EP3898890A1

EP3898890A1 - Liquid-crystal medium

Info

Publication number: EP3898890A1
Application number: EP19829495.1A
Authority: EP
Inventors: Harald Hirschmann; Andreas Pohle; Christian Hock; Martina Windhorst; Sabine Schoen
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2018-12-20
Filing date: 2019-12-17
Publication date: 2021-10-27
Also published as: WO2020127193A1; KR20210104826A; US20220112426A1; JP2022514872A; US11920075B2; CN113195682A; DE102019008296A1

Abstract

The present invention relates to a liquid-crystal medium (LC medium), to the use thereof for electro-optical purposes, and to LCDs containing said medium.

Description

Liquid crystalline medium

The present invention relates to a liquid-crystalline medium (LC medium), its use for electro-optical purposes and LC displays containing this medium.

Liquid crystals are mainly used as dielectrics in display devices, since the optical properties of such substances can be influenced by an applied voltage. Electro-optical devices based on liquid crystals are well known to the person skilled in the art and can be based on various effects. Such devices are, for example, cells with dynamic scattering, DAP cells (deformation of aligned phases), guest / host cells, TN cells with a twisted nematic ("twisted nematic") structure, STN cells ("super-twisted nematic") , SBE cells ("superbirefringence effect") and OMI cells ("optical mode interference"). The most common display devices are based on the Schadt-Flelfrich effect and have a twisted nematic structure. The liquid crystal materials must have good chemical and thermal stability and good stability against electric fields and electromagnetic radiation. Furthermore, the liquid crystal materials should have a low viscosity and give short response times, low threshold voltages and a high contrast in the cells.

Furthermore, they should be used at normal operating temperatures, i.e. have a suitable mesophase in the broadest possible range below and above room temperature, for example a nematic or cholesteric mesophase for the above-mentioned cells. Since liquid crystals are generally used as mixtures of several components, it is important that the components are readily miscible with one another. Other properties, such as the electrical conductivity, the

dielectric anisotropy and optical anisotropy must meet different requirements depending on the cell type and application. For example, materials for cells should also be twisted nematic structure have a positive dielectric anisotropy and a low electrical conductivity.

For example, for matrix liquid crystal displays with integrated non-linear elements for switching individual pixels (MLC displays), LC media with large positive dielectric anisotropy, wide nematic phases, relatively low birefringence, very high specific

Resistance, good UV and temperature stability and low vapor pressure are desirable.

Such matrix liquid crystal displays are known. For example, active elements (i.e. transistors) can be used as non-linear elements for the individual switching of the individual pixels. One then speaks of an "active matrix", where one has two types

can distinguish:

1. MOS (Metal Oxide Semiconductor) or other diodes on silicon wafers as substrates. 2. Thin film transistors (TFT) on a glass plate as a substrate.

The use of single-crystal silicon as the substrate material limits the display size, since the modular composition of various partial displays at the joints also leads to problems.

In the more promising type 2, which is preferred, the TN effect is usually used as the electro-optical effect. There are two technologies: TFTs made from compound semiconductors such as CdSe or TFT's based on polycrystalline or amorphous silicon. The latter technology is being worked on with great intensity worldwide.

The TFT matrix is applied to the inside of one glass plate of the display, while the other glass plate carries the transparent counter electrode on the inside. Compared to the size of the pixel electrode, the TFT is very small and practically does not disturb the image. This technology can also be expanded for full color images are, wherein a mosaic of red, green and blue filters is arranged such that each filter element is opposite a switchable picture element.

The TFT displays usually work as TN cells with crossed polarizers in transmission and are illuminated from behind.

The term MFK displays here encompasses any matrix display with integrated non-linear elements, i.e. In addition to the active matrix, displays with passive elements such as varistors or diodes (MIM = metal-insulator-metal).

MLC displays of this type are particularly suitable for TV applications (e.g. pocket TVs) or for high-information displays for computer applications (laptops) and in automobile or aircraft construction. Next

Problems with the angle dependence of the contrast and the

Switching times for MLC displays result in difficulties due to insufficiently high specific resistance of the liquid crystal mixtures [TOGASHI, S., SEKIGUCHI, K., TANABE, H., YAMAMOTO, E., SORIMACHI, K., TAJIMA, E., WATANABE, H., SHIMIZU, H., Proc.

Eurodisplay 84, Sept. 1984: a 210-288 Matrix LCD Controlled by Double Stage Diode Rings, p. 141 ff, Paris; STROMER, M., Proc. Eurodisplay 84, Sept. 1984: Design of the Thin Film Transistors for Matrix Adressing of the Tele vision Liquid Crystal Displays, p. 145 ff, Paris] As the resistance decreases, the contrast of an MLC display deteriorates and the problem of "after image elimination" can occur. Since the specific resistance of the liquid crystal mixture generally decreases over the lifetime of an MLC display due to interaction with the inner surfaces of the display, a high (initial) resistance is very important in order to obtain acceptable service lives. In the case of low-voltage mixtures in particular, it has so far not been possible to achieve very high specific resistances. It is also important that the specific resistance shows the smallest possible increase with increasing temperature and after temperature and / or UV exposure. The low-temperature properties of the mixtures from the prior art are also particularly disadvantageous. It is required that no crystallization and / or smectic phases occur even at low temperatures and that the temperature dependence of the Viscosity is as low as possible. The state-of-the-art MFK displays therefore do not meet today's requirements.

In addition to liquid crystal displays that use backlighting, are also operated transmissively and possibly transflectively, reflective liquid crystal displays are also of particular interest. These reflective liquid crystal displays use the ambient light for information display. This means that they consume significantly less energy than backlit liquid crystal displays with the appropriate size and resolution. Since the TN effect is characterized by a very good contrast, such reflective displays are also in bright

Environmental conditions can still be read well. This is already from simple reflective TN displays, as shown in e.g. B. wristwatches and pocket calculators are known. However, the principle is also based on high-quality, higher-resolution active matrix displays such. B. TFT displays applicable. As in the case of the generally customary transmissive TFT-TN displays, the use of liquid crystals with low birefringence (Dh) is necessary in order to achieve a low optical delay (d · Dh). This slight optical delay leads to a usually acceptable low viewing angle dependence of the contrast (cf. DE 30 22 818). For reflective displays, the use of

Liquid crystals with small birefringence are even more important than with transmissive displays, since reflective displays are the effective ones

Layer thickness that the light traverses is approximately twice as large as in transmissive displays with the same layer thickness.

To realize 3D effects using shutter glasses

especially fast switching mixtures with low

Rotational viscosities and a correspondingly high optical anisotropy (Dh) are used. Electro-optical lens systems with which a 2-dimensional representation of a display in a 3-dimensional

autostereoscopic display can be switched, can be realized using mixtures with high optical anisotropy (Dh). There is therefore still a great need for MLC displays with a very high specific resistance with a large working temperature range, short switching times even at low temperatures and low threshold voltage, which do not show these disadvantages or only to a lesser extent.

With TN (Schadt-Helfrich) cells, LC media are desired, which enable the following advantages in the cells:

extended nematic phase range (especially at low temperatures)

Switchability at extremely low temperatures (out-door use, automotive, avionics) - increased resistance to UV radiation (longer service life), low threshold voltage.

With the FK media available from the prior art, it is not possible to obtain these advantages while maintaining the others

Realizing parameters. Modern LCD flat screens require ever faster switching times for multimedia content, e.g. Films and

To be able to play video games realistically. This in turn requires nematic liquid crystal mixtures which have a very low rotational viscosity gi with a high optical anisotropy An. In order to obtain the required rotational viscosities, substances are sought that have a particularly advantageous gi / clearing point ratio with a high degree of polarity. In the case of higher twisted cells (STN), LC media are desired which enable greater multiplexability and / or lower threshold voltages and / or wider nematic phase ranges (in particular at low temperatures). For this purpose, a further expansion of the available parameter space (clearing point, smectic-nematic transition or melting point, viscosity, dielectric parameters, elastic parameters) is urgently desired. Especially with FK displays for TV and video applications (e.g. LCD TV, monitors, PDAs, notebooks, game consoles) is a clear one

Reduction in switching times desired. This requires LC mixtures with low rotational viscosities and high dielectric anisotropies. At the same time, the LC media should have high clearing points.

The invention has for its object LC media, in particular for the type MFK, TN, PS-TN, STN, ECB, OCB, IPS, PS-IPS, FFS, PS-FFS or to provide positive VA displays which do not or only show the disadvantages mentioned above, and preferably have fast switching times and low rotational viscosities with a high clearing point, and high dielectric anisotropy and a low threshold voltage.

It has now been found that this object can be achieved by using LC media as described below.

The invention relates to a liquid-crystalline (LC) medium, characterized in that it has a positive dielectric anisotropy and contains one or more compounds of the formula IA and one or more compounds of the formula IB

wherein R ¹ and R ^{2 are} each independently alkyl, alkoxy, oxaalkyl or fluoroalkyl, each having 1 to 8 carbon atoms, and wherein the LC medium no compounds selected from

Contains formulas IA and IB in which the radicals R ¹ and R ^{2 have} the meaning given above and in which one or both radicals R ¹ or R ² additionally contain a C = C double bond. The LC medium according to the invention preferably does not contain any

Compounds which contain a C = C double bond, with the exception of a C = C double bond as part of a polymerizable group or an aromatic or unsaturated ring.

Another object of the present invention is the use of LC mixtures according to the invention as described above and below in electro-optical displays, in particular LC displays, preferably in TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, PS-FFS, posi-VA and PS-posi-VA displays, as well as in FK windows and shutter glasses, especially for 3D applications.

Another object of the invention is an electro-optical display, in particular an LC display, preferably of TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, PS-FFS, posi-VA or posi- PS-VA type, an FK window, or shutter glasses for 3D applications, containing an FK medium according to the invention. Surprisingly, it was found that the FK-

Media have a high dielectric anisotropy De, a high birefringence Dh, a low rotational viscosity gi and at the same time high VFIR values and good low-temperature stability. They are therefore particularly good for applications in monitors, notebooks and

Suitable for multimedia devices.

The following meanings apply above and below:

The term "mesogenic group" is known to the person skilled in the art and is described in the literature, and means a group which, through the anisotropy of its attractive and repulsive interactions, contributes significantly to one in low molecular weight or polymeric substances

To cause liquid crystal (LC) phase. Compounds containing mesogenic groups (mesogenic compounds) do not necessarily have to have an LC phase themselves. It is also possible that mesogenic compounds only exhibit LC phase behavior after mixing with others Show compounds and / or after polymerization. Typical mesogenic groups are, for example, rigid rod-shaped or disc-shaped units. An overview of the terms and definitions used in connection with mesogenic or LC compounds can be found in Pure Appl. Chem. 2001, 73 (5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368.

The term "spacer" or "spacer group", also referred to above and below as "Sp", is known to the person skilled in the art and is described in the literature, see for example Pure Appl. Chem. 2001, 73 (5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368. Unless otherwise stated, the term means

"Spacer group" or "spacer" above and below a flexible group, the mesogenic in a polymerizable mesogenic compound

Group and the polymerizable group (s) connects together.

The term "reactive mesogen" or "RM" denotes a compound containing a mesogenic group and one or more functional groups which are suitable for the polymerization (also referred to as polymerizable group or group P).

The terms "low molecular weight compound" and "unpolymerizable."

Compound "denotes, usually monomeric, compounds which have no functional group which is suitable for the polymerization under the usual conditions known to the person skilled in the art, in particular under the conditions used for the polymerization of the RMs.

Unless otherwise stated, the term "polymerizable compound" denotes a monomeric polymerizable compound.

a trans-1,4-cyclohexylene ring, and means a 1,4-phenylene ring. In the formulas above and below, an alkyl radical or

Alkoxy radical can be straight-chain or branched. It is preferably straight-chain, has 2, 3, 4, 5, 6 or 7 carbon atoms and accordingly preferably means ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy or heptoxy, furthermore methyl , Octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octoxy, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy or tetradedoxy.

Oxaalkyl preferably means straight-chain 2-oxapropyl (= methoxymethyl), 2 - (= ethoxymethyl) or 3-oxabutyl (= 2-methoxyethyl), 2-, 3- or

4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6-, or 7 -Oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-,

5-, 6-, 7-, 8- or 9-oxadecyl.

If an alkyl radical is substituted at least once by flalogen, this radical is preferably straight-chain and flalogen is preferably F or CI. In the case of multiple substitution, flalogen is preferably F. The resulting residues also include perfluorinated residues. In the case of single substitution, the fluorine or chlorine substituent can be in any position, but preferably in the co-position.

In the formulas above and below, X ° is preferably F, CI or mono- or polypropylene alkyl or alkoxy radical having 1, 2 or 3 carbon atoms or mono- or polypropylene alkenyl radical having 2 or 3 carbon atoms. X ° is particularly preferably F, CI, CF3, CFIF ₂ , OCF3,

OCF2CHF2, F3, OCFHCF2CHF2, or CH = CF ₂ , very particularly preferably F or OCF3, furthermore CF3, OCF = CF ₂ , OCHF ₂ and OCH = CF ₂ .

The expression "alkyl" or "alkyl *" in this application includes

preferably straight-chain and branched alkyl groups with 1 to 6

Carbon atoms, especially the straight-chain groups methyl, ethyl, propyl, butyl, pentyl and hexyl. Groups of 2 to 5 carbon atoms are generally preferred. The term "fluoroalkyl" preferably encompasses straight-chain groups with terminal fluorine, ie fluoromethyl, 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl, 5-fluoropentyl, 6-fluorohexyl and 7-fluoroheptyl. However, other positions of the fluorine are not excluded.

The term "oxaalkyl" or "alkoxy" preferably includes straight-chain radicals of the formula C _n Fl _{2n + i} -0- (CFl ₂ ) _m , where n and m each independently represent an integer from 1 to 6 m can also be 0 mean. Preferably n = 1 and m is 1 to 6 or m = 0 and n = 1 to 3.

The compounds of the formula IA are preferably selected from the following sub-formulas:

in which the individual radicals, independently of one another and each time the same or different, have the following meanings alkyl, alkyl ^* straight-chain alkyl having 1 -6 carbon atoms, in particular ethyl,

Propyl, butyl or pentyl, alkoxy straight-chain alkoxy with 1 -6 C atoms, especially methoxy

Ethoxy or propoxy.

Particularly preferred compounds of the formula IA and their sub-formulas are selected from the group consisting of the following formulas

IA1 a

In a preferred embodiment, the LC medium according to the invention contains one or more compounds of the formula IA, preferably selected from the group consisting of the formulas IA1 and IA2, particularly preferably selected from the group consisting of the formulas IA1 a, IA1 b and IA2a particularly preferably of the formula IA1 a and / or IA1 b. The individual concentration of each of these compounds is preferably 3 to 25% by weight, particularly preferably 5 to 20% by weight. The total concentration of these compounds is

preferably 10 to 50% by weight, particularly preferably 15 to 40% by weight.

The compounds of the formula IB are preferably selected from the following sub-formula:

alkoxy IB1

wherein "alkyl" and "alkoxy" have the meanings given in formula IA2.

Particularly preferred compounds of the formulas IB and IB1 are selected from the group consisting of the following formulas In a preferred embodiment, the LC medium according to the invention contains one or more compounds of the formula IB, preferably selected from formula IB1, particularly preferably selected from the group consisting of the formulas IB1 a and IB1 b, very particularly preferably of the formula IB1 a. The individual concentration of each of these compounds is preferably 3 to 25% by weight, particularly preferably 8 to 20% by weight. The total concentration of these compounds is preferably 5 to 30% by weight, particularly preferably 8 to 25% by weight.

In a preferred embodiment, the LC medium according to the invention contains one or more compounds of the formula IA, preferably of the formula IA1, very particularly preferably of the formula IA1 a and / or of the formula IA1 b, and one or more compounds of the formula IB, preferably of the formula IB1, very particularly preferably of the formula IB1 a.

In a further preferred embodiment, the

LC medium according to the invention one or more stabilizers.

Preferred stabilizers are selected from the group consisting of the following formulas

wherein the individual radicals, independently of one another and each time the same or different, have the following meaning

R ^a_d straight-chain or branched alkyl having 1 to 10 C atoms,

preferably with 1 to 6 C atoms, particularly preferably with 1 to 4 C atoms, very particularly preferably methyl,

X ^s H, CH ₃ , OH or 0 ',

A ^s straight-chain, branched or cyclic alkylene with 1 to 20 C atoms which is optionally substituted, n is an integer from 1 to 6, preferably 3. Particularly preferred stabilizers of the formula S3 are selected from formula S3A

wherein n2 is an integer from 1 to 12, and wherein one or more F1 atoms in the group (CF are optionally replaced by methyl, ethyl, propyl, butyl, pentyl or flexyl.

Very particularly preferred stabilizers are selected from the group consisting of the following formulas

In a particularly preferred embodiment, this contains

LC medium according to the invention one or more stabilizers selected from the group consisting of formula S1-1, S2-1, S3-1, S3-1, S3-3 and S4-1.

In a further preferred embodiment, the

LC medium according to the invention one or more stabilizers selected from Table D below.

The concentration of the stabilizers, in particular those of the formulas S1-S3 and their sub-formulas, and those of Table D, in which

LC medium according to the invention is preferably 10 to 500 ppm, particularly preferably 20 to 100 ppm.

Further preferred embodiments for the LC media according to the invention are given below:

The LC medium additionally contains one or more compounds selected from the following formulas:

R ° unsubstituted or halogenated alkyl or alkoxy having 1 to 15 carbon atoms, one or more CFh groups in these radicals also being each independently of one another by —CF2O—, - <c> - _, -0-, -CO-O- or -O-CO- can be replaced so that O atoms are not directly linked to each other,

X ° F, CI, halogenated alkyl, halogenated alkoxy or

halogenated alkenyloxy with up to 6 C atoms each.

Y ¹ - ⁶ H or F, Y ° H or CH _3.

Preferred compounds of the formula II and III are those in which Y denotes H.

Further preferred compounds of the formulas II and III are those in which R ° denotes alkyl having 1 to 6 C atoms, preferably ethyl or propyl, and X ° F or OCF ₃ , preferably F.

F

R ° - (HWH VcF ₂₀ - (O x ° 111

F

wherein R ° and X ° have the meaning given in formula II or one of the preferred meanings given above and below.

Preferred compounds are those of the formulas 111, II2 and II3, particularly preferably those of the formulas 111 and II2.

In the compounds of the formulas 111 to II7, R ° preferably denotes alkyl having 1 to 6 C atoms, particularly preferably ethyl or propyl, and X ° preferably denotes F or OCF3, particularly preferably F.

The LC medium contains one or more compounds of the formula II or their sub-formulas in which Y ° is CFI ₃ . The LC medium preferably contains one or more compounds of the formula II selected from the following sub-formulas:

 wherein R ° and X ° have the meaning given in formula II or one of the preferred meanings given above and below.

Preferred compounds are those of the formulas IIA1, IIA2 and IIA3, those of the formulas IIA1 and IIA2 are particularly preferred.

In the compounds of the formulas IIA1 to IIA7, R ° preferably denotes alkyl having 1 to 6 C atoms, particularly preferably ethyl or propyl, and X ° preferably denotes F or OCF3, particularly preferably F.

The LC medium contains one or more compounds of the formula III selected from the following sub-formulas:

Preferred compounds are those of the formula 1111, III4, III6, 11116, 11119 and III20.

In the compounds of the formulas 1111 to 11121, R means

preferably alkyl with 1 to 6 carbon atoms, particularly preferably ethyl or propyl, X ° preferably denotes F or OCF ₃ , particularly preferably F, and Y ² preferably denotes F.

The LC medium contains one or more compounds of the formula III or their sub-formulas as described above and below in which Y ° is CFI ₃ . The LC medium preferably contains one or more compounds of the formula III selected from the following sub-formulas:

wherein R ° and X ° have the meaning given in formula III or one of the meanings given above and below.

Preferred compounds are those of the formula IIIA1, IIIA4, IIIA6, IIIA16, IIIA19 and IIIA20.

In the compounds of the formulas IIIA1 to IIIA21, R ° preferably denotes alkyl having 1 to 6 C atoms, particularly preferably ethyl or propyl, X ° preferably denotes F or OCF3, particularly preferably F, and Y ² preferably denotes F.

wherein R °, X ° and Y ^{1-4 have} the meanings given above, and

Z ° -C2H4-, - (CH ₂ ) 4-, -CH = CH-, -CF = CF-, -C2F4-, -CH2CF2-, -CF2CH2-, -CH ₂ O-, -OCH ₂ -, - COO- or -OCF ₂ -, in formulas V and VI also a single bond, in formulas V and VIII also -CF ₂ O-, r 0 or 1, and s 0 or 1;

The compounds of the formula IV are preferably selected from the following formulas: F

R ° ^“ (IVa

H W H O x °

F

wherein R ° and X ° have the meanings given above.

R ° preferably denotes alkyl having 1 to 6 carbon atoms. X ° preferably denotes F or OCF3, furthermore OCF = CF ₂ or CI;

The compounds of the formula IVa are preferably selected from the following sub-formula:

wherein R ° has the meaning given above and preferably means propyl or pentyl.

The compounds of the formula IVc are preferably selected from the following sub-formulas: wherein R ° has the meaning given above and preferably means propyl or pentyl.

The compound (s) of the formula IVc, in particular of the formula IVc1, is (are) preferably present in the LC medium according to the invention in a concentration of 1-20% by weight, particularly preferably 2-15% by weight.

The compounds of the formula V are preferably selected from the following sub-formulas:

wherein R ° and X ° have the meanings given above.

R ° preferably denotes alkyl having 1 to 6 carbon atoms. X ° preferably denotes F and OCF3, furthermore OCFIF ₂ , CF3, OCF = CF ₂ and OCH = CF ₂ .

The LC medium according to the invention particularly preferably contains one or more compounds of the formula Va1,

in which "alkyl" has the meaning given in formula IA1 and preferably denotes ethyl, propyl or pentyl, very particularly preferably propyl.

The compounds of the formula VI are preferably selected from the following sub-formulas: wherein R ° and X ° have the meanings given above.

R ° preferably denotes alkyl having 1 to 6 carbon atoms. X ° preferably denotes F, furthermore OCF3, CF3, CF = CF2, OCFIF2 and OCFI = CF2.

The LC medium according to the invention particularly preferably contains one or more compounds of the formula VIb1 and / or Much, in which "alkyl" has the meaning given in formula IA1 and preferably denotes ethyl, propyl or pentyl, very particularly preferably propyl.

The compounds of the formula VII are preferably selected from the following sub-formulas:

wherein R ° and X ° have the meanings given above.

R ° preferably denotes alkyl having 1 to 6 carbon atoms. X ° preferably denotes F, furthermore OCF3, OCFIF ₂ and OCFI = CF ₂ .

The LC medium additionally contains one or more compounds of the following formula: wherein R °, X ° and Y ^1-4 each independently have one of the meanings given above. X ° preferably denotes F, CI, CF3, OCF3 or OCFIF2. R ° preferably denotes alkyl, alkoxy, oxaalkyl or fluoroalkyl, each with 1 to 6 carbon atoms.

The LC medium according to the invention particularly preferably contains one or more compounds of the formula IXa, where R ° has the meaning given above. R ° preferably denotes straight-chain alkyl, in particular ethyl, n-propyl, n-butyl or n-pentyl, particularly preferably n-propyl.

The compound (s) of the formula IX, in particular of the formula IXa, is (are) preferably present in the LC medium according to the invention in a concentration of 1-15% by weight, particularly preferably 2-10% by weight.

The LC medium additionally contains one or more compounds of the formula X:

Y ¹

X

R ° - (HW ₀ Vx °

.2

Y wherein R °, X °, Y ¹ and Y ^{2 have} the meanings given above, and R ° is preferably alkyl having 1 to 6 carbon atoms.

The LC medium according to the invention particularly preferably contains one or more compounds of the formula Xa, in which "alkyl" has the meaning given in formula IA1 and preferably denotes ethyl, propyl or pentyl, very particularly preferably propyl.

The compound (s) of the formula X, in particular of the formula Xa, is (are) preferably present in the LC medium according to the invention in a concentration of 0.5-10% by weight, particularly preferably 1-5% by weight.

The LC medium additionally contains one or more compounds of the following formula:

wherein R ° and Y ^2-4 each independently of one another have one of the meanings given above. R ° preferably denotes alkyl, alkoxy, oxaalkyl or fluoroalkyl, in each case with up to 6 C atoms.

The LC medium according to the invention particularly preferably contains one or more compounds of the formula Xla, where R ° has the meaning given above. R ° preferably denotes straight-chain alkyl, in particular ethyl, n-propyl, n-butyl or n-pentyl, particularly preferably n-propyl.

The compound (s) of the formula XI, in particular of the formula Xla, is (are) preferably in an LC medium according to the invention in one

Concentration of 1-30 wt.%, Particularly preferably 2-25 wt.%, Very particularly preferably 2-15 wt.%, Contain.

The LC medium additionally contains one or more compounds of the formula XII: in which R ¹ and R ^{2 have} the meanings given in formula IA and are preferably alkyl having 1 to 6 carbon atoms. - The LC medium additionally contains one or more compounds selected from the following formulas:

wherein R ¹ and R ^{2 have} the meanings given in formula IA and LH or F. R ¹ and R ^{2 are} each, independently of one another, alkyl or alkoxy having 1 to 6 carbon atoms.

The LC medium according to the invention particularly preferably contains one or more compounds of the formula XlVa in which "alkyl" and "alkyl ^* " each independently of one another have the meaning given in formula IA1 and preferably mean ethyl, propyl or pentyl, very particularly preferably ethyl or propyl.

The LC medium additionally contains one or more compounds of the formula XVI,

wherein Y ¹ , Y ² , R ¹ and R ^{2 have} the meanings given above.

Particularly preferred compounds of the formula XVI are those selected from the group of the following sub-formulas: wherein "alkyl" and "alkyl ^* " have the meaning given in formula IA1 and are preferably ethyl, propyl or pentyl.

The compounds of the formulas XVIb are preferred. The compounds are particularly preferably selected from the following sub-formulas

Compounds of the formulas XVIbl, XVIb2 and XVIb3 are particularly preferred. The compound (s) of the formula XVI, in particular of the formula XVIb, is

(Are) preferably contained in the LC medium according to the invention in a concentration of 2-30% by weight, particularly preferably 2-25% by weight. - The LC medium contains one or more compounds selected from the following formulas:

wherein L, R ¹ and R ^{2 have} the meanings given above and preferably R ¹ and R ² each independently represent alkyl having 1 to 6 carbon atoms. Compounds of the formula XVI 11 in which LF is are particularly preferred. Are particularly preferred

Compounds of formula XVII2 wherein L is F.

The LC medium additionally contains one or more compounds selected from the following formulas: wherein R ° and C ° each independently have one of the meanings given above and Y ^{1 -4} each independently represent H or F. X ° preferably denotes F, CI, CF ₃ , OCF3 or OCHF2. R ° preferably denotes alkyl, alkoxy, oxaalkyl or fluoroalkyl, each with 1 to 6 carbon atoms.

The LC medium particularly preferably contains one or more

Compounds of the formula XXa,

where R ° has the meaning given above. R ° preferably denotes straight-chain alkyl, in particular ethyl, n-propyl, n-butyl or n-pentyl, particularly preferably n-propyl.

The compound (s) of the formula XX, in particular the formula XXa, is (are) preferably present in the LC medium according to the invention in a concentration of 1-15% by weight, particularly preferably 2-10% by weight.

The LC medium according to the invention particularly preferably contains one or more compounds of the formula XXIa,

The compound (s) of the formula XXI, in particular of the formula XXIa, is (are) preferably in the media according to the invention in one Concentration of 1-15 wt.%, Particularly preferably 2-10 wt.% Contain.

The LC medium according to the invention particularly preferably contains one or more compounds of the formula XXIIIa,

The compound (s) of the formula XXIII, in particular of the formula XXIIIa, is (are) preferably in an LC medium according to the invention in one

Contain concentration of 0.5-5 wt.%, Particularly preferably 0.5-2 wt.%.

The LC medium additionally contains one or more compounds of the formula XXIV,

wherein R ° and Y ^{1 6 have} the meanings given above, s means 0 or 1, X ° has the meaning given above or alkyl or alkoxy, preferably straight-chain, with 1 -6 carbon atoms, and means.

R ° preferably denotes alkyl having 1 to 6 carbon atoms. X ° preferably denotes F;

The compounds of the formula XXIV are preferably selected from the following sub-formulas:

wherein R °, X ° and Y ^{1 have} the meanings given above. R ° preferably denotes alkyl having 1 to 6 carbon atoms. X ° is preferably F, and Y ¹ is preferably F;

R ° is straight-chain alkyl or alkenyl with 2 to 6 carbon atoms;

wherein R ¹ and X ° have the meanings given above. R ¹ preferably denotes alkyl having 1 to 6 carbon atoms. X ° preferably denotes F or CI. In the formula XXIV, X ° preferably denotes CI.

wherein R ¹ and X ° have the meanings given above. R ¹ preferably denotes alkyl having 1 to 6 carbon atoms. X ° preferably means F.

The LC medium preferably contains one or more

Compounds of the formula XXIX in which X is F.

The compounds of the formulas XXVI-XXIX are preferably present in the LC medium according to the invention in a concentration of 1-20% by weight, particularly preferably 1-15% by weight.

The LC medium preferably contains at least one compound of the formula XXIX.

The LC medium according to the invention particularly preferably contains one or more compounds of the formula XXIXa,

wherein R ^{1 has} the meaning given above. R ¹ preferably denotes straight-chain alkyl, in particular ethyl, n-propyl, n-butyl or n-pentyl, particularly preferably n-propyl.

The compound (s) of the formula XXIX, in particular of the formula XXIXa, is (are) preferably present in the LC medium according to the invention in a concentration of 1-15% by weight, particularly preferably 2-10% by weight. The LC medium additionally contains one or more compounds selected from the following formulas

The LC medium preferably contains one or more

Compounds of the formula XXX1 in which X denotes F.

The compound (s) of the formulas XXX1 -XXX3 is (are) preferably present in the LC medium according to the invention in a concentration of 1-20% by weight, particularly preferably 1-15% by weight. The LC medium according to the invention contains no compounds of the formula IA or IB in which R ¹ and / or R ^{2 are} alkenyl, alkenyloxy, oxaalkenyl or

Fluoroalkenyl with 1 to 8 carbon atoms. The LC medium according to the invention preferably contains no compounds of the formula IA or IB in which R ¹ and / or R ^{2 is} an optionally fluorinated alkyl, alkoxy or

Oxaalkylrest with a C = C double bond means. In a particularly preferred embodiment, the LC medium according to the invention contains no compounds selected from the group consisting of the following formulas, in which L, R ¹ and R ^{2 have} the meanings given above and in which at least one of the radicals R ¹ and R ^{2 has} a C = C - Contains double bond

Other preferred media are selected from the following preferred

Execution forms including all their sub-combinations:

The LC medium contains one or more compounds of the formula II, preferably selected from the group consisting of the formulas 111, II2 and II3, particularly preferably from formulas 111 and II2. The individual concentration of each of these compounds is

preferably 2 to 15% by weight. The total concentration of this

Compounds is preferably 5 to 45% by weight.

- The LC medium contains one or more compounds of the formula III, preferably selected from the group consisting of the formula 1111, III4, III6, 11116, 11119 and III20, particularly preferably from the group consisting of the formula 1111, III6, II 116 and III20. The individual

The concentration of each of these compounds is preferably 2 to 15% by weight. The total concentration of these compounds is preferably from 5 to 30% by weight.

The LC medium contains one or more compounds of the formula IV, preferably selected from formula IVa or IVc, particularly preferably from formula IVa1 or IVc1, very particularly preferably of the formula IVc1. The individual concentration of each of these compounds is preferably 2 to 15% by weight. The total concentration of this

Compounds is preferably 5 to 20% by weight.

- The LC medium contains one or more compounds of the formula V, particularly preferably of the formula Va, very particularly preferably of the formula Va1. The individual concentration of each of these compounds is preferably 1 to 20% by weight. The total concentration of these compounds is preferably 5 to 20% by weight.

The LC medium contains one or more compounds of the formula VI, particularly preferably selected from the formulas Vlb and Vle, very particularly preferably from the formulas Vlb1 and Much. The individual concentration of each of these compounds is preferably 1 to 20% by weight. The total concentration of these compounds is preferably 5 to 20% by weight.

The LC medium contains one or more compounds of the formula XIII, particularly preferably of the formula XI III. The total concentration of these compounds is preferably 1 to 20% by weight.

The LC medium contains one or more compounds of the formula XIV, particularly preferably of the formula XlVa. The individual

The concentration of each of these compounds is preferably 2 to 15% by weight. The total concentration of these compounds is preferably 5 to 20% by weight.

The LC medium contains one or more compounds of the formula X, particularly preferably of the formula Xa. The individual concentration of each of these compounds is preferably 1 to 10% by weight. The

The total concentration of these compounds is preferably 2 to 15% by weight.

The LC medium contains one or more compounds of the formula XI, particularly preferably of the formula Xla. The individual concentration of each of these compounds is preferably 5 to 25% by weight. The

The total concentration of these compounds is preferably 10 to 35% by weight.

The LC medium contains one or more compounds of the formula XVIb, particularly preferably selected from the formulas XVIbl, XVIb2 and XVIb3. The individual concentration of each of these compounds is preferably 2 to 15% by weight. The total concentration of these compounds is preferably 10 to 35% by weight.

The LC medium contains one or more compounds of the formula XVIc, particularly preferably selected from the formulas XVIc1, XVIc2 and XVIc3. The individual concentration of each of these compounds is preferably 2 to 10% by weight. The total concentration of these compounds is preferably 5 to 20% by weight.

The LC medium contains one or more compounds selected from the group consisting of the formulas XVI11, XVII2 and XVII3, particularly preferably of the formula XVI 11 in which L is F and / or the formula XVII2 in which L is F. The individual concentration of each of these compounds is preferably 1 to 8% by weight. The

The total concentration of these compounds is preferably 2 to 10% by weight.

The LC medium contains one or more compounds of the formula XX, particularly preferably of the formula XXa. The individual concentration of each of these compounds is preferably 2 to 10% by weight. The total concentration of these compounds is preferably 2 to 20% by weight.

The LC medium contains one or more compounds of the formula XXI, particularly preferably of the formula XXIa. The individual

The concentration of each of these compounds is preferably 2 to 10% by weight. The total concentration of these compounds is

preferably 3 to 15% by weight.

The LC medium contains one or more compounds of the formula XXIII, particularly preferably of the formula XXIIIa. The concentration of these compounds is preferably 0.5 to 5% by weight.

The LC medium contains one or more compounds of the formula XXIX, particularly preferably of the formula XXIXa. The concentration of these compounds is preferably 2 to 10% by weight.

The LC medium contains one or more compounds of the formula IA, one or more compounds of the formula IB, one or more compounds selected from the group consisting of formulas II and III or their sub-formulas, preferably selected from the group consisting of formulas 111 , II2, II3, 1111, III4, III6, 11116, 11119 and III20, one or more compounds selected from the group consisting of the formulas IV to XI and XVIII to XXX3, preferably selected from the group consisting of the formulas IV, V, VI, VII, X, XI, XX, XXI and XXIII or their sub-formulas and one or more compounds selected from the group consisting of the formulas XII to XVI 13, preferably selected from the group consisting of the formulas XIII, XIV, XVI, XVII1 and XVII2 or their sub-formulas.

- The concentration of the compounds of the formulas II-XI and XVIII-XXX3 in the LC medium according to the invention is 30 to 60% by weight.

- The concentration of the compounds of the formulas XII-XVII3 in

LC medium according to the invention is 2 to 30% by weight.

It has been found that the use of LC media according to the invention which contain one or more compounds of the formulas IA and IB in a mixture with customary liquid crystal materials, but in particular with one or more compounds of the formulas II to XXX3, and do not contain any alkenyl compounds considerable increase in light stability and leads to relatively high values for birefringence, while at the same time broad nematic phases with deep transitions

temperatures can be observed smectically-nematically, which makes the

Storage stability is improved. At the same time, the mixtures show very low threshold voltages and very good values for the VHR under UV exposure and very high clearing points.

The compounds of the formulas IA to XXX3 have a broad range

Scope of application. Depending on the choice of the substituents, they can serve as base materials, from which liquid-crystalline media are predominantly composed; but it can also the compounds of the formulas IA to XXX3 other liquid crystalline

Base materials from other classes of compounds are added, for example, to influence the dielectric and / or optical anisotropy of such a dielectric and / or to optimize its threshold voltage and / or its viscosity.

By a suitable choice of the meanings of R ° and X °, the

Response times, the threshold voltage, the steepness of the transmission characteristics etc. can be modified in the desired manner. The

Mixtures according to the invention are particularly notable for high De values and thus have significantly faster switching lines than the mixtures from the prior art.

In a particularly preferred embodiment, the media according to the invention contain compounds of the formulas II to VIII (preferably II, III, V and VI), in which X ° F, OCF ₃ , OCHF ₂ , OCH = CF ₂ , OCF = CF ₂ or OCF ₂ -CF ₂ FI, particularly preferably F or OCF ₃ .

The compounds of the formulas IA to XXX3 have relatively low

Melting points, show good phase behavior, are colorless in the pure state and form liquid-crystalline mesophases in one for the

electro-optical use conveniently located temperature range.

They are stable chemically, thermally and against light. The optimal quantitative ratio of the compounds of the above-mentioned formulas largely depends on the desired properties, on the choice of components of the above-mentioned formulas and on the choice of further components which may be present. Suitable proportions within the range given above can easily be determined from case to case.

The total amount of compounds of the above formulas in the mixtures according to the invention is not critical. The mixtures can therefore contain one or more other components for the purpose

Optimization of various properties. However, the observed effect on the desired improvement in the properties of the mixture is generally greater the higher the total concentration of compounds of the above formulas.

The individual compounds of the formulas mentioned above and their sub-formulas which can be used in the media according to the invention are either known, or they can be prepared analogously to the known compounds by methods known per se, as described in the literature (for example in the standard works such as Houben-Weyl, Methods of Organic Chemistry, Georg-Thieme-Verlag, Stuttgart) are, and under reaction conditions that for the above

Implementations are known and suitable. Use can also be made of variants which are known per se and are not mentioned here in detail. The mixtures according to the invention can also be polymerizable

Compounds, so-called reactive mesogens (RMs), for example as disclosed in US Pat. No. 6,861,107, are added in concentrations of preferably 0.12-5% by weight, particularly preferably 0.2-2%, based on the mixture. These mixtures can optionally also have one

Contain polymerization initiator, as described, for example, in US Pat. No. 6,781,665. The polymerization initiator, e.g. Irgacure®651 (BASF) is preferably added to the mixture containing polymerizable compounds in amounts of 0 to 1%. Such mixtures can be used for so-called polymer stabilized (PS) modes in which one

Polymerization of the reactive mesogens in the liquid crystalline mixture should be used, e.g. for PS-IPS-, PS-FFS, PS-TN, PS-VA- IPS. The prerequisite for this is that the liquid crystal mixture itself does not contain any polymerizable components. In a preferred embodiment of the invention, the

polymerizable compounds selected from the compounds of formula M.

R ^a -B ¹ - (Z ^b -B ² ) _m -R ^b M in which the individual radicals, each independently and each time the same or different, have the following meaning:

R ^a and R ^b P, P-Sp-, H, F, CI, Br, I, -CN, -N0 ₂ , -NCO, -NCS, -OCN, -SCN,

SF ₅ or straight-chain or branched alkyl with 1 to 25 C-

Atoms in which one or more non-adjacent CFI ₂ groups are each independently of one another by - C (R °) = C (R ⁰⁰ ) -, -C = C-, -N (R ⁰⁰ ) -, -O-, - S-, -CO-, -CO-O-,

-O-CO-, -O-CO-O- can be replaced so that O and / or S atoms are not directly linked to each other, and in which one or more Fl atoms are also replaced by F, CI, Br, I , CN, P or P-Sp-- can be replaced, and in which, if B ¹ and / or B ² contain a saturated C atom, R ^a and / or R ^{b can} also mean a radical which is linked to this saturated C atom via a spiro Linkage can be connected, wherein at least one of the radicals R ^a and R ^{b is} a group P or

P-Sp- means or contains

P a polymerizable group,

Sp a spacer group or a single bond,

B ¹ and B ^{2 are} aromatic, heteroaromatic, alicyclic or

heterocyclic group, preferably with 4 to 25 ring atoms, preferably carbon atoms, which also fused

Rings or can contain rings, and which can optionally be substituted one or more times by L,

L P, P-Sp-, OH, CH2OH, F, CI, Br, I, -CN, -NO2, -NCO, -NCS,

-OCN, -SCN, -C (= 0) N (R ^x ) ₂ , -C (= 0) Y ¹ , -C (= 0) R ^x , -N (R ^x ) ₂ , optionally substituted silyl, optionally substituted aryl with 6 to 20 C atoms, or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonlyoxy or alkoxycarbonyloxy with 1 to 25 C atoms or alkenyl or alkynyl with 2 to 25 C atoms, in which also one or more H- Atoms can be replaced by F, CI, P or P-Sp-, preferably P, P-Sp-, H, OH, CH2OH, halogen, SF5, NO2, an alkyl, alkenyl or alkynyl group, Y ¹ halogen, preferably F,

Z ^b -0-, -S-, -CO-, -CO-O-, -OCO-, -O-CO-O-, -0CH2-, -CH2O-

, -SCH2-, -CH2S-, -CF2O-, -0CF2-, -CF2S-, -SCF2-, - (CH ₂ ) m-, -CF2CH2-, -CH2CF2-, - (CF ₂ ) m-, - CH = CH-, -CF = CF-, -C = C-, -CH = CH-, -COO-, -OCO-CH = CH-, CR ° R ⁰⁰ or one

Single bond, R ° and R ^{00 are} each independently of one another H or alkyl having 1 to 12 carbon atoms, R ^x P, P-Sp, H, halogen, straight-chain, branched or

cyclic alkyl having 1 to 25 carbon atoms, in which one or more non-adjacent CH2 groups are also represented by -0-, -S-,

-CO-, -CO-O-, -O-CO-, -O-CO-O- can be replaced so that 0 and / or S atoms are not directly linked to each other, and in which one or more H -Atoms by F, CI, P or

P-Sp- can be replaced, an optionally substituted aryl or aryloxy group with 6 to 40 C atoms, or an optionally substituted heteroaryl or heteroaryloxy group with 2 to 40 C atoms, m 0, 1, 2, 3 or 4, n1 1, 2, 3 or 4. Preferred compounds of the formula M are those in which B ¹ and B ² , each independently of one another, selected from the group consisting of 1,4-phenylene, naphthalene-1,4-diyl, naphthalene-2, 6-diyl, phenanthrene-2,7-diyl, anthracene-2,7-diyl, fluorene-2,7-diyl, coumarin, flavone, it being possible for one or more CH groups in these groups to be replaced by N, cyclohexane -1, 4-diyl, in which one or more non-adjacent CH2 groups can also be replaced by 0 and / or S, 1, 4-cyclohexenylene, bicyclo [1 .1 .1] pentane-1, 3-diyl, Bicyclo [2.2.2] octane-1,4-diyl, spiro [3.3] heptane-2,6-diyl, piperidine-1,4-diyl, decahydronaphthalene-2,6-diyl, 1, 2,3,4- Tetrahydronaphthalene-2,6-diyl, indane-2,5-diyl or octahydro-4,7-methano-indane-2,5-diyl, all of which these groups can be unsubstituted or substituted one or more times by L.

Particularly preferred compounds of the formula M are those in which B ¹ and B ^{2 are} each independently 1, 4-phenylene, 1, 3-phenylene, naphthalene-1, 4-diyl or naphthalene-2,6-diyl. Further particularly preferred compounds of the formula M are those in which one or both radicals R ^a and R ^{b are} P or P-Sp-.

Particularly preferred compounds of the formula M are selected from the following formulas:

-62 -

35 where the individual radicals have the following meaning:

P ¹ to P ^{3 are} each independently polymerizable

Group, preferably with one of the meanings given above and below for P, particularly preferably an acrylate, methacrylate, fluoroacrylate, oxetane, vinyloxy or epoxy group, Sp ¹ to Sp ³ each independently of one another are a single bond or a spacer group, preferably with one of the meanings given above and below for Sp, and particularly preferably - (CF jp-i-, - (CF jp-iO-, - (CF jp -i-CO-O- or - (Ch jp-iO-CO-O-, in which p1 is an integer from 1 to 12, and in the latter groups the linkage to the adjacent ring takes place via the O atom, where one of the radicals P ¹ -Sp ¹ -, P ² -Sp ² - and P ³ -Sp ³ - can also mean R ^aa ,

R aa H, F, CI, CN or straight-chain or branched alkyl having 1 to 25 C atoms, in which one or more non-adjacent CF groups are each independently of one another by C (R °) = C (R ⁰⁰ ) -, - C = C-, -N (R °) -, -0-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- can be replaced so that 0 and / or S atoms are not directly linked to one another, and in which one or more H atoms can also be replaced by F, CI, CN or P ¹ -Sp ¹ -, particularly preferably straight-chain or branched, optionally one or polyfluorinated, alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, or alkylcarbonyloxy with 1 to 12 carbon atoms (the alkenyl and alkynyl radicals having at least two and the branched radicals having at least three carbon atoms), R ° and R ° ° independently of each other and at every occurrence

the same or different Fl or alkyl with 1 to 12 carbon atoms,

R ^y and R ^z each independently of one another are Fl, F, CFI ₃ or CF ₃ , Z ¹ -0-, -CO-, -C (R ^y R ^z ) -, or -CF2CF2-,

Z ² and Z ³ each independently of one another -CO-O-, -O-CO-, -CFI2O-,

-OCFI2-, -CF2O-, -OCF2-, or - (CFl2) n-, where n is 2, 3 or 4,

L is the same or different in each occurrence and has the meaning given above under formula M and preferably F, CI, CN, or straight-chain or branched, optionally single or multiple fluorinated, alkyl, alkoxy, alkenyl, alkynyl,

Alkylcarbonyl, alkoxycarbonyl, or alkylcarbonyloxy having 1 to 12 carbon atoms, preferably F,

L 'and L "each independently of one another H, F or CI,

X ¹ to X ³ each independently of one another -CO-O-, -O-CO- or one

Single bond, r 0, 1, 2, 3 or 4, s 0, 1, 2 or 3,

0, 1 or 2, and x 0 or 1.

The polymerizable compounds of the formulas M2, M13, M17, M22, M23, M24 and M30 are preferred. Compounds of the formulas M2 and M13 are particularly preferred.

Also preferred are trireactive compounds of the formulas M15 to M31, in particular M17, M18, M19, M22, M23, M24, M25, M30 and M31.

Other suitable and preferred polymerizable compounds are listed, for example, in Table E.

In the compounds of the formulas M1 to M31, the group means

wherein L, the same or different on each occurrence, has one of the meanings given above and below, and preferably F, CI, CN, NO ₂ , CH ₃ , C2H5, C (CH ₃ ) 3, CH (CH ₃ ) 2, CH ₂ CH (CH ₃ ) C2H ₅ , OCH _3I OC2H5, COCH ₃ , COC2H5, COOCHs, COOC2H5, CF ₃ , OCF ₃ , OCHF ₂ , OC2F5 or P- Sp-, particularly preferably F, CI, CN, CH ₃ , C ₂ H ₅ , OCFI ₃ , COCFI ₃ , OCF ₃ or P-Sp-, very particularly preferably F, CI, CH ₃ , OCFI ₃ , COCFI ₃ or OCF ₃ , in particular F or CH ₃ . Preferred compounds of the formulas M1 to M31 are those in which P ¹ , P ² and P ^{3 represent} an acrylate, methacrylate, oxetane or epoxy group, particularly preferably an acrylate or methacrylate group.

Further preferred compounds of the formulas M1 to M31 are those in which Sp ¹ , Sp ² and Sp ^{3 represent} a single bond.

Further preferred compounds of the formulas M1 to M31 are those in which at least one of the radicals Sp ¹ , Sp ² and Sp ^{3 is} a single bond and at least one of the radicals Sp ¹ , Sp ² and Sp ³ is different from a single bond.

Further preferred compounds of the formulas M1 to M31 are those in which those radicals Sp ¹ , Sp ² and Sp ³ which differ from a single bond mean - (CF js-iX "-, in which s1 is an integer from 1 to 6, preferably 2, 3, 4 or 5, and X "represents the link to the adjacent benzene ring and means -0-, -O-CO-, -CO-O-, -O-CO-O- or a single bond.

The LC medium preferably contains one, two or three polymerizable compounds of the formula M, preferably selected from the formulas M1 to M31, particularly preferably selected from Table E.

The liquid-crystalline media according to the present application preferably contain a total of 0.01 to 3%, preferably 0.1 to 1.0%, particularly preferably 0.1 to 0.5%, of polymerizable compounds. It has been observed that the addition of one or more

polymerizable compounds, such as selected from formula M or Table E, leads to advantageous properties such as, for example, faster switching times for the LC medium according to the invention. An LC medium according to the invention containing one or more such polymerizable compounds is particularly suitable for use in PSA displays, in which it has advantageous properties such as reduced image sticking, faster and more complete polymerization, rapid tilt angle generation, increased tilt stability after UV exposure, high reliability, high VFIR values after UV exposure, and high

Can cause birefringence. By appropriate selection of the

polymerizable compounds can also shift the UV absorption to longer wavelengths, so that polymerization is possible at longer UV wavelengths, which is advantageous for the

Production process of the advertisements according to the invention is.

The polymerizable group P is a group which is for a

Polymerization reaction, such as free-radical or ionic chain polymerization, polyaddition or polycondensation, or for a polymer-analogous reaction, for example addition or condensation to a main polymer chain, is suitable. Groups for chain polymerization are particularly preferred, in particular those containing a C =C double bond or —C ^C triple bond, and groups suitable for polymerization with ring opening, such as, for example, oxetane or

Epoxy groups

CO-, HO-CWW-, HS-CWW-, HW ² N-, HO-CWW-NH-, CH ₂ = CW ¹ -CO- NH-, CH ₂ = CH- (C00) ki-Phe- (0 ) _k2 -, CH ₂ = CH- (C0) _ki -Phe- (0) _k2 -, Phe- CH = CH-, HOOC-, OCN- and W ⁴ W ⁵ W ⁶ Si-, where W ¹ H, F , CI, CN, CF ₃ ,

Phenyl or alkyl with 1 to 5 carbon atoms means, in particular H, F, CI or CH ₃ , W ² and W ³ each independently of one another Fl or alkyl with 1 to 5 carbon atoms, in particular Fl, methyl, ethyl or n- Are propyl, W ⁴ , W ⁵ and W ⁶ each independently mean CI, oxaalkyl or oxacarbonylalkyl with 1 to 5 C atoms, W ⁷ and W ⁸ each independently represent Fl, CI or alkyl with 1 to 5 C atoms, Phe 1, 4-phenylene, which is optionally substituted with one or more L radicals other than P-Sp as defined above, ki, k ₂ and k ₃ each independently represent 0 or 1, Wz preferably 1, and WA represents an integer from 1 to 10.

Particularly preferred groups P are CH ₂ = CW ¹ -COO-, in particular

CH ₂ = CH-COO-, CH ₂ = C (CH ₃ ) -COO- and CH ₂ = CF-COO-, furthermore CH ₂ = CH-0-,

Very particularly preferred groups P are vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxy, in particular acrylate and methacrylate.

If Sp is different from a single bond, it is preferably selected from the formula Sp'-X ', so that the remainder P-Sp- corresponds to the formula P- Sp'-X'-, where

Sp 'denotes alkylene having 1 to 20, preferably 1 to 12, carbon atoms,

which is optionally mono- or polysubstituted by F, CI, Br, I or CN, and in which one or more non-adjacent CH ₂ groups are each independently of one another by -O-, -S-, -NFH-, -NR ° -, -SiR °° R ⁰⁰⁰ -, -CO-, -COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, - NR ⁰⁰ -CO-O-, -O-CO-NR ⁰⁰ -, -NR °° -CO-NR ⁰⁰ -, -CH = CH- or -C = C- can be replaced that 0 and / or S atoms are not directly

are linked together

X '-0-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR ⁰⁰ -, -NR ⁰⁰ -CO-, - NR ⁰⁰ -CO-NR ⁰⁰ -, -OCH2-, -CH ₂ 0-, -SCH ₂ -, -CH ₂ S-, -CF ₂ 0-, -OCF ₂ -, -

CF ₂ S-, -SCF ₂ -, -CF ₂ CH ₂ -, -CH ₂ CF ₂ -, -CF ₂ CF ₂ -, -CH = N-, -N = CH-, -

N = N-, -CH = CR ° -, -CY ² = CY ³ -, -C = C-, -CH = CH-COO-, -OCO-CH = CH- or a single bond means R ⁰⁰ and R °°° independently of one another Fl or alkyl with 1 to 12 C-

Atoms mean and

Y ² and Y ³ each independently mean Fl, F, CI or CN. is preferably -0-, -S -CO-, -COO-, -OCO-, -O-COO-, -CO-NR ⁰ -, -NR ° - CO-, -NR ° -CO-NR ° - or a single bond.

Typical spacing groups Sp 'are, for example - (CFH ₂ ) _PI -, - (CFH ₂ CFH ₂ 0) _qi - CH ₂ CH ₂ -, -CH ₂ CH ₂ -S-CH ₂ CH ₂ -, -CH ₂ CH ₂ - NH-CH ₂ CH ₂ - or - (SiR ⁰⁰ R ⁰⁰⁰ -O) _Pi -, where p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R ⁰⁰ and R ⁰⁰⁰ are those given above Have meanings.

Particularly preferred groups Sp and -Sp “-X” - are - (CFH ₂ ) _PI -, - (CFH ₂ ) _pi -0-, - (CFI ₂ ) pi-0-C0-, - (CFI ₂ ) pi- C0-0-, - (CFI ₂ ) pi-0-C0-0-, wherein p1 and q1 have the meanings given above.

Particularly preferred groups Sp 'are, for example, in each case

straight-chain ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene,

Ethyleneoxyethylene, methyleneoxybutylene, ethylene thioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene, ethenylene, propenylene and

Butenylene.

In a further preferred embodiment of the invention, P- Sp- is a radical with two or more polymerizable groups

(multifunctional polymerizable residues). Suitable residues of this type, as well as polymerizable compounds containing them and their Production is described for example in US 7,060,200 B1 or US 2006/0172090 A1. Multifunctional ones are particularly preferred

polymerizable residues P-Sp- selected from the following formulas -X-alkyl-CHP ¹ -CH ₂ -CH ₂ P ² l ^* a

-X-alkyl-C (CH ₂ P ¹ ) (CH ₂ P ² ) -CH ₂ P ³ l ^* b

-X-alkyl-CHP ¹ CHP ² -CH ₂ P ³ l ^* c

-X-alkyl-C (CH ₂ P ¹ ) (CH ₂ P ² ) -C _aa H ₂ aa + il ^* d

-X-alkyl-CHP ¹ -CH ₂ P ² l ^* e -X-alkyl-CHP ¹ P ² l ^* f

-X-alkyl-CP ¹ P ² -CaaH _2a a _{+ i} l ^* g

-X-alkyl-C (CH ₂ P ¹ ) (CH ₂ P ² ) -CH ₂ OCH ₂ -C (CH ₂ P ³ ) (CH ₂ P ⁴ ) CH ₂ P ⁵ l ^* h

-X-alkyl-CH ((CH ₂ ) aaP ¹ ) ((CH ₂ ) bbP ² ) l ^* i

-X-alkyl-CHP ¹ CHP ² -C _aa H ₂ aa + il ^* k -X'-alkyl-C (CH ₃ ) (CH ₂ P ¹ ) (CH ₂ P ² ) l ^* m wherein alkyl is a single bond or straight-chain or branched alkylene having 1 to 12 carbon atoms, in which one or more non-adjacent CH ₂ groups each independently of one another by -C (R °°) = C (R ⁰⁰⁰ ) -, -C = C-, -N (R ⁰⁰ ) -, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- can be replaced so that O- and / or S- Atoms are not directly linked to one another, and in which one or more H atoms can also be replaced by F, CI or CN, where R °° and R °°° have the meaning given above, aa and bb each independently represent 0, 1, 2, 3, 4, 5 or 6,

X has one of the meanings given for X ', and

P ^{1 5} each independently of one another of those specified for P.

Have meanings.

The polymerizable compounds and RMs can be prepared analogously to the processes known to the person skilled in the art and described in standard works of organic chemistry, such as, for example, in Houben-Weyl, Methods of Organic Chemistry, Thieme-Verlag, Stuttgart. Further synthetic methods can be found in the documents cited above and below. In the simplest case, such RMs are synthesized, for example, by esterification or etherification of 2,6-dihydroxynaphthalene or 4,4'-dihydroxybiphenyl with corresponding acids, acid derivatives, or halogenated compounds containing a group P, such as (meth) acrylic acid chloride or ( Meth) acrylic acid, in the presence of a dehydrating reagent such as DCC (dicyclohexylcarbodiimide).

To freeze PSA displays according to the invention, the polymerizable ones contained in the LC medium according to the invention become

Compounds polymerized or crosslinked, preferably in situ in the display, with a voltage optionally being applied to the electrodes of the display.

The structure of the LC displays according to the invention corresponds to the geometry customary for PSA displays, as described in the prior art cited at the beginning. Geometries without protrusions are preferred, in particular those in which the electrode on the color filter side is also unstructured and only the electrode on the TFT side has slots. Particularly suitable and preferred

Electrode structures for PS-VA displays are described, for example, in US 2006/0066793 A1. The LC mixtures and LC media according to the invention are suitable in principle for any type of PS or PSA display, in particular those based on LC media with negative dielectric anisotropy, particularly preferably for PSA-VA-, PSA-IPS- or PS- FFS ads. However, the person skilled in the art can, without inventive step, use suitable LC mixtures and LC media according to the invention in other displays of the PS or PSA type, for example in PS-TN or PS-OCB displays, which differ from those mentioned above Displays, for example, by their basic structure or by the type, arrangement or structure of the individual components used, such as the substrates,

Orientation layers, electrodes, control elements,

Backlight, polarizers, color filters, if any

Differentiate between compensation foils etc. In a further preferred embodiment, the

LC medium according to the invention comprises one or more chiral dopants, preferably in a concentration of 0.01 to 1% by weight, particularly preferably of 0.05 to 0.5% by weight. The chiral dopants are

preferably selected from the group consisting of the

Compounds in Table B below, particularly preferably from the group consisting of R- or S-1011, R- or S-2011, R- or S-3011, R- or S-4011, and R- or S-5011.

In a further preferred embodiment, the

LC medium according to the invention is a racemate of one or more chiral dopants, preferably selected from the preferred chiral dopants mentioned above.

In a further preferred embodiment, the

LC medium according to the invention a "self-alignment" (SA) additive,

preferably in a concentration of 0.1 to 2.5% by weight. Such media are particularly suitable for use in SA-FFS or SA-FIB-FFS displays, which can also be polymer-stabilized. In a preferred embodiment, the SA-FFS or SA-HB-FFS display contains no orientation layers, in particular no polyimide orientation layers. SA additives are preferably selected from compounds containing a mesogenic group and a straight-chain or branched alkyl side chain which has a terminal polar anchor group which is preferably selected from the group consisting of flydroxy, carboxy, amino and thiol groups.

Other preferred SA additives contain in addition to the polar one

Anchor group one or more polymerizable groups which are linked to the mesogenic group, optionally via spacer groups. These polymerizable SA additives can be used in the LC medium under the same or similar conditions as the polymerizable ones mentioned above

Compounds or RMs are polymerized.

Suitable and preferred SA additives are, for example, in US

2013/0182202 A1, US 2014/0838581 A1, US 2015/0166890 A1 and US 2015/0252265 A1.

Further suitable and preferred SA additives are selected from Table F below. The present invention also relates to the use of the mixtures according to the invention in electro-optical displays and the use of the mixtures according to the invention in LC windows, shutter glasses, in particular for 3D applications, and in TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, PS-FFS, posi-VA and PS-posi-VA displays.

Another object of the invention is an electro-optical display, a FK window, shutter glasses for 3D applications, and a FK display of the TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, PS-FFS, posi-VA or posi-PS-VA type, containing an LC medium according to the invention. The invention also relates to electro-optical displays, such as. B. STN or MFK displays with two plane-parallel carrier plates, which form a cell with a border, integrated non-linear elements for switching individual pixels on the carrier plates and a nematic liquid crystal mixture in the cell with positive dielectric anisotropy and high specific resistance) which contain such media and the use of these media for electro-optical purposes.

The liquid crystal mixtures according to the invention enable a significant expansion of the available parameter space. The achievable combinations of clearing point, viscosity at lower

Temperature, thermal and UV stability and high optical anisotropy far surpass previous materials from the prior art. The mixtures according to the invention are especially for mobile

Applications and TFT applications, such as B. mobile phones and PDAs. The mixtures according to the invention can also be used in FFS, IPS, OCB and IPS displays. The liquid crystal mixtures according to the invention make it possible, while maintaining the nematic phase up to -20 ° C and preferably up to -30 ° C, particularly preferably up to -40 ° C, and the clearing point> 70 ° C, preferably> 72 ° C, rotational viscosities gi of <110 mPa-s, particularly preferably <100 mPa-s to achieve, which excellent MFK displays can be achieved with fast switching times. The

Rotational viscosities are determined at 20 ° C.

The dielectric anisotropy of the liquid crystal mixtures De according to the invention is preferably> +7, particularly preferably> +8, particularly preferably> 10 at 20 ° C. The mixtures are also characterized by small operating voltages. The threshold voltage of the liquid-crystal mixtures according to the invention is preferably <2.0 V. The birefringence ie the liquid-crystal mixtures according to the invention is preferably> 0.09, particularly preferably> 0.10 at 20 ° C. The nematic phase range of the liquid crystal mixtures according to the invention is preferably at least 90 °, in particular at least 100 ° wide. This area preferably extends at least from

-25 ° to + 70 ° C.

It is understood that by appropriate selection of the components of the

Mixtures according to the invention can also be used to achieve higher clearing points (e.g. above 100 ° C.) at higher threshold voltages or lower clearing points at lower threshold voltages while maintaining the other advantageous properties. Likewise, with viscosities correspondingly slightly increased, mixtures with a larger de and thus low thresholds can be obtained. The MFK displays according to the invention preferably operate in the first transmission minimum according to Gooch and Tarry [C. H. Gooch and FI.A. Tarry, electron. Lett. 10, 2-4, 1974; C. H. Gooch and FI.A. Tarry, Appl. Phys., Vol. 8, 1575-1584, 1975], where in addition to particularly favorable electro-optical properties, such as e.g. high steepness of the characteristic and low angle dependence of the contrast (DE-PS 30 22 818) with the same threshold voltage as in an analog display in the second minimum, a smaller dielectric anisotropy is sufficient. Flierdurch can be using the

Mixtures according to the invention realize in the first minimum significantly higher specific resistances than with mixtures with cyan

links. The person skilled in the art can, by suitable choice of the individual components and their weight fractions, with simple routine methods, the required for a given layer thickness of the MLC display

Set birefringence.

Measurements of the Voltage Flolding Ratio (FIR) [p. Matsumoto et al. , Liquid Crystals 5, 1320 (1989); K. Niwa et al., Proc. SID Conference, San Francisco, June 1984, p. 304 (1984); G. Weber et al., Liquid Crystals 5, 1381 (1989)] have shown that mixtures according to the invention containing one or more compounds of the formula 1 and one or more compounds of the formula 2 and one or more compounds of the formulas 3 to 5 and one or more compounds of the formulas 6 and / or 7 have a significantly smaller decrease in FIR under UV exposure than analog mixtures, the cyanophenylcyclohexanes of the formula or esters of the formula

contain.

The light stability and UV stability of the mixtures according to the invention is considerably better, i.e. they show a significantly smaller decrease in HR under light or UV exposure.

The construction of the MFK display according to the invention from polarizers, electrode base plates and electrodes with surface treatment corresponds to the design customary for such displays. The concept of the usual design is broad here and also includes all modifications and modifications of the MLC display, in particular also matrix display elements based on poly-Si TFT or MIM.

A significant difference between the displays according to the invention and those previously used on the basis of the twisted nematic cell, however, is the choice of the liquid crystal parameters of the liquid crystal layer.

The liquid-crystal mixtures which can be used according to the invention are prepared in a conventional manner, for example by adding one or more compounds of the formula 1 and one or more compounds of the formula 2 to one or more compounds of the formulas 3 to 5 and one or more compounds of the formula 6 and / or 7 and optionally one or more II to XXVIII or mixed with further liquid-crystalline compounds and / or additives. As a rule, the desired amount is used in a lesser amount

Components dissolved in the components that make up the main constituent, expediently at elevated temperature. It is also possible to dissolve the components in an organic solvent, e.g. in acetone, chloroform or methanol to mix and the solvent after

To remove mixing again, for example by distillation.

The dielectrics can also further additives known to the person skilled in the art and described in the literature, such as, for. B. UV stabilizers such as Tinuvin ^® , eg Tinuvin ^® 770, from Ciba Chemicals, antioxidants, eg TEMPOL, microparticles, radical scavengers, nanoparticles, etc. contain. For example, 0 to 15% pleochroic dyes or chiral dopants can be added. Suitable stabilizers and dopants are listed in Tables C and D below.

In the present application and in the following examples, the structures of the liquid crystal compounds are indicated by acronyms, the transformation into chemical formulas according to Table A taking place. All residues C _n F _{n + i} and C _m F _{m + i} are straight-chain alkyl residues with n or m C atoms; n, m and k are integers and are preferably 0, 1, 2,

3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, particularly preferably 1, 2, 3, 4, 5, 6 or 7. The coding according to Table B goes without saying. In Table A is only the acronym for the body is given. In individual cases, there is a code for the substituents R, R ^{2 *} , U ^* and L ^{2 *} separated from the acronym for the base body:

code

R ^{2 *} , L

nm CnH2n ₊₁ CmH2m ₊₁ HH nOm CnH2n ₊₁ OCmH2m + 1 HH nO.m OCnH2n + 1 CmH2m ₊₁ HH n CnH2n ₊₁ CN HH nN.F CnH2n ₊₁ CN FH nN.FF CnH2n ₊₁ CN FF nF CnH2n ₊₁ FHH nCI CnH2n + 1 CI HH nOF OC _n H2n + 1 FHH nF.F CnH2n + 1 FFH nF.FF CnH2n + 1 FFF nOCFs CnH2n + 1 OCFs HH nOCFs.F CnH2n + 1 OCF 3 FH n-Vm CnH2n + 1 -CH = CH-CrnH ₂ m ₊₁ HH nV-Vm CnH ₂ n + 1-CH = CH- -CH = CH-CrnH ₂ m ₊₁ HH Preferred blend components are shown in Tables A and B.

Table A

Table B

In the following formulas, n and m each independently mean 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, in particular 2, 3, 5, furthermore 0, 4, 6 , preferably not 0.

CWCG-nF

CWCQU-nF

PYP-n-m

Liquid-crystalline mixtures which, in addition to the compounds of the formulas 1 and 2 and (3 to 5) and 6 and / or 7, contain at least one, two, three, four or more compounds from Table B are particularly preferred.

Table C.

Table C shows possible dopants which are generally added to the mixtures according to the invention. Preferably The mixtures contain 0 to 10% by weight, in particular 0.01 to 5% by weight and particularly preferably 0.01 to 3% by weight, of dopants.

R / S-4011 R / S-5011 R / S-1011

Table D

Stabilizers which can be added, for example, to the mixtures according to the invention in amounts of 0 to 10% by weight are mentioned below.

n = 1, 2, 3, 4, 5, 6 or 7



 q = 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10

Table E

Table E lists sample compounds which can preferably be used as reactive mesogenic compounds in the LC media according to the present invention. If the mixtures according to the invention contain one or more reactive compounds, they are preferably used in amounts of 0.01 to 5% by weight. An initiator or a mixture of two or more initiators may have to be added for the polymerization. The initiator or the initiator mixture is preferably added in amounts of 0.001 to 2% by weight, based on the mixture. A suitable initiator is, for example, Irgacure®651 (from BASF). RM-39

RM-40

RM-41

RM-42

RM-43

RM-44

RM-45

RM-46 RM-55

RM-56

RM-57

RM-58

RM-59

RM-60

RM-61

RM-62 RM-111

RM-112

RM-113

RM-114

RM-115

RM-116 In a preferred embodiment, the LC medium according to the invention contains one or more polymerizable compounds from Table E, preferably selected from the polymerizable compounds of the formulas RM-1 to RM-144, particularly preferably from the formulas 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-1 17, RM-120 , RM-121 and RM-122.

Table F

Table F shows SA additives which can preferably be used in the media according to the invention:

SA-18

SA-19

SA-20

SA-21

SA-25

SA-26

SA-27

SA-28

-

SA-32

SA-33

SA-34

SA-35 In a preferred embodiment, the LC medium according to the invention contains one or more SA additives selected from the formulas SA-1 to SA-44, particularly preferably from the formulas SA-14 to SA-34 and SA-44, very particularly preferably from the Formulas SA-20 to SA-34 and SA-44. The following mixture examples are intended to illustrate the invention without limiting it.

Percentages above and below mean percentages by weight. All temperatures are given in degrees Celsius. Mp. Means melting point, Kp. = Clearing point. Furthermore, K = crystalline state, N = nematic phase, S = smectic phase and I = isotropic phase. The information between these symbols represents the transition temperatures.

Also means

Ie the optical anisotropy at 589 nm and 20 ° C, the rotational viscosity (mPa-s) at 20 ° C, - De the dielectric anisotropy at 20 ° C and 1 khlz (De = em - e ±, where e _|| die Dielectric constant parallel to the longitudinal axes of the molecules and e ± which means dielectric constant perpendicular to it),

V10 the voltage (V) for 10% transmission (viewing direction perpendicular to the plate surface), (threshold voltage), determined in a TN

Cell (90 degrees twist) at the 1st minimum (i.e. at a d-An value of 0.5 pm) at 20 ° C,

Vo the capacitively determined Freedericks threshold voltage in an anti-parallel rubbed cell at 20 ° C.

LTS is the storage or low temperature stability in hours (h), measured in suitable test cells at a temperature of -20 ° C, unless explicitly stated otherwise.

All physical properties are classified according to "Merck Liquid

Crystals, Physical Properties of Liquid Crystals "Status Nov. 1997, Merck KGaA, Germany determines and apply to a temperature of 20 ° C, unless explicitly stated otherwise. Comparative Example 1

CC-3-V 29.4% cl.p. 75.5 ° C

CCP-V-1 20.2% Dh 0.1035 CCP-V2-1 9.0% De +7.1

CPP-2-F 4.1% ^e II 10.4 CPP-3-F 4.0% e _± 4.3 BCH-3F.FF 10.0% gi 61 mPas PUQU-3-F 23.3% Vio 1.53 V

LTS 1000 h

example 1

PUQU-3-F 8.5% cl.p. 72.5 ° C CCQU-2-F 12.0% Dh 0.0985

CCQU-3-F 13.0% De +7.2 CCQU-5-F 10.0% ^e II 10.6 CCGU-3-F 8.0% e _± 3.4 PCH-301 10.5% gi 84 mPas PCH-3CL 3.0% Vio 1.50 V

CCH-23 14.0% LTS 1000 h CCH-34 8.0%

PGP-2-3 4.0%

PGP-2-4 4.0%

PGP-2-5 5.0%

Example 2

CCH-23 16.0% cl _. p _. 74.5 ° C

CCH-34 7.0% Dh 0.0989

PCH-301 17.0% De +6.5

CCH-301 8.0% eii 9.9

PGP-2-3 2.0% e _± 3.4

PGP-2-4 2.0% to 86 mPas

PGP-2-5 2.0% Vio 1.49 V

PGUQU-3-F 8.0% LTS 1000 h CCGU-3-F 5.0%

CCQU-2-F 7.0%

CCQU-3-F 7.0%

CCQU-5-F 6.0%

CBC-33F 2.0%

CPGU-3-OT 6.0%

BCH-3F.F.F 5.0%

Example 3

CCH-23 17.0% cl.p. 74.5 ° C

CCH-34 6.5% Dh 0.0992

PCH-301 15.5% De +7.1

CCH-301 8.5% ^e II 10.7 PGUQU-3-F 9.0% e ± 3.6

CCGU-3-F 5.5% gi 75 mPas CCQU-2-F 5.5% Vio 1.43 V CCQU-3-F 4.0% LTS 1000 h CCQU-5-F 4.0%

CBC-33F 2.0%

CPGU-3-OT 3.5%

CPU-3-OXF 19.0%

Example 4

CCH-23 17.5% cl.p 74.5 ° C

CCH-34 11.5% Dh 0.1014

PCH-301 16.5% De +6.2

CCH-301 9.5% ^e II 9.7 PGUQU-3-F 8.0% e ± 3.5 CCGU-3-F 9.0% gi 76 mPas CBC-33F 2.0% Vio 1.55 V CPGU-3-0T 3.0%

CPU-3-0XF 23.0% Comparative Example 2

CC-3-V 52.0% cl.p. 75.5 ° C

APUQU-3-F 14.0% Dh 0.1187

BCH-32 7.0% De +4.6

GGP-3-CL 2.0% ^e II 7.6

PGP-2-3 9.0% e _± 3.0

PGP-2-4 10.0% to 54 mPas

PGP-2-5 2.0% Vio 1.96 V

PUQU-3-F 4.0% LTS -20 ° 1000 h

LTS -30 ° 168 h

Example 5

BCH-32 5.0% cl.p. 74.0 ° C

PUQU-3-F 6.5% Dh 0.1182

PGP-2-3 6.0% De +4.1

PGP-2-4 6.0% ^e II 7.2

PGP-2-5 8.0% e _± 3.2

CCQU-2-F 2.0% to 66 mPas

CCQU-3-F 5.0% Vio 1.92 V

CCQU-5-F 2.5% LTS -20 ° 1000 h

PCH-301 16.0% LTS -30 ° 1000 h

CCH-301 5.0%

CCH-23 15.5%

CCH-34 1 1 .0%

CPGU-3-0T 4.5%

CCGU-3-F 7.0% Example 6

BCH-32 5.0% cl _. p 74.0 ° C

PUQU-3-F 5.0% Dh 0.1167

PGP-2-3 4.0% De +4.3

PGP-2-4 3.5% _{e ||} 7.5

PGP-2-5 7.5% 3.2 PCH-301 16.0% Yi 67 mPas

CCH-301 3.5% V10 1.91 V

CCH-23 17.5% LTS -20 ° C 1000 h

CCH-34 11.5% LTS -30 ° C 1000 h CCGU-3-F 9.0%

CPU-3-OXF 17.5%

Example 7 PUQU-3-F 7.0% cl.p. 75.0 ° C

PGP-2-3 7.5% Dh 0.1170 PGP-2-4 7.0% De +3.6 PGP-2-5 9.0% ^e II 6.8 CCQU-2-F 4.0% e _± 3.2 CCQU-3-F 4.5% yi 75 mPas

CCQU-5-F 4.0% V10 1.97 V PCH-301 14.0% LTS -20 ° C 1000 h CCH-301 8.0% LTS -30 ° C 1000 h CCH-23 14.5%

CCH-34 10.0%

CCGU-3-F 6.5%

CPGP-4-3 4.0%

Example 8

PGP-2-3 4.5% cl.p. 74.0 ° C PGP-2-4 4.5% Dh 0.1173 PGP-2-5 7.5% De +3.8 PCH-301 15.5% _e „7.1 CCH-301 9.0% _ei 3.3

CCH-23 16.0% _gi 70 mPas CCH-34 9.0% Vio 1.94 V CPGU-3-OT 3.5% LTS -20 ° C 1000 h CPU-3-OXF 19.5% LTS -30 ° C 1000 h CBC-33F 3.5%

PGUQU-3-F 2.0% BCH-3F.FF 5.5%

Example 9

PGP-2-3 5.0% cl.p. 75.0 ° C

PGP-2-4 4.5% Dh 0.1 172

PGP-2-5 6.5% De +3.7

PCH-301 16.0% ^e II 6.9

CCH-301 8.5% e ± 3.3

CCH-23 17.0% to 68 mPas

CCH-34 10.5% Vio 1.99 V

CCGU-3-F 5.5% LTS -20 ° C 1000 h

CPU-3-OXF 20.0% LTS -30 ° C 1000 h

CPGP-4-3 3.0%

PGUQU-3-F 3.5%

Example 10

PGP-2-3 5.5% cl.p. 75.0 ° C

PGP-2-4 5.0% Dh 0.1 167

PGP-2-5 8.0% De +3.7

CCQU-2-F 4.5% ^e II 7.0

CCQU-3-F 4.5% e ± 3.3

CCQU-5-F 4.0% to 70 mPas

PCH-301 15.5% Vio 1.95 V

CCH-301 8.5% LTS -20 ° C 1000 h

CCH-23 15.5% LTS -30 ° C 1000 h

CCH-34 6.0%

CPGU-3-OT 3.0%

CPU-3-OXF 17.5%

CPGP-4-3 2.5%

Comparative Example 3

CC-3-V 30.0% cl.p. 76.0 ° C

CCP-V-1 16.5% Dh 0.1321 GGP-3-CL 5.0% De +6.0

BCH-3F.FF 14.0% ^e II 9.3

PUQU-3-F 15.0% e ± 3.3

PGP-2-3 5.5% to 69 mPas

PGP-2-4 6.0% Vio 1.68 V

PGP-2-5 8.0%

Example 11 BCH-32 5.0% cl.p 75.5 ° C

PUQU-3-F 7.5% Dh 0.1316

PGP-2-3 6.5% De +6.2

PGP-2-4 6.5% ^e II 9.6

PGP-2-5 8.0% e ± 3.4 CCQU-2-F 2.0% gi 86 mPas

CCQU-3-F 3.0% Vio 1.66 V CCQU-5-F 2.5%

PCH-301 17.5%

PCH-3CL 4.5%

CCH-23 13.5%

CCH-34 7.0%

CPGU-3-OT 5.5%

CCGU-3-F 5.5%

PGUQU-3-F 5.5%

Example 12

PGP-2-3 6.0% cl.p 75.0 ° C PGP-2-4 6.0% Dh 0.1317 PGP-2-5 8.5% De +5.4 PCH-301 16.5% ^e II 8.8 CCH-301 7.5% e ± 3.4 CCH- 23 16.0% gi 78 mPas CCH-34 6.5% Vio 1.73 V CPGU-3-OT 3.5%

CPU-3-OXF 18.0% CBC-33F 1.5%

PGUQU-3-F 10.0%

Example 13

0.04% of the following compound is added as a stabilizer to the mixture from Example 1:

Example 14

0.05% of the following compound is added as a stabilizer to the mixture from Example 5:

Example 15

0.03% of the following compound is added as a stabilizer to the mixture from Example 11:

Example 16 0.04% of the following compound is added as a stabilizer to the mixture from Example 2:

Example 17

0.03% of the following compound is added as a stabilizer to the mixture from Example 7:

VHR measurements

To determine the voltage holding ratio (VHR) and its stability after BL stress (BL = backlight), the respective mixture is placed in a test cell with an orientation material for parallel alignment in TN configuration and flat ITO electrodes. Then the VHR of the respective mixture is measured (measuring device: Autronic VHRM 105, signal amplitude: 1 V,

Pulse width 60 ps, measuring frequency 60 Hz, temperature 100 ° C). The corresponding test cells are then exposed to a cold cathode (CCFL) LCD backlight ("backlight") for up to 1,000 hours. According to certain

In each case, the VHR is measured as described above.

A measurement series of 4 test cells is filled and examined for each individual mixture. The values given are the average of the measured individual values. The results are in Table 1

summarized.

Table 1 - VHR values

¹⁾ after 500h

It can be seen from Table 1 that the mixtures according to the invention have a significantly smaller decrease in VFIR after BL stress and thus a significantly higher VHR stability than the comparison mixtures. It can also be seen from the examples given above that the mixtures according to the invention have at least equally good or higher LTS values than the comparative mixtures, in particular at low temperatures (-30 ° C.).

Claims

1 . FK medium, characterized in that it is a positive

has dielectric anisotropy and one or more

Compounds of formula IA and one or more compounds of

Formula IB contains

wherein R ¹ and R ^{2 are} each independently alkyl, alkoxy,

Oxaalkyl or fluoroalkyl, each having 1 to 7 carbon atoms, and the LC medium does not contain any compounds selected from the formulas IA and IB, in which the radicals R ¹ and R ^{2 have} the meaning given above and additionally one or both radicals R ¹ or R ² contain a C = C double bond.

2. LC medium according to claim 1, characterized in that it contains one or more compounds of the formula IA selected from the following sub-formulas

wherein the individual radicals, independently of one another and each time the same or different, have the following meaning alkyl, alkyl ^* straight-chain alkyl with 1 -6 carbon atoms, in particular ethyl, propyl, butyl or pentyl, alkoxy straight-chain alkoxy with 1 -6 carbon atoms, in particular

Methoxy ethoxy or propoxy.

3. LC medium according to claim 1 or 2, characterized in that it contains one or more compounds of the formula IB selected from the following sub-formula

alkoxy IB1

wherein "alkyl" and "alkoxy" are those specified in claim 2

Have meanings.

4. LC medium according to one or more of claims 1 to 3,

characterized in that it contains one or more compounds selected from the following sub-formulas

IB1 b

5. LC medium according to one or more of claims 1 to 4, characterized in that it contains one or more compounds selected from the group consisting of the following formulas

R ° unsubstituted or halogenated alkyl or alkoxy having 1 to 15 carbon atoms, one or more Chh groups in these radicals also being each independently of one another by —CF2O—, - <c> -, -0-, -CO-O- or -O-CO- can be replaced so that O atoms are not directly linked to each other,

X ° F, CI, halogenated alkyl, halogenated alkoxy or

halogenated alkenyloxy with up to 6 C atoms each.

Y ^{1 6} Fl or F,

Y ° H or CH ₃ .

6. LC medium according to one or more of claims 1 to 5, characterized in that it additionally contains one or more compounds selected from the group consisting of the following formulas

wherein R °, X ° and Y ^1-4 each independently have the meanings given in claim 5,

Z ° -C2H4-, - (CH ₂ ) 4-, -CH = CH-, -CF = CF-, -C2F4-, -CH2CF2-, -CF2CH2-, -CFI ₂ O-, -OCFI ₂ -, - COO- or -OCF ₂ -, in formulas V and VI also a single bond, in formulas V and VIII also -CF ₂ O-, r 0 or 1, and s 0 or 1.

7. LC medium according to one or more of claims 1 to 6,

characterized in that it contains one or more compounds of the following formula wherein R °, X ° and Y ^{1 4} each independently have the meanings given in claim 5.

8. LC medium according to one or more of claims 1 to 7,

characterized in that it contains one or more compounds of the following formula

wherein R °, X °, Y ¹ and Y ² each independently in

Claim 5 meanings given.

9. LC medium according to one or more of claims 1 to 8, characterized in that it contains one or more compounds of the following formula

wherein R ° and Y ^2-4 each independently have the meanings given in claim 5.

10. LC medium according to one or more of claims 1 to 9, characterized in that it contains one or more compounds selected from the group consisting of the following formulas

wherein R ¹ and R ² each independently have the meanings given in claim 1 and L is Fl or F.

1 1. LC medium according to one or more of claims 1 to 10, characterized in that it contains one or more compounds of the following formula

wherein R ¹ , R ² , Y ¹ and Y ² each independently have the meanings given in Claims 1 and 5.

12. LC medium according to one or more of claims 1 to 1 1, characterized in that it contains one or more compounds selected from the group consisting of the following formulas wherein L, R ¹ and R ² each independently have the meanings given in claim 10.

13. LC medium according to one or more of claims 1 to 12, characterized in that it contains one or more compounds selected from the group consisting of the following formulas

14. LC medium according to one or more of claims 1 to 13, characterized in that it contains one or more stabilizers selected from the group consisting of the following formulas

R ^a_d straight-chain or branched alkyl having 1 to 10 C atoms,

X ^s H, CH ₃ , OH or 0 ',

A ^s straight-chain, branched or cyclic alkylene with 1 to 20 C atoms which is optionally substituted, n is an integer from 1 to 6.

15. LC medium according to one or more of claims 1 to 14, characterized in that it contains no compounds which contain a C = C double bond, except a C = C double bond as part of a polymerizable group or an aromatic or unsaturated ring .

16. A method for producing an LC medium according to one or more of claims 1 to 15, characterized in that one or more compounds as in one or more of the

Claims 1 to 4 defined are mixed with one or more compounds as defined in one or more of claims 5 to 14.

17. Use of an LC medium according to one or more of claims 1 to 15 for electro-optical purposes.

18. Use according to claim 16 in TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, PS-FFS, posi-VA or PS-posi -VA displays, FK windows or shutter glasses for 3D applications.

19. FK display containing a FK medium after one or

several of claims 1 to 15.

20. FK display according to claim 19, characterized in that there is a TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, PS-FFS, posi-VA or PS-posi-VA displays.