DE102011013007A1 - Liquid crystalline medium with a nematic phase and a negative dielectric anisotropy, useful in electro-optical displays or components, comprises a substituted cyclic compound and a compound comprising substituted piperidine structural unit - Google Patents

Abstract

Liquid crystalline medium with a nematic phase and a negative dielectric anisotropy, comprises: (a) at least one substituted cyclic compound (I); and (b) at least one compound comprising at least one substituted piperidine structural unit (IIa) (upto 1 wt.%). Liquid crystalline medium with a nematic phase and a negative dielectric anisotropy, comprises: (a) at least one substituted cyclic compound of formula (I); and (b) at least one compound comprising at least one substituted piperidine structural unit of partial formula (IIa) (upto 1 wt.%). R 1>1>, R 1>2>upto 15C alkyl or upto 15C alkenyl (both unsubstituted) (where at least one CH 2group may be replaced by -O-, cyclobutane-1,3-diyl, -CC-, -CF 2-O-, -O-CF 2-, -CO-O- or -O-CO-, in which O atoms are not directly linked with each other, and at least one H may be replaced by halo); A 1>1>-A 1>3>substituted cyclohexane-1,4-diyl moiety of formula (Ia) or (Ib), cyclohexane-1,4-diyl, 2-fluoro-cyclohexene-1,4-diyl, cyclohexene-1,4-diyl, cyclohexene-3,6-diyl, [1,3]dioxane-2,5-diyl, tetrahydropyran-2,5-diyl, benzene-1,4-diyl, 2-fluoro-benzene-1,4-diyl or 2,3-difluoro-benzene-1,4-diyl (where A 1>1>, A 1>2>and A 1>3>are not equal); Y 1>halo; Z 1>1>, Z 1>2>-CH 2-CH 2-, -CH 2-CF 2-, -CF 2-CH 2-, -CF 2-CF 2-, -CH=CH-, -CF=CH-, -CH=CF-, -CF=CF-, -CC-, -CH 2-O-, -O-CH 2-, -O-, -CH 2-, -CO-O-, -O-CO-, -CF 2-O-, -O-CF 2- or single bond; n : 0 or 1; and R 2>1>-R 2>5>upto 15C alkyl or upto 15C alkenyl (both unsubstituted) (where at least one CH 2group may be replaced by -O-, -S-, cyclobutane-1,3-diyl, -CC-, -CF 2-O-, -O-CF 2-, -CO-O- or -O-CO-, in which O atoms are not directly linked with each other) or H. Independent claims are also included for: (1) an electro-optical display or an electro-optical component comprising the above liquid crystalline medium; (2) producing the liquid crystalline medium, comprising mixing at least one compound (I) with at least one compound (II); and (3) stabilizing the liquid crystalline medium, which comprises at least one compound (I), comprising adding at least one compound comprising 2,2,6,6-tetramethyl-piperidine derivative of formulae (II-1)-(II-7) into the medium. [Image] [Image] [Image] [Image] [Image].

Description

The present invention relates to liquid crystal media and their use in liquid crystal displays, as well as these liquid crystal displays, particularly liquid crystal displays, which use the ECB (Electrically Controlled Birefringence) effect with dielectrically negative liquid crystals in a homeotropic home orientation. The liquid-crystal media according to the invention are characterized by a particularly low switching time in the displays according to the invention with simultaneously high voltage holding capacity (English "voltage holding ratio", short VHR).

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", Appl. Phys. Lett. 19 (1971), 3912 ). It was followed by works by JF Kahn (Appl Phys Lett 20 (1972), 1193) and G. Labrunie and J. Robert (J. Appl. Phys. 44 (1973), 4869) ,

The works 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 ₃ / K ₁ , high values for the optical anisotropy Δn and values for the dielectric anisotropy Δε ≦ -0.5, for high information 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 DC and AC 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 LC phases.

Matrix liquid crystal displays (MFK displays) are known. For example, active elements (i.e., transistors) may be used as nonlinear 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 made of compound semiconductors such as. B. CdSe or TFT's 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 counter electrode. 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 to fully color-capable image representations, wherein a mosaic of red, green and blue filters is arranged such that each one filter element is opposite to 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 TN cells are used, and for note books, laptop tops and, for mobile applications, mostly TN cells Find.

The term MFK displays here includes any matrix display with integrated non-linear elements, ie. H. in addition to the active matrix also 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 displays with high information density z. B. in automotive or aircraft. In addition to problems with regard to the angle dependence of the contrast and the switching times, difficulties arise in the case of MFK displays due to the insufficiently high specific resistance of the liquid-crystal mixtures [ TOGASHI, S., SEKIGUCHI, K., TANABE, H., YAMAMOTO, E., SORIMACHI, K., TAJIMA, E., WATANABE, H., SHIMIZU, H., Proc. Eurodisplay 84, Sept. 1984: A 210-288 Matrix LCD Controlled by Double Stage Diode Rings, p. 141 ff, Paris ; STROMER, M., Proc. Eurodisplay 84, Sept. 1984: Design of 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 a 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.

Ads that use the ECB effect have become known as VAN (Vertically Aligned Nematic) ads in addition to IPS (In Plane Switching) ads (for example: 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, as one of the three most important recent types of liquid crystal displays, especially for television applications.

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 ...", SID 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, for example: 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 z. 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 , compared. Although the switching times of modern ECB displays have already been significantly improved by control methods with overdrive (overdrive), eg. B .: 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 videotauglichen switching times, especially when switching grayscale is still an unsatisfactory 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.

worin m eine ganze Zahl und n 0 oder 1 bedeuten, enthalten, sind z. B. aus WO 2004/048500 A1 bekannt. Diese Medien können gemäß der dortigen Offenbarung optional auch Stabilisatoren verschiedener Arten, wie z. B. Phenole und sterisch gehinderte Amine (Englisch: hindered amine light stabilizers, kurz: HALS) enthalten. Diese Medien sind jedoch durch relativ hohe Schwellenspannungen und durch bestenfalls moderate Stabilitäten gekennzeichnet. Insbesondere sinkt deren „Voltage Holding Ratio” nach Belastung. Außerdem tritt oft eine gelbliche Verfärbung auf. Nematic liquid crystal mixtures with negative dielectric anisotropy, the laterally fluorinated indane derivatives of the formula

wherein m is an integer and n is 0 or 1, z. B. off WO 2004/048500 A1 known. These media can according to the local disclosure optionally also stabilizers of various types, such as. As phenols and hindered amines (English: hindered amine light stabilizers, short: HALS) included. However, these media are characterized by relatively high threshold voltages and, at best, moderate stabilities. In particular, their "Voltage Holding Ratio" decreases after exposure. In addition, often yellowish discoloration occurs.

The use of various stabilizers in liquid crystalline media is exemplified by JP (S) 55-023169 (A) . JP (H) 05-117324 (A) . WO 02/18515 A1 and JP (H) 09-291282 (A) described.

Compounds having an axially substituted by halogen (F) cycloheylene ring include DE 197 14 231 . DE 187 23 275 . DE 198 31 712 and DE 199 45 890 known. Also in Kirsch, P., Reiffenrath, V. and Bremer, M., Molecular Design and Synthesis, Synlett 1999 (4), 389 et seq. . Kirsch, P. and Tarumi, K. Angew. Chem. Int. Ed., 1997 (37), 484 et seq , and Kirsch, P., Heckmeier, M. and Tarumi, K., Liquid Crystals, 1999 (26), 449 et seq , appropriate connections are mentioned. However, liquid crystalline media containing such compounds are not sufficiently stable, especially for many demanding applications. In particular, decomposition may occur at elevated temperatures. But even under UV exposure often cause problems. Here, in particular, an undesirable, sharp decrease in the voltage holding capacity (the so-called "voltage holding ratio", in short VHR or HR) can be observed.

The stabilization of liquid crystal mixtures containing corresponding compounds by addition of compounds having a pyridin-5-yl moiety is disclosed in U.S. Pat DE 100 50 880 proposed. However, as explained in more detail below, this often does not lead to sufficient stability.

The liquid crystal media of the prior art with correspondingly low drive voltages have relatively low electrical resistances or a low VHR and often result in undesired "flicker" and / or insufficient transmission in the displays. In addition, they are not sufficiently stable against temperature and / or UV exposure, at least when they have a correspondingly high polarity, as is necessary for low drive voltages.

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.

The switching times of the liquid crystal media in the displays must be improved, ie reduced. This is especially important for ads for TV 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 ₁ ), 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.

Especially important is a sufficient stability of the media against extreme loads, especially against temperature stress. Especially for applications in ads in mobile devices such. As mobile phones, this can be crucial.

The disadvantage of the previously known MFK displays is their comparatively low contrast, the relatively high viewing angle dependency and the difficulty in creating gray levels in these displays, as well as their insufficient VHR and their inadequate service 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 levels of gray and in particular have a good and stable VHR.

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 been found that liquid crystal displays can be realized which, in particular in ECB displays, have a low threshold voltage with short switching times and at the same time a sufficiently broad nematic phase, favorable low birefringence (Δn), good thermal decomposition stability and a stable high VHR when nematic liquid-crystal mixtures containing at least one compound of the formula I and at least one compound containing one or more groups of the partial formula IIa are used in these display elements.

Such media are to be used in particular for electro-optical displays with an active-matrix addressing based on the ECB effect as well as for in-plane switching (IPS) displays.

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 which contains a group of the partial formula IIa.

The mixtures according to the invention show very broad nematic phase ranges with clearing points ≥ 70 ° C., very favorable values for the capacitive threshold, relatively high values for the holding ratio and at the same time good low-temperature stabilities at -20 ° C. and -30 ° 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.

• a) eine oder mehrere Verbindungen der Formel I
  
  worin R¹¹ und R¹² unabhängig voneinander einen unsubstituierten Alkyl- oder Alkenylrest mit bis zu 15 C-Atomen, wobei in diesen Resten auch eine oder mehrere CH₂-Gruen durch -O-, -S-,
  
  pp-C≡C-, -CF₂-O-, -O-CF₂-, -CO-O- oder -O-CO- so ersetzt sein können, dass O-Atome nicht direkt miteinander verknüpft sind, wobei in allen Gruppen eine oder mehrere H-Atome durch Halogenatome ersetzt sein können, bevorzugt Alkyl, Alkoxy, Oxaaylky oder Alkenyl, besonders bevorzugt Alkyl oder Alkenyl und einer der vorhandenen Ringe
  
  
  
  Y¹ Halogen, bevorzugt Cl oder F, besonders bevorzugt F, Z¹¹ und Z¹² jeweils unabhängig voneinander -CH₂-CH₂-, -CH₂-CF₂-, -CF₂-CH₂-, -CF₂-CF₂-, -CH=CH-, -CF=CH-, -CH=CF-, -CF=CF-, -C=C-, -CH₂-O-, -O-CH₂-, -O-, -CH₂-, -CO-O-, -O-CO-, -CF₂-O-, -O-CF₂- oder eine Einfachbindung, bevorzugt -CH₂-CH₂- oder eine Einfachbindung, besonders bevorzugt eine Einfachbindung und n 0 oder 1 bedeuten, und
• b) bis zu 1,0%, bevorzugt bis zu 0,50%, besonders bevorzugt bis zu 0,10%, einer oder mehrerer Verbindungen, die ein oder mehrere Strukturelemente der Teilformel IIa enthalten,
  
  worin R²¹ bis R²⁵ jeweils unabhängig voneinander H, einen unsubstituierten Alkyl- oder Alkenylrest mit bis zu 15 C-Atomen, wobei in diesen Resten auch eine oder mehrere CH2-Gruppen durch -O-, -S-,
  
  -C≡C-, -CF₂-O-, -O-CF₂-, -CO-O- oder -O-CO- so ersetzt sein können, dass O-Atome nicht direkt miteinander verknüpft sind, bevorzugt R²¹ bis R²⁴ jeweils unabhängig voneinander Alkyl, besonders bevorzugt Methyl, und R²⁵ H, Alkyl oder Alkoxy, bevorzugt H, Methyl oder n-Oktyloxy, besonders bevorzugt H, bedeuten, enthält.

The invention thus relates to a liquid-crystalline medium having a nematic phase and a negative dielectric anisotropy, which

• a) one or more compounds of the formula I.
  
  in which R ¹¹ and R ¹² independently of one another represent an unsubstituted alkyl or alkenyl radical having up to 15 C atoms, in which radicals also one or more CH ₂ -Gruen by -O-, -S-,
  
  pp-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, wherein in all Groups one or more H atoms may be replaced by halogen atoms, preferably alkyl, alkoxy, Oxaaylky or alkenyl, more preferably alkyl or alkenyl and one of the existing rings
  
  
  
  Y ^{1 is} halogen, preferably Cl or F, more preferably F, Z ¹¹ and Z ^{12 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-, -CF = 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 - or a single bond, more preferably one Single bond and n denote 0 or 1, and
• b) up to 1.0%, preferably up to 0.50%, more preferably up to 0.10%, of one or more compounds containing one or more structural elements of the partial formula IIa,
  
  in which R ²¹ to R ^{25 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 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 R ²¹ to R ^{24 are} each independently of one another alkyl, particularly preferably methyl, and R ^{25 is} H, alkyl or alkoxy, preferably H, methyl or n-octyloxy, particularly preferably H.

The medium according to the invention preferably contains one or more compounds which contain one or more structural elements of sub-formula IIa, preferably in a total concentration in the range of 5, ^{0x10 -4} % or more, preferably ^{1.0x10 -3} % or more, more preferably ^{1.0x10 -3} % or more, 0.5% or less, preferably 0.2% or less, more preferably 0.1% or less.

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.

The total concentration of the compounds of the formula I in the media according to the invention is preferably 2% or more to 70% or less, more preferably 3% or more to 40% or less.

worin die Parameter die jeweiligen oben bei Formel I gegeben Bedeutungen haben und bevorzugt
R¹¹ und R¹² Alkyl, Alkoxy, Oxaaylky oder Alkenyl, besonders bevorzugt Alkyl oder Alkenyl, bevorzugt beide Alkyl oder einer von beiden Alkyl und der andere Alkenyl und, ganz besonders bevorzugt, beide Alkenyl, und
Y¹ Cl oder F, bevorzugt F
bedeuten.Preferred compounds of the formula I are the compounds selected from the group of the compounds of the formulas I-1 to I-8, preferably selected from the group of the compounds of the formulas I-1, I-2, I-4, I-5 and I. -8, particularly preferably selected from the group of the compounds of the formulas I-1, I-4 and I-8, very particularly preferably of the formula I-1,

wherein the parameters have the respective meanings given above for formula I and preferably
R ¹¹ and R ^{12 are} alkyl, alkoxy, oxaaylky or alkenyl, particularly preferably alkyl or alkenyl, preferably both alkyl or one of both alkyl and the other alkenyl and, most preferably, both alkenyl, and
Y ¹ Cl or F, preferably F
mean.

worin
R²¹ bis R²⁵ die oben bei Teilformel IIa gegeben Bedeutungen haben und
Z²¹ -O-, -CO-, -CO-O-, -O-CO- oder eine Einfachbindung, bevorzugt -CO-O-,
Sp²¹ -[CH₂]_p- oder eine Einfachbindung, bevorzugt eine Einfachbindung,
p eine ganze Zahl von 1 bis 16, bevorzugt von 1 bis 12
m 1, 2, 3 oder 4, und

R²⁶ einen unsubstituierten Alkyl- oder Alkenylrest mit bis zu 15 C-Atomen, wobei in diesen Resten auch eine oder mehrere CH₂-Gruppen durch -O-, -S-,

-C≡C-, -CF₂-O-, -O-CF₂-, -CO-O- oder -O-CO- so ersetzt sein können, dass O-Atome nicht direkt miteinander verknüpft sind,
Sp²² -[CH₂]_o- oder eine Einfachbindung, bevorzugt -[CH₂]_o,
o eine ganze Zahl von 1 bis 16, bevorzugt von 1 bis 12, besonders bevorzugt 6 oder 8,
Z²² -CH₂-CH₂-, -CH₂-CF₂-, -CF₂-CH₂-, -CF₂-CF₂-, -CH=CH-, -CF=CH-, -CH=CF-, -CF=CF-, -C≡C-, -CH₂-O-, -O-CH₂-, -CO-O-, -O-CO-, -CF₂-O-, -O-CF₂- oder eine Einfachbindung, bevorzugt -CH₂-CH₂- oder eine Einfachbindung, besonders bevorzugt eine Einfachbindung,

Preferred compounds containing one or more structural elements of sub-formula IIa are the compounds of formula II

wherein
R ²¹ to R ^{25 have} the meanings given above in Partial Formula IIa, and
Z ^{21 is} -O-, -CO-, -CO-O-, -O-CO- or a single bond, preferably -CO-O-,
Sp ²¹ - [CH ₂ ] _p - or a single bond, preferably a single bond,
p is an integer from 1 to 16, preferably from 1 to 12
m is 1, 2, 3 or 4, and

R ^{26 is} an unsubstituted alkyl or alkenyl radical having up to 15 C atoms, where in these radicals also one or more CH ₂ groups is 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 to each other,
Sp ²² - [CH ₂ ] _o - or a single bond, preferably - [CH ₂ ] _o ,
o is an integer from 1 to 16, preferably from 1 to 12, particularly preferably 6 or 8,
Z ^{22 is} -CH ₂ -CH ₂ -, -CH ₂ -CF ₂ -, -CF ₂ -CH ₂ -, -CF ₂ -CF ₂ -, -CH = CH-, -CF = CH-, -CH = CF -, -CF = CF-, -C≡C-, -CH ₂ -O-, -O-CH ₂ -, -CO-O-, -O-CO-, -CF ₂ -O-, -O- CF ₂ - or a single bond, preferably -CH ₂ -CH ₂ - or a single bond, more preferably a single bond,

worin die Parameter die jeweiligen oben unter Formel II gegebenen Bedeutungen besitzen und bevorzugt
R²⁵ H, einen unsubstituierten Alkyl- oder Alkoxyrest und
R²⁶ einen unsubstituierten Alkylrest,
bedeuten.The media according to the invention preferably comprise one or more compounds of the formula II, preferably one or more compounds selected from the group of the compounds of the formulas II-1 to II-7, preferably selected from the group of the compounds of the formulas II-3 and II-4 and very particularly preferably the formula II-3,

wherein the parameters have the respective meanings given above under formula II and preferred
R ²⁵ H, an unsubstituted alkyl or alkoxy radical and
R ^{26 is} an unsubstituted alkyl radical,
mean.

The media according to the invention very preferably comprise one or more compounds of the formula II selected from the group of the compounds of the formulas II-1a, I-1b, II-2a and II-2b, II-3a to II-3c, II-5a, II 5b, II-6a, II-6b, II-7a and II-7b, preferably selected from the group of compounds of the formulas II-3a, II-3b and II-3c, and very particularly preferably of the formula II-3a,

worin
R³¹ und R³² jeweils unabhängig voneinander, eine der für R¹¹ und R¹² gegebenen Bedeutung haben und bevorzugt Alkyl mit 1 bis 7 C-Atomen, bevorzugt n-Alkyl, besonders bevorzugt n-Alkyl mit 1 bis 5 C-Atomen, Alkoxy mit 1 bis 7 C-Atomen, bevorzugt n-Alkoxy, besonders bevorzugt n-Alkoxy mit 2 bis 5 C-Atomen, Alkoxyalkyl, Alkenyl oder Alkenyloxy mit 2 bis 7 C-Atomen, bevorzugt mit 2 bis 4 C-Atomen, bevorzugt Alkenyloxy,

Z³¹ bis Z³³ jeweils unabhängig voneinander, eine der für Z¹¹ bis Z¹³ gegebene Bedeutung haben und bevorzugt -CH₂-CH₂-, -CH=CH-, -C≡C-, -COO- oder eine Einfachbindung, bevorzugt -CH₂-CH₂- oder eine Einfachbindung und besonders bevorzugt eine Einfachbindung,
p und q jeweils unabhängig voneinander, 0 oder 1,
(p + q) bevorzugt 0 oder 1, bevorzugt 0,
bedeuten und gegebenenfalls
eine oder mehrere Verbindungen ausgewählt aus der Gruppe der Verbindungen der Formeln IV und V

worin
R⁴¹, R⁴², R⁵¹ und R⁵² jeweils unabhängig voneinander eine der für R¹¹ und R¹² gegebenen Bedeutung haben und R⁵² alternativ auch H oder F bedeuten kann, und bevorzugt Alkyl mit 1 bis 7 C-Atomen, bevorzugt n-Alkyl und besonders bevorzugt n-Alkyl mit 1 bis 5 C-Atomen, Alkoxy mit 1 bis 7 C-Atomen, bevorzugt n-Alkoxy und besonders bevorzugt n-Alkoxy mit 2 bis 5 C-Atomen oder Alkoxyalkyl, Alkenyl oder Alkenyloxy mit 2 bis 7 C-Atomen, bevorzugt mit 2 bis 4 C-Atomen, bevorzugt Alkenyloxy, besonders bevorzugt einer von R⁴¹ und R⁴², bevorzugt R⁴¹, einen Alkyl- oder Alkenylrest und der andere einen Alkyl-, Alkenyl-, Alkoxy- oder Alkenyloxyrest, besonders bevorzugt R⁴¹ geradkettiges Alkyl, insbesondere CH₃-, C₂H₅-, n-C₃H₇, n-C₄H₉- oder n-C₅H₁₁-, oder Alkenyl, insbesondere CH₂=CH-, E-CH₃-CH=CH-, CH₂=CH-CH₂-CH₂-, E-CH₃-CH=CH-CH₂-CH₂- oder E-n-C₃H₇-CH=CH-,
einer der vorhandenen Ringe

L⁴¹ und L⁴² unabhängig voneinander =C(X⁴)- und einer von L⁴¹ und L⁴² alternativ auch =N-,
X⁴ F, Cl, OCF₃, CF₃, CH₃, CH₂F, CHF₂, bevorzugt F oder Cl, besonders bevorzugt F,
wobei bevorzugt mindestens einer von L⁴¹ und L⁴² =C(-F)- und der andere =C(-F)- oder =C(-Cl)-, besonders bevorzugt L⁴¹ und L⁴² beide =C(-F)-, und die anderen Ringe,

Z⁴¹ bis Z⁴³ und
Z⁵¹ bis Z⁵³ jeweils unabhängig voneinander, eine der für Z¹¹ bis Z¹³ gegebene Bedeutung haben und bevorzugt -CH₂-CH₂-, -CH₂-O-, -CH=CH-, -C≡C-, -COO- oder eine Einfachbindung, bevorzugt -CH₂-CH₂-, -CH₂-O- oder eine Einfachbindung und besonders bevorzugt -CH₂-O- oder eine Einfachbindung,
Z⁴¹ bis Z⁴³ bevorzugt jeweils unabhängig voneinander -CH₂-CH₂-, -CH₂-CF₂-, -CF₂-CH₂-, -CF₂-CF₂-,- CH=CH-, -CF=CH-, -CH=CF-, -C≡C-, -CH₂-O-, -O-CH₂-, -O-, -CH₂-, -CO-O-, -O-CO-, -CF₂-O-, -O-CF₂- oder eine Einfachbindung, bevorzugt -CH₂-CH₂-, -CH=CH-, -C≡C-, -CF₂-O-, -O-CF₂- oder eine Einfachbindung, besonders bevorzugt einer oder, soweit vorhanden, mehrere von Z⁴¹ bis Z⁴³ eine Einfachbindung, und ganz besonders bevorzugt alle eine Einfachbindung,
r und s jeweils unabhängig voneinander 0 oder 1,
(r + s) bevorzugt 0 oder 1,
t und u jeweils unabhängig voneinander, 0 oder 1,
(t + u) bevorzugt 0 oder 1, bevorzugt 0,
bedeuten, wobei die Verbindungen der Formel I bei den Verbindungen der Formel V sind, und gegebenenfalls eine oder mehrere chirale Verbindungen.In a preferred embodiment, the media according to the invention comprise one or more compounds of the formula III

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

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
one or more compounds selected from the group of compounds of the formulas IV and V.

wherein
R ⁴¹ , R ⁴² , R ⁵¹ and R ⁵² each independently have one of the meanings given for R ¹¹ and R ¹² and R ^{52 can} alternatively also denote H or F, and preferably alkyl having 1 to 7 C atoms, preferably n- Alkyl and particularly preferably n-alkyl having 1 to 5 carbon atoms, alkoxy having 1 to 7 carbon atoms, preferably n-alkoxy and particularly preferably n-alkoxy having 2 to 5 carbon atoms or alkoxyalkyl, alkenyl or alkenyloxy with 2 to 7 C atoms, preferably having 2 to 4 C atoms, preferably alkenyloxy, more 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 ^{41 is} straight-chain alkyl, in particular CH ₃ -, C ₂ H ₅ -, nC ₃ H ₇ , nC ₄ H ₉ - or nC ₅ H ₁₁ -, 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 EnC 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 = N-,
X ⁴ F, Cl, OCF ₃ , CF ₃ , CH ₃ , CH ₂ F, CHF ₂ , preferably F or Cl, particularly preferably F,
wherein preferably at least one of L ⁴¹ and L ⁴² = C (-F) - and the other = C (-F) - or = C (-Cl) -, particularly preferably L ⁴¹ and L ⁴² both = C (-F) -, and the other rings,

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,
Each of Z ⁴¹ to Z ⁴³ is 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 ⁴¹ to Z ⁴³ 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,
where the compounds of the formula I are the compounds of the formula V, and optionally one or more chiral compounds.

The media according to the invention preferably contain the following compounds in the indicated total concentrations
10-60 wt .-% of one or more compounds of formula III and / or
30-80% by weight of one or more compounds of the formulas IV and / or V
wherein the total content of all compounds in the medium is 100%.

The present invention also provides electro-optical displays or electro-optical components which contain liquid-crystalline media according to the invention. Preference is given to electro-optical displays which are based on the VA or the ECB effect and in particular those which are activated by means of an active matrix addressing device.

Accordingly, the use of a liquid-crystalline medium according to the invention in an electro-optical display or in an electro-optical component is likewise an object of the present invention, as is a method for producing the liquid-crystalline media according to the invention, characterized in that one or more compounds of the formula I with one or more compounds containing one or more groups of the partial formulas IIa, preferably with one or more compounds of the formula II, with one or more further compounds, preferably selected from the group of the compounds of the formulas III and IV and / or V.

In addition, the present invention relates to a method for stabilizing a liquid-crystalline medium containing one or more compounds of formula I, characterized in that the medium one or more compounds containing one or more groups of the sub-formulas IIa, preferably one or more compounds of Formula II, to be added.

wobei ganz besonders bevorzugt zwei benachbarte Ringe direkt verknüpft sind und zwar bevorzugt

bedeuten, wobei bei dem Phenylenring ein oder mehrere H-Atome, unabhängig voneinander durch F oder CN, bevorzugt durch F und eine oder zwei nicht benachbarte CH₂-Gruppen des Cyclohexylenrings bzw. eines der beiden Cyclohexylenringe durch O-Atome ersetzt sein können.In a further preferred embodiment, the medium contains one or more compounds of the formula III in which at least two of the rings

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.

worin die Parameter die jeweilige oben bei Formel III angegebene Bedeutung haben und
Y³ H oder F bedeutet und bevorzugt
R³¹ Alkyl oder Alkenyl und
R³² Alkyl, Alkenyl oder Alkoxy, bevorzugt Alkyl oder Alkenyl, besonders bevorzugt Alkenyl,
bedeuten.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-11, preferably selected from the group of the compounds of the formulas III-1 to III-9, preferably from Group III-1 to III-6 and more preferably from group III-1 and III-4,

wherein the parameters have the meaning given above for formula III and
Y ^{3 is} H or F and preferably
R ^{31 is} alkyl or alkenyl and
R ^{32 is} alkyl, alkenyl or alkoxy, preferably alkyl or alkenyl, particularly preferably alkenyl,
mean.

• – der Formeln III-1c, insbesondere bevorzugt
• – der Formel III-1 in der R³¹ Vinyl oder 1-Propenyl und R³² Alkyl, bevorzugt n-Alkyl, besonders bevorzugt R³¹ Vinyl und R³² Propyl bedeuten und
• – der Formeln III-1d, insbesondere bevorzugt
• – der Formel III-1 in der R³¹ und R³² unabhängig voneinander Vinyl oder 1-Propenyl, bevorzugt und R³¹ Vinyl und besonders bevorzugt R³¹ und R³² Vinyl bedeuten.

Particularly preferably, the medium contains one or more compound (s) of the formula III-1 selected from the group

• - of the formulas III-1c, particularly preferred
• - of the formula III-1 in which R ^{31 is} vinyl or 1-propenyl and R ^{32 is} alkyl, preferably n-alkyl, particularly preferably R ^{31 is} vinyl and R ^{32 is} propyl and
• - of the formulas III-1d, particularly preferred
• - The formula III-1 in the R ³¹ and R ^{32 are} independently vinyl or 1-propenyl, preferably and R ^{31 is} vinyl and more preferably R ³¹ and R ^{32 is} vinyl.

worin
Alkyl und Alkyl' unabhängig voneinander Alkyl mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen
Alkoxy Alkoxy mit 1 bis 5 C-Atomen, bevorzugt mit 2 bis 4 C-Atomen und
Alkenyl und Alkenyl' unabhängig voneinander, Alkenyl mit 2 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen bedeuten.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-1a to III-1e, preferably of the formulas III-1a and / or formulas III-1c and / or III-1d, particularly preferably of the formulas III-1c and / or III-1d and very particularly preferably of the formula III-1c and of the formula III-1d,

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 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.

worin
n 3, 4 oder 5 und R^e H oder CH₃
bedeuten.The medium according to the invention particularly preferably comprises 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-1c '

wherein
n is 3, 4 or 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 III-1a and III-1b, preferably of the formulas III-1a and / or III-1b, more preferably the Formula III-1a. 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 several alkenyl end groups, that is to say preferably no compounds of the formulas III-1c to III-1e. 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.

worin
Alkyl und Alkyl' unabhängig voneinander Alkyl mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen,
Alkoxy Alkoxy mit 1 bis 5 C-Atomen, bevorzugt mit 2 bis 4 C-Atomen und
Alkenyl Alkenyl mit 2 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen bedeuten.In a further preferred embodiment, the medium contains one or more compounds of the formula III-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, more preferably the Formula III-2b,

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 1 to 5 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.

worin
Alkyl und Alkyl' unabhängig voneinander Alkyl mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen und
Alkenyl Alkenyl mit 2 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen bedeuten.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 alkyl having 1 to 7 carbon atoms, preferably having 2 to 5 carbon atoms and
Alkenyl alkenyl having 2 to 7 carbon atoms, preferably having 2 to 5 carbon atoms.

In this preferred embodiment, the proportion of these biphenyls in the total mixture is preferably 3% or more, especially 5% or more.

worin die Parameter die oben angegebenen Bedeutungen haben.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.

und hiervon insbesondere die der letzten Formel.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.

worin
Alkyl und Alkyl' unabhängig voneinander Alkyl mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen,
Alkoxy Alkoxy mit bis 1 bis 5 C-Atomen, bevorzugt mit 2 bis 4 C-Atomen und
Alkenyl Alkenyl mit 2 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen bedeuten.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 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
Alkenyl alkenyl having 2 to 7 carbon atoms, preferably having 2 to 5 carbon atoms.

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 n-alkyl.

worin
Alkyl und Alkyl' unabhängig voneinander Alkyl mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen
Alkoxy Alkoxy mit bis 1 bis 5 C-Atomen, bevorzugt mit 2 bis 4 C-Atomen und
Alkenyl Alkenyl mit 2 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen bedeuten.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

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 up to 1 to 5 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.

Alkyl und Alkyl' unabhängig voneinander Alkyl mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen,
Alkoxy Alkoxy mit bis 1 bis 5 C-Atomen, bevorzugt mit 2 bis 4 C-Atomen und
Alkenyl Alkenyl mit 2 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen bedeuten.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

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

worin
Alkyl und Alkyl' unabhängig voneinander Alkyl mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen,
Alkoxy Alkoxy mit bis 1 bis 5 C-Atomen, bevorzugt mit 2 bis 4 C-Atomen und
Alkenyl Alkenyl mit 2 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen bedeuten.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 III-6

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

The media according to the invention particularly preferably comprise one or more compounds selected from the compounds of the formulas III-6a, preferably selected from the group of the compounds PGP-2-3, PGP-3-3 and PGP-3-4, and of the 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.

worin
Alkyl und Alkyl' unabhängig voneinander Alkyl mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen bedeuten.In a further preferred embodiment, the medium contains one or more compounds of the formula III-10 selected from the group of the compounds of the formulas III-10a and III-10b

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

worin
Alkyl und Alkyl' unabhängig voneinander Alkyl mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen bedeuten.In a further preferred embodiment, the medium contains one or more compounds of the formula III-11 of the compounds of the formulas III-11a

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

worin
Y⁴¹ bis Y⁴⁶ unabhängig voneinander H oder F, und X⁴¹ und X⁴² beide H oder einer von X⁴¹ und X⁴² H und der andere F,
jedoch bevorzugt höchstens vier, besonders bevorzugt höchstens drei und ganz besonders bevorzugt einer oder zwei, von Y⁴¹ bis Y⁴⁶, X⁴¹ und X⁴² F,
bedeuten und
die übrigen Parameter die jeweilige oben bei Formel IV angegebene Bedeutung haben und bevorzugt
R⁴¹ Alkyl oder Alkenyl und
R⁴² Alkyl, Alkenyl, Alkoxy oder Alkenyloxy, bevorzugt (O)C_vH_2v+1 und
v eine ganze Zahl von 1 bis 6 bedeuten.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-14

wherein
Y ⁴¹ to Y ⁴⁶ independently of one another are H or F, and X ⁴¹ and X ^{42 are} 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
R ^{42 is} alkyl, alkenyl, alkoxy or alkenyloxy, preferably (O) C _v H _{2v + 1} and
v is an integer from 1 to 6.

worin
Alkyl und Alkyl' unabhängig voneinander Alkyl mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen
Alkoxy Alkoxy mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 4 C-Atomen und
Alkenyl Alkenyl mit 2 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen bedeuten. 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-1a to IV-1d, preferably of the formulas IV-1b and / or IV-1d, more preferably the Formula IV-1b,

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.

worin v die oben angegebene Bedeutung hat.Preferred compounds of the formulas IV-1c or IV-1d are the compounds of the following formulas

wherein v has the meaning given above.

worin R⁴¹ die jeweilige oben bei Formel IV angegebene Bedeutung hat.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.

worin
Alkyl und Alkyl' unabhängig voneinander Alkyl mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen
Alkoxy Alkoxy mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 4 C-Atomen und
Alkenyl Alkenyl mit 2 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen bedeuten.In a 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-3b and / or IV-3d, more preferably of the formula IV-3b,

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%.

worin
Alkyl und Alkyl' unabhängig voneinander Alkyl mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen
Alkoxy Alkoxy mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 4 C-Atomen und
Alkenyl Alkenyl mit 2 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen bedeuten.In a further preferred embodiment, the medium contains 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-4a and / or IV-4b, more preferably the Formula IV-4b,

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.

worin v die oben angegebene Bedeutung hat.Preferred compounds of the formulas IV-4c or IV-4d are the compounds of the following formulas

wherein v has the meaning given above.

worin
R⁴¹ die oben angegebene Bedeutung hat und
m und z jeweils unabhängig eine ganze Zahl von 1 bis 6 und
m + z bevorzugt eine ganze Zahl von 1 bis 6 bedeuten.In a further preferred embodiment, the medium contains one or more compounds of the formula IV-4 of the following sub-formula IV-4e

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.

worin
Alkyl und Alkyl' unabhängig voneinander Alkyl mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen
Alkoxy Alkoxy mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 4 C-Atomen und
Alkenyl Alkenyl mit 2 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen bedeuten.In a further preferred embodiment, the medium comprises one or more compounds of the formula IV-5 selected from the group of the compounds of the formulas IV-5a to IV-5d, preferably of the formulas IV-5b and / or IV-5d,

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.

worin v die oben angegebene Bedeutung hat.Preferred compounds of the formulas IV-5c or IV-5d are the compounds of the following formulas

wherein v has the meaning given above.

worin
Alkyl und Alkyl' unabhängig voneinander Alkyl mit 1 bis 7 C-Atomen,
bevorzugt mit 2 bis 5 C-Atomen
Alkoxy Alkoxy mit bis 1 bis 7 C-Atomen, bevorzugt mit 2 bis 4 C-Atomen und
Alkenyl Alkenyl mit 2 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen
bedeuten und/oder der Gruppe der Verbindungen der Formeln IV-6e bis IV-6m

worin
R die oben für R⁴¹ gegebene Bedeutung hat und
m eine ganze Zahl von 1 bis 6 bedeutet.In a further preferred embodiment, the medium contains one or more compounds of the formula IV-6 selected from the group of the compounds of the formulas IV-6a to IV-6d, preferably of the formulas IV-6a and / or IV-6c, more preferably the Formula IV-6a,

wherein
Alkyl and alkyl 'independently of one another alkyl having 1 to 7 C atoms,
preferably with 2 to 5 C 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 IV-6e to IV-6m

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.

worin
Alkyl und Alkyl' unabhängig voneinander Alkyl mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen
Alkoxy Alkoxy mit bis 1 bis 5 C-Atomen, bevorzugt mit 2 bis 4 C-Atomen und
Alkenyl Alkenyl mit 2 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen
bedeuten und/oder der Gruppe der Verbindungen der Formeln IV-7e bis IV-7i

worin.
R die oben für R⁴¹ gegebene Bedeutung hat und
m eine ganze Zahl von 1 bis 6 bedeutet.In a further preferred embodiment, the medium contains one or more compounds of the formula IV-7 selected from the group of the compounds of the formulas IV-7a to IV-7d, preferably of the formulas IV-7a and / or IV-7c, more preferably the Formula IV-7a,

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 up to 1 to 5 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 IV-7e to IV-7i

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.

worin die Parameter die oben angegebenen Bedeutungen haben. 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.

worin die Parameter die oben angegebenen Bedeutungen haben und
bevorzugt
R⁴² C_vH_2v+1 und
v eine ganze Zahl von 1 bis 6 bedeutet.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
prefers
R ⁴² C _v H _{2v + 1} and
v is an integer from 1 to 6.

worin die Parameter die oben angegebenen Bedeutungen haben und bevorzugt
R⁴² C_vH_2v+1 und
v eine ganze Zahl von 1 bis 6 bedeutet.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-10a to IV-10e

wherein the parameters have the meanings given above and preferred
R ⁴² C _v H _{2v + 1} and
v is an integer from 1 to 6.

worin die Parameter die oben angegebenen Bedeutungen haben.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.

worin
Alkyl und Alkyl' unabhängig voneinander Alkyl mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen
Alkoxy Alkoxy mit 1 bis 7 C-Atomen, bevorzugt mit 2 bis 4 C-Atomen und
Alkenyl Alkenyl mit 2 bis 7 C-Atomen, bevorzugt mit 2 bis 5 C-Atomen bedeuten.In a further preferred embodiment, the medium contains one or more compounds of the formula IV-14 selected from the group of the compounds of the formulas IV-14a to IV-14d, preferably of the formulas IV-14a and / or IV-14b, more preferably of the formula Formula IV-14b,

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.

worin die Parameter die jeweilige oben bei Formel V angegebene Bedeutung haben und bevorzugt
R⁵¹ Alkyl oder Alkenyl und
R⁵² Alkyl, Alkenyl, Alkoxy oder Alkenyloxy bedeuten, In einer weiteren bevorzugten Ausführungsform enthält das Medium (zusätzlich) eine oder mehrere Verbindungen die eine fluorierte Phenanthren-Einheit aufweisen, bevorzugt Verbindungen der Formel V, bevorzugt ausgewählt aus der Gruppe der Verbindungen der Formeln V-9 und V-10

worin die Parameter die jeweilige oben bei Formel V angegebene Bedeutung haben und bevorzugt
R⁵¹ Alkyl oder Alkenyl und
R⁵² Alkyl, Alkenyl, Alkoxy oder Alkenyloxy bedeuten.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 a further preferred embodiment, the medium contains (in addition) one or more compounds which have a fluorinated phenanthrene unit, preferably compounds of the formula V, preferably selected from the group of compounds of the formulas V -9 and V-10

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.

worin die Parameter die jeweilige oben bei Formel V angegebene Bedeutung haben und bevorzugt
R⁵¹ Alkyl oder Alkenyl und
R⁵² Alkyl, Alkenyl, Alkoxy oder Alkenyloxy bedeuten.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 respective meaning given above for formula V and preferred
R ^{51 is} alkyl or alkenyl and
R ^{52 is} alkyl, alkenyl, alkoxy or alkenyloxy.

worin die Parameter die jeweilige oben unter Formel V gegebene Bedeutung haben und bevorzugt
in Formel V-12 und V-13
Z⁵¹ -CH₂-CH₂-, -CH₂-O- oder eine Einfachbindung, bevorzugt -CH₂-O- oder eine Einfachbindung, besonders bevorzugt -CH₂-O-,
in Formel V-14 und V-15
Z⁵¹ -CH₂-CH₂- oder eine Einfachbindung, bevorzugt eine Einfachbindung und
Z⁵² -CH₂-CH₂-, -CH₂-O- oder eine Einfachbindung, bevorzugt -CH₂-O- oder eine Einfachbindung, besonders bevorzugt -CH₂-O
bedeuten.The medium particularly preferably contains (in addition) one or more compounds which have a triple-fluorinated naphthalenediyl unit, preferably compounds of the formula V, preferably selected from the group of the formulas V-12 to V-15

wherein the parameters have the respective meaning given above under formula V and preferably
in Formula V-12 and V-13
Z ^{51 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-,
in Formula V-14 and V-15
Z ⁵¹ -CH ₂ -CH ₂ - or a single bond, preferably a single bond and
Z ^{52 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.

worin die Parameter die oben gegebene Bedeutung besitzen und R⁵¹ bevorzugt Alkyl mit 1 bis 7, bevorzugt mit 1 bis 5, C-Atomen, bevorzugt n-Alkyl und R⁵² bevorzugt Alkoxy mit 1 bis 5, bevorzugt mit 2 bis 4, C-Atomen bedeuten.Very particularly preferred are the following compounds, the compounds of formulas V-12a, V-12b, V-14a and V-14b

wherein the parameters have the meaning given above and R ^{51 is} preferably alkyl having 1 to 7, preferably having 1 to 5, carbon atoms, preferably n-alkyl and R ^{52 is} preferably alkoxy having 1 to 5, preferably 2 to 4, carbon Mean atoms.

worin die Parameter die jeweiligen oben unter Formel V angegebenen Bedeutungen besitzen und besonders bevorzugt
t 0 und
R⁵¹ Alkyl mit 1 bis 7, bevorzugt mit 1 bis 5, C-Atomen, bevorzugt n-Alkyl
bedeutet.In a particularly preferred embodiment of the present invention, the medium contains one or more compounds which have a triple fluorinated indane unit, preferably compounds of the formula V, preferably of the formulas V-16

wherein the parameters have the respective meanings given above under formula V, and particularly preferred
t 0 and
R ^{51 is} alkyl having 1 to 7, preferably having 1 to 5, C atoms, preferably n-alkyl
means.

worin die Parameter die jeweiligen oben unter Formel V-16 angegebenen Bedeutungen besitzen und besonders bevorzugt
t 0 und
R⁵¹ Alkyl mit 1 bis 7, bevorzugt mit 1 bis 5, C-Atomen, bevorzugt n-Alkyl
bedeutet.Particular preference is given here to the compounds of the formula V-16a

wherein the parameters have the respective meanings given above under formula V-16 and are particularly preferred
t 0 and
R ^{51 is} alkyl having 1 to 7, preferably having 1 to 5, C atoms, preferably n-alkyl
means.

worin
R⁶¹ bis R⁶³, R⁷¹ bis R⁷⁵ und R⁸ jeweils unabhängig voneinander, die oben bei Formel I für R¹¹ gegebene Bedeutung besitzen, und alternativ H, CN, F, Cl CF₃, OCF₃, CF₂H oder OCF₂H und mindestens einer von R⁶¹ und R⁶² eine chirale Gruppe bedeuten,
Z⁶¹ und Z⁶², Z⁷¹ bis Z⁷³ und Z⁸ jeweils unabhängig voneinander -CH₂CH₂-, CH=CH-, -COO-, -O-CO- oder eine Einfachbindung, bevorzugt Z⁶¹, Z⁶², Z⁷¹, Z⁷⁴ und Z⁷⁵ eine Einfachbindung, Z⁶³, Z⁷² und Z⁷³ -COO- oder eine Einfachbindung, Z⁷² bevorzugt -COO- und Z⁷³ und Z⁸ -O-CO-,

v, w, x, y und z jeweils unabhängig voneinander, 0 oder 1, bevorzugt
v und w beide 0 und
x und y beide 1,
bedeuten.The chiral compound or chiral compounds which can be used in the liquid crystal media according to the present invention are preferably selected from the known chiral dopants. Component E preferably predominantly, more preferably substantially and very particularly preferably almost completely, consists of one or more compounds selected from the group of the compounds of the following formulas VI to VIII

wherein
R ⁶¹ to R ⁶³ , R ⁷¹ to R ⁷⁵ and R ^{8 are} each independently of one another, have the meaning given above in formula I for R ¹¹ , and alternatively H, CN, F, Cl CF ₃ , OCF ₃ , CF ₂ H or OCF ₂ H and at least one of R ⁶¹ and R ^{62 is} a 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 is} 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-,

v, w, x, y and z are each independently, 0 or 1, preferably
v and w both 0 and
x and y both 1,
mean.

• i. Das flüssigkristalline Medium hat eine Doppelbrechung von 0,060 oder mehr, besonders bevorzugt von 0,070 oder mehr.
• ii. Das flüssigkristalline Medium hat eine Doppelbrechung von 0,120 oder weniger, besonders bevorzugt von 0,110 oder weniger von 0,090 oder weniger.
• iii. Das flüssigkristalline Medium hat eine Doppelbrechung im Bereich von 0,060 oder mehr bis 0,080 oder weniger oder im Bereich von 0,080 oder mehr bis 0,110 oder weniger.
• iv. Das flüssigkristalline Medium enthält eine oder mehrere Verbindungen der Formel I-1.
• v. Die Konzentrationen der einzelnen homologen Verbindungen der Formel 1 liegen im Bereich von 1% bis 20%, bevorzugt von 2% bis 15% und besonders bevorzugt von 3% bis 10%.
• vi. Die Gesamtkonzentration der Verbindungen der Formel II im Gesamtgemisch beträgt 0,1% oder weniger und liegt bevorzugt im Bereich von 0,01% oder mehr bis 0,1% oder weniger.
• vii. Die Konzentrationen der einzelnen homologen Verbindungen der Formel III liegen im Bereich von 2% bis 15%, bevorzugt von 3% bis 12% und besonders bevorzugt von 4% bis 10%.
• viii. Der Anteil an Verbindungen der Formel III im Gesamtgemisch beträgt 10% oder mehr, bevorzugt 70% oder weniger und besonders bevorzugt 20% oder mehr.
• ix. Das flüssigkristalline Medium enthält eine oder mehrere besonders bevorzugte Verbindungen der Formeln III-1c und III-1d ausgewählt aus den nachfolgend genannten den Teilformeln:
  
  worin Alkyl die oben gegebene Bedeutung besitzt und bevorzugt, jeweils unabhängig voneinander Alkyl mit 1 bis 6, bevorzugt mit 2 bis 5 C-Atomen und besonders bevorzugt n-Alkyl, bedeutet.
• x. Das flüssigkristalline Medium enthält eine oder mehrere Verbindungen der Formel III ausgewählt aus der Gruppe der folgenden Formeln
  
  
  worin R³¹ und R³² die oben angegebene Bedeutung haben und bevorzugt R³¹ und R³², jeweils unabhängig voneinander einen geradkettiger Alkyl-, Alkoxy- oder Alkenylrest mit 1 bzw. 2 bis 7 C-Atomen, besonders bevorzugt geradkettiges Alkyl, ferner Alkenyl, bedeuten.

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

• i. The liquid-crystalline medium has a birefringence of 0.060 or more, more preferably 0.070 or more.
• ii. The liquid-crystalline medium has a birefringence of 0.120 or less, more preferably 0.110 or less of 0.090 or less.
• iii. The liquid-crystalline medium has a birefringence in the range of 0.060 or more to 0.080 or less, or in the range of 0.080 or more to 0.110 or less.
• iv. The liquid-crystalline medium contains one or more compounds of the formula I-1.
• v. The concentrations of the individual homologous compounds of the formula 1 are in the range from 1% to 20%, preferably from 2% to 15% and particularly preferably from 3% to 10%.
• vi. The total concentration of the compounds of formula II in the total mixture is 0.1% or less and is preferably in the range of 0.01% or more to 0.1% or less.
• vii. The concentrations of the individual homologous compounds of the formula III are in the range from 2% to 15%, preferably from 3% to 12% and particularly preferably from 4% to 10%.
• viii. The proportion of compounds of the formula III in the total mixture is 10% or more, preferably 70% or less and particularly preferably 20% or more.
• ix. The liquid-crystalline medium contains one or more particularly preferred compounds of the formulas III-1c and III-1d selected from the following sub-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.
• x. The liquid-crystalline medium contains one or more compounds of the formula III selected from the group of the following formulas
  
  
  in which R ³¹ and R ^{32 have} the abovementioned meaning and preferably R ³¹ and R ³² each independently represent a straight-chain alkyl, alkoxy or alkenyl radical having 1 or 2 to 7 C atoms, particularly preferably straight-chain alkyl, furthermore alkenyl, mean.

• xi. Das flüssigkristalline Medium enthält eine oder mehrere Verbindungen der Formel III ausgewählt aus der Gruppe der Verbindungen folgenden Formeln: CC-n-V und/oder CC-n-Vm (z. B. bevorzugt CC-5-V bevorzugt in einer Konzentration von bis zu 25% oder weniger, CC-3-V, bevorzugt in einer Konzentration von bis zu 60% oder weniger und/oder CC-3-V1, bevorzugt in einer Konzentration von bis zu 25% oder weniger und/oder CC-4-V, bevorzugt in einer Konzentration von bis zu 40% oder weniger,) CC-n-m und/oder CC-n-Cm (z. B.: bevorzugt CC-3-2 und/oder CC-3-3 und/oder CC-3-4 und/oder CC-3-O2 und/oder CCP-5-O2), CP-n-m und/oder CP-n-Cm (z. B.: bevorzugt CP-3-2 und/oder CP-5-2 und/oder CP-3-O1 und/oder CP-3-O2), PP-n-Vm (z. B.: bevorzugt PP-n-2V), PP-n-IVm (z. B.: bevorzugt PP-n-2V1), CCP-n-m (z. B. bevorzugt CCP-n-1), CPP-n-m, CGP-n-m und CCOC-n-m, worin die Bedeutung der Akonyme (Abkürzungen) in den Tabellen A bis C erläutert und in Tabelle D durch Beispiele illustriert sind, bevorzugt in einer Gesamtkonzentration von bis zu 10% oder mehr bis 70% oder weniger.
• xii. Das flüssigkristalline Medium besteht im Wesentlichen aus 2% bis 80% einer oder mehrerer Verbindungen der Formel I, 5,0·10^–4% bis 1,0·10^–3% einer oder mehrerer Verbindungen der Formel IIa, 2% bis 80% einer oder mehrerer Verbindungen der Formel III und/oder 2% bis 80% einer oder mehrerer Verbindungen ausgewählt aus der Gruppe der Verbindungen der Formeln IV und/oder V.
• xiii. Das flüssigkristalline Medium enthält eine oder mehrere Verbindungen der Formel IV vorzugsweise in Mengen von 2% oder mehr, insbesondere von 5% oder mehr, und ganz besonders bevorzugt von 5% oder mehr bis 25% oder weniger, insbesondere im Bereich von 2% oder mehr bis 12% oder weniger pro homologer Einzelverbindung.
• xiv. Das flüssigkristalline Medium enthält eine oder mehrere Verbindungen der Formel IV-1 bis IV-3, bevorzugt IV-1 und/oder IV-3, bevorzugt der Formeln IV-1b und/oder IV-1d und/oder IV-3b und/oder IV-3d, besonders bevorzugt IV-1 b und/oder IV-3b, vorzugsweise in einer Gesamtkonzentration von 60% oder weniger und in einer Konzentration von 2% oder mehr, insbesondere von 5% oder mehr, und ganz besonders bevorzugt von 5% oder mehr bis 20% oder weniger pro homologer Einzelverbindung.
• xv. Das flüssigkristalline Medium enthält eine oder mehrere Verbindungen der Formel IV-4 und/oder IV-5, bevorzugt der Formeln IV-4b und/oder IV-4d und/oder IV-5b und/oder IV-5d, besonders bevorzugt IV-4b und/oder IV-5b, vorzugsweise in einer Gesamtkonzentration von 60% oder weniger und in einer Konzentration von 2% oder mehr, insbesondere von 5% oder mehr, und ganz besonders bevorzugt von 5% oder mehr bis 20% oder weniger pro homologer Einzelverbindung.
• xvi. Das flüssigkristalline Medium enthält eine oder mehrere Verbindungen der Formel IV-6 und/oder IV-7, bevorzugt der Formeln IV-6a und/oder IV-7a, vorzugsweise in einer Gesamtkonzentration von 50% oder weniger und bevorzugt in einer Konzentration von 2% oder mehr bis 10% oder weniger pro homologer Einzelverbindung der Formel IV-6 und in einer Konzentration von 2% oder mehr bis 20% oder weniger pro homologer Einzelverbindung der Formel IV-6.
• xvii. Das flüssigkristalline Medium enthält eine oder mehrere Verbindungen der Formel IV vorzugsweise in Mengen von 2% oder mehr, insbesondere von 5% oder mehr, und ganz besonders bevorzugt von 5% bis 25% insbesondere im Bereich von 2% bis 12% pro Einzelverbindung.
• xviii. Das flüssigkristalline Medium enthält eine oder mehrere Verbindungen der Formel V vorzugsweise in Mengen von 3% oder mehr, insbesondere von 5% oder mehr, und ganz besonders bevorzugt von 5% bis 25 %, insbesondere im Bereich von 2% bis 20% pro Einzelverbindung.
• xix. Das flüssigkristalline Medium enthält eine oder mehrere Verbindungen der Formel V-16, bevorzugt der Formel V-16a, vorzugsweise in einer Gesamtkonzentration von 60% oder weniger und in einer Konzentration von 2% oder mehr, insbesondere von 5% oder mehr, und ganz besonders bevorzugt von 5% oder mehr bis 20% oder weniger pro homologer Einzelverbindung.

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

• xi. The liquid-crystalline medium contains one or more compounds of the formula III selected from the group of compounds: CC-nV and / or CC-n-Vm (for example 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 a concentration of up to 40% or less, CC-nm and / or CC-n-Cm (eg: preferably CC-3-2 and / or CC-3-3 and / or CC-3 -4 and / or CC-3-O2 and / or CCP-5-O2), CP-nm and / or CP-n-Cm (for example: preferably CP-3-2 and / or CP-5 2 and / or CP-3-O1 and / or CP-3-O2), PP-n-Vm (for example: preferably PP-n-2V), PP-n-IVm (for example: preferred PP-n-2V1), CCP-nm (eg, preferably CCP-n-1), CPP-nm, CGP-nm, and CCOC-nm, wherein the meaning of the akonymes (abbreviations) is illustrated in Tables A to C. and in Table D are exemplified, preferably in a total con concentration of up to 10% or more to 70% or less.
• xii. The liquid-crystalline medium consists essentially of 2% to 80% of one or more compounds of the formula I, 5.0 · 10 ^-4 % to 1.0 · 10 ^-3 % of one or more compounds of the formula IIa, 2% to 80% one or more compounds of the formula III and / or 2% to 80% of one or more compounds selected from the group of the compounds of the formulas IV and / or V.
• xiii. The liquid-crystalline medium preferably contains one or more compounds of the formula IV 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 compound.
• xiv. The liquid-crystalline medium contains one or more compounds of the formula IV-1 to IV-3, preferably IV-1 and / or IV-3, preferably of the formulas IV-1b and / or IV-1d and / or IV-3b and / or IV-3d, particularly preferably IV-1b and / or IV-3b, preferably in a total concentration of 60% or less and in a concentration of 2% or more, in particular of 5% or more, and very particularly preferably of 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-4 and / or IV-5, preferably of the formulas IV-4b and / or IV-4d and / or IV-5b and / or IV-5d, particularly preferably IV-4b and / or IV-5b, 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 ,
• xvi. The liquid-crystalline medium contains one or more compounds of the formula IV-6 and / or IV-7, preferably of the formulas IV-6a and / or IV-7a, 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 formula IV-6 and in a concentration of 2% or more to 20% or less per homologous single compound of formula IV-6.
• xvii. The liquid-crystalline medium contains one or more compounds of the formula IV, preferably in amounts of 2% or more, in particular of 5% or more, and very particularly preferably of 5% to 25%, in particular in the range of 2% to 12%, per individual compound.
• xviii. The liquid-crystalline medium preferably contains one or more compounds of the formula V 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 individual compound.
• xix. The liquid-crystalline medium contains one or more compounds of the formula V-16, preferably of the formula V-16a, preferably in a total concentration of 60% or less and in a concentration of 2% or more, especially 5% or more, and more particularly preferably from 5% or more to 20% or less per homologous single compound.

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

The liquid-crystal mixture preferably has a nematic phase range with a width of at least 60 degrees and a flow viscosity ν ₂₀ of at most 30 mm ² · s ^-1 at 20 ° C.

The liquid-crystal mixture according to the invention has a Δε of -0.5 to -8.0, in particular of -1.5 to -6.0, and very particularly preferably of -2.0 to -5.0, where Δε is the dielectric Anisotropy means.

The rotational viscosity γ _i 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 0.05 and 0.16, preferably between 0.06 and 0.14.

The mixtures according to the invention are suitable for all VA-TFT applications, such. VAN, MVA, (S) -PVA and ASV. Furthermore, they are suitable for IPS (in-plane 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.

The liquid-crystalline media according to the invention preferably contain 4 to 15, in particular 5 to 12, and particularly preferably 10 or less, compounds. These are preferably selected from the group of the compounds of the formulas I, II-A to II-F, the compounds which contain one or more groups of the partial formula II-G, the formulas and / or III and / or IV and / or V ,

The liquid-crystalline media according to the invention may optionally also contain more than 18 compounds. In this case, they preferably contain 18 to 25 compounds.

In addition to compounds of the formulas I to V and optionally of the formulas Vi to VIII, also other constituents 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, cyclohexylbiphenyls, cyclohexylcyclohexanes, cyclohexylnaphthalenes , 1,4-bis-cyclohexylbiphenyls 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 wherein L and E each ring a carbo- or heterocyclic ring system of the 1,4-disubstituted benzene and cyclohexane, 4,4'-disubstituted biphenyl, phenylcyclohexane and Cyclohexylcyclohexansystemen, 2,5-disubstituted pyrimidine and 1,3 Dioxane rings, 2,6-disubstituted naphthalene, di- and tetrahydronaphthalene, quinazoline and tetrahydroquinazoline, G-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 a CC single bond, Q is halogen, preferably chlorine, or -CN, and R ⁹¹ and R ^{92 are} each alkyl, alkenyl, alkoxy, alkanoyloxy or alkoxy carbonyloxy 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 proposed substituents are common. 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 compounds of formula I 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 compounds of formula III 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 compounds of formulas IV and / or V.

Whereby the respective different preferred ranges of the concentrations of the compounds of the respective different formulas can be combined as desired, but the total concentration of all compounds in the media does not exceed 100% in each case.

In a preferred embodiment, the liquid-crystal media according to the invention comprise compounds selected from the group of the compounds of the formulas I, II-A to II-F, II-G and III to V, preferably they are predominantly, more preferably essentially and very preferably almost completely from the compounds of the formulas mentioned.

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

In this case, the term "having a nematic phase" on the one hand means that no smectic phase and no crystallization is observed at low temperatures at the corresponding temperature and, on the other hand, that no clarification occurs during heating from the nematic phase. The investigation at low temperatures is carried out in a flow viscometer at the appropriate temperature and checked by storage in test cells of a corresponding electro-optical 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 ° C or -40 ° C the corresponding times are 500 h or 250 h. At high temperatures, the clearing point is measured in capillaries by conventional methods.

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 (| Δε |), 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 ) ranging from 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 most 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 average dielectric anisotropy (ε _av. ≡ (ε _|| + 2ε _⊥ ) / 3), which are preferably in the range from 5.0 or more to 7.0 or less, preferably 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 addition, the liquid-crystal media according to the invention have high values for the VHR in liquid-crystal cells.

These are in freshly filled cells at 20 ° 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 ° 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 VHR 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.

• – „enthalten”: die Konzentration der betreffenden Bestandteile in der Zusammensetzung beträgt bevorzugt 5% oder mehr, besonders bevorzugt 10% oder mehr, ganz besonders bevorzugt 20% oder mehr,
• – „überwiegend bestehen aus”: die Konzentration der betreffenden Bestandteile in der Zusammensetzung beträgt bevorzugt 50% oder mehr, besonders bevorzugt 55% oder mehr und ganz besonders bevorzugt 60% oder mehr,
• – „im wesentlichen bestehen aus”: die Konzentration der betreffenden Bestandteile in der Zusammensetzung beträgt bevorzugt 80% oder mehr, besonders bevorzugt 90% oder mehr und ganz besonders bevorzugt 95% oder mehr und
• – „nahezu vollständig bestehen aus”: die Konzentration der betreffenden Bestandteile in der Zusammensetzung beträgt bevorzugt 98% oder mehr, besonders bevorzugt 99% oder mehr und ganz besonders bevorzugt 100,0%.

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,
• "Essentially consist of": the concentration of the constituents in the composition is preferably 80% or more, more preferably 90% or more and most preferably 95% or more and
• "Almost completely composed": the concentration of the constituents in question 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 constituents, which may be components and compounds, as well as to 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

For the present invention, the terms "dielectrically positive compounds" mean those compounds with a Δε> 1.5, "dielectrically neutral compounds" those with -1.5 ≦ Δε ≦ 1.5 and "dielectrically negative" compounds those with Δε <- 1.5. Here, the dielectric anisotropy of the compounds is determined by 10% of the compounds are dissolved in a liquid crystalline host and the capacity of the resulting mixture in at least one test cell with 20 micron layer thickness is determined with homeotropic and 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 liquid crystal mixture under investigation.

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 halved until the investigation 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 usually not taken into account in the indication of the concentrations and the concentration ranges of the liquid crystal compounds in the liquid-crystal media.

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 to use the liquid-crystal mixtures in other usual ways, eg. B. using premixes or from a so-called "multi-bottle system" produce.

The mixtures according to the invention show very broad nematic phase ranges with clearing points of 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 ° C. and -40 ° C. Furthermore, the mixtures according to the invention are distinguished by low rotational viscosities γ ₁ .

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. In EP-OS 0 240 379 , is described. By means of suitable additives, the liquid crystal phases according to the invention can be modified such that they can be used in any type of z. B. ECB, VAN, IPS, GH or ASM-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 may 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 values given for temperatures in the present application, such. B. the melting point T (C, N), the transition from the smectic (S) to the nematic (N) phase T (S, N) and the clearing point T (N, I), are in degrees Celsius (° 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 after "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status Nov. 1997, Merck KGaA, Germany are determined and are valid for a temperature of 20 ° C and Δn is determined at 589 nm and Δε at 1 kHz, unless explicitly stated otherwise.

The electro-optical properties, eg. B. the threshold voltage (V ₀ ) (capacitive measurement), as well as the switching behavior, determined in Merck Japan ^{L td} test cells. 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 VHR is at Merck Japan ^Ltd. determined test cells. The measuring cells have substrates made of sodium glass (sodalime glass) and are made with polyimide orientation layers (AL-3046 from 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 VHR is determined at 20 ° C (VHR ₂₀ ) and after 5 minutes in the oven at 100 ° C (VHR ₁₀₀ ) in a commercially available device from the company Autronic Melchers, Germany. The voltage used has a frequency of 60 Hz.

The accuracy of the VHR readings depends on the value of the VHR. The accuracy decreases with decreasing values.

The deviations observed in values in the various size ranges are usually in their order of magnitude in the following table together. VHR area deviation VHR values (relative)/% from to 95.6% 100% +/- 0.1 99.0% 99.6% +/- 0.2 98% 99% +/- 0.3 95% 98% +/- 0.5 90% 95% +/- 1 80% 95% +/- 2 60% 80% +/- 4 40% 60% +/- 8 20% 40% +/- 10 10% 20% +/- 20

The stability against irradiation with UV is examined in a "Suntest CPS" a commercial device of the company Heraeus, Germany.

The sealed test cells are irradiated for 2.0 hours without additional thermal stress. The irradiation power in the wavelength range from 300 nm to 800 nm is 765 W / m ² V. It is a UV cut-off filter with an edge wavelength of 310 nm used to simulate the so-called window glass mode (English: "window glass mode") , For each test series, at least four test cells are examined for each condition and the respective results are given as mean values of the respective individual measurements.

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 of Merck KGaA, Darmstadt, Germany, the values of the rotational viscosity determined at 20 ° C. are 161 mPa · s, 133 mPa · s and 186 mPa · s, and the viscosity of the fluid (v) 21 mm ² · ^{s -1,} 14 mm ² · ^{s -1} and 27 mm ² · ^{s -1.}

V₀

Schwellenspannung, kapazitiv [V] bei 20°C,

n_e

außerordentlicher Brechungsindex gemessen bei 20°C und 589 nm,

n_o

ordentlicher Brechungsindex gemessen bei 20°C und 589 nm,

Δn

optische Anisotropie gemessen bei 20°C und 589 nm,

ε_⊥

dielektrische Suszeptibilität senkrecht zum Direktor bei 20°C und 1 kHz,

ε_||

dielektrische Suszeptibilität parallel zum Direktor bei 20°C und 1 kHz,

Δε

dielektrische Anisotropie bei 20°C und 1 kHz,

cp. bzw. T(N,I)

Klärpunkt [°C],

γ₁

Rotationsviskosität gemessen bei 20°C [mPa·s],

K₁

elastische Konstante, ”splay”-Deformation bei 20°C [pN],

K₂

elastische Konstante, ”twist”-Deformation bei 20°C [pN],

K₃

elastische Konstante, ”bend”-Deformation bei 20°C [pN] und

LTS

„low temperature stability” (Stabilität der Phase), bestimmt in Testzellen.

The following symbols are used:

V ₀

Threshold voltage, capacitive [V] at 20 ° C,

n _e

extraordinary refractive index measured at 20 ° C and 589 nm,

n _o

ordinary refractive index measured at 20 ° C and 589 nm,

.DELTA.n

optical anisotropy measured at 20 ° C and 589 nm,

ε _⊥

dielectric susceptibility perpendicular to the director at 20 ° C and 1 kHz,

ε _||

dielectric susceptibility parallel to the director at 20 ° C and 1 kHz,

Δε

dielectric anisotropy at 20 ° C and 1 kHz,

cp. or T (N, I)

Clearing point [° C],

γ ₁

Rotational viscosity measured 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, "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.

Tabelle B: Brückenglieder E -CH₂-CH₂- V -CH=CH- T -C≡C- W -CF₂-CF₂- B -CF=CF- Z -CO-O- ZI -O-CO- X -CF=CH- XI -CH=CF- O -CH₂-O- OI -O-CH₂- Q -CF₂-O- QI -O-CF₂- Tabelle C: Endgruppen Links einzelstehend oder in Kombination Rechts einzelstehend oder in Kombination -n- C_nH_2n+1- -n -C_nH_2n+1 -nO- C_nH_2n+1-O -nO -O-C_nH_2n+1 -V- CH₂=CH -V -CH=CH₂ -nV- C_nH_2n+1-CH=CH -nV -C_nH_2n-CH=CH₂ -Vn- CH₂=CH-C_nH_2n -Vn -CH=CH-C_nH_2n+1 -nVm- C_nH_2n+1-CH=CH-C_mH_2m -nVm -C_nH_2n-CH=CH-C_mH_2m+1 -N- N≡C -N -C≡N -S- S=C=N -S -N=C=S -F- F -F -F -CL- Cl -CL -Cl -M- CFH₂- -M -CFH₂ -D- CF₂H -D -CF₂H -T- CF₃- -T -CF₃ -MO- CFH₂O- -OM -OCFH₂ -DO- CF₂HO- -OD -OCF₂H -TO- CF₃O- -OT -OCF₃ -A- H-C≡C -A -C≡C-H -nA- C_nH_2n+1-C≡C -An -C≡C-C_nH_2n+1 -NA- N≡C-C≡C -AN -C≡C-C≡N Links nur in Kombination Rechts nur in Kombination -...n... -C_nH_2n -...n... -C_nH_2n -...M... -CFH -...M... -CFH -...D... -CF₂- -...D... -CF₂- -...V... -CH=CH -...V... -CH=CH -...Z... -CO-C -...Z... -CO-C -..Zl... -O-CO -...Zl... -O-CO -...K... -CO -...K... -CO -...W... -CF=CF -...W... -CF=CF worin n und m jeweils ganze Zahlen und die drei Punkte „...” Platzhalter für andere Abkürzungen aus dieser Tabelle sind.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 + 1} , C _m H _{2m + 1} and C ₁ H _{2l + 1} or C _n H _2n , C _m H _2m and C _l H _2l 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: Ring elements

Table B: Bridge links e -CH ₂ -CH ₂ - V -CH = CH- T -C≡C- W -CF ₂ -CF ₂ - B CF = CF Z -CO-O- ZI -O-CO- X CF = CH- XI -CH = CF- O -CH ₂ -O- OI -O-CH ₂ - Q -CF ₂ -O- QI -O-CF ₂ - Table C: end groups Left alone or in combination Right alone or in combination -n- C _n H _{2n + 1} - -n -C _n H _{2n + 1} -no- C _n H _{2n + 1} -O -NO -OC _n H _{2n + 1} -V- CH ₂ = CH -V -CH = CH ₂ -nV- C _n H _{2n + 1} -CH = CH -nv -C _n H _2n -CH = CH ₂ -Vn- CH ₂ = CH-C _n H _2n Vn -CH = CH-C _n H _{2n + 1} -nVm- C _n H _{2n + 1} -CH = CH-C _m H _2m -nVm -C _n H _2n -CH = CH-C _m H _{2m + 1} -N- N≡C -N -C≡N -S S = C = N -S -N = C = S -F- F -F -F -CL- Cl CL -Cl -M- CFH ₂ - -M -CFH ₂ D- CF ₂ H -D -CF ₂ H -T- CF ₃ - -T -CF ₃ -NOT A WORD- CFH ₂ O- -OM -OCFH ₂ -DO- CF ₂ HO- --OD -OCF ₂ H -to- CF ₃ O- --OT -OCF ₃ -A- HC≡C -A -C≡CH -n / A- C _n H _{2n + 1} -C≡C -At -C≡CC _n H _{2n + 1} -N / A- N≡CC≡C -AT -C≡CC≡N Links only in combination Right only in combination -... n ... -C _n H _2n -... n ... -C _n H _2n -... M ... CFH -... M ... CFH -... D ... -CF ₂ - -... D ... -CF ₂ - -... V ... -CH = CH -... V ... -CH = CH -... Z ... -CO-C -... Z ... -CO-C - .. Zl ... -O-CO -... Zl ... -O-CO -... K ... --CO -... K ... --CO -... W ... CF = CF -... W ... CF = CF 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.

in der Tabelle E werden chirale Dotierstoffe genannt, die bevorzugt in den erfindungsgemäßen Mischungen eingesetzt werden. Tabelle E

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

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

Table F lists stabilizers which are preferably used in the mixtures according to the invention. 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.

Table G lists stabilizers which contain one or more groups of sub-formula IIa, which are preferably used in the mixtures according to the invention. Table G

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

Examples

The following examples illustrate the present invention without limiting it in any way. From the physical properties, however, it will be apparent to those skilled in the art which properties can be achieved and in which areas they are modifiable. In particular, therefore, the combination of the various properties that can preferably be achieved, well defined for the expert.

Comparative Examples 1.0 to 1.2 and Example 1

Comparative Example 1.0

The following mixture (A-1) is prepared and tested. Mixture A-1 composition Physical Properties connection concentration T (N, I) = 77.0 ° C Δn (20 ° C, 589 nm) = 0.0692 Δε (20 °, 1 kHz) = -3.7 γ ₁ (20 ° C) = 150 mPa · s No. abbreviation / Mass% 1 CX-3-4 20.0 2 CY-3-O4 9.6 3 CY-5-O4 9.6 4 CCY-2-O2 9.6 5 CCY-3-O2 9.6 6 CCY-5-O2 6.4 7 CCY-2-1 9.6 8th CCY-3-1 6.4 9 CC-3-4 6.4 10 CP-5-3 12.8 Σ 100.0

The starting mixture A-1 is tested for its decomposition temperature under temperature load with the aid of a DSC device "Q1000" from TA Instruments, USA. In this case, 5 mg are used in a closed Al crucible and a heating rate of 5 degrees / minute. The decomposition temperature results from the first significant deviation from the baseline. Known phase transitions are not taken into account here.

werden der Mischung A-1 zugesetzt. Die resultierende Mischung (V-1.1) wird ebenfalls auf ihre Zersetzungstemperatur untersucht. Das Ergebnis ist auch in Tabelle 1 zum Vergleich aufgenommen. Vergleichsbeispiel 1.2 500 ppm der Verbindung DST

werden der Mischung A-1 zugesetzt. Die resultierende Mischung (V-1.2) wird ebenfalls auf ihre Zersetzungstemperatur untersucht. Das Ergebnis ist auch in Tabelle 1 zum Vergleich aufgenommen.The mixture A-1 is examined as such, without addition of a stabilizer, to its decomposition temperature. The result is included in Table 1 for comparison (Comparative Example 1.0 (= V-1.0)). Comparative Example 1.1 500 ppm of the compound ST

are added to mixture A-1. The resulting mixture (V-1.1) is also examined for its decomposition temperature. The result is also included in Table 1 for comparison. Comparative Example 1.2 500 ppm of compound DST

are added to mixture A-1. The resulting mixture (V-1.2) is also examined for its decomposition temperature. The result is also included in Table 1 for comparison.

example 1

500 ppm of compound G-1 is added to mixture A-1. The resulting mixture (A-1.1) is also examined for its decomposition temperature. The result is in Table 1 shown. Table 1 Exp. No. Mixture no. Stable. Konz./ppm T (decomposition) / ° C .DELTA.T / degree 1.0 A-1 = V-1.0 none 0 100 none 1.1 V-1.1 ST 500 102 2 1.2 V-1.2 DST 500 104 4 1.3 A-1.1 G-1 500 > 160 > 60

Example 2:

The following mixture (A-2) is prepared and tested. Mixture A-2 composition Physical Properties connection concentration T (N, I) = 71.0 ° C Δn (20 ° C, 589 nm) = 0.0702 Δε (20 °, 1 kHz) = -3.6 γ ₁ (20 ° C) = 138 mPa · s No. abbreviation / Mass% 1 CX-V-4 20.0 2 CY-3-O4 9.6 3 CY-5-O4 9.6 4 CCY-2-O2 9.6 5 CCY-3-O2 9.6 6 CCY-5-O2 6.4 7 CCY-2-1 9.6 8th CCY-3-1 6.4 9 CC-3-4 6.4 10 CP-5-3 12.8 Σ 100.0

The host mixture A-2 is assayed as described in Example 1 and treated as the mixture A-1 with 500 ppm of compound G-1. The results are summarized in the following table, Table 2. Table 2 Exp. No. Mixture no. Stable. Konz./ppm T (decomposition) / ° C .DELTA.T / degree 2.0 A-2 = 2.0 V none 0 104 none 2.1 A-2-1 G-1 500 155 51

Example 3:

The following mixture (A-3) is prepared and tested. Mixture A-3 composition Physical Properties connection concentration T (N, I) = 79.5 ° C Δn (20 ° C, 589 nm) = 0.0722 Δε (20 °, 1 kHz) = -3.6 γ ₁ (20 ° C) = 145 mPa · s No. abbreviation / Mass% 1 CX-3-2V 20.0 2 1 CY-3-O4 9.6 3 CY-5-O4 9.6 4 CCY-2-O2 9.6 5 CCY-3-O2 9.6 6 CCY-5-O2 6.4 7 CCY-2-1 9.6 8th CCY-3-1 6.4 9 CC-3-4 6.4 10 CP-5-3 12.8 Σ 100.0

The host mixture A-3 is assayed as described in Example 1 and treated as the mixture A-1 with 500 ppm of compound G-1. The results are summarized in the following table, Table 3. Table 3 Exp. No. Mixture no. Stable. Konz./ppm T (decomposition) / ° C .DELTA.T / degree 3.0 A-3 = V 3.0 none 0 114 none 3.1 A-3-1 G-1 500 137 23

Example 4:

The following mixture (A-4) is prepared and tested. Mixture A-4 composition Physical Properties connection concentration T (N, I) = 58.0 ° C Δn (20 ° C, 589 nm) = 0.0672 Δε (20 °, 1 kHz) = -3.3 γ ₁ (20 ° C) = 120 mPa · s No. abbreviation / Mass% 1 CX-V-2 20.0 2 CY-3-O4 9.6 3 CY-5-O4 9.6 4 CCY-2-O2 9.6 5 CCY-3-O2 9.6 6 CCY-5-O2 6.4 7 CCY-2-1 9.6 8th CCY-3-1 6.4 9 CC-3-4 6.4 10 CP-5-3 12.8 Σ 100.0

The host mixture A-4 is assayed as described in Example 1 and treated as the mixture A-1 with 500 ppm of compound G-1. The results are summarized in the following table. Table 4 Exp. No. Mixture no. Stable. none Konz./ppm T (decomposition) / ° C .DELTA.T / degree 4.0 A-4 = V-4.0 0 0 100 none 4.1 A-4-1 G-1 500 130 30

Comparative Examples 5.0 and 5.1 and Example 5:

Comparative Example 5.0:

The following mixture (A-5) is prepared and tested. Mixture A-5 composition Physical Properties connection concentration T (NI) = 67.5 ° C Δn (20 ° C, 589 nm) = 0.0673 Δε (20 °, 1 kHz) = -3.1 γ ₁ (20 ° C) = 137 mPa · s No. abbreviation / Mass% 1 CX-3-2 20.0 2 CY-3-O4 9.6 3 CY-5-O4 9.6 4 CCY-2-O2 9.6 5 CCY-3-O2 9.6 6 CCY-5-O2 6.4 7 CCY-2-1 9.6 8th CCY-3-1 6.4 9 CC-3-4 6.4 10 CP-5-3 12.8 Σ 100.0

The host mixture A-5 is examined as follows (Comparative Example 5.0). In sealed test cells, please define their stability against temperature stress (for four hours at 150 ° C) and then additionally or alternatively against irradiation with UV (two hours in a Sun-test device from Heraeus, Germany). For this purpose, the VHR of the cells was measured after 5 minutes in the oven at 100 ° C after each load. The results for mixture A-5 are included in the following table for comparison.

The reproducibility of the Voltage Holding Ratio values for different series of measurements where the results were small or even very small, typically in the region of 30% or even in the range of 10% to 20%, the reproducibility of the results was sometimes clear worse than the already low accuracy in this area anyway. However, this is not critical for the present study, since comparisons are still possible within the same series of measurements.

However, for most practical applications, insufficient stability is expected at these lowest levels.

The results of the resulting mixtures are summarized in Table 5. For each test series, at least four test cells are examined for each condition and the respective results are given as mean values of the respective individual measurements.

Comparative Example 5.1:

versetzt (Vergleichsbeispiel 5.1) und wie oben beschrieben bezüglich der Stabilität der Holding Ratio untersucht. Die Ergebnisse sind in Tabelle 5 zum Vergleich aufgenommen.Subsequently, the host mixture A-5 with 500 ppm of the compound "N" (see DE 100 50 880 A1 )

offset (Comparative Example 5.1) and examined as described above with respect to the stability of the holding ratio. The results are included in Table 5 for comparison.

Example 5:

Subsequently, the host mixture A-5 is spiked with 500 ppm G-1 and examined for the stability of the holding ratio as described above. Overall, test cells with two different polyimide alignment layers were used.

The results are shown in the following table, Table 5. Table 5 Exp. mixture polyimide connection VHR _{100 ° c} /% VHR _UV /% No. No. Cast off. Cast off. Cnc./ppm 5.0a A-5 SE none 0 35 36 5.1a A 5-V SE N 500 22 17 5.2a A-5-1 SE G-1 500 61 56 5.0b A-5 AL3046 none 0 52 50 5.1b ASV AL3046 N 500 30 20 5.2b A-5-1 AL3046 G-1 500 78 72

Remarks:

• SE:

  Manufacturer Nissan Chemicals, Japan and

  AL3046:

  Manufacturer Japan Synthetic Rubber, Japan.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2004/048500 A1 [0020]
• JP 55-023169 (A) [0021]
• JP 05-117324 (A) [0021]
• WO 02/18515 A1 [0021]
• JP 09-291282 (A) [0021]
• DE 19714231 [0022]
• DE 18723275 [0022]
• DE 19831712 [0022]
• DE 19945890 [0022]
• DE 10050880 [0023]
• EP 0240379 [0138]
• DE 10050880 A1 [0180]

Cited non-patent literature

• MF Schieckel and K. Fahrenschon, "Deformation of nematic liquid crystals with vertical orientation in electrical fields", Appl. Phys. Lett. 19 (1971), 3912 [0002]
• JF Kahn (Appl Phys Lett 20 (1972), 1193) [0002]
• G. Labrunie and J. Robert (J. Appl. Phys. 44 (1973), 4869) [0002]
• J. Robert and F. Clerc (SID 80 Digest Techn. Papers (1980), 30) [0003]
• J. Duchene (Displays 7 (1986), 3) [0003]
• H. Schad (SID 82 Digest Techn. Papers (1982), 244) [0003]
• TOGASHI, S., SEKIGUCHI, K., TANABE, H., YAMAMOTO, E., SORIMACHI, K., TAJIMA, E., WATANABE, H., SHIMIZU, H., Proc. Eurodisplay 84, Sept. 1984: A 210-288 Matrix LCD Controlled by Double Stage Diode Rings, p. 141 ff, Paris [0012]
• STROMER, M., Proc. Eurodisplay 84, Sept. 1984: Design of Thin Film Transistors for Matrix Liquid Crystal Displays, p. 145 ff, Paris [0012]
• 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 [0013]
• Yoshide, H. et al., Lecture 3.1: "MVA LCD for Notebook or Mobile PCs ...", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book I, pp. 6 to 9 [0014]
• 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 [0014]
• Kim, Sang Soo, Lecture 15.4: "New State-of-the-Art LCD PV PV Sets", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp. 760-763 [0014]
• 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 [0014]
• Souk, Jun, SID Seminar 2004, Seminar M-6: "Recent Advances in LCD Technology", Seminar Lecture Notes, M-6/1 to M-6/26 [0015]
• Miller, Ian, SID Seminar 2004, Seminar M-7: "LCD Television", Seminar Lecture Notes, M-7/1 to M-7/32 [0015]
• 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 [0015]
• Kirsch, P., Reiffenrath, V. and Bremer, M., Molecular Design and Synthesis, Synlett 1999 (4), 389 et seq. [0022]
• Kirsch, P. and Tarumi, K. Angew. Chem. Int. Ed., 1997 (37), 484 et seq. [0022]
• Kirsch, P., Heckmeier, M. and Tarumi, K., Liquid Crystals, 1999 (26), 449 et seq. [0022]
• "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status Nov. 1997, Merck KGaA, Germany [0144]

Claims (15)

Liquid-crystalline medium having a nematic phase and a negative dielectric anisotropy, which comprises a) one or more compounds of the formula

in which R ¹¹ and R ¹² independently of one another are 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-,

-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 each other, wherein in all groups one or more H atoms may be replaced by halogen atoms, and one of the existing rings

Y ^{1 is} halogen, Z ¹¹ and Z ^{12 are} 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-, -CF = 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 n is 0 or 1, and b) one or more compounds containing one or more structural elements of sub-formula IIa, in a concentration of up to 1.0% by weight,

in which R ²¹ to R ^{25 are} each independently 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 substituted 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. Medium according to claim 1, characterized in that it contains one or more compounds containing one or more structural elements of the partial formula IIa of the formula II.

wherein R ²¹ to R ^{25 have} the meanings given in claim 1 in sub-formula IIa and Z ^{21 is} -O-, -CO-, -CO-O-, -O-CO- or a single bond, Sp ²¹ - [CH ₂ ] _p or a single bond, p is an integer from 1 to 16, m is 1, 2, 3 or 4, and

R ^{26 is} an unsubstituted alkyl or alkenyl radical having up to 15 C atoms, where in these radicals also one or more CH ₂ groups is 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 to each other, Sp ²² - [ CH ₂ ] _o - or a single bond, o is an integer from 1 to 16, Z ^{22 is} -CH ₂ -CH ₂ -, -CH ₂ -CF ₂ -, -CF ₂ -CH ₂ -, -CF ₂ -CF ₂ -, -CH = CH-, -CF = CH-, -CH = CF-, -CF = CF-, -C≡C-, -CH ₂ -O-, -O-CH ₂ -, -CO-O -, -O-CO-, -CF ₂ -O-, -O-CF ₂ - or a single bond,

Medium according to claim 1 or 2, characterized in that it comprises one or more compounds selected from the group of compounds of formulas I-1 to I-8

wherein the parameters have the respective meanings given in formula 1 in formula contains. Medium according to one or more of Claims 1 to 3, characterized in that it contains one or more compounds selected from the group of the compounds of the formulas II-1 to II-7

wherein the parameters have the respective meanings given in formula 2 under formula II. Medium according to one or more of claims 1 to 4, characterized in that the total concentration of the compounds of formula 1 in the total medium is 2% or more to 40% or less. Medium according to one or more of claims 1 to 5, characterized in that it contains one or more compounds of the formula III

wherein R ³¹ and R ³² each independently have one of the meanings given in claim 1 for R ¹

Z ³¹ to Z ³³ each independently have one of the meanings given in claim 1 for Z ¹¹ , p and q are each independently 0 or 1, mean. Medium according to one or more of claims 1 to 6, characterized in that it comprises one or more compounds selected from the group of the compounds of formulas IV and V

wherein R ⁴¹ , R ⁴² , R ⁵¹ and R ⁵² each independently have one of the meanings given in claim 1 for R ¹¹ , and R ^{52 may} alternatively be H or F, one of the existing rings

and the other rings, if any, each independently

L ⁴¹ and L ⁴² each independently = C (X ⁴ ) - and one of or L ⁴¹ and L ⁴² alternatively also = N-, X ⁴ F, Cl, OCF ₃ , CF ₃ , CH ₃ , CH ₂ F, CHF ₂ , one of the rings

Z ⁵¹ to Z ⁵³ each independently have one of the meanings given in claim 1 for Z ¹¹ , r and s are each independently 0 or 1, t and u are each independently 0 or 1, mean. Medium according to one or more of claims 1 to 7, characterized in that it additionally contains one or more chiral compounds. Medium according to one or more of claims 7 and 8, characterized in that it 10-60 wt .-% of one or more compounds of formula III and / or 30-80% by weight of one or more compounds selected from the group of the compounds of the formulas IV and / or V contains, wherein the total content of all compounds in the medium is 100 wt .-%. Electro-optical display or electro-optical component characterized in that it contains a liquid-crystalline medium according to one or more of claims 1 to 9. Display according to claim 10, characterized in that it is based on the VA or ECB effect. Display according to claim 10 or 11, characterized in that it comprises an active matrix addressing device. Use of a liquid-crystalline medium according to one or more of Claims 1 to 9 in an electro-optical display or in an electro-optical component. A process for the preparation of a liquid-crystalline medium, which comprises mixing one or more compounds of the formula I according to Claim 1 with one or more compounds of the formula II according to Claim 2. Process for stabilizing a liquid-crystalline medium containing one or more compounds of the formula I according to Claim 1, characterized in that one or more compounds selected from the group of the compounds of the formulas II-1 to II-7 according to Claim 4 are added to the medium ,