Liquid crystal medium and liquid crystal display comprising same

Abstract

The invention relates to a liquid-crystalline medium comprising one or more compounds of formula I, # imgabs0 # wherein # imgabs1 # represents # imgabs2 # and the other parameters have the meanings given herein, to the use thereof in electro-optic displays, in particular in active matrix displays based on the IPS or FFS effect, to displays of this type containing a liquid-crystalline medium of this type, and to the use thereof in electro-optic displays, in particular in active matrix displays based on the IPS or FFS effect. And to the use of a compound of formula I for improving the transmittance and / or response time of a liquid crystalline medium comprising one or more additional mesogenic compounds.

Description

[0001] This application is a divisional application of the Chinese patent application with application number 201810832003.X and filing date of July 26, 2018. Technical Field

[0002] The present invention relates to a novel liquid crystal medium, in particular a liquid crystal medium for liquid crystal displays, and these liquid crystal displays, in particular a liquid crystal display using the IPS (in-plane switching) or preferably FFS (fringe field switching) effect of dielectrically positive liquid crystals. The latter is occasionally also referred to as the SB-FFS (superbrightness FFS) effect. For this effect, a dielectrically positive liquid crystal containing one or more compounds having a high dielectric constant parallel to the molecular director and perpendicular to the molecular director is used, which results in a large average dielectric constant and a high dielectric ratio and preferably results in a relatively small dielectric anisotropy at the same time. The liquid crystal medium optionally additionally contains a dielectrically negative, dielectrically neutral compound or both. The liquid crystal medium is used with an initial alignment along a plane (i.e., a plane). The liquid crystal medium according to the present invention has a positive dielectric anisotropy and contains a compound having a large dielectric constant parallel to and perpendicular to the molecular director at the same time.

[0003] The media are characterized by particularly high transmittance and reduced response times in the respective display, which is due to their unique combination of physical properties, especially through their dielectric properties and in particular through their high (ε ⊥ / ε av. ) ratio or their higher dielectric ratio (ε ⊥ This also leads to their excellent performance in the displays according to the invention. Background Art

[0004] IPS and FFS displays using dielectric positive liquid crystals are well known in the art and have been widely adopted for many types of displays, such as desktop monitors and televisions, but also for mobile applications.

[0005] However, IPS and in particular FFS displays using dielectrically negative liquid crystals have recently been widely adopted. The latter are sometimes referred to as UB-FFS (Ultra Bright FFS). Such displays are disclosed, for example, in US 2013 / 0207038 A1. These displays are characterized by a significantly increased transmittance compared to previously used IPS and FFS displays, which are already dielectrically positive liquid crystals. However, these displays using dielectrically negative liquid crystals have a serious disadvantage: a higher operating voltage is required compared to the respective displays using dielectrically positive liquid crystals. The liquid crystal medium for UB-FFS has a dielectric anisotropy of -0.5 or less and preferably -1.5 or less.

[0006] Liquid crystal media for HB-FFS (high brightness FFS) have a dielectric anisotropy of 0.5 or more and preferably 1.5 or more. Corresponding media comprising both dielectrically negative and dielectrically positive liquid crystal compounds, or mesogenic compounds, are disclosed, for example, in US 2013 / 0207038 A1. However, these media are characterized by already having a considerable ε ⊥ and ε av values, however, their (ε ⊥ / △ε) ratio is relatively small.

[0007] However, according to the present application, the IPS or FFS effect in which the dielectrically positive liquid-crystalline medium exhibits a planar alignment is preferred.

[0008] Industrial use of this effect in electro-optical display elements requires liquid-crystal phases that must meet a variety of requirements. Of particular importance here is the chemical resistance to moisture, air and physical influences such as heat, radiation in the infrared, visible and ultraviolet regions as well as direct current (DC) and alternating current (AC) electric fields.

[0009] Furthermore, industrially usable liquid crystal phases need to have a liquid crystal mesophase in a suitable temperature range and with low viscosity.

[0010] The series of compounds having a liquid crystal mesophase which have been disclosed so far do not include a single compound which meets all of these requirements. Therefore, mixtures of 2 to 25, preferably 3 to 18 compounds are usually prepared to obtain substances which can be used as liquid crystal phases.

[0011] Matrix liquid crystal displays (MLC displays) are known. Non-linear elements that can be used for individual switching of individual pixels are, for example, active elements (ie transistors). The term "active matrix" is subsequently used, wherein thin-film transistors (TFTs) are usually used, which are usually arranged on a glass plate as substrate.

[0012] A distinction is made between two technologies: TFTs comprising compound semiconductors, for example CdSe or metal oxides such as ZnO, or TFTs based on polycrystalline and especially amorphous silicon. The latter technology is currently of greatest commercial importance worldwide.

[0013] The TFT matrix is ​​applied to the inside of one glass plate of the display, while the other glass plate carries a transparent counter electrode on its inside. The TFTs are very small compared to the size of the pixel electrodes and have almost no adverse effect on the image. The technology can also be extended to full-color capable displays, where a mosaic of red, green and blue filters is arranged in such a way that a filter element is arranged opposite each switchable pixel.

[0014] The TFT displays most commonly used to date are usually operated with transmissive crossed polarizers and are backlit. For TV applications, ECB (or VAN) cells or FFS cells are used, while monitors usually use IPS cells or TN (twisted nematic) cells, and notebook, laptop and mobile applications usually use TN, VA or FFS cells.

[0015] The term "MLC display" comprises here any matrix display with integrated non-linear elements, ie displays which, in addition to the active matrix, also have passive elements, such as varistors or diodes (MIM=metal-insulator-metal).

[0016] MLC displays of this type are particularly suitable for TV applications, monitors and notebooks or for displays with a high information density, for example in automobile construction or aircraft construction. In addition to the problems with the angular dependence of the contrast and the response time, problems also arise in MLC displays due to the insufficiently high specific resistance of the liquid crystal mixture [TOGASHI, S., SEKI-GUCHI, K., TANABE, H., YAMAMOTO, E., SORIMACHI, K., TAJIMA, E., WATANABE, H., SHIMIZU, H., Proc. Eurodisplay 84, September 1984: A 210-288 Matrix LCD Controlled by Double Stage Diode Rings, pp. 141 ff., Paris; STROMER, M., Proc. Eurodisplay 84, September 1984: Design of Thin Film Transistors for Matrix Addressing of Television Liquid Crystal Displays, pp. 145 ff., Paris]. As the resistance decreases, the contrast of the MLC display deteriorates. Since the specific resistance of the liquid crystal mixture generally decreases over the lifetime of the MLC display due to interactions with the inner surfaces of the display, a high (initial) resistance is very important for displays that must have acceptable resistance values ​​during long operation.

[0017] In addition to IPS displays (e.g. Yeo, SD, Paper 15.3: "An LC Display for the TV Application", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp. 758 and 759) and the long-known TN displays, displays using the ECB effect have established themselves as so-called VAN (vertically aligned nematic) displays as one of the three most important newer types of liquid crystal displays today, especially for television applications.

[0018] The most important designs can 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, CT 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, SangSoo, 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 Vision, for example: Shigeta, Mitzuhiro and Fukuoka, Hirofumi, Paper 15.2: "Development of High Quality LCD TV", 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 (photoaligned VA) and PSVA (polymer-stabilized VA).

[0019] In general form, some techniques 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 time of modern ECB displays has been significantly improved by using an overdrive addressing method, 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, to achieve video-compatible response times, especially in grayscale switching, there are still unsatisfactory problems.

[0020] ECB displays, such as ASV displays, use liquid crystal media with negative dielectric anisotropy (Δε), whereas TN and all conventional IPS displays to date use liquid crystal media with positive dielectric anisotropy. However, there is currently an increasing demand for IPS and FFS displays which utilize dielectrically negative liquid crystal media.

[0021] In this type of liquid crystal display, liquid crystal is used as a dielectric material whose optical properties change reversibly when a voltage is applied.

[0022] Since the operating voltage should be as low as possible in displays, i.e. also in displays according to these mentioned effects, all liquid-crystalline media are used which usually consist predominantly of liquid-crystalline compounds which all have a dielectric anisotropy of the same sign and have the highest possible dielectric anisotropy value. Usually, relatively small proportions of neutral compounds are used at most and if possible no compounds with a dielectric anisotropy of the opposite sign to the dielectric anisotropy of the medium are used. In the case of liquid-crystalline media with negative dielectric anisotropy, for example for ECB or UB-FFS displays, therefore predominantly compounds with negative dielectric anisotropy are used. The respective liquid-crystalline medium used usually consists predominantly and often even substantially of liquid-crystalline compounds with negative dielectric anisotropy.

[0023] In the media used according to the present application, a significant amount of dielectrically positive liquid crystal compounds and usually only very small amounts of dielectric compounds or even no dielectric compounds are usually employed, since liquid crystal displays are usually intended to have the lowest possible addressing voltage. At the same time, small amounts of dielectrically neutral compounds can be used advantageously in certain cases.

[0024] US 2013 / 0207038 A1 discloses a liquid crystal medium for HB-FFS displays, proposing to improve the performance of FFS displays using liquid crystals with positive dielectric anisotropy by additionally incorporating dielectrically negative liquid crystals. However, this leads to the need to compensate the negative contribution of these compounds to the overall dielectric anisotropy of the resulting medium. To this end, the concentration of dielectrically positive materials must be increased, which in turn leaves less room for using dielectrically neutral compounds as diluents in the mixture, or alternatively compounds with stronger positive dielectric anisotropy must be used. These alternatives all have the strong disadvantage of increasing the response time of the liquid crystal in the display.

[0025] Liquid crystal media with positive dielectric anisotropy for use in IPS and FFS displays have been disclosed. Some examples are given below.

[0026] CN 104232105 A discloses a liquid crystal medium having a positive dielectric anisotropy and having a dielectric ratio (ε ⊥ / △ε).

[0027] WO 2014 / 192390 also discloses liquid crystal media with positive dielectric anisotropy, which have a relatively high ε || value, but only has a dielectric ratio of about 0.5 (ε ⊥ / △ε).

[0028] WO 2015 / 007173 discloses liquid crystal media having positive dielectric anisotropy, some of which have a dielectric ratio (ε ⊥ / △ε).

[0029] Publications DE 10 2016 003 902, EP 3 081 620 and EP 3 095 834 relate to liquid-crystalline compounds or liquid-crystalline media for use in the respective displays.

[0030] The pending, as yet unpublished applications EP 17164891.8, EP 16190393.5, EP 16194162.0, EP 16197206.2 and EP 16199580.8 of the applicant of the present application also relate to liquid crystal compounds or liquid crystal media for use in various displays.

[0031] Obviously, the range of the nematic phase of the liquid crystal mixture must be broad enough to be useful for the intended display application.

[0032] The response time of liquid-crystalline media in displays must be improved, i.e. reduced. This is particularly important for displays for television or multimedia applications. In order to improve the response time, it has been repeatedly proposed in the past to optimize the rotational viscosity (γ1) of the liquid-crystalline medium, i.e. to obtain a medium with the lowest possible rotational viscosity. However, the results obtained here are insufficient for many applications and therefore it seems desirable to find methods for further optimization.

[0033] Adequate stability of the medium to extreme loads, in particular to UV exposure and heating, is very important. This can be critical, especially in the case of displays of mobile devices (eg mobile phones).

[0034] The MLC displays disclosed so far, besides their relatively poor transmittance and their relatively long response time, also have other disadvantages. These are for example their relatively low contrast, their relatively high viewing angle dependence and the difficulty of grayscale regeneration in these displays, especially when viewed from oblique viewing angles, as well as their insufficient VHR and their insufficient lifetime. The desired improvement of the transmittance of displays and their response time is needed to improve their energy efficiency or their ability to render rapidly moving pictures.

[0035] There is therefore a continuing great demand for MLC displays having a very high specific resistance and at the same time a large operating temperature range, a short response time and a low threshold voltage, with which a large number of gray scales can be produced and which in particular have a good and stable VHR. Summary of the invention

[0036] The object of the present invention is to provide MLC displays not only for monitor and TV applications, but also for mobile applications, such as telephones and navigation systems, which are based on the ECB, IPS or FFS effect, do not have the disadvantages indicated above, or have them only to a reduced extent, and at the same time have very high specific resistance values. In particular, it must be ensured that for mobile phones and navigation systems they also operate at extremely high and extremely low temperatures.

[0037] Surprisingly, it has been found that liquid-crystal displays having low threshold voltages and short response times, sufficiently broad nematic phases, advantageously relatively low birefringence (Δn) and at the same time high transmittance, good stability to decomposition by heating and UV exposure, and a stably high VHR can be obtained if a nematic liquid-crystal mixture is used in these display elements, the nematic liquid-crystal mixture comprising at least one, preferably two or more compounds of the formula I (preferably selected from the sub-formulae I-1 and I-2, particularly preferably those of the sub-formula I-2), and preferably additionally at least one, preferably two or more compounds selected from the compounds of the formulae II and III (the former preferably the formulae II-1 and / or II-2), and / or at least one, preferably two or more compounds selected from the formulae IV and / or V, and preferably one or more compounds selected from the formulae VII to IX (all formulae as defined below in the text).

[0038] Media of this type can be used in particular in electro-optical displays with active-matrix addressing, such as IPS or FFS displays.

[0039] The medium according to the invention preferably additionally comprises one or more compounds selected from the compounds of formulae II and III, preferably one or more compounds of formula II, more preferably additionally comprises one or more compounds of formula III, and most preferably additionally comprises one or more compounds selected from the compounds of formulae IV and V, and again preferably one or more compounds selected from the compounds of formulae VI to IX (all formulae are defined below).

[0040] The mixtures according to the invention exhibit a very broad nematic phase range (clearing point ≥ 70° C.), very favorable capacitance thresholds, relatively high retention values ​​and simultaneously good low temperature stability at -20° C. and -30° C., and very low rotational viscosities. The mixtures according to the invention are further characterized by a good ratio of clearing point to rotational viscosity and a relatively high positive dielectric anisotropy.

[0041] Now, it has been surprisingly found that FFS type liquid crystals using liquid crystals with positive dielectric anisotropy can be achieved by using specially selected liquid crystal media. These media are characterized by a specific combination of physical properties. The most decisive of these is their dielectric properties and here a high average dielectric constant (ε av. ), a high dielectric constant perpendicular to the director of the liquid crystal molecules (ε ⊥ ), a high value of dielectric anisotropy (Δε), and in particular, a relatively high ratio of these last two values: (ε ⊥ / △ε).

[0042] The liquid crystal media according to the present invention preferably have a positive dielectric anisotropy, preferably in the range of 1.5 or more to 20.0 or less, more preferably in the range of 3.0 or more to 8.0 or less, and most preferably in the range of 4.0 or more to 7.0 or less.

[0043] The liquid crystal media according to the present invention preferably have a dielectric constant (ε) perpendicular to the directors of the liquid crystal molecules of 5.0 or more, more preferably 6.0 or more, more preferably 7.0 or more, more preferably 8.0 or more, more preferably 9 or more, and most preferably 10.0 or more. ⊥ ).

[0044] The liquid-crystalline media according to the invention preferably have a dielectric ratio (ε ⊥ / △ε).

[0045] In a preferred embodiment of the present invention, the liquid crystal medium preferably has a positive dielectric anisotropy, preferably 1.5 or more, and preferably comprises

[0046] a) one or more compounds of formula I, preferably in a concentration range of 1% to 60%, more preferably in a range of 5% to 40%, particularly preferably in a range of 8% to 35%,

[0047]

[0048] in

[0049] express

[0050]

[0051] express

[0052]

[0053]

[0054] n represents 0 or 1, and

[0055] R 11 and R 12 independently of one another represent alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 9 C atoms (preferably having 1 to 7 C atoms), alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 9 C atoms (preferably having 2 to 7 C atoms), and preferably alkyl, alkoxy, alkenyl or alkenyloxy, most preferably alkyl, alkoxy or alkenyloxy, and

[0056] b) one or more compounds selected from the group consisting of compounds of formula II and III, which are dielectrically positive, preferably compounds each having a dielectric anisotropy of 3 or greater:

[0057]

[0058] in

[0059] R 2 represents an alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy radical having 1 to 7 C atoms, an alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl radical having 2 to 7 C atoms, and preferably an alkyl or alkenyl radical,

[0060]

[0061] In each occurrence, they are expressed independently of each other

[0062]

[0063]

[0064] Best

[0065]

[0066] L 21 and L 22 independently represent H or F, preferably L 21 Indicates F,

[0067] X 2 denotes halogen, a halogenated alkyl or alkoxy group having 1 to 3 C atoms or a halogenated alkenyl or alkenyloxy group having 2 or 3 C atoms, preferably F, Cl, -OCF3, -O-CH2CF3, -O-CH=CH2, -O-CH=CF2 or -CF3, very preferably F, Cl, -O-CH=CF2 or -OCF3, m denotes 0, 1, 2 or 3, preferably 1 or 2 and particularly preferably 1,

[0068] R 3 represents an alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy radical having 1 to 7 C atoms, an alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl radical having 2 to 7 C atoms and is preferably an alkyl or alkenyl radical,

[0069]

[0070] In each occurrence, independently

[0071]

[0072] Best

[0073]

[0074] L 31 and L 32 , independently represent H or F, preferably L 31 Indicates F,

[0075] X 3 represents 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, -OCHF2, -O-CH2CF3, -O-CH=CF2, -O-CH=CH2 or -CF3, very preferably F, Cl, -O-CH=CF2, -OCHF2 or -OCF3,

[0076] Z 3 represents -CH2CH2-, -CF2CF2-, -COO-, trans-CH=CH-, trans-CF=CF-, -CH2O- 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

[0077] n represents 0, 1, 2 or 3, preferably 1, 2 or 3 and particularly preferably 1, and

[0078] c) optionally one or more compounds selected from the group consisting of formulae IV and V, which are preferably dielectrically neutral:

[0079]

[0080] in

[0081] R 41 and R 42 Independently of each other, the above formula II for R 2 The indicated meanings, preferably R 41 represents an alkyl group and R 42 represents an alkyl group or an alkoxy group or R 41 represents alkenyl and R 42 represents an alkyl group,

[0082]

[0083] Independently of each other and if

[0084] Appears twice

[0085] These also represent independently of each other

[0086]

[0087]

[0088] Best

[0089] One or more

[0090] express

[0091]

[0092] Z 41 and Z 42 Independently of each other and if Z 41 appears twice, these also independently represent -CH2CH2-, -COO-, trans-CH=CH-, trans-CF=CF-, -CH2O-, -CF2O-, -C≡C- or a single bond, preferably one or more of which represent a single bond, and

[0093] p represents 0, 1 or 2, preferably 0 or 1, and

[0094] R 51 and R 52 Independently of each other, they have 41 and R 42 one of the meanings given and preferably represents 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 having 2 to 7 C atoms, preferably having 2 to 4 C atoms, alkenyl or alkenyloxy, preferably alkenyloxy,

[0095]

[0096] If present, each represents independently of the other

[0097]

[0098] Best

[0099]

[0100] Best express and, if present,

[0101] Preferred representation

[0102] Z 51 To Z 53each independently represents -CH2-CH2-, -CH2-O-, -CH=CH-, -C≡C-, -COO- or a single bond, preferably -CH2-CH2-, -CH2-O- or a single bond and particularly preferably a single bond,

[0103] i and j each independently represent 0 or 1,

[0104] (i+j) preferably represents 0, 1 or 2, more preferably 0 or 1, and most preferably 1.

[0105] d) optionally, alternatively or additionally, comprises one or more compounds selected from the group consisting of formulae VI to IX, which are preferably dielectrically negative:

[0106]

[0107] in

[0108] R 61 represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably a straight-chain alkyl group, more preferably a n-alkyl group, most preferably a propyl group or a pentyl group, an unsubstituted alkenyl group having 2 to 7 C atoms, preferably a straight-chain alkenyl group, particularly preferably an unsubstituted alkoxy group having 1 to 6 C atoms or an unsubstituted alkenyloxy group having 2 to 6 C atoms,

[0109] R 62 represents an unsubstituted alkyl group having 1 to 7 C atoms, an unsubstituted alkoxy group having 1 to 6 C atoms or an unsubstituted alkenyloxy group having 2 to 6 C atoms, and

[0110] l means 0 or 1,

[0111] R 71 represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably a straight-chain alkyl group, more preferably a n-alkyl group, most preferably a propyl group or a pentyl group, or an unsubstituted alkenyl group having 2 to 7 C atoms, preferably a straight-chain alkenyl group, particularly preferably an alkenyl group having 2 to 5 C atoms,

[0112] R 72 represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably having 2 to 5 C atoms, an unsubstituted alkoxy group having 1 to 6 C atoms, preferably having 1, 2, 3 or 4 C atoms, or an unsubstituted alkenyloxy group having 2 to 6 C atoms, preferably having 2, 3 or 4 C atoms, and

[0113] express

[0114]

[0115] R 81represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably a straight-chain alkyl group, more preferably a n-alkyl group, most preferably a propyl group or a pentyl group, or an unsubstituted alkenyl group having 2 to 7 C atoms, preferably a straight-chain alkenyl group, particularly preferably an alkenyl group having 2 to 5 C atoms,

[0116] R 82 represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably having 2 to 5 C atoms, an unsubstituted alkoxy group having 1 to 6 C atoms, preferably having 1, 2, 3 or 4 C atoms, or an unsubstituted alkenyloxy group having 2 to 6 C atoms, preferably having 2, 3 or 4 C atoms,

[0117] express

[0118]

[0119] Best

[0120]

[0121] More preferred

[0122]

[0123] Z 8 represents -(C=O)-O-, -CH2-O-, -CF2-O- or -CH2-CH2-, preferably

[0124] -(C=O)-O- or -CH2-O-, and

[0125] o means 0 or 1,

[0126] R 91 and R 92 Independently of each other, the above 72 The meaning given,

[0127] R 91 preferably denotes an alkyl radical having 2 to 5 C atoms, preferably having 3 to 5 C atoms,

[0128] R 92 Preferably it represents an alkyl or alkoxy group having 2 to 5 C atoms, more preferably an alkoxy group having 2 to 4 C atoms, or an alkenyloxy group having 2 to 4 C atoms.

[0129] express

[0130] p and q independently represent 0 or 1, and

[0131] (p+q) preferably represents 0 or 1, and if

[0132] express

[0133] Alternatively, preferably p=q=1, and

[0134] e) optionally, one or more stabilizers, preferably in a concentration range of 0.010% to 1.0%, more preferably in a range of 0.025% to 0.10%, particularly preferably in a range of 0.040% to 0.080%,

[0135] The liquid-crystalline media according to the present application preferably have a nematic phase.

[0136] In a preferred embodiment of the present invention, the liquid-crystalline medium comprises one or more compounds of the formula I, preferably selected from the compounds of the formulae I-1 and I-2

[0137]

[0138] where the parameters have the meanings given above and are preferably

[0139] R 11 and R 12 Independently of one another, they represent preferably 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 alkyl, alkoxy, alkenyl or alkenyloxy, most preferably alkoxy or alkenyloxy.

[0140] In a preferred embodiment, the present invention relates to a liquid-crystalline medium comprising one or more stabilizers of the formula STA

[0141]

[0142] in

[0143] express

[0144]

[0145] Best

[0146]

[0147] Best choice

[0148]

[0149] R 1A represents H, alkyl, alkenyl or alkoxy having up to 15 C atoms, wherein one or more H atoms may be replaced by halogen,

[0150] R 2Arepresents H, alkyl or alkenyl or alkoxy with up to 7 C atoms, in which one or more H atoms may be replaced by halogen,

[0151] r is 0 or 1.

[0152] Preferably, the compound of formula STA is selected from the group consisting of formula STA-1 and STA-2

[0153]

[0154] in,

[0155] n and m are independently of each other an integer from 1 to 7, preferably 1, 2 or 3, most preferably 3.

[0156] Particularly preferred compounds of formula STA-2 are compounds of formula STA-1-1

[0157]

[0158] Furthermore, the invention relates to the use of the liquid-crystal mixtures and liquid-crystal media according to the invention in IPS and FFS displays, in particular in SB-FFS displays containing liquid-crystal media, for improving the response time and / or the transmittance.

[0159] The present invention furthermore relates to a liquid-crystal display, in particular an IPS or FFS display, particularly preferably an FFS or SB-FFS display, which contains the liquid-crystal medium according to the invention.

[0160] Furthermore, the present invention relates to a liquid crystal display of the IPS or FFS type comprising a liquid crystal cell, the liquid crystal cell consisting of two substrates, at least one of which is transparent to light and at least one of which has an electrode layer, and a layer of a liquid crystal medium located between the substrates, the liquid crystal medium comprising a polymerized component and a low molecular weight component, wherein the polymerized component is obtainable by polymerization of one or more polymerizable compounds in the liquid crystal medium between the substrates of the liquid crystal cell, preferably polymerization under application of a voltage and wherein the low molecular weight component is a liquid crystal mixture according to the invention as described above and below.

[0161] The display according to the invention is preferably addressed by an active matrix (active matrix LCD, AMD for short), preferably 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 with other known addressing devices.

[0162] Furthermore, the present invention relates to a process for preparing the liquid-crystalline media according to the invention, by mixing one or more compounds of formula I, preferably selected from the group consisting of compounds of formulae I-1 and I-2, with one or more low molecular weight liquid-crystalline compounds or liquid-crystalline mixtures and optionally with further liquid-crystalline compounds and / or additives, preferably stabilizers, preferably selected from the group consisting of compounds of table F and most preferably compounds of formula STA.

[0163] The following meanings apply in this context:

[0164] Unless otherwise stated, the term "FFS" is used to refer to both FFS and SB-FFS displays.

[0165] The term "mesogenic group" is known to those skilled in the art and is described in the literature and refers to a group that substantially contributes to the induction of a liquid crystal (LC) phase in a low molecular weight or polymeric substance due to its anisotropy of attraction and repulsion interactions. A compound containing a mesogenic group (mesogenic compound) does not necessarily have a liquid crystal phase itself. A mesogenic compound may also exhibit liquid crystal phase behavior only after mixing with other compounds and / or polymerization. Typical mesogenic groups are, for example, rigid rod-shaped or disc-shaped units. An overview of the terms and definitions used in connection with mesogenic or liquid crystal compounds is given in Pure Appl. Chem. 73 (5), 888 (2001) and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368.

[0166] The term "spacer" or "spacer" for short (also referred to above and below as "Sp") is known to the person skilled in the art and is described in the literature, see for example Pure Appl. Chem. 73 (5), 888 (2001) and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368. Unless otherwise indicated, the term "spacer" or "spacer" above and below denotes a flexible group which connects the mesogenic group and the polymerizable group to each other in a polymerizable mesogenic compound.

[0167] For the purposes of the present invention, the term "liquid-crystal medium" is intended to mean a medium comprising a liquid-crystal mixture and one or more polymerizable compounds, such as reactive mesogens. The term "liquid-crystal mixture" (or "host mixture") is intended to mean a liquid-crystal mixture consisting only of non-polymerizable low molecular weight compounds, preferably two or more liquid-crystal compounds, and optionally other additives, such as chiral dopants or stabilizers.

[0168] Particular preference is given to liquid-crystal mixtures and liquid-crystal media which have a nematic phase, in particular at room temperature.

[0169] In a preferred embodiment of the present invention, the liquid crystal medium comprises one or more dielectrically positive compounds having a dielectric anisotropy of 3 or more, which are selected from the compounds of the formulae II-1 and II-2:

[0170]

[0171] wherein the parameters have the respective meanings indicated above under formula II, and L 23 and L 24 independently represent H or F, preferably L 23 represents F, and

[0172] With One of the meanings given,

[0173] In the case of formula II-1 and II-2, X 2 Preferably represents F or OCF3, particularly preferably F, and in the case of formula II-2,

[0174]

[0175] Independently of each other, preferred representation

[0176]

[0177] and / or a compound selected from formula III-1 and III-2:

[0178]

[0179] wherein the parameters have the meanings given under formula III,

[0180] Alternatively or in addition to the compounds of formula III-1 and / or III-2, the media according to the invention may also contain one or more compounds of formula III-3

[0181]

[0182] where the parameters have the meanings indicated above, and the parameter L 31 and L 32 Expresses H or F independently of each other and of other parameters.

[0183] The liquid-crystalline medium preferably comprises a compound selected from the group consisting of compounds of the formulae II-1 and II-2, in which L 21 and L 22 and / or L 23 and L 24 Both represent F.

[0184] In a preferred embodiment, the liquid crystal medium comprises a compound selected from the group consisting of compounds of the formulae II-1 and II-2, wherein L 21 , L 22 , L 23 and L 24 Both represent F.

[0185] The liquid crystal medium preferably comprises one or more compounds of formula II-1. The compound of formula II-1 is preferably selected from the compounds of formulae II-1a to II-1e, preferably one or more compounds of formulae II-1a and / or II-1b and / or II-1d, preferably selected from formulae II-1a and / or II-1d or II-1b and / or II-1d, most preferably selected from formula II-1d:

[0186]

[0187]

[0188] The parameters have the meanings indicated above, and L 25 and L 26 represents H or F independently of each other and of the other parameters, and preferably

[0189] In formula II-1a and II-1b,

[0190] L 21 and L 22 All represent F,

[0191] In formula II-1c and II-1d,

[0192] L 21 and L 22 All represent F and / or L 23 and L 24 Both represent F, and

[0193] In formula II-1e,

[0194] L 21 , L 22 and L 23 Indicates F.

[0195] The liquid-crystalline medium preferably comprises one or more compounds of the formula II-2, which are preferably selected from the compounds of the formulae II-2a to II-2k, preferably one or more compounds each of the formulae II-2a and / or II-2h and / or II-2j;

[0196]

[0197]

[0198]

[0199] where the parameters have the respective meanings indicated above, and L 25 To L 28 independently represent H or F, preferably L 27 and L 28 All represent H, and L is particularly preferred 26 Indicates H.

[0200] The liquid-crystalline medium preferably comprises a compound selected from the group consisting of compounds of the formulae II-1a to II-1e, in which L 21 and L 22 All represent F and / or L 23 and L 24 Both represent F.

[0201] In a preferred embodiment, the liquid-crystalline medium comprises a compound selected from the group consisting of compounds of the formulae II-2a to II-2k, in which L 21 , L 22 , L 23 and L 24 Both represent F.

[0202] Particularly preferred compounds of formula II-2 are compounds of the following formulae, particularly preferably formulae II-2a-1 and / or II-2h-1 and / or II-2k-2:

[0203]

[0204]

[0205]

[0206] Where R 2 and X 2 has the meaning indicated above, and X 2 Preferably it represents F.

[0207] The liquid crystal medium preferably comprises one or more compounds of the formula III-1. The compound of the formula III-1 is preferably selected from the compounds of the formulae III-1a to III-1j, preferably from the formulae III-1c, III-1f, III-1g and III-1j:

[0208]

[0209]

[0210]

[0211] wherein the parameters have the meanings given above and preferably wherein the parameters have the respective meanings indicated above, the parameter L35 and L 36 Independently of each other and of the other parameters, H or F, and parameter L 35 and L 36 H or F is expressed independently of each other and of other parameters.

[0212] The liquid crystal medium preferably comprises one or more compounds of the formula III-1c, which are preferably selected from the compounds of the formulae III-1c-1 to III-1c-5, preferably the formula III-1c-1 and / or III-1c-2, most preferably the formula III-1c-1:

[0213]

[0214] Where R 3 has the meaning indicated above.

[0215] The liquid crystal medium preferably comprises one or more compounds of the formula III-1f, which are preferably selected from the compounds of the formulae III-1f-1 to III-1f-6, preferably formula III-1f-1 and / or III-1f-2 and / or III-1f-3 and / or III-1f-6, more preferably formula III-1f-3 and / or III-1f-6, more preferably formula III-1f-6:

[0216]

[0217] Where R 3 has the meaning indicated above.

[0218] The liquid-crystalline medium preferably comprises one or more compounds of the formula III-1g, which are preferably selected from the compounds of the formulae III-1g-1 to III-1g-5, preferably the formula III-1g-3:

[0219]

[0220] Where R 3 has the meaning indicated above.

[0221] The liquid-crystalline medium preferably comprises one or more compounds of the formula III-1h, which are preferably selected from the compounds of the formulae III-1h-1 to III-1h-3, preferably the formula III-1h-3:

[0222]

[0223]

[0224] where the parameters have the meanings given above, and X 3 Preferably it represents F.

[0225] The liquid-crystalline medium preferably comprises one or more compounds of the formula III-1i, which are preferably selected from the compounds of the formulae III-1i-1 and III-1i-2, preferably the formula III-1i-2:

[0226]

[0227] where the parameters have the meanings given above, and X 3 Preferably it represents F.

[0228] The liquid-crystalline medium preferably comprises one or more compounds of the formula III-1j, which are preferably selected from the compounds of the formulae III-1j-1 and III-1j-2, preferably the formula III-1j-1:

[0229]

[0230] where the parameters have the meanings given above.

[0231] The liquid crystal medium preferably comprises one or more compounds of formula III-2. The compound of formula III-2 is preferably selected from the compounds of formula III-2a and III-2b, preferably formula III-2b:

[0232]

[0233] where the parameters have the meanings indicated above, and the parameter L 33 and L 34 H or F is expressed independently of each other and of other parameters.

[0234] The liquid-crystalline medium preferably comprises one or more compounds of the formula III-2a, which are preferably selected from the compounds of the formulae III-2a-1 to III-2a-6:

[0235]

[0236]

[0237] Where R 3 has the meaning indicated above.

[0238] The liquid-crystalline medium preferably comprises one or more compounds of the formula III-2b, which are preferably selected from the compounds of the formulae III-2b-1 to III-2b-4, preferably III-2b-4:

[0239]

[0240] Where R 3 has the meaning indicated above.

[0241] Alternatively or in addition to the compounds of formula III-1 and / or III-2, the medium according to the invention may also contain one or more compounds of formula III-3

[0242]

[0243] wherein the parameters have the respective meanings indicated above under formula III.

[0244] These compounds are preferably selected from the formulae III-3a and III-3b:

[0245]

[0246] Where R 3 has the meaning indicated above.

[0247] The liquid-crystalline media according to the invention preferably comprise one or more dielectrically neutral compounds (preferably having a dielectric anisotropy in the range from −1.5 to 3), preferably selected from the compounds of the formulae VI, VII, VIII and IX.

[0248] In the present application, elements all include their respective isotopes. In particular, one or more H may be replaced by D in a compound, and this is also particularly preferred in some embodiments. The corresponding high degree of deuteration of the corresponding compound for example enables detection and identification of the compound. This is very helpful in some cases, particularly in the case of compounds of formula I.

[0249] In this application

[0250] Alkyl particularly preferably denotes straight-chain alkyl, in particular CH3-, C2H5-, n-C3H7-, n-C4H9- or n-C5H 11 -,and

[0251] Alkenyl particularly preferably represents CH2=CH-, E-CH3-CH=CH-,

[0252] CH2=CH-CH2-CH2-, E-CH3-CH=CH-CH2-CH2- or E-(n-C3H7)-CH=CH-.

[0253] In a preferred embodiment of the invention, the medium according to the invention comprises in each case one or more compounds of the formula VI selected from the compounds of the formulae VI-1 and VI-2, preferably one or more compounds of the formula VI-2, and most preferably one or more compounds of each of the formula VI-1 and one or more compounds of the formula VI-2,

[0254]

[0255]

[0256] wherein the parameters have the respective meanings given above under formula VI, and preferably

[0257] In Formula VI-1

[0258] R 61 and R 62 Each independently represents a methoxy group, an ethoxy group, a propoxy group, a butoxy group or a pentoxy group, preferably an ethoxy group, a butoxy group or a pentoxy group, more preferably an ethoxy group or a butoxy group, and most preferably a butoxy group.

[0259] In Formula VI-2

[0260] R 61 Preferably, it represents 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

[0261] R 62 represents an unsubstituted alkyl radical having 1 to 7 C atoms, preferably having 2 to 5 C atoms, or an unsubstituted alkoxy radical having preferably 1 to 6 C atoms, particularly preferably having 2 or 4 C atoms, and most preferably ethoxy, and

[0262] In a preferred embodiment of the invention, the medium according to the invention comprises in each case one or more compounds of the formula VII selected from the compounds of the formulae VII-1 to VII-3, preferably one or more compounds of each of the formula VII-1 and one or more compounds of the formula VII-2,

[0263]

[0264] wherein the parameters have the respective meanings given above under formula VII, and preferably

[0265] R 71 Preferably, it represents 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

[0266] R 72 represents an unsubstituted alkyl radical having 1 to 7 C atoms, preferably having 2 to 5 C atoms, or an unsubstituted alkoxy radical preferably having 1 to 6 C atoms, particularly preferably having 2 or 4 C atoms, and most preferably an ethoxy radical,

[0267] In a preferred embodiment of the invention, the media according to the invention comprise in each case one or more compounds of the formula VI-1 selected from the following compounds:

[0268]

[0269] In a preferred embodiment of the invention, the media according to the invention comprise in each case one or more compounds of the formula VI-2 selected from the following compounds:

[0270]

[0271] In a preferred embodiment of the invention, the media according to the invention comprise in each case one or more compounds of the formula VII-1 selected from the following compounds:

[0272]

[0273]

[0274] In a preferred embodiment of the invention, the media according to the invention comprise in each case one or more compounds of the formula VII-2 selected from the following compounds:

[0275]

[0276] In addition to the compounds of formula I or preferred subformulae thereof, the medium according to the invention preferably also contains one or more compounds (preferably dielectrically neutral) selected from the compounds of formulae VI and VII, preferably in a total concentration in the range of 5% or more to 90% or less, preferably 10% or more to 80% or less, particularly preferably 20% or more to 70% or less.

[0277] In a preferred embodiment of the invention, the media according to the invention comprise in each case one or more compounds of the formula VIII selected from the compounds of the formulae VIII-1 to VIII-3, preferably one or more compounds of each of the formula VIII-1 and / or one or more compounds of the formula VIII-3,

[0278]

[0279] wherein the parameters have the respective meanings given above under formula VIII, and preferably

[0280] R 81 represents 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

[0281] R 82 represents an unsubstituted alkyl group having 1 to 7 C atoms (preferably having 1 to 5 C atoms) or an unsubstituted alkoxy group having 1 to 6 C atoms.

[0282] In Formulas VIII-1 and VIII-2, R 82 Preferably it denotes alkoxy having 2 or 4 C atoms, and most preferably ethoxy and in formula VIII-3 it preferably denotes alkyl, preferably methyl, ethyl or n-propyl, most preferably methyl.

[0283] In a further preferred embodiment, the medium comprises one or more compounds of formula IV,

[0284] One or more compounds of formula IV

[0285]

[0286] in

[0287] R 41 represents an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms, preferably n-alkyl radical, particularly preferably one having 2, 3, 4 or 5 C atoms, and

[0288] R 42 represents unsubstituted alkyl having 1-7 C atoms, unsubstituted alkenyl having 2-7 C atoms, or unsubstituted alkoxy having 1-6 C atoms (all preferably having 2-5 C atoms), unsubstituted alkenyl having 2-7 C atoms (preferably having 2, 3 or 4 C atoms), more preferably vinyl or 1-propenyl and in particular vinyl.

[0289] In a particularly preferred embodiment, the medium comprises one or more compounds of the formula IV selected from the compounds of the formulae IV-1 to IV-4, preferably the formula IV-1,

[0290]

[0291] in

[0292] Alkyl and alkyl' independently of one another denote an alkyl group having 1 to 7 C atoms, preferably having 2 to 5 C atoms,

[0293] 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,

[0294] Alkoxy is an alkoxy group having 1 to 5 C atoms, preferably having 2 to 4 C atoms.

[0295] In a particularly preferred embodiment, the medium according to the invention comprises one or more compounds of the formula IV-1 and / or one or more compounds of the formula IV-2.

[0296] In a further preferred embodiment, the medium comprises one or more compounds of formula V.

[0297] The medium according to the invention preferably comprises the following compounds in the indicated total concentrations:

[0298] 1-60 wt% of one or more compounds selected from the compounds of formula I, and

[0299] 5-60 wt% of one or more compounds of formula II, preferably selected from compounds of formula II-1 and II-2, and / or

[0300] 5-25 wt% of one or more compounds of formula III, and / or

[0301] 5-45 wt% of one or more compounds of formula IV, and / or

[0302] 5-25 wt% of one or more compounds of formula V, and / or

[0303] 5-25 wt% of one or more compounds of formula VI, and / or

[0304] 4-20 wt% of one or more compounds of formula VII, and / or

[0305] 0-30 wt% of one or more compounds of formula VIII, preferably selected from compounds of formula VIII-1 and VIII-2, and / or

[0306] 4-60 wt% of one or more compounds of formula IX,

[0307] The total content of all compounds of formulae S and I to IX present in the medium is preferably 95% or more, and more preferably 100%.

[0308] The latter condition is preferred for all media according to the present application.

[0309] In a further preferred embodiment, in addition to compounds of formula S or preferred subformulae thereof, and / or formula I or preferred subformulae thereof and compounds of formula VI and / or VII and / or VIII and / or IX, the medium according to the invention preferably also contains one or more compounds (preferably dielectrically neutral) selected from compounds of formulae IV and V, preferably in a total concentration in the range of 5% or more to 90% or less, preferably 10% or more to 80% or less, particularly preferably 20% or more to 70% or less.

[0310] In a particularly preferred embodiment, the medium according to the invention comprises

[0311] One or more compounds of formula II, in a total concentration ranging from 5% or more to 50% or less, preferably from 10% or more to 40% or less, and / or

[0312] One or more compounds of formula VII-1, in a total concentration ranging from 5% or more to 30% or less, and / or

[0313] One or more compounds of Formula VII-2, with the total concentration ranging from 3% or more to 30% or less.

[0314] Preferably, the concentration of the compound of formula S in the medium according to the present invention ranges from 1% or more to 60% or less, more preferably from 5% or more to 40% or less, most preferably from 8% or more to 35% or less.

[0315] Preferably, the concentration of the compound of formula I (if present) in the medium according to the present invention ranges from 1% or more to 60% or less, more preferably from 5% or more to 40% or less, most preferably from 8% or more to 35% or less.

[0316] In a preferred embodiment of the invention, the medium comprises one or more compounds of formula I (preferably selected from formula I-1 and I-2) and one or more compounds of formula I (preferably one or more compounds of formula I-1 and / or I-2).

[0317] In a preferred embodiment of the present invention, the concentration of the compound of formula II in the medium ranges 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.

[0318] In a preferred embodiment of the present invention, the concentration of the compound of formula VII in the medium is in the range of 2% or more to 50% or less, more preferably 5% or more to 40% or less, more preferably 10% or more to 35% or less, and most preferably 15% or more to 30% or less.

[0319] In a preferred embodiment of the present invention, the concentration of the compound of formula VII-1 in the medium ranges from 1% or more to 40% or less, more preferably 2% or more to 35% or less, or alternatively 15% or more to 25% or less.

[0320] In a preferred embodiment of the present invention, if present, the concentration of the compound of formula VII-2 in the medium ranges 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.

[0321] The invention also relates to an electro-optical display or electro-optical component containing a liquid crystal medium according to the invention. Preferably, it is based on the VA, ECB, IPS or FFS effect, more preferably an electro-optical display based on the VA, IPS or FFS effect, and in particular those addressed by an active matrix addressing device.

[0322] The present invention therefore 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 preparing a liquid-crystalline medium according to the invention, characterized in that one or more compounds of the formula I are mixed with one or more compounds of the formula II (preferably with one or more compounds of the sub-formulae II-1 and / or II-2) and / or with one or more compounds of the formula VII (preferably with one or more compounds of the sub-formulae VII-1 and / or VII-2), particularly preferably with one or more compounds of different formulae from two or more, preferably three or more of those formulae, and very particularly preferably with compounds from all four of these formulae II-1, II-2, VII-1 and VII-2, and with one or more further compounds (preferably selected from the group consisting of compounds of the formulae IV and V), more preferably with one or more compounds of both the formulae IV and V.

[0323] In a further preferred embodiment, the medium comprises one or more compounds of formula IV selected from compounds of formula IV-2 and IV-3,

[0324]

[0325] in

[0326] Alkyl and alkyl' independently of one another denote an alkyl group having 1 to 7 C atoms, preferably having 2 to 5 C atoms,

[0327] Alkoxy is an alkoxy group having 1 to 5 C atoms, preferably having 2 to 4 C atoms.

[0328] In a further preferred embodiment, the medium comprises one or more compounds of formula V selected from the group consisting of compounds of formulae V-1 to V-5, preferably compounds of formula V-1,

[0329]

[0330] wherein the parameters have the meanings given above under formula V and (F) 0 / 1 means F or H, and preferably

[0331] R 51 represents an alkyl group having 1 to 7 C atoms or an alkenyl group having 2 to 7 C atoms, and

[0332] R 52represents an alkyl group having 1 to 7 C atoms, an alkenyl group having 2 to 7 C atoms or an alkoxy group having 1 to 6 C atoms, preferably an alkyl group or an alkenyl group, particularly preferably an alkyl group, and preferably

[0333] In formula V-1

[0334] R 51 represents an alkenyl group having 2 to 7 C atoms, preferably 2 C atoms and

[0335] R 52 represents an alkyl group having 1 to 7 C atoms, preferably 1 C atom and

[0336] In formula V-3

[0337] R 51 represents an alkyl group having 1 to 7 C atoms, preferably 1 C atom and

[0338] R 52 represents an alkenyl group having 2 to 7 C atoms or an alkoxy group having 1 to 6 C atoms, preferably an alkenyl group having 4 or 5 C atoms, preferably -(CH2)2-CH=CH2, -(CH2)2-CH=CH-CH3, particularly preferably -(CH2)2-CH=CH-CH3,

[0339] In formula V-4

[0340] R 51 represents an alkyl group having 1 to 7 C atoms, preferably an ethyl group or a n-propyl group, and

[0341] R 52 represents an alkyl group having 1 to 7 C atoms, preferably ethyl, n-propyl, n-butyl or n-pentyl, or an alkenyl group having 2 to 7 C atoms, preferably vinyl, and

[0342] In formula V-5

[0343] R 51 represents an alkyl group having 1 to 7 C atoms or an alkenyl group having 2 to 7 C atoms, preferably n-propyl or n-pentyl, and

[0344] R 52 represents an alkyl group having 1 to 7 C atoms, preferably n-propyl or n-pentyl.

[0345] In a further preferred embodiment, the medium comprises one or more compounds of formula V-1 selected from compounds of formula V-1a and V-1b,

[0346]

[0347] in

[0348] Alkyl and alkyl' independently of one another denote an alkyl radical having 1 to 7 C atoms, preferably having 2 to 5 C atoms, and

[0349] Alkenyl is an alkenyl radical having 2 to 7 C atoms, preferably having 2 to 5 C atoms.

[0350] Furthermore, the present invention relates to a method for reducing the wavelength dispersion of the birefringence of a liquid crystal medium, which comprises one or more compounds of formula II, optionally one or more compounds selected from the group consisting of compounds of formulae VII-1 and VII-2 and / or one or more compounds of formula IV and / or one or more compounds of formula V, characterized in that one or more compounds of formula I are used in the medium.

[0351] Besides the compounds of the formulae I to V, further constituents may also be present, for example in amounts of up to 45%, but preferably up to 35%, in particular up to 10%, of the overall mixture.

[0352] In a preferred embodiment, the liquid-crystalline media according to the invention comprise in total, based on the mixture as a whole:

[0353] 1% or more to 50% or less, preferably 2% or more to 35% or less, particularly preferably 3% or more to 25% or less of a compound of formula S,

[0354] 1% or more to 20% or less, preferably 2% or more to 15% or less, particularly preferably 3% or more to 12% or less of the compound of formula I,

[0355] 20% or more to 50% or less, preferably 25% or more to 45% or less, particularly preferably 30% or more to 40% or less of the compounds of formula II and / or III, and

[0356] 0% or more to 35% or less, preferably 2% or more to 30% or less, particularly preferably 3% or more to 25% or less of compounds of formula IV and / or V, and

[0357] 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 formula VI and / or VII and / or VIII and / or IX.

[0358] The liquid-crystalline media according to the invention may comprise one or more chiral compounds.

[0359] Particularly preferred embodiments of the present invention satisfy one or more of the following conditions:

[0360] The acronyms (abbreviations) are explained in Tables A to C and illustrated by examples in Table D.

[0361] Preferably, the medium according to the invention satisfies one or more of the following conditions.

[0362] i. The liquid crystal medium has a birefringence of 0.060 or more, particularly preferably 0.070 or more.

[0363] ii. The liquid crystal medium has a birefringence of 0.200 or less, particularly preferably 0.180 or less.

[0364] iii. The liquid crystal medium has a birefringence ranging from 0.090 or more to 0.120 or less.

[0365] iv. the liquid crystal medium comprises one or more particularly preferred compounds of formula I-2. v. the total concentration of the compounds of formula IV in the mixture as a whole is 25% or more, preferably 30% or more, and preferably in the range of 25% or more to 49% or less, particularly preferably in the range of 29% or more to 47% or less, and very particularly preferably in the range of 37% or more to 44% or less.

[0366] vi. the liquid crystal medium comprises one or more compounds of formula IV selected from the group consisting of CC-nV and / or CC-n-Vm and / or CC-VV and / or CC-V-Vn and / or CC-nV-Vm, 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 24% or less, particularly preferably up to 30% or less.

[0367] vii. The medium comprises a compound of formula CC-nV, preferably CC-3-V, preferably at a concentration of 1% or more to 60% or less, more preferably at a concentration of 3% or more to 35% or less.

[0368] viii. The total concentration of the compound of formula CC-3-V in the entire mixture is preferably 15% or less, preferably 10% or less or 20% or more, preferably 25% or more.

[0369] ix. The total concentration of the compound of formula Y-nO-Om in the entire mixture is 2% or more to 30% or less, preferably 5% or more to 15% or less.

[0370] x. The total concentration of the compound of formula CY-n-Om in the entire mixture is 5% or more to 60% or less, preferably 15% or more to 45% or less.

[0371] xi. The total concentration of compounds of formula CCY-n-Om and / or CCY-nm, preferably CCY-n-Om, in the entire mixture is 5% or more to 40% or less, preferably 1% or more to 25% or less.

[0372] xii. The total concentration of the compound of formula CLY-n-Om in the entire mixture is 5% or more to 40% or less, preferably 10% or more to 30% or less.

[0373] xiii. The liquid crystal medium comprises one or more compounds of formula IV, preferably formula 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.

[0374] xiv. The liquid crystal medium comprises one or more compounds of formula V, preferably formula 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 30% or less.

[0375] xv. The total concentration of the compound of formula CCP-Vm, preferably CCP-V-1, in the whole mixture is preferably 5% or more to 30% or less, preferably 15% or more to 25% or less. xvi. The total concentration of the compound of formula CCP-V2-m, preferably CCP-V2-1, in the whole mixture is preferably 1% or more to 15% or less, preferably 2% or more to 10% or less.

[0376] The invention furthermore relates to an electro-optical display with active addressing based on the VA, ECB, IPS, FFS or UB-FFS effect, characterised in that it contains a liquid-crystalline medium according to the invention as dielectric.

[0377] The liquid crystal mixture preferably has a nematic phase having a width of at least 70 degrees.

[0378] The rotational viscosity γ1 is preferably 80 mPa·s or less, preferably 60 mPa·s or less and particularly 50 mPa·s or less.

[0379] The mixtures according to the invention are suitable for all IPS and FFS-TFT applications using dielectrically positive liquid-crystalline media, for example SB-FFS.

[0380] The liquid-crystalline media according to the invention preferably consist almost entirely of 4 to 18, in particular 5 to 15 and particularly preferably 12 or fewer compounds. These are preferably selected from the compounds of the formulae S, I, II, III, IV, V, VI, VII, VIII and IX.

[0381] 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.

[0382] In a preferred embodiment, the liquid-crystalline media according to the invention consist predominantly, preferably essentially and most preferably almost completely of compounds which do not contain cyano groups.

[0383] In a preferred embodiment, the liquid-crystal media according to the invention comprise compounds selected from the group consisting of compounds of the formulae I, II and III, IV and V and VI to IX, preferably compounds selected from the group consisting of compounds of the formulae I-1 and I-2, II (preferably selected from II-1 and II-2), III (preferably selected from III-1 and III-2), IV, V, VII (preferably selected from VII-1 and VII-2), VIII and IX; they preferably consist predominantly, particularly preferably essentially and very particularly preferably almost completely of compounds of the said formulae.

[0384] The liquid-crystalline media according to the invention preferably have in each case at least a nematic phase of -10°C or lower to 70°C or higher, particularly preferably -20°C or lower to 75°C or higher, very particularly preferably -30°C or lower to 80°C or higher and most preferably -40°C or lower to 85°C or higher.

[0385] The expression "having a nematic phase" here means on the one hand that at low temperatures no smectic phase and no crystallization are observed at the corresponding temperature, and on the other hand no clearing occurs on heating from the nematic phase. The investigations at low temperatures are carried out in a flow viscometer at the corresponding temperature and checked by storage in a test cell with a cell thickness corresponding to an electro-optical application of at least 100 hours. If the storage stability at a temperature of -20°C in a corresponding test cell is 1,000 hours or more, the medium is considered to be stable at this temperature. At temperatures of -30°C and -40°C, the corresponding times are 500 hours and 250 hours, respectively. At high temperatures, the clearing point is measured in a capillary by conventional methods.

[0386] In a preferred embodiment, the liquid crystal media according to the invention are characterized by optical anisotropy values ​​in the moderate to low range. The birefringence values ​​are preferably in the range of 0.075 or more to 0.130 or less, particularly preferably in the range of 0.085 or more to 0.120 or less, and very particularly preferably in the range of 0.090 or more to 0.115 or less.

[0387] In this embodiment, the liquid-crystal medium according to the present invention has a positive dielectric anisotropy and a relatively high absolute value of the dielectric anisotropy Δε, which is preferably in the range of 2.0 or more, preferably 3.0 or more, more preferably 4.0 or more to 15 or less, more preferably to 10 or less, more preferably 4.0 or more to 10 or less, particularly preferably 5.0 or more to 9.0 or less, and very particularly preferably 6.0 or more to 8.0 or less.

[0388] The liquid-crystalline media according to the invention preferably have relatively low threshold voltage (V0) values ​​ranging from 1.0 V or more to 2.0 V or less, preferably 1.2 V or more to 1.8 V or less, particularly preferably 1.3 V or more to 1.5 V or less.

[0389] In a further preferred embodiment, the liquid-crystalline media according to the invention preferably have a relatively high average dielectric constant value (ε av. ≡(ε || +2ε ⊥ ) / 3), which is preferably in the range of 4.0 or more to 10.0 or less, preferably 5.0 or more to 9.0 or less, more preferably to 8.0 or less.

[0390] Furthermore, the liquid-crystalline media according to the invention have high VHR values ​​in a liquid-crystal cell.

[0391] In freshly filled boxes at 20° C. or 25° C., these values ​​of VHR in the boxes are greater than or equal to 95%, preferably greater than or equal to 97%, particularly preferably greater than or equal to 98% and very particularly preferably greater than or equal to 99%, and after 5 minutes in an oven at 100° C., in the boxes, these are greater than or equal to 90%, preferably greater than or equal to 93%, particularly preferably greater than or equal to 96% and very particularly preferably greater than or equal to 98%.

[0392] 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.

[0393] These preferred values ​​for the individual physical properties are preferably also maintained in each case by combining the media according to the invention with one another.

[0394] In this application, unless expressly stated otherwise, the term "compound" also written as "compound(s)" refers to both one and a plurality of compounds.

[0395] In a preferred embodiment, the liquid-crystalline medium according to the invention comprises:

[0396] one or more compounds of formula STA, and

[0397] one or more compounds of formula I, and / or

[0398] one or more compounds of formula II, preferably selected from the group consisting of compounds of formula PUQU-nF, CDUQU-nF, APUQU-nF and PGUQU-nF, and / or

[0399] One or more compounds of formula III, preferably selected from the group consisting of compounds of formula CCP-n-OT, CCG-n-OT, CLP-nT, CGG-nF and CGG-n-OD, and / or

[0400] One or more compounds of formula IV, preferably selected from the group consisting of compounds of formula CC-nV, CC-n-Vm, CC-nm, and CC-VV, and / or

[0401] One or more compounds of formula V, preferably selected from the group consisting of compounds of formula CCP-nm, CCP-Vm, CCP-V2-m, CLP-Vn, CCVC-nV, and CGP-nm and / or

[0402] One or more compounds of formula VI, preferably selected from compounds of formula Yn-Om, Y-nO-Om and / or CY-n-Om, selected from compounds of formula Y-3-O1, Y-4O-O4, CY-3-O2, CY-3-O4, CY-5-O2 and CY-5-O4, and / or

[0403] One or more compounds of formula CCGU-nF, and / or

[0404] One or more compounds of formula PPGU-nF, and / or

[0405] One or more compounds of formula DPGU-nF, and / or

[0406] One or more compounds of formula CDUQU-nF, and / or

[0407] One or more compounds of formula APUQU-nF, and / or

[0408] One or more compounds of formula PGUQU-nF, and / or

[0409] One or more compounds of formula CCVC-nV, and / or

[0410] Optionally, preferably necessarily, one or more compounds of formula VII-1, preferably selected from the compounds of formula CCY-nm and CCY-n-Om, preferably formula CCY-n-Om, preferably selected from the compounds of formula CCY-3-O2, CCY-2-O2, CCY-3-O1, CCY-3-O3, CCY-4-O2, CCY-3-O2 and CCY-5-O2, and / or

[0411] Optionally, preferably necessarily, one or more compounds of formula VII-2, preferably of formula CLY-n-Om, preferably selected from compounds of formula CLY-2-O4, CLY-3-O2, CLY-3-O3, and / or

[0412] One or more compounds of formula VIII, preferably selected from the compounds of formula CZY-n-On and CCOY-nm and / or

[0413] One or more compounds of formula IX, preferably formula PYP-nm and / or

[0414] Optionally, preferably necessarily, one or more compounds of the formula IV, preferably selected from the compounds of the formulae CC-nV, CC-n-Vm and CC-nV-Vm, preferably selected from the compounds of the formulae CC-3-V, CC-3-V1, CC-4-V, CC-5-V and CC-VV, particularly preferably selected from the compounds of the formulae CC-3-V, CC-3-V1, CC-4-V and CC-VV, very particularly preferably the compound CC-3-V, and optionally additionally one or more compounds selected from the compounds of the formulae CC-4-V and / or CC-3-V1 and / or CC-VV, and / or

[0415] Optionally, preferably necessarily, one or more compounds of formula V, preferably formula CCP-V-1 and / or CCP-V2-1.

[0416] In a particularly preferred embodiment of the invention, the media according to the invention comprise one or more compounds of the formula IX.

[0417] The compounds of the formula IX are also highly suitable as stabilizers in liquid crystal mixtures, especially in the case where p=q=1 and ring A 9 =1,4-phenylene. In particular, they stabilize the VHR of the mixture against UV exposure.

[0418] In a preferred embodiment, the medium according to the invention comprises one or more compounds of the formula IX, which are selected from one or more compounds of the formulae IX-1 to IX-4, very particularly preferably the formulae IX-1 to IX-3, most preferably the formula IX-1

[0419]

[0420]

[0421] where the parameters have the meanings given under formula IX.

[0422] In a further preferred embodiment, the medium comprises one or more compounds of the formula IX-3, preferably compounds of the formula IX-3-a,

[0423]

[0424] in

[0425] Alkyl and alkyl' independently of one another denote an alkyl group having 1 to 7 C atoms, preferably having 2 to 5 C atoms.

[0426] In case compounds of formula IX are used in the liquid-crystalline media according to the present application, they are preferably present in a concentration of 20% or less, more preferably 10% or less and most preferably 5% or less, and for individual, i.e. (homologous) compounds, the preferred concentration is 10% or less and more preferably 5% or less.

[0427] For the present invention, the following definitions apply to the description of the components of the compositions in each case, unless otherwise stated:

[0428] - "comprising": the concentration of the ingredient in question in the composition is preferably 5% or more, particularly preferably 10% or more, very particularly preferably 20% or more,

[0429] - "essentially consists of": the concentration of the ingredient in question in the composition is preferably 50% or more, particularly preferably 55% or more and very particularly preferably 60% or more,

[0430] - "essentially consists of": the concentration of the ingredient in question in the composition is preferably 80% or more, particularly preferably 90% or more and very particularly preferably 95% or more, and

[0431] - "consists almost entirely of": the concentration of the ingredient in question in the composition is preferably 98% or more, particularly preferably 99% or more and very particularly preferably 100.0%.

[0432] This applies to the medium as a composition with its ingredients (which may be components and compounds) and also to the components with its ingredients (compounds). Only when it comes to the concentration of the individual compounds relative to the entire medium does the term "comprising" mean that the concentration of the compound in question is preferably 1% or more, particularly preferably 2% or more, very particularly preferably 4% or more.

[0433] For the present invention, "≤" means less than or equal to, preferably less than, and "≥" means greater than or equal to, preferably greater than.

[0434] For the present invention,

[0435]

[0436] represents trans-1,4-cyclohexylene,

[0437]

[0438] represents 1,4-cyclohexylene, preferably trans-1,4-cyclohexylene, and

[0439]

[0440] It represents 1,4-phenylene.

[0441] For the present invention, the expression "dielectrically positive compound" refers to compounds having a Δε>1.5, the expression "dielectrically neutral compound" refers to those in which -1.5≤Δε≤1.5 and the expression "dielectrically negative compound" refers to those in which Δε<-1.5 (all at a temperature of 20°C and a frequency of 1 kHz). The dielectric anisotropy of the compounds here is determined by dissolving 10% of the compound in a liquid crystal host and measuring the capacitance of the resulting mixture in each case at 1 kHz in at least one test cell with a homeotropic surface alignment and with a planar surface alignment with a cell thickness of 20 μm. The measuring voltage is generally between 0.5 V and 1.0 V, but is always below the capacitance threshold of the respective liquid crystal mixture under investigation. The host mixture for the dielectrically positive and dielectrically neutral compounds is ZLI-4792 and the host mixture for the 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 bulk mixture after addition of the compound to be investigated and extrapolated to 100% of the compound employed. The compound to be investigated is dissolved in the bulk mixture in an amount of 10%. If the solubility of the substance is too low for this purpose, the concentration is halved stepwise until the investigation can be carried out at the desired temperature.

[0442] If desired, the liquid crystal medium according to the invention may also contain other additives in the usual amounts, such as stabilizers and / or pleochroism, for example dichroic dyes and / or chiral additives. The amount of these additives employed is preferably 0% or more to 10% or less in total, 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. When specifying the concentration and concentration range of the liquid crystal compound in the liquid crystal medium, the concentration of these and similar additives is generally not taken into account.

[0443] In a preferred embodiment, the liquid-crystalline medium according to the invention comprises a polymer precursor comprising one or more reactive compounds, preferably reactive mesogens, and, if desired, further additives in the usual amounts, such as polymerization initiators and / or polymerization moderators. The amount of these additives employed is in total 0% or more to 10% or less, preferably 0.1% or more to 2% or less, based on the amount of the entire mixture. The concentrations of these and similar additives are not taken into account when specifying the concentrations and concentration ranges of the liquid-crystalline compounds in the liquid-crystalline medium.

[0444] The composition is composed of a variety of compounds, preferably 3 or more to 30 or less, particularly preferably 6 or more to 20 or less and very particularly preferably 10 or more to 16 or less types of compounds, which are mixed in a conventional manner. Usually, the components of the desired amount used in a smaller amount are dissolved in the components constituting the main components of the mixture. This is advantageously carried out at an elevated temperature. If the selected temperature is higher than the clearing point of the main component, it is particularly easy to observe that the dissolving operation is completed. However, the liquid crystal mixture can also be prepared in other conventional ways, for example using premixing or by a so-called "multi-bottle system".

[0445] The mixtures according to the invention exhibit a very broad nematic phase range with a clearing point at 65° C. or higher, very favorable capacitance thresholds, relatively high voltage holding ratio (VHR) values ​​and very good low temperature stability at both −30° C. and −40° C. Furthermore, the mixtures according to the invention are characterized by a low rotational viscosity γ1.

[0446] It is self-evident to the person skilled in the art that the media according to the invention for VA, IPS, FFS or PALC displays may also comprise compounds in which, for example, H, N, O, Cl, F have been replaced by the corresponding isotopes.

[0447] The structure of the liquid-crystal display according to the invention corresponds to a general geometry, as described, for example, in EP-A 0 240 379.

[0448] The liquid-crystalline phases according to the invention can be modified by suitable additives in such a way that they can be employed in any type of IPS and FFS LCD displays, for example those which have been disclosed to date.

[0449] Table E below indicates possible dopants that can be added to the mixtures according to the invention. If the mixture comprises one or more dopants, it or they are employed in an amount of 0.01% to 4%, preferably 0.1% to 1.0%.

[0450] Stabilizers which may be added to the mixture according to the invention, for example, preferably in amounts of 0.01% to 6%, in particular 0.1% to 3%, are shown in Table F below.

[0451] For the purposes of the present invention, unless expressly stated otherwise, all concentrations are stated as percentages by weight and relate to the respective entire mixture or to the mixture components also as a whole, unless expressly stated otherwise.In this context, the term "mixture" describes a liquid-crystalline medium.

[0452] Unless expressly stated otherwise, all temperature values ​​indicated in this application, such as melting point T(C,N), transition from smectic (S) phase to nematic (N) phase T(S,N) and clearing point T(N,I), are expressed in Celsius (°C) and all temperature differences are expressed in differential degrees (° or degrees), respectively.

[0453] For the purposes of the present invention, the term “threshold voltage” refers to the capacitive threshold ( V0 ), also called Freedericks-threshold, unless expressly stated otherwise.

[0454] All physical properties are and have been determined in accordance with "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status November 1997, Merck KGaA (Germany) and apply to a temperature of 20°C or 25°C, with Δn measured at 436nm, 589nm and 633nm and Δε measured at 1kHz, unless expressly stated otherwise in each case. Throughout this application, the standard temperature or reference temperature is 20°C.

[0455] The electro-optical properties, such as the threshold voltage (V0) (capacitive measurement) (as well as the switching behavior) were measured in a test cell made by Merck Japan. The measuring cell had a soda-lime glass substrate and was constructed in an ECB or VA configuration with a polyimide alignment layer (SE-1211 (mixing ratio 1:1) using diluent **26, both from Nissan Chemicals, Japan), which had been rubbed perpendicularly to each other and influenced the homeotropic alignment of the liquid crystal. The surface area of ​​the transparent, almost square ITO electrodes was 1 cm 2 .

[0456] Unless stated otherwise, no chiral dopants are added to the liquid-crystal mixtures used, but the latter are also particularly suitable for applications in which this type of doping is necessary.

[0457] The rotational viscosity was measured using the rotating permanent magnet method and the flow viscosity was measured in a modified Ubbelohde viscometer. For the liquid crystal mixtures ZLI-2293, ZLI-4792 and MLC-6608 (all products from Merck KGaA, Darms tadt (Germany)), the rotational viscosity values ​​measured at 20° C. were 161 mPa·s, 133 mPa·s and 186 mPa·s, respectively, and the flow viscosity values ​​(ν) were 21 mm·s, respectively. 2 ·s -1 , 14mm 2 ·s -1 and 27mm 2 ·s -1 .

[0458] The refractive index dispersion of a material may conveniently be characterized for practical purposes in the following manner, which is used throughout the application unless otherwise stated. The birefringence values ​​are determined at several fixed wavelengths at a temperature of 20°C or 25°C using a modified Abbe refractometer, with the homeotropically aligned surface in contact with the material on the side of the prism. The birefringence values ​​are determined at specific wavelength values ​​of 436 nm (selected spectral lines of a low pressure mercury lamp), 589 nm (the sodium "D" line), and 633 nm (the wavelength of a HE-Ne laser, which is used in combination with an attenuator / diffuser to prevent damage to the observer's eyes). In the following table, Δn is given at 589 nm and Δ(Δn) is given as Δ(Δn)=Δn(436 nm)-Δn(633 nm).

[0459] Unless explicitly stated otherwise, the following symbols are used:

[0460] V0 represents the threshold voltage, capacitive [V], at 20℃ or 25℃,

[0461] n e represents the extraordinary refractive index measured at 20°C or 25°C and 589nm,

[0462] n o represents the ordinary refractive index measured at 20°C or 25°C and 589nm,

[0463] △n represents the optical anisotropy measured at 20℃ or 25℃ and 589nm,

[0464] λ represents the wavelength λ[nm],

[0465] △n(λ) represents the optical anisotropy measured at 20℃ or 25℃ and wavelength λ,

[0466] ε ⊥ represents the dielectric polarizability perpendicular to the director at 20°C or 25°C and 1kHz,

[0467] ε || represents the dielectric polarizability parallel to the director at 20°C or 25°C and 1kHz,

[0468] △ε represents the dielectric anisotropy at 20℃ or 25℃ and 1kHz,

[0469] T(N,I) or cl.p. indicates the clearing point [℃],

[0470] ν represents the flow viscosity measured at 20°C or 25°C [mm 2 ·s -1 ],

[0471] γ1 is the rotational viscosity measured at 20°C or 25°C [mPa·s],

[0472] k 11 represents the elastic constant, the "slant" deformation at 20°C [pN],

[0473] k 22 Indicates the elastic constant, the "twist" deformation at 20℃ or 25℃ [pN],

[0474] k 33 Indicates the elastic constant, the "bending" deformation at 20℃ or 25℃ [pN],

[0475] LTS stands for the low temperature stability of the phase measured in a test cell,

[0476] VHR represents the voltage holding ratio at 20°C or 25°C.

[0477] △VHR represents the decrease in voltage holding ratio at 20℃ or 25℃, and

[0478] S rel Indicates the relative stability of VHR at 20℃ or 25℃,

[0479] The following examples explain the present invention, but do not limit it. However, they show the preferred mixture concept of the compounds to be used and their respective concentrations and their combinations with each other to those skilled in the art. In addition, the examples illustrate the properties and property combinations that can be obtained.

[0480] For the present invention and in the following examples, the structures of the liquid crystal compounds are indicated by acronyms, converted into chemical formulae according to the following Tables A to C. n H 2n+1 , C m H 2m+1 and C l H 2l+1 or C n H 2n, C m H 2m and C l H 2l is a straight chain alkyl or alkylene group, in each case, each having n, m and 1 C atoms. Preferably, n, m and 1 are independently 1, 2, 3, 4, 5, 6 or 7. Table A shows the code of the ring elements of the compound core, Table B lists the bridging unit, and Table C lists the symbolic meaning of the left-hand and right-hand end groups of the molecule. The acronym consists of the code of the ring element with an optional connecting group, followed by the first hyphen and the left-hand end group code, and the second hyphen and the right-hand end group code. Table D shows the exemplary structures of the compounds and their respective abbreviations.

[0481] Table A: Ring elements

[0482]

[0483]

[0484]

[0485] Table B: Bridge Unit

[0486]

[0487] Table C: End Groups

[0488]

[0489]

[0490] wherein n and m are each integers, and the three dots "..." are placeholders for other abbreviations from the table.

[0491] Besides the compounds of the formula I, the mixtures according to the invention preferably also comprise one or more of the compounds mentioned below.

[0492] The following abbreviations are used:

[0493] (n, m and l are each independently an integer, preferably 1-6, l may also be 0 and is preferably 0 or 2)

[0494] Table D

[0495] With high ε ⊥ Exemplary preferred compounds of formula I:

[0496]

[0497]

[0498] The additional compounds are

[0499]

[0500]

[0501] Exemplary preferred dielectric positive compounds

[0502]

[0503]

[0504]

[0505]

[0506]

[0507]

[0508]

[0509] Exemplary preferred dielectric neutral compounds

[0510]

[0511]

[0512]

[0513]

[0514]

[0515] Exemplary preferred dielectric negative compounds

[0516]

[0517]

[0518]

[0519]

[0520]

[0521]

[0522]

[0523]

[0524] Table E shows chiral dopants preferably employed in the mixtures according to the invention.

[0525] Table E

[0526]

[0527]

[0528]

[0529] In a preferred embodiment of the invention, the medium according to the invention comprises one or more compounds selected from the compounds of Table E.

[0530] Table F shows stabilizers which can preferably be employed in the mixtures according to the invention in addition to the compounds of the formula I. The parameter n here represents an integer in the range from 1 to 12. In particular, the phenolic derivatives shown can be employed as additional stabilizers, since they act as antioxidants.

[0531] Table F

[0532]

[0533]

[0534]

[0535]

[0536]

[0537] In a preferred embodiment of the invention, the media according to the invention comprise one or more compounds selected from the compounds of Table F, in particular one or more compounds selected from the compounds of the following two formulae.

[0538] Example

[0539] The following examples explain the present invention without limiting it in any way. However, the physical properties make it clear to those skilled in the art what kind of performance can be achieved and in which range they can be modified. In particular, the combination of multiple performances that can be preferably achieved is well defined for those skilled in the art.

[0540] Mixture Examples

[0541] The following are exemplary mixtures disclosed.

[0542] Example 1

[0543] The following mixture (M-1) was prepared and investigated.

[0544]

[0545] The mixture, mixture M-1, had a dielectric ratio (ε ⊥ / △ε),5.04mPa·s / pN(γ1 / k 11 ) ratio and is characterized by very good transmittance in FFS displays and shows very short response times.

[0546] 0.050% of STA-1-1 was added to the mixture M-1. The stability of the resulting mixture M-1.1 was investigated and found to be excellent.

[0547] Example 2

[0548] The following mixture (M-2) was prepared and investigated.

[0549]

[0550] The mixture, mixture M-2, had a dielectric ratio (ε ⊥ / △ε),4.02mPa·s / pN(γ1 / k 11 ) ratio and is characterized by very good transmittance in FFS displays and shows very short response times.

[0551] 0.050% of STA-1-1 was added to mixture M-2. The stability of the resulting mixture M-2.1 was investigated and found to be excellent.

[0552] Example 3

[0553] The following mixture (M-3) was prepared and investigated.

[0554]

[0555] The mixture, mixture M-3, had a dielectric ratio (ε ⊥ / △ε),4.05mPa·s / pN(γ1 / k 11 ) ratio and is characterized by very good transmittance in FFS displays and shows very short response times.

[0556] 0.050% of STA-1-1 was added to mixture M-3. The stability of the resulting mixture M-3.1 was investigated and found to be excellent.

[0557] Example 4

[0558] The following mixture (M-4) was prepared and investigated.

[0559]

[0560] The mixture, mixture M-4, had a dielectric ratio (ε ⊥ / △ε),5.88mPa·s / pN(γ1 / k 11 ) ratio and is characterized by very good transmittance in FFS displays and shows very short response times.

[0561] Example 5

[0562] The following mixture (M-5) was prepared and investigated.

[0563]

[0564] Note: tbd: to be determined

[0565] The mixture, mixture M-5, had a dielectric ratio (ε ⊥ / △ε),4.13mPa·s / pN(γ1 / k 11 ) ratio and is characterized by very good transmittance in FFS displays and shows very short response times.

[0566] Example 6

[0567] The following mixture (M-6) was prepared and investigated.

[0568]

[0569] Note: tbd: to be determined

[0570] The mixture, mixture M-6, had a dielectric ratio (ε ⊥ / △ε),4.92mPa·s / pN(γ1 / k 11 ) ratio and is characterized by very good transmittance in FFS displays and shows very short response times.

[0571] Example 7

[0572] The following mixture (M-7) was prepared and investigated.

[0573]

[0574] The mixture, mixture M-7, had a dielectric ratio (ε ⊥ / △ε), 6.79mPa·s / pN (γ1 / k 11 ) ratio and is characterized by very good transmittance in FFS displays and shows very short response times.

[0575] 0.020% and 0.050% respectively Added to mixture M-7. The stability of the resulting mixtures M-7.1 and M7.2 was investigated and found to be excellent.

[0576] Example 8

[0577] The following mixture (M-8) was prepared and investigated.

[0578]

[0579] Note: tbd: to be determined

[0580] The mixture, mixture M-8, had a dielectric ratio (ε ⊥ / △ε),7.25mPa·s / pN(γ1 / k 11 ) ratio and is characterized by very good transmittance in FFS displays and shows very short response times.

[0581] 0.050% Added to mixture M-8. The stability of the obtained mixture M-8.1 was investigated and found to be excellent.

[0582] Example 9

[0583] The following mixture (M-9) was prepared and investigated.

[0584]

[0585] Note: tbd: to be determined

[0586] The mixture, mixture M-9, had a dielectric ratio (ε) of 0.72 at 25°C. ⊥ / △ε),6.02mPa·s / pN(γ1 / k 11 ) ratio and is characterized by very good transmittance in FFS displays and shows very short response times.

[0587] 0.020% of Compound S was added to the mixture M-9. The stability of the obtained mixture M-9.1 was investigated and found to be excellent.

[0588] Example 10

[0589] The following mixture (M-10) was prepared and investigated.

[0590]

[0591] Note: tbd: to be determined

[0592] The mixture, mixture M-10, had a dielectric ratio (ε ⊥ / △ε),6.02mPa·s / pN(γ1 / k 11 ) ratio and is characterized by very good transmittance in FFS displays and shows very short response times.

[0593] 0.020% of Compound S was added to the mixture M-10. The stability of the obtained mixture M-10.1 was investigated and found to be excellent.

[0594] Embodiment 11

[0595] The following mixture (M-11) was prepared and investigated.

[0596]

[0597] Note: tbd: to be determined

[0598] The mixture, mixture M-11, has a beneficial dielectric ratio (ε ⊥ / △ε), good (γ1 / k 11 ) ratio and is characterized by very good transmittance in FFS displays and shows very short response times.

[0599] 0.020% of the compound Alternatively, STA-1-1 was added to the mixture M-11. The stability of the resulting mixtures M-11.1 and M-11.2 was investigated and found to be excellent.

[0600] Example 12

[0601] The following mixture (M-12) was prepared and investigated.

[0602]

[0603] Embodiment 13

[0604] The following mixture (M-13) was prepared and investigated.

[0605]

[0606] Embodiment 14

[0607] The following mixture (M-14) was prepared and investigated.

[0608]

[0609] These other three exemplary mixtures, mixtures M-12; M-13 and M-14, have beneficial dielectric ratios (ε ⊥ / △ε), good (γ1 / k 11 ) ratio and is characterized by very good transmittance in FFS displays and shows very short response times.

[0610] 0.020% of the compound Or STA-1-1 was added to each of the mixtures M-12, M-13 and M-14. The stability of the obtained mixtures M-12.1 and M-12.2; M-13.1 and M-13.2; and M-14.1 and M-14.2 was studied respectively, and it was found that the stability was excellent.

Claims

1. A liquid crystal medium, characterized in that It comprises one or more compounds of formula I in express express n represents 0 or 1, R 11 and R 12 Independently of one another, they represent alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 9 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 9 C atoms.

2. A medium according to claim 1, characterized in that It comprises one or more compounds of formula I, which are selected from compounds of formula I-1 and I-2: The parameters have the meanings given in claim 1.

3. A medium according to claim 2, characterized in that It comprises one or more compounds of formula I-1.

4. A medium according to at least one of claims 1 to 3, characterised in that It comprises one or more compounds selected from compounds of formula II and III: in R 2 represents an alkyl group, an alkoxy group, a fluorinated alkyl group or a fluorinated alkoxy group having 1 to 7 C atoms, an alkenyl group, an alkenyloxy group, an alkoxyalkyl group or a fluorinated alkenyl group having 2 to 7 C atoms, In each occurrence, they are expressed independently of each other L 21 and L 22 independently of each other represent H or F, X 2 represents halogen, halogenated alkyl or alkoxy having 1 to 3 C atoms or halogenated alkenyl or alkenyloxy having 2 or 3 C atoms, m represents 0, 1, 2 or 3, R 3 represents an alkyl group, an alkoxy group, a fluorinated alkyl group or a fluorinated alkoxy group having 1 to 7 carbon atoms, an alkenyl group, an alkenyloxy group, an alkoxyalkyl group or a fluorinated alkenyl group having 2 to 7 carbon atoms In each occurrence, independently of each other L 31 and L 32 independently of each other represent H or F, X 3 represents 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, -OCHF2, -O-CH2CF3, -O-CH=CF2, -O-CH=CH2 or -CF3, Z 3 represents -CH2CH2-, -CF2CF2-, -COO-, trans-CH=CH-, trans-CF=CF-, -CH2O- or a single bond, and n represents 0, 1, 2 or 3.

5. Liquid-crystalline medium according to at least one of claims 1 to 4, characterized in that It comprises one or more compounds selected from formula IV and V: in R 41 and R 42 Independently of one another, in claim 4, under formula II for R 2 The meaning indicated, Independently of each other, and if Appears twice, These also represent independently of each other Z 41 and Z 42 Independently of each other, and if Z 41 appears twice, these also independently represent -CH2CH2-, -COO-, trans-CH=CH-, trans-CF=CF-, -CH2O-, -CF2O-, -C≡C- or a single bond, p represents 0, 1 or 2, R 51 and R 52 Independently of each other, they have 41 and R 42 One of the meanings given, to If present, each represents independently of the other Z 51 To Z 53 each independently represents -CH2-CH2-, -CH2-O-, -CH=CH-, -C≡C-, -COO- or a single bond, and i and j each independently represent 0 or 1.

6. Liquid-crystalline medium according to at least one of claims 1 to 5, characterized in that It comprises one or more compounds selected from formulae VI to IX: in R 61 represents an unsubstituted alkyl group having 1 to 7 C atoms, an unsubstituted alkenyl group having 2 to 7 C atoms, an unsubstituted alkoxy group having 1 to 6 C atoms or an unsubstituted alkenyloxy group having 2 to 6 C atoms, R 62 represents an unsubstituted alkyl group having 1 to 7 C atoms, an unsubstituted alkoxy group having 1 to 6 C atoms or an unsubstituted alkenyloxy group having 2 to 6 C atoms, and l means 0 or 1, R 71 represents an unsubstituted alkyl group having 1 to 7 C atoms, or an unsubstituted alkenyl group having 2 to 7 C atoms, R 72 represents an unsubstituted alkyl group having 1 to 7 C atoms, an unsubstituted alkoxy group having 1 to 6 C atoms or an unsubstituted alkenyloxy group having 2 to 6 C atoms, express R 81 represents an unsubstituted alkyl group having 1 to 7 C atoms, or an unsubstituted alkenyl group having 2 to 7 C atoms, R 82 represents an unsubstituted alkyl group having 1 to 7 C atoms, an unsubstituted alkoxy group having 1 to 6 C atoms or an unsubstituted alkenyloxy group having 2 to 6 C atoms, preferably having 2, 3 or 4 C atoms, express Z 8 represents -(C=O)-O-, -CH2-O-, -CF2-O- or -CH2-CH2-, o means 0 or 1, R 91 and R 92 Independently of each other, the above 72 The meaning given, express p and q represent 0 or 1 independently of each other.

7. A medium according to at least one of claims 1 to 6, characterized in that The total concentration of the compound of formula I in the entire medium is from 1% or more to 60% or less.

8. The medium according to claim 1, characterized in that It comprises one or more compounds selected from the group consisting of formula CCVC-nV, CCGU-nF, PPGU-nF, DPGU-nF, CDUQU-nF and APUQU-nF, wherein n represents an integer of 1 to 6.

9. Medium according to at least one of claims 1 to 8, characterised in that, in addition to one or more compounds of formula I, it comprises one or more further stabilisers.

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

11. Display according to claim 10, characterized in that it is based on IPS or FFS mode.

12. A display according to claim 10 or 11, characterised in that it comprises an active matrix addressing device.

13. Display according to at least one of claims 10 to 12, characterized in that it is a mobile display.

14. Use of a medium according to at least one of claims 1 to 9 in an electro-optical display or in an electro-optical component.

15. Process for the preparation of a liquid-crystalline medium according to one or more of claims 1 to 9, characterised in that one or more compounds of the formula I are mixed with one or more additional mesogenic compounds and optionally stabilizers.

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