EP4189035A1

EP4189035A1 - Liquid-crystalline medium and liquid-crystal display comprising the same and compounds

Info

Publication number: EP4189035A1
Application number: EP21754761.1A
Authority: EP
Inventors: Sven Christian Laut; Martina Windhorst; Constanze Brocke
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2020-07-31
Filing date: 2021-07-28
Publication date: 2023-06-07
Also published as: WO2022023400A1; TW202212544A; CN116057152A

Abstract

The invention relates to a liquid-crystalline medium having a nematic phase comprising one or more compounds of formula (L), formula (L), wherein the parameters have the meaning given in the text, to the use thereof in an electro-optical display, particularly in an active-matrix display based on the IPS or FFS effect, to displays of this type which contain a liquid-crystalline medium of this type and to the use of the compounds of formula L for improvement of the contrast and/or response times of a liquid- crystalline medium which comprises one or more additional mesogenic compounds, as specified in the text.

Description

Liquid-crystalline medium and liquid-crystal display comprising the same and compounds

The present invention relates to novel liquid-crystalline media, in particular for use in liquid-crystal displays, and to these liquid-crystal displays, particularly to liquid-crystal displays which use the IPS (in-jglane switching) or, preferably, the FFS (fringe field switching) effect using dielectrically positive liquid crystals. The last one is also called XB-FFS (extra brightness FFS) effect occasionally.

For this effect dielectrically positive liquid crystals are used, which comprise one or more compounds having at the same time a high dielectric constant parallel to the molecular director and perpendicular to the molecular director, leading to a large average dielectric constant and a high dielectric ratio and, preferably, to a relatively small dielectric anisotropy at the same time. The liquid-crystalline media optionally additionally comprise dielectrically negative, dielectrically neutral compounds or both. The liquid-crystalline media are used in a homogeneous (i.e. planar) initial alignment. The liquid- crystal media according to the invention have a positive dielectric anisotropy and comprise compounds having at the same time large dielectric constants parallel and perpendicular to the molecular director.

The media are distinguished by a particularly good representation of the black state, primarily attributable to their very low scattering. This in turn is brought about especially by their high elastic constants.

High elastic constants may also lead to higher values of the rotational viscosity (gi), and consequently to higher values of the ratio gi IW22 of the rotational viscosity (gi) to the elastic constant for the twist deformation {W22), which then leads to higher response times. Since W22 is approximately proportional to the elastic constant kn for splay deformation (the value of W22 is typically about half the value of kn), this can easily and conveniently be approximated determining gi and kn.

The contrast of an LC Display can be improved, on the one hand by a higher transmittance, which can be achieved by a higher e_± in an FFS cell layout. And, on the other hand, it can be improved by a better dark state. The latter, i.e. the dark state, is strongly influenced, amongst others, by the scattering parameter. Here liquid-crystalline media having high elastic constants lower the scattering and therefore improve the contrast of an LCD. This also leads to their excellent performance in the displays according to the invention.

IPS and FFS displays using dielectrically positive liquid crystals are well known in the field and have been widely adopted for various types of displays like e.g. desk top monitors and TV sets, but also for mobile applications.

However, recently, IPS and in particular FFS displays using dielectrically negative liquid crystals are widely adopted. The latter ones are sometimes also called or UB-FFS (ultra bright FFS). Such displays are described e.g. in US 2013/0207038 A1. These displays are characterized by a markedly increased transmission compared to the previously used IPS- and FFS displays, which have used dielectrically positive liquid crystals. These displays using conventional, dielectrically negative liquid crystals, however, have the severe disadvantage of requiring a higher operation voltage than the respective displays using dielectrically positive liquid crystals. Liquid crystalline media used for UB-FFS have a dielectric anisotropy of -0.5 or less and preferably of -1.5 or less.

Liquid crystalline media used for HB-FFS (high brightness FFS) have a dielectric anisotropy of 0.5 or more and preferably of 1.5 or more. Liquid crystalline media used for HB-FFS comprising both dielectrically negative and dielectrically positive liquid crystalline compounds, respectively mesogenic compounds are described e.g. in US 2013/0207038 A1. These media feature rather large values of e_± and of s_av. already, however, their ratio of (e_± / De) is relatively small.

According to the present invention, however, the IPS or the FFS effect with dielectrically positive liquid crystalline media in a homogeneous alignment are preferred.

Industrial application of this effect in electro-optical display elements requires LC phases which have to meet a multiplicity of requirements. Particularly important here are chemical resistance to moisture, air and physical influences, such as heat, radiation in the infrared, visible and ultraviolet regions, and direct (DC) and alternating (AC) electric fields.

Furthermore, LC phases which can be used industrially are required to have a liquid-crystalline mesophase in a suitable temperature range and low viscosity.

None of the series of compounds having a liquid-crystalline mesophase that have been disclosed hitherto includes a single compound which meets all these requirements. Mixtures of two to 25, preferably three to 18, compounds are therefore generally prepared in order to obtain substances which can be used as LC phases.

Matrix liquid-crystal displays (MLC displays) are known. Non-linear elements which can be used for individual switching of the individual pixels are, for example, active elements (i.e. transistors). The term “active matrix” is then used, where in general use is made of thin-film transistors (TFTs), which are generally arranged on a glass plate as substrate.

A distinction is made between two technologies: TFTs comprising compound semiconductors, such as, for example, CdSe, or metal oxides like ZnO or TFTs based on polycrystalline and, inter alia, amorphous silicon. The latter technology currently has the greatest commercial importance worldwide.

The TFT matrix is applied to the inside of one glass plate of the display, while the other glass plate carries the transparent counter electrode on its inside. Compared with the size of the pixel electrode, the TFT is very small and has virtually no adverse effect on the image. This technology can also be extended to fully colour-capable displays, in which a mosaic of red, green and blue filters is arranged in such a way that a filter element is located opposite each switchable pixel.

The TFT displays mostly used so far usually operate with crossed polarisers in transmission and are backlit. For TV applications, ECB (or VAN) cells or FFS cells are used, whereas monitors usually use IPS cells orTN (twisted nematic) cells, and notebooks, laptops and mobile applications usually use TN, VA or FFS cells.

The term MLC displays here encompasses any matrix display having inte grated non-linear elements, i.e. , besides the active matrix, also displays with passive elements, such as varistors or diodes (MIM = metal-insulator-metal).

MLC displays of this type are particularly suitable for TV applications, moni tors and notebooks or for displays with a high information density, for example in automobile manufacture or aircraft construction. Besides prob lems regarding the angle dependence of the contrast and the response times, difficulties also arise in MLC displays due to insufficiently high specific resistance of the liquid-crystal mixtures [TOGASHI, S., SEKIGUCHI, K., TANABE, H., YAMAMOTO, E., SORIMACHI, K., TAJIMA, E., WATANABE, H., SHIMIZU, H., Proc. Eurodisplay 84, Sept. 1984: A 210-288 Matrix LCD Controlled by Double Stage Diode Rings, pp. 141 ff. , Paris; STROMER, M., Proc. Eurodisplay 84, Sept. 1984: Design of Thin Film Transistors for Matrix Addressing of Television Liquid Crystal Displays, pp. 145 ff., Paris] With decreasing resistance, the contrast of an MLC display deteriorates. Since the specific resistance of the liquid-crystal mixture generally drops over the life of an MLC display owing to interaction with the inside surfaces of the display, a high (initial) resistance is very important for displays that have to have acceptable resistance values over a long operating period.

Displays which use the ECB effect have become established as so-called VAN (vertically aligned nematic) displays, besides IPS displays (for example: Yeo, S.D., Paper 15.3: “An LC Display for the TV Application", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp.

758 and 759) and the long-known TN displays, as one of the three more recent types of liquid-crystal display that are currently the most important, in particular for television applications.

The most important designs may be mentioned here: MVA (multi-domain vertical alignment, for example: Yoshide, H. et al. , Paper 3.1: “MVA LCD for Notebook or Mobile PCs ...”, SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book I, pp. 6 to 9, and Liu, C.T. et al. , Paper 15.1: “A 46-inch TFT-LCD HDTV Technology SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp. 750 to 753),

PVA (patterned vertical alignment, for example: Kim, Sang Soo, Paper 15.4: “Super PVA Sets New State-of-the-Art for LCD-TV", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp. 760 to 763) and ASV (advanced super view, for example: Shigeta, Mitzuhiro and Fukuoka, Hirofumi, Paper 15.2: “Development of High Quality LCDTV", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp.

754 to 757). More modern versions of the VA effect, are the so called PAVA (photo-alignment VA) and PSVA (polymer-stabilized VA).

In general form, the technologies are compared, for example, in Souk, Jun, SID Seminar 2004, Seminar M-6: “Recent Advances in LCD Technology", Seminar Lecture Notes, M-6/1 to M-6/26, and Miller, Ian, SID Seminar 2004, Seminar M-7: “LCD-Television“, Seminar Lecture Notes, M-7/1 to M-7/32. Although the response times of modern ECB displays have already been significantly improved by addressing methods with overdrive, for example: Kim, Hyeon Kyeong et al., Paper 9.1 : “A 57-in. Wide UXGA TFT-LCD for HDTV Application", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book I, pp. 106 to 109, the achievement of video-compatible response times, in particular in the switching of grey shades, is still a problem which has not yet been solved to a satisfactory extent.

ECB displays, like ASV displays, use liquid-crystalline media having negative dielectric anisotropy (De), whereas TN and to date all conventional IPS displays use liquid-crystalline media having positive dielectric anisotropy. However, presently there is an increasing demand for IPS and FFS displays utilizing dielectrically negative liquid crystalline media.

In liquid-crystal displays of this type, the liquid crystals are used as dielec trics, whose optical properties change reversibly on application of an elec trical voltage.

Since in displays in general, i.e. also in displays in accordance with these mentioned effects, the operating voltage should be as low as possible, use is made of liquid-crystal media which are generally predominantly composed of liquid-crystal compounds, all of which have the same sign of the dielectric anisotropy and have the highest possible value of the dielectric anisotropy. In general, at most relatively small proportions of neutral compounds and if possible no compounds having a sign of the dielectric anisotropy which is opposite to that of the medium are employed. In the case of liquid-crystal media having negative dielectric anisotropy e.g. for ECB or UB-FFS displays, predominantly compounds having negative dielectric anisotropy are thus em ployed. The respective liquid-crystalline media employed generally consist predominantly and usually even essentially of liquid-crystal compounds having negative dielectric anisotropy.

In the media used in accordance with the present invention, significant amounts of dielectrically positive liquid-crystal compounds and generally only very small amounts of dielectrically negative compounds or even none at all are typically employed, since in general the liquid-crystal displays are intended to have the lowest possible addressing voltages. At the same time small amounts of dielectrically neutral compounds may be beneficially used in some cases.

US 2013/0207038 A1 describes liquid crystalline media for FIB-FFS displays proposing to improve the performance of the FFS displays using liquid crystals having a positive dielectric anisotropy by the additional incorporation of dielectrically negative liquid crystals. This, however, leads to the necessity of a compensation of the negative contribution of these compounds to the overall dielectric anisotropy of the resultant media. To this end, either the concentration of the dielectrically positive materials has to be increased, which, in turn, leaves less room for the use of dielectrically neutral compounds as diluters in the mixtures, or, alternatively, compounds with a stronger positive dielectric anisotropy have to be used. Both of these alternatives have the strong drawback of increasing the response time of the liquid crystals in the displays.

Liquid crystalline media having a positive dielectric anisotropy for IPS and FFS displays have already been disclosed. In the following some examples will be given. CN 104232105 A, WO 2014/192390 and WO 2015/007131 describe liquid crystalline media with a positive dielectric anisotropy, some of which have a rather high dielectric constant perpendicular to the director.

Compounds of the following formulae are described in WO 2019/034588 A1.

The phase range of the liquid-crystal mixture should be sufficiently broad for the intended application of the display.

The response times of the liquid-crystal media in the displays also should be improved, i.e. reduced. This is particularly important for displays for television or multimedia applications. In order to improve the response times, it has repeatedly been proposed in the past to optimise the rotational viscosity of the liquid-crystal media (gi), i.e. to achieve media having the lowest possible rotational viscosity. However, the results achieved here are inadequate for many applications and therefore make it appear desirable to find further optimisation approaches.

Adequate stability of the media to extreme loads, in particular to UV exposure and heating, is very particularly important. In particular in the case of applications in displays in mobile equipment, such as, for example, mobile telephones, this may be crucial.

Besides their relatively poor transmission and their relatively long response times, the MLC displays disclosed hitherto, they have further disadvantages. These are e.g. their comparatively low contrast, their relatively high viewing- angle dependence and the difficulty in the reproduction of grey scales in these displays, especially when observed from an oblique viewing angle, as well as their inadequate VHR and their inadequate lifetime. The desired improvements of the transmission of the displays and of their response times are required in order to improve their energy efficiency, respectively their capacity to render rapidly moving pictures.

There thus continues to be a great demand for MLC displays having very high specific resistance at the same time as a large working-temperature range, short response times and a relatively low threshold voltage, with the aid of which various grey shades can be produced and which have, in particular, a good and stable VHR.

The invention has the object of providing MLC displays, not only for monitor and TV applications, but also for mobile applications such as e.g. telephones and navigation systems, which are based on the ECB, IPS or FFS effect, do not have the disadvantages indicated above, or only do so to a lesser extent, and at the same time have very high specific resistance values. In particular, it must be ensured for mobile telephones and navigation systems that they also work at extremely high and extremely low temperatures.

Surprisingly, it has been found that it is possible to achieve liquid-crystal displays which have, in particular in IPS and FFS displays, a low threshold voltage with short response times, a sufficiently broad nematic phase, favourable birefringence (Dh) and, at the same time, a high transmission, high contrast, good stability to decomposition by heating and by UV exposure, and a stable, high VHR if use is made in these display elements of nematic liquid-crystal media, which comprise at least one compound, preferably two or more compounds of formula L, preferably selected from the group of the compounds of the sub-formulae L-1 to L-4, particularly pref erably the sub-formula L-1 and/or L-2, more preferably of formula L-1, and preferably additionally one or more compounds, preferably two or more compounds, selected from the group of the compounds of the formulae II and III, the former preferably of formula 11-1 and/or II-2, and/or one or more compounds, preferably two or more compounds selected from the group of formulae IV and/or V and, preferably, one or more compounds selected from the group of formulae VII to IX, all formulae as defined herein below.

In a further preferred embodiment the liquid-crystalline media comprise one or more compounds selected from the group of the compounds of formulae I and B, preferably selected from the group of the compounds of the sub formulae 1-1 and I-2 and B-1 and B-2, respectively, particularly preferably from the sub-formula 1-1 and/or I-2 and B-1 and/or B-2, most preferably of formula I-2, B-1 and B-2 and most preferably both of formula 1-1 and of formula I-2 and of formula B-1 and/or of formula B-2.

Media of this type can be used, in particular, for electro-optical displays having active-matrix addressing for IPS - or FFS displays.

The media according to the present invention preferably additionally comprise a one or more compounds selected from the group of compounds of formulae II and III, preferably one or more compounds of formula II, more preferably in addition one or more compounds of formula III and, most preferably, additionally one or more compounds selected from the group of the compounds of formulae IV and V and, again preferably, one or more compounds selected from the group of compounds of formulae VI to IX, all formulae as defined below.

The mixtures according to the invention preferably exhibit very broad nematic phase ranges with clearing points > 70°C, very favourable 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. The mixtures according to the invention are furthermore distinguished by a good ratio of clearing point and rotational vis cosity and by a relatively high positive dielectric anisotropy.

Now, it has been found surprisingly that LCDs of the FFS type using liquid crystals with positive dielectric anisotropy may be realised using specially selected liquid crystalline media. These media are characterised by a particular combination of physical properties. Most decisive amongst these are their dielectric properties and here a high average dielectric constant (sav ), a high dielectric constant perpendicular to the director of the liquid crystal molecules (e_±) and, in particular, the relatively high ratio of these latter two values: (e_± / De).

Preferably the liquid-crystalline media according to the present invention, on the one hand, have a value of the dielectric anisotropy of 1.5 or more, preferably of 2.5 or more. On the other hand, they preferably have a dielectric anisotropy of 26 or less, preferably of 15 or less and most preferably of 10 or less.

The liquid crystalline media according to the present invention in a preferred embodiment have a positive dielectric anisotropy, preferably in the range from 1.5 or more to 20.0 or less, more preferably in the range from 2.0 or more to 15.0 or less and, most preferably in the range from 2.0 or more to 12.0.

The liquid-crystalline medium of the present invention comprises a) one or more compounds of formula L, preferably in a concentration in the range from 1 % to 40 %, more preferably in the range from 2 % to 30 %, particularly preferably in the range from 3 % to 20 %, in which

R^L1 and R ^L2 , independently of one another, denote an alkyl radical having 1 to 15 C atoms, wherein one or more Chh groups, preferably one Chh group, in these radicals may each be replaced, independently of one another, by -CºC-, -CF2O-, -OCF2-, -0-, -(CO)-O-, -0-(C=0)-, cyclo propylene, 1 ,3-cyclobutylene, 1 ,3-cyclopentylene, 1 ,3-cyclo- pentenylene, preferably by cyclopropylene or 1 ,3-cyclopentylene, preferably one CFI2 group may be replaced by a 1 ,2-cyclopropyl group, by a 1 ,3-cyclopentyl group or by a 1 ,3-cyclopentenylene group, or alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms and preferably alkyl or alkenyl, wherein one -CFI2- group may be replaced by cyclo-propylene, 1 ,3-cyclobutylene, 1 ,3- cyclopentylene, 1 ,3-cyclo-pentenylene, preferably by cyclopropylene or 1 ,3-cyclopentenylene, in such a way that O atoms are not linked directly to one another, and in which one or more FI atoms may be replaced by halogen, and

Y^L1 and Y^L2, identically or differently, denote FI, F or Cl, preferably at least one of Y^L1 and Y^L2 is FI, preferably Y^L2 is FI, and most preferably Y^L1 and Y^L2 are FI, wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group, and one or more additional compounds, preferably selected from the groups of compounds according to the following conditions b) to f) b) one or more, preferably dielectrically positive, compounds selected from the group of compounds of formulae II and III, preferably of compounds having a dielectric anisotropy of greater than 3 each, preferably one or more compounds of formula II: in which

R² denotes alkyl, alkoxy, fluorinated alkyl orfluorinated alkoxy having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms and preferably alkyl or alkenyl, on each appearance, independently of one another, denote L²¹ and L²² denote H or F, preferably L²¹ denotes F,

X² denotes halogen, halogenated alkyl or alkoxy having 1 to

3 C atoms or halogenated alkenyl or alkenyloxy having 2 or 3 C atoms, preferably F, Cl, -OCF3, -O-CFI2CF3, very preferably F, m denotes 0, 1 , 2 or 3, preferably 1 or 2 and particularly pref erably 2,

R³ denotes alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms and preferably n- alkyl, cyclopropyl, cyclopentyl or alkenyl, L³¹ and L³², independently of one another, denote H or F, preferably L³¹ denotes F,

X³ denotes halogen, halogenated alkyl or alkoxy having 1 to 3 C atoms or halogenated alkenyl or alkenyloxy having 2 or 3 C atoms, F, Cl, -OCF3, -OCFIF2, -O-CH2CF , very preferably F3,

Z³ denotes -CH₂CH₂-, -CF₂CF₂-, -COO-, trans- CH=CH-, trans- CF=CF-, -CFI₂0- or a single bond, preferably -CH₂CH₂-, -COO-, trans- CH=CH- or a single bond and very preferably -COO-, trans- CH=CH- or a single bond, and n denotes 0, 1 , 2 or 3, preferably 1 , 2 or 3 and particularly preferably 1 , wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group, c) optionally, preferably obligatory, one or more dielectrically neutral compounds selected from the group of formulae IV and V: in which

R⁴¹ and R⁴², independently of one another, have the meaning indicated above for R² under formula II, preferably R⁴¹ denotes alkyl and R⁴² denotes alkyl or alkoxy or R⁴¹ denotes alkenyl and R⁴² denotes alkyl, independently of one another and, if occurs twice, also these independently of one another, denote preferably one or more of

Z⁴¹ and Z⁴², independently of one another and, if Z⁴¹ occurs twice, also these independently of one another, denote -CH₂CH₂-, -COO-, trans- CH=CH-, trans- CF=CF-, -CFI₂O-, -CF₂O-, -CºC- or a single bond, preferably one or more thereof denotes/denote a single bond, and P denotes 0, 1 or 2, preferably 0 or 1 , and

R⁵¹ and R⁵², independently of one another, have one of the meanings given for R⁴¹ and R⁴² and preferably denote alkyl having 1 to 7 C atoms, preferably n-alkyl, particularly preferably n-alkyl having 1 to 5 C atoms, alkoxy having 1 to 7 C atoms, preferably n-alkoxy, particularly preferably n-alkoxy having 2 to 5 C atoms, alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7 C atoms, preferably having 2 to 4 C atoms, preferably alkenyloxy, preferably preferably denotes

Z⁵¹ to Z⁵³ each, independently of one another, denote -CH2-CH2-

, -CH2-O-, -CH=CH-, -CºC-, -COO- or a single bond, pref erably -CH2-CH2-, -CH2-O- or a single bond and particularly preferably a single bond, i and j each, independently of one another, denote 0 or 1 ,

(i + j) preferably denotes 0, 1 or 2, more preferably 0 or 1 and, most preferably, 1 , wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group, and with the condition that the compounds of formula L are excluded from the compounds of formula III, and d) again optionally, preferably obligatory, either alternatively or additionally, one or more dielectrically negative compounds selected from the group of formulae VI to IX: wherein

R⁶¹ denotes an unsubstituted alkyl radical having 1 to 7 C atoms, preferably a straight-chain alkyl radical, more preferably an n-alkyl radical, most preferably propyl or pentyl, an unsubstituted alkenyl radical having 2 to 7 C atoms, preferably a straight-chain alkenyl radical, particularly preferably having 2 to 5 C atoms, an unsubstituted alkoxy radical having 1 to 6 C atoms or an unsubstituted alkenyloxy radical having 2 to 6 C atoms,

R⁶² denotes an unsubstituted alkyl radical having 1 to 7 C atoms, an unsubstituted alkoxy radical having 1 to 6 C atoms or an unsubstituted alkenyloxy radical having 2 to 6 C atoms, and

I denotes 0 or 1 ,

R⁷¹ denotes an unsubstituted alkyl radical having 1 to 7 C atoms, preferably a straight-chain alkyl radical, more preferably an n-alkyl radical, most preferably propyl or pentyl, or an unsubstituted alkenyl radical having 2 to 7 C atoms, preferably a straight-chain alkenyl radical, particularly preferably having 2 to 5 C atoms,

R⁷² denotes an unsubstituted alkyl radical having 1 to 7 C atoms, preferably having 2 to 5 C atoms, an unsubstituted alkoxy radical having 1 to 6 C atoms, preferably having 1, 2, 3 or 4 C atoms, or an unsubstituted alkenyloxy radical having 2 to 6 C atoms, preferably having 2, 3 or 4 C atoms, and

R⁸¹ denotes an unsubstituted alkyl radical having 1 to 7 C atoms, preferably a straight-chain alkyl radical, more preferably an n-alkyl radical, most preferably propyl or pentyl, or an unsubstituted alkenyl radical having 2 to 7 C atoms, preferably a straight-chain alkenyl radical, particularly preferably having 2 to 5 C atoms,

R⁸² denotes an unsubstituted alkyl radical having 1 to 7 C atoms, preferably having 2 to 5 C atoms, an unsubstituted alkoxy radical having 1 to 6 C atoms, preferably having 1, 2, 3 or 4 C atoms, or an unsubstituted alkenyloxy radical having 2 to 6 C atoms, preferably having 2, 3 or 4 C atoms, preferably

Z⁸ denotes -(C=0)-0-, -CH2-O-, -CF2-O- or -CH2-CH2-, preferably

-(C=0)-0- or -CH2-O-, and o denotes 0 or 1 ,

R⁹¹ and R⁹² independently of one another have the meaning given for R⁷² above,

R⁹¹ preferably denotes an alkyl radical having 2 to 5 C atoms, preferably having 3 to 5 C atoms,

R⁹² preferably denotes an alkyl or alkoxy radical having 2 to 5 C atoms, more preferably an alkoxy radical having 2 to 4 C atoms, or an alkenyloxy radical having 2 to 4 C atoms. p and q independently of each other denote 0 or 1 , and (p + q) preferably denotes 0 or 1 , in case alternatively, preferably p = q = 1 , wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group, e) optionally, preferably obligatory, one or more compounds of formula B, preferably selected from the group of compounds of formulae B-1 and B-2, preferably in a concentration in the range from 1 % to 60 %, more preferably in the range from 2 % to 40 %, particularly preferably in the range from 3 % to 35 %, in which denotes, in each occurrence independently of one another, n denotes 1 or 2, preferably 1 ,

R¹ denotes alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy, preferably having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms, preferably alkyl, alkoxy, alkenyl or alkenyloxy, more preferably alkyl, alkenyl, alkoxy or alkenyloxy, and, most preferably alkyl, and

X¹ denotes F, Cl, fluorinated alkyl, fluorinated alkenyl, fluorinated alkoxy or fluorinated alkenlyoxy, the latter four groups preferably having 1 to 4 C atoms, more preferably F, Cl, CFs or OCFs, wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group, and f) again optionally, preferably obligatory, either alternatively or additionally, one or more compounds of formula I: in which n denotes 0 or 1 ,

R¹¹ and R¹² independently of each other denote alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy, preferably having 1 to 7 C atoms, wherein one Chh group may be replaced by a 1 ,2-cyclopropyl group, by a 1 ,3-cyclopentyl group or by a 1 ,3-cyclopentenylene group, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms and preferably alkyl, alkoxy, alkenyl or alkenyloxy, most preferably alkyl, alkoxy or alkenyloxy, and R¹¹ alternatively denotes R¹ and R¹² alternatively denotes X¹, R¹ denotes alkyl, alkoxy, fluorinated alkyl orfluorinated alkoxy, preferably having 1 to 7 C atoms, wherein one CFh group may be replaced by a 1 ,2-cyclopropyl group, by a 1 ,3-cyclopentyl group or by a 1 ,3-cyclopentenylene group, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl, preferably having 2 to 7 C atoms and preferably alkyl or alkenyl, and

X¹ denotes F, Cl, fluorinated alkyl, fluorinated alkenyl, fluorinated alkoxy or fluorinated alkenyoxy, the latter four groups preferably having 1 to 4 C atoms, more preferably F, Cl, CFs or OCFs, wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group, from which the compounds of formula B are excluded.

Throughout this invention 1 ,3-cyclopentenylene is a moiety selected from the group of the formulae and preferably most preferably or

Preferably the media according to the present invention comprise one or more compounds of more compounds of formula L selected from the group of compounds of formulae L-1 to L-4, preferably of formula L-1 and/or of formula L-2, and most preferably of formula L-1 , in which

R^L1 and R^L2 have the respective meanings given above, and preferably

R^L1 denotes an alkyl radical, having 1 to 15, preferably 1 to 7, most preferably 1 to 5, C atoms, preferably, n-alkyl, wherein one or more Chh groups, preferably one Chh, group may be replaced by a 1 ,2- cyclopropyl group, by a 1 ,3-cyclopentyl group or by a 1 ,3- cyclopentenylene group, or an alkenyl, radical having 2 to 15, preferably 2 to 7, most preferably 2 to 5, C atoms, preferably vinyl or 1 -E-alkenyl, and R^L2 denotes an alkyl radical, having 1 to 15, preferably 1 to 7, most preferably 1 to 5, C atoms, preferably, n-alkyl, wherein one or more Chh groups, preferably one Chh group, may be replaced by a 1 ,2- cyclopropyl group, by a 1 ,3-cyclopentyl group or by a 1 ,3- cyclopentenylene group, and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

Examples of preferred compounds of formula L, wherein a phenyl ring is substituted by an alkyl group are those selected from the group of compounds of the following formulae wherein the parameters have the respective meanings given above, including the respective preferred meanings. The liquid-crystalline media in accordance with the present invention preferably have a nematic phase.

Throughout this invention and especially for the definition of R^L1 and R^L2 alkyl means an alkyl group, which may be straight-chain or branched. Each of these radicals is preferably straight-chain and preferably has 1, 2, 3, 4, 5, 6, 7 or 8 C atoms and is accordingly preferably methyl, ethyl, n-propyl, n-butyl, n- pentyl, n-hexyl or n-heptyl.

In case alkyl means a branched alkyl group it preferably means 2-alkyl, 2- methylalkyl or 2-(2-ethyl)-alkyl, preferably 2-butyl (=1-methylpropyl), 2- methylbutyl, 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, in particular 2-methylbutyl, 2-methylbutoxy 4-methylhexyl, 2-hexyl, 2-octyl, 2- nonyl, 2-decyl and 2-dodecyl. Most preferred of these groups are 2-hexyl and 2-octyl.

Respective branched groups, especially for R^L1 and R^L2, which lead to chiral compounds are also called chiral groups in this invention. Particularly preferred chiral groups are 2-alkyl, 2-alkoxy, 2-methylalkyl, 2-methylalkoxy, 2-fluoroalkyl, 2- fluoroalkoxy, 2-(2-ethin)-alkyl, 2-(2-ethin)-alkoxy, 1,1,1 -trifluoro-2-alkyl and 1,1,1- trifluoro-2-alkoxy.

Particularly preferred chiral groups are 2-butyl (=1-methylpropyl), 2- methylbutyl, 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, in particular 2-methylbutyl, 2-methylbutoxy, 2-methylpentoxy, 3-methylpentoxy, 2-ethylhexoxy, 1-methylhexoxy, 2-octyloxy, 2-oxa-3-methylbutyl, 3-oxa-4- methylpentyl, 4-methylhexyl, 2-hexyl, 2-octyl, 2-nonyl, 2-decyl, 2-dodecyl, 6- methoxyoctoxy, 6-methyloctoxy, 6-methyloctanoyloxy, 5- methylheptyloxycarbonyl, 2-methylbutyryloxy, 3-methylvaleroyloxy, 4- methylhexanoyloxy, 2-chlorpropionyloxy, 2-chloro-3-methylbutyryloxy, 2- chloro-4-methylvaleryloxy, 2-chloro-3-methylvaleryloxy, 2-methyl-3- oxapentyl, 2-methyl-3-oxahexyl, 1-methoxypropyl-2-oxy, 1 -ethoxypropyl-2- oxy, 1 -propoxypropyl-2-oxy, 1 -butoxypropyl-2-oxy, 2-fluorooctyloxy, 2- fluorodecyloxy, 1,1,1 -trifluoro-2-octyloxy, 1,1,1 -trifluoro-2-octyl, 2- fluoromethyloctyloxy for example. Very preferred are 2-hexyl, 2-octyl, 2- octyloxy, 1,1,1 -trifluoro-2-hexyl, 1,1,1 -trifluoro-2-octyl and 1,1,1 -trifluoro-2- octyloxy.

Throughout this invention and especially for the definition of R^D alkenyl means an alkenyl group, which may be straight-chain or branched and preferably is straight chain and preferably has 2, 3, 4, 5, 6 or 7 or 8 C atoms. Preferably it is vinyl, 1 -E-alkenyl or 3-E-alkenyl, most preferably it is vinyl, 1- E-propenyl, 1-E-butenyl, 1-E-pentenyl, 3-butenyl or 3-E-pentenyl.

The compounds of the general formula L are prepared by methods known per se, as described in the literature, for example in the standard works, such as Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart, to be precise under reaction conditions which are known and are suitable for the said reactions. Use can be made here of variants which are known per se, but are not mentioned here in greater detail.

If desired, the starting materials can also be formed in situ by not isolating them from the reaction mixture, but instead immediately converting them further into the compounds of the general formula L.

Preferred synthetic pathways towards compounds according to the invention is shown in the scheme below and is further illustrated by means of the working examples. The syntheses can be adapted to the particular desired compounds of the general formula L by choice of suitable starting materials.

The compounds of formula L-1 may be synthesized as described in WO 2019/034588 A1.

The compounds of general formula L are preferably synthesized as shown in the following scheme, Scheme 1. Scheme 1 in which R^L1, R^L2, Y^L1 and Y^L2 have the respective meanings given under formula L and its respective sub-formulae above.

The compounds of formula L-3 are preferably synthesized as shown in Scheme 2.

Scheme 2 in which R^L1, R^L2 and Y^L2 have the respective meanings given under formula L and its sub-formula L-3 above. The compounds of the general formula L can be beneficially used in liquid- crystalline media. The present invention therefore also relates to a liquid- crystalline medium comprising two or more liquid-crystalline compounds, comprising one or more compounds of the general formula L.

The invention furthermore relates to a liquid-crystal display containing a liquid-crystalline medium according to the invention, in particular an IPS or FFS display, particularly preferably a FFS or SG-FFS display.

The invention furthermore relates to a liquid-crystal display of the IPS or FFS type comprising a liquid-crystal cell consisting of two substrates, where at least one substrate is transparent to light and at least one substrate has an electrode layer, and a layer, located between the substrates, of a liquid- crystalline medium comprising a polymerised component and a low- molecular-weight component, where the polymerised component is obtainable by polymerisation of one or more polymerisable compounds in the liquid-crystalline medium between the substrates of the liquid-crystal cell, preferably with application of an electrical voltage and where the low- molecular-weight component is a liquid-crystal mixture according to the invention as described above and below.

The displays in accordance with the present invention are preferably addressed by an active matrix (active matrix LCDs, AMDs for short), pref erably by a matrix of thin-film transistors (TFTs). However, the liquid crystals according to the invention can also be used in an advantageous manner in displays having other known addressing means.

The invention furthermore relates to a process for the preparation of a liquid- crystalline medium according to the invention by mixing one or more com pounds of formula L, preferably selected from the group of compounds of formulae L-1 to L-4, most preferably selected from the group of compounds of formulae L-1 to L-3, with one or more low-molecular-weight liquid- crystalline compounds, or a liquid-crystal mixture and optionally with further liquid-crystalline compounds and/or additives. The following meanings apply above and below:

The term "FFS" is, unless indicated otherwise, used to represent FFS and SG-FFS displays.

The term "mesogenic group" is known to the person skilled in the art and is described in the literature, and denotes a group which, due to the anisotropy of its attracting and repelling interactions, essentially contributes to causing a liquid-crystalline (LC) phase in low-molecular-weight or polymeric substances. Compounds containing mesogenic groups (mesogenic com pounds) do not necessarily have to have a liquid-crystalline phase themselves. It is also possible for mesogenic compounds to exhibit liquid- crystalline phase behaviour only after mixing with other compounds and/or after polymerisation. Typical mesogenic groups are, for example, rigid rod- or disc-shaped units. An overview of the terms and definitions used in connection with mesogenic or liquid-crystalline compounds is given in Pure Appl. Chem. 73(5), 888 (2001) and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368.

The term "spacer group" or “spacer” for short, also referred to as "Sp" above and below, is known to the person skilled in the art and is described in the literature, see, for example, Pure Appl. Chem. 73(5), 888 (2001) and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368. Unless indicated otherwise, the term "spacer group" or "spacer" above and below denotes a flexible group which connects the mesogenic group and the polymerisable group(s) to one another in a polymerisable mesogenic compound.

For the purposes of this invention, the term "liquid-crystalline medium" is intended to denote a medium which comprises a liquid-crystal mixture and one or more polymerisable compounds (such as, for example, reactive mesogens). The term "liquid-crystal mixture" (or "host mixture") is intended to denote a liquid-crystalline mixture which consists exclusively of unpoly- merisable, low-molecular-weight compounds, preferably of two or more liquid-crystalline compounds and optionally further additives, such as, for example, chiral dopants or stabilisers.

Particular preference is given to liquid-crystal mixtures and liquid-crystalline media which have a nematic phase, in particular at room temperature.

In a preferred embodiment of the present invention, the liquid-crystal medium comprises one or more, preferably dielectrically positive, compounds, preferably having a dielectric anisotropy of greater than 3, selected from the group of the compounds of the formulae 11-1 and II-2: in which the parameters have the respective meanings indicated above under formula II, and L²³ and L²⁴, independently of one another, denote FI or F, preferably L²³ denotes F, and has one of the meanings given for and, in the case of formulae 11-1 and II-2, X² preferably denotes F or OCF3, particularly preferably F, and, in the case of formula II-2, and and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group and/or selected from the group of the compounds of the formulae III-1 and III-2: in which the parameters have the meanings given under formula III, and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group, and the media in accordance with the present invention may comprise, alternatively or in addition to the compounds of the formulae MI-1 and/or MI-2, one or more compounds of the formula MI-3 in which the parameters have the respective meanings indicated above, and the parameters L³¹ and L³², independently of one another and of the other parameters, denote H or F, and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

The liquid-crystal medium preferably comprises compounds selected from the group of the compounds of the formulae 11-1 and II-2 in which L²¹ and L²² and/or L²³ and L²⁴ both denote F.

In a preferred embodiment, the liquid-crystal medium comprises compounds selected from the group of the compounds of the formulae 11-1 and II-2 in which L²¹, L²², L²³ and L²⁴ all denote F.

The liquid-crystal medium preferably comprises one or more compounds of the formula 11-1. The compounds of the formula 11-1 are preferably selected from the group of the compounds of the formulae 11-1 a to 11-1 e, preferably one or more compounds of formulaelM a and/or 11-1 b and/or 11-1 d, preferably of formula 11-1 a and/or 11-1 d or 11-1 b and/or 11-1 d, most preferably of formula 11-1 d: in which the parameters have the respective meanings indicated above, and L²⁵ and L²⁶, independently of one another and of the other parameters, denote H or F, and preferably in the formulae 11-1 a and 11-1 b,

L²¹ and L²² both denote F, in the formulae 11-1 c and 11-1 d,

L²¹ and L²² both denote F and/or L²³ and L²⁴ both denote F, and in formula 11-1 e,

L²¹, L²² and L²³ denote F, and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group. The liquid-crystal medium preferably comprises one or more compounds of the formula 11-2, which are preferably selected from the group of the compounds of the formulae ll-2a to ll-2k, preferably one or more compounds each of formulae ll-2a and/or ll-2h and/or ll-2j:

in which the parameters have the respective meanings indicated above, and L²⁵ to L²⁸, independently of one another, denote H or F, preferably L²⁷ and L²⁸ both denote H, particularly preferably L²⁶ denotes H, and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

The liquid-crystal medium preferably comprises compounds selected from the group of the compounds of the formulae ll-2a to ll-2k in which L²¹ and L²² both denote F and/or L²³ and L²⁴ both denote F.

In a preferred embodiment, the liquid-crystal medium comprises compounds selected from the group of the compounds of the formulae ll-2a to ll-2k in which L²¹, L²², L²³ and L²⁴ all denote F.

Especially preferred compounds of the formula II-2 are the compounds of the following formulae, particularly preferred of formulae ll-2a-1 and/or ll-2h-1 and/or ll-2k-2: in which R² and X² have the meanings indicated above, and X² preferably denotes F, and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

The liquid-crystal medium preferably comprises one or more compounds of the formula III-1. The compounds of the formula III-1 are preferably selected from the group of the compounds of the formulae Ill-l a to II 1-1 j, preferably from formulae MI-1 c, MI-1 f, MI-1 g and MI-1 j: in which the parameters have the meanings given above and preferably in which the parameters have the respective meanings indicated above, the parameters L³³ and L³⁴, independently of one another and of the other parameters, denote H or F and the parameters L³⁵ and L³⁶, independently of one another and of the other parameters, denote H or F, and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

The liquid-crystal medium preferably comprises one or more compounds of the formula MI-1 c, which are preferably selected from the group of the compounds of the formulae MI-1 c-1 to MI-1 c-5, preferably of formulae MI-1 c-1 and/or MI-1 c-2, most preferably of formula III-1 c-1 : in which R³ has the meaning indicated above and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

The liquid-crystal medium preferably comprises one or more compounds of the formula MI-1 f, which are preferably selected from the group of the compounds of the formulae MI-1 f-1 to MI-1 f-6, preferably of formulae MI-1 f-1 and/or 111-1 f-2 and/or MI-1 f-3 and /or 111-1 f-6, more preferably of formula MI-1 f-3 and/or MI-1 f-6, more preferably of formula MI-1 f-6: in which R³ has the meaning indicated above and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

The liquid-crystal medium preferably comprises one or more compounds of the formula MI-1 g, which are preferably selected from the group of the compounds of the formulae MI-1 g-1 to MI-1 g-5, preferably of formula MI-1 g-3: in which R³ has the meaning indicated above and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

The liquid-crystal medium preferably comprises one or more compounds of the formula MI-1 h, which are preferably selected from the group of the compounds of the formulae MI-1 h-1 to MI-1 h-3, preferably of the formula MI-1 h-3: in which the parameters have the meanings given above, and X³ preferably denotes F and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

The liquid-crystal medium preferably comprises one or more compounds of the formula III-1 i, which are preferably selected from the group of the compounds of the formulae III-1 i-1 and MI-1 i-2, preferably of the formula MI-1 i- 2: in which the parameters have the meanings given above, and X³ preferably denotes F and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group. The liquid-crystal medium preferably comprises one or more compounds of the formula lll-lj, which are preferably selected from the group of the compounds of the formulae MI-1 j-1 and MI-1 j-2, preferably of the formula 111-1 j- 1 : in which the parameters have the meanings given above and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

The liquid-crystal medium preferably comprises one or more compounds of the formula III-2. The compounds of the formula III-2 are preferably selected from the group of the compounds of the formulae Ml-2a and Ml-2b, preferably of formula Ml-2b: in which the parameters have the respective meanings indicated above, and the parameters L³³ and L³⁴, independently of one another and of the other parameters, denote H or F, and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

The liquid-crystal medium preferably comprises one or more compounds of the formula lll-2a, which are preferably selected from the group of the compounds of the formulae lll-2a-1 to lll-2a-6: in which R³ has the meaning indicated above, and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

The liquid-crystal medium preferably comprises one or more compounds of the formula lll-2b, which are preferably selected from the group of the compounds of the formulae lll-2b-1 to lll-2b-4, preferably lll-2b-4: in which R³ has the meaning indicated above and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group. Alternatively or in addition to the compounds of the formulae III-1 and/or III-2, the media in accordance with the present invention may comprise one or more compounds of the formula MI-3 in which the parameters have the respective meanings indicated above under formula II. I and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

These compounds are preferably selected from the group of the formulae III- 3a and Ml-3b: in which R³ has the meaning indicated above, and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group. The liquid-crystalline media in accordance with the present invention pref erably comprise one or more dielectrically neutral compounds having a dielectric anisotropy in the range from -1.5 to 3, preferably selected from the group of the compounds of the formulae VI, VII, VIII and IX.

In the present invention, the elements all include their respective isotopes. In particular, one or more H in the compounds may be replaced by D, and this is also particularly preferred in some embodiments. A correspondingly high degree of deuteration of the corresponding compounds enables, for example, detection and recognition of the compounds. This is very helpful in some cases, in particular in the case of the compounds of formula I.

In the present invention, alkyl particularly preferably denotes straight-chain alkyl, in par ticular CH3-, C2H5-, n- C3H7-, /7-C4H9- or /7-C5H11-, and alkenyl particularly preferably denotes CH2=CH-, E-CH3-CH=CH-,

CH₂=CH-CH₂-CH₂-, E-CH₃-CH=CH-CH₂-CH₂- or E-(/?-C₃H₇)-CH=CH-.

In a preferred embodiment of the present invention, the media according to the invention in each case comprise one or more compounds of formula VI selected from the group of the compounds of the formulae VI-1 and VI-2, preferably one or more compounds each of formulae VI-1 and one or more compounds of formula VI-2, in which the parameters have the respective meanings given above under formula VI, and preferably in formula VI-1

R⁶¹ and R⁶² independently of each other denote methoxy, ethoxy, propoxy, butoxy or pentoxy, preferably ethoxy, butoxy or pentoxy, more preferably ethoxy or butoxy, and most preferably butoxy. in formula VI-2

R⁶¹ preferably denotes vinyl, 1-E-propenyl, but-4-en-1-yl, pent-1- en-1 -yl or pent-3-en-1 -yl and n-propyl or n-pentyl and R⁶² denotes an unsubstituted alkyl radical having 1 to 7 C atoms, preferably having 2 to 5 C atoms, or, preferably, an unsubstituted alkoxy radical having 1 to 6 C atoms, par ticularly preferably having 2 or 4 C atoms and, most preferably, ethoxy, and

In a preferred embodiment of the present invention, the media according to the invention in each case comprise one or more compounds of formula VII selected from the group of the compounds of the formulae VII-1 to VII-3, preferably one or more compounds each of the formulae VII-1 and one or more compounds of formula VII-2, in which the parameters have the respective meanings given above under formula VII, and preferably

R⁷¹ denotes vinyl, 1-E-propenyl, but-4-en-1-yl, pent-1-en-1-yl or pent-3-en-1-yl, n-propyl or n-pentyl and R⁷² denotes an unsubstituted alkyl radical having 1 to 7 C atoms, preferably having 2 to 5 C atoms, or, preferably, an unsubstituted alkoxy radical having 1 to 6 C atoms, par ticularly preferably having 2 or 4 C atoms and, most preferably, ethoxy, and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

In a preferred embodiment of the present invention, the media according to the invention in each case comprise one or more compounds of formula VI-1 selected from the group of the following compounds:

In a preferred embodiment of the present invention, the media according to the invention in each case comprise one or more compounds of formula VI-2 selected from the group of the following compounds:

In a preferred embodiment of the present invention, the media according to the invention in each case comprise one or more compounds of formula VII-1 selected from the group of the following compounds: In a preferred embodiment of the present invention, the media according to the invention in each case comprise one or more compounds of formula VII-2 selected from the group of the following compounds:

In addition to the compounds of formula B or the preferred sub-formulae thereof, the media in accordance with the present invention preferably comprise one or more dielectrically negative compounds selected from the group of compounds of the formulae VI and VII preferably in a total concentration in the range from 5% or more to 90% or less, preferably from 10% or more to 80% or less, particularly preferably from 20% or more to 70% or less.

In a preferred embodiment of the present invention, the media according to the invention in each case comprise one or more compounds of formula VIII selected from the group of the compounds of the formulae VIII-1 to VIII-3, preferably one or more compounds each of the formulae VIII-1 and/or one or more compounds of formula VIII-3, in which the parameters have the respective meanings given above under formula VIII, and preferably

R⁸¹ denotes vinyl, 1-E-propenyl, but-4-en-1-yl, pent-1-en-1-yl or pent-3-en-1-yl, ethyl, n-propyl or n-pentyl, alkyl, preferably ethyl, n-propyl or n-pentyl and

R⁸² denotes an unsubstituted alkyl radical having 1 to 7 C atoms, preferably having 1 to 5 C atoms or an unsubstituted alkoxy radical having 1 to 6 C atoms.

In formulae VIII-1 and VIII-2 R⁸² denotes preferably alkoxy having 2 or 4 C atoms and, most preferably, ethoxy and in formula VIII-3 it denotes preferably alky, preferably methyl, ethyl or n-propyl, most preferably methyl.

In a further preferred embodiment, the medium comprises one or more compounds of formula IV, preferably of formula IVa in which R⁴¹ denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms, preferably an n-alkyl radical, particularly preferably having 2, 3, 4 or 5 C atoms, and R⁴² denotes an unsubstituted alkyl radical having 1 to 7 C atoms, an unsubstituted alkenyl radical having 2 to 7 C atoms, or an unsubstituted alkoxy radical having 1 to 6 C atoms, both preferably having 2 to 5 C atoms, an unsubstituted alkenyl radical preferably having 2, 3 or 4 C atoms, more preferably a vinyl radical or 1-propenyl radical and in particular a vinyl radical.

In a particularly preferred embodiment, the medium comprises one or more compounds of formula IV selected from the group of the compounds of the formulae IV-1 to IV-4, preferably of formula IV-1 , in which alkyl and alkyl’, independently of one another, denote alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms, alkenyl and alkenyl’, independently of one another, denote alkenyl having 2 to 5 C atoms, preferably having 2 to 4 C atoms, particularly preferably 2 C atoms, alkenyl’ preferably denotes alkenyl having 2 to 5 C atoms, preferably having 2 to 4 C atoms, particularly preferably having 2 to 3 C atoms, and alkoxy denotes alkoxy having 1 to 5 C atoms, preferably having 2 to

4 C atoms.

In a particularly preferred embodiment, the media according to the invention comprise one or more compounds of formula IV-1 and/or one or more compounds of formula IV-2.

In a further preferred embodiment, the medium comprises one or more compounds of formula V.

In a further preferred embodiment the medium comprises one or more compounds of formula I are selected from the group of compounds of formulae 1-1 and I-2: in which

R¹¹ and R¹² independently of each other denote alkyl, alkoxy, fluorinated alkyl orfluorinated alkoxy, preferably having 1 to 7 C atoms wherein one CFh group may be replaced by a 1 ,2-cyclopropyl group, by a 1 ,3-cyclopentyl group or by a 1 ,3-cyclopentenylene group, alkenyl, alkenyloxy, alkoxyalkyl orfluorinated alkenyl having 2 to 7 C atoms and preferably alkyl, alkoxy, alkenyl or alkenyloxy, most preferably alkoxy or alkenyloxy,

R¹ denotes alkyl, alkoxy, fluorinated alkyl orfluorinated alkoxy, preferably having 1 to 7 C atoms, wherein one CFh group may be replaced by a 1 ,2-cyclopropyl group, by a 1 ,3-cyclopentyl group or by a 1 ,3-cyclopentenylene group, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms and preferably alkyl or alkenyl, and

X¹ denotes F, Cl, CN, NCS, fluorinated alkyl, fluorinated alkenyl, fluorinated alkoxy orfluorinated alkenlyoxy, the latter four groups preferably having 1 to 4 C atoms, preferably F, Cl, CF3 or OCF3, more preferably F, CF3 or OCF3 and, most preferably, CF3 or OCF3.

In a further preferred embodiment the medium comprises one or more compounds of formula B, which preferably are selected from the group of compounds of formulae B-1 and B-2: in which

R¹ denotes alkyl, alkoxy, fluorinated alkyl orfluorinated alkoxy, preferably having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms and preferably alkyl or alkenyl, and X¹ denotes F, Cl, CN, NCS, fluorinated alkyl, fluorinated alkenyl, fluorinated alkoxy or fluorinated alkenlyoxy, the latter four groups preferably having 1 to 4 C atoms, preferably F, Cl, CF3 or OCF3, more preferably F, CF3, or OCF3 and, most preferably, OCF3 or CF3.

The media according to the invention preferably comprise the following compounds in the total concentrations indicated:

1 - 30 % by weight of one or more compounds selected from the group of the compounds of formula L and

0 - 30 % by weight of one or more compounds of formula I, preferably selected from the group of the compounds of the formulae 1-1 and I-2, most preferably of formula I-2 and/or

2 - 60 % by weight of one or more compounds of formula II, preferably selected from the group of the compounds of the formulae II- 1 and II-2 and/or

1 - 60 % by weight of one or more compounds of formula III, and/or

20 - 80 % by weight of one or more compounds of formula IV, and/or

0 - 25 % by weight of one or more compounds of formula V, and/or

0 - 25 % by weight of one or more compounds of formula VI, and/or

0 - 20 % by weight of one or more compounds of formula VII, and/or

0 - 30 % by weight of one or more compounds of formula VIII, preferably selected from the group of the compounds of the formulae VIII-1 and VIII-2, and/or

0 - 60 % by weight of one or more compounds of formula IX, and/ or 0 - 30 % by weight of one or more compounds selected from the group of the compounds of formula B, where the total content of all compounds of formula L, of formulae I to IX and of formula B, which are present in the medium, preferably is 95 % or more, more preferably 97 % or more and, most preferably,

100 %.

The latter condition holds for all media according to the present invention.

In a further preferred embodiment, the media in accordance with the present invention in addition to the compounds of formula L or the preferred sub formulae thereof, and to the compounds of formulae II and/or III and/or VI and/or VII and/or VIII and/or IX and/or I and/or B, preferably comprise one or more dielectrically neutral compounds selected from the group of compounds of formulae IV and V preferably in a total concentration in the range from 5 % or more to 90 % or less, preferably from 10 % or more to 80 % or less, particularly preferably from 20 % or more to 70 % or less.

The medium according to the invention in a particularly preferred embodiment comprises one or more compounds of formula L in a total concentration in the range from 3 % or more to 50 % or less, preferably in the range from 5 % or more to 30 % or less, and one or more compounds of formula II in a total concentration in the range from 5 % or more to 50 % or less, preferably in the range from 10 % or more to 40 % or less, and/or one or more compounds of formula VII-1 in a total concentration in the range from 5 % or more to 30 % or less, and/or one or more compounds of formula VII-2 in a total concentration in the range from 3 % or more to 30 % or less and/or one or more compounds of formula I in a total concentration in the range from 3 % or more to 50 % or less, preferably in the range from 5 % or more to 30 % or less, and/or one or more compounds of formula B in a total concentration in the range from 3 % or more to 50 % or less, preferably in the range from 5 % or more to 30 % or less.

Preferably the concentration of the compounds of formula L in the media according to the invention is in the range from 1 % or more to 20 % or less, more preferably from 1.5 % or more to 20 % or less, most preferably from 2 % or more to 10 % or less.

In a preferred embodiment of the present invention the concentration of the compounds of formula II in the media is in the range from 3 % or more to 60 % or less, more preferably from 5 % or more to 55 % or less, more preferably from 10 % or more to 50 % or less and, most preferably, from 15 % or more to 45 % or less.

In a preferred embodiment of the present invention the concentration of the compounds of formula VII in the media is in the range from 2 % or more to 50 % or less, more preferably from 5 % or more to 40 % or less, more preferably from 10 % or more to 35 % or less and, most preferably, from 15 % or more to 30 % or less.

In a preferred embodiment of the present invention the concentration of the compounds of formula VII-1 in the media is in the range from 1 % or more to 40 % or less, more preferably either from 2 % or more to 35 % or less, or, alternatively, from 15 % or more to 25 % or less.

In a preferred embodiment of the present invention the concentration of the compounds of formula VII-2 in the media, if present, is in the range from 1 % or more to 40 % or less, more preferably from 5 % or more to 35 % or less and, most preferably, from 10 % or more to 30 % or less. Preferably the concentration of the compounds of formula B in the media according to the invention is in the range from 1 % or more to 60 % or less, more preferably from 3 % or more to 40 % or less, most preferably from5 % or more to 35 % or less.

In a preferred embodiment of the present invention the concentration of the compounds of formula I in the media according to the invention is in the range from 1 % or more to 60 % or less, more preferably from 2 % or more to 40 % or less, most preferably from 3 % or more to 35 % or less

The present invention also relates to 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, ECB, IPS or FFS effect, preferably on the VA, IPS or FFS effect, and in particular those which are addressed by means of an active-matrix addressing device.

Accordingly, the present invention likewise relates to the use of a liquid- crystalline medium according to the invention in an electro-optical display or in an electro-optical component, and to a process for the preparation of the liquid-crystalline media according to the invention, characterised in that one or more compounds of formula B are mixed with one or more compounds of formula I, preferably with one or more compounds of the sub-formulae 1-1 and/or I-2, preferably of formula I-2 and/or one or more compounds of formula II, preferably with one or more compounds of the sub-formulae 11-1 and/or II-2 with one or more compounds of formula VII, preferably with one or more compounds of the sub-formulae VII-1 and/or VII-2, particularly preferably one or more compounds from two or more, preferably from three or more, different formulae thereof and very particularly preferably from all four of these formulae 11-1 , II-2, VII-1 and VII-2 and one or more further compounds, preferably selected from the group of the compounds of the formulae IV and V, more preferably with one or more compounds both of formula IV and of formula V. In a further preferred embodiment, the medium comprises one or more compounds of formula IV, selected from the group of the compounds of the formulae IV-2 and IV-3, in which alkyl and alkyl’, independently of one another, denote alkyl having 1 to

7 C atoms, preferably having 2 to 5 C atoms, alkoxy denotes alkoxy having 1 to 5 C atoms, preferably hav ing 2 to 4 C atoms.

In a further preferred embodiment, the medium comprises one or more compounds of formula V selected from the group of the compounds of the formulae V-1 and V-2, preferably of formulae V-1 , in which the parameters have the meanings given above under formula V, and preferably

R⁵¹ denotes alkyl having 1 to 7 C atoms or alkenyl having 2 to 7 C atoms, and R⁵² denotes alkyl having 1 to 7 C atoms, alkenyl having 2 to 7 C atoms or alkoxy having 1 to 6 C atoms, preferably alkyl or alkenyl, particularly preferably alkyl.

In a further preferred embodiment, the medium comprises one or more compounds of formula V-1 selected from the group of the compounds of the formulae V-1 a and V-1 b, in which alkyl and alkyl’, independently of one another, denote alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms, and alkenyl denotes alkenyl having 2 to 7 C atoms, preferably having 2 to

5 C atoms.

In addition, the present invention relates to a method for the reduction of the wavelength dispersion of the birefringence of a liquid-crystalline medium which comprises one or more compounds of formula II, optionally one or more compounds selected from the group of the compounds of the formulae VII-1 and VII-2 and/or one or more compounds of formula IV and/or one or more compounds of formula V, characterised in that one or more compounds of formula B are used in the medium.

Besides compounds of the formulae L, I to IX and B, other constituents may also be present, for example in an amount of up to 45 %, but preferably up to 35 %, in particular up to 10 %, of the mixture as a whole. The media according to the invention may optionally also comprise di electrically positive compounds, whose total concentration is preferably 20 % or less, more preferably 10 % or less, based on the entire medium.

In a preferred embodiment, the liquid-crystal media according to the invention comprise in total, based on the mixture as a whole,

1 % or more to 30 % or less, preferably 1.5 % or more to 20 % or less, par ticularly preferably 2 % or more to 10 % or less, of the compound of formula L, and/or

1 % or more to 20 % or less, preferably 1 % or more to 15 % or less, par ticularly preferably 2 % or more to 12 % or less, of the compound of formula B, and/or

0 % or more to 20 % or less, preferably 0 % or more to 15 % or less, par ticularly preferably 0 % or more to 12 % or less, of the compound of formula I, and/or

3 % or more to 50 % or less, preferably 4 % or more to 45 % or less, par ticularly preferably 5 % or more to 40 % or less, of compounds of formulae II and/or III, and/or

0 % or more to 35 % or less, preferably 2 % or more to 30 % or less, par ticularly preferably 3 % or more to 25 % or less, of compounds of formulae IV and/ or V, and/or

5 % or more to 50 % or less 10 % or more to 45 % or less, preferably 15 % or more to 40 % or less of compounds of the formulae VI and/or VII and/or VIII and/or IX.

The liquid-crystal media in accordance with the present invention may comprise one or more chiral compounds.

Particularly preferred embodiments of the present invention meet one or more of the following conditions, where the acronyms (abbreviations) are explained in Tables A to C and illustrated by examples in Table D.

Preferably the media according to the present invention fulfil one or more of the following conditions. i. The liquid-crystalline medium has a birefringence of 0.060 or more, par ticularly preferably 0.070 or more. ii. The liquid-crystalline medium has a birefringence of 0.200 or less, par ticularly preferably 0.180 or less. iii. The liquid-crystalline medium has a birefringence in the range from 0.090 or more to 0.160 or less. iv. The liquid-crystalline medium comprises one or more particularly pre ferred compounds of formula L, preferably selected from the (sub-) formulae L-1 to L-4, most preferably of (sub-)formula(e) L-1 to L-3. v. The liquid-crystalline medium comprises one or more particularly pre ferred compounds of formula B, preferably selected from the (sub-) formulae B-1 and B-2, most preferably of (sub-)formula B-2. vi. The liquid-crystalline medium comprises one or more particularly pre ferred compounds of formula I, preferably selected from the (sub-) formulae 1-1 and I-2, most preferably of (sub-)formula I-2. vii. The total concentration of the compounds of formula II in the mixture as a whole is 25 % or more, preferably 30 % or more, and is preferably in the range from 25 % or more to 49 % or less, particularly preferably in the range from 29 % or more to 47 % or less, and very particularly preferably in the range from 37 % or more to 44 % or less. viii. The liquid-crystalline medium comprises one or more compounds of formula IV selected from the group of the compounds of the following formulae: CC-n-V and/or CC-n-Vm and/or CC-V-V and/or CC-V-Vn and/or CC-nV-Vn, particularly preferably CC-3-V, preferably in a concentration of up to 60 % or less, particularly preferably up to 50 % or less, and optionally additionally CC-3-V1, preferably in a concentration of up to 15 % or less, and/or CC-4-V, preferably in a concentration of up to 40 % or less, particularly preferably up to 30 % or less. ix. The media comprise the compound of formula CC-n-V, preferably CC-3-V, preferably in a concentration of 1 % or more to 60 % or less, more preferably in a concentration of 3 % or more to 35 % or less. x. The total concentration of the compounds of formula CC-3-V in the mixture as a whole preferably either is 15 % or less, preferably 10 % or less or 20 % or more, preferably 25 % or more. xi. The total concentration of the compounds of formula Y-nO-Om in the mixture as a whole is 2 % or more to 30 % or less, preferably 5 % or more to 15 % or less. xii. The total concentration of the compounds of formula CY-n-Om in the mixture as a whole is 5 % or more to 60 % or less, preferably 15% or more to 45 % or less. xiii. The total concentration of the compounds of formula CCY-n-Om and/ or CCY-n-m, preferably of CCY-n-Om, in the mixture as a whole is 5 % or more to 40 % or less, preferably 1 % or more to 25 % or less. xiv. The total concentration of the compounds of formula CLY-n-Om in the mixture as a whole is 5 % or more to 40 % or less, preferably 10 % or more to 30 % or less. xv. The liquid-crystalline medium comprises one or more compounds of formula IV, preferably of the formulae IV-1 and/or IV-2, preferably in a total concentration of 1 % or more, in particular 2 % or more, and very particularly preferably 3 % or more to 50 % or less, preferably 35 % or less. xvi. The liquid-crystalline medium comprises one or more compounds of formula V, preferably of the formulae V-1 and/or V-2, preferably in a total concentration of 1 % or more, in particular 2 % or more, and very particularly preferably 15 % or more to 35 %or less, preferably to 30 % or less. xvii. The total concentration of the compounds of formula CCP-V-n, preferably CCP-V-1 , in the mixture as a whole preferably is 5 % or more to 30 % or less, preferably 15 % or more to 25 % or less. xviii. The total concentration of the compounds of formula CCP-V2-n, preferably CCP-V2-1 , in the mixture as a whole preferably is 1 % or more to 15 % or less, preferably 2 % or more to 10 % or less.

The invention furthermore relates to an electro-optical display having active- matrix addressing based on the VA, ECB, IPS, FFS or UB-FFS effect, characterised in that it contains, as dielectric, a liquid-crystalline medium in accordance with the present invention.

The liquid-crystal mixture preferably has a nematic phase range having a width of at least 70 degrees.

The rotational viscosity gi is preferably 350 mPa-s or less, preferably 250 mPa-s or less and, in particular, 150 mPa-s or less.

The mixtures according to the invention are suitable for all IPS and FFS-TFT applications using dielectrically positive liquid crystalline media, such as, e.g. XB-FFS.

The liquid-crystalline media according to the invention preferably virtually completely consist of 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 formulae L, B, I, II, III, IV, V, VI, VII, VIII and IX.

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

In a preferred embodiment, the liquid-crystal media according to the invention predominantly comprise, preferably essentially consist of and, most preferably, virtually completely consist of compounds, which do not comprise a cyano group.

In a preferred embodiment, the liquid-crystal media according to the invention comprise compounds selected from the group of the compounds of the formulae L, B, I, II, and II, IV and V and VI to IX, preferably selected from the group of the compounds of the formulae L-1 to L-4, B-1 , B-2, 1-1 , I-2, 11-1 , II-2, III-1 , III-2, IV, V, VII-1 , VII-2, VIII and IX; they preferably consist predominantly, particularly preferably essentially and very particularly preferably virtually completely of the compounds of the said formulae.

The liquid-crystal media according to the invention preferably have a nematic phase from in each case at least -10°C or less to 70°C or more, particularly preferably from -20°C or less to 80°C or more, very particularly preferably from -30°C or less to 85°C or more and most preferably from -40°C or less to 90°C or more.

The expression "have a nematic phase" here means on the one hand that no smectic phase and no crystallisation are observed at low temperatures at the corresponding temperature and on the other hand that no clearing occurs on heating out of the nematic phase. The investigation at low temperatures is carried out in a flow viscometer at the corresponding temperature and checked by storage in test cells having a cell thickness corresponding to the electro-optical application for at least 100 hours. If the storage stability at a temperature of -20°C in a corresponding test cell is 1 ,000 h or more, the medium is regarded as stable at this temperature. At temperatures of -30°C and -40°C, the corresponding times are 500 h and 250 h respectively. 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 characterised by optical anisotropy values in the moderate to low range. The birefringence values are preferably in the range from 0.075 or more to 0.130 or less, particularly preferably in the range from 0.085 or more to 0.120 or less and very particularly preferably in the range from 0.090 or more to 0.115 or less.

In this embodiment, the liquid-crystal media according to the invention have a positive dielectric anisotropy De, which preferably is in the range from 2.0 or more to 20 or less, more preferably to 15 or less, more preferably from 2.0 or more to 10 or less, particularly preferably from 2.0 or more to 9.0 or less and very particularly preferably from 2.5 or more to 8.0 or less.

The liquid-crystal media according to the invention preferably have relatively low values for the threshold voltage (Vo) in the range from 1.0 V or more to 5.0 V or less, preferably to 2.5 V or less, preferably from 1.2 V or more to 2.2 V or less, particularly preferably from 1.3 V or more to 2.0 V or less.

In addition, the liquid-crystal media according to the invention have high values for the VHR in liquid-crystal cells.

In general, liquid-crystal media having a low addressing voltage or threshold voltage here have a lower VHR than those having a higher addressing voltage or threshold voltage, and vice versa.

These preferred values for the individual physical properties are preferably also in each case maintained by the media according to the invention in combination with one another.

In the present invention, the term "compounds", also written as "com pound^)", means both one and also a plurality of compounds, unless explicitly indicated otherwise.

In a preferred embodiment, the liquid-crystalline media according to the invention comprise one or more compounds of formula L, and one or more compounds of formula B, preferably selected from the group of formulae CB-n-F, CB-n-OT, CB-n-T, LB-n-F, LB-n-OT and LB-n-T, more preferably selected from the group of formulae CB-n-OT, CB-n-T, LB-n-OT and LB-n-T, preferably selected from the group of formulae CB-n-OT, CB-n- T, and/or one or more compounds of formula II, preferably selected from the group of formulae PUQU-n-F, CDUQU-n-F, APUQU-n-F and PGUQU-n-F, and/or one or more compounds of formula III, preferably selected from the group of formulae CCP-n-OT, CGG-n-F, and CGG-n-OD, and/or one or more compounds of formulae IV and/or V, preferably selected from the group of formulae CC-n-V, CCP-n-m, CCP-V-n, CCP-V2-n and CGP-n-n and/or one or more compounds of formula VI, preferably selected from the group of formulae Y-n-Om, Y-nO-Om and/or CY-n-Om, preferably selected from the group of the compounds of the formulae Y-3-01 , Y-40-04, CY-3-02, CY-3- 04, CY-5-02 and CY-5-04, and/or optionally, preferably obligatorily, one or more compounds of formula VII-1, preferably selected from the group of compounds of the formulae CCY-n-m and CCY-n-Om, preferably of formula CCY-n-Om, preferably selected from the group of the compounds of the formulae CCY-3-02, CCY-2-02, CCY-3- 01, CCY-3-03, CCY-4-02, CCY-3-02 and CCY-5-02, and/or optionally, preferably obligatorily, one or more compounds of formula VII-2, preferably of formula CLY-n-Om, preferably selected from the group of the compounds of the formulae CLY-2-04, CLY-3-02, CLY-3-03, and/or one or more compounds of formula VIII, preferably selected from the group of formulae CZY-n-On and CCOY-n-m and/or one or more compounds of formula IX, preferably selected from the group of formulae PYP-n-m, PYP-n-mVI and PYP-n-mVI, preferably selected from the group of formulae PYP-2-3, PYP-2-4, PYP-2-5, PYP-2-V and PYP-2-2V1 , and/or one or more compounds selected from the group of formulae PGP-n-m, PGP-n-V, PGP-n-Vm, PGP-n-mV and PGP-n-m VI, preferably selected from the group of formulae PGP-2-3, PGP-2-4, PGP-2-5, PGP-1 -V, PGP-2-V and PGP-2-2V1 , and/or optionally, preferably obligatorily, one or more compounds of formula IV, preferably selected from the group of the compounds of the formulae CC-n- V, CC-n-Vm, CC-n-mVI and CC-nV-Vm, preferably CC-3-V, CC-3-V1 , CC-4- V, CC-5-V, CC-3-2V1 and CC-V-V, particularly preferably selected from the group of the compounds CC-3-V, CC-3-V1 , CC-4-V, CC-3-2V1 and CC-V-V, very particularly preferably the compound CC-3-V, and optionally additionally the compound(s) CC-4-V and/or CC-3-V1 and/or CC-3-2V1 and/or CC-V-V, and/or optionally, preferably obligatorily, one or more compounds of formula V, preferably selected from the group of formulae CCP-V-1 and/or CCP-V2-1 .

In a specific preferred embodiment of the present invention, the media according to the invention comprise one or more compounds of formula IX,

The compounds of formula IX, are also highly suitable as stabilisers in liquid- crystal mixtures, especially in case p = q = 1 and ring A⁹ = 1 ,4-phenylene. In particular, they stabilise the VHR of the mixtures against UV exposure.

In a preferred embodiment the media according to the invention comprise one or more compounds of formula IX selected from one or more formulae of the group of the compounds of the formulae IX-1 to IX-4, very particularly preferably of the formulae IX-1 to IX-3, in which the parameters have the meanings given under formula IX.

In a further preferred embodiment, the medium comprises one or more compounds of formula IX-3, preferably of formula IX-3-a, in which alkyl and alkyl’, independently of one another, denote alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms.

In case the compounds of formula IX are used in the liquid crystalline media according to the present invention, they are preferably present in a concentration of 20 % or less, more preferably of 10 % or less and, most preferably, of 5 % or less and for the individual i.e. (homologous) compounds preferably in a concentration of 10 % or less and, more preferably, of 5 % or less. For the present invention, the following definitions apply in connection with the specification of the constituents of the compositions, unless indicated otherwise in individual cases:

- "comprise": the concentration of the constituents in question in the com position is preferably 5% or more, particularly preferably 10% or more, very particularly preferably 20% or more,

- "predominantly consist of": the concentration of the constituents in ques tion in the composition is preferably 50% or more, particularly preferably 55% or more and very particularly preferably 60% or more,

- "essentially consist of": the concentration of the constituents in question in the composition is preferably 80% or more, particularly preferably 90% or more and very particularly preferably 95% or more, and

- "virtually completely consist of: the concentration of the constituents in question in the composition is preferably 98% or more, particularly preferably 99% or more and very particularly preferably 100.0%.

This applies both to the media as compositions with their constituents, which can be groups of compounds as well as individual compounds, and also to the groups of compounds with their respective constituents, the compounds. Only in relation to the concentration of an individual compound relative to the medium as a whole does the term comprise mean: the concentration of the compound or compounds in question is preferably 1% or more, particularly preferably 2% or more, very particularly preferably 4% or more.

For the present invention, "<" means less than or equal to, preferably less than, and ">" means greater than or equal to, preferably greater than.

For the present invention denote trans- 1 ,4-cyclohexylene, denotes a mixture of both cis- and frans-1, 4-cyclohexylene and and denote 1 ,4-phenylene.

For the present invention, the expression "dielectrically positive compounds" means compounds having a De of > 1.5, the expression "dielectrically neutral compounds" means compounds having -1.5 < De < 1.5 and the expression "dielectrically negative compounds” means compounds having De < -1.5. The dielectric anisotropy of the compounds is determined here by dissolving 10% of the compounds in a liquid-crystalline host and determining the capacitance of the resultant mixture in each case in at least one test cell having a cell thickness of 20 pm with homeotropic and with homogeneous surface alignment at 1 kHz. The measurement voltage is typically 0.5 V to 1.0 V, but is always lower than the capacitive threshold of the respective liquid-crystal mixture investigated.

The host mixture used for dielectrically positive and dielectrically neutral compounds is ZLI-4792 and that used for dielectrically negative compounds is ZLI-2857, both from Merck KGaA, Germany. The values for the respective compounds to be investigated are obtained from the change in the dielectric constant of the host mixture after addition of the compound to be investigated and extrapolation to 100% of the compound employed. The compound to be investigated is dissolved in the host mixture in an amount of 10%. If the solubility of the substance is too low for this purpose, the concentration is halved in steps until the investigation can be carried out at the desired temperature. The liquid-crystal media according to the invention may, if necessary, also comprise further additives, such as, for example, stabilisers and/or pleo- chroitic, e.g. dichroitic, dyes and/or chiral dopants in the usual amounts. The amount of these additives employed is preferably in total 0 % or more to 10 % or less, based on the amount of the entire mixture, particularly preferably 0.1 % or more to 6 % or less. The concentration of the individual compounds employed is preferably 0.1 % or more to 3 % or less. The concentration of these and similar additives is generally not taken into account when specifying the concentrations and concentration ranges of the liquid-crystal compounds in the liquid-crystal media.

In a preferred embodiment, the liquid-crystal media according to the invention comprise a polymer precursor which comprises one or more reactive compounds, preferably reactive mesogens, and, if necessary, also further additives, such as, for example, polymerisation initiators and/or polymeri sation moderators, in the usual amounts. The amount of these additives employed is in total 0 % or more to 10 % or less, based on the amount of the entire mixture, preferably 0.1 % or more to 2 % or less. The concentration of these and similar additives is not taken into account when specifying the concentrations and concentration ranges of the liquid-crystal compounds in the liquid-crystal media.

The compositions consist of a plurality of compounds, preferably 3 or more to 30 or fewer, particularly preferably 6 or more to 20 or fewer and very particularly preferably 10 or more to 16 or fewer compounds, which are mixed in a conventional manner. In general, the desired amount of the compounds used in lesser amount is dissolved in the compounds making up the principal constituent of the mixture. This is advantageously carried out at elevated temperature. If the selected temperature is above the clearing point of the principal constituent, completion of the dissolution operation is particularly easy to observe. However, it is also possible to prepare the liquid- crystal mixtures in other conventional ways, for example using pre-mixes or from a so-called "multi-bottle system".

The mixtures according to the invention exhibit very broad nematic phase ranges having clearing points of 65°C or more, very favourable 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 y\ .

It goes without saying to the person skilled in the art that the media according to the invention for use in VA, IPS, FFS or PALC displays may also comprise compounds in which, for example, H, N, 0, Cl, F have been replaced by the corresponding isotopes.

The structure of the liquid-crystal displays according to the invention corre sponds to the usual geometry, as described, for example, in EP-A 0240379.

The liquid-crystal phases according to the invention can be modified by means of suitable additives in such a way that they can be employed in any type of, for example, IPS and FFS LCD display that has been disclosed to date.

Table E below indicates possible dopants which can be added to the mix tures according to the invention. If the mixtures comprise one or more dopants, it is (they are) employed in amounts of 0.01 % to 4 %, preferably 0.1 % to 1.0 %.

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

For the purposes of the present invention, all concentrations are, unless explicitly noted otherwise, indicated in per cent by weight and relate to the corresponding mixture as a whole or mixture constituents, again a whole, unless explicitly indicated otherwise. In this context the term “the mixture” describes the liquid crystalline medium.

All temperature values indicated in the present invention, such as, for example, the melting point T(C,N), the smectic (S) to nematic (N) phase transition T(S,N) and the clearing point T(N,I), are indicated in degrees Celsius (°C) and all temperature differences are correspondingly indicated in differential degrees (° or degrees), unless explicitly indicated otherwise.

For the present invention, the term "threshold voltage" relates to the capaci tive threshold (Vo), also known as the Freedericksz threshold, unless explicitly indicated otherwise.

All physical properties are and have been determined in accordance with "Merck Liquid Crystals, Physical Properties of Liquid Crystals", status Nov. 1997, Merck KGaA, Germany, and apply for a temperature of 20°C, and Dh is determined at 436 nm, 589 nm and at 633 nm, and De at 1 kHz, unless explicitly indicated otherwise in each case.

The electro-optical properties, for example the threshold voltage (Vo) (capacitive measurement), are, as is the switching behaviour, determined in test cells produced at Merck Japan. The measurement cells have soda-lime glass substrates and are constructed in an ECB or VA configuration with polyimide alignment layers (SE-1211 with diluent ^**26 (mixing ratio 1 :1 ), both from Nissan Chemicals, Japan), which have been rubbed perpendicularly to one another and effect homeotropic alignment of the liquid crystals. The surface area of the transparent, virtually square ITO electrodes is 1 cm².

Unless indicated otherwise, a chiral dopant is not added to the liquid-crystal mixtures used, but the latter are also particularly suitable for applications in which doping of this type is necessary.

The rotational viscosity is determined using the rotating permanent magnet method and the flow viscosity in a modified Ubbelohde viscometer. For liquid- crystal mixtures ZLI-2293, ZLI-4792 and MLC-6608, all products from Merck KGaA, Darmstadt, Germany, the rotational viscosity values determined at 20°C are 161 mPa-s, 133 mPa-s and 186 mPa-s respectively, and the flow viscosity values (v) are 21 mm² s ¹, 14 mm² s ¹ and 27 mm² s ¹, respectively.

The dispersion of the materials may for practical purposes be conveniently characterized in the following way, which is used throughout this application unless explicitly stated otherwise. The values of the birefringence are determined at a temperature of 20°C at several fixed wavelengths using a modified Abbe refractometer with homeotropically aligning surfaces on the sides of the prisms in contact with the material. The birefringence values are determined at the specific wavelength values of 436 nm (respective selected spectral line of a low pressure mercury lamp), 589 nm (sodium “D” line) and 633 nm (wavelength of a HE-Ne laser (used in combination with an attenuator/diffusor in order to prevent damage to the eyes of the observers.

In the following table Dh is given at 589 nm and D(Dh) is given as D(Dh) = Dh(436 nm) - Dh(633 nm).

The following symbols are used, unless explicitly indicated otherwise:

Vo threshold voltage, capacitive [V] at 20°C, n_e extraordinary refractive index measured at 20°C and 589 nm, n₀ ordinary refractive index measured at 20°C and 589 nm,

Dh optical anisotropy measured at 20°C and 589 nm, l wavelength l [nm],

Dh(l) optical anisotropy measured at 20°C and wavelength l,

D(Dh) change in optical anisotropy defined as:

Dh(20°0, 436 nm) - Dh(20°0, 633 nm),

D(Dh*) “relative change in optical anisotropy” defined as: D(Dh)/Dh(20°0, 589 nm), si dielectric susceptibility perpendicular to the director at 20°C and

1 kHz, e 11 dielectric susceptibility parallel to the director at 20°C and

1 kHz,

De dielectric anisotropy at 20°C and 1 kHz,

T(N,I) or clp. clearing point [°C], v flow viscosity measured at 20°C [mm² s ¹], gi rotational viscosity measured at 20°C [mPa-s], kn elastic constant, "splay" deformation at 20°C [pN], k22 elastic constant, "twist" deformation at 20°C [pN] (k22 ~ ½ kn), k33 elastic constant, "bend" deformation at 20°C [pN], kav. average elastic constant at 20°C [pN] defined here as kav. = (³/2 kn + k33) / 3 « (kn + k22 + k33) / 3,

LTS low-temperature stability of the phase, determined in test cells, VHR voltage holding ratio,

D /HR decrease in the voltage holding ratio, and

Srel relative stability of the VHR,

The following examples explain the present invention without limiting it. However, they show the person skilled in the art preferred mixture concepts with compounds preferably to be employed and the respective con centrations thereof and combinations thereof with one another. In addition, the examples illustrate the properties and property combinations that are accessible.

For the present invention and in the following examples, the structures of the liquid-crystal compounds are indicated by means of acronyms, with the transformation into chemical formulae taking place in accordance with Tables A to C below. All radicals C_nH_2n+i, C_mH_2m+i and C1H21+1 or C_nH_2n, C_mH_2m and CiH2iare straight-chain alkyl radicals or alkylene radicals, in each case having n, m and I C atoms respectively. Preferably n, m and I are independently of each other 1 , 2, 3, 4, 5, 6, or 7. Table A shows the codes for the ring elements of the nuclei of the compound, Table B lists the bridging units, and Table C lists the meanings of the symbols for the left- and right- hand end groups of the molecules. The acronyms are composed of the codes for the ring elements with optional linking groups, followed by a first hyphen and the codes for the left-hand end group, and a second hyphen and the codes for the right-hand end group. Table D shows illustrative structures of compounds together with their respective abbreviations.

Table A: Ring elements W -CF2-CF2-

B -CF=CF-

Z -CO-O- Zl -O-CO-

X -CF=CH- XI -CH=CF- o -CH2-O- Ol -O-CH2-

Q -CF2-O- Ql -O-CF2-

Table C: End groups

On the left individually or in combiOn the right individually or in comnation bination

On the left only in combination On the right only in combination -...n...- CnH2n -...n... CnH2n

-...M...- -CFH- -...M... -CFH-

-...D...- -CF2- -...D... -CF2-

-...V...- -CH=CH- -...V... -CH=CH-

-co-o- -...Z... -CO-O-

-...Zl...- -o-co- -...Zl... -O-CO-

-...K...- -co- -...K... -CO-

-...W...- -CF=CF- -...W... -CF=CF- in which n and m are each integers, and the three dots are placeholders for other abbreviations from this table. Besides the compounds of formula L, the mixtures according to the invention preferably comprise one or more compounds of the compounds mentioned below.

The following abbreviations are used:

(n, m, k and I are, independently of one another, each an integer, preferably 1 to 9 preferably 1 to 7, k and I possibly may be also 0 and preferably are 0 to 4, more preferably 0 or 2 and most preferably 2, n preferably is 1 , 2, 3, 4 or 5, in the combination “-nO-” it preferably is 1 , 2, 3 or 4, preferably 2 or 4, m preferably is 1 , 2, 3, 4 or 5, in the combination “-Om” it preferably is 1 , 2, 3 or 4, more preferably 2 or 4. The combination “-IVm” preferably is “2V1”.)

Table D

Exemplary, preferred compounds of formula L LGG-n-m

LBf-n-OT LBfi S B-n-T

Exemplary, preferred compounds of formula B having a high e±:

Exemplary, preferred compounds of formula I having a high e±:

B-n-IV Exemplary, preferred dielectrically positive compounds

CCP-n-OT

Exemplary, preferred dielectrically neutral compounds CC-n-IV CC-n-Wm

CCP-V-m CCZPC-n-m

CPGP-n-m

Exemplary, preferred dielectrically negative compounds

CY-nV-Om PY-nV-Om

CCY-nV-Om CPY-nV-Om

CVY-V-n

PY-n-Om CPY-n-Om

CLY-n-m Table E shows chiral dopants which are preferably employed in the mixtures according to the invention.

Table E

CM 44 R-4011 / S-4011

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

Table F shows stabilisers which can preferably be employed in the mixtures according to the invention in addition to the compounds of formula L. The parameter n here denotes an integer in the range from 1 to 12. In particular, the phenol derivatives shown can be employed as additional stabilisers since they act as antioxidants.

Table F Ċ

In a preferred embodiment of the present invention, the media according to the invention comprise one or more compounds selected from the group of the compounds from Table F, in particular one or more compounds selected from the group of the compounds of the following two formulae

Examples

The following examples explain the present invention without restricting it in any way. However, the physical properties make it clear to the person skilled in the art what properties can be achieved and in what ranges they can be modified. In particular, the combination of the various properties which can preferably be achieved is thus well defined for the person skilled in the art.

Synthesis Examples

Synthesis Example 1: Synthesis of 1-(4-Ethylphenyl)-2-fluoro-4-(4- propylcvclohexen-1-yl)benzene (short “LGP-3-2”)

A mixture of [2-fluoro-4-(4-propylcyclohexen-1-yl)phenyl]boronic acid (CAS 1130350-67-2, 9.0 g, 34 mmol) and 1-bromo-4-ethyl-benzene (CAS 1585-07- 5, 5.9 g, 32 mmol) in acetone (100 ml_) is treated with bis(dibenzylidene- acetone)palladium(O) (20 mg, 35 pmol) and tris(o-tolyl)phosphine (60 mg, 0.2 mmol) at 50°C. Then aqueous sodium hydroxide (32 ml_ of a 2 M solution, 64 mmol) is added at reflux temperature, and the reaction mixture is stirred for 4 h at reflux temperature. It is cooled to room temperature and diluted with methyl-fef-butyl-ether and hydrochloric acid. The phases are separated, and the aqueous phase is extracted with methyl-fe/f-butyl-ether twice. The combined organic phases are dried (sodium sulfate) and concentrated in vacuo. The residue is purified by flash chromatography (heptane) and subsequent recrystallisation with ethanol/heptane (4/1) and heptane to give white crystals of 1-(4-ethylphenyl)-2-fluoro-4-(4-propylcyclohexen-1- yl)benzene.

LGP-3-2: phase sequence: K 56 SmA 67 N 127 I; De = 1.6; Dh = 0.209.

Synthesis Example 2: 1 -Ethyl-2-fluoro-4-[2-fluoro-4-(4-propylcvclohexen-1 - vDphenyllbenzene (short “LGG-3-2”) A mixture of [2-fluoro-4-(4-propylcyclohexen-1-yl)phenyl]boronic acid (CAS 1130350-67-2, 6.2 g, 24 mmol) and 4-bromo-1-ethyl-2-fluoro-benzene (CAS 627463-18-7, 5.0 g, 23 mmol) in acetone (50 ml_) is treated with bis(dibenzylidene-acetone)palladium(0) (10 mg, 17 pmol) and tris(o- tolyl)phosphine (30 mg, 0.1 mmol) at 50°C. Then aqueous sodium hydroxide (23 ml_ of a 2 M solution, 45 mmol) is added at reflux temperature, and the reaction mixture is stirred for 3 h at reflux temperature. It is cooled to room temperature and diluted with toluene and hydrochloric acid. The phases are separated, and the aqueous phase is extracted with toluene. The combined organic phases are washed with brine, dried (sodium sulfate) and concentrated in vacuo. The residue is purified by flash chromatography (heptane) and subsequent recrystallisation with heptane to give 1 -ethyl-2- fluoro-4-[2-fluoro-4-(4-propylcyclohexen-1-yl)phenyl]benzene as a white solid.

LGG-3-2: phase sequence: K 39 SmA 93 N 100 I; De = 2.3; Dh = 0.192. Compound Examples

In the following table the following abbreviations for the end groups are used

The physical properties are given at a temperature of 20°C and gi is given in mPa-s.

Further Compound Examples L-2

Examples of preferably used compounds LPP-3-3

Examples of preferably used compounds Mixture Examples

In the following exemplary mixtures are disclosed.

Comparative Example 1

The following mixture (CM-1) is prepared and investigated.

This mixture, mixture CM-1 , has a an average elastic constant (k_av. = (kn + ½ kn + k₃₃) / 3) of 12.9 pN and a response time parameter (g-i/kn) of 3.6 mPa-s / pN. Example 1

The following mixture (M-1 ) is prepared and investigated.

This mixture, mixture M-1 , has a k_av. of 13.8 pN and a response time parameter (g-i/kn) of 3.5 mPa-s / pN and is characterized by a very good contrast and fast switching in an FFS display. Examples 1.1 to 1.3

Alternatively, 0.05 % of the compounds of one of the formulae wherein the two 0 atoms bonded to the N atoms indicate radicals, and are added to the mixture M-1. The resultant mixtures M-1.1, M-1.2 and M-1.3 are characterized by an improved stability against severe conditions, especially against exposure to light. Example 2

The following mixture (M-2) is prepared and investigated.

This mixture, mixture M-2 is characterized by a very good contrast and fast switching in an FFS display.

Comparative Example 2

The following mixture (CM-2) is prepared and investigated.

Example 3

The following mixture (M-3) is prepared and investigated.

This mixture, mixture M-3, is characterized by a very good contrast and fast switching in an FFS display.

Example 4

The following mixture (M-4) is prepared and investigated.

This mixture, mixture M-4, has a relatively low rotational and high elastic constants and thus is characterized by a very good contrast and fast switching in an FFS display. Example 5

The following mixture (M-5) is prepared and investigated.

This mixture, mixture M-5, has a very low rotational viscosity and shows a fast response. Example 6

The following mixture (M-6) is prepared and investigated.

This mixture, mixture M-6, has high elastic constants. Example 7

The following mixture (M-7) is prepared and investigated.

This mixture, mixture M-7, has a low rotational viscosity and shows therefore a fast switching in an FFS cell.

Example 8

The following mixture (M-8) is prepared and investigated.

This mixture, mixture M-8, has a low rotational viscosity and a high elastic constant k33.

Example 9

The following mixture (M-9) is prepared and investigated.

This mixture, mixture M-9, has a relatively low rotational viscosity.

Example 10

The following mixture (M-10) is prepared and investigated.

This mixture, mixture M-10, has high elastic constants.

Example 11

The following mixture (M-11) is prepared and investigated.

This mixture, mixture M-11 , has a low rotational viscosity and a high elastic constant k33.

Example 12

The following mixture (M-12) is prepared and investigated.

This mixture, mixture M-12, has a relatively low rotational viscosity and high elastic constants.

Example 13

The following mixture (M-13) is prepared and investigated.

This mixture, mixture M-13, has a low rotational viscosity and high elastic constants kn and k33. Example 14

The following mixture (M-14) is prepared and investigated.

This mixture, mixture M-14, has a low rotational viscosity and a high elastic constant k33.

Example 15

The following mixture (M-15) is prepared and investigated.

This mixture, mixture M-15, has a low rotational viscosity and a high elastic constant k33.

Example 16

The following mixture (M-16) is prepared and investigated.

This mixture, mixture M-16, has relatively high elastic constants.

Example 17

The following mixture (M-17) is prepared and investigated.

This mixture, mixture M-17, has a very low rotational viscosity.

Example 18

The following mixture (M-18) is prepared and investigated.

This mixture, mixture M-18, like the previous one, has a very low rotational viscosity.

Example 19

The following mixture (M-19) is prepared and investigated.

This mixture, mixture M-19, has a low rotation viscosity for the given dielectric anisotropy. Example 20

The following mixture (M-20) is prepared and investigated.

This mixture, mixture M-20, has a very low rotational viscosity.

Example 21

The following mixture (M-21) is prepared and investigated.

This mixture, mixture M-21 , like the previous one, has a very low rotational viscosity. Example 22

The following mixture (M-22) is prepared and investigated.

This mixture, mixture M-22, like the previous one, has a very low rotational viscosity. Example 23

The following mixture (M-23) is prepared and investigated.

This mixture, mixture M-23, like the previous one, has a very low rotational viscosity.

Example 24

The following mixture (M-24) is prepared and investigated.

This mixture, mixture M-24, like the previous one, has a very low rotational viscosity.

Example 25

The following mixture (M-25) is prepared and investigated.

This mixture, mixture M-25, has a high K11 and a high e_± which results in high transmission in an FFS cell. Example 26

The following mixture (M-26) is prepared and investigated.

This mixture, mixture M-26, has a relatively high elastic constant kn and a high e_± which results in high Transmission in an FFS cell. Example 27

The following mixture (M-27) is prepared and investigated.

This mixture, mixture M-27, has a relatively high elastic constant kn and a high e_± which results in high transmission in an FFS cell. Example 28

The following mixture (M-28) is prepared and investigated.

This mixture, mixture M-28, has a high clearing point and high elastic constants and a high dielectric anisotropy. Example 29

The following mixture (M-29) is prepared and investigated.

This mixture, mixture M-29, has a relatively low rotational viscosity.

Example 30

The following mixture (M-30) is prepared and investigated.

This mixture, mixture M-30, has a relatively low rotational viscosity.

Example 31

The following mixture (M-31) is prepared and investigated.

This mixture, mixture M-31 , has a relatively low rotational viscosity.

Example 32

The following mixture (M-32) is prepared and investigated.

This mixture, mixture M-32, has a relatively low rotational viscosity.

Claims

Patent Claims

1. Liquid-crystalline medium having a nematic phase characterized in that it comprises one or more compounds of formula L in which

R^L1 and R^L2 , independently of one another, denote, an alkyl radical having 1 to 15 C atoms, wherein one or more CH₂ groups in these radicals may each be replaced, independently of one another, by -CºC-, -CF₂0-, -OCF₂- -0-, -(CO)-O-, -0-(C=0)-, cyclo-propylene, 1,3-cyclobutylene, 1 ,3-cyclopentylene, 1,3- cyclo-pentenylene, preferably by cyclopropylene or 1 ,3- cyclopentylene, alkenyl, alkenyloxy, alkoxyalkyl orfluorinated alkenyl having 2 to 7 C atoms and preferably alkyl or alkenyl, wherein one -CH₂- group may be replaced by cyclo-propylene, 1,3-cyclobutylene, 1 ,3-cyclopentylene, 1 ,3-cyclo-pentenylene, preferably by cyclopropylene or 1 ,3-cyclopentenylene, in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen, and

Y^L1 and Y^L2, identically or differently, denote H, F or Cl, preferably at least one of Y^L1 and Y^L2 is H, preferably Y^L2 is H, and most preferably Y^L1 is F, wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group, and one or more additional compounds.

2. Medium according to Claim 1 , characterized in that it comprises one or more compounds selected from the group of compounds of formulae II and III. in which

R² denotes alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms, on each appearance, independently of one another, are L²¹ and L²² denote H or F,

X² denotes halogen, halogenated alkyl or alkoxy having 1 to

3 C atoms or halogenated alkenyl or alkenyloxy having 2 or 3 C atoms, m denotes 0, 1 , 2 or 3,

R³ denotes alkyl, alkoxy, fluorinated alkyl orfluorinated alkoxy having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms on each appearance, independently of one another, are

L³¹ and L³², independently of one another, denote H or F,

X³ denotes halogen, halogenated alkyl or alkoxy having 1 to

3 C atoms or halogenated alkenyl or alkenyloxy having 2 or 3 C atoms,

-O-CH2CF3, -

Z³ denotes -CH2CH2-, -CF2CF2-, -COO-, trans- CH=CH-, trans- CF=CF-, -CFI2O- or a single bond, and n denotes 0, 1 , 2 or 3, wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

3. Liquid-crystalline medium according to Claim 1 or 2, characterized in that it comprises one or more dielectrically neutral compounds selected from the group of formulae IV and V: IV V in which

R⁴¹ and R⁴², independently of one another, have the meaning indicated in claim 2 for R² under formula II, also these independently of one another, denote

Z⁴¹ and Z⁴², independently of one another and, if Z⁴¹ occurs twice, also these independently of one another, denote -CH₂CH₂-, -COO-, trans- CH=CH-, trans- CF=CF-, -CFI₂O-, -CF₂O-, -C º C- or a single bond,

P denotes 0, 1 or 2,

R⁵¹ and R⁵², independently of one another, have one of the meanings given for R⁴¹ and R⁴² if present, each, independently of one another, denote

Z⁵¹ to Z⁵³ each, independently of one another, denote

-CH₂-CH₂-, -CH₂-O-, -CH=CH-, -CºC-, -COO- or a single bond, and i and j each, independently of one another, denote 0 or 1 , wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group and with the condition that compounds of formula L are excluded from the compounds of formula V.

4. Medium according to at least one of Claims 1 to 3, characterized in that it comprises one or more compounds of formula B, in which n denotes 1 or 2,

R¹ denotes alkyl, alkoxy, fluorinated alkyl, fluorinated alkoxy, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl and

X¹ denotes F, Cl, fluorinated alkyl, fluorinated alkenyl, fluorinated alkoxy or fluorinated alkenlyoxy.

5. Medium according to at least one of Claims 1 to 4, characterized in that it additionally comprises one or more compounds of formula I: n denotes 0 or 1 ,

R¹¹ and R¹² independently of each other denote alkyl, alkoxy, fluorinated alkyl having 1 to 7 C atoms, wherein on CFh group may be replaced by a 1 ,2-cyclopropyl group, by a 1 ,3-cyclopentyl group or by a 1 ,3-cyclopentenylene group, or fluorinated alkoxy, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms and R¹¹ alternatively denotes R¹ and R¹² alternatively denotes X¹,

R¹ denotes alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy, preferably having 1 to 7 C atoms wherein on CFh group may be replaced by a 1 ,2-cyclopropyl group, by a 1 ,3-cyclopentyl group or by a 1 ,3-cyclopentenylene group, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms and preferably alkyl or alkenyl, and

X¹ denotes F, Cl, fluorinated alkyl, fluorinated alkenyl, fluorinated alkoxy or fluorinated alkenyloxy, from which the compounds of formula B are excluded, and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

6. Medium according to at least one of Claims 1 to 5, characterized in that it comprises one or more compounds selected from the group of formulae VI to IX: wherein

R⁶¹ denotes an unsubstituted alkyl radical having 1 to 7 C atoms, an unsubstituted alkenyl radical having 2 to 7 C atoms, an unsubstituted alkoxy radical having 1 to 6 C atoms or an unsubstituted alkenyloxy radical having 2 to 6 C atoms,

I denotes 0 or 1 ,

R⁷¹ denotes an unsubstituted alkyl radical having 1 to 7 C atoms, or an unsubstituted alkenyl radical having 2 to 7 C atoms,

R⁷² denotes an unsubstituted alkyl radical having 1 to 7 C atoms, an unsubstituted alkoxy radical having 1 to 6 C atoms or an unsubstituted alkenyloxy radical having 2 to 6 C atoms, denotes an unsubstituted alkyl radical having 1 to 7 C atoms, or an unsubstituted alkenyl radical having 2 to 7 C atoms, denotes an unsubstituted alkyl radical having 1 to 7 C atoms, an unsubstituted alkoxy radical having 1 to 6 C atoms or an unsubstituted alkenyloxy radical having 2 to 6 C atoms, preferably having 2, 3 or 4 C atoms, denotes

Z⁸ denotes -(C=0)-0-, -CH2-O-, -CF2-O- or -CH2-CH2-, o denotes 0 or 1 ,

R⁹¹ and R⁹² independently of one another have the meaning given for R⁷² above, p and q independently of each other denote 0 or 1 , and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

7. Medium according to at least one of Claims 1 to 6, characterized in that the total concentration of the compounds of formula L in the medium as a whole is 1 % or more to 60 % or less.

8. Medium according to at least one of Claims 1 to 7, characterized in that it additionally comprises one or more chiral compounds and/or stabilizers.

9. Electro-optical display or electro-optical component, characterized in that it comprises a liquid-crystalline medium according to at least one of Claims 1 to 8.

10. Display according to Claim 9, characterized in that it is based on the IPS mode or the FFS mode.

11. Display according to Claim 9 or 10, characterized in that it contains an active-matrix addressing device.

12. Use of a medium according to at least one of Claims 1 to 8 in an electro-optical display or in an electro-optical component.

13. Process for the preparation of a liquid-crystalline medium according to one or more of Claims 1 to 8, characterized in that one or more compounds of formula L are mixed with one or more additional mesogenic compounds and optionally one or more additives.

14. Compound selected from the group of compounds of formulae L-2 to L-4 in which the parameters have the respective meanings given in claim 1 , and wherein the respective rings, and preferably the phenylene rings, optionally may each be substituted by one or two alkyl groups, preferably by methyl and/or ethyl groups, preferably by one methyl group.

15. Process for the preparation of a compound selected from the group of compounds of formulae L-2 to L-4 according to claim 14, wherein the process preferably comprises a cross-coupling reaction.