Liquid crystal medium

Abstract

A liquid crystal medium is provided. The present invention relates to a liquid crystal (LC) medium comprising a compound of formula I as defined in claim 1 and one or more compounds selected from the group of compounds of formulae IIA, IIB, IIC and IID, and to its use for optical, electro-optical and electronic purposes, in particular in LC displays, in particular IPS, FFS, VA or PS-VA displays. TIFF2023531795000254.tif49166TIFF2023531795000255.tif131166

Description

Technical Field

[0001] The present invention relates to a liquid crystal (LC) medium and its use for optical, electro-optical and electronic purposes, in particular for LC displays, in particular for IPS, FFS, VA or PS-VA displays.

Background Art

[0002] One of the currently used liquid crystal display (LCD) modes is the TN ("twisted nematic") mode. However, TN LCDs have the disadvantage that the contrast strongly depends on the viewing angle.

[0003] In addition, so-called VA ("vertically aligned") displays with a wider viewing angle are known. The LC cell of a VA display has an LC medium layer between two transparent electrodes, where the LC medium usually has negative dielectric anisotropy. In the switched-off state, the molecules of the LC layer are oriented perpendicular to the electrode surface (homeotropic) or have a tilted homeotropic orientation. When a voltage is applied to the two electrodes, the reorientation of the LC molecules occurs parallel to the electrode surface.

[0004] Furthermore, OCB ("optically compensated bend") displays are known to be based on the birefringence effect and comprise an LC layer with a so-called "bend" orientation, usually having positive dielectric anisotropy. When a voltage is applied, the reorientation of the LC molecules occurs perpendicular to the electrode surface. In addition, OCB displays usually have one or more birefringent optical retardation films in order to prevent the undesired transparency of the bend cell to light in the dark state. OCB displays have a wider viewing angle and a shorter response time compared to TN displays.

[0005] There is also a so-called IPS ("in-plane switching") display having an LC layer between two substrates, where two electrodes are arranged only on one of the two substrates and preferably have an intermeshed comb-shaped structure. When a voltage is applied to the electrodes, this generates an electric field having a significant component parallel to the LC layer between the electrodes. As a result, reorientation of the LC molecules in the layer plane occurs.

[0006] Furthermore, a so-called FFS ("fringe-field switching") display has been reported (see, in particular, S.H. Jung et al., Jpn. J. Appl. Phys., Vol. 43, No. 3, 2004, p. 1028 (Non-Patent Document 1)). This display has two electrodes on the same substrate, one of which is structured in a comb shape and the other is unstructured. This results in a strong so-called "fringe field", i.e., a strong electric field near the electrode ends, and an electric field having both a strong vertical component and a strong horizontal component across the cell. The FFS display has a low contrast viewing angle dependency. The FFS display usually contains an LC medium having positive dielectric anisotropy and an alignment layer, usually a polyimide alignment layer, which provides a planar alignment for the molecules of the LC medium.

[0007] The FFS display can be operated as an active matrix display or a passive matrix display. In the case of an active matrix display, individual pixels are usually addressed by an integrated non-linear active element, such as a transistor (e.g., a thin-film transistor ("TFT")), while in the case of a passive matrix display, individual pixels are usually addressed by a multiplexing method known from the prior art.

[0008] There is disclosed a fringe field switching (FFS) display having an electrode design and layer thickness similar to that of an FFS display, but comprising an LC medium layer having negative dielectric anisotropy instead of an LC medium layer having positive dielectric anisotropy (see, for example, S.H. Lee et al., Appl. Phys. Lett., Vol. 73, No. 20, 1998, pp. 2882-2883 (Non-Patent Document 2), and S.H. Lee et al., Liquid Crystals, Vol. 39, No. 9, 2012, pp. 1141-1148 (Non-Patent Document 3)). The LC medium having negative dielectric anisotropy exhibits a more preferable director alignment with a smaller tilt and a higher twist alignment property compared to an LC medium having positive dielectric anisotropy. As a result, these displays have higher transmittance. This display further has an alignment layer, preferably a polyimide alignment layer provided on at least one of the substrates, which is in contact with the LC medium and causes planar alignment of the LC molecules of the LC medium. These displays are also known as "ultra-brightness FFS (UB-FFS)" mode displays. These displays require an LC medium with high reliability.

[0009] As used hereinafter, the term "reliability" means the quality of the performance of a display that has undergone various stress loads (such as light load, temperature, humidity, voltage) over time, which includes display effects known to those skilled in the art of LC displays, such as image sticking (planar and line image sticking), non-uniformity, and dirt. As a standard parameter for classifying reliability, the value of the voltage holding ratio (VHR) is usually used, which is a measured value for maintaining a constant voltage in a test display. Among other factors, a high VHR is a prerequisite for high reliability of the LC medium.

[0010] In more recent types of VA displays, the uniform alignment of LC molecules is limited to a plurality of relatively small domains within the LC cell. There may be disclinations between these domains, which are also known as tilt domains. VA displays having tilt domains have a larger viewing angle independent of contrast and intermediate gradations compared to conventional VA displays. In addition, this type of display is easy to manufacture and no longer requires further processing of the electrode surface, for example by rubbing, to uniformly align the molecules in the switched-on state. Instead, the preferred direction of the tilt angle or pretilt angle is controlled by a special design of the electrodes.

[0011] In a so-called MVA ("multidomain vertical alignment") display, this is usually achieved by electrodes with protrusions, which causes local pretilt. As a result, when a voltage is applied, the LC molecules are oriented parallel to the electrode surface in various directions and in various defined regions of the cell. This achieves a "controlled" switch and prevents the formation of interference disclination lines. Although this arrangement improves the viewing angle of the display, however, it results in a reduction in light transmittance. Further development of MVA uses protrusions only on one electrode side, while the opposite electrode has slits, which improves light transmittance. The electrode with slits generates a non-uniform electric field in the LC cell when a voltage is applied, which means that controlled switching is still achieved. The distance between the slits and the protrusions can be increased to further improve light transmittance, but this results in an increase in response time on the one hand. In a so-called PVA ("patterned VA") display, the protrusions are completely redundant in that both electrodes are structured by slits on the opposite side, which results in an increase in contrast and an improvement in light transmittance, but it is technically difficult, and this makes the display more sensitive to mechanical effects ("tapping", etc.). However, for many applications, such as monitors, especially TV screens, a reduction in response time and an improvement in the contrast and brightness (transmittance) of the display are required.

[0012] Further development is the so-called PS ("polymer sustained") or PSA ("polymer sustained alignment") type of display, for which the term "polymer stabilised" is sometimes also used. In these displays, a small amount (e.g., 0.3 wt%, typically less than 1 wt%) of one or more polymerizable compounds (one or more), preferably polymerizable monomer compounds (one or more), is added to the LC medium. After filling the LC medium into the display, it is polymerized or crosslinked in situ, usually by ultraviolet photopolymerization, optionally with a voltage applied to the electrodes of the display. This polymerization is carried out at a temperature at which the LC medium exhibits a liquid crystal phase, usually at room temperature. It has been proven that it is particularly appropriate to add a polymerizable mesogen or liquid crystal compound, also known as a reactive mesogen or "RM", to the LC mixture.

[0013] Unless otherwise indicated, hereinafter the term "PSA" is used when referring to polymer sustained alignment type displays in general, and the term "PS" is used when referring to specific display modes, such as PS-VA, PS-TN, etc.

[0014] Unless otherwise indicated, hereinafter the term "RM" is used when referring to polymerizable mesogens or liquid crystal compounds.

[0015] On the other hand, 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 RM is preferably carried out while applying a voltage in the case of PS-VA and PS-OCB displays, and in the case of PS-IPS displays, it is carried out while applying a voltage or without applying a voltage, preferably without applying a charge. As demonstrable in a test cell, the PS(A) method results in a pretilt in the cell. In the case of a PS-OCB display, for example, it is possible to stabilize the bend structure, thereby eliminating or reducing the offset voltage. In the case of a PS-VA display, the pretilt has a positive effect on the response time. For a PS-VA display, standard MVA or PVA pixels and electrode layouts can be used. However, in addition, it is also possible to adapt, for example, on only one structured electrode side, without protrusions, which significantly simplifies the manufacturing and, as a result, provides very good contrast and at the same time very good light transmittance.

[0016] Furthermore, the so-called positive-VA display ( "positive VA") has proven to be a particularly suitable mode. Similar to conventional VA displays, in the initial state where no voltage is applied, the initial alignment of the LC molecules in a positive VA display is homeotropic, that is, substantially perpendicular to the substrate. However, in contrast to conventional VA displays, a LC medium with positive dielectric anisotropy is used in positive VA displays. Similar to commonly used IPS displays, the two electrodes in a positive VA display are arranged on only one of the two substrates, preferably showing an interdigitated structure. When a voltage is applied to the interdigitated electrodes, this creates an electric field that is substantially parallel to the LC medium layer, and the LC molecules move to an alignment that is substantially parallel to the substrate. In positive VA displays, it has also been proven advantageous that polymer stabilization by adding RM to the LC medium polymerized within the display can thereby achieve a significant reduction in switching time.

[0017] PS-VA displays are described, for example, in European Patent Application Publication No. 1170626 (Patent Document 1), U.S. Patent No. 6,861,107 (Patent Document 2), U.S. Patent No. 7,169,449 (Patent Document 3), U.S. Patent Application Publication No. 2004 / 0191428 (Patent Document 4), U.S. Patent Application Publication No. 2006 / 0066793 (Patent Document 5), and U.S. Patent Application Publication No. 2006 / 0103804 (Patent Document 6). PS-OCB displays are described, for example, in T.-J. Chen et al., Jpn. J. Appl. Phys. Vol. 45, 2006, pp. 2702-2704 (Non-Patent Document 4) and S.H. Kim, L.-C. Chien, Jpn. J. Appl. Phys. Vol. 43, 2004, pp. 7643-7647 (Non-Patent Document 5). PS-IPS displays are described, for example, in U.S. Patent No. 6,177,972 (Patent Document 7) and Appl. Phys. Lett. 1999, Vol. 75 (No. 21), p. 3264 (Non-Patent Document 6). PS-TN displays are described, for example, in Optics Express 2004, Vol. 12 (No. 7), p. 1221 (Non-Patent Document 7).

[0018] The PSA display typically has an alignment phase, such as polyimide, under the layer formed by the phase-separated and polymerized RM that induces the above-mentioned pretilt angle, and the alignment phase gives an initial alignment of LC molecules before the polymer stabilization process.

[0019] For a long time, a rubbed polyimide layer has been used as the alignment layer. However, in the rubbing process, many problems occur, such as unevenness, contamination, electrostatic problems, and fragments. Therefore, instead of the rubbed polyimide layer, it has been proposed to use a polyimide layer prepared by photoalignment that utilizes the alignment order induced by light on the alignment surface. This can be achieved by photodegradation, photodimerization, or photo-isomerization using polarized light.

[0020] However, there is still a need for a suitably derivatized polyimide layer containing photoreactive groups. Generally, the effort and cost for the production of such polyimide layers, the processing of polyimides, and the improvement by bumps or polymer layers are relatively high.

[0021] In addition, an unfavorable interaction between the polyimide alignment layer and certain compounds of the LC medium has often been observed to lead to a decrease in the electrical resistance of the display. Thus, the number of suitable and available LC compounds is significantly reduced, and display parameters such as viewing angle dependence, contrast, and response time, which are intended to be improved by the use of such LC compounds, are sacrificed. Therefore, it has been desired to omit the polyimide alignment layer.

[0022] This has been achieved, depending on the display mode, by adding a self-aligning agent or additive to the LC medium that induces the desired alignment, such as homeotropic or planar alignment, by an in-situ self-organization mechanism. Thereby, the alignment layer on one or both substrates can be omitted. These display modes are also known as "elf-aligned" or "self-aligning" (SA) modes.

[0023] In an SA display, a small amount, typically 0.1 to 2.5%, of a self-aligning additive is added to the LC medium. Suitable self-aligning additives are, for example, compounds having an organic core group that can interact with the substrate surface, cause the alignment of the additive on the substrate surface, and also induce the desired alignment in the LC molecules, and one or more polar anchor groups linked to the organic core group. Preferred self-aligning additives include, for example, a mesogenic group and a linear or branched alkyl side chain terminated with one or more polar anchor groups selected from, for example, hydroxy, carboxy, amino, or thiol groups. The self-aligning additive may also contain one or more polymerizable groups that can be polymerized under the same conditions as the RM used in the PSA process.

[0024] Previously, SA-VA displays and SA-FFS displays have been disclosed. In particular, suitable self-aligning additives for inducing homeotropic alignment for use in SA-VA mode displays are disclosed, for example, in US Patent Application Publication No. 2013 / 0182202 (Patent Document 8), US Patent Application Publication No. 2014 / 0138581 (Patent Document 9), US Patent Application Publication No. 2015 / 0166890 (Patent Document 10), and US Patent Application Publication No. 2015 / 0252265 (Patent Document 11).

[0025] The SA mode can also be used in combination with the PSA mode. Thus, the LC medium for use in such a combined mode display includes both one or more RMs and one or more self-aligning additives.

[0026] Similar to the above-mentioned conventional LC displays, the PSA display can be operated as an active matrix display or a passive matrix display. In the case of an active matrix display, individual pixels are usually addressed by integrated non-linear active elements such as transistors (e.g., thin-film transistors ("TFTs")), while in the case of a passive matrix display, individual pixels are usually addressed by a multiplexing method as known in the prior art.

[0027] The PSA display may also have an alignment layer on one or both of the substrates forming the display cell. The alignment layer is usually applied on the electrode (if such an electrode exists) to induce an initial alignment of the LC molecules in contact with the LC medium. The alignment layer may, for example, include or consist of polyimide, and may be rubbed or prepared by an optical alignment method.

[0028] Particularly for monitors, especially for TV applications, the response time of LC displays However, the optimization of contrast and brightness (and thus also transmittance) continues to be required. Here, the PSA method can offer significant advantages. In particular, in the case of PS-VA, PS-IPS, PS-FFS, and PS-normal-VA displays, a shortening of the response time that is correlated with the pretilt measurable in test cells can be achieved without a significant adverse effect on other parameters.

Prior Art Documents

Patent Documents

[0029]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Patent Document 9

Patent Document 10

Patent Document 11

Non-Patent Documents

[0030]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Non-Patent Document 5

Non-Patent Document 6

Non-Patent Document 7

Summary of the Invention

Problems to be Solved by the Invention

[0031] The present invention is based on the purpose of providing a novel and suitable material in a LC medium that may contain a reactive mesogen (RM) for use in a display and does not have the above-mentioned disadvantages or has a reduced degree thereof. In particular, in this technical field, a liquid crystal medium with high reliability is still required.

[0032] Furthermore, an object of the present invention is to provide an alternative medium in addition to the existing media known to those skilled in the art in order to expand the range of available materials for more specifically optimizing a particular display.

[0033] High contrast requires a high elastic constant to reduce scattering, but this results in a slow response time, which is particularly problematic when a high-contrast display is desired. The object of the present invention is to provide a liquid crystal medium with a fast response speed.

Means for Solving the Problems

[0034] These objects have been achieved by the materials and methods as described herein according to the present invention. Particularly surprisingly, it has been found that by using a liquid crystal host as described hereinafter, the advantageous effects as described above can be achieved.

Embodiments for Carrying Out the Invention

[0035] The present invention relates to a liquid crystal medium containing one or more compounds of formula I, and the medium further contains one or more compounds selected from the group of compounds of formulae IIA, IIB, IIC and IID.

[0036]

Chemical formula

Chemical formula

Chemical formula

[0037]

Chemical formula

[0038] In the formula, R 2A 、R 2B 、R 2C and R 2D each independently represents H, an alkyl or alkenyl group having up to 15 C atoms, which group is unsubstituted, monosubstituted with CN or CF3, or at least monosubstituted with a halogen, provided that in addition, one or more CH2 groups in these groups are such that O atoms are not directly linked to each other, and are replaced by -O-, -S-,

Chemical formula

[0039] Surprisingly, by using the compound of formula I in a medium in combination with one or more compounds of formulae IIA, IIB, IIC and / or IID, a significantly short response time, the parameter γ1 / K1 can be achieved, resulting in a faster switching of the display comprising the medium, while the contrast of the display is not adversely affected or rather improved.

[0040] The compounds of formula I are described in JP-A-2006-037054 and EP 2691490.

[0041] Preferred compounds of formula I are selected from the following sub-formulae.

[0042]

Chemical formula

[0043]

Chemical formula

[0044]

Chemical formula

[0045]

Chemical formula

[0046]

Chemical formula

[0047]

Chemical formula

[0048] In a preferred embodiment, the medium comprises one or more compounds of formula IA.

Chemical formula

Chemical formula

[0049] Preferred compounds of formula IA are compounds IA-1 to IA-15.

[0050]

Chemical formula

[0051]

Chemical formula

[0052]

Chemical formula

[0053] In the compounds of formulae IIA, IIB and IID, Z 2 may have the same or different meanings. In the compounds of formula IIB, Z 2 and Z 2B may have the same or different meanings. In the compounds of formula IID, Z 2 and Z 2D may have the same or different meanings.

[0054] In the compounds of formulae IIA, IIB, IIC and IID, R 2A R 2B R 2C and R 2D each preferably represents an alkyl having 1 to 6 C atoms, especially CH3, C2H5, n-C3H7, n-C4H9, n-C5H 11 .

[0055] In the compounds of formulae IIA, IIB and IID, L 1 , L 2 , L 3 and L 4 are preferably L 1 =L 2 =F and L 3 =L 4 =F, furthermore L 1 =F and L 2 =Cl, L 1 =Cl and L 2 =F, L 3 =F and L 4 =Cl, L 3 =Cl and L 4 =F. In formulae IIA and IIB, Z 2 and Z 2B are preferably, each independently of the other, a single bond, furthermore a -C2H4- bridge.

[0056] In formula IIB, when Z 2 =-C2H4- or -CH2O-, Z 2B is preferably a single bond, and when Z 2B =-C2H4- or -CH2O-, Z 2 is preferably a single bond.

[0057] In formula IID, Z 2D is preferably a single bond.

[0058] In the compounds of formulae IIA, IIB and IID, (O)C v H 2v+1 is preferably OC v H 2v+1 . In the compounds of formula IIC, (O)C v H 2v+1 is preferably C v H 2v+1 .

[0059] In the compounds of formula IIC, L 3 and L 4 are preferably each F.

[0060] Preferred compounds of formula IIA, IIB, IIC and IID are shown below.

[0061] [ka]

[0062] [ka]

[0063] [ka]

[0064] [ka]

[0065] [ka]

[0066] [ka]

[0067] [ka]

[0068] [ka]

[0069] [ka]

[0070] [ka]

[0071] [Chemistry]

[0072] [Chemistry]

[0073] [Chemistry]

[0074] In the formula, parameter a represents 1 or 2, alkyl and alkyl * each independently represents a linear alkyl group having 1 to 6 carbon atoms, alkenyl represents a linear alkenyl group having 2 to 6 carbon atoms, and (O) represents an oxygen atom or a single bond. Alkenyl preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0075] Particularly preferred mixtures according to the invention comprise one or more compounds of formulae IIA-2, IIA-8, IIA-10, IIA-16, II-18, IIA-40, IIA-41, IIA-42, IIA-43, IIB-2, IIB-10, IIB-16, IIC-1 and IID-4.

[0076] The proportion of compounds of formula IIA and / or IIB in the total mixture is preferably at least 20% by weight.

[0077] Particularly preferred media according to the invention contain at least one compound of formula IIC-1, preferably in an amount of more than 3% by weight, in particular more than 5% by weight, particularly preferably in an amount of 5 to 25% by weight.

[0078] [Chemistry]

[0079] wherein alkyl and alkyl * have the meanings given above.

[0080] In a preferred embodiment, the medium according to the invention comprises one or more compounds of formula III.

[0081]

Chemical formula

[0082] wherein R 11 and R 12 each independently of the other represents H or an alkyl or alkoxy group having from 1 to 15 C atoms, provided that in these groups one or more CH2 groups are arranged such that O atoms are not directly linked to each other,

Chemical formula

[0083] In a preferred embodiment of the present invention, the medium comprises one or more compounds of formula III-1 and / or III-2.

[0084]

Chemical formula

[0085] wherein the groups occurring have the same meaning as given above for formula III, preferably R 11 and R 12 each independently represents an alkyl, alkenyl or alkoxy group having up to 15 carbon atoms, more preferably one or both of them represent an alkoxy group, L 11 and L 12 each represents F.

[0086] In a preferred embodiment, the medium comprises one or more compounds of formula III-1 selected from the group of compounds of formula III-1-1 to III-1-10, preferably of formula III-1-6.

[0087] [Chemistry]

[0088] [Chemistry]

[0089] In the formula, alkyl and alkyl * each independently represents a linear alkyl group having 1 to 6 carbon atoms, alkenyl and alkenyl * each independently represents a linear alkenyl group having 2 to 6 carbon atoms, alkoxy and alkoxy * each independently represents a linear alkoxyl group having 1 to 6 carbon atoms, and L 11 and L 12 each independently represents F or Cl, preferably both F.

[0090] In a preferred embodiment, the medium comprises one or more compounds of formula III-2, preferably of formula III-2-6, selected from the group of compounds of formulae III-2-1 to III-2-10.

[0091] [Chemistry]

[0092] [Chemistry]

[0093] In the formula, alkyl and alkyl * each independently represents a linear alkyl group having 1 to 6 carbon atoms, alkenyl and alkenyl * each independently represents a linear alkenyl group having 2 to 6 carbon atoms, alkoxy and alkoxy *represents a linear alkoxyl group having 1 to 6 C atoms each independently of one another, and L 1 and L 2 each independently represents F or Cl, preferably both F.

[0094] In a preferred embodiment of the present invention, the medium comprises one or more compounds of formula IIIA-1 and / or IIIA-2.

[0095]

Chemical formula

[0096] In the formula, L 11 and L 12 have the same meaning as given in formula III, m and n are the same or different and are 0, 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, very preferably 1, (O) represents O or a single bond, Cy represents an alicyclic group having 3, 4 or 5 ring atoms, which may be substituted with alkyl or alkenyl having up to 3 C atoms or halogen or CN, preferably represents cyclopropyl, cyclobutyl or cyclopentyl.

[0097] The compounds of formula IIIA-1 and / or IIIA-2 are preferably additionally included in the medium, alternatively or in addition to the compounds of formula III.

[0098] Very preferred compounds of formula IIIA-1 and IIIA-2 are as follows.

[0099]

Chemical formula

[0100] In the formula, alkoxy is a linear alkoxy group having 1 to 6 C atoms.

[0101] In a preferred embodiment of the present invention, the medium comprises one or more compounds of formula III-3.

[0102]

Chemical formula

[0103] wherein R 11 and R 12 are the same or different and represent H, an alkyl or alkoxy group having 1 to 15 carbon atoms, provided that one or more CH2 groups in these groups are such that O atoms are not directly linked to each other, and are independently replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-,

Chemical formula

[0104] The compound of formula III-3 is preferably selected from the group of compounds of formulae III-3-1 to III-3-11.

[0105]

Chemical formula

[0106]

Chemical formula

[0107] wherein R 12 represents an alkyl having 1 to 7 carbon atoms, preferably ethyl, n-propyl or n-butyl, or alternatively cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl.

[0108] In a preferred embodiment of the present invention, the medium comprises one or more compounds of formulae III-4 to III-6, preferably of formula III-5.

[0109]

Chem.

[0110] In the formula, the parameters have the meanings given above, and R 11 preferably represents a linear alkyl, and R 12 preferably represents an alkoxy, each having 1 to 7 C atoms.

[0111] In a preferred embodiment, the medium comprises one or more compounds of formula I selected from the group of compounds of formulae III-7 to III-9, preferably one or more compounds of formula III-8.

[0112]

Chem.

[0113] In the formula, the parameters have the meanings given above, and R 11 preferably represents a linear alkyl, and R 12 preferably represents an alkoxy, each having 1 to 7 C atoms.

[0114] In a preferred embodiment, the medium comprises one or more compounds of formula IV.

[0115]

Chem.

[0116] In the formula, R 41 represents an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkenyl group having 2 to 7 C atoms, preferably an n-alkyl group, particularly preferably having 2, 3, 4 or 5 C atoms, R 42is an unsubstituted alkyl group having 1 to 7 carbon atoms or an unsubstituted alkoxy group having 1 to 6 carbon atoms (both preferably having 2 to 5 carbon atoms), an unsubstituted alkenyl group having 2 to 7 carbon atoms, preferably having 2, 3 or 4 carbon atoms, more preferably a vinyl group or a 1-propenyl group, particularly a vinyl group.

[0117] The compound of formula IV is preferably selected from the group of compounds of formulae IV-1 to IV-4.

[0118] [Chemical formula]

[0119] In the formula, alkyl and alkyl’ each independently represent an alkyl having 1 to 7 carbon atoms, preferably having 2 to 5 carbon atoms, alkenyl represents an alkenyl group having 2 to 5 carbon atoms, preferably having 2 to 4 carbon atoms, particularly preferably having 2 carbon atoms, alkenyl’ represents an alkenyl group having 2 to 5 carbon atoms, preferably having 2 to 4 carbon atoms, particularly preferably having 2 to 3 carbon atoms, alkoxy represents an alkoxy having 1 to 5 carbon atoms, preferably having 2 to 4 carbon atoms.

[0120] Preferably, the medium contains one or more compounds selected from the compounds of formulae IV-1-1 to IV-1-4.

[0121] [Chemical formula]

[0122] Very preferably, the medium according to the invention contains one or more compounds of formula IV-2-1 and / or IV-2-2.

[0123] [Chemical formula]

[0124] Very preferably, the medium according to the invention comprises a compound of formula IV-3, in particular selected from the compounds of formulae IV-3-1 to IV-3-5.

[0125]

Chemical formula

[0126] Very preferably, the medium according to the invention comprises a compound of formula IV-4, in particular selected from the compounds of formulae IV-4-1 and IV-4-2.

[0127]

Chemical formula

[0128] The liquid crystal medium preferably additionally comprises one or more compounds of formula IVa.

[0129]

Chemical formula

[0130] In the formula, R 41 and R 42 each independently represent a linear alkyl, alkoxy, alkenyl, alkoxyalkyl or alkoxy group having up to 12 carbon atoms, and

Chemical formula

[0131] Preferred compounds of formula IVa are shown below.

[0132]

Chemical formula

[0133] In the formula, alkyl and alkyl * each independently represents a linear alkyl group having 1 to 6 carbon atoms.

[0134] The medium according to the present invention preferably contains at least one compound of formula IVa-1 and / or formula IVa-2.

[0135] The proportion of the compound of formula IVa in the whole mixture is preferably at least 5% by weight.

[0136] Preferably, the medium contains one or more compounds of formula IVb-1 to IVb-3.

[0137]

Chemical formula

[0138] In the formula, alkyl and alkyl * each independently represents a linear alkyl group having 1 to 6 carbon atoms, and alkenyl and alkenyl * each independently represents a linear alkenyl group having 2 to 6 carbon atoms.

[0139] The proportion of the biphenyls of formula IV-1 to IV-3 in the whole mixture is preferably at least 3% by weight, particularly 5% by weight or more.

[0140] Among the compounds of formula IVb-1 to IVb-3, the compound of formula IVb-2 is particularly preferred.

[0141] Particularly preferred biphenyls.

[0142]

Chemical formula

[0143] In the formula, alkyl * represents an alkyl group having 1 to 6 C atoms, preferably representing n-propyl. The medium according to the invention particularly preferably comprises one or more compounds of formula IVb-1-1 and / or IVb-2-3.

[0144] In a particularly preferred embodiment, the medium comprises one or more compounds of formula V.

[0145]

Chemical formula

[0146] In the formula, R 51 and R 52 each independently have one of the meanings given to R 41 and R 42 and preferably represent alkyl having 1 to 7 C atoms, preferably n-alkyl, particularly preferably n-alkyl having 1 to 5 C atoms, alkoxy having 1 to 7 C atoms, preferably n-alkoxy, particularly preferably n-alkoxy having 2 to 5 C atoms, alkoxyalkyl having 2 to 7 C atoms, preferably having 2 to 4 C atoms, alkenyl or alkenyloxy, preferably alkenyloxy,

Chemical formula

Chemical formula

[0147] The compound of formula V is preferably selected from the compounds of formulas V1 to V17.

[0148]

Chemical formula

[0149]

Chemical formula

[0150] In the formula, R 1 and R 2 have the meanings shown above for R 2A R 1 and R 2 preferably each independently represent a linear alkyl or alkenyl.

[0151] Preferred media contain one or more compounds of formulas V-1, V-3, V-4, V-6, V-7, V-10, V-11, V-12, V-14, V-15 and / or V-16.

[0152] The mixture according to the invention very particularly preferably contains the compounds of formulas V-10, V-12, V-16 and / or IV-1, especially in an amount of 5 to 30%.

[0153] Preferred compounds of formula V-10 are shown below.

[0154]

Chemical formula

[0155] The medium according to the invention particularly preferably contains a tricyclic compound of formula V-10a and / or formula V-10b in combination with one or more bicyclohexyl compounds of formula IV-1. The total proportion of the compounds of formula V-10a and / or V-10b in combination with one or more compounds selected from the bicyclohexyl compounds of formula IV-1 is 5 to 40%, very particularly preferably 15 to 35%.

[0156] A very particularly preferred mixture comprises compound V-10a and CC-2-3.

[0157]

Chem.

[0158] Compound V-10a and IV-1-1 are preferably present in the mixture at a concentration of 15-35%, particularly preferably 15-25%, and especially preferably 18-22% based on the total mixture.

[0159] A very particularly preferred mixture comprises compound V-10b and IV-1-1.

[0160]

Chem.

[0161] Compound V-10b and IV-1-1 are preferably present in the mixture at a concentration of 15-35%, particularly preferably 15-25%, and especially preferably 18-22% based on the total mixture.

[0162] A very particularly preferred mixture comprises the following three compounds.

[0163]

Chem.

[0164] Compound V-10a, V-10b and IV-1-1 are preferably present in the mixture at a concentration of 15-35%, particularly preferably 15-25%, and especially preferably 18-22% based on the total mixture.

[0165] A preferred mixture comprises at least one compound selected from the group consisting of compounds V-6, V-7 and IV-1.

[0166]

Chem.

[0167] In the formula, R 41 and R 42 as well as R 51 and R 52 have the meanings shown above. Preferably, in compounds V-6, V-7 and IV-1, R 41 and R 51 each represent alkyl or alkenyl having 1 to 6 or 2 to 6 C atoms, and R 42 and R 52 represent alkyl having 2 to 6 C atoms.

[0168] Preferred mixtures contain at least one compound of the formulas V-6a, V-6b, V-7a, V-7b, IV-4-1, IV-4-2, IV-3a and IV-3b.

[0169]

Chemical formula

[0170]

Chemical formula

[0171] In the formula, alkyl represents an alkyl group having 1 to 6 C atoms, and alkenyl represents an alkenyl group having 2 to 6 C atoms.

[0172] The compounds of the formulas V-6a, V-6b, V-7a, V-7b, IV-4-1, IV-4-2, IV-3a and IV-3b are preferably present in the mixture according to the invention in an amount of 1 to 40% by weight, preferably 5 to 35% by weight, very particularly preferably 10 to 30% by weight.

[0173] In a preferred embodiment, the medium contains one or more compounds of the formula Va.

[0174]

Chemical formula

[0175] In the formula R L represents H, a linear or branched alkyl or alkoxy group having 1 to 15 C atoms, provided that in these groups, one or more CH2 groups are arranged such that O atoms are not directly linked to each other,

Chemical formula

[0176] The compound of formula Va is preferably selected from the group of compounds of formula Va-1 and Va-2.

[0177]

Chemical formula

[0178] In the formula R L1 has the meaning given for formula I above, and preferably represents alkyl or alkoxy having 1 to 7 C atoms, and a CH2 group in the group may be replaced by cyclopropane-1,2-diyl.

[0179] In a preferred embodiment, the medium comprises one or more compounds of formula Vb selected from the following sub-formulas.

[0180]

Chemical formula

[0181] In the formula, R L1 has the meaning given to Va above.

[0182] Very preferably, the medium comprises a compound Vb-2 in which R L1 represents an alkyl or alkenyl having up to 7 C atoms, in particular vinyl.

[0183] In a preferred embodiment of the invention, the medium additionally comprises one or more compounds of formulas VI-1 to VI-9.

[0184]

Chemical formula

[0185]

Chemical formula

[0186] In the formula, R 7 each independently has one of the meanings shown for R in claim 5 2A and w and x each independently represent 1 to 6.

[0187] A mixture comprising at least one compound of formula V-9 is particularly preferred.

[0188] In a preferred embodiment of the invention, the medium additionally comprises one or more compounds of formulas VII-1 to VII-21.

[0189]

Chemical formula

[0190]

Chemical formula

[0191] [Chemistry]

[0192] In the formula, R represents a linear 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 1, 2, 3 or 4.

[0193] R preferably represents methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy.

[0194] The medium according to the invention preferably contains terphenyls of the formulas VII-1 to VII-21 in an amount of 2 to 30% by weight, in particular 5 to 20% by weight.

[0195] Compounds of the formulas VII-1, VII-2, VII-4, VII-20 and VII-21 are particularly preferred. In these compounds, R preferably represents alkyl and further alkoxy each having 1 to 5 C atoms. In the compound of formula VII-20, R preferably represents alkyl or alkenyl, in particular alkyl. In the compound of formula VII-21, R preferably represents alkyl.

[0196] When the value of Δn of the mixture is 0.1 or more, terphenyls are preferably employed in the mixture according to the invention. Preferred mixtures contain 2 to 20% by weight of one or more terphenyl compounds selected from the group of compounds VII-1 to VII-21.

[0197] Even more preferred embodiments are listed below.

[0198] a) A liquid crystal medium containing at least one compound of the formulas Z-1 to Z-7.

[0199] [Chemistry]

[0200] In the formula, R and alkyl have the meanings shown in formula III above.

[0201] b) Preferred liquid crystal media according to the invention contain one or more substances containing tetrahydronaphthyl or naphthyl units such as compounds of formulas N-1 to N-5.

[0202]

Chemical formula

[0203] In the formula, R 1N and R 2N each independently have the meaning shown for R 2A and preferably represent linear alkyl, linear alkoxy or linear alkenyl. Z 1 and Z 2 each independently represent -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.

[0204] c) Preferred mixtures contain one or more compounds selected from the group of difluorodibenzochroman compounds of formula BC, chromans of formula CR, fluorinated phenanthrenes of formulas PH-1 and PH-2, and fluorinated dibenzofurans of formulas BF-1 and BF-2.

[0205]

Chemical formula

[0206] In the formula, R B1 , R B2 , R CR1 , R CR2 , R 1 , R 2Each independently of the others is R 2A has the meaning of, c is 0, 1 or 2, and d represents 1 or 2. R 1 and R 2 preferably each independently of the others represents an alkyl or alkoxy having 1 to 6 C atoms. The compounds of formulas BF-1 and BF-2 must not be identical to one or more compounds of formula I.

[0207] The mixture according to the invention preferably contains the compounds of formulas BC, CR, PH-1, PH-2 and / or BF in an amount of 3 to 20% by weight, in particular in an amount of 3 to 15% by weight.

[0208] Particularly preferred compounds of formulas BC and CR are compounds BC-1 to BC-7 and CR-1 to CR-5.

[0209]

Chemical formula

[0210]

Chemical formula

[0211] In the formula, alkyl and alkyl * each independently of the others represents a linear alkyl group having 1 to 6 C atoms, alkenyl and alkenyl * each independently of the others represents a linear alkenyl group having 2 to 6 C atoms.

[0212] A mixture containing one, two or three compounds of formula BC-2 is very particularly preferred.

[0213] d) Preferred mixtures contain one or more indane compounds of formula In.

[0214]

Chemical formula

[0215] In the formula, R 11 , R 12 , R 13 each independently represents a linear alkyl, alkoxy, alkoxyalkyl or alkenyl group having 1 to 6 carbon atoms, R 12 and R 13 additionally represent halogen, preferably F, [Chemical formula] represents, i represents 0, 1 or 2.

[0216] Preferred compounds of formula In are the compounds of formulae In-1 to In-16 shown below.

[0217] [Chemical formula]

[0218] [Chemical formula]

[0219] [Chemical formula]

[0220] Compounds of formulae In-1, In-2, In-3 and In-4 are particularly preferred.

[0221] Compounds of formula In and sub-formulae In-1 to In-16 are preferably employed in the mixture according to the invention at a concentration of 5% by weight or more, in particular 5 to 30% by weight, very particularly preferably 5 to 25% by weight.

[0222] e) Preferred mixtures additionally contain one or more compounds of formulae L-1 to L-11.

[0223] [Chemical formula]

[0224] [Chemical formula]

[0225] In the formula, R and R 1 each independently have the meaning shown for R 2A in formula IIA above, and alkyl represents an alkyl group having 1 to 6 carbon atoms. The parameter s represents 1 or 2.

[0226] The compounds of formulas L1 to L5 are preferably used at a concentration of 5 to 50% by weight, particularly 5 to 40% by weight, and very particularly preferably 10 to 40% by weight.

[0227] f) Preferred mixtures additionally contain one or more compounds of formula IIA-Y.

[0228] [Chemical formula]

[0229] In the formula, R 11 and R 12 have one of the meanings given in formula I above, and L 1 and L 2 represent the same or different F or Cl.

[0230] Preferred compounds of formula IIA-Y are selected from the group consisting of the following sub-formulas.

[0231] [Chemical formula]

[0232] [Chemical formula]

[0233] wherein Alkyl and Alkyl * each independently represents a linear alkyl group having 1 to 6 carbon atoms, Alkoxy represents a linear alkoxy group having 1 to 6 carbon atoms, Alkenyl and Alkenyl * each independently represents a linear alkenyl group having 2 to 6 carbon atoms, and O represents an oxygen atom or a single bond. Alkenyl and Alkenyl * preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0234] Particularly preferred compounds of formula IIA-Y are selected from the group consisting of the following sub-formulas.

[0235]

Chemical formula

[0236] wherein Alkoxy and Alkoxy * has the meaning defined above and preferably represents methoxy, ethoxy, n-propyloxy, n-butyloxy or n-pentyloxy.

[0237] The liquid crystal medium according to the invention is also referred to herein as a liquid crystal host mixture and is suitable for use in polymer-stabilized displays. For this purpose, the medium according to the invention may contain one or more polymerizable compounds of formula P.

[0238]

Chemical formula

[0239] wherein the individual groups each independently have the following meaning, the same or different at each occurrence: P is a polymerizable group, Sp is a spacer group or a single bond, A 1 , A 2 is an aromatic, heteroaromatic, alicyclic or heterocyclic group, preferably having 4 to 25 ring atoms, which group may also include a fused ring, and which group is unsubstituted or mono- or polysubstituted by L, Z 1 is -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 a single bond, R 0 , R 00 is H or alkyl having 1 to 12 C atoms, R is H, L or P-Sp-, L is F, Cl, -CN, P-Sp- or linear, branched or cyclic alkyl having 1 to 25 C atoms, provided that one or more non-adjacent CH2 groups may be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- such that O and / or S atoms are not directly linked to each other independently, provided that one or more H atoms may each be replaced by P-Sp-, F or Cl, z is 0, 1, 2 or 3, n1 is 1, 2, 3 or 4.

[0240] As used herein, the terms "active layer" and "switchable layer" refer to a layer in an electro-optical display, such as an LC display, that contains one or more molecules having structural and optical anisotropy, such as LC molecules, whose molecular orientation changes upon an external stimulus such as an electric or magnetic field, resulting in a change in the layer's permeability to polarized or non-polarized light.

[0241] As used herein, the terms "tilt" and "tilt angle" are understood to mean an orientation in which the LC molecules of the LC medium are tilted with respect to the cell surface in an LC display (preferably, a PSA display herein). In this specification, the tilt angle means the average angle (less than 90°) between the molecular long axis (LC director) of the LC molecules and the surface of the flat and parallel outer plates forming the LC cell. In this specification, a low value of the tilt angle (i.e., significantly deviated from the angle of 90°) corresponds to a large tilt. An appropriate method for measuring the tilt angle is given in the examples. Unless otherwise indicated, the values of the tilt angles disclosed above and below relate to this measurement method.

[0242] As used herein, the terms "reactive mesogen" and "RM (reactive mesogen)" are understood to mean a compound containing a mesogen or liquid crystal backbone and one or more functional groups suitable for polymerization linked to the backbone, and the functional groups are also referred to as "polymerizable groups" or "P".

[0243] Unless otherwise stated, as used herein, the term "polymerizable compound" is understood to mean a polymerizable monomer compound.

[0244] As used herein, the term "low molecular weight compound" is a term relative to "polymer compound" or "polymer", and means a monomer and / or a compound not prepared by a polymerization reaction.

[0245] As used herein, the term "non-polymerizable compound" is understood to mean a compound that does not contain functional groups suitable for polymerization under the conditions normally applied for the polymerization of RM.

[0246] As used herein, the term "mesogenic group" is known to those skilled in the art and is described in the literature, and by the anisotropy of its attractive and repulsive interactions, it means a group that essentially contributes to the generation of a liquid-crystalline (LC) phase in low molecular weight or high molecular substances. A compound containing a mesogenic group (mesogenic compound) does not necessarily have an LC phase by itself. Also, it is possible for the mesogenic compound to exhibit LC phase behavior only after mixing with other compounds and / or after polymerization. Typical mesogenic groups are, for example, units having a rigid rod-like or disc-like shape. An overview of the terms and definitions used for mesogens or LC compounds is given in Pure Appl. Chem. 2001, Vol. 73 (No. 5), p. 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, Vol. 116, pp. 6340 - 6368.

[0247] As used herein, the terms "optically active" and "chiral" are synonyms for a material that can induce a helical pitch in a nematic host material, and are also referred to as "chiral dopant".

[0248] As used herein, the term "spacer group", hereinafter also referred to as "Sp", is known to those skilled in the art and is described in the literature, see, for example, Pure Appl. Chem. 2001, Vol. 73 (No. 5), p. 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, Vol. 116, pp. 6340 - 6368. As used herein, the term "spacer group" or "spacer" means a flexible group, such as an alkylene group, that links a mesogenic group and one or more polymerizable groups in a polymerizable mesogenic compound.

[0249] Above and below, [Chem.] represents a trans-1,4-cyclohexylene ring.

[0250] group [Chem.] In, the single bond shown between two ring atoms can be linked to any unbonded position of the benzene ring.

[0251] Above and below, "organic group" represents a carbon or hydrocarbon group.

[0252] "Carbon group" represents a monovalent or polyvalent organic group containing at least one carbon atom, provided that this does not contain any further types of atoms (e.g., -C≡C-), or may contain one or more further atoms such as N, O, S, B, P, Si, Se, As, Te, or Ge (e.g., carbonyl, etc.). The term "hydrocarbon group" additionally contains one or more H atoms and represents a carbon group that may contain one or more heteroatoms such as N, O, S, B, P, Si, Se, As, Te, or Ge.

[0253] "Halogen" represents F, Cl, Br, or I, preferably F or Cl, and very preferably F.

[0254] -CO-, -C(=O)-, and -C(O)- represent a carbonyl group, i.e., [Chem.] represents.

[0255] The carbon or hydrocarbon group may be either a saturated or unsaturated group. The unsaturated group is, for example, an aryl, alkenyl or alkynyl group. The carbon or hydrocarbon group having more than 3 C atoms may be linear, branched and / or cyclic, and may also contain a spiro linkage or a condensed ring.

[0256] Also, terms such as "alkyl", "aryl", "heteroaryl", etc. also include polyvalent groups, for example, alkylene, arylene, heteroarylene, etc.

[0257] The term "aryl" represents an aromatic carbon group or a group derived therefrom. The term "heteroaryl" contains one or more heteroatoms (preferably selected from N, O, S, Se, Te, Si and Ge), and represents "aryl" as defined above.

[0258] Preferred carbon and hydrocarbon groups may be substituted, have 1 to 40, preferably 1 to 20, particularly preferably 1 to 12 C atoms, and are linear, branched or cyclic alkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy, may be substituted, and have 5 to 30, preferably 6 to 25 C atoms, aryl or aryloxy, or may be substituted and have 5 to 30, preferably 6 to 25 C atoms, alkylaryl, arylalkyl, alkylaryloxy, arylalkyloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy, provided that one or more C atoms may preferably be replaced by a heteroatom selected from N, O, S, Se, Te, Si and Ge.

[0259] Even more preferred carbon and hydrocarbon groups are C1-C 20 alkyl, C2-C 20 alkenyl, C2-C 20 alkynyl, C3-C 20 allyl, C4-C 20Alkyldienyl, C4 - C 20 Polyenyl, C6 - C 20 Cycloalkyl, C4 - C 15 Cycloalkenyl, C6 - C 30 Aryl, C6 - C 30 Alkylaryl, C6 - C 30 Arylalkyl, C6 - C 30 Alkylaryloxy, C6 - C 30 Arylalkyloxy, C2 - C 30 Heteroaryl, C2 - C 30 Is heteroaryloxy.

[0260] C1 - C 12 Alkyl, C2 - C 12 Alkenyl, C2 - C 12 Alkynyl, C6 - C 25 Aryl and C2 - C 25 Heteroaryl is particularly preferred.

[0261] More preferred carbon and hydrocarbon groups are linear, branched or cyclic alkyl having 1 - 20, preferably 1 - 12 C atoms, and the group is unsubstituted or mono - or polysubstituted with F, Cl, Br, I or CN, provided that one or more non - adjacent CH2 groups are each independently replaced by -C(R x )=C(R x )-, -C≡C-, -N(R x )-, -O-, -S-, -CO-, -CO - O-, -O - CO-, -O - CO - O- so that O and / or S atoms are not directly linked to each other.

[0262] R xpreferably represents H, F, Cl, CN, an alkyl chain having 1 to 25 C atoms in linear, branched or cyclic form (provided that, additionally, one or more non-adjacent C atoms may be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, provided that one or more H atoms may also be replaced by F or Cl), or an aryl or aryloxy group which may be substituted and has 6 to 30 C atoms, or a heteroaryl or heteroaryloxy group which may be substituted and has 2 to 30 C atoms.

[0263] Preferred alkyl groups are, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl, s-pentyl, cyclopentyl, n-hexyl, cyclohexyl, 2-ethylhexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, dodecanyl, trifluoromethyl, perfluoro-n-butyl, 2,2,2-trifluoroethyl, perfluorooctyl, perfluorohexyl, etc.

[0264] Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, etc.

[0265] Preferred alkynyl groups are, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, octynyl, etc.

[0266] Preferred alkoxy groups are, for example, methoxy, ethoxy, 2-methoxyethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy, 2-methylbutoxy, n-pentoxy, n-hexoxy, n-heptoxy, n-octoxy, n-nonoxy, n-decoxy, n-undecoxy, n-dodecoxy, etc.

[0267] Preferred amino groups are, for example, dimethylamino, methylamino, methylphenylamino, phenylamino and the like.

[0268] Aryl and heteroaryl groups may be monocyclic or polycyclic, i.e., they may contain one ring (e.g., phenyl, etc.) or two or more rings, and the groups may be fused (e.g., naphthyl, etc.) or linked by covalent bonds (e.g., biphenyl, etc.), or may contain a combination of fused and linked rings. Heteroaryl groups preferably contain one or more heteroatoms selected from O, N, S and Se.

[0269] Monocyclic, bicyclic or tricyclic aryl groups having 6 to 25 C atoms and monocyclic, bicyclic or tricyclic heteroaryl groups having 5 to 25 ring atoms are particularly preferred, and these groups may contain fused rings and may be substituted. Further, 5-membered, 6-membered or 7-membered aryl and heteroaryl groups are preferred, provided that in addition, one or more CH groups may be replaced by N, S or O so that O atoms and / or S atoms are not directly linked to each other.

[0270] Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl, [1,1’:3’,1”]terphenyl-2’-yl, naphthyl, anthracene, binaphthyl, phenanthrene, 9,10-dihydrophenanthrene, pyrene, dihydropyrene, chrysene, perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene and the like.

[0271] Preferred heteroaryl groups include, for example, 5-membered rings such as pyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, furan, thiophene, selenophene, oxazole, isoxazole, 1,2-thiazole, 1,3-thiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole; 6-membered rings such as pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine; or fused groups such as indole, isoindole, indolizine, indazole, benzimidazole, benzotriazole, purine, naphthimidazole, phenanthroimidazole, pyridimidazole, pyrazineimidazole, quinoxalineimidazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, benzothiazole, benzofuran, isobenzofuran, dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, benzoisoquinoline, acridine, phenothiazine, phenoxazine, benzopyridazine, benzopyrimidine, quinoxaline, phenazine, naphthyridine, azacarbazole, benzocarbazole, phenanthridine, phenanthroline, thieno[2,3b]thiophene, thieno[3,2b]thiophene, dithienothiophene, isobenzothiophene, dibenzothiophene, benzothiadiazothiophene; or combinations of these groups.

[0272] Also, the aryl and heteroaryl groups described above and below may be substituted with alkyl, alkoxy, thioalkyl, fluorine, fluoroalkyl or a further aryl or heteroaryl group.

[0273] (Non-aromatic) Alicyclic and heterocyclic groups include both saturated rings, i.e., those containing exclusively single bonds, and partially unsaturated rings, i.e., those that may also contain multiple bonds. Heterocyclic rings preferably contain one or more heteroatoms selected from Si, O, N, S, and Se.

[0274] (Non-aromatic) Alicyclic and heterocyclic groups may be monocyclic, i.e., contain only one ring (e.g., cyclohexane, etc.), or polycyclic, i.e., contain multiple rings (e.g., decahydronaphthalene or bicyclooctane, etc.). Saturated groups are particularly preferred. Further, groups that are monocyclic, bicyclic, or tricyclic and have 5 to 25 ring atoms are preferred, and the group may contain fused rings and may be substituted. Further, 5-membered, 6-membered, 7-membered, or 8-membered carbocyclic groups are preferred, provided that in addition, one or more C atoms may be replaced by Si, and / or one or more CH groups may be replaced by N, and / or one or more non-adjacent CH2 groups may be replaced by -O- and / or -S-.

[0275] Preferred alicyclic and heterocyclic groups are, for example, 5-membered groups such as cyclopentane, tetrahydrofuran, tetrahydrothiophene, pyrrolidine, etc., 6-membered groups such as cyclohexane, silinane, cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1,3-dioxane, 1,3-dithiane, piperidine, etc., 7-membered groups such as cycloheptane, etc., and fused groups such as tetrahydronaphthalene, decahydronaphthalene, indane, bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, octahydro-4,7-methanoindane-2,5-diyl, etc.

[0276] Preferred substituents are, for example, dissolution-promoting groups such as alkyl or alkoxy, electron-withdrawing groups such as fluorine, nitro or nitrile, or substituents for increasing the glass transition temperature (Tg) in the polymer, particularly, for example, bulky groups such as t-butyl or optionally substituted aryl groups.

[0277] Preferred substituents are hereinafter also referred to as "L" S ", and include, 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 (provided that one or more H atoms may be replaced by F or Cl), silyl which may be substituted and has 1 to 20 Si atoms, or aryl which may be substituted and has 6 to 25 C atoms, preferably 6 to 15 C atoms.

[0278] In the formula, R x represents H, F, Cl, CN, a linear, branched or cyclic alkyl chain having 1 to 25 C atoms, provided that one or more non-adjacent CH2 groups may be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- so that O- and / S- atoms are not directly linked to each other, provided that one or more H atoms may each be replaced by F, Cl, P- or P-Sp-, and Y 1 represents halogen.

[0279] "Substituted silyl or aryl" is preferably halogen, -CN, R 0 , -OR 0 , -CO-R 0 , -CO-O-R 0 , -O-CO-R 0 or -O-CO-O-R 0means substitution by, provided that R 0 represents H or an alkyl having 1 to 20 C atoms.

[0280] Particularly preferred substituents L are, for example, F, Cl, CN, NO2, CH3, C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5, and further, phenyl.

[0281] A 1 and A 2 are very preferably

Chemical formula

Chemical formula

[0282] The polymerizable group P is a group suitable for polymerization reactions such as free radical or ionic chain polymerization, polyaddition or polycondensation, or for polymer-analogous reactions such as addition or condensation onto the polymer main chain. Groups for chain polymerization, particularly those containing a C=C double bond or a C≡C triple bond, and groups suitable for ring-opening polymerization such as an oxetane or epoxide group are particularly preferred.

[0283] Preferred groups P are CH2=CW 1 -CO-O-, CH2=CW 1 -CO-,

Chemical formula

[0284] A very preferred group P is CH2=CW 1 -CO-O-, CH2=CW 1 -CO- [Chemical] CH2=CW 2 -O-, CH2=CW 2 -, CW 1 =CH-CO-(O) k3 -, CW 1 =CH-CO-NH-, CH2=CW 1 -CO-NH-, (CH2=CH)2CH-OCO-, (CH2=CH-CH2)2CH-OCO-, (CH2=CH)2CH-O-, (CH2=CH-CH2)2N-, (CH2=CH-CH2)2N-CO-, CH2=CW 1 -CO-NH-, CH2=CH-(COO) k1 -Phe-(O) k2 -, CH2=CH-(CO) k1 -Phe-(O) k2 -, Phe-CH=CH- and W 4 W 5 W 6 Selected from the group consisting of Si-, wherein W 1 represents H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular, H, F, Cl or CH3, and W 2 and W 3 each independently of one another represent H or alkyl having 1 to 5 C atoms, in particular, H, methyl, ethyl or n-propyl, and W 4 W 5 and W 6 each independently of one another represent Cl, oxaalkyl or oxocarbonylalkyl having 1 to 5 C atoms, and W 7 and W 8 each independently of one another represent H, Cl or alkyl having 1 to 5 C atoms, Phe represents 1,4-phenylene, k1, k2 and k3 each independently of one another represent 0 or 1, k3 preferably represents 1, and k4 represents an integer from 1 to 10.

[0285] A very particularly preferred group P is CH2=CW 1-CO-O-, especially, CH2=CH-CO-O-, CH2=C(CH3)-CO-O- and CH2=CF-CO-O-, further, CH2=CH-O-, (CH2=CH)2CH-O-CO-, (CH2=CH)2CH-O-,

Chemical formula

[0286] A more preferred polymerizable group P is selected from the group consisting of vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide groups, and most preferably is selected from acrylate and methacrylate.

[0287] When the spacer group Sp is different from a single bond, Sp is preferably of the formula Sp”-X” such that each group P-Sp- corresponds to the formula R-Sp”-X”-, where Sp” and X” have the following meanings.

[0288] Sp” represents a linear or branched alkylene having 1 to 20, preferably 1 to 12 C atoms, which group may be mono- or polysubstituted by F, Cl, Br, I or CN, provided that in addition, one or more non-adjacent CH2 groups are each independently of one another replaced 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- so that O and / or S atoms are not directly linked to each other, X” is -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, R 0 and R 00 each independently represent H or an alkyl having 1 to 20 C atoms, Y 2 and Y 3 each independently represent H, F, Cl or CN.

[0289] X” is preferably -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR 0 -, -NR 0 -CO-, -NR 0 -CO-NR 00 - or a single bond.

[0290] 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 -, where p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R 0 and R 00 have the meanings shown above.

[0291] Particularly preferred spacer groups Sp and -Sp”-X”- are -(CH2) p1 -, -(CH2) p1 -O-, -(CH2) p1 -O-CO-, -(CH2) p1 -CO-O-, -(CH2) p1 -O-CO-O-, provided that p1 and q1 have the meanings given above.

[0292] Particularly preferred groups Sp” are each linear and are ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methylenoxybutylene, ethylenethioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene, ethenylene, propenylene and butenylene.

[0293] In a preferred embodiment of the invention, the compounds of formula P and its sub-formulas contain a spacer group Sp (branched polymerizable group) substituted with one or more polymerizable groups P such that the group Sp-P corresponds to Sp(P) s (where s is 2 or more).

[0294] Preferred compounds of formula P according to this preferred embodiment are those in which s is 2, i.e., 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 formulas.

[0295]

Chemical formula

[0296] In the formula, P is as defined by formula P, alkyl represents a single bond or a straight-chain or branched alkylene having 1 to 12 C atoms, and the group is unsubstituted or mono- or polysubstituted with F, Cl or CN, provided that one or more non-adjacent CH2 groups are each independently of one another such that O and / or S atoms are not directly linked to each other, -C(R 0 )=C(R 0 )-, -C≡C-, -N(R 0 )-, -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O- may be replaced, provided that R 0 has the meaning given above, aa and bb each independently of one another represent 0, 1, 2, 3, 4, 5 or 6, X has one of the meanings shown for X”, and is preferably O, CO, SO2, O-CO-, CO-O or a single bond.

[0297] Preferred spacer group Sp(P)2 is selected from formulae S1, S2 and S3.

[0298] Very preferred spacer group Sp(P)2 is selected from the following sub-formulae.

[0299] [Chemical formula]

[0300] In the compounds of formula P and its sub-formulae as above and below, P is preferably selected from the group consisting of vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide, most preferably acrylate and methacrylate.

[0301] All polymerizable groups P present in the compound have the same meaning, and the compounds of formula P and its sub-formulae as above and below, which very preferably represent acrylate or methacrylate, most preferably methacrylate, are even more preferred.

[0302] In the compounds of formula P and its sub-formulas as described above and below, R preferably represents P-Sp.

[0303] Sp is a single bond or -(CH2) p1 -, -O-(CH2) p1 -, -O-CO-(CH2) p1 or -CO-O-(CH2) p1 where p1 is 2, 3, 4, 5 or 6, and when Sp is -O-(CH2) p1 -, -O-CO-(CH2) p1 or -CO-O-(CH2) p1 the compounds of formula P and its sub-formulas as described above and below in which the O atom or CO group is respectively linked to the benzene ring are more preferred.

[0304] Compounds of formula P and its sub-formulas in which at least one group Sp is a single bond are more preferred.

[0305] At least one group Sp is different from a single bond and is preferably -(CH2) p1 -, -O-(CH2) p1 -, -O-CO-(CH2) p1 or -CO-O-(CH2) p1 where p1 is 2, 3, 4, 5 or 6, and when Sp is -O-(CH2) p1 -, -O-CO-(CH2) p1 or -CO-O-(CH2) p1 the compounds of formula P and its sub-formulas in which the O atom or CO group is respectively linked to the benzene ring are more preferred.

[0306] A very preferred group -A in formula P 1 -(Z-A 2 ) z - is selected from the following formulas.

[0307]

Chemical formula

[0308] In the formula, at least one benzene ring is substituted with at least one group L, and the benzene ring may be further substituted with one or more groups L or P-Sp-.

[0309] Preferred compounds of formula P and their sub-formulas are selected from the following preferred embodiments (including any combination thereof): · All groups P in the compound have the same meaning. · -A 1 -(Z-A 2 ) z - is selected from A1, A2 and A5. · The compound has exactly two polymerizable groups (represented by group P). · The compound has exactly three polymerizable groups (represented by group P). · P is selected from the group consisting of acrylate, methacrylate, and oxetane, and very preferably acrylate or methacrylate. · P is methacrylate. · All groups Sp are single bonds. · At least one of the groups Sp is a single bond, and at least one of the groups Sp is different from a single bond. · When Sp is different from a single bond, -(CH2) p2 -, -(CH2) p2 -O-, -(CH2) p2 -CO-O-, -(CH2) p2 -O-CO-, where p2 is 2, 3, 4, 5 or 6, and the O atom or CO group is each linked to the benzene ring. · Sp is a single bond or -(CH2) p2 -, -(CH2) p2 -O-, -(CH2) p2 -CO-O-, -(CH2) p2 -O-CO- represents, where p2 is 2, 3, 4, 5 or 6, and the O atom or CO group is each linked to the benzene ring. · R represents P-Sp-. ·R does not represent or contain a polymerizable group. ·R does not represent or contain a polymerizable group and represents an alkyl having 1 to 25 C atoms in a linear, branched or cyclic form, provided that one or more non-adjacent CH2 groups are not directly linked to each other by O and / or S atoms and may be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, provided that one or more H atoms may each be replaced by F, Cl or L a and may be replaced by. ·L or L‘ represents F, Cl or CN. ·L is F.

[0310] Suitable and preferred compounds of formula P are selected from the following formulas.

[0311]

Chemical formula

[0312]

Chemical formula

[0313]

Chemical formula

[0314]

Chemical formula

[0315]

Chemical formula

[0316]

Chemical formula

[0317] In the formula, each group has the following meanings: P 1 , P2 and P 3 each independently represents an acrylate or methacrylate group, Sp 1 Sp 2 and Sp 3 each independently represents a single bond or a spacer having one of the meanings shown above and below for Sp, particularly preferably -(CH2) p1 -, -(CH2) p1 -O-, -(CH2) p1 -CO-O-, -(CH2) p1 -O-CO- or -(CH2) p1 -O-CO-O-, where p1 is an integer from 1 to 12, provided in addition that, for at least one of the groups P 1 -Sp 1 -, P 2 -Sp 2 - and P 3 -Sp 3 - being different from R aa one or more groups P 1 -Sp 1 -, P 2 -Sp 2 - and P 3 -Sp 3 - may represent R aa and, R aa is H, F, Cl, CN, or a linear or branched alkyl having 1 to 25 C atoms (provided in addition that one or more non-adjacent CH2 groups are each independently replaced, so that O and / or S atoms are not directly linked to each other, by C(R 0 )=C(R 00 )-, -C≡C-, -N(R 0 )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, and provided in addition that one or more H atoms are F, Cl, CN or P 1 -Sp 1- may be replaced by). Particularly preferably, it represents a linear or branched alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy which may be mono-fluorinated or poly-fluorinated and has 1 to 12 C atoms (however, the alkenyl and alkynyl groups have at least 2 C atoms, and the branched groups have at least 3 C atoms). R 0 and R 00 each independently of one another, in each occurrence, is the same or different and represents H or an alkyl having 1 to 12 C atoms. R y and R z each independently of one another represents H, F, CH3 or CF3. X 1 and X 2 and X 3 each independently of one another represents -CO-O-, -O-CO- or a single bond. Z 1 represents -O-, -CO-, -C(R y R z )- or -CF2CF2-. Z 2 and Z 3 each independently of one another represents -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CF2O-, -OCF2- or -(CH2) n - where n is 2, 3 or 4. L, in each occurrence, is the same or different and represents F, Cl, CN, or a linear or branched alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy which may be mono-fluorinated or poly-fluorinated and has 1 to 12 C atoms, preferably F. L’ and L” each independently of one another represent H, F or Cl. k represents 0 or 1. r represents 0, 1, 2, 3 or 4. s represents 0, 1, 2 or 3, t represents 0, 1 or 2, x represents 0 or 1.

[0318] Compounds of formulas P2, P13, P17, P22, P23, P24, P30, P31 and P32 are particularly preferred.

[0319] Furthermore, the tri-reactive compounds P15 to P30, in particular, P17, P18, P19, P22, P23, P24, P25, P26, P30, P31 and P32 are preferred.

[0320] In the compounds of formulas P1 to P32, the group

Chemical formula

[0321] wherein L is the same or different at each occurrence and has one of the meanings given above and below, 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, particularly F or CH3.

[0322] The medium according to the invention comprises one or more chiral dopants. Preferably, these chiral dopants are in the range of 1 μm -1 ~150 μm -1 preferably in the range of 10 μm -1 ~100 μm -1It has an absolute value of the helical twisting power (HTP) within the range. When the medium contains two or more chiral dopants, these can have opposite signs of their HTP values. This condition is preferred for some specific embodiments as it allows compensating to some extent the chirality of each compound and thus can be used to compensate various temperature-dependent properties of the medium obtained in the device. However, generally, it is preferred that most, preferably all, of the chiral compounds present in the medium according to the invention have the same arithmetic sign of their HTP values.

[0323] Preferably, the chiral dopants present in the medium according to the present application are mesogenic compounds, and most preferably, they exhibit a mesophase alone.

[0324] In a preferred embodiment of the present invention, the medium contains two or more chiral compounds all having the same arithmetic sign of HTP.

[0325] The temperature dependence of the HTP of the individual compounds may be high or low. The temperature dependence of the pitch of the medium can be compensated by mixing compounds having different temperature dependences of HTP in corresponding ratios.

[0326] Regarding the optically active components, for example, a number of chiral dopants such as cholesteryl nonanoate, R- and S-811, R- and S-1011, R- and S-2011, R- and S-3011, R- and S-4011, or CB15 (all from Merck, Darmstadt), some of which are commercially available, are available to those skilled in the art.

[0327] Particularly suitable dopants are compounds containing one or more chiral groups and one or more mesogenic groups, or one or more aromatic or alicyclic groups that form a mesogenic group together with a chiral group.

[0328] Suitable chiral groups are, for example, chiral branched hydrocarbon groups, chiral ethanediol, binaphthol or dioxolane, and furthermore sugar derivatives, sugar alcohols, sugar acids, lactic acid, chiral substituted glycols, steroid derivatives, terpene derivatives, amino acids or monovalent or polyvalent chiral groups selected from the group consisting of sequences of several, preferably 1 to 5 amino acids.

[0329] Preferred chiral groups are sugar derivatives such as glucose, mannose, galactose, fructose, arabinose and dextrose; sugar alcohols such as sorbitol, mannitol, iditol, galactitol or their anhydro derivatives, in particular dianhydrohexitols such as dianhydrosorbitol (1,4:3,6-dianhydro-D-sorbitol, isosorbide), dianhydromannitol (isomannide) or dianhydroiditol (isoidide), etc.; sugar acids such as gluconic acid, gluconic acid and ketogluconic acid, etc.; chiral substituted glycol groups such as mono- or oligoethylene or propylene glycol in which one or more CH2 groups are substituted by alkyl or alkoxy, etc.; amino acids such as alanine, valine, phenylglycine or phenylalanine, or sequences of 1 to 5 of these amino acids; steroid derivatives such as cholesteryl or cholic acid groups, etc.; terpene derivatives such as menthyl, neomenthyl, camphyl, pinyl, terpinyl, isolongiferyl, fenchyl, carenyl, myrtenyl, nopinyl, geranyl, linaloyl, neryl, citronellyl or dihydrocitronellyl.

[0330] The medium according to the invention preferably contains a chiral dopant selected from the group of known chiral dopants. Suitable chiral groups and mesogenic chiral compounds are described, for example, in German Patent No. 3425503, German Patent No. 3534777, German Patent No. 3534778, German Patent No. 3534779 and German Patent No. 3534780, German Patent No. 4342280, European Patent No. 01038941 and German Patent No. 19541820. Examples are also the compounds listed in Table F below.

[0331] The chiral compounds preferably used according to the invention are selected from the group consisting of the formulas shown below.

[0332] Particularly preferred are chiral dopants selected from the group consisting of the compounds of the following formulas A-I to A-III and A-Ch.

[0333] [Chemical formula]

[0334] In the formula, R a11 , R a12 and R b12 each independently represent an alkyl having 1 to 15 carbon atoms, where furthermore, one or more non-adjacent CH2 groups, independently of each other, so that O and / or S atoms are not directly bonded to each other, may be replaced by -C(R z )=C(R z )-, -C≡C-, -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O-, and where furthermore, one or more H atoms may be replaced by F, Cl, Br, I or CN, preferably represents alkyl, more preferably n-alkyl, provided that R a12 is different from R b12 , R a21 and R a22independently of one another, represents alkyl having 1 to 15 carbon atoms, where furthermore, one or more non-adjacent CH2 groups, independently of one another and such that O and / or S atoms are not directly bonded to each other, are replaced by -C(R z )=C(R z )-, -C≡C-, -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O-, where furthermore, one or more H atoms may be replaced by F, Cl, Br, I or CN, preferably both represent alkyl, more preferably n-alkyl, R a31 , R a32 and R b32 independently of one another, represent linear or branched alkyl having 1 to 15 carbon atoms, where furthermore, one or more non-adjacent CH2 groups, independently of one another and such that O and / or S atoms are not directly bonded to each other, are replaced by -C(R z )=C(R z )-, -C≡C-, -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O-, where furthermore, one or more H atoms may be replaced by F, Cl, Br, I or CN, preferably represents alkyl, more preferably n-alkyl, provided that R a32 is different from R b32 , R z represents H, CH3, F, Cl, or CN, preferably H or F, R 8 has one of the meanings of R a11 given above, preferably alkyl having 1 to 15 carbon atoms, more preferably n-alkyl, Z 8 represents -C(O)O-, -CH2O-, -CF2O- or a single bond, preferably -C(O)O-, A 11 is as defined below for A 12 , or

Chemical formula

[0335] A dopant selected from the group consisting of compounds of the following formula is particularly preferred.

[0336] [Chemical formula]

[0337] [Chemical formula]

[0338] In the formula, m is an integer from 1 to 9, the same or different in each occurrence, and n is an integer from 2 to 9, the same or different in each occurrence.

[0339] Particularly preferred compounds of formula A are compounds of formula A-III.

[0340] Even more preferred dopants are derivatives of isosorbide, isomannitol or isoiditol of formula A-IV below.

[0341] [Chemical formula]

[0342] In the formula, the group [Chemical formula] is [Chemical formula] and is preferably dianhydrosorbitol.

[0343] And chiral ethanediols such as diphenylethane diol (hydrobenzoin), particularly mesogenic hydrobenzoin derivatives of formula A-V below, including the unshown (S,S) enantiomer.

[0344] [Chemical formula]

[0345] In the formula, [Chemical formula] Each is independently 1,4-phenylene or 1,4-cyclohexylene, which may be mono-, di- or tri-substituted with L, wherein L is H, F, Cl, CN, or an optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl or alkoxycarbonyloxy having 1 to 7 carbon atoms, c is 0 or 1, X is CH2 or -C(O)-, Z 0 is -COO-, -OCO-, -CH2CH2- or a single bond, R 0 is alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl or alkylcarbonyloxy having 1 to 12 carbon atoms.

[0346] Examples of the compounds of formula IV.

[0347]

Chemical formula

[0348]

Chemical formula

[0349] The compounds of formula A-IV are described in WO 98 / 00428. The compounds of formula A-V are described in GB 2,328,207.

[0350] Particularly highly preferred dopants are the chiral binaphthyl derivatives described in WO 02 / 94805, the chiral binaphthol acetal derivatives described in WO 02 / 34739, the chiral TADDOL derivatives described in WO 02 / 06265, and chiral dopants having at least one fluorinated bridging group and terminal or central chiral groups described in WO 02 / 06196 and WO 02 / 06195.

[0351] The chiral compound of formula A-VI is particularly preferred.

[0352]

Chemical formula

[0353] In the formula, X 1 、X 2 、Y 1 and Y 2 are each independently of the other, F, Cl, Br, I, CN, SCN, SF5, a linear or branched alkyl having 1 to 25 carbon atoms (which may be mono- or polysubstituted with F, Cl, Br, I or CN, and wherein furthermore, one or more non-adjacent CH2 groups are each independently of the other, -O-, -S-, -NH-, NR 0 -, -CO-, -COO-, -OCO-, -OCOO-, -S-CO-, -CO-S-, -CH=CH- or -C≡C- may be replaced), a polymerizable group or a cycloalkyl or aryl having up to 20 carbon atoms (which may be optionally mono- or polysubstituted with a halogen, preferably F, or a polymerizable group), x 1 and x 2 are each independently of the other, 0, 1 or 2, y 1 and y 2 are each independently of the other, 0, 1, 2, 3 or 4, B 1 and B 2 are each independently of the other, an aromatic or partially saturated or fully saturated aliphatic six-membered ring, wherein one or more CH groups may each be replaced with an N atom, and one or more non-adjacent CH2 groups may each be replaced with O and / or S, W 1 and W 2 are each independently of the other, -Z 1 -A 1 -(Z2 -A 2 ) m -R, or one of the two is R 1 or A 3 but both are not H at the same time, or [Chemical formula] is [Chemical formula] and U 1 and U 2 are each independently of the other, CH2, O, S, CO or CS, V 1 and V 2 are each independently of the other, (CH2) n (where 1 to 4 non-adjacent CH2 groups may be replaced by O and / or S), and V 1 and V 2 one of which is [Chemical formula] when [Chemical formula] are both single bonds, n is 1, 2 or 3, Z 1 and Z 2 are each independently of the other, -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR 0 -, -NR 0-CO-, -O-CH2-, -CH2-O-, -S-CH2-, -CH2-S-, -CF2-O-, -O-CF2-, -CF2-S-, -S-CF2-, -CH2-CH2-, -CF2-CH2-, -CH2-CF2-, -CF2-CF2-, -CH=N-, -N=CH-, -N=N-, -CH=CH-, -CF=CH-, -CH=CF-, -CF=CF-, -C≡C-, two combinations of these groups (where two O and / or S and / or N atoms are not directly bonded to each other), (preferably -CH=CH-COO- or -COO-CH=CH-), or a single bond, R x represents alkyl having 1 to 6 carbon atoms, A 1 A 2 and A 3 are each independently of one another 1,4-phenylene in which one or two non-adjacent CH groups may be replaced by N, 1,4-cyclohexylene in which one or two non-adjacent CH2 groups may be replaced by O and / or S, 1,3-dioxolane-4,5-diyl, 1,4-cyclohexenylene, 1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl or 1,2,3,4-tetrahydronaphthalene-2,6-diyl (each of these groups may be mono- or polysubstituted by L), and furthermore A 1 can be a single bond, L is a halogen atom, preferably F, CN, NO2, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl or alkoxycarbonyloxy having 1 to 7 carbon atoms (where one or more H atoms may be replaced by F or Cl), m is each independently 0, 1, 2 or 3, R and R 1are each independently H, F, Cl, Br, I, CN, SCN, SF5, 1 or a linear or branched alkyl having 3 to 25 carbon atoms (which may be mono- or polysubstituted with F, Cl, Br, I or CN, and one or more non-adjacent CH2 groups are -O-, -S-, -NH-, -NR 0 -, -CO-, -COO-, -OCO-, -O-COO-, -S-CO-, -CO-S-, -CH=CH- or -C≡C- and may be replaced), or a polymerizable group.

[0354] The chiral binaphthyl derivative of formula A-VI-1 is particularly preferred.

[0355]

Chemical formula

[0356] In the formula, ring B, R 0 and Z 0 are as defined for formulas A-IV and A-V, and b is 0, 1, or 2.

[0357] In particular, it is selected from the following formulas A-VI-1a to A-VI-1c.

[0358]

Chemical formula

[0359] In the formula, ring B, R 0 and Z 0 are as defined for formula A-VI-1, R 0 is as defined for formula A-IV or is H or an alkyl having 1 to 4 carbon atoms, b is 0, 1 or 2, Z 0 is particularly -OC(O)- or a single bond.

[0360] The concentration of one or more chiral dopants (one or more types) in the LC medium is preferably in the range of 0.001% to 20%, preferably 0.05% to 5%, more preferably 0.1% to 2%, and most preferably 0.5% to 1.5%. These preferred concentration ranges apply in particular to the chiral dopants S-4011 or R-4011 (both from Merck) and chiral dopants having the same or similar HTP. For chiral dopants with a higher or lower absolute value of HTP compared to S-4011, these preferred concentrations must be decreased or increased proportionally respectively according to the ratio of their HTP values to the HTP value of S-4011.

[0361] The pitch p of the LC medium or host mixture according to the invention is preferably in the range of 5 to 50 μm, more preferably 8 to 30 μm, and particularly preferably 10 to 20 μm.

[0362] Preferably, the medium according to the invention contains a stabilizer selected from the group of compounds of formulas ST-1 to ST-19.

[0363] [Chemical formula]

[0364] [Chemical formula]

[0365] [Chemical formula]

[0366] [Chemical formula]

[0367] [Chemical formula] wherein, R STrepresents H, alkyl or alkoxy having 1 to 15 C atoms, where further, one or more non-adjacent CH2 groups in these groups may each be independently replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-,

Chemical formula

Chemical formula

Chemical formula

[0368] Among the compounds of formula ST, the compounds of the following formula are particularly preferred.

[0369]

Chemical formula

[0370]

Chemical formula

[0371]

Chem.

[0372] In the compounds of formulae ST-3a and ST-3b, n preferably represents 3. In the compound of formula ST-2a, n preferably represents 7.

[0373] Particularly highly preferred mixtures according to the invention contain one or more stabilizers from the group of compounds of formulae ST-2a-1, ST-3a-1, ST-3b-1, ST-8-1, ST-9-1 and ST-12.

[0374]

Chem.

[0375]

Chem.

[0376] The compounds of formulae ST-1 to ST-19 are preferably present in the liquid crystal mixtures according to the invention in amounts of from 0.005 to 0.5% by weight, based on the mixture.

[0377] If the mixtures according to the invention contain two or more compounds from the group of compounds of formulae ST-1 to ST-18, and correspondingly in the case of two compounds, the concentration increases to from 0.01 to 1% by weight, based on the mixture.

[0378] However, the total proportion of the compounds of formulae ST-1 to ST-18, based on the mixtures according to the invention, should not exceed 2% by weight.

[0379] The mixtures according to the invention · contain one or more compounds selected from the compounds of formula I, preferably of formulae I-1 to I-14, very preferably of formulae I-1 to I-5, preferably in a total concentration in the range from more than 0% to 20%, more preferably from 2% to 16% or 3% to 15%, particularly preferably from 5% to 14% by weight, based on the mixture.

[0380] The mixture according to the present invention preferably contains

[0381] · at least one compound of formula IIA, preferably in a total concentration in the range of 3% to 25%, more preferably 6% to 20%, particularly preferably 8% to 15%;

[0382] and / or · at least one compound of formula IIA and IIB, preferably in a total concentration in the range of 5% to 30%, more preferably 8% to 25%, particularly preferably 10% to 20%;

[0383] and / or · at least one compound of formula IID, preferably in a total concentration in the range of 5% to 30%, more preferably 8% to 25%, particularly preferably 10% to 20%;

[0384] and / or · at least one compound of formula IIA and IID, preferably in a total concentration in the range of 8% to 35%, more preferably 12% to 30%, particularly preferably 15% to 26%;

[0385] and / or · at least one compound of formula IIA, at least one compound of formula IIB, and at least one compound of formula IID, preferably in a total concentration in the range of 30% to 60%, more preferably 35% to 55%, particularly preferably 40% to 50%;

[0386] and / or · at least one compound of formula IIA, at least one compound of formula IIB, at least one compound of formula IIC, and at least one compound of formula IID, preferably in a total concentration in the range of 30% to 60%, more preferably 35% to 55%, particularly preferably 40% to 50%;

[0387] · One or more compounds of formula III and / or IIIA-1 and / or IIIA-2, preferably one or more compounds of formula III-2 and / or III-3, at a total concentration preferably in the range of 2% to 25%, more preferably 6% to 23%, particularly preferably 8% to 20%;

[0388] and / or · One or more compounds of formula I and formula IV at a total concentration preferably in the range of 35% to 75%, more preferably 40% to 65%, particularly preferably 45% to 55%;

[0389] and / or · One or more compounds of formula I and formula IV and IVb at a total concentration preferably in the range of 35% to 70%, more preferably 40% to 65%, particularly preferably 45% to 60% comprising.

[0390] In particular, the medium is

[0391] · One or more compounds of formula CCOY-n-Om and / or COY-n-Om,

[0392] · One or more compounds CY-n-Om, particularly CY-3-O4, CY-5-O and / or CY-3-O2, at a total concentration preferably in the range of 1% to 20%, preferably 2% to 15%, very preferably 3 to 10% or 3 to 8%;

[0393] and / or · CPY-n-Om, particularly CPY-2-O2, CPY-3-O2 and / or CPY-5-O2, at a concentration preferably more than 0.5%, particularly 7% to 20%;

[0394] and / or · 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, at a concentration preferably more than 3%, particularly 5% to 15%;

[0395] and / or · CLY-n-Om, preferably CLY-2-O4, CLY-3-O2 and / or CLY-3-O3, at a concentration preferably greater than 5%, particularly 15% - 30%, very preferably 20 - 25% based on the total mixture;

[0396] and / or · CLY-n-Om and CY-n-Om at a concentration preferably in the range of 10% - 80% based on the total mixture,

[0397] and / or · CLY-n-Om and PY-n-Om, preferably CLY-3-O2 and / or CLY-3-O3 and / or CLY-4-O2 and PY-3-O2 and / or PY-1-O2, at a concentration preferably 5 - 35%, more preferably 15% - 33% based on the total mixture,

[0398] and / or · CC-V-V at a concentration preferably 5 - 50% based on the total mixture,

[0399] and / or · One or more compounds of formula CC-3-V1 and / or CC-4-V1, preferably at a total concentration in the range of 5 - 40%, more preferably 15% - 35%, particularly preferably 20% - 30%,

[0400] and / or · One or more compounds of formula B-nO-Om and / or B(S)-nO-Om, particularly the compounds B(S)-2O-O4 and / or B(S)-2O-O5, at a concentration preferably in the range of 2 - 10%;

[0401] and / or ·One or more compounds of the formula B-nO-Om and / or B(S)-nO-Om, in particular the compounds B(S)-2O-O4 and / or B(S)-2O-O5 and / or the compounds of the formula COB(S)-n-Om, in particular CO(B)S-2-O4, in a total concentration in the range of 5 to 20%, preferably 7 to 17%;

[0402] and / or ·One or more compounds of the formula B-nO-Om and / or B(S)-nO-Om, in particular the compound B(S)-2O-O5, preferably in a concentration in the range of 2 to 10%, and the compounds CC-3-V1 and / or the compounds CC-4-V1, in a total concentration in the range of 10 to 30%, preferably 15 to 20%,

[0403] and / or ·0.1% to 3% of the compound PPGU-3-F,

[0404] and / or ·More than 0% to 10% of the compound PGIY-nO-Om,

[0405] and / or ·0.1 to 1% of the compound CCQU-n-F,

[0406] and / or ·0 to 5% of the compound of formula Va, in particular Va-2 contained.

[0407] Preferably a medium is additionally added,

[0408] ·One or more compounds of formula IVa-2, in a total concentration in the range of 1 to 20%, preferably 8 to 18%;

[0409] and / or ·One or more compounds of formula IVb-1, in a total concentration in the range of 1 to 10%, preferably 2 to 9%;

[0410] and / or ·One or more compounds of formula V-16 in a total concentration in the range of 1 to 12%, preferably 2 to 10%;

[0411] and / or ·One or more compounds of formula V-10 in a total concentration in the range of 4 to 30%, preferably 5 to 25% are included.

[0412] The present invention further relates to an electro-optical display having an active matrix address, which contains the liquid crystal medium according to claim 1 as a dielectric, and 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-normal-VA, PS-TN, polymer-stabilized SA-VA or polymer-stabilized SA-FFS display.

[0413] The liquid crystal medium according to the present invention preferably has a nematic phase of -20°C or lower to 70°C or higher, particularly preferably -30°C or lower to 80°C or higher, and very particularly preferably -40°C or lower to 90°C or higher, which is advantageous.

[0414] The medium according to the present invention has a clearing temperature of 70°C or higher, preferably 74°C or higher.

[0415] The expression "having a nematic phase" means that on the one hand, no smectic phase and crystallization are observed at a lower temperature corresponding to the temperature, and on the other hand, no clearing occurs when heating from the nematic phase. The examination at low temperature is carried out using a rheometer at the corresponding temperature and confirmed by storing in a test cell having a layer thickness corresponding to electro-optical applications for at least 100 hours. If the storage stability in the test cell at a temperature of -20°C is 1000 hours or more, the medium is called stable at this temperature. In the case of temperatures of -30°C and -40°C, the corresponding times are 500 hours and 250 hours respectively. At high temperature, the clearing point is measured by a conventional method in a capillary.

[0416] The liquid crystal mixture preferably has a nematic phase range of at least 60 K and a flow viscosity ν of at most 30 mm 2 · s -1 at 20 °C. 2 · s -1 at 20 °C. 20 The mixture is nematic at temperatures of -20 °C or lower, preferably -30 °C or lower, very preferably -40 °C or lower.

[0417] The value of the birefringence Δn in the liquid crystal mixture is generally between 0.07 and 0.16, preferably between 0.08 and 0.15, very preferably between 0.09 and 0.14.

[0418] In a preferred embodiment of the invention, the medium has a birefringence in the range from 0.085 to 0.105, preferably from 0.090 to 0.100, in particular from 0.092 to 0.094.

[0419] The liquid crystal mixture according to the invention has a dielectric anisotropy Δε of from -1.5 to -8.0, preferably from -3.0 to -5.0, in particular from -3.5 to -4.5.

[0420] The rotational viscosity γ1 at 20 °C is preferably 160 mPa·s or lower, in particular 130 mPa·s or lower.

[0421] The medium according to the invention has an average elastic constant K of 15 or more, preferably 15.3 or more, very preferably 15.4 or more, in particular 15.5 or 15.6 or more.

[0422] avg The medium according to the invention has a value γ1 / K1 of 7.5 or 7.4 or 7.3 or 7.2 or lower, preferably 6.7 or lower, more preferably 6.5 or lower, in particular 6.3 or lower. has.

[0423] In addition, the liquid crystal medium according to the invention has a high value of the voltage holding ratio in a liquid crystal cell.

[0424]

[0425] ​Generally, a liquid crystal medium having a low address voltage or threshold voltage exhibits a lower voltage holding ratio than one having a high address voltage or threshold voltage, and vice versa.

[0426] In the present invention, the term "dielectrically positive compound" represents a compound having a Δε greater than 1.5, the term "dielectrically neutral compound" represents one having a Δε of -1.5 or more and 1.5 or less, and the term "dielectrically negative compound" represents one having a Δε less than -1.5. The dielectric anisotropy of a compound is determined by measuring the capacitance of a mixture obtained by dissolving 10% of the compound in a liquid crystal host at 1 kHz in at least one test cell having a homeotropic and a homogeneous surface alignment each having a layer thickness of 20 μm. The measurement voltage is typically 0.5 V to 1.0 V, but is always lower than the capacitance threshold of the liquid crystal mixture being considered.

[0427] All values of temperature shown in the present invention are in °C.

[0428] The mixtures according to the present invention are suitable for all VA-TFT applications such as, for example, VAN, MVA, (S)-PVA, ASV, PSA (polymer sustained VA), and PS-VA (polymer stabilized VA). They are further suitable for IPS (in-plane-switching) and FFS (fringe field switching) applications having a negative Δε.

[0429] The nematic liquid crystal mixture in the display according to the present invention generally contains two types of components A and B, which themselves consist of one or more individual compounds.

[0430] Component A has a significantly negative dielectric anisotropy and gives a dielectric anisotropy of -0.5 or less in the nematic phase. In addition to one or more compounds of formula I, component A preferably contains compounds of formulae IIA, IIB, and / or IIC, and further one or more compounds of formula IV-1.

[0431] The proportion of component A is preferably between 45 and 100%, particularly between 60 and 85%.

[0432] For component A, preferably one or more individual compounds having a value of Δε of -0.8 or less are selected. This value must be more negative and must become smaller as the proportion of A in the whole mixture becomes smaller.

[0433] Component B has significant nematogenicity and a kinematic viscosity at 20 °C of 30 mm 2 ·s -1 or less, preferably 25 mm 2 ·s -1 or less and has the following kinematic viscosity.

[0434] Many suitable materials are known to those skilled in the art from the literature. Compounds of formula O-17 are particularly preferred.

[0435] Particularly preferred individual compounds in component B are very low viscosity nematic liquid crystals having a kinematic viscosity at 20 °C of 18 mm 2 ·s -1 or less, preferably 12 mm 2 ·s -1 or less.

[0436] Component B is uniaxially or enantiotropically nematic, has no smectic phase, and can prevent the generation of a smectic phase down to a very low temperature in the liquid crystal mixture. For example, when various highly nematogenic materials are added to a smectic liquid crystal mixture, the nematogenicity of these materials can be compared through the degree of suppression of the smectic phase achieved.

[0437] The mixture may also contain component C which contains a compound having a dielectric anisotropy Δε of 1.5 or more. These so-called positive compounds are generally present in a negative dielectric anisotropy mixture in an amount of 20% by weight or less based on the whole mixture.

[0438] In addition to one or more compounds of formula I, the phase preferably comprises 4 to 15, in particular 5 to 12, particularly preferably less than 10 compounds of formulae IIA, IIB and / or IIC, and optionally one or more compounds of formula IV-1.

[0439] In addition to the compounds of formula IB and of formulae IIA, IIB and / or IIC and optionally IV-1, other components may be present in amounts of, for example, up to 45%, but preferably up to 35%, in particular up to 10%, of the total mixture.

[0440] The other components are preferably selected from azoxybenzenes, benzylideneanilines, biphenyls, terphenyls, phenyl or cyclohexyl benzoates, phenyl or cyclohexyl cyclohexanecarboxylates, phenylcyclohexanes, cyclohexylbiphenyls, cyclohexylcyclohexanes, cyclohexylnaphthalenes, 1,4-biscyclohexylbiphenyls or cyclohexylpyrimidines, phenyl or cyclohexyl dioxanes, optionally halogenated stilbenes, benzyl phenyl ethers, nematic or nematogenic substances from the class of the trans and substituted cinnamic acid esters, in particular known substances.

[0441] The most important compounds suitable as components of this type of liquid-crystalline phase can be characterized by formula IV.

Chemical formula

[0442] In the formula, L and E each represent a carbocyclic or heterocyclic system from the group formed by 1,4-disubstituted benzene and cyclohexane rings, 4,4'-disubstituted biphenyls, phenylcyclohexanes and cyclohexylcyclohexane systems, 2,5-disubstituted pyrimidines and 1,3-dioxane rings, 2,6-disubstituted naphthalenes, di- and tetrahydronaphthalenes, quinazolines and tetrahydroquinazolines. 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-, or represents a C-C single bond, Q represents a halogen, preferably chlorine or -CN, R 20 and R 21 each represent an alkyl, alkenyl, alkoxy, alkoxyalkyl or alkoxycarbonyloxy having up to 18, preferably up to 8 carbon atoms, or one of these groups represents CN, NC, NO2, NCS, CF3, SF5, OCF3, F, Cl or Br.

[0443] In most of these compounds, R 20 and R 21 are different from each other, and one of these groups is usually an alkyl or alkoxy group. Other variants of the proposed substituents are also common. Many such substances or mixtures thereof are commercially available. All of these substances can be prepared by methods known from the literature.

[0444] It goes without saying for those skilled in the art that the VA, IPS or FFS mixtures of the present invention may also include compounds in which H, N, O, Cl and F are substituted with the corresponding isotopes.

[0445] The compound of formula P is optionally added to the mixtures according to the invention, preferably in a concentration of from 0.01 to 5% by weight, particularly preferably from 0.2 to 2% by weight, based on the mixture. These mixtures may optionally also contain initiators, as described, for example, in US Patent No. 6,781,665. Initiators, such as Irganox-1076 from BASF, are preferably added in an amount of from 0 to 1% to the mixture containing the polymerizable compound. This type of mixture can be used in so-called polymer-stabilized VA mode (PS-VA) or PSA (polymer-sustained VA), but the polymerization of the reactive mesogen is intended to be carried out in the liquid crystal mixture after filling the display panel. The 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., generally upon exposure 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 of RM (UV polymerization), and thus, in this specification, such compounds are not considered to be RM.

[0446] The compounds according to the invention can be synthesized by known methods described in the literature (for example, standard works such as Houben-Weyl, Methoden der Organischen Chemie [Methods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart) or by methods analogous thereto, under known reaction conditions suitable for said reactions. Although not mentioned herein, variations known per se can be used herein. In particular, they can be prepared by the methods described in or analogous to the following reaction schemes. Further methods for preparing the compounds of the invention can be obtained from the examples.

[0447] Other mesogenic compounds not explicitly mentioned above can also advantageously be used in the media according to the invention. Such compounds are known to the person skilled in the art.

[0448] The following examples illustrate the present invention without limiting it. However, they show the preferred mixing concept for those skilled in the art, together with the compounds preferably used, their respective concentrations, and their combinations with each other. In addition, the examples illustrate what properties and combinations of properties are available.

[0449] In the present invention and the following examples, the structure of the liquid crystal compound is indicated by an acronym, and the conversion to a chemical formula is carried out according to Tables A to C below. All the groups C n H 2n+1 、C m H 2m+1 and C l H2 l+1 or C n H 2n and C m H 2m are, in each case, a linear alkyl group or an alkylene group having n, m, and l carbon atoms, respectively. Preferably, n, m, and l are each independently 1, 2, 3, 4, 5, 6, or 7 from each other. Table A shows the codes of the ring elements of the nucleus of the compound, Table B lists the cross-linking units, and Table C lists the meanings of the symbols of the left and right end groups of the molecule. The acronym is composed of the code of the ring element having any linking group followed by a first hyphen and the code of the left end group, and a second hyphen and the code of the right end group. Table D shows examples of the structures of the compounds together with their respective abbreviations.

[0450] <Table A: Ring Elements>

[0451]

Table 1

[0452]

Table 2

[0453]

Table 3

[0454] [Table 4]

[0455] <Table B: Crosslinking Unit>

[0456] [Table 5]

[0457] <Table C: End Group>

[0458] [Table 6]

[0459] In the table, n and m are each an integer, and the three dots "..." are places for other abbreviations from this table.

[0460] Apart from the compounds of formula I, IIA, IIB, IIC and / or IID, the mixtures according to the invention preferably contain one or more of the compounds described below.

[0461] The following abbreviations are used: (n, m, k and l are each independently of one another integers, preferably from 1 to 9, preferably from 1 to 7, and k and l may also be 0, preferably from 0 to 4, more preferably 0 or 2, most preferably 2, n is preferably 1, 2, 3, 4 or 5, in the combination "-nO-", preferably 1, 2, 3 or 4, more preferably 2 or 4, m is preferably 1, 2, 3, 4 or 5, in the combination "-Om", preferably 1, 2, 3 or 4, more preferably 2 or 4. The combination "-lVm" is preferably "2V1".)

[0462]

[0463] [Table 7]

[0464]

Table 8

[0465]

Table 9

[0466]

Table 10

[0467]

Table 11

[0468]

Table 12

[0469]

Table 13

[0470]

Table 14

[0471]

Table 15

[0472]

Table 16

[0473]

Table 17

[0474]

Table 18

[0475]

Table 19

[0476]

Table 20

[0477]

Table 21

[0478]

Table 22

[0479]

Table 23

[0480]

Table 24

[0481]

Table 25

[0482]

Table 26

[0483]

Table 27

[0484] Table E shows the chiral dopants that can be added to the LC medium according to the present invention.

[0485]

Table 28

[0486]

Table 29

[0487]

Table 30

[0488]

Table 31

[0489]

Table 32

[0490] Table F shows the exemplary reactive mesogenic compounds that can be used in the LC medium according to the present invention.

[0491]

Table 33

[0492]

Table 34

[0493]

Table 35

[0494]

Table 36

[0495]

Table 37

[0496]

Table 38

[0497]

Table 39

[0498]

Table 40

[0499]

Table 41

[0500]

Table 42

[0501]

Table 43

[0502]

Table 44

[0503]

Table 45

[0504]

Table 46

[0505]

Table 47

[0506]

Table 48

[0507]

Table 49

[0508]

Table 50

[0509]

Table 51

[0510]

Table 52

[0511]

Table 53

[0512]

Table 54

[0513]

Table 55

[0514]

Table 56

[0515]

Table 57

[0516]

Table 58

[0517] In a preferred embodiment, the mixture according to the invention preferably comprises one or more polymerizable compounds selected from the polymerizable compounds of formulae RM-1 to RM-144. Among these, the compounds RM-1, RM-4, RM-8, RM-17, RM-19, RM-35, RM-37, RM-39, RM-40, RM-41, RM-48, RM-52, RM-54, RM-57, RM-64, RM-74, RM-76, RM-88, RM-102, RM-103, RM-109, RM-117, RM-120, RM-121, RM-122 and RM-145 to RM-152 are particularly preferred.

[0518] In another preferred embodiment, the mixture according to the invention comprises one or more polymerizable compounds selected from formulae RM-145 to RM-152, very preferably from formulae RM-147 to RM-152.

[0519] Table G shows self-aligning additives for vertical alignment that can be used in the SA-VA and SA-FFS display LC media according to the invention together with the polymerizable compounds of formula P.

[0520]

Table 59

[0521]

Table 60

[0522]

Table 61

[0523]

Table 62

[0524]

Table 63

[0525]

Table 64

[0526]

Table 65

[0527]

Table 66

[0528]

Table 67

[0529]

Table 68

[0530]

Table 69

[0531]

Table 70

[0532]

Table 71

[0533] In a preferred embodiment, the LC medium, SA-VA and SA-FFS displays according to the invention are combined with one or more RMs of formula P and contain one or more SA additives selected from formulas SA-1 to SA-48, preferably from formulas SA-14 to SA-48, very preferably from formulas SA-20 to SA-34 and SA-44.

Examples

[0534] The following examples are intended to illustrate the invention without limiting it. In the examples, m.p. represents the melting point, C represents the clearing point of the liquid crystal substance in degrees Celsius, and the boiling point is represented by m.p. Further, C represents the crystalline solid state, S represents the smectic phase (the subscript represents the type of phase), N represents the nematic state, Ch represents the cholesteric phase, I represents the isotropic phase, and T g represents the glass transition temperature. The number between two symbols indicates the transition temperature in degrees Celsius.

[0535] The host mixture used for the measurement of the optical anisotropy Δn of a single compound is the commercially available mixture ZLI-4792 (Merck). The dielectric anisotropy Δε is determined using the commercially available mixture ZLI-2857. The physical data of the compound under study are obtained from the change in the dielectric constant of the host mixture after adding the compound under study and the extrapolation to 100% of the compound employed. Generally, 10% of the compound under study is dissolved in the host mixture according to its solubility.

[0536] Unless otherwise indicated, parts or percentage data represent parts by weight or percentages by weight.

[0537] Above and below: V0 represents the capacitance threshold voltage [V] at 20 °C, n e represents the extraordinary refractive index at 20 °C and 589 nm, n0 represents the ordinary refractive index at 20 °C and 589 nm, Δn represents the optical anisotropy at 20 °C and 589 nm, ε ⊥represents the dielectric constant perpendicular to the director at 20 °C and 1 kHz, ε ∥ represents the dielectric constant parallel to the director at 20 °C and 1 kHz, Δε represents the dielectric anisotropy at 20 °C and 1 kHz, cl.p., T(N,I) represents the clearing point [°C], γ1 is the rotational viscosity [mPa·s] at 20 °C, K1 represents the elastic constant [pN] for the "splay" deformation at 20 °C, K2 represents the elastic constant [pN] for the "twist" deformation at 20 °C, K3 represents the elastic constant [pN] for the "bend" deformation at 20 °C, K avg at 20 °C, K avg represents the average elastic constant [pN] defined as K = 1 / 3 × (1.5K1 + K3), and

[0538] Unless otherwise specified, for example, all temperature values shown in this application such as the melting point T(C,N), the transition from the smectic (S) to the nematic (N) phase T(S,N), and the clearing point T(N,I) are shown in degrees Celsius (°C). M.p. represents the melting point. Further, Tg is the glassy state, C is the crystalline state, N is the nematic phase, S is the smectic phase, and I is the isotropic phase. The numbers between these symbols represent the transition temperature.

[0539] For the present invention, unless otherwise specified, the term "threshold voltage" relates to the capacitance threshold (V0), also known as the Frederiks threshold. Also, in the examples, although generally normal, the optical threshold for 10% relative contrast (V 10 ) may also be shown.

[0540] The display used for measuring the capacitance threshold voltage consists of two flat and parallel outer plates made of glass separated by a distance of 20 μm. Each outer plate has an electrode layer on the inner side and an unrubbed polyimide alignment layer on the topmost part, which causes the homeotropic edge alignment of liquid crystal molecules.

[0541] The display or test cell used for measuring the tilt angle consists of two flat and parallel outer plates made of glass separated by a distance of 4 μm. Each outer plate has an electrode layer on the inner side and a polyimide alignment layer on the topmost part. However, the two polyimide layers are rubbed in an antiparallel manner to each other, which causes the homeotropic edge alignment of liquid crystal molecules.

[0542] Unless otherwise explicitly stated, VHR is determined in the equipment model LCM-1 (O0004) commercially available from Toyo Technica Co., Ltd., Japan, after 5 minutes in an oven at 20 °C (VHR 20 ) and 100 °C (VHR 100 ). Unless more precisely stated otherwise, the voltage used has a frequency within the range of 1 Hz to 60 Hz.

[0543] The stability against UV irradiation is examined using the "Sun Test CPS+" manufactured by Heraeus GmbH, Germany, with a xenon lamp NXE1500B. The sealed test cell is irradiated for 2.0 hours without additional heating unless explicitly instructed otherwise. The irradiation power in the wavelength range from 300 nm to 800 nm is 765 W / m 2 V. To simulate the so-called window glass mode, a UV "cut-off" filter with an edge wavelength of 310 nm is used. In each series of experiments, at least 4 test cells are examined for each condition, and the results are shown as the average value of the corresponding individual measured values.

[0544] For example, the decrease in the voltage holding ratio (ΔVHR) usually caused by UV irradiation or exposure to an LCD backlight is determined according to the following formula (1).

[0545]

Number

[0546] To examine the low-temperature stability, also known as 「LTS (low-temperature stability)」, i.e., the stability of the LC mixture in the bulk against the spontaneous crystallization of individual components or the generation of a smectic phase at low temperatures, several sealed bottles, each containing approximately 1 g of material, are stored at one or more predetermined temperatures, typically -10 °C, -20 °C, -30 °C and / or -40 °C, and visually inspected at regular intervals to see if a phase transition is observed. When the first sample shows a change at a predetermined temperature, the time is recorded. The time until the last inspection at which no change is observed is recorded as the LTS for each.

[0547] The ion density for calculating the resistivity is measured using a VHR test cell (cell gap 3.2 μm) with AL16301 polyimide (JSR Corporation, Japan) using an LC material property measurement system model 6254 commercially available from Toyo Technica Co., Ltd., Japan. The measurement is carried out after storing in an oven at 60 °C or 100 °C for 5 minutes.

[0548] The so-called 「HTP」 represents the helical twist force of an optically active substance or a chiral substance in an LC medium (unit: μm). Unless otherwise specified, HTP is measured at a temperature of 20 °C in a commercially available nematic LC host mixture MLD-6260 (Merck).

[0549] The transparent points are measured using a Thermosystem FP900 from Mettler. The optical anisotropy (n) is measured using an Abbe refractometer H005 (with a sodium spectral lamp Na10, 589 nm, at 20 °C). The dielectric anisotropy (Δε) is measured at 20 °C using an LCR meter E4980A from Agilent Technologies (G005) (ε-parallel cell equipped with JALS2096-R1). The threshold voltage (V0) is measured at 20 °C using an LCR meter E4980A from Agilent Technologies (G005) (ε-parallel cell equipped with JALS2096-R1). The rotational viscosity (γ1) is measured at 20 °C using an LCM-2 from Toyo Technik (0002) (gamma1 negative cell equipped with JALS-2096-R1). The elastic constant (K1, splay) is measured at 20 °C using an LCR meter E4980A from Agilent Technologies (G005) (ε-parallel cell equipped with JALS2096-R1). K3: The elastic constant (K3, bend) is measured at 20 °C using an LCR meter E4980A from Agilent Technologies (G005) (ε-parallel cell equipped with JALS2096-R1). The measurement of the elastic constant is known to those skilled in the art and is described on page 147 of the paper by M.J. Bradshaw and E.P. Raynes, Mol. Cryst. Liq. Cryst., 1983, Vol. 91, pp. 145 - 155.

[0550] Unless otherwise specified, all concentrations in the present specification are given as weight percentages with respect to the entire corresponding mixture consisting of 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, Germany, and a temperature of 20 °C applies unless otherwise explicitly stated.

[0551] The following mixture examples having negative dielectric anisotropy are particularly suitable for, for example, IPS and FFS displays, in particular liquid crystal displays having at least one planar alignment layer such as UB-FFS (: ultra-high brightness FFS), as well as VA displays.

[0552] <Mixture Examples and Comparative Examples> Comparative Mix C-1 and Mix Examples N-1 through N-64 have the compositions and properties given in the table below.

[0553] <Comparison mixture C1> [Table 72]

[0554] <Mixture N-1> [Table 73]

[0555] <Mixture N-2> [Table 74]

[0556] [Table 75]

[0557] Comparative Example C-1 is very similar to mixtures N-1 and N-2 in terms of composition, clearing temperature, dielectric anisotropy and birefringence, but does not contain a compound of formula I. Comparing mixture examples N-1 and N-2 with C-1 shows that, unexpectedly, the use of a compound of formula I significantly improves (reduces) the γ1 / K1 value of the liquid crystal media according to the invention, resulting in faster switching of displays containing said media (Table 1). In addition, the K avg In particular, the value of α is unchanged or even improved, corresponding to unchanged or even improved high contrast.

[0558] <Mixture N-3> [Table 76]

[0559] <Mixture N-4>

Table 77

[0560] <Mixture N-5>

Table 78

[0561] <Mixture N-6>

Table 79

[0562] <Mixture N-7>

Table 80

[0563] <Mixture N-8>

Table 81

[0564] <Mixture N-9>

Table 82

[0565] <Mixture N-10>

Table 83

[0566] <Mixture N-11>

Table 84

[0567] The following mixtures N-11 to N-40 contain the stabilizers added as shown above. The amounts of the host mixtures and stabilizers shown in the table are added to give 100% by weight.

[0568] <Table 1: Mixture Containing Stabilizer>

Table 85

[0569]

Table 86

[0570] The chiral nematic mixture N-45 consists of 99.20% of mixture N-11 and 0.80% of chiral dopant S-2011.

[0571]

Chem.

[0572] The mixture N-45 is remarkable for its very high stability under UV load and shows improved switching times.

Claims

1. One or more compounds of formula I, and One or more compounds selected from the group of compounds of formulae IIA, IIB, IIC and IID, and One or more compounds of formula III-3 A liquid crystal medium comprising. 【Chemical 1】 (In the formula, R １ represents H, a linear or branched alkyl or alkoxy group having 1 to 15 C atoms, provided that in these groups, one or more CH ２ groups are each independently such that O atoms are not directly linked to each other 【Chemical 2】 -C≡C-, -CF ２ O-, -OCF ２ -,-CH=CH-,-O-,-CO-O- or -O-CO- and may be replaced, provided that in addition one or more H atoms may be replaced by halogen, 【Chemical Formula 3】 Y １ represents H or CH ３ and n is 0 or 1, v is 1, 2, 3, 4, 5 or 6.) 【Chemical Formula 4】 (In the formula, R ２Ａ , R ２Ｂ , R ２Ｃ and R ２Ｄ each independently represents H, an alkyl or alkenyl group having up to 15 C atoms, which group is unsubstituted, monosubstituted with CN or CF ３ or at least monosubstituted with halogen, provided that in addition in these groups one or more CH ２ groups are such that O atoms are not directly linked to each other, —O—, —S—, 【Chemical Formula 5】 -C≡C-, -CF ２ O-, -OCF ２ - may be replaced by -CO-O- or -O-CO-, L １ ~L ４ each independently represents F, Cl, CF ３ or CHF ２ and Y represents H, F, Cl, CF ３ , CHF ２ or CH ３ and Z ２ 、Z ２Ｂ and Z ２Ｄ each independently represents a single bond, -CH ２ CH ２ -, -CH=CH-, -CF ２ O-, -OCF ２ -, -CH ２ O-, -OCH ２ -, -COO-, -OCO-, -C ２ F ４ -, -CF=CF- or -CH=CHCH ２ O-; p represents 0, 1 or 2, q represents 0 or 1, and v represents an integer from 1 to 6, provided that the compound of formula I is excluded from formula IID.) [Chemical Formula 6] (In the formula, R11, R12 are the same or different and represent H, an alkyl or alkoxy group having 1 to 15 C atoms, provided that one or more CH2 groups in these groups are such that O atoms are not directly linked to each other by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, 【Chemical Formula 7】 -O-, -CO-O- or -O-CO- may be independently replaced with each other, provided that one or more H atoms may be replaced with halogen.)

2. In formula I, [Chemical Formula 8] and, the medium according to claim 1, wherein n is 1.

3. The total concentration of one or more compounds of formula I is 20% by weight or less, and the total concentration of one or more compounds of formula III-3 is 2% to 25% by weight, the medium according to claim 1 or 2.

4. One or more compounds of formula I at a total concentration of 20% by weight or less, and One or more compounds selected from the group of compounds of formulae IIA, IIB, IIC and IID, and One or more compounds of formula III-2 at a total concentration within the range of 2% to 25% by weight, and One or more compounds of formula III-3 at a total concentration within the range of 2% to 25% by weight A liquid crystal medium comprising. 【Chemical Formula 9】 (In the formula, R １ represents H, a linear or branched alkyl or alkoxy group having 1 to 15 C atoms, provided that in these groups, one or more CH ２ groups are each independently such that O atoms are not directly connected to each other 【Chemical 10】 -C≡C-, -CF ２ O-, -OCF ２ - may be replaced by -CH=CH-, -O-, -CO-O- or -O-CO-, provided that one or more H atoms may additionally be replaced by halogen, 【Chemical 11】 Y １ represents H or CH ３ and n is 0 or 1, v is 1, 2, 3, 4, 5 or 6.) 【Chemical 12】 (In the formula, R ２Ａ 、 R ２Ｂ 、 R ２Ｃ and R ２Ｄ each independently represents H, an alkyl or alkenyl group having up to 15 C atoms, which group is unsubstituted, monosubstituted with CN or CF ３ or at least monosubstituted with halogen, provided that in addition one or more CH ２ groups in these groups are such that O atoms are not directly linked to each other, —O—, —S—, 【Chemical Formula 13】 -C≡C-, -CF ２ O-, -OCF ２ - may be replaced by -CO-O- or -O-CO-, L １ ~L ４ each independently represents F, Cl, CF ３ or CHF ２ and Y represents H, F, Cl, CF ３ , CHF ２ or CH ３ and Z ２ 、Z ２Ｂ and Z ２Ｄ are each, independently of one another, a single bond, -CH ２ CH ２ -, -CH=CH-, -CF ２ O-, -OCF ２ -, -CH ２ O-, -OCH ２ -, -COO-, -OCO-, -C ２ F ４ -, -CF=CF- or -CH=CHCH ２ O- represents, p represents 0, 1 or 2, q represents 0 or 1, and v represents an integer from 1 to 6, provided that the compound of formula I is excluded from formula IID.) 【Chemical 14】 (In the formula, R11 and R12 each independently represent an alkyl, alkenyl or alkoxy group having up to 15 C atoms, L11 and L12 each represent F.) 【Chemical Formula 15】 (In the formula, R11 and R12 are the same or different and represent H, an alkyl or alkoxy group having 1 to 15 C atoms, provided that one or more CH2 groups in these groups are such that O atoms are not directly linked to each other and are independently replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, 【Chemical Formula 16】 -O-, -CO-O- or -O-CO-, provided that one or more H atoms may be replaced by halogen. **Claim 5**: One or more compounds of the formula COY-n-OM and one or more compounds of the formula CCOY-n-OM in a total concentration of 20% by weight or less, and one or more compounds selected from the group of compounds of the formulas IIA, IIB, IIC and IID, and one or more compounds of the formula B(S)-nO-OM in a total concentration in the range from 2% to 25% by weight, and one or more compounds of the formula COB(S)-n-OM in a total concentration in the range from 2% to 25% by weight A liquid crystal medium containing them. 【Chemical 17】 (In the formula, n and m are each independently an integer from 1 to 9.) 【Chemical 18】 (In the formula, R ２Ａ , R ２Ｂ , R ２Ｃ and R ２Ｄ each independently represent H, an alkyl or alkenyl group having up to 15 C atoms, which group is unsubstituted, monosubstituted with CN or CF ３ or at least monosubstituted with halogen, provided that in addition one or more CH ２ groups are such that O atoms are not directly linked to each other, —O—, —S—, 【Chemical Formula 19】 -C≡C-, -CF ２ O-, -OCF ２ - may be replaced by -CO-O- or -O-CO-, L １ to L ４ each independently represents F, Cl, CF ３ or CHF ２ and represents Y represents H, F, Cl, CF ３ , CHF ２ or CH ３ and Z ２ 、Z ２Ｂ and Z ２Ｄ are each, independently of one another, a single bond, -CH ２ CH ２ -, -CH=CH-, -CF ２ O-, -OCF ２ -, -CH ２ O-, -OCH ２ -, -COO-, -OCO-, -C ２ F ４ -, -CF=CF- or -CH=CHCH ２ O- and p represents 0, 1 or 2, q represents 0 or 1, and v represents an integer from 1 to 6, provided that the compound of the formula I is excluded from the formula IID.) 【Chemical 20】 (In the formula, n and m are each independently an integer from 1 to 9.) 【Chemical 21】 (In the formula, n and m are each independently an integer from 1 to 9.) **Claim 6** An average elastic constant K greater than 15 pN at 20°C ａｖｇ (provided that K ａｖｇ is defined as follows.) The medium according to any one of claims 1 to 5 having the same. 【Number 1】 (where K １ and K ３ are the splay and bend elastic constants, respectively.) **Claim 7** The medium according to any one of claims 1 to 6, containing one or more compounds of the formula IV. 【Chemical 22】 (In the formula, R ４１ represents alkyl having 1 to 7 carbon atoms or alkenyl having 2 to 7 carbon atoms, and R ４２ represents an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 7 carbon atoms.) **Claim 8** The medium according to any one of claims 1 to 7, containing one or more compounds selected from the group of compounds of the following formula. 【Chemical 23】 **Claim 9** The medium according to any one of claims 1 to 8, containing one or more compounds of the formula V. 【Chemical 24】 (In the formula, R ５１ 、 and R ５２ represent alkyl having 1 to 7 C atoms, alkoxy having 1 to 7 C atoms, or alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7 C atoms, which may be the same or different, 【Chemical 25】 represents Z ５１ 、Z ５２ each independently represents -CH ２ -CH ２ -, -CH ２ -O-, -CH=CH-, -C≡C-, -COO- or a single bond, and n is 1 or 2.) **Claim 10** The medium according to any one of claims 1 to 9, containing a chiral dopant. **Claim 11** The medium according to any one of claims 1 to 10, containing one or more polymerizable compounds of the formula P. 【Chemical 26】 (In the formula, P represents a polymerizable group, Sp represents a spacer group or a single bond, A １ and A ２ are the same or different and preferably represent an aromatic, heteroaromatic, alicyclic or heterocyclic group having 4 to 25 ring atoms, and the group may contain a fused ring, and the group is unsubstituted or mono- or polysubstituted with L, L represents F, Cl, -CN, P-Sp-, or a linear, branched, or cyclic alkyl having 1 to 25 C atoms, provided that one or more non-adjacent CH ２ groups may be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- such that O and / or S atoms are not directly connected to each other, provided that one or more H atoms may each be replaced by P-Sp-, F or Cl, Z １ represents -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -OCH ２ -, -CH ２ O-, -SCH ２ -, -CH ２ S-, -CF ２ O-, -OCF ２ -, -CF ２ S-, -SCF ２ -, -(CH ２ ) ｎ１ -, -CF ２ CH ２ -, -CH ２ CF ２ -, -(CF ２ ) ｎ１ -, -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C≡C-, -CH=CH-CO-O-, -O-CO-CH=CH-, -CH ２ -CH ２ -CO-O-, -O-CO-CH ２ -CH ２ -, -CR ０ R ００ - or represents a single bond, R ０ and R ００ which are the same or different, represent H or alkyl having 1 to 12 C atoms, R represents H, L or P-Sp-, z is 0, 1, 2 or 3, n1 is 1, 2, 3 or 4.) **Claim 12** The medium according to claim 11, wherein the polymerizable compound of the formula P is polymerized. **Claim 13** A method for preparing an LC medium according to any one of claims 1 to 11, A method comprising the step of mixing one or more compounds of formula I with one or more compounds selected from the group consisting of IIA, IIB, IIC and IID of claim 1, and optionally one or more mesogens or liquid crystal compounds and / or the polymerizable compound according to claim 11, and / or one or more additives.

14. An LC display comprising the medium according to any one of claims 1 to 12.

15. The display according to claim 14, which is a PSA display.

16. The display according to claim 15, which is a PS-VA, PS-IPS, PS-FFS, PS-UB-FFS, polymerization-stabilized SA-VA or polymerization-stabilized SA-FFS display.

17. The display according to claim 14, which is a VA, IPS, U-IPS, FFS, UB-FFS, SA-FFS or SA-VA display.

18. Use of the liquid crystal medium according to any one of claims 1 to 12 in an electro-optical display.

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