WO2010057575A1

WO2010057575A1 - Liquid crystalline medium

Info

Publication number: WO2010057575A1
Application number: PCT/EP2009/007875
Authority: WO
Inventors: Georg Bernatz; Melanie Klasen-Memmer; Matthias Bremer; Sabine Schoen
Original assignee: Merck Patent Gmbh
Priority date: 2008-11-19
Filing date: 2009-11-03
Publication date: 2010-05-27
Also published as: JP6370527B2; JP2012509369A; DE112009002315A5

Abstract

The invention relates to a dielectrically negative, liquid crystalline medium that comprises a) a first dielectrically negative component (Component A) made of one or more dielectrically negative bonds of the formula (I) and b) a second dielectrically negative component (Component B) made of one or more dielectrically negative bond(s) of the formula (II), wherein the parameters have the respective meanings in Claim 1, use of said medium in an electro-optical display, particularly in an active matrix display based on the VA, ECB, PALC, FFS or IPS effect and similar displays.

Description

Liquid crystalline medium

The present invention relates to liquid crystal media and their use in liquid crystal displays, as well as these liquid crystal displays, especially liquid crystal displays, which use the ECB (Electrically Controlled

Birefringence) effect with dielectrically negative liquid crystals in a homeotropic starting orientation. The liquid-crystal media according to the invention are distinguished by a particularly low switching time in the displays according to the invention with a simultaneously high voltage holding ratio.

Ads using the ECB effect have become known as VAN (Vertically Aligned Nematic) ads in addition to IPS (In Plane Switching) ads (eg: Yeo, SD, Lecture 15.3: "A LC Display for the TV Application"). SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp. 758 & 759) and the long-known TN (Twisted Nematic) displays, being established as one of the three currently most important new types of carbon black displays, particularly for television broadcasting.

The most important types are: MVA (Multi-Domain Vertical Alignment, eg: Yoshide, H. et al., Lecture 3.1: "MVA LCD for Notebook or Mobile PCs ...", SlD 2004 International Symposium, Digest of Technical Papers, XXXV, Book I, pp. 6-9 and Liu, CT et al., Lecture 15.1: "A 46-inch TFT-LCD HDTV Technology ...", SID 2004 International Symposium, Digest of Technical Papers , XXXV, Book II, pp. 750-753), PVA (Patterned Vertical Alignment, eg: Kim, Sang Soo, Lecture 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. 760-763) and ASV (Avanced Super View, eg: Shigeta, Mitzuhiro and Fukuoka, Hirofumi, Lecture 15.2: "Development of High Quality LCDTV ", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp. 754-757).

in general terms, the technologies will be used eg 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, lan, SID Seminar 2004, Seminar M-7: "LCD Television", Seminar Lecture Notes, M-7/1 to M-7/32 Although the switching times of modern ECB displays have already been significantly improved by overdrive control methods, for example: Kim, Hyeon Kyeong et al., Lecture 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, the achievement of video-capable switching times, especially when switching grayscale, is still an unsatisfactorily solved problem ,

Like ASV displays, ECB displays use liquid-crystalline media with negative dielectric anisotropy (Δε), whereas TN and hitherto all common IPS displays use liquid-crystalline media with positive dielectric anisotropy.

In such liquid crystal displays, the liquid crystals are used as dielectrics whose optical properties reversibly change upon application of an electric voltage.

Since in displays in general, including ads for these effects mentioned, the operating voltage should be as low as possible, liquid crystal media are used, which are usually composed predominantly of liquid crystal compounds, all of which have the same sign of dielectric anisotropy and the largest possible amount have the dielectric anisotropy. As a rule, at most lower proportions of neutral compounds and as far as possible no compounds with a sign of the dielectric anisotropy, which is opposite to that of the medium, are used. In the case of the liquid-crystal media with negative dielectric anisotropy for ECB displays, predominantly compounds with negative dielectric anisotropy are used. As a rule, the liquid-crystal media used predominantly and mostly even consist largely of liquid-crystal compounds with negative dielectric anisotropy. In the media used according to the present application are typically at most significant amounts of dielectrically neutral liquid crystal compounds and usually only very small amounts of or no dielectrically positive compounds used, since generally the liquid crystal displays should have the lowest possible drive voltages.

The liquid crystal media of the prior art with correspondingly low drive voltages have relatively low electrical resistances or a low voltage holding ratio and often result in undesirable "flicker" and / or insufficient transmission in the displays.

In addition, the drive voltage of the displays of the prior art is often too large, especially for displays that are not connected directly or not continuously to the power grid such. B. Ads for mobile applications.

In addition, the phase range must be sufficiently wide for the intended application.

In particular, the switching times of the liquid-crystal media in the displays must be improved, ie reduced. This is especially important for ads for television or multi-media applications. To improve the switching times, it has repeatedly been proposed in the past to optimize the rotational viscosity of the liquid-crystal media (γ-i), ie to realize media with the lowest possible rotational viscosity. However, the results obtained are not sufficient for many applications and therefore make it desirable to find further optimization approaches.

Thus, there is a great need for liquid-crystal media which does not have the disadvantages of the prior art media, or at least to a much lesser extent. Surprisingly, it has been found that liquid crystal displays can be realized which have a short switching time in ECB displays and at the same time have a sufficiently broad nematic phase, a favorable birefringence (Δn) and a high voltage holding ratio. Such media are especially for electro-optical displays with a

Use active matrix addressing based on the ECB effect as well as for in-plane switching IPS. The medium according to the invention preferably has a negative dielectric anisotropy.

The principle of electrically controlled birefringence, the ECB effect (electrically controlled birefringence) or the DAP effect (deformation of upright phases) was first described in 1971 (MF Schieckel and K. Fahrenschon, "Deformation of nematic liquid crystals with vertical orientation in electrical fields Phys. Lett 19 (1971), 3912). Works by J.F. Kahn (Appl Phys Lett 20 (1972), 1193) and G. Labrunie and J. Robert (J. Appl. Phys. 44 (1973), 4869) followed.

The work of 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) have shown that liquid crystalline phases must have high values for the ratio of the elastic constants K ^ K ₁ , high values for the optical anisotropy Δn and values for the dielectric anisotropy Δε <-0.5 in order to obtain highly informative display elements based on the ECB effect can be used. Electro-optical display elements based on the ECB effect have a homeotropic edge orientation (VA technology = Vertical Aligned). Even displays that use the so-called IPS effect, dielectric-negative liquid-crystal media can be used.

For the technical application of this effect in electro-optical display elements FK phases are needed, which must meet a variety of requirements. Particularly important here are the chemical resistance to moisture, air and physical influences such as heat, radiation in the infrared, visible and ultraviolet range and electrical alternating and alternating fields. Furthermore, technically usable LC phases require a liquid-crystalline mesophase in a suitable temperature range and a low viscosity.

In none of the previously known series of compounds with liquid-crystalline mesophase there is a single compound that meets all these requirements. As a rule, mixtures of two to 25, preferably three to 18, compounds are therefore prepared in order to obtain substances which can be used as FK phases.

Matrix liquid crystal displays (MFK displays) are known. For example, active elements (i.e., transistors) may be used as non-linear elements for individual switching of the individual pixels. This is referred to as an "active matrix", generally using thin-film transistors (TFT), which are usually arranged on a glass plate as a substrate.

A distinction is made between two technologies: TFTs of compound semiconductors, such as e.g. CdSe or TFTs based on polycrystalline and u.a. amorphous silicon. The latter technology currently has the greatest commercial significance worldwide.

The TFT matrix is applied on the inside of one glass plate of the display, while the other glass plate on the inside carries the transparent counterelectrode. Compared to the size of the pixel electrode, the TFT is very small and practically does not disturb the image. This technology can also be extended for fully color-capable image representations, wherein a mosaic of red, green and blue filters is arranged in such a way that one filter element each lies opposite a switchable image element.

The most commonly used TFT displays commonly use crossed polarity in transmission and are backlit. For TV applications, IPS cells or ECB (or VAN) cells are used, whereas for monitors, mostly IPS cells or TNB cells are used. Cells and for notebooks, lap tops and for mobile applications mostly TN cells.

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

Such MFK displays are particularly suitable for TV applications, monitors and "note books" or for displays with high information density, for example in the automobile or aircraft industry.For problems with the angular dependence of the contrast and the switching times resulting in MFK displays difficulties due to a insufficiently high resistivity of the liquid-crystal mixtures [TOGASHI, S., SEKIGUCHI, K., TANABE, H., YAMAMOTO ₁ E., SORIMACHI, K.,

TAJIMA, E., WATANABE, H., SHIMIZU, H., Proc. Eurodisplay 84, Sept. 1984: A 210-288 Matrix LCD Controlled by Double Stage Diode Rings, p. 141 ff, Paris; STROMER, M., Proc. Eurodisplay 84, Sept. 1984: Design of Thin Film Transistors for Matrix Liquid Crystal Displays, p. 145 ff, Paris]. As the resistance decreases, the contrast of a MFK display degrades. Since the resistivity of the liquid crystal mixture generally decreases over the life of an MFK display due to interaction with the internal surfaces of the display, high (initial) resistance is very important for displays that must have acceptable resistance values over a long period of operation.

Compounds of the formula I are used in combination with virtually dielectrically neutral indanes as components of liquid-crystal mixtures, for example in JP 2005-047 980 A. There, reference is also made to the preparation of the compounds of the formula I. Compounds of the formula I are mentioned in combination with indanes with negative dielectric anisotropy in the not yet disclosed patent application DE 10 2008 01 46 49.8. Compounds of the formula II are known, for example, from EP 0 364 538, EP 0363 548 and DE 39 06 058. There are also described the syntheses of some such compounds. Other compounds of the formula II are prepared analogously.

The disadvantage of the previously known MFK displays is based on their comparatively low contrast, the relatively high viewing angle dependency and the difficulty in these displays grayscale, and their insufficient voltage holding ratio and their insufficient life.

Thus, there is still a great need for MFK displays with very high resistivity combined with a large operating temperature range, short switching times and low threshold voltage, which can be used to generate different gray levels and in particular have a good and stable voltage holding ratio.

The invention has for its object MFK displays, not only for monitor and TV applications, but also for mobile phones and navigation systems, which are based on the ECB or on the IPS effect to provide the above-mentioned disadvantages or only to a lesser extent and at the same time have very high resistivities. In particular, it must be ensured for mobile phones and navigation systems that they work even at extremely high and extremely low temperatures.

Surprisingly, it has now been found that this object can be achieved by using nematic liquid-crystal mixtures containing at least one compound of the formula I and at least one compound of the formula II in these display elements.

The invention thus relates to a liquid-crystalline medium based on a mixture of polar compounds which contains at least one compound of the formula I and at least one compound of the formula II. The mixtures according to the invention exhibit very broad nematic phase ranges with clearing points> 85 ⁰ C, very favorable values for the capacitive threshold, relatively high values for the holding ratio and at the same time very good low-temperature stabilities at -30 ⁰ C and -40 ⁰ C as well as very low rotational viscosities. Furthermore, the mixtures according to the invention are distinguished by a good ratio of clearing point and rotational viscosity and by a high negative dielectric anisotropy.

The invention relates to a dielectric negative, nematic medium which

a) a first dielectric negative component (component A), which preferably consists of one or more compounds of the formula I.

wherein

R ¹¹ and R ^{12 are} each, independently of one another, H, an unsubstituted alkyl or alkenyl radical having up to 15 C atoms, where in these radicals also one or more CH ₂ groups is represented by -O-, -S-, - <0> - -C≡C-, -CF ₂ -O-, -O-CF ₂ -,

-CO-O- or -O-CO- may be replaced so that O atoms are not directly linked to one another, preferably an unsubstituted alkyl, alkenyl, alkoxy or alkenyloxy radical, particularly preferably one of R ¹¹ and R ¹² Alkyl or alkenyl radical and the other an alkyl, alkenyl, alkoxy or alkenyloxy radical, particularly preferably R ¹¹ straight-chain alkyl or alkenyl, in particular CH ₂ = CH-, E-CH ₃ -CH = CH-, CH ₂ = CH- CH ₂ -CH ₂ -, CH ₃ -CH = CHC ₂ H ₄ -, CH ₃ -, C ₂ Hs-, HC ₃ H ₇ , / 7-C ₄ H ₉ - or HC ₅ H ₁₁ - and R i12 alkoxy, in particular C ₂ H ₅ -O- or HC ₄ H ₉ -O-, one of the rings present

to

and the others, if any, each independently

or preferred

or more preferably

very particularly preferred

and especially preferred

Z ¹¹ to Z ^{13 are} each independently of one another -CH ₂ -CH ₂ -, -CH = CH- -C≡C-, -CH ₂ -O-, -O-CH ₂ -, -CO-O-, -O-CO-, -CF ₂ -O-, -O-CF ₂ -, -CF ₂ - CF ₂ - or a single bond, preferably -CH ₂ -CH ₂ -, -CH = CH-, -C≡C-, -CF ₂ -O-, -O-CF ₂ - or a single bond, particularly preferably one or, if present, a plurality of Z ¹¹ to Z ¹³ and most preferably Z ¹¹ to Z ¹³ all a single bond,

m and n are each independently 0 or 1 and

(m + n) preferably 0 or 1, particularly preferably 0,

mean,

b) a second dielectric negative component (component B), which consists of one or more compounds of formula II

wherein

R ²¹ and R ^{22 are} each, independently of one another, H, an unsubstituted alkyl or alkenyl radical having up to 15 C atoms, where in these radicals also one or more CH ₂ groups is represented by -O-, -S-,

, -C≡C-, -CF ₂ -O-, -O-CF ₂ -,

-CO-O- or -O-CO- can be replaced so that O atoms are not directly linked to each other, preferably an unsubstituted alkyl, alkenyl, alkoxy or alkenyloxy, particularly preferably one of R ²¹ and R ²² a Alkyl or alkenyl radical and the other an alkyl, alkenyl, alkoxy or Alkenyloxyrest, preferably independently of one another alkyl having 1 to 7 C-atoms, preferably n-alkyl, particularly preferably n-alkyl having 1 to 5 C-atoms, alkoxy with 1 to 7 C atoms, preferably n- Alkoxy, particularly preferably n-alkoxy having 1 to 5 carbon atoms or alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7 carbon atoms, preferably having 2 to 4 carbon atoms, preferably alkenyl, wherein in all groups one or more HI atoms can be replaced by halogen atoms, preferably F atoms,

particularly preferably one of R ²¹ and R ²² , preferably R ²¹ , an alkyl or alkenyl radical and the other an alkyl, alkenyl, alkoxy or Alkenyloxyrest, more preferably R ²¹ straight-chain alkyl, in particular CH ₃ -, C ₂ H ₅ -, HC ₃ H ₇ , HC ₄ H ₉ - or HC ₅ Hn-, or alkenyl, especially CH ₂ = CH-, E-CH ₃ -CH = CH-, CH ₂ = CH-CH ₂ -CH ₂ -, E-CH ₃ -CH = CH-CH ₂ -CH ₂ - or EHC ₃ H ₇ -CH = CH-,

one of the existing rings

preferably at least one of

and

particularly preferred

and the others, if any, each independently

L ²¹ and L ²² independently = C (X ² ) - and one of L ²¹ and L ²² alternatively also = N-, wherein preferably at least one of L ²¹ and L ²² = C (-F) - and the other = C (-F) - or = C (-CI) -, more preferably L ²¹ and L ²² both = C (-F) -,

F, Cl, OCF ₃ , CF ₃ , CH ₃ , CH ₂ F, CHF ₂ , preferably F or Cl, particularly preferably F,

particularly preferred

particularly preferred

and most preferably

Z ²¹ to Z ^{23 are} each independently -CH ₂ -CH ₂ -, -CH ₂ -CF ₂ -, -CF ₂ -CH ₂ -, -CF ₂ -CF ₂ -, - CH = CH-, -CF = CH -, - CH = CF-, -C≡C-, -CH ₂ -O-, -O-CH ₂ -, -O-, -CH ₂ -, -CO-O-, -O-CO-, - CF ₂ -O-, -O-CF ₂ - or a single bond, preferably -CH ₂ -CH ₂ -, -CH = CH-, -C≡C-, -CF ₂ -O-, -O-CF ₂ - or a single bond, more preferably one or, if present, more of Z ²¹ to Z ²³ a single bond, and most preferably all a single bond,

and o are each independently 0 or 1 and

(I ⁺ O) preferably 0 or 1

mean and if necessary

c) a dielectrically neutral component (component C) consisting of one or more compounds of formula III

wherein

R ³¹ and R ^{32 are} each independently of one another, have one of the meaning given for R ¹¹ and R ¹² and preferably alkyl with 1 to 7 carbon atoms, preferably n-alkyl, particularly preferably n-alkyl having 1 to 5 carbon atoms, alkoxy having 1 to 7 carbon atoms, preferably n-alkoxy, particularly preferably π-alkoxy having 2 to 5 carbon atoms , Alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7 C atoms, preferably having 2 to 4 C atoms, preferably alkenyloxy,

each independently

prefers

prefers

and, if present, preferred

Each of Z ³¹ to Z 33 independently of one another has one of the meanings given for Z ¹¹ to Z ¹³ and preferably -CH ₂ -CH ₂ -, -CH = CH-, -C≡C-, -COO- or a single bond, preferably -CH ₂ -CH ₂ - or a single bond, and more preferably a single bond,

p and q are each independently, 0 or 1,

(P ⁺ q) preferably 0 or 1, preferably 0,

mean and if necessary d) another dielectrically negative component {component D) consisting of one or more compounds selected from the group of the compounds of the formulas IV and V.

wherein

R ⁴¹ and R ⁴² , R ⁵¹ and R ^{52 are} each, independently of one another, H, an unsubstituted alkyl or alkenyl radical having up to 15 C atoms, where in these radicals also one or more CH ₂ groups are substituted by -O-, -S- .

, -C≡C-, -CF ₂ -O-,

-O-CF ₂ -, -CO-O- or -O-CO- can be replaced so that O atoms are not directly linked, preferably an unsubstituted alkyl, alkenyl, alkoxy or Alkenyloxyrest, more preferably one R ²¹ and R ^{22 is} an alkyl or alkenyl radical and the other is an alkyl, alkenyl, alkoxy or Alkenyloxyrest, preferably independently of one another alkyl having 1 to 7 carbon atoms, preferably n-alkyl, particularly preferably π-alkyl with 1 to 5 carbon atoms, alkoxy having 1 to 7 carbon atoms, preferably n-alkoxy, particularly preferably / i-alkoxy having 1 to 5 carbon atoms or alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7 carbon atoms, preferably 2 up to 4 C atoms, preferably alkenyl, where in all groups one or more H atoms can be replaced by halogen atoms, preferably F atoms,

particularly preferably one of R ⁴¹ and R ⁴² , preferably R ⁴¹ , an alkyl or alkenyl radical and the other an alkyl, Alkenyl, alkoxy or Alkenyloxyrest, particularly preferably R ²¹ straight-chain alkyl, in particular CH ₃ -, C ₂ H ₅ -, HC ₃ H ₇ , HC ₄ H ₉ - or / 7-C ₅ Hn-, or alkenyl, in particular CH ₂ = CH-, E-CH ₃ -CH = CH-, CH ₂ = CH-CH ₂ -CH ₂ -, E-CH ₃ -CH = CH-CH ₂ -CH ₂ - or EHC ₃ H ₇ -CH = CH-,

particularly preferably one of R ⁵¹ and R ⁵² , preferably R ⁵¹ , an alkyl or alkenyl radical and the other an alkyl, alkenyl, alkoxy or Alkenyloxyrest, particularly preferably R ⁴¹ straight-chain alkyl, in particular CH ₃ -, C ₂ H ₅ -, HC ₃ H ₇ , HC ₄ H ₉ - or HC ₅ Hn-, or alkenyl, especially CH ₂ = CH-, E-CH ₃ -CH = CH-, CH ₂ = CH-CH ₂ -CH ₂ -, E-CH ₃ -CH = CH-CH ₂ -CH ₂ - or EHC ₃ H ₇ -CH = CH-,

one of the existing rings

L ⁴¹ and L ⁴² independently = C (X ⁴ ) - and one of L ⁴¹ and L ⁴² alternatively also = N-, wherein preferably at least one of L ⁴¹ and L ⁴² = C (-F) - and the other = C (-F) - or = C (-CI) -, more preferably L ⁴¹ and L ⁴² both = C (-F) -,

X ^" F, Cl, OCF ₃ , CF ₃ , CH ₃ , CH ₂ F, CHF ₂ , preferably F or Cl, particularly preferably F,

and the other rings, if any, each independently

prefers

or more preferably

prefers

particularly preferred

one of the rings

particularly preferred

or preferred

particularly preferred

preferred and the others, if any, each independently

prefers

prefers

together optionally also a single bond,

being in the event that

means, then preferred

R 52

H,

Z ⁴¹ to Z ⁴³ and Z ⁵¹ to Z ⁵³ each independently of one another have one of the meanings given for Z ¹¹ to Z ¹³ and preferably -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 more preferably -CH ₂ -O- or a single bond,

Z ₇ 4 ^* 1 'to Z 43 preferably each independently of one another -CH ₂ -CH ₂ -, -CH ₂ -CF ₂ -, -CF ₂ -CH ₂ -, -CF ₂ -CF ₂ -, - CH = CH- , -CF = CH-, -CH = CF-, -C≡C-, -CH ₂ -O-, -O-CH ₂ -, -O-, -CH ₂ -, -CO-O-, -O -CO-, -CF ₂ -O-, -O-CF ₂ - or a single bond, preferably -CH ₂ -CH ₂ -, -CH = CH-, -C≡C-, -CF ₂ -O-, - 0-CF ₂ - or a single bond, more preferably one or, if present, more of Z ⁴¹ to Z ⁴³ a single bond, and most preferably all a single bond,

Z ⁵¹ to Z ⁵³ preferably each independently of one another -CH ₂ -CH ₂ -, -CH ₂ -CF ₂ -, -CF ₂ -CH ₂ -, -CF ₂ -CF ₂ -, - CH = CH-, -CF = CH, -CH = CF-, -C≡C-, -CH ₂ -O-, -O-CH ₂ -, -O-, -CH ₂ -, -CO-O-, -O-CO-, -CF ₂ -O-, -O-CF ₂ - or a single bond, preferably -CH ₂ -CH ₂ -, -CH = CH-, -C≡C-, -CF ₂ -O-, -O-CF ₂ or a single bond, more preferably one or, if present, several Z to Z a single bond, and most preferably all a single bond, r and s are each independently 0 or 1,

(r + s) preferably 0 or 1,

t and u are each independently, 0 or 1,

(t + u) preferably 0 or 1, preferably 0,

mean, wherein the compounds of formula II are excluded from the compounds of formula IV, and optionally

e) a chiral component (component E) consisting of one or more chiral compounds,

contains.

Preferably, the media of the invention are dielectrically negative.

The medium according to the invention preferably contains one, two, three, four or more, preferably one, two or three or more, compounds of the formula I.

Particular preference is given to compounds of the formula I in which

a) R ¹¹ and / or R ¹² H _{1 are} alkyl, alkenyl or alkoxy, preferably with up to 6 CC - AAttoommeenn ,, R ¹² very particularly preferably alkoxy or alkenyloxy,

b) R ¹¹ and R ^{12 are} both alkyl, where the alkyl radical may be the same or different,

c) R ^{11 is} straight-chain alkyl, vinyl, 1-alkenyl or 3-alkenyl.

If R ¹¹ and / or R ^{12 are} alkenyl, this is preferably CH ₂ = CH-, CH ₃ -CH = CH-, CH ₂ = CH-C ₂ H ₄ - or CH ₃ -CH = CH-C ₂ H ₄ -. The compounds of the formula I are preferably selected from the group of the compounds of the formulas 1-1 to I-4, preferably from the group of the formulas 1-1 and I-3, particularly preferably of the formula 1-1,

wherein the parameters have the respective meaning given above under formula I and preferred

and

each independently

particularly preferably independently of one another

mean.

The compounds of the formula I are preferably selected from the group of the compounds of the formulas 1-1 a to l-4a, preferably from the group of the formulas 1-1 a and l-3a, particularly preferably of the formula 1-1 a,

wherein the parameters have the meaning given above and preferred

in formulas 1-1 a and l-2a

Z ^{11 is} -CH ₂ -CH ₂ -, -CH ₂ -O- or a single bond, preferred

-CH ₂ -O- or a single bond, more preferably -CH ₂ -O-,

in formulas I-3 and I-4

Z ¹¹ -CH ₂ -CH ₂ - or a single bond, preferably one

Single bond and

Z ^{12 is} -CH ₂ -CH ₂ -, -CH ₂ -O- or a single bond, preferably -CH ₂ -O- or a single bond, more preferably

-CH ₂ -O-

mean.

Very particular preference is given to the following compounds which are compounds of the formulas 1-1 a-1, 1-1 a-2, 1-3a-1 and 1-3a-2

wherein the parameters have the meaning given above and R, 11 is preferably alkyl having 1 to 7, preferably having 1 to 5, carbon atoms, preferably n-alkyl and R ^{12 is} preferably alkoxy having 1 to 5, preferably 2 to 4, C - atoms mean.

The compounds of the formula II are preferably selected from the group of the compounds of the formulas 11-1 to II-5, preferably of the formula

I-2,

wherein

R ^■ , 21 and I ι R-> 22 have the meaning given above and

R 21 preferably alkyl with 1 to 7, preferably with 1 to 5, carbon atoms, preferably n-alkyl,

R 22 preferably alkyl with 1 to 5, particularly preferably with 2 to 4, C-atoms,

X ²² to X ²⁶ independently of one another H or F ₁ and

one of X ²⁷ and X ²⁸ H and the other H or F,

Preferably, the X ²² to X ^{28 present} all H or one or two of X ²² to X ²⁸ F and the other H

mean.

In a particularly preferred embodiment, the medium contains one or more compounds of formula 11-1 selected from the group of the compounds of the formulas II-1a to H-Id ₁ preferably of the formulas II-1 b and / or 11-1 d, particularly preferably of the formula 11-1 b,

wherein

Alkyl and alkyl 'independently of one another alkyl having 1 to 7 carbon atoms, preferably having 2 to 5 carbon atoms

Alkoxy alkoxy having 1 to 7 carbon atoms, preferably having 2 to 4 carbon atoms and

Alkenyl alkenyl having 2 to 7 carbon atoms, preferably having 2 to 5 carbon atoms.

Preferably, the concentration of these biphenyl compounds in the total mixture is 3% or more, more preferably 5% or more, and most preferably from 5 to 25%. In a further preferred embodiment, the medium contains one or more compounds of the formula 11-2, selected from the group of the compounds of the formulas II-2a to II-2d, preferably of the formulas II-2a and / or II-2c, more preferably the Formula II-2a,

wherein

Alkoxy alkoxy having up to 1 to 5 C atoms, preferably with 2 to 4 C

Atoms and

Alkenyl alkenyl having 2 to 7 carbon atoms, preferably 2 to 5 carbon atoms

atoms

and / or the group of compounds of the formulas II-2e to II-2i

wherein

R has the meaning given above for R, 41 and

m is an integer from 1 to 6.

R is preferably straight-chain alkyl or alkoxy having in each case 1 to 6 C atoms or alkoxyalkyl, alkenyl or alkenyloxy having 2-6 C atoms, particularly preferably alkyl having 1-5 C atoms, preferably methyl, ethyl, propyl, butyl, or furthermore alkoxy having 1-5 C atoms, preferably hexyl, methoxy, ethoxy, propoxy, or butoxy.

In a further preferred embodiment, the medium contains one or more compounds of the formula II-3 selected from the group the compounds of the formulas II-3a to III-III, preferably of the formulas II-3a and / or II-3c, particularly preferably of the formula II-3a,

wherein

Alkyl and alkyl ^{1 are} independently alkyl having 1 to 7 carbon atoms, preferably having 2 to 5 carbon atoms

Alkoxy alkoxy having up to 1 to 7 carbon atoms, preferably having 2 to 4 carbon atoms and

Alkenyl alkenyl having 2 to 7 C atoms, preferably having 2 to 5 C atoms

and / or the group of compounds of the formulas II-3e to II-3m

wherein

R has the meaning given above for R, 41 and

m is an integer from 1 to 6.

R is preferably straight-chain alkyl or alkoxy having in each case 1 to 6 C atoms or alkylalkoxy, alkenyl or alkenyloxy having 2-6 C atoms, particularly preferably alkyl having 1-5 C atoms, preferably methyl, ethyl, propyl, butyl, or furthermore alkoxy having 1-5 C atoms, preferably hexyl, methoxy, ethoxy, propoxy, or butoxy.

In a further preferred embodiment, the medium contains one or more compounds of the formula III in which at least two of the rings

each independently

and or

most preferably two adjacent rings are directly linked, and although preferred

mean, wherein in the phenylene ring one or more H atoms, independently of one another by F or CN, preferably by F and one or two non-adjacent CH ₂ groups of the cyclohexylene ring or one of the two cyclohexylene rings may be replaced by O atoms.

In a further preferred embodiment, the medium contains one or more compounds of the formula III from the group of the compounds of the formulas III-1 to III-II, preferably selected from the group of the compounds of the formulas III-III to III-9, preferably from Group III-1 to III-6 and more preferably from the group UM and III-4,

wherein the parameters have the meaning given above for formula III and

H or F means and preferably

R> ³ 31 alkyl or alkenyl and

R i ^J 32 alkyl, alkenyl or alkoxy, preferably alkyl or alkenyl, particularly preferably alkenyl.

The medium particularly preferably contains one or more compounds of the formula III-1 selected from the group of the formulas III-1c, particularly preferably of the formula III-1 in which R ^{31 is} vinyl or 1-propenyl and R ^{32 is} alkyl π-alkyl, particularly preferably R ^{31 is} vinyl and R ^{32 is} propyl and of the formulas III-1d, particularly preferably of the formula III-1 in which R ³¹ and R ³² independently of one another are vinyl or 1-propenyl, preferably and R ^{31 is} vinyl and particularly preferably R ³¹ and R ^{32 are} vinyl.

In a further preferred embodiment, the medium contains one or more compounds of the formula III-1 selected from the group of the compounds of the formulas III-1 to III-Ie, preferably of the formulas III-1a and / or Formulas III-1c and / or III-Id, particularly preferably of the formulas III-1C and / or IH-Id and very particularly preferably of the formula II-1-1C and of the formula II 1-1CJ,

wherein

Alkoxy alkoxy having 1 to 5 carbon atoms, preferably having 2 to 4 carbon atoms and Alkenyl and alkenyl 'independently, alkenyl having 2 to 7 carbon atoms, preferably having 2 to 5 carbon atoms.

The medium according to the invention particularly preferably contains compounds of the formula III-1 in amounts of 20% or more, in particular of 25% or more, very particularly preferably of 30% or more, in particular compounds of the formula III-Ic '

wherein

n = 3, 4, 5 and R ^{e is} H or CH ₃

mean.

In a further preferred embodiment, the medium contains one or more compounds of the formula III-1 selected from the group of the compounds of the formulas IIIa and Ib-Ib, preferably of the formulas II-1a and / or III-1b, particularly preferably of formula IM-I a. In this embodiment, the medium preferably contains no compounds of the formula III, preferably of the formula III-1, with one alkenyl end group or more

Alkenyl end groups, so preferably no compounds of the formulas III-1 C to Ml-Ie. The medium in this embodiment particularly preferably contains one or more compounds selected from the group of the compounds of the formulas CC-2-3, CC-2-5, CC-3-4 and CC-3-5, the acronyms (abbreviations) in Tables A to C and illustrated in Table D by Examples.

In a further preferred embodiment, the medium contains one or more compounds of the formula IM-2 selected from the group of the compounds of the formulas III-2a to III-2d, preferably of the formulas III-2a and / or III-2b, particularly preferably of the formula III-2b,

wherein

Alkoxy alkoxy having 1 to 5 carbon atoms, preferably having 2 to 4 carbon atoms and

In a further preferred embodiment, the medium contains one or more compounds of the formula III-3 selected from the group of the compounds of the formulas III-3a to III-3c

wherein

Alkyl and alkyl 'independently of one another are alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms, alkenyl alkenyl having 2 to 7 C atoms, preferably 2 to 5

C atoms mean.

The proportion of these biphenyls in the total mixture is preferably 3% or more, especially 5% or more. Preferred compounds of the formulas III-3a or III-3b are the compounds of the following formula

wherein the parameters have the meanings given above.

Particularly preferred compounds of formula III-3b are the compounds of the following formula

and in particular those of the last formula. In a preferred embodiment, the medium contains one or more compounds of the formula III-4, particularly preferably one or more compound (s) in which R ^{31 is} vinyl or 1-propenyl and R ^{32 is} alkyl, preferably n-alkyl, particularly preferably R ³¹ Vinyl and R ^{32 are} methyl.

In a further preferred embodiment, the medium contains one or more compounds of the formula III-4 selected from the group of the compounds of the formulas III-4a to III-4d, preferably of the formulas III-4a and / or III-4b, more preferably the Formula III-4b,

wherein

Alkyl and alkyl 'independently of one another are alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms, alkoxyalkoxy having up to 1 to 5 C atoms, preferably 2 to

4 C atoms and

In a preferred embodiment, the medium contains one or more compounds of the formula III-5, particularly preferably one or more compound (s) in which R 31 is alkyl, vinyl or 1-propenyl and R ^{32 is} alkyl, preferably π-alkyl.

In a further preferred embodiment, the medium contains one or more compounds of the formula III-5 selected from the group of the compounds of the formulas III-5a to III-5d, preferably of the formulas III-5a and / or III-5b, particularly preferably of the formula III-5a

embedded image in which

Alkoxy alkoxy having up to 1 to 5 carbon atoms, preferably having 2 to 4 carbon atoms and

and / or the formulas III-5e to III-5h, preferably of the formulas III-5e and / or III-5f, particularly preferably of the formula III-5e

wherein

Alkyl and alkyl ^{1 are} independently alkyl having 1 to 7 carbon atoms, preferably having 2 to 5 carbon atoms Alkoxy alkoxy having up to 1 to 5 carbon atoms, preferably having 2 to 4 carbon atoms and

In a further preferred embodiment, the medium contains one or more compounds of the formula III-6 selected from the group of the compounds of the formulas III-6a to III-6c, preferably of the formulas III-6a and / or III-6b, particularly preferably of the formula ml-Ga

wherein

Alkyl and alkyl 'independently of one another alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms,

Alkoxy alkoxy having up to 1 to 5 carbon atoms, preferably having 2 to 4 carbon atoms, and

The inventive media particularly preferably contain one or more compounds selected from the compounds of the Formulas III-6a, preferably selected from the group of compounds PGP-2-3, PGP-3-3 and PGP-3-4, and of formula III-6b, preferably selected from the group of the formulas PGP-1-2V, PGP-2-2V and PGP-3-2V, the acronyms (abbreviations) being illustrated in Tables A to C and illustrated in Table D by Examples.

In another preferred embodiment, the medium contains one or more compounds of formula III-10 selected from the group of compounds of formulas MI-IOa and MI-IOb

wherein

Alkyl and alkyl 'independently of one another are alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms.

In a further preferred embodiment, the medium contains one or more compounds of the formula III-II of the compounds of the formulas III-IIa

wherein

Alkyl and alkyl 'independently of one another are alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms. In a preferred embodiment, the medium contains one or more compounds of the formula IV ₁ selected from the group of the compounds of the formulas IVA to IVD, preferably IVA to IVC and very particularly preferably IVA and IVB

wherein the parameters have the meanings given above, in formula IVA

and not

and preferred

and

independently of each other

and especially preferred

R 41 alkyl,

R 42 is alkyl or alkoxy, more preferably (O) CvH _2v + i.

X ⁴¹ and X ⁴² both F,

Z ²¹ and Z ^{22 are} independently a single bond,

-CH ₂ -CH ₂ -, -CH = CH-, -CH ₂ O-, -OCH ₂ -, -O-, -CH ₂ -, -CF ₂ O-, or -OCF ₂ -, preferably a single bond or -CH ₂ CH ₂ -, more preferably a single bond,

p 1 or 2, and

1 to 6

mean. In a preferred embodiment, the medium contains one or more compounds of the formula IV selected from the group of the compounds of the formulas IV-1 to IV-9

wherein

Y ⁴¹ to Y ⁴⁶ independently of one another H or F, and

X ⁴¹ and X ⁴² both H or one of X ⁴¹ and X ⁴² H and the other F,

but preferably at most four, more preferably at most three, and most preferably one or two, from Y ⁴¹ to Y ⁴⁶ ,

X ⁴¹ and X ⁴² F,

mean and

the remaining parameters have the respective meaning given above for formula IV and preferred

R 41 is alkyl or alkenyl and

, 42 alkyl, alkenyl, alkoxy or alkenyloxy, preferably (O) C _v H _2v + i and

an integer from 1 to 6.

In a further preferred embodiment, the medium contains one or more compounds of the formula IV-1 selected from the group of the compounds of the formulas IV-Ia to IV-Id, preferably of the formulas IV-I b and / or IV-Id, particularly preferably of the formula IV-I b,

wherein

Alkoxy alkoxy having 1 to 7 carbon atoms, preferably 2 to 4 carbon atoms

Atoms and alkenyl alkenyl having 2 to 7 carbon atoms, preferably 2 to 5

C atoms mean.

Preferred compounds of the formulas IV-Ic or IV-Id are the compounds of the following formulas

wherein v has the meaning given above.

Further preferred compounds of formulas IV-1 are the compounds of the following formulas

wherein R ^{41 has} the meaning given above in formula IV.

In a further preferred embodiment, the medium contains one or more compounds of the formula IV-3 selected from the group of the compounds of the formulas IV-3a to IV-3d, preferably of the formulas IV-3a and / or IV-3b, more preferably of the formula IV-3b,

wherein

Preferred compounds of the formulas IV-3c or IV-3d are the compounds of the following formulas

wherein v has the meaning given above.

In a further preferred embodiment, the medium contains one or more compounds of the formula IV-3 of the following sub-formula IV-3e

wherein

R 41 has the meaning given above and

m and z are each independently an integer from 1 to 6 and m + z is preferably an integer from 1 to 6.

In a further preferred embodiment, the medium comprises one or more compounds of the formula IV-4 selected from the group of the compounds of the formulas IV-4a to IV-4d, preferably of the formulas IV-4b and / or IV-4d,

wherein

Alkenyl alkenyl having 2 to 7 carbon atoms, preferably having 2 to 5 carbon atoms. Preferred compounds of the formulas IV-4c or IV-4d are the compounds of the following formulas

wherein v has the meaning given above.

In a further preferred embodiment, the medium contains one or more compounds of the formula IV-8 selected from the group of the compounds of the formulas IV-8a and IV-8b, particularly preferably IV-8b

wherein the parameters have the meanings given above.

In a further preferred embodiment, the medium contains one or more compounds of the formula IV-9 selected from the group of the compounds of the formulas IV-9a to IV-9d

wherein the parameters have the meanings given above and preferred

R 42

C _v H _2v + i and

v is an integer from 1 to 6.

In a further preferred embodiment, the medium contains one or more compounds of the formula IV-10 selected from the group of the compounds of the formulas IV-IOa to IV-IOe

wherein the parameters have the meanings given above and preferred

R 42

C _v H2v + i and v is an integer from 1 to 6.

In a further preferred embodiment, the medium contains one or more compounds of the formula IV-11 selected from the group of the compounds of the formulas IV-11a and IV-11b, particularly preferably IV-11b

wherein the parameters have the meanings given above.

In a further preferred embodiment, the medium contains one or more compounds of the formula IV-9 selected from the group of the compounds of the formulas IV-9a to IV-9d, preferably of the formulas IV-9a and / or IV-9b, more preferably the Formula IV-9b,

wherein

Alkyl and alkyl 'independently of one another alkyl having 1 to 7 carbon atoms, preferably having 2 to 5 carbon atoms Alkoxy alkoxy having 1 to 7 carbon atoms, preferably having 2 to 4 carbon atoms and

In a further preferred embodiment, the medium additionally contains one or more compounds of the formula V, preferably selected from the group of the compounds of the formulas V-1 to V-8, preferably of the formulas V-7 and / or V-8

wherein the parameters have the respective meaning given above for formula V and preferred

R 51 is alkyl or alkenyl and

R 52 is alkyl, alkenyl, alkoxy or alkenyloxy,

In this embodiment, preferably when the medium contains one or more compounds of the formulas V-7 and / or V-8, the medium may consist essentially of compounds of the formulas I, II, III and V.

In a further preferred embodiment, the medium additionally contains one or more compounds which have a fluorinated phenanthrene unit, preferably compounds of the formula V, preferably selected from the group of the compounds of the formulas V-9 and V-10

wherein the parameters have the meaning given above for formula V and preferably R ^{51 is} alkyl or alkenyl and

R ^{52 is} alkyl, alkenyl, alkoxy or alkenyloxy.

In a further preferred embodiment, the medium additionally contains one or more compounds which have a fluorinated dibenzofuran unit, preferably compounds of the formula V, preferably of the formula V-11

wherein the parameters have the meaning given above for formula V and preferably, _Λ

R ^{51 is} alkyl or alkenyl and

R ^{52 is} alkyl, alkenyl, alkoxy or alkenyloxy.

In a further preferred embodiment, the medium additionally contains one or more compounds which have a fluorinated indane unit, preferably selected from the group of the compounds of the formulas V-12a and V-12b

R 51 is alkyl or alkenyl and

R 52 is alkyl, alkenyl, alkoxy or alkenyloxy,

₇ 51 a single bond and

0

mean.

Very particular preference is given to the compounds of the formula V-12b '

wherein R ^{51 has} the meaning given above and is preferably alkyl having 1 to 7, preferably having 1 to 5, carbon atoms, preferably n-alkyl.

The chiral compound or chiral compounds that can be used in component E of the liquid crystal media according to the present invention are selected from the known chiral dopants. The component E preferably exists predominantly, particularly preferably substantially and very particularly preferably almost completely, of one or more compounds selected from the group of the compounds of the following formulas VI to VIII

wherein

R ⁶¹ and R ⁶² , R ⁷¹ to R ⁷³ and R ^{8 are} each independently of one another, which oobbeenn bbeei FFoorrmmeell IIll ffüürr RR ²²¹¹ ggeeggeebbeennee BBeeddeeuuttuunngg bbeessiittzzeen, and alternatively H, CN, F, Cl C -FF ₃₃ , OOCCFF ₃₃ ,, CF ₂ H or OCF ₂ H and at least one of R and R represents at least one chiral group,

Z ⁶¹ and Z ⁶² , Z ⁷¹ to Z ⁷³ and Z ^{8 are} each independently -CH ₂ CH ₂ -, -CH = CH-, -COO-, -O-CO- or a single bond, preferably Z ⁶¹ , Z ⁶² , Z ⁷¹ , Z ⁷⁴ and Z ^{75 are} a single bond, Z ⁶³ , Z ⁷² and Z ^{73 are} -COO- or a single bond, Z ^{72 is} preferably -COO- and Z ⁷³ and Z ^{8 is} -O-CO-,

each independently

u and v, and x, y and z are each independently 0 or 1, preferably

u and v both 0 and

x and v are both 1, mean.

Particularly preferred embodiments of the present invention fulfill one or more of the following conditions.

i. The liquid crystalline medium has a birefringence of 0.095 or more.

ii. The liquid-crystalline medium contains one or more

Compounds selected from the group of the sub-formulas 1-1 to I-4 iii. The concentrations of the individual homologous compounds of the formula I are in the range from 1 to 20%, preferably from 2 to 15% and particularly preferably from 3 to 10%.

iv. The proportion of compounds of the formula II in the total mixture is

10% or more, preferably 50% or less, and more preferably 15% or more.

v. The liquid-crystalline medium contains one or more compounds of formula 11-1, preferably 11-1 b and / or ll-1d, more preferably 11-1 b, preferably in a total concentration of 60% or less and in a concentration of 2% or more, in particular of 5% or more, and most preferably from 5% or more to 15% or less per homologous individual compound.

vi. The liquid-crystalline medium contains one or more

Compounds of formula II-2 and / or II-3, preferably of formulas II-2a and / or II-3a, preferably in a total concentration of 50% or less and preferably in a concentration of 2% or more to 10% or less per homologous single compound of the formula II-3 and in a concentration of 2% or more to 15% or less per homologous individual compound of the formula II-3.

vii. The proportion of compounds of the formula III in the total mixture is 10% or more, preferably 70% or less and particularly preferably 15% or more.

viii. The liquid-crystalline medium contains one or more particularly preferred compounds of the formulas Ml-Ic and Ml-Id selected from the following partial formulas:

wherein alkyl has the meaning given above and preferably, in each case independently of one another alkyl having 1 to 6, preferably having 2 to 5 carbon atoms and particularly preferably n-alkyl. ix. The liquid-crystalline medium contains one or more

Compounds of the formula III selected from the group of the following formulas

wherein R ³¹ and R ^{32 have} the abovementioned meaning and preferably R ³¹ and R ^{32 are} each independently a straight-chain alkyl, alkoxy or alkenyl radical having 1 or 2 to 7 C atoms, particularly preferably straight-chain alkyl, furthermore alkenyl mean.

The proportion of these compounds in the mixture is preferably 5 to 40%.

The liquid-crystalline medium contains one or more

Compounds of the formula IM selected from the group of

Compounds of the following formulas: CC-nV and / or CC-n-Vm (eg preferably CC-5-V preferably in a concentration of up to 25% or less, CC-3-V, preferably in a concentration of up to 60% or less and / or CC-3-V1, preferably in a concentration of up to 25% or less and / or CC-4-V, preferably in one

Concentration of up to 40% or less,)

CC-nm and / or CC-n-Om (eg: preferably CC-3-2 and / or CC-3-3 and / or CC-3-4 and / or CC-3-O2 and / or CCP-5 -02), CP-nm and / or CP-n-Om (eg: preferably CP-3-2 and / or CP-5-2 and / or CP-3-O1 and / or CP-3-O2), PP-n-Vm (eg: preferably PP-n-2V), PP-n-IVm (eg: preferably PP-n-2V1), CCP-nm

(eg, preferably CCP-n-1), CPP-nm, CGP-nm and CCOC-nm, wherein the meaning of the Akonyme (abbreviations) in Tables A to C are illustrated and illustrated in Table D by examples, preferably in a total concentration from up to 10% or more to 70% or less.

The liquid-crystalline medium consists essentially of

2% to 80% of one or more compounds of the formula I,

2% to 80% of one or more compounds of the formula II, 2% to 80% of one or more compounds of formula IM and / or

2% to 80% of one or more compounds selected from the group of the compounds of the formulas IV and / or V.

xii. The liquid-crystalline medium contains one or more compounds of the formula I having four six-membered or ten-membered rings or ring systems in amounts of from 1% to 15%, in particular from 2% to 12%, and very particularly preferably from 3 to 8%, per individual compound.

xiii. The liquid-crystalline medium contains one or more

Compounds of formula IV, preferably in amounts of 2% or more, in particular of 5% or more, and very particularly preferably of 5% or more to 25% or less, in particular in the range of 2% or more to 12% or less per homologous single connection.

xiv. The liquid-crystalline medium contains one or more

Compounds of the formula IV-1 to IV-2, preferably IV-1 and / or IV-2, preferably of the formulas IV-Ib and / or IV-Id, particularly preferably IV-1b, preferably in a total concentration of 60% or less and in a concentration of 2% or more, especially 5% or more, and most preferably from 5% or more to 20% or less per homologous single compound.

xv. The liquid-crystalline medium contains one or more

Compounds of the formula IV-3 and / or IV-4, preferably of the formulas IV-3b and / or IV-3d and / or IV-4b and / or IV-4d, particularly preferably IV-4b and / or IV-4b, preferably in a total concentration of 60% or less and in a concentration of 2% or more, more preferably 5% or more, and most preferably 5% or more to 20% or less per homologous single compound. xiv. The liquid-crystalline medium contains one or more

Compounds of formula IV preferably in amounts of 2% or more, in particular of 5% or more, and very particularly preferably from 5% to 25%, in particular in the range of 2% to 12%, per individual compound.

xvii. The liquid-crystalline medium contains one or more

Compounds of the formula V preferably in amounts of 3% or more, in particular of 5% or more, and very particularly preferably of 5% to 25%, in particular in the range of 2% to 20

% per single connection.

xviii. The liquid-crystalline medium contains one or more

Compounds selected from the compounds of the formulas V-12a and V-12b, preferably in a total amount of 10% or more. The concentrations of the individual homologous compounds of the formulas V-12a and / or V-12b are preferably from 2 to 15%, preferably from 3 to 12% and particularly preferably from 4 to 10%.

Another object of the invention is an electro-optical display with an active matrix addressing based on the ECB effect, characterized in that it contains as a dielectric liquid-crystalline medium according to the present invention.

Preferably, the liquid crystal mixture on a nematic phase range of at least 60 degrees and a flow viscosity V ₂ O of at most 30 mm ² • s ^"1 at 20 ⁰ C.

The liquid-crystal mixture according to the invention has a Δε of about -0.5 to -8.0, in particular of about -2.5 to -6.0, where Δ∈ denotes the dielectric anisotropy. The rotational viscosity y - _\ is preferably 200 mPa · s or less, more preferably 170 mPa · s or less. The birefringence Δn in the liquid-crystal mixture is usually between 0.06 and 0.16, preferably between 0.08 and 0.12. The mixtures according to the invention are suitable for all VA TFT applications, such as, for example, VAN, MVA, (S) -PVA and ASV. Furthermore, they are suitable for IPS (Jn pjane switching), FFS (fringe field switching) and PALC applications with negative Δε.

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

For component A, one (or more) individual compound (s) is preferably selected which have a value of Δε <-0.8. This value must be the more negative the smaller the proportion A of the total mixture is.

For component B, one (or more) individual compound (s) is preferably selected which have a value of Δε <-0.8. This value must be the more negative, the smaller the proportion B of the total mixture.

The component C has a pronounced nematogeneity and a flow viscosity of not more than 30 mm ² • s ^-1 , preferably not more than 25 mm ² s ^-1 , at 20 ^° C.

Particularly preferred individual compounds of component C are extremely low-viscosity nematic liquid crystals having a flow viscosity of not more than 18, preferably not more than 12 mm ² • s ^{' 1} , at 20 ^° C.

Component C is monotropic or enantiotropic nematic and can be found in

Liquid crystal mixtures prevent the occurrence of smectic phases up to very low temperatures. If, for example, a smectic liquid-crystal mixture is mixed with in each case different materials with high nematogeneity, the degree of suppression of smectic phases achieved can be used to compare the nematogeneity of these materials.

The skilled worker is known from the literature a variety of suitable materials. Particular preference is given to compounds of the formula III.

In addition, these liquid crystal phases may also contain more than 18 components, preferably 18 to 25 components. Preferably, the phases contain 4 to 15, in particular 5 to 12, and particularly preferably 10 or less, compounds of the formulas I and II and / or III and / or IV and / or V.

In addition to compounds selected from the group of formulas I to V, other ingredients may be present, for. B. in an amount of up to 45% of the total mixture, but preferably up to 35%, in particular up to 10%. The other constituents are preferably selected from the nematic or nematogenic substances, in particular the known substances, from the classes of the azoxybenzenes, benzylideneanilines, biphenyls, terphenyls, phenyl or cyclohexyl benzoates, cyclohexane-carboxylic acid phenyl or cyclohexyl esters, phenylcyclohexanes, cyclohexyl biphenyls, cyclohexylcyclohexanes, cyclohexylnaphthalenes, 1,4-biscyclohexylbiphenyls or cyclohexylpyrimidines, phenyl- or cyclohexyldioxanes, optionally halogenated stilbenes, benzylphenyl ethers, tolans and substituted cinnamic acid esters.

The most important compounds which can be considered as constituents of such liquid-crystal phases can be characterized by the formula IX,

R ⁹¹ -LGER ⁹² IX

where L and E are each a carbo- or heterocyclic ring system of the 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, di- and tetrahydronaphthalene, quinazoline and tetrahydroquinazoline,

-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 -

- (CHz) ₄ - - (CHz) ₃ O-

or a CC single bond, Q is halogen, preferably chlorine, or -CN, and R ⁹¹ and R ^{92 are} each alkyl, alkenyl, alkoxy, alkanoyloxy or alkoxycarbonyloxy having up to 18, preferably up to 8 carbon atoms, or one of these radicals also CN, NC, NO ₂ , NCS, CF ₃ , OCF ₃ , F, Cl or Br.

In most of these compounds, R ⁹¹ and R ⁹² are different from each other, one of these radicals is usually an alkyl or alkoxy group. Other variants of the substituents provided are also in use. Many such substances or mixtures thereof are commercially available. All these substances can be prepared by literature methods.

The concentration of the compounds of formula IX in the total mixture is preferably 1% to 25%, more preferably 1 to 15% and most preferably 2% to 9%.

Optionally, the media of the invention may also contain a dielectrically positive component whose total concentration is preferably 10% or less based on the total medium.

In a preferred embodiment, the liquid-crystal media according to the invention contain 5% or more to 60% or less, preferably 10% or more to 50% or less, preferably 15% or more to 40% or less and particularly preferably 20% or in total, based on the total mixture more to 35% or less and most preferably 25% or more to 30% or less of component A and

1% or more to 45% or less, preferably 2% or more to 40% or less, preferably 3% or more to 35% or less, and more preferably 5% or more to 30% or less and most preferably 10% or more to 20% or less of component B and

5% or more to 80% or less, preferably 25% or more to 75% or less, more preferably 35% or more to 70% or less and most preferably 40% or more to 65% or less of Component C. Where the respective different preferred ranges of the concentrations of the respective different components can be combined with one another as desired, but the total concentration of all compounds and of all components does not exceed 100% in each case.

In a preferred embodiment, the liquid-crystal media according to the invention comprise components A and C and preferably one or more components selected from the group of components B, D and E, preferably predominantly, more preferably substantially and very preferably almost completely, of said components ,

The liquid crystal media according to the invention preferably have a nematic phase of at least from -20 ⁰ C or less to 70 ⁰ C or more, more preferably from -30 ⁰ C or less to 80 ⁰ C or more, very particularly preferably from -40 ⁰ C or less to 85 ° C or more, and even most preferably at from -40 ⁰ C or less to 90 ° C or more.

On the one hand, the term "having a nematic phase" means that no smectic phase and no crystallization are observed at low temperatures at the corresponding temperature and, on the other hand, that no clarification occurs during heating from the nematic phase a flow viscometer at the appropriate temperature and checked by storage in test cells of the electro-optical application corresponding layer thickness for at least 100 hours. When the storage stability at a temperature of -20 ° C in a corresponding test cell is 1,000 hours or more, the medium is said to be stable at this temperature. At temperatures of -30 ⁰ C or -40 ⁰ C, the corresponding times are 500 h or 250 h. At high temperatures, the clearing point by conventional methods in

Capillaries measured.

In a preferred embodiment, the liquid-crystal media according to the invention are characterized by values of the optical anisotropies in the middle to low range. The values of the birefringence are preferably in the range of 0.065 or more to 0.130 or less, more preferably in the range of 0.080 or more to 0.120 or less and most preferably in the range of 0.085 or more to 0.110 or less.

In this embodiment, the liquid crystal media of the invention have a negative dielectric anisotropy and have relatively high values of the amount of dielectric anisotropy (IΔεl), preferably in the range of 2.7 or more to 5.3 or less, preferably to 4.5 or less, preferably from 2.9 or more to 4.5 or less, more preferably from 3.0 or more to 4.0 or less, and most preferably from 3.5 or more to 3.9 or less.

The liquid-crystal media according to the invention have relatively small values for the threshold voltage (V ₀ ) in the range of 1, 7 V or more to 2.5 V or less, preferably from 1, 8 V or more to 2.4 V or less, more preferably from 1, 9 V or more to 2.3 V or less, and more preferably from 1.95 V or more to 2.1 V or less.

In a further preferred embodiment, the liquid-crystal media according to the invention preferably have relatively low values of the average dielectric anisotropy (ε _av = (εn + 2εχ) / 3), which is preferably in the range from 5.0 or more to 7.0 or less from 5.5 or more to 6.5 or less, even more preferably from 5.7 or more to 6.4 or less, more preferably from 5.8 or more to 6.2 or less and most preferably from 5.9 or more to 6.1 or less.

In a preferred embodiment, which is particularly suitable for use in LCD TV displays, the inventive

Liquid-crystal media values of the amount of dielectric anisotropy (I Δεl), which preferably in the range of 1, 7 or more to 4.9 or less, preferably to 4.3 or less, preferably from 2.3 or more to 4.0 or less, more preferably from 2.8 or more to 3.8 or less.

In this embodiment, the liquid crystal media of the present invention have values for the threshold voltage (V ₀ ) ranging from 1.9 V or more to 2.5 V or less, preferably from 2.1 V or more to 2.3 V or less.

In addition, the liquid-crystal media according to the invention have high levels

Values for the voltage holding ratio in liquid crystal cells.

These are in freshly filled cells at 20 ⁰ C in the cells greater than or equal to 95%, preferably greater than or equal to 97%, more preferably greater than or equal to 98% and most preferably greater than or equal to 99% and after 5 minutes in the oven at 100 ⁰ C in the cells greater than or equal to 90%, preferably greater than or equal to 93%, more preferably greater than or equal to 96% and most preferably greater than or equal to 98%.

As a rule, liquid crystal media with a low drive voltage or threshold voltage have a lower voltage holding ratio than those with a larger drive voltage or threshold voltage and vice versa.

These preferred values for the individual physical properties are preferably also kept in combination with one another by the media according to the invention. In the present application, the term "compounds", also written as "compound (s)", unless explicitly stated otherwise, means both one or more compounds.

The individual compounds are, unless stated otherwise, in the mixtures in concentrations generally from 1% or more to 30% or less, preferably from 2% or more to 30% or less, and more preferably from 3% or more to 16% or less used. For the purposes of the present invention, in connection with the indication of the constituents of the compositions, if not stated otherwise in individual cases:

"Contain": the concentration of the constituents in the composition is preferably 5% or more, more preferably 10% or more, most preferably 20% or more,

"Predominantly consisting of": the concentration of the constituents in the composition is preferably 50% or more, more preferably 55% or more and most preferably 60% or more,

- "consist essentially of": the concentration of the constituents in question in the composition is preferably 80% or more, more preferably 90% or more and most preferably 95% or more and - "almost completely composed" means the concentration of the substances concerned Ingredients in the composition is preferably 98% or more, more preferably 99% or more, and most preferably 100.0%.

This applies both to the media as compositions with their

Components, which may be components and compounds, as well as the components with their constituents, the compounds. Only in relation to the concentration of a single compound in relation to the total medium does the term contain: the concentration of the compound in question is preferably 1% or more, more preferably 2% or more, most preferably 4% or more. For the present invention, "<" means less than or equal to, preferably less than and ">" greater than or equal to, preferably greater.

For the present invention

trans-1, 4-cyclohexylene and

1, 4-phenylene.

For the present invention, the terms "dielectrically positive compounds" mean those compounds having a Δε> 1.5, "dielectrically neutral compounds" those having -1, 5 <Δε <1, 5 and "dielectrically negative" compounds those having Δε <- 1, 5. In this case, the dielectric anisotropy of the compounds is determined by dissolving 10% of the compounds in a liquid-crystalline host and determining the capacity of the resulting mixture in at least one test cell with 20 μm layer thickness with homeotropic and with homogeneous surface orientation at 1 kHz The measurement voltage is typically 0.5 V to 1.0 V, but it is always lower than the capacitive threshold of the respective liquid-crystal mixture investigated.

The host mixture used for dielectrically positive and dielectrically neutral compounds is ZLI-4792 and for dielectrically negative compounds ZLI-2857, both from Merck KGaA, Germany. From the change in the dielectric constant of the host mixture after addition of the test compound and extrapolation to 100% of the compound used, the values for the respective compounds to be investigated are obtained. The compound to be tested is dissolved to 10% in the host mixture. If the solubility of the substance is too low for this purpose, the concentration is gradually reduced by half until the test can be carried out at the desired temperature. If necessary, the liquid-crystal media according to the invention can also contain further additives, such as, for example, B. stabilizers and / or pleochroic dyes and / or chiral dopants in the usual amounts. The amount of these additives used is preferably 0% or more to 10% or less in total, based on the amount of the entire mixture, more preferably 0.1% or more to 6% or less. The concentration of the individual compounds used is preferably 0.1% or more to 3% or less. The concentration of these and similar additives is used to indicate concentrations and concentration ranges of

Liquid crystal compounds in the liquid crystal media are usually not considered.

In a preferred embodiment, the liquid-crystal media according to the invention contain a polymer precursor which contains one or more reactive compounds, preferably reactive mesogens and, if required, further additives such as, for example, B. polymerization initiators and / or polymerization moderators in the usual amounts. The amount of these additives used is generally 0% or more to 10% or less based on the amount of the whole mixture, preferably 0.1% or more to 2% or less. The concentration of these and similar additives is not taken into account in the indication of the concentrations and the concentration ranges of the liquid crystal compounds in the liquid-crystal media.

The compositions consist of several compounds, preferably from 3 or more to 30 or less, more preferably from 6 or more to 20 or less and most preferably from 10 or more to 16 or fewer compounds that are mixed in a conventional manner. In general, the desired amount of the minor components is dissolved in the components that make up the main ingredient of the mixture. This is conveniently carried out at elevated temperature. If the selected temperature is above the clearing point of the main constituent, the completion of the dissolution process is particularly easy to observe. However, it is also possible, the liquid crystal mixtures in other conventional ways, for. B. using premixes or from a so-called "multi-bottle system".

The mixtures according to the invention exhibit very broad nematic phase ranges with clearing points 65 ° C or more, very favorable values for the capacitive threshold, relatively high values for the holding ratio and at the same time very good low-temperature stabilities at -30 ⁰ C and -40 ⁰ C. Furthermore, characterized the mixtures according to the invention by low rotational viscosities Y ₁ from.

It will be understood by those skilled in the art that for use in VA, IPS, FFS or PALC displays, the media of this invention may also contain compounds wherein, for example, H, N, O, Cl, F are replaced by the corresponding isotopes are.

The structure of the liquid crystal displays according to the invention corresponds to the usual geometry, as z. As described in EP-OS 0 240 379.

By means of suitable additives, the liquid crystal phases according to the invention can be modified in such a way that they can be used in any kind of z. B. ECB, VAN, IPS, GH or AS M-VA LCD display can be used.

In the following Table E possible dopants are given, which can be added to the mixtures according to the invention.

If the mixtures contain one or more dopants, it is used in amounts of 0.01 to 4%, preferably 0.1 to 1, 0%.

Stabilizers which can be added, for example, to the mixtures according to the invention, preferably in amounts of from 0.01 to 6%, in particular from 0.1 to 3%, are mentioned below in Table F.

All concentrations are for the purposes of the present invention, unless explicitly stated otherwise, given in percent by weight and refer to the corresponding mixture or mixture component, unless explicitly stated otherwise. All stated values for temperatures in the present application, such. B. the melting point T (C ₁ N), the transition from the smectic (S) to the nematic (N) phase T (S ₁ N) and the clearing point T (N ₁ I), are in degrees Celsius ( ⁰ C) and all temperature differences are given according to degree of difference (° or degrees), unless explicitly stated otherwise.

The term "threshold voltage" for the present invention refers to the capacitive threshold (V ₀ ), also called Freedericksz threshold, unless explicitly stated otherwise.

All physical properties are and have been determined according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status Nov. 1997, Merck KGaA, Germany and are valid for a temperature of 20 ⁰ C and Δn is determined at 589 nm and Δε at 1 kHz unless explicitly stated otherwise.

The electro-optical properties, eg. For example, the threshold voltage (Vo) (capacitive measurement), as well as the switching behavior, are determined in test cells manufactured at Merck Japan ^Ltd. The measuring cells have substrates of sodium glass (Sodalime glass) and are in an ECB or VA configuration with polyimide orientation layers (SE-1211 with thinner ^* * 26 (mixing ratio 1: 1) both from Nissan Chemicals, Japan) which are perpendicular to each other are rubbed and that cause a homeotropic orientation of the liquid crystals carried out. The area of the transparent, nearly square electrodes made of ITO is 1 cm ² .

The liquid crystal mixtures used are not mixed with a chiral dopant unless otherwise stated, but they are also particularly suitable for applications in which such a doping is required.

The Voltage Holding Ratio is determined in test cells manufactured at Merck Japan ^Ud . The measuring cells have substrates of sodium glass

(Sodalime glass) and are coated with polyimide alignment layers (AL-3046 of Japan Synthetic Rubber, Japan) with a layer thickness of 50 nm, which are rubbed perpendicular to each other. The layer thickness is uniformly 6.0 microns. The area of the transparent electrodes made of ITO is 1 cm ² .

The voltage holding ratio is at 20 ⁰ C (HR ₂₀₎ and after 5 minutes in oven at 100 ⁰ C (HR ₁ 00) was determined. The voltage used has a frequency of 60 Hz.

The rotational viscosity is determined by the method of the rotating permanent magnet and the flow viscosity in a modified Ubbelohde viscometer. For the liquid crystal mixtures ZLI-2293, ZLI-4792 and MLC-6608, all products from Merck KGaA, Darmstadt, Germany, which determined at 20 ⁰ C values of the rotational viscosity be 161 mPas, 133 mPas and 186 MPA s and that of the flow viscosity (v) 21 mm ² -s ^"1 , 14 mm ² s ^-1 or 27 mm ² s ^{" 1} .

The following symbols are used:

V ₀ threshold voltage, capacitive [V] at 20 ⁰ C, n _e extraordinary refractive index measured at 20 ⁰ C and 589 nm, n ₀ ordinary refractive index measured at 20 ⁰ C and

589 nm,

.DELTA.n optical anisotropy measured at 20 ⁰ C and 589 nm, ε ± dielectric susceptibility perpendicular to the director at 20 ⁰ C and 1 kHz, dielectric susceptibility εμ parallel to the director at 20 ⁰ C and 1 kHz,

Dielectric anisotropy Δε at 20 ⁰ C and 1 kHz, cp. or T (N ₁ I) clearing point [° C], γi rotational viscosity measured at 20 ⁰ C [mPa-s],

Ki elastic constant, "splay" deformation at 20 ° C [pN],

K ₂ elastic constant, "twisf" deformation at 20 ° C [pN],

K ₃ elastic constant, bend deformation at 20 ° C [pN] and LTS low temperature stability, determined in

Test cells.

The following examples illustrate the present invention without limiting it. However, they show the skilled person preferred mixing concepts with preferably used compounds and their respective concentrations and their combinations with each other. In addition, the examples illustrate which properties and property combinations are accessible.

For the present invention and in the following examples, the structures of the liquid crystal compounds are indicated by acronyms, wherein the transformation into chemical formulas according to the following Tables A to C takes place. All radicals C _n H _{2n + I} , C _m H _2m + i and QH21 + 1 or C _n H _2n , C _m H _2m and CiH _2I are straight-chain alkyl radicals or alkylene radicals in each case with n, m or I C atoms , Table A lists the ring elements of the cores of the compound, Table B lists the bridge members, and Table C lists the meanings of the symbols for the left and right end groups of the molecules, respectively. The acronyms are composed of the codes for the ring elements with optional join groups, followed by a first hyphen and the codes for the left end group, as well as a second hyphen and the codes for the right end group. Table D summarizes example structures of compounds with their respective abbreviations.

Table A: Rinq Elements

where n and m are integers and the three dots "..." are placeholders for other abbreviations in this table.

The mixtures according to the invention preferably contain, in addition to the compounds of the formulas I, one or more compounds of the compounds mentioned below.

The following abbreviations are used:

(n, m and z are each independently an integer, preferably 1 to 6)

Table D



















Table E lists chiral dopants which are preferably used in the mixtures according to the invention.

Table E

Compounds selected from the group of compounds of Table E. Table F

(n here means an integer from 1 to 12)

In a preferred embodiment of the present invention, the media according to the invention comprise one or more compounds selected from the group of compounds of Table F.

Example 2.2

Optionally, also various of the mentioned example mixtures can be mixed with one another, whereby similar advantageous results are obtained. In particular, the usually associated increase in the number of mixture components usually leads to an improvement in the storage stability of such mixtures.

Claims

claims

1. Liquid-crystalline medium with negative dielectric anisotropy, which

a) a first dielectric negative component (component A) consisting of one or more compounds of the formula I.

wherein

R ¹¹ and R ^{12 are} each, independently of one another, H, an unsubstituted alkyl or alkenyl radical having up to 15 C atoms, where in these radicals also one or more CH ₂ groups is represented by -O-, -S-,

, -C≡C-, -CF ₂ -O-, -O-CF ₂ -,

-CO-O- or -O-CO- may be replaced so that O atoms are not directly linked to one another,

one of the existing rings

and the others, if any, each independently

Z ¹¹ to Z ^{13 are} each, independently of one another, -CH ₂ -CH ₂ -, -CH = CH-, -C≡C-, -CH ₂ -O-, -O-CH ₂ -, -CO-O-, -O- CO-, -CF ₂ -O-, -O-CF ₂ -, -CF ₂ -CF ₂ - or a single bond,

m and n are each independently 0 or 1 and

mean and

wherein

R ²¹ and R ^{22 are} each independently H, an unsubstituted alkyl or alkenyl radical of up to 15 C atoms, wherejn these radicals also one or more CH ₂ groups by -O-, -S-,

■ -C≡C-, -CF ₂ -O-, -O-CF ₂ -,

one of the existing rings

and the others, if any, each independently

L ²¹ and L ²² independently = C (X ² ) - and one of L ²¹ and L ²² alternatively also = N-,

X 1, F, Cl, OCF ₃ , CF ₃ , CH ₃ , CH ₂ F, CHF ₂ ,

Z 72 "1 to Z 23 each independently of one another -CH ₂ -CH ₂ -, -CH ₂ -CF ₂ -, -CF ₂ -CH ₂ -, -CF ₂ -CF ₂ -, - CH = CH-, -CF = CH-, -CH = CF-, -C≡C-, -CH ₂ -O-, -O-CH ₂ -, -O-, -CH ₂ -, -CO-O-, -O-CO- -CF ₂ -O-, -O-CF ₂ - or a single bond,

and o are each independently O or 1 and. mean, contains.

2. Medium according to claim 1, characterized in that it additionally

wherein

R ³¹ and R ^{32 are} each independently, have one of the meaning given for R ¹¹ and R ¹² , and

each independently

Z ³¹ to Z • 33 are each independently of one another, have one of the meaning given in claim 1 for Z ¹¹ to Z ¹³ and

p and q are each independently, 0 or 1,

mean, contains.

3. Medium according to at least one of claims 1 and 2, characterized in that it comprises one or more compounds selected from the group of compounds of formulas 1-1 to I-4

wherein the parameters have the respective meanings claimed.

4. Medium according to claim 3, characterized in that it contains one or more compounds selected from the group of compounds of formulas 1-1 to I-4 according to claim 3, wherein

each independently

O

of the

mean.

5. Medium according to claim 4, characterized in that it comprises one or more compounds selected from the group of the compounds of formulas 1-1 a to l-4a

wherein the parameters have the meaning given in claim 1.

6. Medium according to at least one of claims 1 to 5, characterized in that it comprises one or more compounds selected from the group of compounds of formulas 11-1 to II-5

wherein

R ²¹ and R ^{22 have} the meaning given in claim 1 and

X ²² to X ²⁶ independently of one another H or F, and

one of X ²⁷ and X ²⁸ H and the other H or F,

mean, contains.

7. Medium according to claim 6, characterized in that it contains one or more compounds of the formulas II-2.

8. Medium according to one or more of claims 1 to 7, characterized in that it additionally d) a further dielectrically negative component (component D) which consists of one or more compounds selected from the group of the compounds of the formulas IV and V.

wherein

R ⁴¹ and R ⁴² , R ⁵¹ and R ^{52 are} each independently H, an unsubstituted alkyl or alkenyl radical having up to 15 carbon atoms, wherein in these radicals also one or more

CH ₂ groups by -O-, -S-,

■ -C≡C-, -CF ₂ -O-,

-0-CF ₂ -, -CO-O- or -O-CO- may be replaced so that O atoms are not directly linked to each other,

one of the existing rings

L ⁴¹ and L ⁴² independently = C (X ⁴ ) - and one of L ⁴¹ and L alternatively also = N-, where

X ⁴ F, Cl, OCF ₃ , CF ₃ , CH ₃ , CH ₂ F, CHF ₂ , and the other rings, if any, each independently

one of the rings

and the others, if any, each independently

together optionally also a single bond,

Z ⁴¹ to Z ⁴³ and Z ⁵¹ to Z ^{53 are} each independently of one another, have one of the meaning given for Z ¹¹ to Z 13, and

r and s are each independently 0 or 1,

t and u are each independently, 0 or 1,

mean, wherein the compounds of formula II are excluded from the compounds of formula IV contains.

9. Medium according to one or more of claims 1 to 8, characterized in that it additionally

e) contains a chiral component (component E) consisting of one or more chiral compounds.

10. Medium according to one or more of claims 1 to 9, characterized in that the proportion of compounds of formula I in the total mixture is 15 wt .-% or more.

11. Medium according to one or more of claims 1 to 10, characterized in that the proportion of compounds of the formulas 1-1 to I-4 as defined in claim 7 in the total mixture is 20% by weight or more.

12. Medium according to one or more of claims 8 to 11, characterized in that it

2-80% by weight of one or more compounds of the formula I,

2-80% by weight of one or more compounds of the formula II,

2-80 wt .-% of one or more compounds of formula III and / or

2-80 wt .-% of one or more compounds of the formulas IV and / or V.

contains, wherein the total content of all compounds of formulas I to V in the medium is 100 wt .-% or less.

13. Electro-optical display characterized in that it contains as a dielectric liquid-crystalline medium according to one or more of claims 1 to 12.

14. A display according to claim 13, characterized in that it comprises an active matrix addressing device.

15. Display according to at least one of claim 13 or 14, characterized in that it is based on the VA, ECB, PALC, FFS or the IPS effect.

16. Use of a liquid-crystalline medium according to one or more of claims 1 to 12 in an electro-optical display.

17. Use of a liquid-crystalline medium according to claim 16 in an electro-optical display comprising an active matrix addressing device.

18. A process for the preparation of a medium according to one or more of claims 1 to 12, characterized in that one or more compounds of formula I, as given in claim 1, with one or more compounds of formula II, as given in claim 1, and / or with one or more of the compounds mentioned in one or more of claims 2 to 3 and 7 and / or one or more further liquid-crystalline compounds and / or one or more additives.