TW202330872A - Liquid-crystal medium - Google Patents

Abstract

The invention relates to a liquid-crystalline medium with negative dielectric anisotropy and to the use thereof for an active-matrix display, in particular based on the VA, SA-VA, IPS, PS-IPS, FFS, PS-FFS, UB-FFS or PS-UB-FFS effect.

Description

liquid crystal medium

The invention relates to liquid-crystalline media with negative dielectric anisotropy and their use, in particular based on the VA, SA-VA, IPS, PS-IPS, FFS, PS-FFS, UB-FFS or PS-UB-FFS effect. Uses for source matrix displays.

Media of this type are used in particular for electro-optic displays with active-matrix addressing based on the ECB effect and for IPS (In-Plane Switching) displays or FFS (Fringe Field Switching) displays.

The principle of electrically controlled birefringence, ECB effect or DAP (Alignment Phase Deformation) effect was first described in 1971 (M.F. Schieckel and K. Fahrenschon, "Deformation of nematic liquid crystals with vertical orientation in electrical fields", Appl. Phys. Lett . 19 (1971), 3912). Later J.F. Kahn (Appl. Phys. Lett. 20 (1972), 1193) and G. Labrunie and J. Robert (J. Appl. Phys. 44 (1973), 4869) published papers.

J. Robert and F. Clerc (SID 80 Digest Techn. Papers (1980), 30), J. Duchene (Displays 7 (1986), 3) and H. Schad (SID 82 Digest Techn. Papers (1982), 244) The paper shows that the liquid crystal phase must have a high value of the elastic constant K ₃ /K ₁ ratio, a high value of the optical anisotropy Δn and a dielectric anisotropy value of Δε≤ -0.5 to be suitable for high-information display elements based on the ECB effect . Electro-optical display elements based on the ECB effect have a homeotropic edge alignment (VA technology = vertical alignment ). Negative dielectric liquid crystal media can also be used in displays using the so-called IPS or FFS effect.

In addition to IPS ( In-Plane Switching ) displays (eg: Yeo, SD, Paper 15.3: "An LC Display for the TV Application", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp. 758 & 759) and In addition to the long-known TN ( twisted nematic ) displays, displays using the ECB effect, as for example in MVA ( Multi-domain Vertical Alignment , e.g.: Yoshide, H. et al., Paper 3.1: "MVA LCD for Notebook or Mobile PCs . ..", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book I, pp. 6-9, and Liu, CT et al., Paper 15.1: "A 46-inch TFT-LCD HDTV Technology ...", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pages 750 to 753), PVA ( patterned vertical alignment , e.g.: Kim, Sang Soo, paper 15.4: "Super PVA Sets New State-of-the-Art for LCD-TV", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp. 760 to 763), ASV ( Advanced Super Viewing Angle , eg: Shigeta, Mitzuhiro and Fukuoka, Hirofumi, Paper 15.2: "Development of High Quality LCDTV", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp. 754-757) mode, the so-called VAN ( Vertically Aligned Nematic ) display has established itself as the most important of the three newer types today One of the LCD monitors, especially for TV applications. The technology is compared in general form, for example, in Souk, Jun, SID Seminar 2004, seminar M-6: "Recent Advances in LCD Technology", Seminar Lecture Notes, M-6/1 to M-6/26, and Miller , Ian, SID Seminar 2004, seminar M-7: "LCD-Television", Seminar Lecture Notes, M-7/1 to M-7/32. Although the response time of modern ECB displays has been significantly improved by the addressing method under overdrive, for example: Kim, Hyeon Kyeong et al., Paper 9.1: "A 57-in. Wide UXGA TFT-LCD for HDTV Application", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book I, pp. 106-109, but obtaining video-compatible response times, especially in the case of grayscale switching, remains an unsatisfactory problem.

The industrial application of this effect in electro-optic display elements requires an LC phase, which must meet various requirements. Of particular importance here is the chemical resistance to moisture, air and physical influences such as heat, infrared, visible and UV radiation as well as direct and alternating electric fields.

Furthermore, an industrially usable LC phase needs to have a liquid crystal mesophase at a suitable temperature range and low viscosity.

None of the hitherto disclosed series of compounds having a liquid crystalline mesophase includes a single compound that meets all of these requirements. Thus, mixtures of 2-25, preferably 3-18 compounds are usually prepared to obtain a material that can be used as an LC phase. However, it has not yet been possible to easily prepare optimal phases in this way, since there are currently no liquid crystal materials with a pronounced negative dielectric anisotropy and suitable long-term stability available.

Matrix liquid crystal displays (MLC displays) are known. Non-linear elements that can be used for single-picture-unit-single switching are, for example, active elements (ie, transistors). The term "active matrix" is then used, where a distinction can be made between the following two types: 1. MOS (Metal Oxide Semiconductor) transistors on a silicon wafer (as a substrate) 2. Thin-film transistors (TFTs) on a glass plate (as a substrate). In the case of type 1, the electro-optic effect used is usually dynamic scattering or guest-host effect. The use of monocrystalline silicon as the substrate material limits the size of the display, since smooth modular assembly of multiple part displays presents problems at the joints.

In the case of the more promising type 2, which is preferred, the electro-optic effect used is usually the TN effect.

A distinction is made between the two technologies: TFTs containing compound semiconductors, for example, CdSe, or TFTs based on polycrystalline or amorphous silicon. The latter technology is being intensively developed globally.

The TFT matrix is applied to the inside of one glass plate of the display, while the other glass plate carries a transparent counter electrode on its inside. Compared with the size of the pixel electrode, the TFT is very small and has no substantial adverse effect on the image. The technique can also be extended to fully colour-capable displays, where the tessellation of red, green and blue filters is arranged in such a way that the filter elements are relative to each switchable primitive.

The term "MLC display" here covers any matrix display with integrated nonlinear elements, i.e. besides the active matrix, there are also displays with passive elements, such as varistors or diodes (MIM = metal-insulator- Metal).

This type of MLC display is particularly suitable for TV applications such as pocket TVs or for high-information displays in automotive or aircraft construction. In addition to the problems regarding the angular dependence of the contrast ratio and the response time, there are also problems with MLC displays due to the insufficiently high specific resistance of the liquid crystal mixture [TOGASHI, S., SEKIGUCHI, K., TANABE, H., YAMAMOTO, E. , SORIMACHI, K., TAJIMA, E., WATANABE, H., SHIMIZU, H., Proc. Eurodisplay 84, September, 1984: A 210-288 Matrix LCD Controlled by Double Stage Diode Rings, p. 141, Paris; STROMER, M., Proc. Eurodisplay 84, September, 1984: Design of Thin Film Transistors for Matrix Addressing of Television Liquid Crystal Displays, p. 145, Paris]. As the resistance is lowered, the contrast ratio of MLC displays gets worse. The specific resistance of the liquid crystal mixture usually decreases over the lifetime of the MLC display due to the interaction of the inner surfaces of the display, thus a high (initial) resistance is very important for a display which must have an acceptable resistance value after long-term operation.

There is thus a continuing great need for MLC displays with very high specific resistance while having a wide operating temperature range, short response time and low threshold voltage, with the aid of which a variety of gray scales can be produced.

Disadvantages of frequently used MLC-TN displays are their relatively low contrast ratio, relatively high viewing angle dependence and difficulty in producing gray scales in these displays.

VA displays have significantly better viewing angle dependence and are therefore mainly used in televisions and monitors. However, there is still a need to improve the response time here, especially for TV applications with frame rates (picture change frequency/repetition rate) greater than 60 Hz. At the same time, however, properties such as low-temperature stability must not be affected.

Another problem is that existing LC media with negative dielectric anisotropy for FFS-mode displays like UB-FFS often do not show high enough reliability, especially when used in high-end products such as 8K TVs , which can cause, for example, short-term image stickiness or black dot mura.

In particular, in active-matrix LC displays (AMLCDs), a type of areal image sticking known as white-black image sticking (WB I/S) has been observed. In this type of sticking, after a white/black pattern is displayed, a difference in brightness between the driven and non-driven areas of the display can be seen, so that even after a certain relaxation time, the driven areas still look brighter than the Non-driven areas are brighter or darker. Various causes of this sticky image have been identified in the meantime, however, the phenomenon is still frequently observed.

It is an object of the present invention to provide LC media, especially for monitor and TV applications, which are based on ECB, IPS or FFS effects, which do not have or only to a reduced extent the above-mentioned disadvantages. In particular, it should be ensured that LC media for monitors and televisions also operate at very high and low temperatures, and at the same time have short response times and improved reliability, and show reduced image sticking, especially It is reduced black and white image stickiness, and reduced black dot display unevenness.

Said object is achieved by providing LC media as described and claimed hereinafter, in which small amounts of one or more compounds of the formula C with positive dielectric anisotropy are added to an LC mixture with negative dielectric anisotropy. It has surprisingly been found that the LC media according to the invention exhibit high reliability, reduced image sticking and black spot unevenness compared to LC media containing no compounds of the formula C or having higher amounts of these compounds, While maintaining other desirable properties such as short response time, high light transmittance, and low threshold voltage.

The use of LC mixtures with negative dielectric anisotropy as disclosed and claimed hereinafter surprisingly leads to very low rotational viscosities and a reduction in the ratio of rotational viscosity to elastic constants, while maintaining high reliability and high VHR values, and at the same time showed reduced image stickiness, especially reduced white and black image stickiness. It is thus possible to prepare liquid crystal mixtures, preferably VA, PS (=polymer stabilized)-VA, SA (=self-aligned)-VA, IPS, PS-IPS, PS-FFS, FFS mixtures, especially UB-FFS (ultra bright fringe field switching) or PS-UB-FFS hybrids, which have short response times and good reliability, and at the same time have good phase properties and good low-temperature behavior.

The invention relates to liquid crystal (LC) media having negative dielectric anisotropy and comprising one or more compounds of the formula C: C wherein the individual groups are independent of each other and have the same or different meanings at each occurrence: ^R is a linear, branched or cyclic alkyl group having 1 to 25 C atoms, one or more of which are not adjacent The CH ₂ -group is optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, CR ⁰ =CR ⁰⁰ -, - C≡C-, , , , , or Substituted in such a way that the O- and/or S-atoms are not directly connected to each other, and wherein one or more H atoms are each optionally replaced by F or Cl, preferably an alkyl or alkoxy group having 1 to 6 C atoms group, L ¹ and L ² are F, Cl, OCF ₃ , CF ₃ , CH ₃ , CH ₂ F or CHF ₂ , preferably F or Cl, very preferably F.

The invention further relates to the use of LC media as described above and below for electro-optic purposes, in particular for VA, PS-VA, SA-VA, IPS, PS-IPS, FFS, PS-FFS, UB-FFS or Use of PS-UB-FFS displays or shutter glasses or 3D applications.

The invention further relates to an electro-optic LC display comprising an LC medium as described above and below, in particular VA, PS-VA, SA-VA, IPS, PS-IPS, FFS, PS-FFS, UB-FFS or PS-UB -FFS display.

The present invention further relates to a process for the preparation of LC media as described above and below, comprising the step of mixing one or more compounds selected from formula C with other LC compounds and optionally with one or more additives.

If in the formulas shown above and below, the groups R ^1-13 , R ⁵¹ , R ⁵² , R ^Q , R, R ^2A , R ^2B , R ^IIIA , R ^1N , R ^2N , R ^B1 , R ^B2 , R ^CR1 , R ^CR2 , R or L represent an alkyl and/or alkoxy group, which may refer to a straight chain or a branched chain. It is preferably straight-chain, has 2, 3, 4, 5, 6 or 7 C atoms and thus preferably represents ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy Butoxy, pentyloxy, hexyloxy or heptyloxy, also methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl , pentadecyl, methoxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy or tetradecyloxy.

If in the formulas shown above and below, the groups R ^1-13 , R ⁵¹ , R ⁵² , R ^Q , R, R ^2A , R ^2B , R ^IIIA , R ^1N , R ^2N , R ^B1 , R ^B2 , R ^CR1 , R ^CR2 , R or L represent an alkyl group in which one or more CH ₂ groups are replaced by S, then it may be linear or branched. It is preferably linear, with 1, 2, 3, 4, 5, 6 or 7 C atoms, and thus preferably represents thiomethyl, thioethyl, thiopropyl, thiobutyl, thiopentyl, thio Hexyl or Thioheptyl.

Oxaalkyl preferably denotes straight-chain 2-oxapropyl (=methoxymethyl), 2-oxabutyl (=ethoxymethyl) or 3-oxabutyl (=2-methoxymethyl) oxyethyl), 2-oxa-pentyl, 3-oxa-pentyl or 4-oxa-pentyl, 2-oxa-hexyl, 3-oxa-hexyl, 4-oxa-hexyl or 5-oxa-hexyl , 2-oxaheptyl, 3-oxaheptyl, 4-oxaheptyl, 5-oxaheptyl or 6-oxaheptyl, 2-oxaoctyl, 3-oxaoctyl, 4-oxa-octyl, 5-oxa-octyl, 6-oxa-octyl or 7-oxa-octyl, 2-oxa-nonyl, 3-oxa-nonyl, 4-oxa-nonyl, 5 -oxanonyl, 6-oxanonyl, 7-oxanonyl or 8-oxanonyl, 2-oxadecyl, 3-oxadecyl, 4-oxadecyl, 5- Oxadecyl, 6-oxadecyl, 7-oxadecyl, 8-oxadecyl or 9-oxadecyl.

If in the formulas shown above and below, the groups R ^1-13 , R ⁵¹ , R ⁵² , R ^Q , R, R ^2A , R ^2B , R ^IIIA , R ^1N , R ^2N , R ^B1 , R ^B2 , R ^CR1 , R ^CR2 , R or L represent alkoxy or oxaalkyl, which may also contain one or more additional oxygen atoms, provided that the oxygen atoms are not directly connected to each other.

In another preferred embodiment, R ^1-13 , R ⁵¹ , R ⁵² , R ^Q , R, R ^2A , R ^2B , R ^IIIA , R ^1N , R ^2N , R ^B1 , R ^B2 , R ^CR1 , R One or more of ^CR2 , R or L selected from , , , , , , , , , , , , -S ¹ -F, -OS ¹ -F, -OS ₁ -OS ₂ , wherein S ¹ is C _1-12 -alkylene or C _2-12 -alkylene and S ² is H , C _1-12 -alkyl or C _2-12 -alkenyl, and very preferably selected from , , , , , , , , , , , , , , , , , , , -OCH ₂ OCH ₃ , -O(CH ₂ ) ₂ OCH ₃ , -O(CH ₂ ) ₃ OCH ₃ , -O(CH ₂ ) ₄ OCH ₃ , -O(CH ₂ ) ₂ F, -O(CH ₂ ) A group consisting of ₃ F, -O(CH ₂ ) ₄ F.

If in the formulas shown above and below, the groups R ^1-13 , R ⁵¹ , R ⁵² , R ^Q , R, R ^2A , R ^2B , R ^IIIA , R ^1N , R ^2N , R ^B1 , R ^B2 , R ^CR1 , R ^CR2 , R or L represent an alkyl group in which one CH ₂ group has been replaced by -CH=CH-, which may be linear or branched. It is preferably linear and has 2 to 10 C atoms. It thus denotes, in particular vinyl, prop-1-enyl or prop-2-enyl, but-1-enyl, but-2-enyl or but-3-enyl, pent-1-enyl pent-2-enyl, pent-3-enyl or pent-4-enyl, hex-1-enyl, hex-2-enyl, hex-3-enyl, hex-4-enyl Or hex-5-enyl, hep-1-enyl, hep-2-enyl, hep-3-enyl, hep-4-enyl, hep-5-enyl, hep-6-enyl, Oct-1-enyl, Oct-2-enyl, Oct-3-enyl, Oct-4-enyl, Oct-5-enyl, Oct-6-enyl or Oct-7-enyl, Nonyl -1-enyl, non-2-enyl, non-3-enyl, non-4-enyl, non-5-enyl, non-6-enyl, non-7-enyl or non- 8-enyl, dec-1-enyl, dec-2-enyl, dec-3-enyl, dec-4-enyl, dec-5-enyl, dec-6-enyl, dec-7 -enyl, dec-8-enyl or dec-9-enyl.

If in the formulas shown above and below, the groups R ^1-13 , R ⁵¹ , R ⁵² , R ^Q , R, R ^2A , R ^2B , R ^IIIA , R ^1N , R ^2N , R ^B1 , R ^B2 , R ^CR1 , R ^CR2 , R or L represent an alkyl or alkenyl at least monosubstituted by halogen, the group is preferably linear, and the halogen is preferably F or Cl. In the case of polysubstitution, halogen is preferably F. The resulting groups also include perfluoro groups. In the case of monosubstitution, the fluorine or chlorine substituents can be in any desired position, but are preferably in the ω position.

Halogen is preferably F or Cl, very preferably F.

The radical -CR ⁰ =CR ⁰⁰ - is preferably -CH=CH-.

-CO-, -C(=O)- and -C(O)-represent carbonyl, ie .

Preferred substituents L are for example F, Cl, Br, I, -CN, -NO ₂ , -NCO, -NCS, -OCN, -SCN, -C(=O)N(R ^x ) ₂ , -C( =O)Y ¹ , -C(=O)R ^x , -N(R ^x ) ₂ , linear or branched alkyl, alkoxy, alkylcarbonyl, alkoxy each having 1 to 25 carbon atoms ylcarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, wherein one or more H atoms may optionally be replaced by F or Cl, optionally substituted silyl groups (silyl) with 1 to 20 Si atoms , or an optionally substituted aryl group having 6 to 25, preferably 6 to 15, carbon atoms, wherein R ^x represents H, F, Cl, CN or a straight chain, branched chain or ring having 1 to 25 C atoms like alkyl, wherein one or more non-adjacent _CH2- groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO -O- is replaced in such a way that O- and/or S-atoms are not directly connected to each other, and wherein one or more H atoms are each optionally replaced by F, Cl, P- or P-Sp-, and ^Y represents halogen.

Particularly preferred substituents L are, for example, F, Cl, CN, NO ₂ , CH ₃ , C ₂ H ₅ , OCH ₃ , OC ₂ H ₅ , COCH ₃ , COC ₂ H ₅ , COOCH ₃ , COOC ₂ H ₅ , CF _3. OCF ₃ , OCHF ₂ , OC ₂ F ₅ , and phenyl. preferably or wherein L has one of the above meanings.

The LC media according to the invention preferably exhibit a very broad nematic range with a clearing point of ≧70° C., preferably ≧74° C., very favorable values for the capacitance threshold, relatively high retention values and at the same time very good Low temperature stability at -20°C and -30°C, as well as very low rotational viscosity and short response time.

Furthermore, the LC media according to the invention are characterized in that, in addition to an improved rotational viscosity γ ₁ , high reliability and high VHR values even after UV exposure can be achieved.

Furthermore, the LC media according to the invention are characterized in that, in addition to the improvement of the rotational viscosity γ ₁ , a relatively high value of the elastic constant value K ₃ for improving the response time is also observed. In particular, the mixtures according to the invention have a particularly low ratio γ ₁ /K ₃ of the rotational viscosity γ ₁ to the value of the elastic constant K ₃ , which exhibits a fast response time.

Furthermore, the LC media according to the invention do surprisingly show high reliability and high VHR values after UV exposure, while showing reduced image sticking, especially reduced white and black image sticking, even with In case only a small amount of the compound of formula C is included.

In compounds of formula C and its sub-formulas, R ^preferably represents an alkyl or alkoxy group having 1 to 9, preferably 1 to 6, C atoms, all of which are optionally fluorinated, or having 3, A cycloalkyl ring of 4 or 5 carbon atoms, very preferably ethyl, n-propyl or n-butyl, most preferably ethyl.

Preferred compounds of formula C are selected from the following formulae: C1 wherein ^R has one of the meanings of formula C or one of the preferred meanings given above and below, and is preferably ethyl, n-propyl or n-butyl, most preferably ethyl. Preferably, the proportion of compounds of the formula C or C1 in the LC medium is >0 to ≤15% by weight, more preferably >0 to ≤7% by weight, even more preferably >0 to ≤5% by weight, very preferably 0.2 to 4% by weight, Most preferred is 0.5 to 4% by weight.

Preferably, the LC medium contains 1, 2 or 3, most preferably 1 compound of formula C or C1.

In a preferred embodiment, the LC medium comprises one or more compounds of formula II: II wherein each group is independent of each other and has the same or different ^meanings at each occurrence: R and ^R are linear, branched or cyclic alkyl groups having 1 to 25 C atoms, one or more of which Nonadjacent _CH2 -groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, CR ⁰ =CR ⁰⁰ -, -C≡C-, , , , , or Substituted in such a way that the O- and/or S-atoms are not directly connected to each other, and wherein one or more H atoms are each optionally replaced by F or Cl, preferably an alkyl or alkoxy group having 1 to 6 C atoms group, ^A1 and ^A2 are groups selected from the following formulas: A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13 A14 A15 A16 Preferably selected from formulas A1, A2, A3, A4, A5, A6, A9 and A10, very preferably selected from formulas A1, A2, A3, A4, A5, A9 and A10, ^Z and ^Z are _-CH CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -CO-O-, -O-CO-, -C ₂ F ₄ -, -CF=CF-, -CH=CH-CH ₂ O- or a single bond, preferably a single bond, L ¹ , L ² , L ³ and L ⁴ are F, Cl, OCF ₃ , CF ₃ , CH ₃ , CH ₂ F or CHF ₂ , preferably F or Cl, very preferably F, Y is H, F, Cl, CF ₃ , CHF ₂ or CH ₃ , preferably H or CH ₃ , very preferably H, ^LC is CH ₃ or OCH ₃ , preferably CH ₃ , a1 is 1 or 2, and a2 is 0 or 1.

Preferably, the LC medium comprises one or more compounds of formula II selected from compounds of formula IIA, IIB, IIC and IID: IIA IIB IIC IID wherein each of R ^2A and R ^2B independently of each other represents H, an alkyl or alkenyl group having up to 15 C atoms, which is unsubstituted, monosubstituted by CN or CF ₃ or at least monosubstituted by halogen, wherein in addition, these One or more _CH2 groups in the group can be replaced by -O-, -S-, , , , , , -C≡C-, -CF ₂ O-, -OCF ₂ -, -OC-O-, or -O-CO- are substituted in such a way that the O atoms are not directly connected to each other, L ¹ to L ⁴ are each independently of each other represents F, Cl, CF ₃ or CHF ₂ , Y represents H, F, Cl, CF ₃ , CHF ₂ or CH ₃ , preferably H or CH ₃ , particularly preferably H, Z ² , Z ^2B and Z ^2D are each independently of each other Indicates single bond, -CH ₂ CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO-, -C ₂ F ₄ -, -CF=CF-, -CH= _CHCH2O- , p represents 0, 1 or 2, and q represents 0 or 1 identically or differently at each occurrence.

Preferred compounds of formulas IIA, IIB, IIC and IID are those in which R ^2B represents an alkyl or alkoxy group having up to 15 C atoms, and very preferably represents (O)C _v H _2v+1 , wherein (O ) is an oxygen atom or a single bond and v is 1, 2, 3, 4, 5 or 6.

Further preferred compounds of formulas IIA, IIB, IIC and IID are wherein R ^2A or R ^2B represent or contain cycloalkyl or cycloalkoxy, preferably selected from , , , , , , , , , , , , wherein S ¹ is C _1-5 -alkylene or C _2-5 -alkenyl and S ² is H, C _1-7 -alkyl or C _2-7 -alkenyl, and is very preferably selected from , , , , , , , , , , , , , , , , , , of those compounds.

Further preferred compounds of formula IIA, IIB, IIC and IID are shown below: IIA-1 IIA-2 IIA-3 IIA-4 IIA-5 IIA-6 IIA-7 IIA-8 IIA-9 IIA-10 IIA-11 IIA-12 IIA-13 IIA-14 IIA-15 IIA-16 IIA-17 IIA-18 IIA-19 IIA-20 IIA-21 IIA-22 IIA-23 IIA-24 IIA-25 IIA-26 IIA-27 IIA-28 IIA-29 IIA-30 IIA-31 IIA-32 IIA-33 IIA-34 IIA-35 IIA-36 IIA-37 IIA-38 IIA-39 IIA-40 IIA-41 IIA-42 IIA-43 IIA-44 IIA-45 IIA-46 IIB-1 IIB-2 IIB-3 IIB-4 IIB-5 IIB-6 IIB-7 IIB-8 IIB-9 IIB-10 IIB-11 IIB-12 IIB-13 IIB-14 IIB-15 IIB-16 IIB-17 IIB-18 IIB-19 IIB-20 IIB-21 IIB-22 IIB-23 IIB-24 IIC-1 IID-1 IID-2 IID-3 IID-4 IID-5 IID-6 IID-7 wherein the parameter a represents 1 or 2, alkyl and alkyl ^* independently of each other represent a straight-chain alkyl group having 1-6 C atoms, and alkenyl represents a straight-chain alkenyl group having 2-6 C atoms, and (O) represents Oxygen atom or single bond. alkenyl preferably denotes CH ₂ =CH-, CH ₂ =CHCH ₂ CH ₂ -, CH ₃ -CH=CH-, CH ₃ -CH ₂ -CH=CH-, CH ₃ -(CH ₂ ) ₂ -CH=CH- , CH ₃ -(CH ₂ ) ₃ -CH=CH- or CH ₃ -CH=CH-(CH ₂ ) ₂ -.

In a preferred embodiment, the LC medium comprises one or more compounds selected from the group consisting of formulas IIA and IIB and subformulae thereof.

In another preferred embodiment, the LC medium comprises one or more compounds of formula IIC or a subformula thereof.

In another preferred embodiment, the LC medium comprises one or more compounds of formula IID or a subformula thereof.

Particularly preferred LC media according to the invention comprise one or more compounds selected from the group consisting of formulas 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, most preferably selected from compounds of formula IIA-2, IIA-10, IIB-10, IIC-1 and IID-4.

The proportion of compounds of the formulas IIA and/or IIB in the overall mixture is preferably at least 20% by weight.

The proportion of the compound of formula IIC in the entire mixture is preferably 0.5 to 10% by weight, more preferably 0.5 to 5% by weight, most preferably 1 to 3% by weight.

The proportion of the compound of formula IID in the total mixture is preferably 2 to 40% by weight, more preferably 5 to 25% by weight.

In another preferred embodiment, the LC medium comprises one or more compounds of formula III: III wherein R ¹¹ and R ¹² each independently represent H, an alkyl or alkoxy group having 1 to 15 C atoms, wherein one or more _CH groups in these groups may each independently be represented by , , , , , -C≡C-, -CF ₂ O-, -OCF ₂ -, -CH=CH-, replaced by -O-, -CO-O- or -O-CO- so that the O atoms are not directly connected to each other , and wherein in addition, one or more H atoms may be replaced by halogen, A ³ independently of each other at each occurrence represents a) 1,4-cyclohexenyl or 1,4-cyclohexylene, where one or _two non-adjacent CH groups may be replaced by -O- or -S-, b) 1,4-phenylene groups where one or both CH groups may be replaced by N, or c) Selected from spiro[3.3]heptane-2,6-diyl, 1,4-bicyclo[2.2.2]octyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-Tetralin-2,6-diyl, phenanthrene-2,7-diyl and fluorene-2,7-diyl radicals, wherein the radicals a), b) and c ) can be mono- or polysubstituted by halogen atoms, n represents 0, 1 or 2, preferably 0 or 1, Z ¹ independently of each other at each occurrence represents -CO-O-, -O-CO-, -CF ₂ O -, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -CH ₂ -, -CH ₂ CH ₂ -, -(CH ₂ ) ₄ -, -CH=CH-CH ₂ O-, -C ₂ F ₄ -, -CH ₂ CF ₂ -, -CF ₂ CH ₂ -, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C- or bond, and L ¹¹ and L ¹² each independently of each other represent F, Cl, CF ₃ or CHF ₂ , preferably H or F, most preferably F, and W represents O or S.

In a preferred embodiment of the invention, the LC medium comprises one or more compounds of formula III-1 and/or III-2: III-1 III-2 The groups occurring therein ^have the same meanings as given above under formula III, and preferably R and ^R are each independently of each other an alkyl, alkenyl or alkoxy group having up to 15 C atoms, more preferably , one or two of them represent an alkoxy group, and each of L ¹¹ and L ¹² represents F. In formulas III, III-1 and III-2, preferably R and ^R represent linear alkoxy groups with 1-6 C atoms, very ^preferably ethoxy, propoxy, butoxy, pentyloxy base or hexyloxy. R ¹ very preferably represents ethoxy or propoxy, most preferably propoxy. ^R2 very preferably represents ethoxy, propoxy, butoxy, pentyloxy or hexyloxy, most preferably butoxy, pentyloxy or hexyloxy.

In a preferred embodiment, the LC medium comprises one or more compounds of formula III-1 selected from formulas III-1-1 to III-1-10, preferably formula III-1-6: III-1-1 III-1-2 III-1-3 III-1-4 III-1-5 III-1-6 III-1-7 III-1-8 III-1-9 III-1-10, Wherein "alkyl" and "alkyl ^* " each independently represent a straight-chain alkyl group having 1-6 C atoms, and "alkenyl" and "alkenyl ^* " each independently represent a straight-chain group having 2-6 C atoms Alkenyl, "alkoxy" and "alkoxy ^* " each independently represent a straight-chain alkoxy group having 1 to 6 C atoms, and ^L11 and ^L12 each independently represent F or Cl, preferably both represent F.

In another preferred embodiment, the LC medium comprises one or more compounds of formula III-2 or a subformula thereof.

Very preferably, the LC medium comprises one or more compounds of formula III-2 selected from formulas III-2-1 to III-2-10, preferably formula III-2-6: III-2-1 III-2-2 III-2-3 III-2-4 III-2-5 III-2-6 III-2-7 III-2-8 III-2-9 III-2-10, Wherein "alkyl" and "alkyl ^* " each independently represent a straight-chain alkyl group having 1-6 C atoms, and "alkenyl" and "alkenyl ^* " each independently represent a straight-chain group having 2-6 C atoms Alkenyl, "alkoxy" and "alkoxy ^* " each independently represent a straight-chain alkoxy group having 1 to 6 C atoms, and ^L11 and ^L12 each independently represent F or Cl, preferably both represent F.

In a very preferred embodiment, the LC medium comprises one or more compounds selected from the formula: III-2-6-1 III-2-6-2 III-2-6-3.

In another preferred embodiment of the invention, the LC medium comprises one or more compounds of formula IIIA-1 and/or IIIA-2: IIIA-1 IIIA-2 wherein L ¹¹ and L ¹² have the same meanings as given under formula III, (O) represents O or a single bond, R ^IIIA represents an alkyl or alkenyl group or group Cy-C _m H having up to 7 C atoms _2m+1- , L ¹¹ and L ¹² each independently represent F, Cl, CF ₃ or CHF ₂ , preferably H or F, most preferably F, and m and n are identically or differently 0, 1, 2, 3 , 4, 5 or 6, preferably 1, 2 or 3, very preferably 1, and Cy represents a cycloaliphatic group with 3, 4 or 5 ring atoms, which is optionally divided by each having up to 3 C Atoms are alkyl or alkenyl substituted or substituted by halogen or CN, and preferably represent cyclopropyl, cyclobutyl or cyclopentyl.

Instead of or in addition to, preferably in addition to, compounds of formula III, the LC medium also contains compounds of formulas IIIA-1 and/or IIIA-2.

Very preferred compounds of formula IIIA-1 and IIIA-2 are as follows: IIIA-1-1 IIIA-1-2 IIIA-1-3 IIIA-2-1 IIIA-2-2 IIIA-2-3 wherein alkoxy represents a straight-chain alkoxy group having 1-6 C atoms.

Particularly preferred compounds of formula IIIA-2 are as follows: IIIA-2-3-1 IIIA-2-3-2 IIIA-2-3-3

In a preferred embodiment of the invention, the LC medium comprises one or more compounds of formula III-3: III-3 wherein R ¹¹ , R ¹² identically or differently represent H, an alkyl or alkoxy group having 1 to 15 C atoms, wherein one or more CH ₂ groups in these groups are optionally independently of each other by - C≡C-, -CF ₂ O-, -OCF ₂ -, -CH=CH-, -O-, -CO-O- or -O-CO- are substituted in such a way that the O atoms are not directly bonded to each other, and wherein, in addition, one or more H atoms may be substituted by halogen.

Compounds of formula III-3 are preferably selected from compounds of formulas III-3-1 to III-3-10: III-3-1 III-3-2 III-3-3 III-3-4 III-3-5 III-3-6 III-3-7 III-3-8 III-3-9 III-3-10 wherein R ¹² represents an alkyl group having 1 to 7 C atoms, preferably ethyl, n-propyl or n-butyl, or alternatively cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl.

In another preferred embodiment of the invention, the LC medium comprises one or more compounds of formula III-4 to III-6, preferably of formula III-5: III-4 III-5 III-6 Where the parameters have the meanings given above, R ¹¹ preferably represents straight-chain alkyl and R ¹² preferably represents alkoxy, each having 1 to 7 C atoms.

In another preferred embodiment, the LC medium comprises one or more compounds of formula III selected from formulas III-7 to III-9, preferably formula III-8: III-7 III-8 III-9 Where the parameters have the meanings given above, R ¹¹ preferably represents straight-chain alkyl and R ¹² preferably represents alkoxy, each having 1 to 7 C atoms.

Preferably, the LC medium comprises one or more compounds selected from formulas III-1 and III-2.

Preferably, the LC medium contains 1, 2 or 3 compounds of formula III or a subformula thereof.

Preferably, the LC medium comprises one or more compounds of formula III-2.

Preferably, the total proportion of compounds of the formula III and subformulae thereof in the LC medium is 2 to 20% by weight, very preferably 5 to 15% by weight.

In a preferred embodiment, the medium comprises one or more compounds of formula IV: IV wherein ^R represents unsubstituted alkyl having 1 to 7 C atoms or unsubstituted alkenyl having 2 to 7 C atoms, preferably n-alkyl, particularly preferably having 2, 3, 4 or 5 C atoms , and R ^represents unsubstituted alkyl having 1 to 7 C atoms or unsubstituted alkoxy having 1 to 6 C atoms, both preferably having 2 to 5 C atoms, having 2 to 7 C atom, preferably unsubstituted alkenyl having 2, 3 or 4 C atoms, more preferably vinyl or 1-propenyl, and especially vinyl.

Compounds of formula IV are preferably selected from compounds of formulas IV-1 to IV-4: IV-1 IV-2 IV-3 IV-4 wherein alkyl and alkyl' independently of each other represent an alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms, alkenyl represents 2 to 5 C atoms, preferably 2 to 4 C atoms, particularly preferably An alkenyl group having 2 C atoms, alkenyl' denotes an alkenyl group having 2 to 5 C atoms, preferably 2 to 4 C atoms, particularly preferably 2 to 3 C atoms, and alkoxy denotes an alkenyl group having 1 to 5 C atoms C atoms, preferably alkoxy groups having 2 to 4 C atoms.

Preferably, the LC medium comprises one or more compounds selected from formulas IV-1-1 to IV-1-6: IV-1-1 IV-1-2 IV-1-3 IV-1-4 IV-1-5 IV-1-6

In a preferred embodiment, the LC medium according to the invention comprises one or more compounds of formula IV-2-1 and/or IV-2-2: IV-2-1 IV-2-2

In another preferred embodiment, the LC medium according to the invention comprises a compound of the formula IV-3, in particular a compound selected from the formulas IV-3-1 to IV-3-4 IV-3-1 IV-3-2 IV-3-3 IV-3-4 Very preferably, the LC medium according to the invention comprises a compound of formula IV-3-1 and/or a compound of formula IV-3-3.

In another preferred embodiment, the LC medium according to the invention comprises a compound of the formula IV-4, in particular a compound selected from the formulas IV-4-1 and IV-4-2: IV-4-1 IV-4-2

The LC medium preferably additionally comprises one or more compounds of formula IVa: IVa wherein each ^of R and ^R independently of each other represents a straight-chain alkyl, alkoxy, alkenyl, alkoxyalkyl or alkoxy having up to 12 C atoms, and express , , , or , Z ⁴ represents a single bond, -CH ₂ CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO-, -C ₂ F ₄ -, -C ₄ H ₈ - or -CF=CF-.

Preferred compounds of formula IVa are shown below: IVa-1 IVa-2 IVa-3 IVa-4 wherein alkyl and alkyl ^* each independently represent a linear alkyl group having 1 to 6 C atoms.

The LC medium according to the invention preferably comprises at least one compound of the formula IVa-1 and/or the formula IVa-2.

The proportion of the compound of the formula IVa in the overall mixture is preferably at least 5% by weight.

Preferably, the LC medium comprises one or more compounds of formula IVb-1 to IVb-3: IVb-1 IVb-2 IVb-3 wherein alkyl and alkyl ^* each independently represent a straight-chain alkyl group having 1 to 6 C atoms, and alkenyl and alkenyl ^* each independently represent a straight-chain alkenyl group having 2 to 6 C atoms.

The proportion of biphenyls of the formulas IV-1 to IV-3 in the overall mixture is preferably at least 3% by weight, in particular ≧5% by weight.

Among the compounds of the formulas IVb-1 to IVb-3, the compounds of the formula IVb-2 are particularly preferred.

Particularly preferred biphenyls are as follows: IVb-1-1 IVb-2-1 IVb-2-2 IVb-2-3 wherein alkyl ^* denotes an alkyl group having 1 to 6 C atoms and preferably denotes n-propyl.

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

In a preferred embodiment, the LC medium comprises one or more compounds of formula V: V wherein R ⁵¹ and R ⁵² independently of one another have one of the meanings given for R ⁴¹ and R ⁴² and preferably represent an alkyl group having 1 to 7 C atoms, preferably an n-alkyl group, particularly preferably having 1 to 5 C atoms n-alkyl, alkoxy having 1 to 7 C atoms, preferably n-alkoxy, particularly preferably n-alkoxy having 2 to 5 carbon atoms, having 2 to 7 carbon atoms, preferably 2 to Alkoxyalkyl, alkenyl or alkenyloxy with 4 carbon atoms, preferably alkenyloxy, , express the same or differently , , , , , or in preferred representation or , Z ⁵¹ and Z ⁵² each independently represent -CH ₂ -CH ₂ -, -CH ₂ -O-, -CH=CH-, -C≡C-, -COO- or a single bond, preferably -CH ₂ -CH ₂ -, -CH ₂ -O- or a single bond, and particularly preferably a single bond, and n is 1 or 2.

Compounds of formula V are preferably selected from compounds of formulas V-1 to V-16: V-1 V-2 V-3 V-4 V-5 V-6 V-7 V-8 V-9 V-10 V-11 V-12 V-13 V-14 V-15 V-16 wherein R ¹ and R ² have the meanings indicated above for R ^2A . R ¹ and R ² preferably each independently represent a linear alkyl or alkenyl group.

Preferably, the LC medium comprises one or more of formulas V-1, V-3, V-4, V-6, V-7, V-10, V-11, V-12, V-14, V-15 and /or compounds of V-16

The LC media according to the invention very particularly preferably comprise compounds of the formulas V-10, V-12, V-16 and/or IV-1, in particular present in an amount of 5 to 30%.

Preferred compounds of formula V-10 are shown below: V-10a V-10b V-10c The LC media according to the invention particularly preferably comprise tricyclic compounds of the formula V-10a and/or V-10b in combination with one or more bicyclic compounds of the formula IV-1. The total proportion of the combination of compounds of the formula V-10a and/or V-10b with one or more bicyclohexyl compounds of the formula IV-1 is from 5 to 40%, very particularly preferably from 15 to 35%.

Very particularly preferably, the LC medium comprises compounds of the formula V-10a and/or IV-1-1: V-10a IV-1-1 Compounds V-10a and IV-1-1 are preferably present in the mixture in a concentration of 15 to 35%, particularly preferably 15 to 25%, and especially preferably 18 to 22%, based on the entire mixture.

Further particularly preferably, the LC medium comprises compounds of formula V-10b and/or IV-1-1: V-10b IV-1-1. Compounds V-10b and IV-1-1 are preferably present in the mixture in a concentration of 15 to 35%, particularly preferably 15 to 25%, and especially preferably 18 to 22%, based on the entire mixture.

Very particularly preferred LC media comprise compounds of the following three formulas: V-10a V-10b IV-1-1. Compounds V-10a, V-10b and IV-1-1 are preferably present in the mixture in a concentration of 15 to 35%, particularly preferably 15 to 25%, and especially preferably 18 to 22%, based on the entire mixture.

Preferred LC media comprise at least one compound selected from the group consisting of: V-6 V-7 IV-1 Wherein R ⁴¹ and R ⁴² , and R ⁵¹ and R ⁵² have the above meanings. Preferably, in compounds V-6, V-7 and IV-1, R ⁴¹ and R ⁵¹ respectively represent an alkyl or alkenyl group having 1 to 6 or 2 to 6 C atoms, and R ⁴² and R ⁵² denotes an alkenyl group having 2 to 6 C atoms.

Preferably, the LC medium comprises at least one compound selected from the group consisting of formulas V-6a, V-6b, V-7a, V-7b, IV-4-1, IV-4-2, IV-3a and IV-3b: V-6a V-6b V-7a V-7b IV-4-1 IV-4-2 IV-3a IV-3b wherein alkyl represents an alkyl group having 1 to 6 C atoms, and alkenyl represents an alkenyl group having 2 to 6 C atoms.

Compounds of formula V-6a, V-6b, V-7a, V-7b, IV-4-1, IV-4-2, IV-3a and IV-3b are preferably present in an amount of 1 to 40% by weight, preferably 5 to 35% by weight % by weight, very particularly preferably an amount of 10 to 30% by weight, is present in the LC medium according to the invention.

In a preferred embodiment of the invention, the LC medium additionally comprises one or more compounds of the formulas VI-1 to VI-9: VI-1 VI-2 VI-3 VI-4 VI-5 VI-6 VI-7 VI-8 VI-9 wherein R ⁷ each independently of each other has one of the meanings indicated for R ^2A in formula IIA, and w and x each independently of each other represent 1 to 6. Particular preference is given to LC media comprising at least one compound of the formula V-9.

In a preferred embodiment of the invention, the LC medium additionally comprises one or more compounds of the formulas VII-1 to VII-25: VII-1 VII-2 VII-3 VII-4 VII-5 VII-6 VII-7 VII-8 VII-9 VII-10 VII-11 VII-12 VII-13 VII-14 VII-15 VII-16 VII-17 VII-18 VII-19 VII-20 VII-21 VII-22 VII-23 VII-24 VII-25 wherein R represents a linear alkyl or alkoxy group having 1 to 6 C atoms, (O) represents -O- or a single bond, X represents F, Cl, OCF ₃ or OCHF ₂ , L ^x represents H or F, m is 0, 1, 2, 3, 4, 5 or 6 and n is 0, 1, 2, 3 or 4.

R preferably denotes methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy.

X preferably denotes F or OCH ₃ , very preferably F.

The LC media according to the invention preferably comprise 2 to 30% by weight, in particular 5 to 20% by weight, of terphenyls of the formulas VII-1 to VII-25.

Particular preference is given to compounds of the formulas VII-1, VII-2, VII-4, VII-20, VII-21 and VII-22, in which X represents F. In these compounds, R preferably denotes alkyl, also alkoxy, each having 1 to 5 C atoms. In compounds of formula VII-20, R preferably represents alkyl or alkenyl, especially alkyl. In compounds of formula VII-21, R preferably represents alkyl. In the compounds of formulas VII-22 to VII-25, X preferably represents F.

The terphenyls of the formulas VII-1 to VII-25 are preferably used in the LC media according to the invention if the Δn value of the mixture will be ≧0.1. Preferred LC media comprise 2 to 20% by weight of one or more terphenyl compounds selected from compounds of formulas VII-1 to VII-25.

Further preferred embodiments according to the invention are listed below: a) LC medium comprising at least one compound of the formulas Z-1 to Z-7: Z-1 Z-2 Z-3 Z-4 Z-5 Z-6 Z-7 wherein R, (O) and alkyl have the meanings indicated above for formula III. b) LC media comprising one or more substances containing tetralinyl or naphthyl units, for example compounds of the formulas N-1 to N-5: N-1 N-2 N-3 N-4 N-5 wherein R ^1N and R ^2N each independently of each other have the meanings indicated for R ^2A , preferably represent straight-chain alkyl, straight-chain alkoxy or straight-chain alkenyl, and ^Z and ^{Z each} independently of each other represent -C ₂ H ₄ -, -CH=CH-, -(CH ₂ ) ₄ -, -(CH ₂ ) ₃ O-, -O(CH ₂ ) ₃ -, -CH=CHCH ₂ CH ₂ -, -CH ₂ CH ₂ CH=CH-, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO-, -C ₂ F ₄ -, -CF=CF-, -CF=CH-, -CH=CF-, -CF ₂ O-, -OCF ₂ -, -CH ₂ - or a single bond. c) LC medium comprising one or more compounds selected from the group consisting of difluorodibenzochroman compounds of formula BC, chroman of formula CR and phenanthrene fluoride of formula PH-1 and PH-2: BC CR PH-1 PH-2 wherein R ^B1 , R ^B2 , R ^CR1 , R ^CR2 , R ¹ , R ² each independently have the meaning of R ^2A . c is 0, 1 or 2. R ¹ and R ² preferably independently of each other represent an alkyl or alkoxy group having 1 to 6 C atoms.

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

Particularly preferred compounds of formula BC and CR are compounds BC-1 to BC-7 and CR-1 to CR-5, BC-1 BC-2 BC-3 BC-4 BC-5 BC-6 BC-7 CR-1 CR-2 CR-3 CR-4 CR-5 wherein alkyl and alkyl ^* each independently represent a straight-chain alkyl group having 1 to 6 C atoms, and alkenyl and alkenyl ^* each independently represent a straight-chain alkenyl group having 2 to 6 C atoms.

Very particular preference is given to comprising one, two or three compounds of the formula BC-2, BF-1 and/or BF-2. d) LC media comprising one or more indane compounds of formula In, In wherein R ¹¹ , R ¹² , R ¹³ each independently represent a linear alkyl, alkoxy, alkoxyalkyl or alkenyl group having 1 to 6 C atoms, R ¹² and R ¹³ additionally represent halogen, preferably F, express i represents 0, 1 or 2.

Preferred compounds of formula In are compounds of formula In-1 to In-16 as shown below: In-1 In-2 In-3 In-4 In-5 In-6 In-7 In-8 In-9 In-10 In-11 In-12 In-13 In-14 In-15 In-16 are particularly preferred compounds of the formulas In-1, In-2, In-3 and In-4.

The compounds of the formula In and the subformulas In-1 to In-16 are preferably used in the LC medium according to the invention in a concentration of ≧5% by weight, in particular 5 to 30% by weight and very particularly preferably 5 to 25% by weight. e) LC media comprising one or more compounds of the formulas L-1 to L-5: L-1 L-2 L-3 L-4 L-5, wherein R and R ¹ each independently have the meanings indicated above for R ^2A in formula IIA, and alkyl represents an alkyl group having 1 to 6 C atoms. Parameter s means 1 or 2.

The compounds of the formulas L-1 to L-5 are preferably used in concentrations of 5 to 50% by weight, in particular 5 to 40% by weight and very particularly preferably 10 to 40% by weight. f) LC medium comprising one or more compounds of formula IIA-Y IIA-Y wherein R ¹¹ and R ¹² have the meanings given above for R ^2A in formula IIA, and L ¹ and L ² represent F or Cl identically or differently.

Preferred compounds of formula IIA-Y are selected from the following subformulas: IIA-Y1 IIA-Y2 IIA-Y3 IIA-Y4 IIA-Y5 IIA-Y6 IIA-Y7 IIA-Y8 IIA-Y9 IIA-Y10 Wherein, Alkyl and Alkyl ^* each independently represent a straight-chain alkyl group having 1-6 C atoms, Alkoxy and Alkoxy ^* independently represent a straight-chain alkoxy group having 1-6 C atoms, Alkenyl and Alkenyl ^* Each independently of each other represents a straight-chain alkenyl group having 2 to 6 C atoms, and O represents an oxygen atom or a single bond. Alkenyl and Alkenyl ^* preferably denote CH ₂ =CH-, CH ₂ =CHCH ₂ CH ₂ -, CH ₃ -CH=CH-, CH ₃ -CH ₂ -CH=CH-, CH ₃ -(CH ₂ ) ₂ -CH =CH-, CH ₃ -(CH ₂ ) ₃ -CH=CH- or CH ₃ -CH=CH-(CH ₂ ) ₂ -.

Particularly preferred compounds of formula IIA-Y are selected from the following subformulas: IIA-Y6a IIA-Y6b where Alkoxy and Alkoxy ^* have the above definitions and preferably represent methoxy, ethoxy, n-propoxy, n-butoxy or n-pentoxy.

Very preferably, the LC medium comprises one or more compounds of formula IIA-Y6a. g) LC medium comprising one or more quaterphenyl compounds selected from the following formulae: Q wherein R ^Q is alkyl, alkoxy, oxaalkyl or alkoxyalkyl having 1 to 9 C atoms or alkenyl or alkenyloxy having 2 to 9 C atoms, all of which are optionally is fluorinated, X ^Q is F, Cl, haloalkyl or alkoxy having 1 to 6 C atoms or haloalkenyl or alkenyl oxy having 2 to 6 C atoms, L ^Q1 to L ^Q6 are each other are independently H or F, wherein at least one of L ^Q1 to L ^Q6 is F.

Preferred compounds of formula Q are those in which R ^Q represents a straight-chain alkyl group having 2 to 6 C atoms, very preferably ethyl, n-propyl or n-butyl.

Preferred compounds of formula Q are those wherein L ^Q3 and L ^Q4 are F. Further preferred compounds of formula Q are those wherein L ^Q3 , L ^Q4 and one or both of L ^Q1 and L ^Q2 are F.

Preferred compounds of formula Q are those wherein ^XQ represents F or _OCF3 , very preferably F. Compounds of formula Q are preferably selected from the following subformulas: Q1 Q2 wherein R ^Q has one of the meanings of the formula Q or one of its preferred meanings given above and below, and is preferably ethyl, n-propyl or n-butyl.

Especially preferred are compounds of formula Q1, especially those wherein R ^Q is n-propyl.

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

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

The addition of quaterphenyl compounds of formula Q to the LC host mixture can reduce ODF display unevenness while maintaining high UV absorption, achieve fast and complete polymerization, achieve strong and fast tilt angle generation, and improve the UV stability of LC media.

Furthermore, the addition of compounds of formula Q with positive dielectric anisotropy to LC media with negative dielectric anisotropy allows better control over the values of the dielectric constants ε _|| and ε _⊥ , in particular enabling high dielectric The value of the electrical constant ε _|| while keeping the dielectric anisotropy Δε constant reduces the kickback voltage and reduces image sticking.

The LC medium according to the invention preferably comprises - one or more compounds of formula C, preferably of formula C1, in a total concentration in the range of 0.5 to 10% by weight, more preferably 0.5 to 8% by weight, most preferably 1 to 6% by weight; and / or - one or more compounds of formula IIA, preferably compounds of formula IIA-2 or IIA-10, preferably in a total concentration of 4% to 25% by weight, more preferably 5% to 20% by weight, most preferably 6% to 15% by weight %In the range; and / or - one or more compounds of formula IIA and IIB, preferably of formula IIA-2 and/or IIA-10 and/or IIB-10, in a total concentration of 5% to 25% by weight, more preferably 10% to 20% by weight In the range; and / or - one or more compounds of formula IIC, preferably of formula IIC-1, preferably in a total concentration ranging from 0.5% to 10% by weight, more preferably from 0.5 to 5% by weight; and / or - one or more compounds of formula IID, preferably of formula IID-4, preferably in a total concentration ranging from 5 to 40% by weight, more preferably from 10 to 30% by weight; and / or - one or more compounds of formula III-2, preferably of formula III-2-6, preferably in a total concentration ranging from 2% to 25% by weight, more preferably from 5% to 15% by weight; and / or - one or more compounds of formula IV, preferably compounds of formula IV-3, preferably in a total concentration ranging from 35% to 70% by weight, more preferably from 40% to 55% by weight; and / or - one or more compounds of formula IIA-Y, preferably compounds of formula IIA-Y6a, preferably in a total concentration ranging from 1% to 15% by weight, more preferably from 1% to 10% by weight, most preferably from 2% to 6% by weight Inside; In a particularly preferred embodiment, the medium comprises - one or more compounds CY-n-Om, especially CY-3-O4, CY-5-O4 and/or CY-3-O2, preferably in a total concentration ranging from 5% to 30% by weight, preferably 10% by weight % to 20% by weight; and / or - one or more compounds PY-n-Om, in particular PY-3-O2 and/or PY-1-O2, preferably in a total concentration in the range of 5% to 30% by weight, preferably 5% to 20% by weight ; and / or - one or more compounds CPY-n-Om, in particular CPY-2-O2, CPY-3-O2 and/or CPY-5-O2, preferably in a concentration ≥ 5% by weight, especially 7 to 20% by weight, based on the entire mixture; and / or - one or more compounds CCY-n-Om, especially CCY-4-O2, CCY-3-O2, CCY-3-O3, CCY-3-O1 and/or CCY-5-O2, preferably in a concentration ≥ 3 wt. %, especially 5 to 15% by weight, based on the entire mixture; and / or - CLY-n-Om, preferably CLY-2-O4, CLY-3-O2 and/or CLY-3-O3, preferably in a concentration ≥ 5% by weight, in particular 10 to 30% by weight, very preferably 15 to 25% by weight , based on the entire mixture; and / or - CPY-n-Om and CY-n-Om, preferably in a concentration of 10 to 40% by weight, based on the entire mixture; and / or - CPY-n-Om and PY-n-Om, preferably CPY-2-O2 and/or CPY-3-O2 and PY-3-O2 or PY-1-O2, preferably in a concentration of 5% to 20% by weight , more preferably from 10 to 15% by weight, based on the entire mixture; and / or - CC-3-V, preferably in a total concentration ranging from 15 to 60% by weight, more preferably from 25 to 55% by weight, most preferably from 35 to 50% by weight; and / or - CC-3-V1, preferably with a total concentration in the range of 1 to 20% by weight, more preferably 1 to 15% by weight, most preferably 1 to 10% by weight, and / or - one or more compounds of formula B-nO-Om and/or B(S)-nO-Om, especially compounds B(S)-2O-O4 and/or B(S)-2O-O5 and/or B (S)-2O-O5, preferably in a total concentration ranging from 2 to 25% by weight, more preferably from 5 to 15% by weight; and / or - PYP-n-m, preferably PYP-2-3 and/or PYP-2-4, preferably in a total concentration ranging from 0.5 to 10% by weight, more preferably from 0.5 to 5% by weight; and / or - Y-nO-Om, preferably Y-4O-O4, in a total concentration ranging from 1 to 25%, more preferably from 1 to 10%, most preferably from 2 to 6% by weight; - PYP-n-m, preferably PYP-2-3 and/or PYP-2-4, preferably in a total concentration in the range of 0.5 to 10% by weight, more preferably 0.5 to 5% by weight.

Furthermore, the invention relates to an electro-optic display with active matrix addressing, characterized in that it comprises an LC medium as claimed in claim 1 as dielectric, and wherein the display is VA, SA-VA, IPS, U-IPS, FFS, UB- FFS, SA-FFS, PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS, PS-posi-VA, PS-TN, polymer stabilized SA-VA or polymer stabilized Optimized SA-FFS display.

The LC medium preferably has a nematic LC phase.

It is advantageous for the liquid-crystalline media according to the invention to preferably have a nematic phase of ≤-20°C to ≥70°C, particularly preferably ≤-30°C to ≥75°C, very particularly preferably ≤-40°C to ≥80°C.

The media according to the invention preferably have a clear temperature of 70° C. or higher, preferably 80° C. or higher.

The expression "having a nematic phase" here means on the one hand that at low temperatures no smectic phase and no crystallization are observed at the corresponding temperature and on the other hand that heating from the nematic phase does not become clear. The low-temperature studies were carried out in a flow viscometer at the corresponding temperature and checked by storage in test boxes with a layer thickness corresponding to at least 100 hours of electro-optic use. A medium is said to be stable at -20°C if the storage capacity in the corresponding test cartridge is 1000 h or more at a temperature of -20°C. At a temperature of -30°C or -40°C, the corresponding times were 500 h or 250 h, respectively. At high temperatures, the clearing point is measured in capillaries by traditional methods.

The liquid-crystalline mixture preferably has a nematic phase range of at least 60 K and a fluid viscosity v ₂₀ of at most 30 mm ² ·s ⁻¹ at 20° C.

The mixture is nematic at a temperature of -20°C or lower, preferably -30°C or lower, very preferably -40°C or lower.

The birefringence value Δn in liquid-crystalline mixtures is generally from 0.07 to 0.16, preferably from 0.08 to 0.15, very preferably from 0.09 to 0.14.

In a preferred embodiment of the invention, the medium has a birefringence in the range from 0.0850 to 0.110, preferably from 0.090 to 0.1050.

The liquid-crystal mixtures according to the invention have a dielectric anisotropy Δε of −1.5 to −8.0, preferably −2.0 to −4.0, in particular −2.5 to −3.5.

The rotational viscosity _γ1 at 20° C. is preferably ≤ 110 mPa·s, especially ≤ 100 mPa·s.

In a preferred embodiment, the rotational viscosity _γ1 is ≤ 95 mPa·s, especially ≤ 90 mPa·s at 20°C.

The liquid-crystalline media according to the invention have relatively low threshold voltage values (V ₀ ). It is preferably in the range of 1.7V-3.0V, particularly preferably ≦2.7V and very particularly preferably ≦2.5V.

For the purposes of the present invention, the term "threshold voltage" relates to the capacitive threshold (V ₀ ), also known as the Freedericks threshold, unless expressly stated otherwise.

In addition, the liquid-crystalline media according to the invention have high voltage retention values in liquid crystal cells.

In general, liquid crystal media with low addressing or threshold voltages exhibit lower voltage retention than those with higher addressing or threshold voltages, and vice versa.

For the purposes of this invention, the term "dielectrically positive compounds" means compounds with Δε>1.5, the term "dielectric neutral compounds" means those with -1.5≤Δε≤1.5 and the term "dielectrically negative compounds" means compounds with Δε<- 1.5 of those. Here, the dielectric anisotropy of the compounds was determined by dissolving 10% of the compounds in the LC body in at least one test cell, in each case with a layer thickness of 20 µm and at With homeotropic and along-plane surface alignment at 1 kHz. The measured voltages were typically 0.5 V-1.0 V, but were always below the capacitive threshold of the respective liquid crystal mixtures studied.

All temperature values stated in the present invention are expressed in °C.

LC media according to the invention are suitable for all VA-TFT (Vertical Alignment Thin Film Transistor) applications, e.g. VAN (Vertical Alignment Nematic), MVA (Multi-Domain VA), (S)-PVA (Super Patterned VA) , ASV (Advanced Super View or Axisymmetric VA), PSA (Polymer Stabilized VA) and PS-VA (Polymer Stabilized VA). Furthermore, they are suitable for IPS (In-Plane Switching) and FFS (Fringe Field Switching) applications with negative Δε.

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

Component A has a pronounced negative dielectric anisotropy and imparts a dielectric anisotropy of ≤ -0.5 to the nematic phase. Besides one or more compounds of formula C, it preferably comprises compounds of formula IIA, IIB and/or IIC, and one or more compounds of formula IV-1.

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

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

Component B has significant nematogeneity and a fluid viscosity at 20°C of not more than 30 mm ² ·s ^‑1 , preferably not more than 25 mm ² ·s ^‑1 .

A wide variety of suitable substances will be known to those skilled in the art from the literature. Particularly preferred are compounds of formula O-17.

Particularly preferred individual compounds in component B are very low-viscosity nematic liquid crystals having a flow viscosity at 20° C. of not more than 18 mm ² ·s ^—1 , preferably not more than 12 mm ² ·s ^—1 .

Component B is a unidirectional or interconverting nematic phase, has no smectic phase and prevents the appearance of a smectic phase in LC media down to very low temperatures. For example, if multiple high nematic materials are added to a smectic liquid crystal mixture, the nematicities of these materials can be compared by the degree of suppression of the smectic phase achieved.

The mixture may optionally also comprise a component C comprising compounds having a dielectric anisotropy of Δε≧1.5. These so-called positive compounds are generally present in negative dielectrically anisotropic mixtures in an amount of ≦20% by weight, based on the total mixture.

In addition to one or more compounds of the formula C, the medium preferably also contains 4 to 15, in particular 5 to 12, particularly preferably ≦10 compounds of the formulas IIA, IIB, IIC and/or IID, 1 to 5, preferably 1 , 2 or 3 compounds of formula III and optionally one or more compounds of formula IV.

In addition to the compound of formula C and the compound of formula IIA, IIB, IIC, IID, III and optionally IV, further constituents may also be present, for example in up to 45%, but preferably ≦35%, in particular ≦10% of the total mixture The amount of % exists.

The other constituents are preferably selected from nematic or nematic substances, in particular known substances selected from azobenzene oxide, benzylidene aniline, biphenyl, terphenyl, phenyl or cyclohexyl benzoate, cyclohexyl Phenyl or cyclohexyl alkanecarboxylate, phenylcyclohexane, cyclohexylbiphenyl, cyclohexylcyclohexane, cyclohexylnaphthalene, 1,4-dicyclohexylbiphenyl or cyclohexylpyrimidine, phenyldioxane or cyclohexyldioxane, optionally halogenated stilbenes, benzyl phenyl ethers, tolanes and substituted cinnamates.

The most important compounds suitable as components of liquid crystal phases of this type can be characterized by the formula OC R ²⁰ -LGER ²¹ OC where L and E each represent a group selected from 1,4-disubstituted benzene and cyclohexane rings, 4,4' -Disubstituted biphenyl, phenylcyclohexane and cyclohexylcyclohexane systems, 2,5-disubstituted pyrimidine and 1,3-dioxane rings, 2,6-disubstituted naphthalene, dihydronaphthalene and tetrahydro Carbocyclic or heterocyclic ring systems of naphthalene, quinazoline and tetrahydroquinazoline, G means -CH=CH-, -N(O)=N-, -CH=CQ-, -CH=N(O)- , -C≡C-, -CH ₂ -CH ₂ -, -CO-O-, -CH ₂ -O-, -CO-S-, -CH ₂ -S-, -CH=N-, -COO- Phe-COO-, -CF ₂ O-, -CF=CF-, -OCF ₂ -, -OCH ₂ -, -(CH ₂ ) ₄ -, -(CH ₂ ) ₃ O-, or CC single bond, Q represents halogen, preferably chlorine, ^or -CN, and R and ^R each represent alkyl, alkenyl, alkoxy, alkoxyalkyl or alkoxycarbonyl having up to 18, preferably up to 8, carbon atoms Oxy, or one of these groups also represents CN, NC, NO ₂ , NCS, CF ₃ , SF ₅ , OCF ₃ , F, Cl or Br.

In most of these compounds, ^R20 and ^R21 are different from each other and one of these groups is usually an alkyl or alkoxy group. Other variations of the proposed substituents are also common. Many such materials or mixtures thereof are commercially available. All these substances can be prepared by methods known from the literature.

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

The combination of the compounds of the above-mentioned preferred embodiments with the above-mentioned polymeric compounds leads in the LC media according to the invention to low threshold voltages, low rotational viscosities and very good low-temperature stability, while sustaining high clearing points and high HR values, and allows Particularly low tilt angles (i.e. large tilts) are quickly established in PSA displays. In particular, in PSA displays, the LC media exhibit significantly shortened response times, in particular grayscale response times, compared to LC media from the prior art.

The LC media according to the invention may also comprise further additives known to the person skilled in the art and described in the literature, such as polymerization initiators, inhibitors, stabilizers, surface-active substances or chiral dopants. These can be polymerizable or non-polymerizable.

In a preferred embodiment of the invention, the LC medium additionally comprises one or more polymerizable compounds.

The polymerizable compound is preferably selected from the formula M R ^a -B ¹ -(Z ^b -B ² ) _m -R ^b M in which the individual radicals have the following meanings at each occurrence, identically or differently and each independently of the other: R ^a and R ^b is P, P-Sp-, H, F, Cl, Br, I, -CN, -NO ₂ , -NCO, -NCS, -OCN, -SCN, SF ₅ or 1 to 25 C atoms Straight-chain or branched-chain alkyl, wherein, in addition, one or more non-adjacent _CH groups can each be independently of one another by -C(R ⁰ )=C(R ⁰⁰ )-, -C≡C-, -N(R ⁰⁰ )‑, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- such that the O and/or S atoms are not directly connected to each other The way of connection is replaced, and, wherein, in addition, one or more H atoms can be replaced by F, Cl, Br, I, CN, P or P-Sp-, wherein, if B ¹ and/or B ² contain saturated C atom, then R ^a and/or R ^b may also represent a group spiro-bonded to this saturated C atom, wherein at least one of the groups R ^a and R ^b represents P or P-Sp- or comprises the group P or P-Sp-, P is a polymerizable group, Sp is a spacer group or a single bond, B ^{and B} are aromatic, heteroaromatic, cycloaliphatic or heterocyclic rings preferably having 4 to 25 ring atoms A group, which may also contain fused rings, and which is unsubstituted, or monosubstituted or polysubstituted by L, Z ^b is -O-, -S-, -CO-, -CO-O-, -OCO ‑, -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‑, -C≡C -, -CH=CH-COO-, -OCO-CH=CH-, CR ⁰ R ⁰⁰ or a single bond, R ⁰ and R ⁰⁰ each independently represent H or an alkyl group having 1 to 12 C atoms, m means 0, 1, 2, 3 or 4, n1 means 1, 2, 3 or 4, L means P, P‑Sp‑, OH, CH ₂ OH, F, Cl, Br, I, -CN, -NO ₂ , -NCO, -NCS, -OCN, -SCN, -C(=O)N(R ^x ) ₂ , -C(=O)Y ¹ , -C(=O)R ^x , -N(R ^x ) _2. An optionally substituted silyl group, an optionally substituted aryl group having 6 to 20 C atoms, or a linear or branched alkyl group or alkoxy group having 1 to 25 C atoms, Alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, wherein, in addition, one or more H atoms can be replaced by F, Cl, P or P-Sp-, P and Sp have The above-mentioned meanings, Y ¹ represents halogen, R ^x represents P, P-Sp-, H, halogen, straight chain, branched chain or cyclic alkyl with 1 to 25 C atoms, wherein, in addition, one or Multiple non-adjacent CH _groups can 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, wherein, in addition, one or more H atoms can be replaced by F, Cl, P or P-Sp-, optionally substituted aryl or aryl oxygen having 6 to 40 C atoms radical, or an optionally substituted heteroaryl or heteroaryloxy group having 2 to 40 C atoms.

Particularly preferred compounds of formula M are those wherein B ^and B ^each independently represent 1,4-phenylene, 1,3-phenylene, naphthalene-1,4-diyl, naphthalene-2,6 -diyl, phenanthrene-2,7-diyl, 9,10-dihydro-phenanthrene-2,7-diyl, anthracene-2,7-diyl, fluorene-2,7-diyl, coumarin , flavones, wherein, in addition, one or more CH groups in these groups may be replaced by N, cyclohexane-1,4-diyl, wherein, in addition, one or more non-adjacent CH _groups The group can be replaced by O and/or S, 1,4-cyclohexenyl, 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, indan-2,5-diyl or octahydro-4,7-methanoindan-2,5-diyl, all of which may be unsubstituted or Mono- or poly-substituted by L as defined above.

Particularly preferred compounds of formula M are those wherein B ^and B ^each independently represent 1,4-phenylene, 1,3-phenylene, naphthalene-1,4-diyl or naphthalene-2,6-di base ones.

Very preferred compounds of formula M are selected from the following formulae: M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11 M12 M13 M14 M15 M16 M17 M18 M19 M20 M21 M22 M23 M24 M25 M26 M27 M28 M29 M30 M31 M32 wherein each group has the following meanings at each occurrence identically or differently and independently of each other: P ¹ , P ² , P ³ are polymerizable groups, preferably selected from ethyleneoxy, acrylate, methyl acrylate group, fluoroacrylate group, chloroacrylate group, oxetanyl group or epoxy group, Sp ¹ , Sp ² and Sp ³ are single bonds or spacer groups, wherein in addition, the group P ¹ -Sp One or more of ¹ -, P ² -Sp ² - and P ³ -Sp ³ - may also represent R ^aa , provided that the groups P ¹ -Sp ¹ -, P ² -Sp ² and P ³ - At least one of Sp ³ - is different from R ^aa , preferably -(CH ₂ ) _p1 -, -(CH ₂ ) _p1 -O-, -(CH ₂ ) _p1 -CO-O- or (CH ₂ ) _p1 - O-CO-O-, wherein p1 is an integer from 1 to 12. R ^aa represents H, F, Cl, CN or a linear or branched chain alkyl group having 1 to 25 C atoms, wherein, in addition, one or more non-adjacent _CH groups can each be independently of each other by - C(R ⁰ )=C(R ⁰⁰ )‑, -C≡C‑, -N(R ⁰ )‑, -O‑, -S‑, -CO‑, -CO-O‑, -O-CO‑ , -O-CO-O- are substituted in such a way that the O and/or S atoms are not directly connected to each other, and, wherein, in addition, one or more H atoms may be replaced by F, Cl, CN or P ¹ -Sp ¹ - Instead, particular preference is given to straight-chain or branched, optionally mono- or polyfluorinated, alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, having 1 to 12 C atoms, Alkylcarbonyloxy or alkoxycarbonyloxy (wherein alkenyl and alkynyl groups have at least two C atoms, and branched groups have at least three C atoms), R ⁰ , R ⁰⁰ is H or has Alkyl group with 1 to 12 C atoms, R ^y and R ^z are H, F, CH ₃ or CF ₃ , Z ^M1 is -O-, -CO-, -C(R ^y R ^z )- or -CF ₂ CF ₂ -, Z ^M2 , Z ^M3 are -CO-O-, -O-CO-, -CH ₂ O-, -OCH ₂ -, -CF ₂ O-, -OCF ₂ - or -(CH ₂ ) _n -, wherein n is 2, 3 or 4, L is F, Cl, CN or a linear or branched, optionally mono- or polyfluorinated alkyl, alkoxy having 1 to 12 C atoms , alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, L', L'' are H, F or Cl, k is 0 or 1, r is 0, 1, 2, 3 or 4, s is 0, 1, 2 or 3, t is 0, 1 or 2, x is 0 or 1.

Very preferred are compounds of the formulas M2 and M13, especially direactive compounds containing exactly two polymerizable groups ^P1 and ^P2 .

Further preference is given to compounds selected from the formulas M17 to M32, especially from the formulas M17, M22, M24, M27, M30 and M32, especially three tripolymers containing exactly three polymerizable groups ^P1 , ^P2 and ^P3 reactive compound.

In compounds of formulas M1 to M32, the group preferably or wherein L has at each occurrence identically or differently one of the meanings given above and below, and is preferably F, Cl, CN, NO ₂ , CH ₃ , C ₂ H ₅ , C(CH ₃ ) ₃ , CH( CH ₃ ) ₂ , CH ₂ CH(CH ₃ )C ₂ H ₅ , OCH ₃ , OC ₂ H ₅ , COCH ₃ , COC ₂ H ₅ , COOCH ₃ , COOC ₂ H ₅ , CF ₃ , OCF ₃ , OCHF ₂ , _OC2F5 or _P - _Sp- , very preferably F, Cl, CN, _CH3 , _C2H5 , OCH3, _COCH3 , _OCF3 or P _- Sp-, more preferably F, Cl, _CH3 , OCH _3. COCH ₃ or OCF ₃ , most preferably F or OCH ₃ .

Preferred compounds of the formulas M1 to M32 are those in which P ¹ , P ² and P ³ represent an acrylate, methacrylate, oxetanyl or epoxy group, very preferably an acrylate or methacrylate group, Most preferred are those compounds based on methacrylate groups.

Further preferred compounds of the formulas M1 to M32 are those in which Sp ¹ , Sp ² and Sp ³ are single bonds.

Further preferred compounds of the formulas M1 to M32 are those wherein one of Sp ¹ , Sp ² and Sp ³ is a single bond and the other of Sp ¹ , Sp ² and Sp ³ is different from a single bond.

Further preferred compounds of the formulas M1 to M32 are those in which those radicals Sp ¹ , Sp ² and Sp ³ other than single bonds represent -(CH ₂ ) _s1 -X"-, where s1 is an integer from 1 to 6, 2, 3, 4 or 5 are preferred, and X" is a linker to the benzene ring and is -O-, -O-CO-, -CO-O, -O-CO-O- or a single bond.

Further preferred compounds of formula M are those selected from the following table D, especially selected 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-58, RM-64, RM-74, RM-76, RM-88, RM-91, RM-102, RM-103, RM-109, RM-116, RM-117, RM-120, RM-121, RM-122, RM-139, RM-140, RM-142, RM-143, RM- 145, RM-146, RM-147, RM-149, RM-156 to those of RM-163, RM-169, RM-170 and RM-171 to RM-183.

Particular preference is given to liquid-crystalline media comprising one, two or three polymerizable compounds of the formula M.

Further preferred are LC media comprising two or more bireactive polymerizable compounds of the formula M, preferably selected from the formulas M1 to M16, very preferably selected from the formulas M2 and M13.

Further preference is given to comprising one or more direactive polymerizable compounds of the formula M, preferably selected from the formulas M1 to M16, very preferably selected from the formulas M2 and M13, and one or more formulas M, preferably selected from the formulas M17 to M32, Very preferred are LC media of three reactive polymerizable compounds selected from the group consisting of formulas M20, M22, M24, M27, M30 and M32.

Further preferred are LC media comprising one or more polymerizable compounds of formula M, wherein at least one r is different from 0, or at least one of s and t is different from 0, very preferably selected from the formulas M2, M13, M22, M24 , M27, M30 and M32, wherein L is selected from the preferred groups shown above, most preferably from F and _OCH3 .

Further preferred polymerizable compounds are listed in Table D below.

Further preferred are polymerizable compounds showing absorption in the wavelength range from 320 to 380 nm, preferably selected from formula M, very preferably selected from formulas M1 to M32, more preferably selected from the above formulas of Table D, most preferably selected from 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, R-139 , RM-142 and RM-171 to RM-183.

Further preferred second polymerizable compounds are selected from the compounds used in the mixture examples below.

Preferably, the proportion of polymerisable compound in the LC medium is from 0.01 to 2%, very preferably from 0.05 to 1%, most preferably from 0.1 to 0.5%.

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-like reactions, such as addition or condensation on the polymer backbone. Particularly preferred are groups for chain polymerization, especially those containing C=C double bonds or -C≡C- triple bonds, and groups suitable for ring-opening polymerization, for example, oxetanyl or ring Oxygen.

Preferred P groups are selected from the group consisting of CH ₂ =CW ¹ -CO-O-, CH ₂ =CW ¹ -CO-, , , , , CH ₂ =CW ² -(O) _k3 -, CW ¹ =CH-CO-(O) _k3 -, CW ¹ =CH-CO-NH-, CH ₂ =CW ¹ -CO-NH-, CH ₃ - CH=CH-O-, (CH ₂ =CH) ₂ CH-OCO-, (CH ₂ =CH-CH ₂ ) ₂ CH-OCO-, (CH ₂ =CH) ₂ CH-O-, (CH ₂ = CH-CH ₂ ) ₂ N-, (CH ₂ =CH-CH ₂ ) ₂ N-CO-, HO-CW ² W ³ -, HS-CW ² W ³ -, HW ² N-, HO-CW ² W ³ -NH-, CH ₂ =CW ¹ -CO-NH-, CH ₂ =CH-(COO) _k1 -Phe-(O) _k2 -, CH ₂ =CH-(CO) _k1 -Phe-(O) _k2 -, Phe-CH=CH-, HOOC-, OCN- and W ⁴ W ⁵ W ⁶ Si-, wherein W ¹ represents H, F, Cl, CN, CF ₃ , phenyl or C-atoms with 1 to 5 Alkyl, especially H, F, Cl or CH ₃ , W ² and W ³ each independently of the other represent H or an alkyl group having 1 to 5 carbon atoms, especially H, methyl, ethyl or n-propyl , W ⁴ , W ⁵ and W ⁶ each independently represent Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W ⁷ and W ⁸ each independently represent H, Cl or have Alkyl group with 1 to 5 C atoms, Phe denotes 1,4-phenylene, which is optionally substituted by one or more of the above-defined groups L other than P-Sp-, k ₁ , k ₂ and k ₃ each independently represent 0 or 1, k ₃ preferably represents 1, and k ₄ represents an integer of 1-10.

Very preferred P groups are selected from the group consisting of: CH ₂ =CW ¹ -CO-O-, CH ₂ =CW ¹ -CO-, , , , , CH ₂ =CW ² -O-, CH ₂ =CW ² -, CW ¹ =CH-CO-(O) _k3 -, CW ¹ =CH-CO-NH-, CH ₂ =CW ¹ -CO-NH- , (CH ₂ =CH) ₂ CH-OCO-, (CH ₂ =CH-CH ₂ ) ₂ CH-OCO-, (CH ₂ =CH) ₂ CH-O-, (CH ₂ =CH-CH ₂ ) ₂ N-, (CH ₂ =CH-CH ₂ ) ₂ N-CO-, CH ₂ =CW ¹ -CO-NH-, CH ₂ =CH-(COO) _k1 -Phe-(O) _k2 -, CH ₂ = CH-(CO) _k1 -Phe-(O) _k2 -, Phe-CH=CH- and W ⁴ W ⁵ W ⁶ Si-, wherein W ¹ represents H, F, Cl, CN, CF ₃ , phenyl or has Alkyl of 1 to 5 C atoms, in particular H, F, Cl or CH ₃ , W ² and W ³ each independently represent H or an alkyl group with 1 to 5 C atoms, in particular H, methyl , ethyl or n-propyl, W ⁴ , W ⁵ and W ⁶ each independently represent Cl, an oxaalkyl or oxacarbonylalkyl group having 1 to 5 C atoms, W ⁷ and W ⁸ each independently of each other represents H, Cl or an alkyl group having 1 to 5 C atoms, Phe represents 1,4-phenylene, k ₁ , k ₂ and k ₃ each independently represent 0 or 1, k ₃ preferably represents 1 , and k ₄ represents an integer of 1-10.

Very particularly preferred P groups are selected from the group consisting of _CH2 = ^CW1 -CO-O-, especially _CH2 =CH-CO-O-, _CH2 =C( _CH3 )-CO-O- and CH ₂ =CF-CO-O-, and CH ₂ =CH-O-, (CH ₂ =CH) ₂ CH-O-CO-, (CH ₂ =CH) ₂ CH-O-, and .

Further preferred polymerizable groups P are selected from the group consisting of ethyleneoxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetanyl and epoxy, most preferably from acrylate and methacrylate groups.

If Sp is different from a single bond, it is preferably of the formula Sp"-X", so that the corresponding group P-Sp- corresponds to the formula P-Sp"-X", where Sp" means having 1 to 20 C atoms, Preference is given to alkylene groups of 1 to 12 C atoms, which are optionally mono- or polysubstituted by F, Cl, Br, I or CN, and wherein in addition, one or more non-adjacent _CH groups can each independently of each other by -O-, -S-, -NH-, -N(R ⁰ )-, -Si(R ⁰ R ⁰⁰ )-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -S-CO-, -CO-S-, -N(R ⁰⁰ )-CO-O-, -O-CO-N(R ⁰ )-, -N(R ⁰ ) -CO-N(R ⁰⁰ )-, -CH=CH- or ‑C≡C- are replaced in such a way that O and/or S atoms are not directly connected to each other, X" means -O-, -S-, -CO -, -CO-O-, -O-CO-, -O-CO-O-, -CO-N(R ⁰ )-, N(R ⁰ )-CO-, -N(R ⁰ )-CO- N(R ⁰⁰ )-, -OCH ₂ -, -CH ₂ O-, -SCH ₂ -, -CH ₂ S-, CF ₂ O-, -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 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 have 1 to 20 The alkyl group of the C atom, and Y ² and Y ³ each independently represent H, F, Cl or CN, and X" is preferably -O-, -S-, -CO-, -COO-, -OCO-, - O-COO‑, ‑CO-NR ⁰ ‑, ‑NR ⁰ -CO‑, ‑NR ⁰ -CO-NR ⁰⁰ - or single bond.

Typical _spacers Sp and -Sp"-X" are, for example -( _{CH2 ) p1-} , -( _CH2CH2O ) _q1 - _CH2CH2- , _{-CH2CH2 -} S- _{CH2CH 2} ‑, -CH ₂ CH ₂ -NH-CH ₂ CH ₂ - or -(SiR ⁰ R ⁰⁰ -O) _p1 ‑, where p1 is an integer of 1-12, q1 is an integer of 1-3, R ⁰ and R ⁰⁰ has the above meaning.

Particularly preferred groups Sp and -Sp"-X" are -(CH ₂ ) _p1 -, -(CH ₂ ) _p1 -O-, -(CH ₂ ) _p1 -O-CO-, -(CH ₂ ) _p1 -CO-O-, -(CH ₂ ) _p1 -O-CO-O-, wherein p1 and q1 have the abovementioned meanings.

Particularly preferred radicals Sp" are in each case straight-chain ethylidene, propylidene, butylene, pentylene, hexylene, heptyl, octyl, nonylene, decylene , undecyl, dodecyl, octadecyl, ethyloxyethyl, methyloxybutyl, ethylthioethyl, ethyl-N-methyl imino-ethylene, 1-methylalkylene, vinylene, propenyl and butenyl.

To produce a PSA or PS-VA display, the polymerizable compounds contained in the LC medium are polymerized or crosslinked by in situ polymerization in the LC medium between the substrates of the LC display (if a compound contains two or more polymeric groups), optionally simultaneously applying a voltage to the electrodes.

The structure of the PSA display according to the invention corresponds to the usual geometry of PSA displays, as described in the prior art cited at the outset. Geometries without protrusions are preferred, in particular those in which the electrodes on the color filter side are otherwise unstructured and only the electrodes on the TFT side have grooves. Particularly suitable and preferred electrode structures for PS-VA displays are described, for example, in US 2006/0066793 A1.

In a preferred embodiment, the LC medium comprises one or more polymerization initiators. Suitable conditions for the polymerization and suitable types and amounts of initiators are known to those skilled in the art and are described in the literature. Suitable for free-radical polymerization are, for example, the commercially available photoinitiators Irgacure 651®, Irgacure 184®, Irgacure 907®, Irgacure 369® or Darocure 1173® (Ciba AG). If a polymerization initiator is used, its proportion is preferably 0.001 to 5% by weight, particularly preferably 0.001 to 1% by weight.

The polymerizable compounds according to the invention are also suitable for polymerization without initiators, which is accompanied by considerable advantages, such as lower material costs and in particular the possible residual amounts of initiators or their degradation products on the LC medium. pollute.

The polymerization can thus also be carried out without the addition of initiators. Therefore, in another preferred embodiment, the LC medium is free of polymerization initiators.

In another preferred embodiment, the LC medium additionally comprises one or more stabilizers to prevent undesired spontaneous polymerization of the RM, for example during storage or transport. Suitable stabilizer types and amounts are known to those skilled in the art and are described in the literature. Particularly suitable are, for example, commercially available stabilizers from the Irganox® series (Ciba AG), eg Irganox® 1076. If stabilizers are used, their proportion is preferably from 10 to 50,000 ppm, particularly preferably from 50 to 5,000 ppm, based on the total amount of RM or polymerizable components (component A).

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

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

The LC medium may also contain one or more stabilizers. Suitable stabilizer types and amounts are known to those skilled in the art and are described in the literature. Particularly suitable are, for example, commercially available stabilizers from the Irganox® series (Ciba AG), eg Irganox® 1076. If stabilizers are used, their proportion is preferably 10-500,000 ppm, more preferably 50-5,000 ppm, very preferably 50-1,000 ppm.

In another preferred embodiment of the invention, the LC medium contains one or more stabilizers selected from the following formulae: S1 S2 S3 wherein the individual ^radicals independently of one another and at each occurrence identically or differently have the following meanings: group, most preferably methyl, X ^S is H, CH ₃ , OH or O ^● , ^AS is an optionally substituted linear, branched or cyclic alkylene group with 1 to 20 C atoms, n is 1 An integer of up to 6, preferably 3.

Preferred stabilizers of formula S3 are selected from formula S3A: S3A wherein n2 is an integer from 1 to 12, and wherein one or more H atoms in the group ( _CH2 ) _n2 are optionally replaced by methyl, ethyl, propyl, butyl, pentyl or hexyl.

Very preferred stabilizers are selected from the formula: S1-1 S2-1 S3-1 S3-2 S3-3 S3-4 S3-5 S3-6 S3-7

In a preferred embodiment, the LC medium comprises one or more stabilizers selected from formulas S1-1, S2-1, S3-1, S3-2 and S3-3.

In a preferred embodiment, the LC medium comprises one or more stabilizers selected from Table C below.

Preferably, the proportion of stabilizers (for example those of the formulas S1-S3) in the LC medium is from 10 to 500 ppm, very preferably from 20 to 100 ppm.

In another preferred embodiment, the LC media according to the invention comprise self-aligning (SA) additives, preferably in a concentration of 0.1 to 5%, very preferably 0.1 to 3%, more preferably 0.1 to 2.5%, most preferably 0.2 to 2.5% .

In a preferred embodiment, the SA-VA display according to the invention does not comprise a polyimide alignment layer.

In another preferred embodiment, the SA-VA display according to the preferred embodiment comprises a polyimide alignment layer.

Preferred SA additives for this preferred embodiment are selected from linear or branched alkyl groups comprising mesogenic groups and terminated with one or more polar anchor groups selected from hydroxyl, carboxyl, amine or thiol groups Compounds with side chains.

Further preferred SA additives comprise one or more polymerizable groups, optionally linked to the mesogenic group via a spacer group. These polymerizable SA additives can be polymerized in LC medium under similar conditions to those applied to RM in PSA process.

Suitable SA additives for inducing homeotropic alignment, especially for use in SA-VA mode displays are disclosed eg in US 2013/0182202 A1 , US 2014/0838581 A1 , US 2015/0166890 A1 and US 2015/0252265 A1 .

In another preferred embodiment, the LC medium or polymer-stabilized SA-VA display according to the invention comprises one or more self-aligning additives selected from Table E below.

Preference is given to LC media with a nematic LC phase and preferably without a chiral liquid crystalline phase.

Furthermore, it is possible to add, for example, 0-15% by weight of pleochroic dyes to the LC medium, as well as nanoparticles, conductive salts, preferably ethyldimethyldodecylammonium 4-hexyloxybenzoate, tetraphenyl Tetrabutylammonium borate or complex salts of crown ethers (see, for example, Haller et al., Mol. Cryst. Liq. Cryst. 24, 249-258 (1973)) to improve conductivity, or to change dielectric properties Anisotropy, viscosity and/or nematic alignment of substances. Substances of this type are described, for example, in DE-A 22 09 127, 22 40 864, 23 21 632, 23 38 281, 24 50 088, 26 37 430 and 28 53 728.

The individual components of the preferred embodiments a)-z) of the LC media according to the invention are known, or a person skilled in the relevant art can easily deduce their preparation from the prior art, since they are based on the criteria described in the literature method. Corresponding compounds of the formula CY are described, for example, in EP-A-0 364 538 . Corresponding compounds of the formula ZK are described, for example, in DE-A-26 36 684 and DE-A-33 21 373 .

The LC media which can be used according to the invention are prepared in a manner customary per se, for example by mixing one or more of the aforementioned compounds with one or more of the polymerizable compounds as defined above and optionally with further liquid crystal compounds and/or additives. In general, the required amount of the components used in smaller amounts is dissolved in the components making up the main ingredient, advantageously at elevated temperature. It is also possible to mix solutions of the components in organic solvents, for example in acetone, chloroform or methanol, and, after thorough mixing, to remove the solvent again, for example by distillation. The invention furthermore relates to a process for producing the LC media according to the invention.

It goes without saying for a person skilled in the art that the LC media according to the invention can also comprise compounds in which for example H, N, O, Cl, F have been replaced by corresponding isotopes such as deuterium or the like.

The construction of the LC display according to the invention, consisting of polarizers, electrode substrates and surface-treated electrodes, corresponds to the usual design of displays of this type. The term "general design" is here broadly described and also includes all derivatives and variants of liquid crystal displays, including in particular matrix display elements based on polysilicon TFTs or MIMs.

The following examples illustrate the invention without limiting it. However, they show the person skilled in the art the concept of preferred mixtures with the compounds preferably used and their corresponding concentrations as well as their combinations with one another. Furthermore, these examples illustrate which properties and combinations of properties are achievable.

In this context, percentage data represent percentages by weight; all temperatures are in degrees Celsius.

Throughout this patent application, the 1,4-cyclohexylene ring and the 1,4-phenylene ring are described as follows: or or or or or The cyclohexylene ring is a trans-1,4-cyclohexylene ring.

Throughout this patent application and examples, the structures of liquid crystal compounds are expressed by means of abbreviations. Unless otherwise stated, the chemical formulas were converted according to Tables I-III. All groups C _n H _2n+1 , C _m H _2m+1 , C _n H _2n , C _m H _2m and C _k H _2k are linear alkyl groups or alkenyl groups respectively, in each case With n, m or k C atoms, n and m independently of each other represent 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, preferably 1, 2, 3, 4 , 5 or 6, and k is 0, 1, 2, 3, 4, 5 or 6. The ring elements of each compound are coded in Table I, the bridging units are listed in Table II and the symbol meanings of the left-hand side chain or right-hand side chain of the compound are given in Table III.

Preferred mixture components are shown in Table A below.

Table A In Table A, m and n are independently an integer from 1 to 12, preferably 1, 2, 3, 4, 5 or 6, k is 0, 1, 2, 3, 4, 5 or 6, And (O)C _m H _2m+1 represents C _m H _2m+1 or OC _m H _2m+1 . AIK-nF AIY-n-Om AY-n-Om B-nO-Om Bn-Om B-3Cy-Om B-3Cy1O-Om B-4Cy-Om B-4Cy1O-Om B-5Cy-Om B-5Cy1O-Om B(S)-nO-Om B(S)-n-Om B(S)-3Cy-Om B(S)-3Cy1O-Om B(S)-4Cy-Om B(S)-4Cy1O-Om B(S)-5Cy-Om B(S)-5Cy1O-Om CB(S)‑n‑(O)m CB-nm CB-n-Om COB-n-Om COB(S)-n-Om PB-nm PB-n-Om BCH-nm BCH-nmF BCN-nm C-1V-V1 CY-n-Om CY-3Cy-Om CY-3Cy1-Om CY(F,Cl)-n-Om CY(Cl,F)-n-Om CCY-n-Om CC1Y-n-Om CC1G-VF CCG-VF CAIY-n-Om CCY(F,Cl)-n-Om CCY(Cl,F)-n-Om CCY-nm CCY-Vm CCY-Vn-m CCY-n-OmV CBC-nmF CBC-nm CCP-Vm CCP-Vn-m CCP-nV-m CCP-nm CPYP-n-(O)m CYYC-nm CCYY-n-(O)m CCY-n-O2V CCH-nOm, CC-n-Om CCC-nm CCC-nV CY-nm CCH-nm, CC-nm CC-nV CC-n-V1 CC-n-Vm CC-VV CC-V-V1 CC-2V-V2 CVC-nm CC-n-mV CC-n-mV1 CCOC-nm CP-nOmFF CH-nm CEY-n-Om CEY-Vn CVY-Vn CY-V-On CY-n-O1V CY-n-OC(CH ₃ )=CH ₂ CCN-nm CY-n-OV CCPC-nm CCY-n-kOm CPY-n-Om CPY-nm CPY-V-Om CQY-n-(O)m CQIY-n-(O)m CCQY-n-(O)m CCQIY-n-(O)m CPQY-n-(O)m CPQIY-n-(O)m CPYG-n-(O)m CCY-V-Om CCY-V2-(O)m CCY-1V2-(O)m CCY-3V-(O)m CCVC-nV CCVC-VV CPGP-nm CY-nV-(O)m CENaph-n-Om COChrom-n-Om COChrom-nm CCOChrom-n-Om CCOChrom-nm CONaph-n-Om CCONaph-n-Om CCNaph-n-Om CNaph-n-Om CETNaph-n-Om CTNaph-n-Om CK-nF CLY-n-Om CLY-nm LYLI-nm CYLI-nm LY-n-(O)m COYOICC-nm COYOIC-nV CCOY-V-O2V CCOY-V-O3V COY-n-Om CCOY-n-Om CCEY-n-Om CZYY‑n-Om D‑nOmFF LB(S)-nT LB(S)-n-OT PCH-nm, CP-nm PCH-nOm, CP-n-Om PGIGI-nF PGP-nm PP-nm PP-n-2V1 PGP-n-2V1 PPP-n-2V1 PGP-n-2V PYP-n-mV PYP-nm PYP-n-Om PGIY-n-Om PPYY-nm YPY-nm YPY-n-mV PY-n-Om PY-nm PY-V2-Om DFDBC-n(O)-(O)m Y-nO-Om Y-nO-OmV Y-nO-OkVm YG-n-Om YG-nO-Om YGI-n-Om YGI-nO-Om YY-n-Om YY-nO-Om PPGU-nF In a preferred embodiment of the invention, the LC media according to the invention comprise one or more compounds selected from Table A.

Table B Table B shows possible chiral dopants that can be added to the LC media according to the invention. C 15 CB 15 CM 21 R/S-811 CM 44 CM 45 CM 47 CN R/S-2011 R/S-3011 R/S-4011 R/S-5011 R/S-1011 The LC medium preferably contains 0 to 10% by weight, in particular 0.01 to 5% by weight, particularly preferably 0.1 to 3% by weight, of dopants. The LC medium preferably comprises one or more dopants selected from the compounds of Table B.

Table C Table C shows possible stabilizers that can be added to the LC media according to the invention. wherein n represents an integer of 1 to 12, preferably 1, 2, 3, 4, 5, 6, 7 or 8, and no terminal methyl group is shown. The LC medium preferably contains 0 to 10% by weight, in particular 1 ppm to 5% by weight, particularly preferably 1 ppm to 1% by weight, of stabilizer. The LC medium preferably comprises one or more stabilizers selected from the compounds of Table C.

Table D Table D shows exemplary reactive mesogenic compounds that can be used in LC media according to the invention. RM-1 RM-2 RM-3 RM-4 RM-5 RM-6 RM-7 RM-8 RM-9 RM-10 RM-11 RM-12 RM-13 RM-14 RM-15 RM-16 RM-17 RM-18 RM-19 RM-20 RM-21 RM-22 RM-23 RM-24 RM-25 RM-26 RM-27 RM-28 RM-29 RM-30 RM-31 RM-32 RM-33 RM-34 RM-35 RM-36 RM-37 RM-38 RM-39 RM-40 RM-41 RM-42 RM-43 RM-44 RM-45 RM-46 RM-47 RM-48 RM-49 RM-50 RM-51 RM-52 RM-53 RM-54 RM-55 RM-56 RM-57 RM-58 RM-59 RM-60 RM-61 RM-62 RM-63 RM-64 RM-65 RM-66 RM-67 RM-68 RM-69 RM-70 RM-71 RM-72 RM-73 RM-74 RM-75 RM-76 RM-77 RM-78 RM-79 RM-80 RM-81 RM-82 RM-83 RM-84 RM-85 RM-86 RM-87 RM-88 RM-89 RM-90 RM-91 RM-92 RM-93 RM-94 RM-95 RM-96 RM-97 RM-98 RM-99 RM-100 RM-101 RM-102 RM-103 RM-104 RM-105 RM-106 RM-107 RM-108 RM-109 RM-110 RM-111 RM-112 RM-113 RM-114 RM-115 RM-116 RM-117 RM-118 RM-119 RM-120 RM-121 RM-122 RM-123 RM-124 RM-125 RM-126 RM-127 RM-128 RM-129 RM-130 RM-131 RM-132 RM-133 RM-134 RM-135 RM-136 RM-137 RM-138 RM-139 RM-140 RM-141 RM-142 RM-143 RM-144 RM-145 RM-146 RM-147 RM-148 RM-149 RM-150 RM-151 RM-152 RM-153 RM-154 RM-155 RM-156 RM-157 RM-158 RM-159 RM-160 RM-161 RM-162 RM-163 RM-164 RM-165 RM-166 RM-167 RM-168 RM-169 RM-170 RM-171 RM-172 RM-173 RM-174 RM-175 RM-176 RM-177 RM-178 RM-179 RM-180 RM-181 RM-182 RM-183 In a preferred embodiment, the mixture according to the invention comprises one or more polymerizable compounds, preferably selected from polymerizable compounds of the formulas RM-1 to RM-182. Among them, 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-58, RM-64, RM-74, RM-76, RM-88, RM-91, RM-102, RM-103, RM-109, RM-116, RM -117, RM-120, RM-121, RM-122, RM-139, RM-140, RM-142, RM-143, RM-145, RM-146, RM-147, RM-149, RM-156 RM-163 to RM-169, RM-170 and RM-171 to RM-183 are particularly preferred.

Table E Table E shows self-aligning additives for vertical alignment that can be used together with polymerizable compounds of formula M in the LC media of SA-VA and SA-FFS displays according to the invention: SA-1 SA-2 SA-3 SA-4 SA-5 SA-6 SA-7 SA-8 SA-9 SA-10 SA-11 SA-12 SA-13 SA-14 SA-15 SA-16 SA-17 SA-18 SA-19 SA-20 SA-21 SA-22 SA-23 SA-24 SA-25 SA-26 SA-27 SA-28 SA-29 SA-30 SA-31 SA-32 SA-33 SA-34 SA-35 SA-36 SA-37 SA-38 SA-39 SA-40 SA-41 SA-42 SA-43 SA-44 SA-45 SA-46 SA-47 SA-48 In a preferred embodiment, the LC media, SA-VA and SA-FFS displays according to the invention comprise one or more of the formulas SA-1 to SA-48, preferably of the formulas SA-14 to SA-48, very Preference is given to SA additives selected from formulas SA-20 to SA-34 and SA-44, in combination with one or more RMs of formula M.

Example

The following examples illustrate the invention without limiting it. However, they show the person skilled in the art the concept of preferred mixtures with the compounds preferably used and their corresponding concentrations as well as their combinations with one another. Furthermore, these examples illustrate which properties and combinations of properties are achievable.

In addition, the following abbreviations and symbols are used, V ₀ threshold voltage at 20°C, _capacitive [V], ne extraordinary refractive index at 20°C and 589 nm, _no ordinary refractive index at 20°C and 589 nm , Δn Optical anisotropy at 20°C and 589 nm, ε _⊥ Permittivity perpendicular to the director at 20°C and 1 kHz, ε _|| Dielectric constant parallel to the director at 20°C and 1 kHz Electrical constant, Δε Dielectric anisotropy at 20°C and 1 kHz, cl.p., T(N,I) clearing point [°C], Rotational viscosity of _γ1 at 20°C [mPa·s] , K ₁ elastic constant, "splay" deformation at 20°C [pN], K ₂ elastic constant, "twist" deformation at 20°C [pN], K ₃ elastic constant, "bending" deformation at 20°C "Transformation [pN], and unless expressly stated otherwise, all concentrations in this application are expressed in percent by weight and relative to the corresponding entire mixture, including all solid or liquid crystalline components, excluding solvents.

Unless expressly stated otherwise, in this application are indicated, for example, for melting point T(C,N), transition from smectic (S) to nematic (N) phase T(S,N) and clearing point T(N,I) All temperature values for , are expressed in degrees Celsius (°C). M.p. means melting point, cl.p. = clearing point. Also, C = crystalline, N = nematic, S = smectic, and I = isotropic. The data between these symbols represent the transition temperature.

Unless expressly stated otherwise, all physical properties are determined according to "Merck Liquids Crystal, Physical Properties of Liquid Crystals", Status Nov. 1997, Merck KGaA, Germany, and apply for a temperature of 20°C with Δn at 589 nm and Δε at 1 Measured at kHz.

Unless expressly stated otherwise, the term "threshold voltage" in the present invention relates to the capacitive threshold (V ₀ ), also known as the Freedericks threshold. In an embodiment, the optical threshold may also be expressed as 10% relative contrast (V ₁₀ ) as commonly used.

Unless otherwise stated, the methods of preparing the test cartridges and measuring their electro-optical and other properties were carried out by the methods described below or analogous thereto.

Displays for measuring capacitive threshold voltage typically consist of two plane-parallel glass outer plates, each with an electrode layer on the inside and an unrubbed polyimide alignment layer on top, which affects the required Edge alignment of liquid crystal molecules.

Example 1 Prepare the nematic LC mixture N1 as follows B(S)-2O-O4 3.00 % cl.p. 82.7°C B(S)-2O-O5 4.00 % Δn 0.0928 B(S)-2O-O6 2.00 % n _e 1.5742 CC-3-V 45.00 % _no 1.4814 CC-3-V1 6.00 % Δε -3.1 CCY-3-O2 8.00 % ε _|| 3.5 CLY-3-O2 8.00 % ε _⊥ 6.6 CLY-3-O3 7.00 % | ₁ 82 ^mPa.s CLY-4-O2 5.00 % K ₁ 15.6 CPY-3-O2 5.00 % K ₃ 16.1 PY-2-3 2.00 % K ₃ /K ₁ 1.03 Y-4O-O4 4.00 % V ₀ 2.42V CCP-2F.FF 1.00 % LC mixture N1 contained 1% of the compound of formula C CCP-2F.FF and showed good reliability and low image sticking.

Example 2 Prepare the nematic LC mixture N2 as follows B(S)-2O-O4 3.00 % cl.p. 82.5°C B(S)-2O-O5 4.00 % Δn 0.0928 B(S)-2O-O6 2.00 % n _e 1.5743 CC-3-V 45.00 % _no 1.4815 CC-3-V1 4.00 % Δε -2.9 CCY-3-O2 8.00 % ε _|| 3.8 CLY-3-O2 8.00 % ε _⊥ 6.7 CLY-3-O3 7.00 % | ₁ 82 ^mPa.s CLY-4-O2 5.00 % K ₁ 15.4 CPY-3-O2 5.00 % K ₃ 15.7 PY-2-3 2.00 % K ₃ /K ₁ 1.02 Y-4O-O4 4.00 % V ₀ 2.47V CCP-2F.FF 3.00 % LC mixture N2 contained 3% of the compound of formula C CCP-2F.FF and showed good reliability and low image sticking.

Example 3 Prepare the nematic LC mixture N3 as follows B(S)-2O-O4 3.00 % cl.p. 81.9°C B(S)-2O-O5 4.00 % Δn 0.0926 B(S)-2O-O6 2.00 % n _e 1.5737 CC-3-V 43.00 % _no 1.4811 CC-3-V1 1.50 % Δε -2.8 CCY-3-O2 8.50 % ε _|| 4.3 CLY-3-O2 8.00 % ε _⊥ 7.1 CLY-3-O3 7.50 % | ₁ 86 ^mPa.s CLY-4-O2 5.00 % K ₁ 15.0 CPY-3-O2 5.50 % K ₃ 15.0 PY-2-3 1.00 % K ₃ /K ₁ 1.00 Y-4O-O4 5.00 % V ₀ 2.45V CCP-2F.FF 6.00 % LC mixture N3 contained 6% of the compound of formula C CCP-2F.FF and showed good reliability and low image sticking.

Example 4 Prepare the nematic LC mixture N4 as follows B(S)-2O-O5 4.00 % cl.p. 91.1°C CC-3-V 34.00 % Δn 0.0903 CC-3-V1 7.50 % n _e 1.5689 CCY-3-O1 4.50 % _no 1.4786 CCY-3-O2 8.00 % Δε -3.3 CLY-2-O4 5.00 % ε _|| 3.7 CLY-3-O2 9.00 % ε _⊥ 7.0 CLY-3-O3 8.00 % CLY-4-O2 5.00 % CLY-5-O2 5.00 % PYP-2-3 2.00 % Y-4O-O4 6.00 % CCP-2F.FF 2.00 %

Example 5 Prepare the nematic LC mixture N5 as follows B(S)-5cy1O-O2 3.00 % cl.p. 82.0°C B(S)-2O-O5 4.00 % Δn 0.0925 B(S)-2O-O6 2.00 % Δε -3.0 CC-3-V 45.00 % ε _|| 3.5 CC-3-V1 4.00 % ε _⊥ 6.5 CCY-3-O2 8.00 % | ₁ 84 mPa.s CLY-3-O2 8.00 % CLY-3-O3 7.00 % CLY-4-O2 5.00 % CPY-3-O2 5.00 % PY-2-3 2.00 % Y-4O-O4 4.00 % CCP-2F.FF 3.00 %

Example 6 Prepare the nematic LC mixture N6 as follows B(S)-2O-O4 3.00 % cl.p. 81.0°C B(S)-3cy1O-O4 4.00 % Δn 0.0925 B(S)-2O-O6 2.00 % Δε -2.9 CC-3-V 45.00 % ε _|| 3.5 CC-3-V1 4.00 % ε _⊥ 6.4 CCY-3-O2 8.00 % | ₁ 85 mPa.s CLY-3-O2 8.00 % CLY-3-O3 7.00 % CLY-4-O2 5.00 % CPY-3-O2 5.00 % PY-2-3 2.00 % Y-4O-O4 4.00 % CCP-2F.FF 3.00 %

Example 7 Prepare the nematic LC mixture N7 as follows B(S)-2O-O5 4.00 % cl.p. 90.5°C CC-3-V 34.00 % Δn 0.0901 CC-3-V1 7.50 % Δε -3.2 CCY-3-O1 4.50 % ε _|| 3.7 CCY-3-O2 8.00 % ε _⊥ 6.9 CLY-2-O4 5.00 % CLY-5cy-O2 9.00 % CLY-3-O3 8.00 % CLY-4-O2 5.00 % CLY-5-O2 5.00 % PYP-2-3 2.00 % Y-4O-O4 6.00 % CCP-2F.FF 2.00 %

Example 8 Prepare the nematic LC mixture N8 as follows B(S)-2O-O4 3.00 % cl.p. 81.5°C B(S)-4cy1O-O2 4.00 % Δn 0.0925 B(S)-2O-O6 2.00 % Δε -3.0 CC-3-V 45.00 % ε _|| 3.5 CC-3-V1 4.00 % ε _⊥ 6.5 CCY-3-O2 8.00 % | ₁ 85 mPa.s CLY-3-O2 8.00 % CLY-3-O3 7.00 % CLY-4-O2 5.00 % CPY-3-O2 5.00 % PY-2-3 2.00 % Y-4O-O4 4.00 % CCP-3F.FF 3.00 %

Example 9 Prepare the nematic LC mixture N9 as follows B(S)-2O-O5 4.00 % cl.p. 91.1°C CC-3-V 34.00 % Δn 0.0903 CC-3-V1 7.50 % n _e 1.5689 CCY-3-O1 4.50 % _no 1.4786 CCY-3-O2 8.00 % Δε -3.3 CLY-2-O4 5.00 % ε _|| 3.7 CLY-3-O2 9.00 % ε _⊥ 7.0 CLY-3-O3 8.00 % CLY-4-O2 5.00 % CLY-5-O2 5.00 % PYP-2-3 2.00 % Y-4O-O4 6.00 % CCP-3F.FF 2.00 %

Example 10 To the nematic mixture N1 in Example 1, 150 ppm of stabilizer S1-1 was added. S1-1

Example 11 To the nematic mixture N4 in Example 4, 300 ppm of stabilizer S1-1, 100 ppm of stabilizer S3-2 and 100 ppm of stabilizer S3-3 were added. S3-2 S3-3

Example 12 To the nematic mixture N4 in Example 4, 300 ppm of stabilizer S1-1, 50 ppm of stabilizer S3-1 and 100 ppm of stabilizer S3-3 were added.

Example 13 To the nematic mixture N1 in Example 1, 150 ppm of stabilizer S1-1 and 0.3% of compound RM-1 were added. RM-1

Example 14 To the nematic mixture N1 in Example 1, 150 ppm of stabilizer S2-1 and 0.3% of compound RM-35 were added. S2-1 RM-35

Example 15 To the nematic mixture N2 in Example 2, 200 ppm of stabilizer S3-1 and 0.3% of compound RM-64 were added. S3-1 RM-64

Example 16 To the nematic mixture N4 in Example 4, 200 ppm of stabilizer S1-1 and 0.3% of compound RM-120 were added. RM-120

Example 17 To the nematic mixture N4 in Example 4, 200 ppm of stabilizer S2-1 and 0.3% of compound RM-171 were added. RM-171

Example 18 To the nematic mixture N1 in Example 1, 150 ppm of stabilizer S1-1, 0.3% of compound RM-1 and 0.3% of compound RM-171 were added.

Example 19 To the nematic mixture N4 in Example 4, 150 ppm of stabilizer S1-1, 0.3% of compound RM-1 and 0.2% of compound RM-143 were added. RM-143

Example 20 To the nematic mixture N4 in Example 4, 150 ppm of stabilizer S2-1, 0.3% of compound RM-1 and 0.1% of compound RM-143 were added.

Claims (17)

A liquid crystal (LC) medium having negative dielectric anisotropy and comprising one or more compounds of formula C: C wherein the individual groups are independent of each other and have the same or different meanings at each occurrence: ^R is a linear, branched or cyclic alkyl group having 1 to 25 C atoms, one or more of which are not adjacent The CH ₂ -group is optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, CR ⁰ =CR ⁰⁰ -, - C≡C-, , , , , or Substituted in such a way that the O- and/or S-atoms are not directly connected to each other, and wherein one or more H atoms are each optionally replaced by F or Cl, preferably an alkyl or alkoxy group having 1 to 6 C atoms group, L ¹ and L ² are F, Cl, OCF ₃ , CF ₃ , CH ₃ , CH ₂ F or CHF ₂ , preferably F or Cl, very preferably F. The LC medium as claimed in item 1 is characterized in that it comprises one or more compounds of formula C selected from the following formulae: C1 wherein R ¹ has one of the meanings given in claim 1. The LC medium according to claim 1 or 2, characterized in that it comprises one or more compounds of formula C or C1, wherein ^R1 is ethyl, n-propyl or n-butyl. LC medium according to any one of claims 1 to 3, characterized in that the proportion of the compound of the formula C or C1 is >0 to ≤5% by weight. LC medium according to any one of claims 1 to 4, characterized in that it additionally comprises one or more compounds of formula III: III wherein R ¹¹ and R ¹² each independently represent H, an alkyl or alkoxy group having 1 to 15 C atoms, wherein one or more _CH groups in these groups may each independently be represented by , , , , , -C≡C-, -CF ₂ O-, -OCF ₂ -, -CH=CH-, by -O-, -CO-O- or -O-CO-in such a way that the O atoms are not directly connected to each other instead, and wherein in addition, one or more H atoms may be replaced by a halogen, L ¹¹ and L ¹² each independently of each other represent F, Cl, CF ₃ or CHF ₂ , A ³ , in each occurrence, independently of each other represents a ) 1,4-cyclohexenyl or 1,4-cyclohexylene, wherein one or two non-adjacent CH ₂ groups may be replaced by -O- or -S-, b) 1,4-extended Phenyl, where one or both CH groups may be replaced by N, or c) selected from spiro[3.3]heptane-2,6-diyl, 1,4-bicyclo[2.2.2]octyl, naphthalene -2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl and fluorene-2 , a 7-diyl radical, wherein the radicals a), b) and c) can be mono- or polysubstituted by halogen atoms, n represents 0, 1 or 2, preferably 0 or 1, Z ¹ each occurrence is relative to the other independently represent -CO-O-, -O-CO-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -CH ₂ -, -CH ₂ CH ₂ -, - (CH ₂ ) ₄ -, -CH=CH-CH ₂ O-, -C ₂ F ₄ -, -CH ₂ CF ₂ -, -CF ₂ CH ₂ -, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C- or a single bond, and W represents O or S. LC medium according to any one of claims 1 to 5, characterized in that it comprises one or more compounds of formula III-1 and/or III-2: III-1 III-2 The groups appearing therein have the same meanings as given in Claim 5, and preferably R ^{and R} are each independently of each other an alkyl, alkenyl or alkoxy group having at most 15 C atoms, and L ^and L ¹² each represent F. LC medium as any one of claims 1 to 6, characterized in that it also comprises one or more compounds of formula II: II wherein each group is independent of each other and has the same or different ^meanings at each occurrence: R and ^R are linear, branched or cyclic alkyl groups having 1 to 25 C atoms, one or more of which Nonadjacent _CH2 -groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, CR ⁰ =CR ⁰⁰ -, -C≡C-, , , , , or Substituted in such a way that the O- and/or S-atoms are not directly connected to each other, and wherein one or more H atoms are each optionally replaced by F or Cl, A ^{and A} are groups selected from the following formulae: A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13 A14 A15 A16 wherein each group is independent of each other and has the same or different meanings at each occurrence: Z ¹ and Z ² are -CH ₂ CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -CO-O-, -O-CO-, -C ₂ F ₄ -, -CF=CF-, -CH=CH-CH ₂ O- or a single bond, L ¹ , L ² , L ³ and L ⁴ are F, Cl, OCF ₃ , CF ₃ , CH ₃ , CH ₂ F or CHF ₂ , preferably F or Cl, Y is H, F, Cl, CF ₃ , CHF ₂ or CH ₃ , preferably H or CH ₃ , ^LC is CH ₃ or OCH ₃ , a1 is 1 or 2, and a2 is 0 or 1. The LC medium according to any one of claims 1 to 7, characterized in that it comprises one or more compounds of formula II selected from the group consisting of compounds of formula IIA, IIB, IIC and IID: IIA IIB IIC IID wherein each of R ^2A and R ^2B independently of each other represents H, an alkyl or alkenyl group having up to 15 C atoms, which is unsubstituted, monosubstituted by CN or CF ₃ or at least monosubstituted by halogen, wherein in addition, these One or more _CH2 groups in the group can be replaced by -O-, -S-, , , , , , -C≡C-, -CF ₂ O-, -OCF ₂ -, -OC-O-, or -O-CO- are substituted in such a way that the O atoms are not directly connected to each other, L ¹ to L ⁴ are each independently of each other represents F, Cl, CF ₃ or CHF ₂ , Y represents H, F, Cl, CF ₃ , CHF ₂ or CH ₃ , Z ² , Z ^2B and Z ^2D each independently represent a single bond, -CH ₂ CH ₂ - , -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO-, -C ₂ F ₄ -, -CF=CF-, -CH=CHCH ₂ O-, p represents 0, 1 or 2, and q represents 0 or 1 identically or differently at each occurrence. LC medium according to any one of claims 1 to 8, characterized in that it comprises one or more compounds of formula IIC-1: IIC-1 wherein alkyl and alkyl ^* each independently represent a straight-chain alkyl group having 1 to 6 C atoms. LC medium as any one of claims 1 to 9, characterized in that it comprises one or more compounds of formula IID-4: IID-4 wherein alkyl and alkyl ^* each independently represent a straight-chain alkyl group having 1 to 6 C atoms. LC medium according to any one of claims 1 to 10, characterized in that it additionally comprises one or more compounds of formula IV: IV wherein R ⁴¹ represents an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkenyl group having 2 to 7 C atoms, and R ⁴² represents an unsubstituted alkyl group having 1 to 7 C atoms or Unsubstituted alkoxy having 1 to 6 C atoms, or unsubstituted alkenyl having 2 to 7 C atoms. The LC medium according to any one of claims 1 to 11, further comprising one or more compounds of formula IIA-Y6a: IIA-Y6a wherein Alkoxy and Alkoxy ^* independently represent straight-chain alkoxy groups having 1-6 C atoms. LC medium according to any one of claims 1 to 12, characterized in that it further comprises one or more polymerizable compounds. The LC medium according to any one of claims 1 to 13, characterized in that it further comprises one or more additives selected from stabilizers, chiral dopants, polymerization initiators and self-alignment additives. A method for preparing an LC medium as any one of claim items 1 to 14, comprising one or more compounds of formula C or C1 as defined in any one of claim items 1 to 3 and one or more compounds such as claim item 5 Compounds of formula II, III, IV and/or V as defined in any one of claims 12, optionally mixed with one or more polymerizable compounds and/or additives as defined in claims 13 or 14, and optionally A step of mixing with other liquid crystal compounds and/or additives as needed. An LC display comprising the LC medium as defined in any one of claims 1 to 14. As the LC display of claim 16, it is a VA, SA-VA, IPS, PS-IPS, FFS, PS-FFS, UB-FFS or PS-UB-FFS display.