favorable director orientation with a smaller tilt and a larger twist orientation than the LC medium with positive dielectric anisotropy, so that these displays have higher transmission. The display further comprises an alignment layer provided on at least one of the substrates, preferably an alignment layer of polyimide, which is in contact with the LC medium and induces a planar alignment of the LC molecules of the LC medium. These displays are also referred to as "ultra-brightness FFS (UB-FFS)" mode displays. These displays require LC media with high reliability.

[0008] In this context, the term "reliability" means the performance quality of the display over time and under different stress loads, such as light load, temperature, humidity, voltage, and the term encompasses display effects such as afterimages (area and line afterimages), brightness unevenness (mura), smearing (yogore), etc., which are known to the person skilled in the art in the field of LC displays. As a standard parameter for classifying the 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. A high VHR is, among other factors, a prerequisite for a high reliability of the LC medium.

[0009] In the latest types of VA displays, the homogeneous alignment of the LC molecules is restricted to a plurality of relatively small domains within the LC cell. Between these domains there may be disclinations, which are also referred to as tilted domains. VA displays with tilted domains have a greater viewing angle dependence of the contrast and the grayscale than conventional VA displays. Furthermore, displays of this type are simpler to produce, since additional treatment of the electrode surfaces for homogeneous alignment of the molecules in the switched-on state, for example by rubbing, is no longer necessary. Instead, the preferential direction of the tilt or pre-tilt angle is controlled by a special design of the electrodes.

[0010] In so-called MVA ("Multi-domain Vertical Alignment") displays, this is usually achieved by electrodes having protrusions which cause a local pretilt. Thus, when a voltage is applied, the LC molecules align parallel to the electrode surface in different directions in different defined areas of the liquid crystal cell. "Controlled" switching is thereby achieved and the formation of interfering disclination lines is prevented. Although this arrangement improves the viewing angle of the display, it leads to a reduction in its transparency to light. A further development of MVA uses protrusions on only one electrode side, while the counter electrode has slits, which improves the transparency to light. When a voltage is applied, the slit electrode generates an inhomogeneous electric field in the LC cell, which means that controlled switching is still achieved. In order to further improve the transparency to light, the spacing between the slits and the protrusions can be increased, but this in turn leads to a prolongation of the response time. In so-called PVA ("patterned VA") displays, the protrusions are made completely superfluous, since both electrodes are structured by means of slits on opposite sides, which leads to increased contrast and improved transparency to light, but is technically difficult and makes the display more sensitive to mechanical influences ("tap" etc.). However, for many applications, such as monitors and especially TV screens, a reduction in the response time of the display and an improvement in contrast and brightness (transmission) are required.

[0011] A further development are the so-called PS ("polymer-stabilized") or PSA ("polymer-stabilized alignment") type displays, for which the term "polymer-stabilized" is also occasionally used. In these displays, small amounts (e.g. 0.3% by weight, typically <1% by weight) of one or more polymerizable compounds, preferably polymerizable monomeric compounds, are added to the LC medium and, after the LC medium has been filled into the display, are polymerized, usually by UV light, optionally in situ while applying a voltage to the electrodes of the display. The polymerization is carried out at a temperature at which the LC medium exhibits a liquid-crystalline phase, usually at room temperature. The addition of polymerizable mesogenic or liquid-crystalline compounds, also known as reactive mesogens or "RMs", to the LC mixture has proven to be particularly suitable.

[0012] Unless otherwise stated, in the following the term "PSA" is used when referring generally to polymer-stabilized alignment displays and the term "PS" is used when referring to specific display modes like PS-VA, PS-TN and similar modes.

[0013] Likewise, unless otherwise indicated, in the following the term "RM" is used when referring to polymerisable mesogenic or liquid crystal compounds.

[0014] At the same time, the PS(A) principle is used in various conventional LC display modes. Thus, for example, PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS and PS-TN displays are known. The polymerization of the RM preferably occurs with applied voltage in the case of PS-VA and PS-OCB displays, and with or without applied voltage, preferably without applied voltage, in the case of PS-IPS displays. As can be confirmed in test liquid crystal cells, the PS(A) method leads to a pretilt in the liquid crystal cell. In the case of PS-VA displays, the pretilt has a positive effect on the response time. For PS-VA displays, standard MVA or PVA pixel and electrode arrangements can be used. However, in addition, it is also possible, for example, to process with only one structured electrode side and without protrusions, which significantly simplifies the production and at the same time leads to very good contrast and very good transparency to light.

[0015] PS-VA displays are described, for example, in EP 1 170 626 A2, US 6,861,107, US 7,169,449, US 2004 / 0191428 A1, US 2006 / 0066793 A1 and US 2006 / 0103804 A1. PS-OCB displays are described, for example, in T.-J-Chen et al., Jpn. J. Appl. Phys. 45, 2006, 2702-2704 and S H Kim, L.-C-Chien, Jpn. J. Appl. Phys. 43, 2004, 7643-7647. PS-IPS displays are described, for example, in US 6,177,972 and Appl. Phys. Lett. 1999, 75 (21), 3264. PS-TN displays are described, for example, in Optics Express 2004, 12(7), 1221.

[0016] Liquid-crystalline media suitable for use in displays of the type mentioned above according to the invention are also disclosed in EP17161352.

[0017] Another problem observed in the prior art is that LC media for use in PSA displays (including but not limited to displays of the PSA type) often exhibit high viscosities and, therefore, high switching times. In order to reduce the viscosity and switching times of the LC media, it has been proposed in the prior art to add LC compounds having alkenyl groups. However, it has been observed that LC media containing alkenyl compounds often show a reduction in reliability and stability, and a reduction in VHR, especially after exposure to UV radiation. This is particularly disadvantageous for applications in PSA displays, in particular, since the photopolymerization of the RMs in the PSA displays is usually carried out by exposure to UV radiation, which may result in a reduction in the VHR in the LC media.

[0018] Furthermore, there is a great need for PSA displays and LC media and polymerizable compounds used in such PSA displays which enable a high specific resistance to be achieved over a large operating temperature range, short response times, even at low temperatures, and which enable low threshold voltages, low pretilt angles, multiple grayscales, high contrast and wide viewing angles, which have high reliability and high values ​​of VHR after UV exposure, and in the case of polymerizable compounds, low melting points and high solubility in LC host mixtures. In PSA displays for mobile applications, it is particularly desirable to have available LC media which exhibit low threshold voltages and high birefringence.

[0019] There is therefore still a strong need for LC media for use in such displays which do not exhibit the disadvantages described above, or exhibit them only to a small extent, and which have improved properties. None of the series of compounds disclosed to date which have liquid-crystalline mesophases comprises a single compound which meets all these requirements. Therefore, in order to obtain substances which can be used as LC phases, mixtures of 2 to 25, preferably 3 to 18, compounds are usually prepared. However, it has not yet been possible to easily prepare the optimal phases in this way, since liquid-crystalline materials having a significantly negative dielectric anisotropy and sufficient long-term stability have hitherto been unavailable. Summary of the invention

[0020] The present invention was based on the object of providing novel materials suitable for use in LC media in PSA displays, which LC media optionally comprise reactive mesogens (RMs), which materials do not have the disadvantages indicated above or have them to a reduced extent.

[0021] Furthermore, it is an object of the present invention to provide alternative media to the existing media known to the person skilled in the art, in order to broaden the range of available materials which allows a more specific optimization for a particular display.

[0022] These objects have been achieved according to the invention by means of materials and methods as described in the present application.In particular, it has surprisingly been found that the use of a liquid crystal host as described below allows to achieve the advantageous effects as mentioned above.

[0023] The present invention relates to LC media comprising one or more compounds of formula IA

[0024]

[0025] in

[0026] R 11 , R 12 Identically or differently represent H, alkyl or alkoxy having 1 to 15 C atoms, wherein one or more CH2 groups in these radicals are optionally independently of one another replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, —O—, —CO—O— or —O—CO— is substituted in such a way that the O atoms are not directly connected to one another, and wherein in addition one or more H atoms may be replaced by halogen.

[0027] This type of medium can be used in particular for electro-optical displays with active matrix addressing based on the ECB effect and for IPS (in-plane switching) displays or FFS (fringe field switching) displays. The medium is characterized by a surprisingly low rotational viscosity and a high clearing temperature combined with a high voltage holding ratio. This and the wide nematic phase range of the medium and the excellent low temperature stability at -20°C and -30°C enable displays with a wide operating temperature range, fast switching times and excellent stability in the case of deep temperature storage.

[0028] The mixture according to the invention is further characterized in that, in addition to the improvement of the rotational viscosity γ1, a relatively high elastic constant K for improving the response time can be observed. 33 The use of compounds of the formula IA in LC mixtures, which preferably have a negative dielectric anisotropy, reduces the ratio of the rotational viscosity γ1 to the elastic constant K1.

[0029] Preferred embodiments of the invention are defined in the dependent claims and pointed out below.

[0030] The liquid-crystalline media according to the invention, which are also referred to herein as liquid-crystalline host mixtures, are suitable for use in polymer-stabilized displays. For this purpose, the media according to the invention optionally comprise one or more polymerizable compounds of the formula P

[0031] P-Sp-A 1 -(Z 1 -A2 ) z -RP

[0032] The individual radicals, independently of one another and identically or differently on each occurrence, have the following meanings:

[0033] P polymerizable group,

[0034] Sp spacer group or single bond,

[0035] A 1 , A 2 an aromatic, heteroaromatic, alicyclic or heterocyclic radical, which preferably has 4 to 25 ring atoms, which may also contain fused rings, and which is unsubstituted or mono- or polysubstituted by L,

[0036] Z 1 -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -(CH2) n1 -, -CF2CH2-, -CH2CF2-, -(CF2) n1 -, -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C≡C-, -CH=CH-CO-O-, -O-CO-CH=CH-, -CH2-CH2-CO-O-, -O-CO-CH2-CH2-, -CR 0 R 00 - or single key,

[0037] R 0 , R 00 H or alkyl having 1 to 12 C atoms,

[0038] RH, L or P-Sp-,

[0039] LF, Cl, -CN, P-Sp- or linear, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH2 groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that the O and / or S atoms are not directly connected to one another, and wherein one or more H atoms are each optionally replaced by P-Sp-, F or Cl,

[0040] z0, 1, 2, or 3,

[0041] n11, 2, 3, or 4.

[0042] As used herein, the terms "active layer" and "switchable layer" are meant to refer to a layer in an electro-optical display (e.g. an LC display) which comprises one or more molecules, e.g. LC molecules, having structural and optical anisotropy, which molecules change their orientation when subjected to an external stimulus (e.g. an electric or magnetic field), resulting in a change in the transmission of the layer to polarized or unpolarized light.

[0043] As used herein, the terms "tilt" and "tilt angle" are to be understood as meaning the tilted alignment of the LC molecules of an LC medium relative to the surface of the liquid crystal cell in an LC display, here preferably a PSA display. The tilt angle here denotes the average angle (<90°) between the longitudinal molecular axes of the LC molecules (LC director) and the surfaces of the plane-parallel outer plates forming the LC cell. Low values ​​of the tilt angle (i.e. large deviations from an angle of 90°) correspond here to large tilts. Suitable methods for measuring the tilt angle are given in the examples. Unless otherwise indicated, the tilt angle values ​​disclosed above and below relate to this measurement method.

[0044] As used herein, the terms "reactive mesogen" and "RM" will be understood to mean a compound containing a mesogenic or liquid crystal backbone and attached thereto one or more functional groups suitable for polymerization and also referred to as "polymerizable groups" or "P".

[0045] Unless otherwise stated, the term "polymerizable compound" as used herein will be understood to mean a polymerizable monomeric compound.

[0046] As used herein, the term "low molecular weight compound" will be understood to mean a monomeric compound as opposed to a "polymeric compound" or "polymer" and / or a compound that is not prepared by polymerization.

[0047] As used herein, the term "non-polymerizable compound" will be understood to mean a compound that does not contain a functional group suitable for polymerization under the conditions normally applied for the polymerization of RMs.

[0048] The term "mesogenic group" as used herein is known to those skilled in the art and is described in the literature and means a group which, due to the anisotropy of its attractive and repulsive interactions, contributes substantially to the formation of a liquid crystal (LC) phase in a low molecular weight or polymeric substance. A compound containing a mesogenic group (mesogenic compound) does not necessarily have to have an LC phase itself. A mesogenic compound may also exhibit LC phase characteristics only after mixing with other compounds and / or after polymerization. Typical mesogenic groups are, for example, rigid rods or disc-shaped units. An overview of the terms and definitions used in connection with mesogenic or LC compounds is given in the following literature: Pure Appl. Chem. 2001, 73 (5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368.

[0049] As used herein, the terms "optically active" and "chiral" are synonymous with materials that are capable of inducing a helical pitch in a nematic host material, which are also referred to as "chiral dopants."

[0050] As used herein, the term "spacer", hereinafter also referred to as "Sp", is known to the person skilled in the art and is described in the literature, see for example Pure Appl. Chem. 2001, 73 (5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368. As used herein, the term "spacer" or "spacer" means a flexible group, such as an alkylene group, which connects the mesogenic group and the one or more polymerizable groups in a polymerizable mesogenic compound.

[0051] Above and below, represents a trans-1,4-cyclohexylene ring,

[0052] and It represents a 1,4-phenylene ring.

[0053] In the group In the phenyl ring, a single bond shown between two ring atoms may be attached to any free position of the benzene ring.

[0054] Above and below, "organic group" means a carbon or hydrocarbon group.

[0055] "Carbon group" means a mono- or polyvalent organic group containing at least one carbon atom, wherein such a group either contains no additional atoms (e.g. -C≡C-) or optionally contains one or more additional atoms, such as N, O, S, B, P, Si, Se, As, Te or Ge (e.g. carbonyl, etc.). The term "hydrocarbon group" means a carbon group which additionally contains one or more H atoms and optionally one or more heteroatoms, such as N, O, S, B, P, Si, Se, As, Te or Ge.

[0056] "Halogen" means F, Cl, Br or I, preferably F or Cl.

[0057] -CO-, -C(=O)- and -C(O)- represent carbonyl groups, i.e.

[0058] The carbon or hydrocarbon group can be a saturated or unsaturated group. An unsaturated group is, for example, an aryl, alkenyl or alkynyl group. The carbon or hydrocarbon group with more than 3 C atoms can be straight-chain, branched and / or cyclic and can also contain spiro-connected or fused rings.

[0059] The terms "alkyl," "aryl," "heteroaryl," and the like also encompass multivalent groups such as alkylene, arylene, heteroarylene, and the like.

[0060] The term "aryl" means an aromatic carbon group or a group derived therefrom. The term "heteroaryl" means an "aryl" as defined above containing one or more heteroatoms, preferably selected from N, O, S, Se, Te, Si and Ge.

[0061] Preferred carbon and hydrocarbon radicals are optionally substituted straight-chain, branched or cyclic alkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy radicals having 1 to 40, preferably 1 to 20 and very preferably 1 to 12 C atoms, optionally substituted aryl or aryloxy radicals having 5 to 30, preferably 6 to 25 C atoms, or optionally substituted alkylaryl, arylalkyl, alkylaryloxy, arylalkyloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy radicals having 5 to 30, preferably 6 to 25 C atoms, where one or more C atoms may also be replaced by heteroatoms which are preferably selected from N, O, S, Se, Te, Si and Ge.

[0062] Further preferred carbon and hydrocarbon groups are C1-C 20 Alkyl, C2-C 20 Alkenyl, C2-C 20 Alkynyl, C3-C 20 Allyl, C4-C 20 Alkyldiene, C4-C 20Polyene, C6-C 20 Cycloalkyl, C4-C 15 Cycloalkenyl, C6-C 30 Aryl, C6-C 30 Alkyl aryl, C6-C 30 Arylalkyl, C6-C 30 Alkyl aryloxy, C6-C 30 Arylalkyloxy, C2-C 30 Heteroaryl, C2-C 30 Heteroaryloxy.

[0063] C1-C 12 Alkyl, C2-C 12 Alkenyl, C2-C 12 Alkynyl, C6-C 25 Aryl and C2-C 25 Heteroaryl.

[0064] Further preferred carbon and hydrocarbon radicals are straight-chain, branched or cyclic alkyl radicals having 1 to 20, preferably 1 to 12, C atoms, which are unsubstituted or mono- or polysubstituted by F, Cl, Br, I or CN, and in which one or more non-adjacent CH2 groups may each be replaced independently of one another by -C(R x )=C(R x )-、-C≡C-、-N(R x )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- are replaced in such a way that the O and / or S atoms are not directly connected to each other.

[0065] R x Preferably it is H, F, Cl, CN, a straight-chain, branched or cyclic alkyl chain having 1 to 25 C atoms, in which, in addition, one or more non-adjacent C atoms may be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- and in which one or more H atoms may be replaced by F or Cl, or an optionally substituted aryl or aryloxy group having 6 to 30 C atoms, or an optionally substituted heteroaryl or heteroaryloxy group having 2 to 30 C atoms.

[0066] Preferred alkyl groups are, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, n-hexyl, cyclohexyl, 2-ethylhexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, dodecyl, trifluoromethyl, perfluoro-n-butyl, 2,2,2-trifluoroethyl, perfluorooctyl, perfluorohexyl, and the like.

[0067] Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl and the like.

[0068] Preferred alkynyl groups are, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, octynyl and the like.

[0069] Preferred alkoxy groups are, for example, methoxy, ethoxy, 2-methoxyethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, 2-methylbutoxy, n-pentoxy, n-hexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, n-undecyloxy, n-dodecyloxy, and the like.

[0070] Preferred amino groups are, for example, dimethylamino, methylamino, methylphenylamino, phenylamino and the like.

[0071] Aryl and heteroaryl groups can be monocyclic or polycyclic, i.e. they can contain one ring (e.g. phenyl) or two or more rings, which can also be fused (e.g. naphthyl) or covalently bonded (e.g. biphenyl), or contain a combination of fused and linked rings. Heteroaryl groups contain one or more heteroatoms, which are preferably selected from O, N, S and Se.

[0072] Particularly preferred are mono-, bi- or tricyclic aryl radicals having 6 to 25 C atoms and mono-, bi- or tricyclic heteroaryl radicals having 5 to 25 ring atoms, which optionally contain fused rings and are optionally substituted. Further preference is given to 5-, 6- or 7-membered aryl and heteroaryl radicals, in which in addition one or more CH groups may be replaced by N, S or O in such a way that the O atoms and / or S atoms are not directly connected to one another.

[0073] Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl, [1,1':3',1"]terphenyl-2'-yl, naphthyl, anthracene, binaphthyl, phenanthrene, 9,10-dihydro-phenanthrene, pyrene, dihydropyrene, Perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene group, etc.

[0074] Preferred heteroaryl groups are, for example, 5-membered rings such as pyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, furan, thiophene, selenophene, Azoles, Isopropylamine Azoles, 1,2-thiazoles, 1,3-thiazoles, 1,2,3- Oxadiazole, 1,2,4- Oxadiazole, 1,2,5- Oxadiazole, 1,3,4- oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole group, a 6-membered ring such as pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine group, or a fused group such as indole, isoindole, indolizine, indazole, benzimidazole, benzotriazole, purine, naphthyimidazole, phenanthimidazole, pyridimidazole, pyrazimidazole, quinoxalimidazole, benzoimidazole Azoles, naphtho Azoles, anthracenes Azoles, phenanthracenes Azoles, Isopropylamine azole, benzothiazole, benzofuran, isobenzofuran, dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, benzisoquinoline, acridine, phenothiazine, phen oxazine, benzopyridazine, benzopyrimidine, quinoxaline, phenazine, naphthyridine, azacarbazole, benzocarboline, phenanthridine, phenanthroline, thieno[2,3b]thiophene, thieno[3,2b]thiophene, dithienothiophene, isobenzothiophene, dibenzothiophene, benzothiophene, benzothiadiazolothiophene group, or a combination of these groups.

[0075] The aryl and heteroaryl groups mentioned above and below may also be substituted by alkyl, alkoxy, thioalkyl, fluorine, fluoroalkyl or further aryl or heteroaryl groups.

[0076] The (non-aromatic) alicyclic and heterocyclic groups include both saturated rings, i.e. those containing only single bonds, and partially unsaturated rings, i.e. those which may also contain multiple bonds. The heterocyclic rings contain one or more heteroatoms which are preferably selected from Si, O, N, S and Se.

[0077] The (non-aromatic) alicyclic and heterocyclic groups can be monocyclic, i.e. contain only one ring (e.g. cyclohexane), or polycyclic, i.e. contain multiple rings (e.g. decalin or bicyclooctane). Saturated groups are particularly preferred. Further preferred are mono, di or tricyclic groups with 5 to 25 ring atoms, which optionally contain fused rings and are optionally substituted. Further preferred are 5-, 6-, 7- or 8-membered carbocyclic groups, wherein in addition, one or more C atoms may be substituted by Si and / or one or more CH groups may be substituted by N and / or one or more non-adjacent CH2 groups may be substituted by-O- and / or-S-.

[0078] Preferred alicyclic and heterocyclic groups are, for example, 5-membered groups such as cyclopentane, tetrahydrofuran, tetrahydrothiofuran, pyrrolidine groups, 6-membered groups such as cyclohexane, silacyclohexane, cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1,3-dihydropyran, 1,4-dihydropyran, 1,5-dihydropyran, 1,6 ... alkane, 1,3-dithiane, piperidine group, 7-membered group, such as cycloheptane group, and condensed group, such as tetrahydronaphthalene, decahydronaphthalene, indane group, bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, octahydro-4,7-methyleneindan-2,5-diyl.

[0079] Preferred substituents are, for example, solubility promoting groups, such as alkyl or alkoxy groups, electron withdrawing groups, such as fluorine, nitro or nitrile, or substituents which increase the glass transition temperature (Tg) in the polymer, especially bulky groups, such as tert-butyl or optionally substituted aryl groups.

[0080] Hereinafter also referred to as “L S Preferred substituents of " 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, linear or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, each having 1 to 25 C atoms, wherein one or more H atoms may optionally be replaced by F or Cl, optionally substituted silyl having 1 to 20 Si atoms, or optionally substituted aryl having 6 to 25, preferably 6 to 15, C atoms,

[0081] Where R x represents H, F, Cl, CN or a straight-chain, branched or cyclic alkyl radical 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 one another, and wherein one or more H atoms are each optionally replaced by F, Cl, P- or P-Sp-, and

[0082] Y 1 Represents halogen.

[0083] "Substituted silyl or aryl" preferably means substituted with halogen, -CN, R 0 、-OR 0 、-CO-R 0 、-CO-OR 0 、-O-CO-R 0 OR-O-CO-OR 0 Substituted, where R 0 represents H or an alkyl group having 1 to 20 C atoms.

[0084] Particularly preferred substituents L are, for example, F, Cl, CN, NO2, CH3, C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5, and also phenyl.

[0085] A 1 and A 2 Very preferred wherein L has one of the meanings indicated above, and r represents 0, 1, 2, 3 or 4, in particular,

[0086] yes

[0087] The polymerizable group P is a group which is suitable for polymerization reactions (e.g. free radical or ionic chain polymerization, polyaddition or polycondensation) or for polymer-analogous transformation reactions (e.g. addition or condensation onto the polymer backbone). Particular preference is given to groups for chain polymerization, in particular those containing a C=C double bond or a -C≡C- triple bond, and groups which are suitable for polymerization under ring opening, such as oxetane or epoxy groups.

[0088] Preferred groups P are selected from

[0089] CH2=CW 1 -CO-O-, CH2=CW 1 -CO-, CH2=CW 2 -(O) k3 -、CW 1 =CH-CO-(O) k3 -、CW 1 =CH-CO-NH-, CH2=CW 1 -CO-NH-, CH3-CH=CH-O-, (CH2=CH)2CH-OCO-, (CH2=CH-CH2)2CH-OCO-, (CH2=CH)2CH-O-, (CH2=CH-CH2)2N-, (CH2=CH-CH2)2N-CO-, HO-CW 2 W 3 -、HS-CW 2 W 3 -、HW 2 N-、HO-CW 2 W 3 -NH-, CH2=CW 1 -CO-NH-, CH2=CH-(COO) k1 -Phe-(O)k2 -、CH2=CH-(CO) k1 -Phe-(O) k2 -, Phe-CH=CH-, HOOC-, OCN- and W 4 W 5 W 6 Si-, where W 1 represents H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH3, W 2 and W 3 each independently of one another represents H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W 4 , W 5 and W 6 each independently represents Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W 7 and W 8 Each independently represents H, Cl or an alkyl group having 1 to 5 C atoms, Phe represents 1,4-phenylene which is optionally substituted by one or more groups L other than P-Sp- as defined above, k1, k2 and k3 each independently represent 0 or 1, k3 preferably represents 1, and k4 represents an integer from 1 to 10.

[0090] Very preferred groups P are selected from

[0091] CH2=CW 1 -CO-O-, CH2=CW 1 -CO-, CH2=CW 2 -O-, CH2=CW 2 -、CW 1 =CH-CO-(O) k3 -、CW 1 =CH-CO-NH-, CH2=CW 1 -CO-NH-, (CH2=CH)2CH-OCO-, (CH2=CH-CH2)2CH-OCO-, (CH2=CH)2CH-O-, (CH2=CH-CH2)2N-, (CH2=CH-CH2)2N-CO-, CH2=CW 1 -CO-NH-, CH2=CH-(COO) k1 -Phe-(O) k2 -、CH2=CH-(CO) k1 -Phe-(O) k2 -, Phe-CH=CH- and W 4 W 5W 6 Si-, where W 1 represents H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH3, W 2 and W 3 each independently of one another represents H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W 4 , W 5 and W 6 each independently represents Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W 7 and W 8 Each independently represents H, Cl or an alkyl group having 1 to 5 C atoms, Phe represents 1,4-phenylene, k1, k2 and k3 each independently represent 0 or 1, k3 preferably represents 1, and k4 represents an integer of 1 to 10.

[0092] Very particularly preferred groups P are selected from the group consisting of CH2=CW 1 -CO-O-, especially CH2=CH-CO-O-, CH2=C(CH3)-CO-O- and CH2=CF-CO-O-, in addition CH2=CH-O-, (CH2=CH)2CH-O-CO-, (CH2=CH)2CH-O-,

[0093] Further preferred polymerizable groups P are selected from vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide, most preferably from acrylate and methacrylate.

[0094] If the spacer group Sp is not a single bond, it is preferably a spacer group of the formula Sp"-X", so that the corresponding group P-Sp- conforms to the formula R-Sp"-X"-, where

[0095] Sp" denotes a straight-chain or branched alkylene radical having 1 to 20, preferably 1 to 12 C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN, and wherein in addition, one or more non-adjacent CH2 groups may each independently of one another be substituted by -O-, -S-, -NH-, -N(R 0 )-、-Si(R 0 R 00 )-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -S-CO-, -CO-S-, -N(R 00 )-CO-O-、-O-CO-N(R 0 )-、-N(R 0 )-CO-N(R 00)-, -CH=CH- or -C≡C- are replaced in such a way that the O and / or S atoms are not directly connected to each other,

[0096] X" means -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CO-N(R 0 )-、-N(R 0 )-CO-、-N(R 0 )-CO-N(R 00 )-, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=N-, -N=CH-, -N=N-, -CH=CR 0 -、-CY 2 =CY 3 -, -C≡C-, -CH=CH-CO-O-, -O-CO-CH=CH- or a single bond,

[0097] R 0 and R 00 each independently of one another represents H or an alkyl group having 1 to 20 C atoms, and

[0098] Y 2 and Y 3 Each independently of one another represents H, F, Cl or CN.

[0099] X" is preferably -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR 0 -、-NR 0 -CO-、-NR 0 -CO-NR 00 - or single key.

[0100] Typical spacer groups Sp and -Sp"-X"- are, for example, -(CH2) p1 -、-(CH2) p1 -O-, -(CH2) p1 -O-CO-, -(CH2) p1 -CO-O-, -(CH2) p1 -O-CO-O-, -(CH2CH2O) q1 -CH2CH2-, -CH2CH2-S-CH2CH2-, -CH2CH2-NH-CH2CH2- or -(SiR 0 R 00 -O) p1 -, wherein p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R0 and R 00 has the meaning indicated above.

[0101] Particularly preferred groups Sp and -Sp"-X"- are -(CH2) p1 -、-(CH2) p1 -O-, -(CH2) p1 -O-CO-, -(CH2) p1 -CO-O-, -(CH2) p1 -O-CO-O-, wherein p1 and q1 have the meanings indicated above.

[0102] Particularly preferred radicals Sp" are in each case linear ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene, vinylene, propenylene and butenylene.

[0103] In a preferred embodiment of the invention, the compounds of formula P and its subformulae contain a spacer group Sp which is substituted by one or more polymerizable groups P, such that the group Sp-P corresponds to Sp(P) s , wherein s is ≥ 2 (branched polymerizable groups).

[0104] Preferred compounds of formula P according to this preferred embodiment are those wherein s is 2, ie compounds containing the group Sp(P)2. Very preferred compounds of formula P according to this preferred embodiment contain a group selected from the following formulae:

[0105] -X-alkyl-CHPP S1

[0106] -X-alkyl-CH((CH2) aa P)((CH2) bb P) S2

[0107] -XN((CH2) aa P)((CH2) bb P) S3

[0108] -X-alkyl-CHP-CH2-CH2P S4

[0109] -X-alkyl-C(CH2P)(CH2P)-C aa H 2aa+1 S5

[0110] -X-alkyl-CHP-CH2P S6

[0111] -X-alkyl-CPP-C aa H 2aa+1 S7

[0112] -X-alkyl-CHPCHP-C aa H 2aa+1 S8

[0113] wherein P is as defined in formula P,

[0114] Alkyl represents a single bond or a straight-chain or branched alkylene radical having 1 to 12 C atoms, which is unsubstituted or mono- or polysubstituted by F, Cl or CN, and in which one or more non-adjacent CH2 groups may each be replaced independently of one another by -C(R 0 )=C(R 0 )-、-C≡C-、-N(R 0 )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, wherein O and / or S atoms are not directly connected to each other, wherein R 0 has the meaning given above,

[0115] aa and bb each independently represent 0, 1, 2, 3, 4, 5 or 6,

[0116] X has one of the meanings indicated for X" and is preferably O, CO, SO2, O-CO-, CO-O or a single bond.

[0117] Preferred spacer groups Sp(P)2 are selected from the group consisting of formulae S1, S2 and S3.

[0118] Very preferred spacer groups Sp(P)2 are selected from the following sub-formulae:

[0119] -CHPP S1a

[0120] -O-CHPP S1b

[0121] -CH2-CHPP S1c

[0122] -OCH2-CHPP S1d

[0123] -CH(CH2-P)(CH2-P) S2a

[0124] -OCH(CH2-P)(CH2-P) S2b

[0125] -CH2-CH(CH2-P)(CH2-P) S2c

[0126] -OCH2-CH(CH2-P)(CH2-P) S2d

[0127] -CO-NH((CH2)2P)((CH2)2P) S3a

[0128] In the compounds of formula P and subformulae thereof as described above and below, P is preferably selected from vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide, most preferably from acrylate and methacrylate.

[0129] Further preferred are compounds of the formula P and subformulae thereof as described above and below, wherein all polymerizable groups P present in said compounds have the same meaning and very preferably denote acrylate or methacrylate, most preferably methacrylate.

[0130] In the compounds of formula P and subformulae thereof as described above and below, R preferably represents P-Sp-.

[0131] Further preferred are compounds of formula P and subformulae thereof as described above and below, wherein Sp represents a single bond or -(CH2) p1 -、-O-(CH2) p1 -、-O-CO-(CH2) p1 or -CO-O-(CH2) p1 , wherein p1 is 2, 3, 4, 5 or 6, and if Sp is -O-(CH2) p1 -、-O-CO-(CH2) p1 -or-CO-O-(CH2) p1 -, then the O atom or the CO group is connected to the benzene ring respectively.

[0132] Further preferred are compounds of the formula P and subformulae thereof as described above and below, wherein at least one group Sp is a single bond.

[0133] Further preferred are compounds of the formula P and its subformulae as described above and below, wherein at least one group Sp is not a single bond and is preferably selected from -(CH2) p1 -、-O-(CH2) p1 -、-O-CO-(CH2) p1 or -CO-O-(CH2) p1 , wherein p1 is 2, 3, 4, 5 or 6, and if Sp is -O-(CH2) p1 -、-O-CO-(CH2) p1 -or-CO-O-(CH2) p1 -, then the O atom or the CO group is connected to the benzene ring respectively.

[0134] A very preferred group in formula P is -A 1 -(ZA 2 ) z -Selected from the following formula:

[0135]

[0136]

[0137] wherein at least one phenyl ring is substituted by at least one group L, and the phenyl ring is optionally further substituted by one or more groups L or P-Sp-.

[0138] Preferred compounds of formula P and their subformulae are selected from the following preferred embodiments, including any combination thereof:

[0139] - all groups P in the compounds have the same meaning,

[0140] —-A 1 -(ZA 2 ) z - is selected from the group consisting of formulae A1, A2 and A5,

[0141] - said compound contains exactly two polymerizable groups (represented by the group P),

[0142] - said compound contains exactly three polymerizable groups (represented by the group P),

[0143] - P is selected from acrylates, methacrylates and oxetanes, very preferably acrylates or methacrylates,

[0144] - P is methacrylate,

[0145] - all groups Sp are single bonds,

[0146] - at least one of the groups Sp is a single bond and at least one of the groups Sp is not a single bond,

[0147] —Sp, when not a single bond, is -(CH2) p2 -、-(CH2) p2 -O-, -(CH2) p2 -CO-O-, -(CH2) p2 -O-CO-, wherein p2 is 2, 3, 4, 5 or 6, and the O atom or the CO group is respectively attached to the benzene ring,

[0148] —Sp is a single bond or represents -(CH2) p2 -、-(CH2) p2 -O-, -(CH2) p2-CO-O-, -(CH2) p2 -O-CO-, wherein p2 is 2, 3, 4, 5 or 6, and the O atom or the CO group is respectively attached to the benzene ring,

[0149] —R stands for P-Sp-,

[0150] - R does not represent or contain a polymerizable group,

[0151] —R does not represent or contain a polymerizable group, and represents 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 or L a Instead,

[0152] —L or L a represents F, Cl or CN,

[0153] —L is F.

[0154] In Formula IA, R 11 and R 12 preferably represents an alkyl or alkenyl or alkoxy radical having 1 to 7 C atoms, and R 12 Particular preference is given to alkoxy having 1 to 7 C atoms.

[0155] The compound of formula IA is preferably selected from the compounds of formulae IA-1 to IA-10:

[0156]

[0157]

[0158] Where R 12 represents an alkyl group having 1 to 7 C atoms, preferably ethyl, n-propyl or n-butyl.

[0159] Preferably, the medium according to the invention comprises one or more compounds selected from the group consisting of compounds of formulae IIA, IIB, IIC and IID,

[0160]

[0161]

[0162] in

[0163] R 2A , R 2B , R 2C and R 2Deach independently of one another represents H, alkyl or alkenyl with up to 15 C atoms, which is unsubstituted, monosubstituted by CN or CF3 or at least monosubstituted by halogen, wherein in addition one or more CH2 groups in these radicals may be replaced by -O-, -S-, -C≡C-, -CF2O-, -OCF2-, -OC-O- or -O-CO- are replaced in such a way that the O atoms are not directly connected to each other,

[0164] L 1 To L 4 each independently represents F, Cl, CF3 or CHF2,

[0165] Z 2 , Z 2B and Z 2D each independently represents a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF-, -CH=CHCH2O-,

[0166] p represents 0, 1 or 2,

[0167] q represents 0 or 1, and

[0168] v represents 1 to 6.

[0169] In a preferred embodiment of the invention, the medium comprises one or more compounds of formula IB

[0170]

[0171] in

[0172] R 11 and R 12 Each independently of one another represents H, alkyl or alkoxy having 1 to 15 C atoms, wherein in addition, one or more CH2 groups in these groups can each independently of one another be replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- is replaced in such a way that the O atoms are not directly connected to one another, and wherein in addition one or more H atoms may be replaced by halogen,

[0173] A 1 In each occurrence, they are expressed independently of each other

[0174] a) 1,4-cyclohexenyl or 1,4-cyclohexylene, in which one or two non-adjacent CH2 groups may be replaced by -O- or -S-,

[0175] b) 1,4-phenylene, in which one or both CH groups may be replaced by N,

[0176] c) a radical selected from the group consisting of piperidine-1,4-diyl, 1,4-bicyclo[2.2.2]octyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl and fluorene-2,7-diyl,

[0177] wherein the radicals a), b) and c) may be substituted singly or polysubstituted by halogen atoms,

[0178] a represents 0, 1 or 2, preferably 0 or 1, particularly preferably 0.

[0179] Z 1 represents, independently of one another at each occurrence, -CO-O-, -O-CO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -(CH2)4-, -CH=CH-CH2O-, -C2F4-, -CH2CF2-, -CF2CH2-, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C- or a single bond,

[0180] X 1 indicates S or O, and

[0181] L 11 and L 12 Each independently of one another represents F, Cl, CF3 or CHF2, preferably H or F, most preferably F,

[0182] The prerequisite is to exclude compounds of formula IA;

[0183] In the compounds of Formulae IA, IB and IC, R 11 and R 12 Preferably, each independently of one another represents a straight-chain alkyl group, in particular CH3, n-C2H5, n-C3H7, n-C4H9, n-C5H 11 、n-C6H 13 or n-C7H 15 , straight-chain alkoxy, especially CH3-O, n-C2H5-O, n-C3H7-O, n-C4H9-O, n-C5H 11 -O or n-C6H 13-O, furthermore alkenyl, in particular CH2=CH, CH3CH=CH, CH3CH=CHCH2 or CH3CH2CH=CH, branched alkoxy, in particular (CH3)2CH(CH2)3O, and alkenyloxy, in particular CH2=CHO, CH2=CH2CH2O, CH3CH=CHCH2O or CH3CH2CH=CHCH2O.

[0184] R 11 Particularly preferably represents a straight-chain alkyl radical having 1 to 7 C atoms, and R 12 Particularly preferably it denotes straight-chain alkoxy having 1 to 6 C atoms, in particular methoxy, ethoxy, propoxy, butoxy, pentyloxy or hexyloxy.

[0185] In formula IB, L 11 and L 12 Preferably both represent F.

[0186] The parameter "a" in formula IB preferably represents 1.

[0187] Preferred compounds of formula IB present in the medium are compounds of formulae IB-1 to IB-3, preferably compounds of formula IB-2,

[0188]

[0189] in

[0190] The radicals occurring have the meanings given above, and preferably

[0191] R 11 represents a straight chain alkyl group,

[0192] R 12 represents an alkoxy group, and

[0193] L 11 and L 12 Both mean F.

[0194] In a preferred embodiment, the medium comprises one or more compounds of formula IB selected from the group consisting of compounds of formula IB-O-1 to IB-O-3, preferably compounds of formula IB-O-2

[0195]

[0196] The radicals occurring therein have the meanings given above.

[0197] In another preferred embodiment, the medium comprises one or more compounds of formula IB selected from the group consisting of compounds of formulae IB-S-1 to IB-S-3, preferably compounds of formula IB-S-2,

[0198]

[0199] Therein the parameters stated have the meanings given above.

[0200] In a preferred embodiment of the invention, the medium comprises one or more compounds selected from the group consisting of compounds of formulae IB-O-1 to IB-O-3, and one or more compounds selected from the group consisting of compounds of formulae IB-S-1 to IB-S-3.

[0201] In a preferred embodiment, the medium comprises one or more compounds of formula IC

[0202]

[0203] The radicals occurring therein have the same meanings as given above under formula IB, and preferably

[0204] X 1 represents S,

[0205] R 11 and R 12 each independently of one another represents an alkyl, alkenyl or alkoxy group having up to 15 C atoms, more preferably one or both of them represent an alkoxy group, and

[0206] L 11 and L 12 Each preferably represents F.

[0207] In a preferred embodiment, the medium comprises one or more compounds of formula IC selected from the group consisting of compounds of formulae IC-O-1 to IC-O-10, preferably compounds of formula IC-O-6,

[0208]

[0209]

[0210] in

[0211] Alkyl and alkyl* each independently represent a straight-chain alkyl group having 1 to 6 C atoms, alkenyl and alkenyl* each independently represent a straight-chain alkenyl group having 2 to 6 C atoms, alkoxy and alkoxy* each independently represent a straight-chain alkoxy group having 1 to 6 C atoms, and L 1 and L 2 Each independently represents F or Cl.

[0212] In a further preferred embodiment, the medium comprises, instead of or in addition to one or more compounds selected from the group consisting of the compounds of the formulae IC-O-1 to IC-O-10, one or more compounds wherein X 1 A compound of formula IC wherein S is preferably selected from compounds of formulae IC-S-1 to IC-S-10, preferably a compound of formula IC-S-6, which has the same structure as the corresponding compounds of formulae IC-O-1 to IC-O-10 having the same number, differing only in the bridging atom (i.e. X 1 ) is a S atom replacing an O atom.

[0213] Compounds of the formula IA, IB and IC can be prepared, for example, as described in US 2005 / 0258399 or WO 02 / 055463 A1. Compounds of the formula IA are disclosed in DE 10 2015 004 271 A1.

[0214] Preferred embodiments of the liquid-crystalline media according to the invention are indicated below:

[0215] a) a liquid-crystalline medium which additionally comprises one or more compounds selected from the group consisting of compounds of the formulae IIA, IIB, IIC and IID,

[0216] In the compounds of Formula IIA, IIB and IID, Z 2 can have the same or different meanings. In the compounds of formula IIB, Z 2 and Z 2B can have the same or different meanings. In the compounds of formula IID, Z 2 and Z 2D can have the same or different meanings.

[0217] In the compounds of Formulae IIA, IIB, IIC and IID, R 2A , R 2B , R 2C and R 2D each preferably represents an alkyl radical having 1 to 6 C atoms, in particular CH3, C2H5, n-C3H7, n-C4H9, n-C5H 11 .

[0218] In the compounds of Formula IIA, IIB and IID, L 1 , L 2 , L 3 and L 4 Preferred expression L 1 =L 2 = F and L 3 =L 4 =F, and L 1 = F and L 2 =Cl,L1 =Cl and L 2 =F,L 3 = F and L 4 =Cl,L 3 =Cl and L 4 =F. Z in Formulas IIA and IIB 2 and Z 2 ' preferably each independently of one another represents a single bond and additionally a -C2H4- bridge.

[0219] If in Formula IIB, Z 2 =-C2H4- or -CH2O-, then Z 2B is preferably a single bond, or if Z 2B =-C2H4- or -CH2O-, then Z 2 A single bond is preferred.

[0220] In formula IID, Z 2D A single bond is preferred.

[0221] In the compounds of Formula IIA, IIB and IID, (O)C v H 2v+1 Preferred means OC v H 2v+1 In the compound of formula IIC, (O)C v H 2v+1 Preferred expression C v H 2v+1 .

[0222] In the compound of formula IIC, L 3 and L 4 Preferably each represents F.

[0223] Preferred compounds of formula IIA, IIB and IIC are indicated below:

[0224]

[0225]

[0226]

[0227]

[0228]

[0229]

[0230]

[0231]

[0232]

[0233]

[0234] in

[0235] Alkyl and alkyl* each independently represent a straight-chain alkyl radical having 1 to 6 C atoms,

[0236] alkenyl and alkenyl* each independently of one another represent straight-chain alkenyl having 2 to 6 C atoms, and

[0237] (O) represents -O- or a single bond.

[0238] Particularly preferred mixtures according to the invention comprise one or more compounds of the formulae IIA-2, IIA-8, IIA-14, IIA-26, II-28, IIA-33, IIA-39, IIA-45, IIA-46, IIA-47, IIA-50, IIB-2, IIB-11, IIB-16, IIC-1 and IID-4.

[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] Particularly preferred media according to the invention comprise at least one compound of the formula IIC-1,

[0241]

[0242] Where alkyl and alkyl* have the meanings indicated above, preferably the amount is >3% by weight, in particular >5% by weight and particularly preferably from 5 to 25% by weight.

[0243] b) a liquid-crystalline medium which additionally comprises one or more compounds of the formula III,

[0244]

[0245] in

[0246] R 31 and R 32 each independently of one another represents straight-chain alkyl, alkoxy, alkenyl, alkoxyalkyl or alkoxy having up to 12 C atoms, and

[0247] express

[0248] Z 3It represents a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -C4H8-, and -CF=CF-.

[0249] Preferred compounds of formula III are indicated below:

[0250]

[0251]

[0252] in

[0253] Alkyl and alkyl* each independently of one another denote a straight-chain alkyl radical having 1 to 6 C atoms.

[0254] The medium according to the invention preferably comprises at least one compound of the formula IIIa and / or formula IIIb.

[0255] The proportion of the compound of the formula III in the overall mixture is preferably at least 5% by weight.

[0256] c) a liquid-crystalline medium which additionally comprises a compound of the formula

[0257] and / or

[0258] and / or

[0259]

[0260] Preferably, their total amount is ≥5% by weight, in particular ≥10% by weight.

[0261] Preference is further given to mixtures according to the invention which comprise the following compound (acronym: CC-3-V1):

[0262]

[0263] The amount thereof is preferably 2 to 15% by weight.

[0264] Preferred mixtures comprise 5 to 60% by weight, preferably 10 to 55% by weight and in particular 20 to 50% by weight of a compound of the formula (acronym: CC-3-V)

[0265]

[0266] Further preferred is a mixture comprising

[0267] The compound of the following formula (acronym: CC-3-V)

[0268] and

[0269] The compound of the following formula (acronym: CC-3-V1)

[0270]

[0271] The total amount thereof is preferably in the range of 10 to 60% by weight.

[0272] d) a liquid-crystalline medium which additionally comprises one or more tetracyclic compounds of the formula

[0273]

[0274]

[0275] in

[0276] R 7-10 Each independently has the following characteristics for R in claim 5 2A One of the meanings indicated, and

[0277] w and x each independently represent 1 to 6.

[0278] Particular preference is given to mixtures comprising at least one compound of the formula V-9.

[0279] e) a liquid-crystalline medium which additionally comprises one or more compounds of the formulae Y-1 to Y-6,

[0280]

[0281] Where R 14 -R 19 Each independently represents an alkyl group or an alkoxy group having 1 to 6 C atoms; z and m each independently represent 1 to 6; and x represents 0, 1, 2 or 3.

[0282] The medium according to the invention particularly preferably comprises one or more compounds of the formulae Y-1 to Y-6, preferably in an amount of ≥5% by weight.

[0283] f) a liquid-crystalline medium which additionally comprises one or more fluorinated terphenyls of the formulae T-1 to T-21,

[0284]

[0285]

[0286]

[0287] in

[0288] R represents a straight-chain alkyl or alkoxy group having 1 to 6 C atoms, (O) represents -O- or a single bond, and m=0, 1, 2, 3, 4, 5 or 6, and n represents 0, 1, 2, 3 or 4.

[0289] R preferably represents methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy or pentyloxy.

[0290] The medium according to the invention preferably comprises the terphenyls of the formulae T-1 to T-21 in an amount of 2 to 30% by weight, in particular 5 to 20% by weight.

[0291] Particularly preferred are compounds of formula T-1, T-2, T-4, T-20 and T-21. In these compounds, R preferably represents alkyl, and alkoxy, each of which has 1 to 5 C atoms. In the compound of formula T-20, R preferably represents alkyl or alkenyl, in particular alkyl. In the compound of formula T-21, R preferably represents alkyl.

[0292] The terphenyls are preferably used in the mixtures according to the invention if the Δn value of the mixture is to be ≥ 0.1. Preferred mixtures comprise 2 to 20% by weight of one or more terphenyl compounds selected from the group consisting of compounds T-1 to T-21.

[0293] g) a liquid-crystalline medium which additionally comprises one or more biphenyls of the formulae B-1 to B-3,

[0294]

[0295] in

[0296] Alkyl and alkyl* each independently represent a straight-chain alkyl radical having 1 to 6 C atoms, and

[0297] Alkenyl and alkenyl* each independently of one another represent straight-chain alkenyl having 2 to 6 C atoms.

[0298] The proportion of biphenyls of the formulae B-1 to B-3 in the mixture as a whole is preferably at least 3% by weight, in particular ≥5% by weight.

[0299] Among the compounds of formulae B-1 to B-3, the compound of formula B-2 is particularly preferred.

[0300] Particularly preferred biphenyls are

[0301]

[0302]

[0303] Therein alkyl* denotes an alkyl radical having 1 to 6 C atoms. The medium according to the invention particularly preferably comprises one or more compounds of the formula B-1a and / or B-2c.

[0304] h) a liquid-crystalline medium comprising at least one compound of the formulae Z-1 to Z-7,

[0305]

[0306]

[0307] wherein R and alkyl have the meanings indicated above.

[0308] i) a liquid-crystalline medium which additionally comprises at least one compound of the formulae O-1 to O-18,

[0309]

[0310]

[0311]

[0312] Where R 1 and R 2 With respect to R 2A The meaning indicated. 1 and R 2 Preferably each independently of one another represents a straight-chain alkyl or alkenyl group.

[0313] Preferred media comprise one or more compounds of formula O-1, O-3, O-4, O-6, O-7, O-10, O-11, O-12, O-14, O-15, O-16 and / or O-17.

[0314] Particularly preferred media comprise one or more compounds selected from compounds of formula O-17,

[0315] The mixtures according to the invention very particularly preferably comprise compounds of the formulae O-10, O-12, O-16 and / or O-17, in particular in amounts of 5 to 30% by weight.

[0316] Preferred compounds of formula O-10 and O-17 are indicated below:

[0317]

[0318]

[0319] The medium according to the invention particularly preferably comprises a combination of a tricyclic compound of the formula O-10a and / or O-10b with one or more bicyclic compounds of the formulae O-17a to O-17d. The total proportion of the combination of the compound of the formula O-10a and / or O-10b with one or more compounds selected from the bicyclic compounds of the formulae O-17a to O-17d is 5 to 40% by weight, very particularly preferably 15 to 35% by weight.

[0320] Very particularly preferred mixtures comprise the compounds O-10a and O-17a:

[0321]

[0322] The compounds O-10a and O-17a are preferably present in the mixture in a concentration of 15 to 35% by weight, particularly preferably 15 to 25% by weight and especially preferably 18 to 22% by weight, based on the entire mixture.

[0323] Very particularly preferred mixtures comprise the compounds O-10b and O-17a:

[0324]

[0325] The compounds O-10b and O-17a are preferably present in the mixture in a concentration of 15 to 35% by weight, particularly preferably 15 to 25% by weight and especially preferably 18 to 22% by weight, based on the entire mixture.

[0326] Very particularly preferred mixtures comprise the following three compounds:

[0327]

[0328] The compounds O-10a, O-10b and O-17a are preferably present in the mixture in a concentration of 15 to 35% by weight, particularly preferably 15 to 25% by weight and especially preferably 18 to 22% by weight, based on the entire mixture.

[0329] Preferred mixtures contain at least one compound selected from the group consisting of:

[0330]

[0331] Where R 1 and R 2 Preferably, in compounds O-6, O-7 and O-17, R 1 represents an alkyl or alkenyl group having 1 to 6 or 2 to 6 C atoms, respectively, and R 2 represents an alkenyl group having 2 to 6 C atoms.

[0332] Preferred mixtures contain at least one compound of formula O-6a, O-6b, O-7a, O-7b, O-17e, O-17f, O-17g and O-17h:

[0333]

[0334] Here, alkyl represents an alkyl group having 1 to 6 C atoms.

[0335] The compounds of the formulae O-6, O-7 and O-17e-h are preferably present in the mixture according to the invention in an amount of 1 to 40% by weight, preferably 2 to 35% by weight and very particularly preferably 2 to 30% by weight.

[0336] j) Preferred liquid-crystalline media according to the invention comprise one or more substances containing tetrahydronaphthyl or naphthyl units, for example compounds of the formulae N-1 to N-5,

[0337]

[0338] Where R 1N and R 2N Each independently has a 2A The meanings indicated preferably represent straight-chain alkyl, straight-chain alkoxy or straight-chain alkenyl, and

[0339] Z 1 and Z 2 Each 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.

[0340] k) Preferred mixtures contain one or more compounds selected from the group consisting of difluorodibenzochroman compounds of formula BC, chromans of formula CR, fluorinated phenanthrenes of formula PH-1 and PH-2,

[0341]

[0342] in

[0343] R B1 , R B2 , R CR1 , R CR2 , R 1 , R 2 Each independently has R 2A c is 0, 1 or 2.1 and R 2 Preferably, independently of one another, they are alkyl or alkoxy radicals having 1 to 6 C atoms.

[0344] The mixtures according to the invention preferably comprise the compounds of the formula BC, CR, PH-1 and / or PH-2 in an amount of 3 to 20% by weight, in particular in an amount of 3 to 15% by weight.

[0345] Particularly preferred compounds of formula BC and CR are compounds BC-1 to BC-7 and CR-1 to CR-5,

[0346]

[0347]

[0348] in

[0349] Alkyl and alkyl* each independently represent a straight-chain alkyl radical having 1 to 6 C atoms, and

[0350] Alkenyl and alkenyl* each independently of one another represent straight-chain alkenyl having 2 to 6 C atoms.

[0351] Very particular preference is given to mixtures comprising one, two or three compounds of the formula BC-2.

[0352] 1) Preferred mixtures contain one or more indane compounds of the formula In,

[0353]

[0354] in

[0355] R 11 , R 12 , R 13 each independently of one another represents a straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl radical having 1 to 6 C atoms,

[0356] R 12 and R 13 Additionally represents halogen, preferably F,

[0357] express

[0358] i represents 0, 1 or 2.

[0359] Preferred compounds of formula In are compounds of formulae In-1 to In-16 indicated below:

[0360]

[0361]

[0362]

[0363] Compounds of the formulae In-1, In-2, In-3 and In-4 are particularly preferred.

[0364] The compounds of the formula In and subformulae In-1 to In-16 are preferably used in the mixtures 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.

[0365] m) Preferred mixtures additionally comprise one or more compounds of the formulae L-1 to L-5,

[0366]

[0367] in

[0368] R, R 1 and R 2 Each independently has the following formula IIA for R 2A The parameter s represents 1 or 2.

[0369] The compounds of the formulae L-1 to L-5 are preferably used in a concentration of 5 to 50% by weight, in particular 5 to 40% by weight and very particularly preferably 10 to 40% by weight.

[0370] Preferably, the medium according to the invention comprises a stabilizer chosen from compounds of formulae ST-1 to ST-18.

[0371]

[0372]

[0373]

[0374]

[0375] in

[0376] R ST represents H, alkyl or alkoxy having 1 to 15 C atoms, wherein in addition, one or more CH2 groups in these groups can each independently of one another be replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O-, -O-CO- are replaced in such a way that the O atoms are not directly connected to one another, and wherein in addition one or more H atoms may be replaced by halogen,

[0377] express

[0378] 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,

[0379] L 1 and L 2 each independently represents F, Cl, CF3 or CHF2,

[0380] p means 1 or 2,

[0381] q represents 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0382] Among the compounds of formula ST, the compounds of the formula

[0383]

[0384] wherein n=1, 2, 3, 4, 5, 6 or 7, preferably n=1 or 7

[0385]

[0386] wherein n=1, 2, 3, 4, 5, 6 or 7, preferably n=3

[0387]

[0388] wherein n=1, 2, 3, 4, 5, 6 or 7, preferably n=3

[0389]

[0390]

[0391] In the compounds of formulae ST-3a and ST-3b, n preferably represents 3. In the compounds of formula ST-2a, n preferably represents 7.

[0392] Very particularly preferred mixtures according to the invention comprise one or more stabilizers selected from compounds of the formulae ST-2a-1, ST-3a-1, ST-3b-1, ST-8-1, ST-9-1 and ST-12:

[0393]

[0394]

[0395] The compounds of the formulae ST-1 to ST-18 are preferably each present in an amount of 0.005 to 0.5% by weight, based on the liquid-crystal mixture according to the invention.

[0396] If the mixture according to the invention comprises two or more compounds selected from the compounds of the formulae ST-1 to ST-18, the concentration is correspondingly increased to 0.01 to 1% by weight, based on the mixture, in the case of two compounds.

[0397] However, the total proportion of compounds of the formulae ST-1 to ST-18, based on the mixture according to the invention, should not exceed 2% by weight.

[0398] Particularly preferred mixture concepts are indicated below: (the acronyms used are explained in Table A. n and m here each independently of one another denote 1 to 15, preferably 1 to 6).

[0399] The mixture according to the invention preferably comprises

[0400] one or more compounds of the formula IA selected from COB(S)-2-O2, COB(S)-2-O4 and COB(S)-4-O4, preferably in a total concentration in the range of 1% to 25% by weight, more preferably 5% to 15% by weight and particularly preferably 7% to 10% by weight;

[0401] and / or

[0402] one or more compounds of the formulae IA, IIA and IIC, preferably in a total concentration in the range of 25 to 65% by weight, more preferably 30 to 55% by weight, particularly preferably 40 to 50% by weight;

[0403] and / or

[0404] one or more compounds of the formulae IA and IIA and IID-4 and IIC, preferably in a total concentration in the range of 40% to 85% by weight, more preferably 50% to 70% by weight, particularly preferably 55% to 65% by weight;

[0405] and / or

[0406] one or more compounds of the formulae IA, IIB and IIC, preferably in a total concentration in the range of 15 to 45% by weight, more preferably 20 to 40% by weight, particularly preferably 25 to 35% by weight;

[0407] and / or

[0408] one or more compounds of the formulae IA and IIB and IIC and IID-4, preferably in a total concentration in the range of 30% to 60% by weight, more preferably 35% to 55% by weight, particularly preferably 40% to 50% by weight;

[0409] and / or

[0410] one or more compounds of the formula IA and IC, preferably in a total concentration in the range from 10% to 20% by weight, particularly preferably from 12% to 18% by weight;

[0411] and / or

[0412] - one or more compounds of the formulae IA, IC and IIA, preferably in a total concentration ranging from 20% to 60% by weight, preferably from 40% to 50% by weight;

[0413] and / or

[0414] - one or more compounds CY-n-Om, in particular CY-3-O4, CY-5-O4 and / or CY-3-O2, the total concentration of which is preferably in the range of 5% to 20% by weight, preferably 10% to 17% by weight;

[0415] and / or

[0416] CPY-n-Om, in particular CPY-2-O2, CPY-3-O2 and / or CPY-5-O2, preferably in a concentration of >5% by weight, in particular 10 to 30% by weight, based on the entire mixture,

[0417] and / or

[0418] 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 >5% by weight, in particular from 10 to 30% by weight, based on the entire mixture;

[0419] and / or

[0420] - CLY-n-Om, preferably CLY-2-O4, CLY-3-O2 and / or CLY-3-O3, preferably in a concentration of >5% by weight, in particular 10 to 30% by weight, very preferably 15 to 20% by weight, based on the entire mixture;

[0421] Preference is further given to mixtures according to the invention which comprise the following compounds:

[0422] (n and m each independently represent 1 to 6.)

[0423] - one or more compounds of formula IB, wherein L 11 =L 12 =F, R 1 = alkyl and R 1* = alkoxy;

[0424] - compounds of the formula IB, preferably compounds of the formulae IB-1 to IB-3, i.e. compounds of the formulae IB-O-1 to IB-O-3 and / or IB-S-1 to IB-S-3, in particular compounds of LB-3-O4 and / or LB(S)-4-O3, in a concentration in the range from 1 to 20% by weight, more preferably from 2 to 15% by weight, particularly preferably from 3 to 12% by weight and very particularly preferably from 4 to 11% by weight;

[0425] - CPY-n-Om and CY-n-Om, preferably in a concentration of 10 to 80% by weight, based on the entire mixture,

[0426] and / or

[0427] CPY-n-Om and PY-n-Om, preferably CPY-2-O2 and / or CPY-3-O2 and PY-3-O2, preferably in a concentration of 10 to 45% by weight, based on the entire mixture,

[0428] and / or

[0429] - CPY-n-Om and CLY-n-Om, preferably in a concentration of 10 to 80% by weight, based on the entire mixture,

[0430] and / or

[0431] - CCVC-nV, preferably CCVC-3-V, preferably in a concentration of 2 to 10% by weight, based on the entire mixture,

[0432] and / or

[0433] - CC-VV, preferably in a concentration of 5 to 50% by weight, based on the entire mixture.

[0434] In a particularly preferred embodiment of the present invention, the medium contains one or more compounds of the formula B-nO-Om and / or B(S)-nO-Om, in particular the compound B(S)-2O-O5, whose concentration is preferably in the range of 2 to 8 weight %, and the compound CC-3-V, whose concentration is in the range of 25 to 40 weight %, and optionally the compound CC-3-V1, whose concentration is in the range of 1 to 10 weight %, preferably 2 to 5 weight %.

[0435] The invention further relates to an electro-optical display with active-matrix addressing, characterized in that it contains a liquid-crystalline medium according to claim 1 as dielectric, and in which the display is a VA, SA-VA, IPS, U-IPS, FFS, UB-FFS, SA-FFS, PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS, PS-posi-VA, PS-TN, polymer-stabilized SA-VA or polymer-stabilized SA-FFS display.

[0436] Advantageously, the liquid-crystalline media according to the invention preferably have a nematic phase from ≤-20°C to ≥70°C, particularly preferably from ≤-30°C to ≥80°C, very particularly preferably from ≤-40°C to ≥90°C.

[0437] The medium according to the invention has a clearing temperature of 80° C. or higher, preferably 85° C. or higher.

[0438] Here, the expression "having a nematic phase" means, on the one hand, that no smectic phase and no crystallization are observed after cooling for a certain time at a given temperature, and, on the other hand, that no clearing occurs when heating from the nematic phase. The studies at low temperatures are carried out in a flow viscometer at the corresponding temperature and checked by storage for at least 100 hours in a test cell with a layer thickness corresponding to the electro-optical application. If the storage stability at a temperature of -20°C in a corresponding test cell is 1000 hours or more, the medium is said to be stable at this temperature. At temperatures of -30°C and -40°C, the corresponding times are 500 hours and 250 hours, respectively. At high temperatures, the clearing point is measured in a capillary by conventional methods.

[0439] The liquid crystal mixture preferably has a nematic phase range of at least 60 K and a nematic phase range of at most 30 mm at 20° C. 2 ·s -1 The flow viscosity ν 20 .

[0440] The value of the birefringence Δn in the liquid-crystal mixture is generally between 0.07 and 0.16, preferably between 0.08 and 0.13 and very preferably between 0.09 and 0.12.

[0441] In a preferred embodiment of the invention, the medium has a birefringence in the range of 0.100 to 0.115, preferably 0.105 to 0.112.

[0442] In another preferred embodiment, the medium according to the invention has a birefringence of 0.100 or less, in the range of 0.070 to 0.098, preferably 0.085 to 0.095.

[0443] The liquid crystal mixture according to the invention has a Δε, where Δε denotes the dielectric anisotropy, of -0.5 to -8.0, in particular -2.5 to -6.0. The rotational viscosity γ1 at 20° C. is preferably ≤150 mPa·s, in particular ≤120 mPa·s.

[0444] In a preferred embodiment, the rotational viscosity γ1 at 20° C. is ≤100 mPa·s, in particular ≤95 mPa·s.

[0445] The liquid-crystal media according to the invention have relatively low values ​​for the threshold voltage (V0). They are preferably in the range from 1.7 V to 3.0 V, particularly preferably ≤2.5 V and very particularly preferably ≤2.3 V.

[0446] For the present invention, unless explicitly stated otherwise, the term "threshold voltage" relates to the capacitance threshold (V0) also known as the Freedericksz threshold.

[0447] Furthermore, the liquid-crystalline media according to the invention have high voltage holding ratio values ​​in liquid-crystal cells.

[0448] Typically, liquid crystal media having a low addressing voltage or threshold voltage exhibit lower voltage holding ratios than those having a higher addressing voltage or threshold voltage, and vice versa.

[0449] 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 compounds with -1.5≤Δε≤1.5, and the term "dielectrically negative compounds" refers to those compounds with Δε<-1.5. The dielectric anisotropy of the compounds is determined here by dissolving 10% of the compounds in a liquid-crystal host and determining the capacitance of the resulting mixture at 1 kHz in at least one test liquid-crystal cell with a layer thickness of 20 μm in each case, both with homeotropic surface alignment and with planar surface alignment. The measuring voltage is typically 0.5 V to 1.0 V, but is always below the capacitance threshold of the respective liquid-crystal mixture under investigation.

[0450] All temperature values ​​indicated for the present invention are in °C.

[0451] The mixtures according to the invention are suitable for all VA-TFT applications, such as VAN, MVA, (S)-PVA, ASV, PSA (polymer-stabilized VA) and PS-VA (polymer-stabilized VA). They are further suitable for IPS (in-plane switching) and FFS (fringe field switching) applications with negative Δε.

[0452] The nematic liquid-crystal mixtures in the displays according to the invention generally comprise two components A and B, which themselves consist of one or more individual compounds.

[0453] Component A has a significantly negative dielectric anisotropy and imparts to the nematic phase a dielectric anisotropy of ≤-0.5. In addition to one or more compounds of formula I, it preferably comprises compounds of formula IIA, IIB and / or IIC and, in addition, one or more compounds of formula O-17.

[0454] The proportion of component A is preferably between 45 and 100% by weight, in particular between 60 and 100% by weight.

[0455] For component A, preference is given to selecting one (or more) individual compounds having a Δε value of ≤−0.8. The smaller the proportion A in the overall mixture, the more negative this value must be.

[0456] Component B has significant nematogeneity and a particle size of no more than 30 mm at 20°C. 2 ·s -1 , preferably no more than 25mm 2 ·s -1 The flow viscosity.

[0457] A large number of suitable materials are known to the person skilled in the art from the literature. Compounds of the formula O-17 are particularly preferred.

[0458] Particularly preferred individual compounds in component B are those having a molecular weight of not more than 18 mm at 20°C. 2 ·s -1 , preferably no more than 12mm 2 ·s -1 Very low viscosity nematic liquid crystal with a flow viscosity of .

[0459] Component B is monotropically or enantiotropically nematic, does not have a smectic phase, and is capable of preventing the appearance of a smectic phase in the liquid crystal mixture at low to very low temperatures. For example, if various highly nematic materials are added to a smectic liquid crystal mixture, the nematicity of these materials can be compared by the degree of suppression of the smectic phase achieved.

[0460] The mixture may optionally further comprise a component C comprising compounds having a dielectric anisotropy of Δε≥1.5. These so-called positive compounds are generally present in mixtures of negative dielectric anisotropy in an amount of ≤20% by weight, based on the overall mixture.

[0461] In addition to one or more compounds of formula I, the phase preferably comprises 4 to 15, in particular 5 to 12, and particularly preferably <10 compounds of formula IIA, IIB and / or IIC, and optionally one or more compounds of formula O-17.

[0462] Besides the compound of formula IB and the compound of formula IIA, IIB and / or IIC and optionally O-17, further constituents may also be present, for example in amounts of up to 45% by weight, but preferably up to 35% by weight and in particular up to 10% by weight of the overall mixture.

[0463] The further components are preferably selected from nematic or nematic substances, in particular known substances, which are selected from the following classes: azoxybenzene, benzalidine, biphenyl, terphenyl, phenyl benzoate or cyclohexyl benzoate, phenyl cyclohexanecarboxylate or cyclohexyl cyclohexanecarboxylate, phenylcyclohexane, cyclohexylbiphenyl, cyclohexylcyclohexane, cyclohexylnaphthalene, 1,4-dicyclohexylbiphenyl or cyclohexylpyrimidine, phenyl- or cyclohexyldiphenylamine Alkane, optionally halogenated Benzyl phenyl ether, tolan and substituted cinnamate.

[0464] The most important compounds suitable as constituents of this type of liquid-crystalline phase can be characterized by the formula IV

[0465] R 20 -LGER 21 IV

[0466] wherein L and E each represent a carbocyclic or heterocyclic ring system, the system being derived from a radical formed by 1,4-disubstituted benzene and cyclohexane rings, 4,4'-disubstituted biphenyls, phenylcyclohexane and cyclohexylcyclohexane systems, 2,5-disubstituted pyrimidines and 1,3-disubstituted alkane rings, 2,6-disubstituted naphthalenes, di- and tetrahydronaphthalenes, quinazolines and tetrahydroquinazolines,

[0467] G represents -CH=CH-, -N(O)=N-, -CH=CQ-, -CH=N(O)-, -C≡C-, -CH2-CH2-, -CO-O-, -CH2-O-, -CO-S-, -CH2-S-, -CH=N-, -COO-Phe-COO-, -CF2O-, -CF=CF-, -OCF2-, -OCH2-, -(CH2)4-, -(CH2)3O,

[0468] or CC single key,

[0469] Q represents halogen, preferably chlorine, or -CN, and

[0470] R 20 and R 21Each represents 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.

[0471] In most of these compounds, R 20 and R 21 are different from one another, one of these groups being generally an alkyl or alkoxy group. Other variants of the proposed substituents are also common. Many such substances or also mixtures thereof are commercially available. All these substances can be prepared by methods known from the literature.

[0472] It is self-evident to the person skilled in the art that the VA, IPS or FFS mixtures according to the invention may also comprise compounds in which, for example, H, N, O, Cl and F have been replaced by the corresponding isotopes.

[0473] The compound of formula P is optionally added to the mixture according to the invention in a concentration of preferably 0.01 to 5% by weight, particularly preferably 0.2 to 2% by weight, based on the mixture. These mixtures may optionally also contain an initiator, such as those described, for example, in US Pat. No. 6,781,665. The initiator, for example Irganox-1076 from BASF, is preferably added to the mixture containing the polymerizable compound in an amount of 0 to 1%. This type of mixture can be used for the so-called polymer-stabilized VA mode (PS-VA) or PSA (polymer-stabilized VA), in which the polymerization of the reactive mesogen is intended to occur in the liquid crystal mixture after filling the display panel. A prerequisite for this is that the liquid crystal compound of the LC host does not react under the polymerization conditions of the reactive mesogen, i.e., usually when exposed to UV in the wavelength range of 320 to 360 nm. Liquid crystal compounds containing alkenyl side chains, such as CC-3-V, do not show a reaction under the polymerization conditions (UV polymerization) for the RM, and therefore such compounds are not considered RMs herein.

[0474] Preferred compounds of formula P are selected from the following:

[0475]

[0476]

[0477]

[0478]

[0479]

[0480]

[0481] The various groups have the following meanings:

[0482] P 1 , P 2 and P 3 each independently of one another represents an acrylate or methacrylate group,

[0483] Sp 1 、Sp 2 and Sp 3 each independently of one another represents a single bond or a spacer having one of the meanings indicated above and below for Sp, and particularly preferably represents -(CH2) p1 -、-(CH2) p1 -O-, -(CH2) p1 -CO-O-, -(CH2) p1 -O-CO- or -(CH2) p1 -O-CO-O-, wherein p1 is an integer from 1 to 12, wherein in addition, the group P 1 -Sp 1 -、P 1 -Sp 2 - and P 3 -Sp 3 -One or more of them can represent R aa , provided that the group P 1 -Sp 1 -、P 2 -Sp 2 and P 3 -Sp 3 -At least one of them is not R aa ,

[0484] R aa represents H, F, Cl, CN or a straight-chain or branched alkyl radical having 1 to 25 C atoms, wherein in addition, one or more non-adjacent CH2 groups may each be replaced independently of one another by C(R 0 )=C(R 00 )-、-C≡C-、-N(R 0 )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, in such a way that the O and / or S atoms are not directly connected to each other, and wherein in addition, one or more H atoms may be replaced by F, Cl, CN or P 1 -Sp 1- alternatively, particularly preferably with a straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy radical having 1 to 12 C atoms (wherein the alkenyl and alkynyl radicals have at least two C atoms and the branched radicals have at least three C atoms),

[0485] R 0 , R 00 each independently of one another and identically or differently on each occurrence represent H or alkyl having 1 to 12 C atoms,

[0486] R y and R z each independently represents H, F, CH3 or CF3,

[0487] X 1 , X 2 and X 3 each independently represents -CO-O-, -O-CO- or a single bond,

[0488] Z 1 Indicates -O-, -CO-, -C(R y R z )- or -CF2CF2-,

[0489] Z 2 and Z 3 Each independently represents -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CF2O-, -OCF2- or -(CH2) n -, where n is 2, 3, or 4,

[0490] L, identically or differently on each occurrence, represents F, Cl, CN or linear or branched, optionally mono- or polyfluorinated, alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy radicals having 1 to 12 C atoms, preferably F,

[0491] L' and L" each independently represent H, F or Cl,

[0492] r represents 0, 1, 2, 3 or 4,

[0493] s represents 0, 1, 2, or 3,

[0494] t represents 0, 1 or 2,

[0495] x represents 0 or 1.

[0496] Particularly preferred compounds of formula P are compounds of formula P-2, P-13, P-17, P-22, P-23, P-24 and P-30.

[0497] Further preferred are the trireactive compounds P-17 to P-31, in particular P-17, P-18, P-19, P-22, P-23, P-24, P-25, P-26, P-30 and P-31.

[0498] In the compounds of formulae P-1 to P-31,

[0499] Group Preferably

[0500] in which L has, identically or differently on each occurrence, one of the meanings given above and below and is preferably F, Cl, CN, NO2, CH3, C2H5, C(CH3)3, CH(CH3)2, CH2CH(CH3)C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5 or P-Sp-, very preferably F, Cl, CN, CH3, C2H5, OCH3, COCH3, OCF3 or P-Sp-, more preferably F, Cl, CH3, OCH3, COCH3 or OCF3 and in particular F or CH3.

[0501] The mixture according to the present invention may further comprise conventional additives, such as stabilizers, antioxidants, UV absorbers, nanoparticles, microparticles and the like.

[0502] The structure of the liquid-crystal display according to the invention corresponds to the customary geometry, as described, for example, in EP-A 0 240 379.

[0503] The following examples are intended to illustrate the invention without limiting it. Above and below, percentage data indicate percentages by weight; all temperatures are given in degrees Celsius.

[0504] Throughout this patent application, 1,4-cyclohexylene rings and 1,4-phenylene rings are depicted as follows:

[0505]

[0506] The cyclohexylene ring is a trans-1,4-cyclohexylene ring unless specifically mentioned otherwise.

[0507] Throughout the present patent application and in the examples, the structures of the liquid crystal compounds are indicated by means of acronyms. Unless otherwise indicated, the conversion into chemical formulae is carried out according to Tables 1 to 3. All radicals C n H 2n+1 , C m H2m+1 and C m' H 2m'+1 or C n H 2n and C m H 2m is a straight-chain alkyl or alkylene radical having in each case n, m, m' or z C atoms. n, m, m', z each independently of one another represent 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, preferably 1, 2, 3, 4, 5 or 6. In Table 1, the ring elements of the corresponding compounds are coded, in Table 2, the bridging members are listed, and in Table 3, the meaning of the symbols for the left-hand or right-hand side chains of the compounds is indicated.

[0508] Table 1: Ring elements

[0509]

[0510]

[0511]

[0512] Table 2: Bridge elements

[0513]

[0514] Table 3: Sidechains

[0515]

[0516]

[0517] In addition to one or more compounds of the formula I, the mixtures according to the invention preferably also comprise one or more compounds which are mentioned in Table A below.

[0518] Table A

[0519] The following abbreviations are used:

[0520] (n, m, m', z: each independently, 1, 2, 3, 4, 5 or 6; (O) C m H 2m+1 Meaning OC m H 2m+1 or C m H 2m+1 )

[0521]

[0522]

[0523]

[0524]

[0525]

[0526]

[0527]

[0528]

[0529]

[0530]

[0531]

[0532]

[0533]

[0534]

[0535]

[0536]

[0537]

[0538]

[0539]

[0540]

[0541] The liquid crystal mixtures which can be used according to the invention are prepared in a manner conventional per se. Usually, the desired amount of the component used in smaller amounts is dissolved in the component constituting the main constituent, advantageously at elevated temperature. It is also possible to mix solutions of the components in organic solvents (for example in acetone, chloroform or methanol) and to remove the solvent again, for example by distillation, after thorough mixing.

[0542] With the aid of suitable additives, the liquid-crystalline phases according to the invention can be modified in such a way that they can be used in any type of LCD display known to date, for example ECB, VAN, IPS, GH or ASM-VA.

[0543] The dielectric may also contain other additives known to the person skilled in the art and described in the literature, such as UV absorbers, antioxidants, nanoparticles and free radical scavengers. For example, 0 to 15% of pleochroic dyes, stabilizers such as phenols, HALS (hindered amine light stabilizers) or chiral dopants may be added. Suitable stabilizers for the mixtures according to the invention are in particular those listed in Table C.

[0544] For example, 0 to 15% of pleochroic dyes can be added, and in addition, to improve the conductivity, conductive salts can be added, preferably 4-hexyloxybenzoic acid ethyldimethyl dodecyl ammonium, tetraphenyl boranate tetrabutyl ammonium or complex salts of crown ethers (see, for example, Haller et al., Mol. Cryst. Liq. Cryst., 1996). 24 Volume 249-258 (1973), or substances can be added to modify the dielectric anisotropy, viscosity and / or orientation of the nematic phase. Substances of this type are described, for example, in DE-A 22 09 127, 22 40 864, 23 21 632, 23 38 281, 24 50 088, 26 37 430 and 28 53 728.

[0545] Table B

[0546] Table B indicates possible dopants which can be added to the mixture according to the invention. If the mixture comprises a dopant, it is added in an amount of 0.01 to 4% by weight, preferably 0.01 to 3% by weight.

[0547]

[0548]

[0549] The mixture according to the invention comprises at least one stabilizer from Table C given below.

[0550] Table C

[0551] It is indicated below that stabilizers can be added to the mixture according to the invention, for example, in amounts of 0 to 10% by weight, preferably 0.001 to 5% by weight and in particular 0.001 to 1% by weight.

[0552]

[0553]

[0554]

[0555]

[0556]

[0557]

[0558] Table D

[0559] Table D shows exemplary reactive mesogenic compounds of the formula P which can be used in the LC media according to the invention.

[0560]

[0561]

[0562]

[0563]

[0564]

[0565]

[0566]

[0567]

[0568]

[0569]

[0570]

[0571]

[0572]

[0573]

[0574]

[0575]

[0576]

[0577]

[0578]

[0579]

[0580]

[0581]

[0582]

[0583] In a preferred embodiment, the mixture according to the invention comprises one or more polymerizable compounds preferably selected from the group consisting of polymerizable compounds of formulae RM-1 to RM-131. Of these compounds, compounds RM-1, RM-4, RM-8, RM-17, RM-19, RM-35, RM-37, RM-43, RM-47, RM-49, RM-51, RM-59, RM-69, RM-71, RM-83, RM-97, RM-98, RM-104, RM-112, RM-115, RM-116 and RM-128 are particularly preferred. DETAILED DESCRIPTION

[0584] Example:

[0585] The following examples are intended to illustrate the invention without limiting it. In the examples, mp represents the melting point, and C represents the clearing point of the liquid crystal substance in degrees Celsius; the boiling point is represented by mp. In addition: C represents the crystalline solid state, S represents the smectic phase (the index represents the phase type), N represents the nematic state, Ch represents the cholesteric phase, I represents the isotropic phase, T represents the crystalline solid state, and C represents the crystalline solid state. g Indicates the glass transition temperature. The number between the two symbols indicates the transition temperature in degrees Celsius.

[0586] The host mixture used for determining the optical anisotropy Δn of the compounds of formula IB was the commercial mixture ZLI-4792 (Merck KGaA). The dielectric anisotropy Δε was determined using the commercial mixture ZLI-2857. The physical data for the compounds to be investigated were obtained from the change in the dielectric constant of the host mixture after adding the compound to be investigated and extrapolated to 100% of the compound used. Typically, depending on the solubility, 10% of the compound to be investigated was dissolved in the host mixture.

[0587] Unless stated otherwise, parts or percentages are parts or percentages by weight.

[0588] Above and below:

[0589] V o represents the threshold voltage at 20°C, capacitance [V],

[0590] n e represents the extraordinary refractive index at 20°C and 589nm,

[0591] no represents the ordinary refractive index at 20°C and 589nm,

[0592] △n represents the optical anisotropy at 20°C and 589nm,

[0593] ε ⊥ represents the dielectric constant perpendicular to the direction of the direction loss at 20°C and 1kHz,

[0594] ε || represents the dielectric constant parallel to the direction of the loss at 20°C and 1kHz,

[0595] △ε represents the dielectric anisotropy at 20°C and 1kHz,

[0596] cl.p.,T(N,I) represents the clearing point [℃],

[0597] γ1 represents the rotational viscosity [mPa·s] measured at 20°C, which is determined by the rotation method in a magnetic field,

[0598] K1 represents the elastic constant at 20°C, “slope” deformation [pN],

[0599] K2 represents the elastic constant at 20°C, "torsion" deformation [pN],

[0600] K3 represents the elastic constant at 20°C, the “bending” deformation [pN], and

[0601] LTS stands for Low Temperature Stability (Nematic Phase), which is determined in a test cell or in bulk, as explicitly stated.

[0602] Unless expressly stated otherwise, all values ​​indicated in this application are indicated in degrees Celsius (° C.) for temperatures, e.g., melting point T(C,N), transition point T(S,N) from smectic (S) to nematic (N) phase and clearing point T(N,I) or cl.p. Mp denotes melting point. In addition, Tg=glassy state, C=crystalline state, N=nematic phase, S=smectic phase and I=isotropic phase. The numbers between these symbols represent transition temperatures.

[0603] Unless otherwise expressly stated, the term "threshold voltage" used in the present invention relates to the capacitive threshold (V0) also known as the Freedericksz threshold. In an embodiment, as is generally common, the optical threshold may also be the value for 10% relative contrast (V 10 ) pointed out.

[0604] The display used to measure the capacitance threshold voltage consisted of two plane-parallel glass outer plates separated by 20 μm, each with an electrode layer on the inside and an unrubbed polyimide alignment layer on top, which resulted in homeotropic edge alignment of the liquid crystal molecules.

[0605] The display or test liquid crystal cell used to measure the tilt angle consists of two plane-parallel glass outer plates separated by 4 μm, each having an electrode layer on the inside and a polyimide alignment layer on top, wherein the two polyimide layers are rubbed antiparallel to each other and result in homeotropic edge alignment of the liquid crystal molecules.

[0606] Unless otherwise indicated, the VHR was measured in a commercially available instrument model 6254 from TOYO Corporation, Japan, at 20°C (VHR 20 ) and after 5 minutes in a 100°C oven (VHR 100 The voltages used have frequencies in the range 1 Hz to 60 Hz, unless more precisely indicated.

[0607] The accuracy of the VHR measurement depends on the corresponding value of the VHR. The accuracy decreases with decreasing values. The deviations commonly observed when values ​​are within various magnitude ranges are compiled in the following table in order of their magnitude.

[0608]

[0609] The stability to UV irradiation was investigated in a commercial instrument "Suntest CPS" from Heraeus, Germany. The sealed test cells were irradiated for 30 minutes to 2.0 hours, without additional heating unless expressly stated. The irradiation power in the wavelength range of 300 nm to 800 nm was 765 W / m 2 V. To simulate the so-called window glass mode, a UV "cut-off" filter with a cut-off wavelength of 310 nm was used. In each series of experiments, at least four test cells were investigated for each condition, and the respective result is indicated as the average of the corresponding individual measured values.

[0610] The reduction in voltage holding ratio (ΔVHR) caused by exposure, for example, to UV radiation or by LCD backlighting is generally determined according to the following equation (1):

[0611] △VHR(t)=VHR(t)-VHR(t=0) (1).

[0612] To investigate the low temperature stability (LTS), i.e. the stability of the LC mixture in bulk to spontaneous crystallization of the individual components at low temperatures or the appearance of a smectic phase, several sealed bottles, each containing about 1 g of the material, were stored at one or more given temperatures (typically -10°C, -20°C, -30°C and / or -40°C) and periodically visually inspected for phase transitions. As soon as the first of the samples showed a change at a given temperature, the time was recorded. The time until the last inspection, at which no change was observed, was recorded as the respective LTS.

[0613] The ion density (from which the resistivity is calculated) is measured using a commercially available LC Material Characteristics Measurement System Model 6254 from Toyo Corporation, Japan, using a VHR test cell with AL16301 polyimide (JSR Corp., Japan) having a cell gap of 3.2 μm. The measurements are performed after storage in an oven at 60° C. or 100° C. for 5 minutes.

[0614] The so-called "HTP" denotes the helical twisting power (in μm) of the photoactive or chiral substance in the LC medium. Unless otherwise stated, the HTP is measured in the commercially available nematic LC host mixture MLD-6260 (Merck KGaA) at a temperature of 20°C.

[0615] Unless otherwise expressly stated, all concentrations in the present application are indicated as weight percent and relate to the corresponding entire mixture, which includes all solid or liquid crystal components, without solvent. All physical properties are determined according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals", November 1997, Merck KGaA, Germany, and apply to a temperature of 20° C., unless otherwise expressly stated.

[0616] The following examples of mixtures with negative dielectric anisotropy are particularly suitable for liquid crystal displays having at least one planar alignment layer, such as IPS and FFS displays, in particular UB-FFS (=Ultra Bright FFS), and for VA displays.

[0617] Mixture Examples and Comparative Examples

[0618] Prepared as follows Comparative mixture C1 :

[0619]

[0620] Prepared as follows Mixture M1 :

[0621]

[0622] Prepared as follows Mixture M2 :

[0623]

[0624]

[0625] Prepared as follows Mixture M3 :

[0626]

[0627] Prepared as follows Mixture M4 :

[0628]

[0629] Prepared as follows Mixture M5 :

[0630]

[0631]

[0632] Prepared as follows Mixture M6 :

[0633]

[0634] Prepared as follows Mixture M7 :

[0635]

[0636] The VHR of mixtures C1 and M1 to M6 have been measured as shown in the table below (VHR test cell with UV-PI for planar alignment, cell gap 4.0 μm, at 1 V, 1 Hz, 60° C.). The values ​​were measured immediately after filling the test cell.

[0637] mixture C1 M1 M2 M3 M4 M5 M6 M7 VHR [%] 95.5 96.2 95.9 96.3 95.8 95.9 96.5 96.5

[0638] Surprisingly, the use of compounds of the formula IA in the media according to the invention leads to liquid-crystal mixtures having a VHR that is at least as high as the reference mixture C1. At the same time, the media according to the invention exhibit a lower rotational viscosity than C1. Thus, media with improved response times can be achieved without negatively affecting reliability.

[0639] Prepared as follows Mixture M8 :

[0640]

[0641] Medium M8 is distinguished by a particularly low rotational viscosity, which enables the realization of LC displays having surprisingly short switching times.

[0642] Mixture M9

[0643]

[0644] Mixture M10

[0645] Mixture M10 consists of 99.96% of mixture M9 and 0.04% of compound ST-3a-1 indicated above.

[0646] Mixture M11

[0647]

[0648] Mixture M12

[0649] The mixture M12 consisted of 99.965% of the mixture M11 and 0.035% of the compound ST-3a-1 indicated above.

[0650] Mixture M13

[0651]

[0652]

[0653] Mixture M14

[0654] Mixture M14 consists of 99.965% of mixture M13 and 0.035% of compound ST-3a-1 indicated above.

[0655] Mixture M15

[0656]

[0657] Mixture M16

[0658] Mixture M16 consists of 99.965% of mixture M15 and 0.035% of compound ST-3a-1 indicated above.

[0659] Mixture M17

[0660]

[0661] Mixture M18

[0662]

[0663] Mixture M19

[0664]

[0665]

[0666] Mixture M20

[0667]

[0668] Mixture M21

[0669]

[0670] Mixture M22

[0671]

[0672]

[0673] Mixture M23

[0674]

[0675] Mixture M24

[0676]

[0677] Mixture M25

[0678]

[0679]

[0680] Mixture M26

[0681]

[0682] Mixture M27

[0683]

[0684]

[0685] Mixture M28

[0686]

[0687] Mixture M29

[0688] Mixture M29 consists of 99.975% of mixture M28 and 0.025% of compound ST-3a-1 indicated above.

[0689] Mixture M30

[0690]

[0691]

[0692] Mixture M31

[0693]

[0694] Mixture M32

[0695]

[0696] Mixture M33

[0697]

[0698]

[0699] Mixture M34

[0700]

[0701] Mixture M35

[0702]

[0703]

[0704] Mixture M36

[0705]

[0706] Mixture M37

[0707]

[0708] Mixture M38

[0709]

[0710]

[0711] Mixture M39

[0712]

[0713] Mixture M40

[0714]

[0715] Mixture M41

[0716]

[0717] Mixture M42

[0718]

[0719] Mixture M43

[0720]

[0721]

[0722] Mixture M44

[0723]

[0724] Mixture M45

[0725]

[0726] Mixture M46

[0727]

[0728]

[0729] Mixture M47

[0730]

[0731] Mixture M48

[0732]

[0733] Mixture M49

[0734]

[0735] Mixture M50

[0736]

[0737] Mixture M51

[0738]

[0739]

[0740] Mixture M52

[0741]

[0742] Mixture M53

[0743]

[0744] Mixture M54

[0745]

[0746]

[0747] Mixture M55

[0748]

[0749] Mixture M56

[0750]

[0751] Mixture M57

[0752]

[0753]

[0754] Mixture M58

[0755]

[0756] Mixture M59

[0757]

[0758] Mixture M60

[0759]

[0760] Mixture M61

[0761]

[0762] Mixture M62

[0763]

[0764]

[0765] Mixture M63

[0766]

[0767] Mixture M64

[0768]

[0769] Mixture M65

[0770]

[0771] Mixture M66

[0772]

[0773] Mixture M67

[0774]

[0775]

[0776] Mixture M68

[0777]

[0778] Mixture M69

[0779]

[0780] Mixture M70

[0781]

[0782] Mixture M71

[0783]

[0784] Mixture M72

[0785]

[0786] Mixture M73

[0787]

[0788] Mixture M74

[0789]

[0790] Mixture M75

[0791]

[0792]

[0793] Mixture M76

[0794]

[0795] Mixture M77

[0796]

[0797] Mixture M78

[0798]

[0799]

[0800] Mixture M79

[0801]

[0802] Mixture M80

[0803]

[0804] Mixture M81

[0805]

[0806]

[0807] Mixture M82

[0808]

[0809] Mixture M83

[0810]

[0811] Mixture M84

[0812]

Claims

1. A liquid crystal medium, characterized in that It contains one or more compounds of formula IA in R 11 represents an alkyl or alkenyl or alkoxy group having 1 to 7 C atoms, and R 12 represents an alkoxy group having 1 to 7 C atoms; and The medium comprises one or more compounds selected from the group consisting of compounds of formulae IIA, IIB, IIC and IID, in R 2A , R 2B , R 2C and R 2D each independently of one another represents H, alkyl or alkenyl with up to 15 C atoms, which is unsubstituted, monosubstituted by CN or CF3 or at least monosubstituted by halogen, wherein in addition, one or more CH2 groups in these radicals are optionally replaced by -O-, -S-, -C≡C-, -CF2O-, -OCF2-, -OC-O- or -O-CO- are replaced in such a way that the O atoms are not directly connected to each other, L 1 To L 4 each independently represents F or Cl, Z 2 , Z 2B and Z 2D each independently represents a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF- or -CH=CHCH2O-, p represents 0, 1 or 2, q represents 0 or 1, and v represents 1 to 6.

2. The medium according to claim 1, wherein the compound of formula IA is selected from the group consisting of compounds of the following formulae: wherein n and m each independently represent 1, 2, 3, 4, 5 or 6.

3. The medium according to claim 1 or 2, wherein the total concentration of the one or more compounds of the formula IA is in the range from 1% to 25% by weight.

4. A medium according to claim 1 or 2, wherein the medium comprises one or more compounds of formula IC in R 11 and R 12 each independently of one another represents H, alkyl or alkoxy having 1 to 15 C atoms, wherein in addition, one or more CH2 groups in these groups are each independently of one another optionally replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- is replaced in such a way that the O atoms are not directly attached to one another, and wherein in addition, one or more H atoms are optionally replaced by halogen, X 1 indicates S or O, and L 11 and L 12 Each independently of one another represents F, Cl, CF3 or CHF2.

5. The medium according to claim 4, wherein in formula IC X 1 represents S, R 11 and R 12 each independently of one another represents alkyl, alkenyl or alkoxy having up to 15 C atoms, and L 11 and L 12 Both mean F.

6. The medium according to claim 1 or 2, wherein the medium additionally comprises one or more compounds selected from the group consisting of compounds of formulae O-1 to O-18, in R 1 and R 2 Each independently has the 2A Point out the meaning.

7. A medium according to claim 1 or 2, characterized in that The medium additionally comprises one or more compounds selected from the group consisting of compounds of formulae T-1 to T-21, in R represents a straight-chain alkyl or alkoxy group having 1 to 6 C atoms, (O) represents -O- or a single bond, m is 0, 1, 2, 3, 4, 5 or 6, and n is 0, 1, 2, 3 or 4.

8. A medium according to claim 1 or 2, wherein the medium comprises one or more polymerizable compounds of formula P P-Sp-A 1 -(Z 1 -A 2 ) z -R P in P represents a polymerizable group, Sp represents a spacer group or a single bond, A 1 , A 2 represents an aromatic, heteroaromatic, alicyclic or heteroaliphatic group, which optionally contains fused rings and which is unsubstituted or mono- or polysubstituted by L, Z 1 Represents -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -(CH2) n1 -, -CF2CH2-, -CH2CF2-, -(CF2) n1 -, -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C≡C-, -CH=CH-CO-O-, -O-CO-CH=CH-, -CH2-CH2-CO-O-, -O-CO-CH2-CH2-, -CR 0 R 00 - or single key, R 0 , R 00 identically or differently represent H or an alkyl group having 1 to 12 C atoms, R represents H, L or P-Sp-, L denotes F, Cl, -CN, P-Sp- or a straight-chain, branched or cyclic alkyl radical 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 one another, and wherein one or more H atoms are each optionally replaced by P-Sp-, F or Cl, z is 0, 1, 2, or 3, n1 is 1, 2, 3, or 4.

9. The medium according to claim 8, wherein the polymerizable compound of formula P is polymerized.

10. A process for preparing a liquid-crystalline medium according to any one of claims 1 to 7, comprising the following steps: One or more compounds of the formula IA according to claim 1 are mixed with one or more mesogenic or liquid-crystalline compounds and optionally with a polymerizable compound as defined in claim 8 and optionally with one or more additives.

11. LC display comprising a liquid-crystalline medium according to any of claims 1 to 9.

12. An LC display according to claim 11, wherein the display is a PSA display.

13. An LC display according to claim 12, wherein the display is a PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS, PS-posi-VA, PS-TN, polymer-stabilised SA-VA or polymer-stabilised SA-FFS display.

14. An LC display according to claim 11, wherein the display is a VA, IPS, U-IPS, FFS, UB-FFS, SA-FFS or SA-VA display.

15. Use of a liquid-crystalline medium according to any one of claims 1 to 9 in electro-optical displays.

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