LCD media

Abstract

A liquid crystal medium is provided. The present invention relates to a liquid-crystalline medium having a nematic phase, which comprises one or more compounds of formula I and a negative dielectric component. TIFF2025526319000153.tif51166 (where the parameters have the meanings given in the text). It can be used in liquid crystal electro-optical devices, especially liquid crystal lenses. The mixtures have high optical anisotropy and high refractive index, which makes them suitable for high-speed switches using simultaneous dual-frequency addressing and combined with low power consumption.

Description

[Technical Field]

[0001] The present invention relates to novel liquid crystal media, in particular for use in liquid crystal electro-optical elements, and to these elements, in particular liquid crystal displays or optical lenses, using dual frequency addressing which is optimized for short response times combined with low power consumption. [Background technology]

[0002] Dielectric dispersion is the dependence of the dielectric constant of a dielectric material on the frequency of the applied electric field. Dual frequency liquid crystal (DFLC) materials or blends have a high dispersion in the dielectric anisotropy, i.e., the dielectric anisotropy Δε(f)=ε ∥ (f)-ε ⊥ (f) is frequency dependent, resulting in a crossover frequency f co changes sign, but Δε(f co )=0. In some DFLC materials, f co occurs at several kHz, and Δf co varies significantly over the range of 1 to 100 kHz at 20°C. In a DFLC cell, the LC molecules have a preferred direction (unit vector) along which they tend to orient, so f co By applying an electric field to the sample at either higher or lower frequencies, the director can be driven between homogeneous and homeotropic alignments. When an electric field is applied to the LC, it exerts a torque on the unit vector. Depending on the sign of the anisotropy, i.e., Δε>0 or Δε<0, this torque rotates the director, aligning it parallel or perpendicular to the field direction, respectively. Depending on the frequency of the applied electric field, the director realigns to either a homeotropic state (perpendicular to the substrate) or a planar state (parallel to the substrate). For lens applications based on dual-frequency nematic media, this allows control of not only the absolute value of the focal length, but also its sign.

[0003] The response time of a liquid crystal material is primarily driven by the value of the electric field at switch-on. However, switch-off depends on relaxation and can be much slower. In dual-frequency devices, the sign of the effective dielectric anisotropy can be reversed, allowing the switch-off phase to be actively driven by an electric signal. Short switching times can therefore be achieved. This is particularly interesting for materials with highly optimized optical properties, which are usually hardly compatible with the concept of fast-response mixtures.

[0004] Dual-frequency liquid crystal mixtures are typically composed of two categories of materials: compounds that exhibit positive dielectric anisotropy at low frequencies and compounds that exhibit negative dielectric anisotropy at high frequencies. Some materials for such mixtures have been published in several publications, such as Haiqing Xianyu, Shin-Tson Wu, and Chih-Lung Lin (2009) Dual Frequency Liquid Crystals: A Review, Liquid Crystals, Vol. 36, No. 6-7, pp. 717-726, DOI: 10.1080 / 02678290902755598 (Non-Patent Document 1). Jie Sun et al., Liquid Crystals, Vol. 36, No. 12, December 2009, pp. 1401-1408 (Non-Patent Document 2), describe polar nitriles and isothiocyanates as components of dual-frequency liquid crystals. These publications provide guidelines for preparing dual-frequency mixtures.

[0005] The crossover frequency is defined as the frequency at which the dielectric anisotropy changes sign. Lower crossover frequencies are usually preferred. These electro-optical properties of a two-frequency mixture should ideally be stable with temperature changes.

[0006] IPS and FFS displays using dielectrically positive liquid crystals are well known in the art and have been widely adopted for various types of displays, such as desktop monitors and television sets, as well as for mobile applications. However, recently, IPS and especially FFS displays using dielectrically negative liquid crystals have become widely adopted. The latter are sometimes referred to as UB-FFS (ultra bright FFS). Such displays are disclosed, for example, in U.S. Patent Application Publication No. 2013 / 0207038 (Patent Document 1). However, these displays using conventional dielectrically negative liquid crystals have the disadvantage of requiring higher operating voltages than displays using dielectrically positive liquid crystals.

[0007] Liquid crystal media used in HB-FFS and containing both dielectrically negative and dielectrically positive liquid crystal compounds, respectively, as mesogenic compounds, are disclosed, for example, in US Patent Application Publication No. 2013 / 0207038 (Patent Document 1).

[0008] Industrial applications in electro-optical displays and other devices require LC phases which must fulfill a number of requirements: here, chemical resistance to moisture, air and physical influences such as heat, radiation in the infrared, visible and ultraviolet ranges and direct current (DC) and alternating current (AC) electric fields is of particular importance.

[0009] Furthermore, commercially usable LC phases are required to have a liquid crystal mesophase in an appropriate temperature range and a low viscosity.

[0010] None of the series of compounds having liquid crystal mesophases disclosed so far includes a single compound that fulfills all of these requirements.To obtain a material that can be used as an LC phase, a mixture of 2 to 25, preferably 3 to 18, compounds is generally prepared.

[0011] In general, displays, i.e., displays based on these effects, also require as low an operating voltage as possible, and liquid-crystalline media are generally used that are composed primarily of liquid-crystalline compounds, all of which have the same sign of dielectric anisotropy and as high a dielectric anisotropy value as possible. Generally, neutral compounds are present in relatively small amounts at most, and, if possible, compounds with the opposite sign to the dielectric anisotropy of the medium are avoided. Thus, for example, in liquid-crystalline media with negative dielectric anisotropy for ECB or UB-FFS displays, compounds with negative dielectric anisotropy are predominantly used. Generally, the respective liquid-crystalline media employed consist primarily of liquid-crystalline compounds with negative dielectric anisotropy.

[0012] However, the media used in this application typically employ significant amounts of dielectrically positive and negative liquid crystal compounds. U.S. Patent Application Publication No. 2013 / 0207038 (Patent Document 1) discloses a liquid crystal medium for HB-FFS displays that proposes improving the performance of FFS displays using liquid crystals with positive dielectric anisotropy by additionally incorporating dielectrically negative liquid crystals. However, this requires compensating for the negative contribution of these compounds to the overall dielectric anisotropy of the resulting medium. This requires increasing the concentration of dielectrically positive materials, which leaves less room for the use of dielectrically neutral compounds as diluents in the mixture, or alternatively requires the use of compounds with stronger positive dielectric anisotropy. Both of these alternatives have the major drawback of increasing the response time of the liquid crystals in the display.

[0013] The phase range of the liquid crystal mixture must be sufficiently wide for the intended use of the device. The response time of the liquid crystal medium in the display must be as low as possible, especially for video, animation simulation, and game applications. This is particularly important for displays intended for television and 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 crystal medium, i.e., to achieve a medium with the lowest possible rotational viscosity. However, the results achieved here are insufficient for many applications, and therefore it would be desirable to find further optimization approaches.

[0014] Adequate stability of the medium against severe stresses, especially UV exposure and heating, can be crucial, especially for display applications in mobile and wearable devices such as mobile phones and AR / VR headsets.

[0015] In addition to their relatively low transmittance and their relatively long response time, the active matrix displays disclosed to date have further drawbacks, such as their relatively low contrast, their relatively high viewing angle dependence, the difficulty of reproducing gray levels in these displays, especially when viewed from oblique viewing angles, as well as their poor VHR (voltage holding ratio) and their poor lifetime. Desirable improvements in the transmittance of displays and their response times are required to improve their energy efficiency or their ability to render fast-moving images.

[0016] Thus, there remains a great demand for active matrix displays that have very high resistivity, at the same time a wide operating temperature range, short response times and relatively low threshold voltages, so that a variety of grey levels can be produced, and that have particularly good and stable VHR. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] US Patent Application Publication No. 2013 / 0207038 [Non-patent literature]

[0018] [Non-Patent Document 1] Haiqing Xianyu, Shin-Tson Wu and Chih-Lung Lin (2009) Dual frequency liquid crystals: a review, Liquid Crystals, Vol. 36, No. 6-7, pp. 717-726, DOI: 10.1080 / 02678290902755598 [Non-patent document 2] Jie Sun et al., Liquid Crystals, Volume 36, Issue 12, December 2009, Pages 1401-1408 Summary of the Invention [Problem to be solved by the invention]

[0019] The present invention has the object of providing liquid crystal mixtures for displays and optical lenses for monitor and television applications, but also for morphological applications such as, for example, phones, switchable light guides, AR / VR devices, glasses, navigation systems, etc., based on the VA, ECB, IPS or FFS effect. [Means for solving the problem]

[0020] Surprisingly, it has been found that when nematic liquid crystal media according to the present invention and the claims are used in these optical elements, it is possible to achieve liquid crystal devices with short response times, low threshold voltages, sufficiently broad nematic phases, favorable birefringence (Δn) and at the same time high transmittance, high contrast and good stability against degradation by heating and UV exposure.

[0021] This type of medium can be used in particular in electro-optical devices with dual frequency addressing.

[0022] The mixtures according to the invention exhibit a very wide nematic phase range with a clearing point above 70° C., very favorable values of the crossover frequency, relatively high values of retention and at the same time good low-temperature stability at −20° C. and −30° C. Furthermore, the mixtures according to the invention are characterized by a relatively high positive dielectric anisotropy at low frequencies. DETAILED DESCRIPTION OF THE INVENTION

[0023] The liquid-crystalline media according to the invention comprise:

[0024] a) one or more compounds of formula I, preferably dielectrically positive (1 kHz) compounds, preferably in a concentration in the range of 5% to 50%, more preferably in the range of 10% to 40%, particularly preferably in the range of 15% to 35%.

[0025] [ka]

[0026] During the ceremony, R 1 represents an alkyl group having 1 to 15 C atoms (wherein one or more CH groups contain a terminal C atom, and in this group, independently of one another, O or S atoms are not directly linked to one another, and are substituted with -C≡C-, -CH=CH-, [ka] -O-, -S-, -(CO)-O-, -O-(CO)-, in addition, one or more H atoms may be replaced by F or Cl) or H, [ka] Preferably [ka] represents [ka] Preferably [ka] represents Z 1 represents —C≡C—, —(CO)O— or —CF2O—, preferably —C≡C—, Z 2 represents a single bond, —(CO)O— or —CF2O—, preferably a single bond, L 11 , L 12 are independently H, F or Cl, preferably F; L 13 is H, CH3 or CH2CH3, preferably H, X 1 is -CN, -SCN, -OCF3 or F, preferably -CN or -SCN, n represents 1 or 2, preferably 1.

[0027] and b) one or more compounds selected from the group of formulae II, III and VI to IX, preferably dielectrically negative (1 kHz) compounds: Preferably, one or more compounds selected from II, III and VII, more preferably II and III.

[0028] [ka]

[0029] During the ceremony, R 21 and R 22 are each independently R 1 and preferably alkyl or alkoxy having 1 to 7 C atoms, alkenyl, alkenyloxy or alkoxyalkyl having 2 to 7 C atoms or C 3~5 -Cycloalkyl-(CH2)0~1 and Preferably R 21 is alkyl of 1 to 7 C atoms, alkenyl of 2 to 7 C atoms, cyclopentyl-(CH2)- or cyclopentyl, and R 22 is alkyl or alkoxy of 1 to 7 C atoms, [ka] Preferably TIFF2025526319000010.tif33166, n is independently 0 or 1;

[0030] [ka] represents L 3 is CH3, OCH3 or CH2CH3, [ka] Preferably [ka] represents R 31 and R 32 are each independently R 1 and preferably alkyl or alkoxy having 1 to 7 C atoms, alkenyl, alkenyloxy or alkoxyalkyl having 2 to 7 C atoms or C 3~5 -Cycloalkyl-(CH2) 0~1 -O-, most preferably alkoxy of 1 to 7 C atoms, cyclopentyl-O- or cyclopentyl-CH2-O-, Preferably R 32 is alkoxy having 1 to 7 C atoms,

[0031] R 61 are independently R1 and preferably an unsubstituted alkyl group having 1 to 7 C atoms, preferably a linear alkyl group, more preferably an n-alkyl group, most preferably propyl or pentyl, an unsubstituted alkenyl group having 2 to 7 C atoms, preferably a linear alkenyl group, particularly preferably an unsubstituted alkoxy group having 1 to 6 C atoms, an unsubstituted alkenyloxy group having 2 to 6 C atoms or C 3~5 -Cycloalkyl-(CH2) 0~1 represents R 62 are independently R 1 and preferably an unsubstituted alkyl group having 1 to 7 C atoms, an unsubstituted alkoxy group having 1 to 6 C atoms, 3~5 -cycloalkyloxy, C 3~5 - represents a cycloalkylmethoxy or an unsubstituted alkenyloxy group having 2 to 6 C atoms, and L 61 , L 62 are independently H or methyl, preferably H; l represents 0 or 1;

[0032] R 71 are independently R 1 and preferably an unsubstituted alkyl group having 1 to 7 C atoms, preferably a linear alkyl group, more preferably an n-alkyl group, most preferably propyl or pentyl, an unsubstituted alkenyl group having 2 to 7 C atoms, preferably a linear alkenyl group, particularly preferably having 2 to 5 C atoms, or 3~5 -Cycloalkyl-(CH2) 0~1 represents R 72 are independently R 1 and preferably 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 L 71 , L 72 are independently H or methyl, preferably H; [ka] represents

[0033] R 81 is R 1 and preferably an unsubstituted alkyl group having 1 to 7 C atoms, preferably a linear alkyl group, more preferably an n-alkyl group, most preferably propyl or pentyl, an unsubstituted alkenyl group having 2 to 7 C atoms, preferably a linear alkenyl group, particularly preferably having 2 to 5 C atoms, or 3~5 -Cycloalkyl-(CH2) 0~1 represents R 82 is R 1 and preferably 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, an unsubstituted alkenyloxy group having 2 to 6 C atoms, preferably having 2, 3 or 4 C atoms, or a C 3~5 -represents cycloalkyloxy, and L 81 , L 82 are independently H or methyl, preferably H; [ka] Preferably [ka] More preferably [ka] represents Z 8 represents -(CO)-O-, -CH2-O-, -CF2-O- or -CH2-CH2-, preferably -(CO)-O- or -CH2-O-, and o represents 0 or 1,

[0034] R 91 and R 92 are independently R 72 has the meaning given above, R 91 preferably denotes an alkyl group having 2 to 5 C atoms, preferably having 3 to 5 C atoms, R 92 preferably 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, [ka] represents, and p is 0 or 1.

[0035] The medium according to the invention preferably comprises one or more additional compounds selected from the group of compounds according to the following conditions c) to f):

[0036] c) optionally one or more dielectrically neutral compounds selected from the group of formulae IV and V:

[0037] [ka]

[0038] During the ceremony, R 41 and R 42 are independently of each other R in formula I 1 has the meaning given above, preferably R 41 represents alkyl, and R 42 represents alkyl, cyclopropyl, cyclopentyl or alkoxy, or R 41 represents alkenyl, and R 42 represents alkyl, [ka] Z41 and Z 42 are independent of each other, and Z 41 when they occur twice, they also independently represent -CH2CH2-, -COO-, trans-CH=CH-, trans-CF=CF-, -CHO-, -CF2O-, -C≡C- or a single bond, preferably one or more of them represents a single bond; p represents 0, 1 or 2, preferably 0 or 1, and

[0039] R 51 and R 52 are independently of each other R in formula I 1 has the meanings given above, preferably 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 2 to 4 C atoms, alkenyl or alkenyloxy, preferably alkenyloxy, [ka] Preferably [ka] represents Z 51 ~Z 53 are each independently -CH-CH-, -CH-O-, -CH=CH-, -C≡C-, -(CO)-O- or a single bond, preferably -C≡C-, -CH-CH-, -CH-O- or a single bond, particularly preferably a single bond or -C≡C-, i and j each independently represent 0 or 1; (i+j) preferably represents 0, 1 or 2, more preferably 0 or 1; However, each ring, preferably the phenylene ring, may be substituted with one or two alkyl groups, preferably methyl and / or ethyl groups, preferably one methyl group.

[0040] d) Also optionally, either instead or in addition, preferably dielectrically positive compounds selected from the group of compounds of formulae XII and XIII, excluding compounds of formula I, preferably compounds having a dielectric anisotropy greater than 3, respectively, preferably one or more compounds of formula XII.

[0041] [ka]

[0042] During the ceremony, R 2 represents an alkyl group having 1 to 15 C atoms (wherein one or more CH groups contain a terminal C atom, and in this group, independently of one another, O or S atoms are not directly linked to one another, and are substituted with -C≡C-, -CH=CH-, [ka] -O-, -S-, -(CO)-O-, -O-(CO)-, in addition, one or more H atoms may be replaced by F or Cl) or H, Preferably, alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl, fluorinated alkenyl having 2 to 7 C atoms, cycloalkyl, cycloalkylalkyl, cycloalkylalkoxy having 3 to 5 C atoms, most preferably alkyl, cyclopropyl, cyclopentyl or alkenyl; [ka] Preferably [ka] represents L 21 and L 22 represents H or F, L 23is H or CH3, preferably H, X 2 represents halogen, an alkyl halide having 1 to 3 C atoms or an alkenyl halide having 2 or 3 C atoms, preferably F, Cl or —CF3, very preferably F or —CF3, m represents 0, 1 or 2, preferably 1 or 2, particularly preferably 2,

[0043] R 3 represents an alkyl group having 1 to 15 C atoms (wherein one or more CH groups contain a terminal C atom, and in this group, independently of one another, O or S atoms are not directly linked to one another, and are substituted with -C≡C-, -CH=CH-, [ka] -O-, -S-, -(CO)-O-, -O-(CO)-, in addition, one or more H atoms may be replaced by F or Cl) or H, Preferably, alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl, fluorinated alkenyl having 2 to 7 C atoms, cycloalkyl, cycloalkylalkyl, cycloalkylalkoxy having 3 to 5 C atoms, most preferably alkyl, cyclopropyl, cyclopentyl or alkenyl; [ka] Preferably [ka] and L 31 and L 32 are each independently H or F, preferably L 31 represents F, L 33 is H or CH3, preferably H, X 3represents 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, Z 3 represents -CH2CH2-, -CF2CF2-, trans-CH=CH-, trans-CF=CF-, -CHO- or a single bond, preferably -CH2CH2-, trans-CH=CH- or a single bond, very preferably trans-CH=CH- or a single bond, n represents 0, 1, 2 or 3, preferably 1, 2 or 3, particularly preferably 1.

[0044] The liquid-crystalline media according to the present application preferably have a nematic phase.

[0045] Further objects of the invention are optical lenses or electro-optical devices and displays which use the liquid-crystalline media of the invention. Particularly useful are optical devices which contain one or more electro-optical lenses according to the invention and which have means for operating the lenses with dual-frequency addressing. The LC media according to the invention are used in electro-optical components with dual-frequency addressing.

[0046] Throughout this application, R 1 , R 2 , R 21 , R 22 , R 3 , R 31 , R 41 / 42 , R 51 / 52 For these definitions, alkyl means an alkyl group which may be linear or branched. Each of these groups is preferably linear and preferably has 1, 2, 3, 4, 5, 6, 7 or 8 C atoms and is therefore preferably methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl or n-heptyl.

[0047] When alkyl means a branched alkyl group, it preferably means 2-alkyl, 2-methylalkyl or 2-(2-ethyl)-alkyl, preferably 2-butyl (=1-methylpropyl), 2-methylbutyl, 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, in particular 2-methylbutyl, 2-methylbutoxy 4-methylhexyl, 2-hexyl, 2-octyl, 2-nonyl, 2-decyl and 2-dodecyl. The most preferred of these groups are 2-hexyl and 2-octyl.

[0048] Each branched group leading to a chiral compound is also referred to herein as a chiral group. Particularly preferred chiral groups are 2-alkyl, 2-alkoxy, 2-methylalkyl, 2-methylalkoxy, 2-fluoroalkyl, 2-fluoroalkoxy, 2-(2-ethyn)alkyl, 2-(2-ethyn)alkoxy, 1,1,1-trifluoro-2-alkyl, and 1,1,1-trifluoro-2-alkoxy.

[0049] Particularly preferred chiral groups are, for example, 2-butyl (= 1-methylpropyl), 2-methylbutyl, 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, in particular 2-methylbutyl, 2-methylbutoxy, 2-methylpentoxy, 3-methylpentoxy, 2-ethylhexoxy, 1-methylhexoxy, 2-octyloxy, 2-oxa-3-methylbutyl, 3-oxa-4-methylpentyl, 4-methylhexyl, 2-hexyl, 2-octyl, 2-nonyl, 2-decyl, 2-dodecyl, 6-methoxyoctoxy, 6-methyloctoxy, 6-methyloctanoyloxy, 5-methylheptyloxycarbonyl. 2-methylbutyryloxy, 3-methylvaleroyloxy, 4-methylhexanoyloxy, 2-chloropropionyloxy, 2-chloro-3-methylbutyryloxy, 2-chloro-4-methylvaleroyloxy, 2-chloro-3-methylvaleroyloxy, 2-methyl-3-oxapentyl, 2-methyl-3-oxahexyl, 1-methoxypropyl-2-oxy, 1-ethoxypropyl-2-oxy, 1-propoxypropyl-2-oxy, 1-butoxypropyl-2-oxy, 2-fluorooctyloxy, 2-fluorodecyloxy, 1,1,1-trifluoro-2-octyloxy, 1,1,1-trifluoro-2-octyl, and 2-fluoromethyloctyloxy. 2-Hexyl, 2-octyl, 2-octyloxy, 1,1,1-trifluoro-2-hexyl, 1,1,1-trifluoro-2-octyl and 1,1,1-trifluoro-2-octyloxy are highly preferred.

[0050] Throughout the application, in particular, alkenyl denotes an alkenyl group which may be linear or branched, preferably linear, and preferably has 2, 3, 4, 5, 6 or 7 or 8 C atoms. It is preferably vinyl, 1-E-alkenyl or 3-E-alkenyl, and it is most preferably vinyl, 1-E-propenyl, 1-E-butenyl, 1-E-pentenyl, 3-butenyl or 3-E-pentenyl.

[0051] C 3~5 -Cycloalkyl-(CH2) 0~1A group defined as: refers to a cyclopentyl, cyclobutyl or cyclopropyl group linked to the structure by a single bond or a CH group. Cyclopentyl is preferred.

[0052] The compounds of the general formulae I to XIII are prepared in a manner known per se under known and precise reaction conditions suitable for said reactions, as described in the literature (e.g., standard works such as Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart, etc.). Here, variants known per se, but not mentioned in more detail here, can be used.

[0053] In particular, compounds of formula I are known or are similar to known compounds and may be synthesized according to relevant prior art syntheses.

[0054] The invention furthermore relates to liquid-crystal displays, in particular IPS or FFS displays, particularly preferably FFS or SG-FFS displays, which contain a liquid-crystalline medium according to the invention.

[0055] The present invention further relates to a liquid crystal display of the IPS or FFS type comprising a 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 liquid crystal medium layer arranged between the substrates and comprising a polymerized component and a low molecular weight component, wherein the polymerized component is obtainable by polymerizing one or more polymerizable compounds in the liquid crystal medium between the substrates of the liquid crystal cell, preferably 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.

[0056] The displays according to the invention are preferably addressed by an active matrix (active matrix LCD, abbreviated as AMD), preferably by a matrix of thin-film transistors (TFT), but the liquid crystals according to the invention can also be used to advantage in displays with other known addressing methods.

[0057] The present invention further relates to a process for preparing a liquid-crystalline medium according to the invention by mixing one or more compounds of formula I or any of its sub-formulas with one or more low molecular weight liquid-crystalline compounds selected from formulae II, III and VI to IX and optionally additional mesogenic compounds and additives.

[0058] Above and below, the following meanings apply:

[0059] Unless otherwise indicated, the term "FFS" is used to refer to FFS and SG-FFS displays.

[0060] For the purposes of the present invention, the term "liquid crystal medium" is intended to denote a medium comprising a liquid crystal mixture and one or more polymerizable compounds (such as, for example, reactive mesogens). The term "liquid crystal mixture" (or "host mixture") is intended to denote a liquid crystal mixture consisting exclusively of non-polymerizable low molecular weight compounds, preferably two or more liquid crystal compounds, and optionally further additives, such as, for example, chiral dopants or stabilizers.

[0061] Particular preference is given to liquid-crystalline mixtures or liquid-crystalline media which have a nematic phase, especially at room temperature.

[0062] The term lens refers to classical optical lenses, structured lenses or other beam steering elements such as prisms. Electro-optical lenses refer to electrically switchable optical lenses. Switchable lenses may be suitable for making optical signals perceptible to an observer, e.g., the human eye.

[0063] In a preferred embodiment of the invention the liquid crystal medium comprises one or more compounds selected from IA, preferably having a dielectric anisotropy of >5.

[0064] [ka]

[0065] wherein the variables are defined as in Formula I above, and L 14 , L 15 are independently H or F, preferably L 14 is F, preferably L 15 is H.

[0066] More preferably, it is selected from the group of compounds of the following formula:

[0067] [ka]

[0068] [ka]

[0069] [ka]

[0070] [ka]

[0071] [ka]

[0072] [ka]

[0073] wherein the variables are defined above and below as in Formula I; L 4 is F or H, preferably H, L 5 is H, CH or CH, preferably H, and L 6 is F or H.

[0074] In formulas I, IA and I-1 to I-42, independently X 1 is F, CN or SCN, preferably CN or SCN, more preferably CN; L 12 is F, L 13 is H, L 14 is F, R 1 represents an alkyl group having 1 to 7 C atoms (wherein one or more CH groups contain a terminal C atom, and in this group, independently of one another, O atoms are not directly linked to one another, and may be -C≡C-, -CH=CH-, [ka] or -O-, provided that in addition one or more H atoms may be replaced by F.), preferably an alkyl group having 2 to 7 C atoms.

[0075] In a further preferred embodiment of the invention, the medium according to the invention comprises one or more compounds of formula II, preferably selected from the group of sub-formulae II-1 and II-2 thereof.

[0076] [ka]

[0077] where the parameters have the respective meanings given in Formula II above, and R 21 is preferably n-alkyl, and R 22 is preferably alkoxy.

[0078] In a further preferred embodiment of the invention, the medium according to the invention comprises one compound of formula III, preferably selected from the group of compounds of formulae III-1 and III-2

[0079] [ka]

[0080] In the formula, R 31 and R 32 has the meaning given in formula III.

[0081] Compounds of formula III-1 are particularly preferred. More preferably, the mixture comprises two or more, most preferably three or more compounds of formula III, especially formula III-1, most preferably formula III-1-1.

[0082] More preferred compounds of formula III are selected from the group consisting of the following subformulae:

[0083] [ka]

[0084] [ka]

[0085] In the formula, the individual radicals have, independently of one another, the following meanings: alkyl is a linear alkyl group having 1 to 6 carbon atoms or a branched or cyclic alkyl group having 3 to 12, preferably 3 to 6, carbon atoms; alkoxy is a linear alkoxy group having 1 to 6 C atoms or a branched or cyclic alkoxy group having 3 to 12, preferably 3 to 6, C atoms; alkenyl is a linear alkenyl group having 2 to 6 carbon atoms or a branched or cyclic alkenyl group having 3 to 12, preferably 3 to 6, carbon atoms; alkyl * is a linear alkyl group having 1 to 6 C atoms or a branched or cyclic alkyl group having 3 to 12, preferably 3 to 6, C atoms, alkoxy * is a linear alkoxy group having 1 to 6 C atoms or a branched or cyclic alkoxy group having 3 to 12, preferably 3 to 6, C atoms. Among these, formulae III-1-1 and III-2-2 are particularly preferred.

[0086] The liquid-crystalline medium preferably comprises one or more compounds selected from the group of formulae XIII-1j, XIII-1k and XIII-1m, which compounds are preferably selected from the group of compounds of formulae XIII-1j-1, XIII-1k-1, XIII-1m-1, preferably of formula XIII-1i-1.

[0087] [ka]

[0088] where the parameters have the meanings given above and X 3 preferably represents F or —OCF3.

[0089] The liquid-crystalline medium preferably comprises one or more compounds of the formula XIII-1k, which compounds are preferably selected from the group of the compounds of the formulae XIII-1m-1 and XIII-1m-2, preferably of the formula XIII-1m-1.

[0090] [ka]

[0091] where the parameters have the meanings given above, However, each ring, preferably the phenylene ring, may be substituted with one or two alkyl groups, preferably methyl and / or ethyl groups, preferably one methyl group.

[0092] The liquid-crystalline media according to the invention preferably comprise one or more dielectrically neutral compounds preferably selected from the group of the compounds of the formulae VI, VII, VIII and IX and having a dielectric anisotropy in the range from -1.5 to 3.

[0093] In this application, all elements include their respective isotopes. In particular, one or more H in a compound may be replaced by D, which is also particularly preferred in some embodiments. Correspondingly highly deuterated compounds allow, for example, the detection and recognition of said compounds.

[0094] In this application, Alkyl is particularly preferably straight-chain alkyl, in particular CH3-, C2H5-, n-C3H7-, n-C4H9- or n-C5H 11 - represents Alkenyl particularly preferably denotes CH2=CH-, E-CH3-CH=CH-, CH2=CH-CH2-CH2-, E-CH3-CH=CH-CH2-CH2- or E-(n-C3H7)-CH=CH-.

[0095] In a preferred embodiment of the invention, the medium according to the invention comprises one or more compounds of the formula VI, in each case selected from the group of compounds of the formulae VI-1 to VI-5, preferably one or more compounds of the formula VI-4 or VI-5.

[0096] [ka]

[0097] wherein the parameters have the respective meanings given above in formula VI, preferably In formula VI-1, R 61 and R62 each independently of the other denotes methoxy, ethoxy, propoxy, butoxy or pentoxy, preferably ethoxy, butoxy or pentoxy, more preferably ethoxy or butoxy, most preferably butoxy, In formulas IV-2 to IV-5, R 61 preferably denotes n-propyl, n-pentyl, vinyl, 1-E-propenyl, but-4-en-1-yl, pent-1-en-1-yl or pent-3-en-1-yl, and R 62 is an unsubstituted alkoxy group having 1 to 6 C atoms or an unsubstituted alkyl group having 1 to 7 C atoms, Preferably it is alkoxy with 2 or 4 C atoms, most preferably ethoxy with 2 or 4 C atoms, most preferably ethoxy with 2 to 5 C atoms, or preferably alkyl with 2 to 4 C atoms.

[0098] In a preferred embodiment of the invention, the medium according to the invention comprises one or more compounds of the formula VII in each case selected from the group of compounds of the formulae VII-1 to VII-3, preferably one or more compounds of the formula VII-1 and one or more compounds of the formula VII-2, respectively.

[0099] [ka]

[0100] wherein the parameters have the respective meanings given above in formula VII, preferably R 71 preferably represents n-propyl, n-pentyl, vinyl, 1-E-propenyl, but-4-en-1-yl, pent-1-en-1-yl or pent-3-en-1-yl, R 72represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms, or an unsubstituted alkoxy group, preferably having 1 to 6 C atoms, particularly preferably having 2 or 4 C atoms, most preferably an ethoxy group, However, each ring, preferably the phenylene ring, may be substituted with one or two alkyl groups, preferably methyl and / or ethyl groups, preferably one methyl group.

[0101] In a preferred embodiment of the invention, the medium according to the invention comprises one or more compounds of the formula VI-1, which are in each case selected from the group of compounds of the following formulae:

[0102] [ka]

[0103] In a preferred embodiment of the invention, the medium according to the invention comprises one or more compounds of the formula VI-2, which are in each case selected from the group of compounds of the following formulae:

[0104] [ka]

[0105] In a preferred embodiment of the invention, the medium according to the invention comprises one or more compounds of the formula VII-1, which are in each case selected from the group of compounds of the following formulae:

[0106] [ka]

[0107] In a preferred embodiment of the invention, the medium according to the invention comprises one or more compounds of the formula VII-2, which are in each case selected from the group of compounds of the following formulae:

[0108] [ka]

[0109] In addition to the compounds of formula I or its preferred sub-formulas, the medium according to the invention may contain one or more dielectrically negative compounds selected from the group of compounds of formulae VI and VII, preferably in a total concentration ranging from 5% to 90%, preferably from 10% to 80%, particularly preferably from 20% to 70%.

[0110] In a preferred embodiment of the invention, the medium according to the invention comprises one or more compounds of the formula VIII selected in each case from the group of compounds of the formulae VIII-1 to VIII-3, preferably one or more compounds of the formula VIII-1 respectively and / or one or more compounds of the formula VIII-3.

[0111] [ka]

[0112] wherein the parameters have the respective meanings given above in formula VIII, preferably R 81 preferably represents n-propyl, n-pentyl, vinyl, 1-E-propenyl, but-4-en-1-yl, pent-1-en-1-yl or pent-3-en-1-yl, R 82 represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably 1 to 5 C atoms, or an unsubstituted alkoxy group having 1 to 6 C atoms.

[0113] In formulas VIII-1 and VIII-2, R 82 preferably denotes alkoxy having 2 or 4 C atoms, most preferably ethoxy, and in formula VIII-3 preferably denotes alkyl, preferably methyl, ethyl or n-propyl, most preferably methyl.

[0114] In a further preferred embodiment the medium comprises one or more compounds of formula IV, preferably of formula IVa.

[0115] [ka] During the ceremony, R 41 represents an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkenyl group having 2 to 7 C atoms, preferably an n-alkyl group, particularly preferably a group having 2, 3, 4 or 5 C atoms, R 42 represents an unsubstituted alkyl group having 1 to 7 C atoms, an unsubstituted alkenyl group having 2 to 7 C atoms, or an unsubstituted alkoxy group having 1 to 6 C atoms, both of which preferably have 2 to 5 C atoms, and the unsubstituted alkenyl group preferably has 2, 3 or 4 C atoms, more preferably a vinyl group or a 1-propenyl group, in particular a vinyl group.

[0116] In a particularly preferred embodiment, the medium comprises one or more compounds of formula IV selected from the group of compounds of formulae IV-1 to IV-4, preferably formula IV-1.

[0117] [ka]

[0118] During the ceremony, alkyl and alkyl' independently denote alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms, alkenyl and alkenyl' independently denote alkenyl having 2 to 5 C atoms, preferably having 2 to 4 C atoms, particularly preferably having 2 C atoms, alkenyl' preferably denotes alkenyl having 2 to 5 C atoms, preferably having 2 to 4 C atoms, particularly preferably having 2 to 3 C atoms, Alkoxy represents alkoxy having 1 to 5 C atoms, preferably having 2 to 4 C atoms.

[0119] In a particularly preferred embodiment, the medium according to the invention comprises one or more compounds of formula IV-1 and / or one or more compounds of formula IV-2.

[0120] In a further preferred embodiment, the medium comprises one or more compounds of formula IV selected from the group of compounds of formula IV-2 and IV-3:

[0121] [ka]

[0122] During the ceremony, alkyl and alkyl' independently denote alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms, Alkoxy represents alkoxy having 1 to 5 C atoms, preferably having 2 to 4 C atoms.

[0123] In a further preferred embodiment, the medium comprises one or more compounds of formula V, preferably selected from the group of one or more compounds of formulae V-1 to V-7, preferably of formula V-4, V-6 or V-7.

[0124] [ka]

[0125] wherein the parameters have the meanings given above in Formula V, and q is 0 or 1, preferably 0; R 51 represents alkyl having 1 to 7 C atoms or alkenyl having 2 to 7 C atoms, and R 52represents alkyl having 1 to 7 C atoms, alkenyl having 2 to 7 C atoms or alkoxy having 1 to 6 C atoms, preferably alkyl or alkenyl.

[0126] In a further preferred embodiment, the medium comprises one or more compounds of formula V-1 selected from the following formulae:

[0127] [ka]

[0128] wherein "alkyl" has the definition given above and is preferably methyl, ethyl, propyl or butyl. Compounds of formula V-1a are particularly preferred.

[0129] In a further preferred embodiment the medium is 51 and R 52 wherein at least one of is alkenyl having 2 to 6 carbon atoms, preferably selected from the following formulae:

[0130] [ka]

[0131] wherein "Alkyl" has the definition given above and is preferably methyl or ethyl. Compounds of formula V-3d are particularly preferred.

[0132] In a further preferred embodiment, the medium comprises one or more compounds of formula V-5 selected from the group of compounds of formulae V-5a to V-5c:

[0133] [ka]

[0134] During the ceremony, Alkyl and alkyl *are each independently a straight-chain alkyl group having 1 to 6 carbon atoms, particularly methyl, ethyl, n-propyl and pentyl.

[0135] The liquid crystal medium preferably comprises two or more compounds selected from the group of the compounds of the formulae V-4a, V-4b and V-4c.

[0136] In a further preferred embodiment, the medium comprises one or more compounds of formula V-6 selected from the group of compounds of formulae V-6a to V-6c, preferably V-6a:

[0137] [ka]

[0138] During the ceremony, Alkyl and alkyl * are each independently a linear alkyl group having 1 to 6 carbon atoms, in particular methyl, ethyl or n-propyl, and Alkenyl preferably denotes alkenyl having 2 to 5 C atoms, preferably having 2 to 4 C atoms, particularly preferably vinyl.

[0139] In a further preferred embodiment, the medium comprises one or more compounds selected from compounds of formulae V-7 and V-8, more preferably selected from the following formulae:

[0140] [ka]

[0141] wherein "alkyl" has the definition given above and is preferably methyl, ethyl, propyl or butyl. Compounds of formula V-7a are particularly preferred.

[0142] The medium according to the invention preferably comprises the following compounds in the total concentrations indicated below: 5 to 50% by weight of one or more compounds selected from the group of compounds of formula I, and 0 to 40% by weight of one or more compounds of formula II, preferably selected from the group of compounds of formulae XII-1 and XII-2, and / or 1 to 50% by weight of one or more compounds of formula III, and / or 0 to 10% by weight of one or more compounds of formula VI, and / or 0 to 40% by weight of one or more compounds of formula VII, and / or 0 to 20% by weight of one or more compounds of formula VIII, and / or 0 to 20% by weight of one or more compounds of formula IX, and / or However, the total content of all compounds of formulae I, II, III and VI to IX present in the medium is preferably 95% or more, more preferably 97% or more, and most preferably 100%.

[0143] The latter condition applies to all media according to the present application.

[0144] In a particularly preferred embodiment, the medium according to the invention comprises: one or more compounds of formula I at a total concentration in the range of 5% to 40%, preferably 10% to 35%, and one or more compounds of formula II at a total concentration in the range of 0% to 30%, preferably 10% to 30%, and one or more compounds of formula III at a total concentration in the range of 0% to 30%, preferably 4% to 30%, and one or more compounds of formula VI in a total concentration ranging from 0% to 15% inclusive, preferably from 0% to 5% inclusive, and / or one or more compounds of formula VII in a total concentration ranging from 0% to 25% inclusive, preferably from 0% to 10% inclusive, and / or one or more compounds of formula VIII in a total concentration ranging from 0% to 30%; and / or One or more compounds of formula IX are contained in a total concentration in the range of 0% to 35% inclusive, preferably in the range of 1% to 20% inclusive.

[0145] The present invention also relates to electro-optical displays or electro-optical components containing a liquid-crystalline medium according to the invention, based on the FFS, IPS, VA or ECB effect, preferably based on the IPS or FFS effect, in particular those addressed by active matrix addressing devices.

[0146] The invention therefore likewise relates to the use of the liquid-crystalline media according to the invention in electro-optical displays or electro-optical components and to a process for preparing the liquid-crystalline media according to the invention, which is characterized in that one or more compounds of formula I are mixed with one or more further mesogenic compounds and optionally one or more additives.

[0147] In addition to the compounds of formulae I, II, III, VI, VII, VIII and IX, other 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 total mixture.

[0148] The liquid crystal media according to the invention may comprise one or more chiral compounds.

[0149] Particularly preferred embodiments of the present invention satisfy one or more of the following conditions: However, acronyms (abbreviations) are explained in Tables A-C and illustrated by examples in Table D.

[0150] Preferably, the medium according to the invention meets one or more of the following conditions:

[0151] i. The liquid-crystalline medium has a birefringence of 0.2 or more, particularly preferably 0.22 or more.

[0152] ii. The liquid-crystalline medium has a birefringence of less than or equal to 0.28, particularly preferably less than or equal to 0.25.

[0153] iii. The liquid crystal medium has a birefringence in the range of 0.21 or more and 0.25 or less.

[0154] iv. The liquid-crystalline medium preferably comprises one or more compounds of the (sub) formulae IA or I-1 and particularly preferred compounds of formula I selected from:

[0155] v. The liquid crystal medium comprises one or more particularly preferred compounds of formula III, preferably of formula III-1.

[0156] vi. The total concentration of compounds of formulae I, III and V-7 in the mixture as a whole is 30% or more, preferably 35% or more, preferably 60% or less, particularly preferably 55% or less, and very particularly preferably in the range of 25% or more to 45% or less.

[0157] vii. The liquid-crystalline medium comprises one or more compounds of formula V, preferably selected from formulae V-1, V-4 and V-5, preferably in a total concentration of 3% or more, in particular 5% or more, very particularly preferably 8% or more.

[0158] viii. The liquid crystal medium preferably contains one or more stabilizer compounds having a benzotriazole ring of any of the following structures: [ka] It is preferably contained in a total concentration in the range of ≧0% to ≦1%, preferably up to 0.8%, very particularly preferably in the range of ≧0.4% to ≦0.8%.

[0159] ix. The liquid crystal medium preferably contains a phenol type stabilizing additive selected from the following structures: (wherein n is 1 to 12, preferably 3): [ka] Preferably, it is contained in a total concentration of 0.01% or more, particularly 0.03% or more.

[0160] The invention further relates to an electro-optical display with active matrix addressing, characterized in that it contains a liquid-crystalline medium according to the invention as dielectric.

[0161] The liquid crystal mixture preferably has a nematic phase range with a temperature range of at least 70°C.

[0162] The rotational viscosity γ1 is preferably 350 mPa·sec or less, more preferably 250 mPa·sec or less, in particular 150 mPa·sec or less.

[0163] The mixtures according to the invention are suitable for all IPS and FFS-TFT applications which use dielectrically positive liquid crystal media, such as for example XB-FFS.

[0164] The liquid-crystalline media according to the invention preferably consist essentially entirely of 4 to 15, in particular 5 to 12, particularly preferably not more than 10 compounds, which are preferably selected from the group of the compounds of the formulae I, II, III, VI, VII, VIII and IX.

[0165] The liquid crystal media according to the invention may also contain more than 18 compounds, in which case the media preferably contain from 18 to 25 compounds.

[0166] In a preferred embodiment, the liquid crystal media according to the invention predominantly comprise, preferably consist essentially of and most preferably consist substantially completely of compounds which do not contain cyano groups.

[0167] In a preferred embodiment, the liquid-crystalline media according to the invention comprise compounds selected from the group of compounds of the formulae I, II, III, VI, VII, VIII and IX, preferably consisting predominantly, particularly preferably consisting essentially and very particularly preferably consisting substantially completely of compounds of said formulae.

[0168] The liquid-crystalline media according to the invention preferably have a nematic phase in each case at least from -10°C to 70°C, particularly preferably from -20°C to 80°C, very particularly preferably from -30°C to 85°C, and most preferably from -40°C to 90°C.

[0169] In this document, the expression "having a nematic phase" means, on the one hand, that no smectic phase or crystallization is observed at low temperatures at the corresponding temperatures, and, on the other hand, that heating from the nematic phase does not result in clearing. Low-temperature studies are carried out in a flow viscometer at the corresponding temperatures and are confirmed by storage for at least 100 hours in test cells with a layer thickness corresponding to the electro-optical application. A medium is considered stable at this temperature if its storage stability at a temperature of -20°C in the corresponding test cell is 1,000 hours or more. At temperatures of -30°C and -40°C, the corresponding times are 500 hours and 250 hours, respectively. At higher temperatures, the clearing point is measured conventionally in capillary tubes.

[0170] In a preferred embodiment, the liquid-crystalline media according to the invention are characterized by values of optical anisotropy in the medium to high range, which make them highly suitable, for example, for optical lenses made from the liquid-crystalline material. The birefringence values are preferably in the range from ≧0.2 to ≦0.35, particularly preferably in the range from ≧0.2 to ≦0.32, very particularly preferably in the range from ≧0.22 to ≦0.30.

[0171] In a preferred embodiment, the liquid-crystalline media according to the invention are characterized by values of the optical anisotropy in the medium range, which makes them, for example, very suitable for LC displays. The birefringence values are preferably in the range from ≧0.09 to ≦0.22, particularly preferably in the range from ≧0.10 to ≦0.20, very particularly preferably in the range from ≧0.12 to ≦0.18.

[0172] In this embodiment, the liquid crystal medium according to the present invention usually has a positive dielectric anisotropy Δε in the range of 1.5 to 15, preferably 2.5 or more and 12 or less, more preferably 8 or less, particularly preferably 3 or more and 8 or less.

[0173] The liquid crystal medium according to the present invention preferably has a relatively low threshold voltage (V0) in the range of 1.0 V to 5.0 V, preferably 2.5 V or less, preferably 1.2 V to 2.2 V, particularly preferably 1.3 V to 2.0 V.

[0174] In addition, the liquid-crystalline media according to the invention have high values of VHR in a liquid-crystal cell.

[0175] Here, in general, liquid-crystalline media with low addressing voltages or threshold voltages have a lower VHR than liquid-crystalline media with higher addressing voltages or threshold voltages, and vice versa.

[0176] These preferred values of the individual physical properties are also preferably in each case maintained in combination with one another by the media according to the invention.

[0177] In this application, the term "compound" is also referred to as "compound(s)" and refers to both a compound and multiple compounds, unless otherwise specified.

[0178] For purposes of the present invention, unless otherwise indicated in particular cases, the following definitions apply in connection with the identification of the components of the compositions.

[0179] "Contains": The concentration of the component in question in the composition is preferably 5% or more, particularly preferably 10% or more, very particularly preferably 20% or more.

[0180] "Consists predominantly of": The concentration of the component of interest in the composition is preferably 50% or more, particularly preferably 55% or more, very particularly preferably 60% or more.

[0181] "Consists essentially of": The concentration of the component in question in the composition is preferably 80% or more, particularly preferably 90% or more, very particularly preferably 95% or more.

[0182] "Consists essentially completely of": The concentration of the component of interest in the composition is preferably 98% or more, particularly preferably 99% or more, very particularly preferably 100.0%.

[0183] This applies both to the medium as a composition having components which may be groups of compounds and individual compounds of the composition, and also to groups of compounds having their respective components and compounds. As far as the concentration of individual compounds relative to the medium as a whole is concerned, the term "comprising" means that the concentration of the compound(s) or compounds in question is preferably 1% or more, particularly preferably 2% or more, very particularly preferably 4% or more.

[0184] In the present invention, "≦" means less than or equal to, preferably less than, and "≧" means greater than or equal to, preferably greater than.

[0185] In the present invention, [ka] represents trans-1,4-cyclohexylene, [ka] represents a mixture of both cis- and trans-1,4-cyclohexylene, [ka] represents 1,4-phenylene.

[0186] Throughout this application, 1,3-cyclopentenylene is a moiety selected from the group of formulae below. [ka] Preferably [ka] Most preferably [ka]

[0187] In the present invention, the expression "dielectrically positive compound" means a compound with Δε > 1.5, the expression "dielectrically neutral compound" means a compound with -1.5 ≦ Δε ≦ 1.5, and the expression "dielectrically negative compound" means a compound with Δε < -1.5. The dielectric anisotropy of a compound is determined herein by dissolving 10% of the compound in a liquid crystal host and determining the capacitance of the resulting mixture at 1 kHz in at least one test cell with a cell thickness of 20 μm, in each case with homeotropic and homogeneous surface alignment. The measurement voltage is typically between 0.5 V and 1.0 V, but always below the capacitance threshold of the respective liquid crystal mixture under consideration.

[0188] The host mixture used for the dielectrically positive and dielectrically neutral compounds is ZLI-4792, and the host mixture used for the dielectrically negative compounds is ZLI-2857, both manufactured by Merck, Germany. The value for each compound studied is obtained from the change in the dielectric constant of the host mixture after adding the compound studied and is extrapolated to 100% for the compound used. The compound studied is dissolved in the host mixture in an amount of 10%. If the solubility of the substance is too low for this purpose, the concentration is reduced stepwise by half until the study can be carried out at the desired temperature.

[0189] The liquid-crystalline medium according to the present invention may also contain, if necessary, conventional amounts of further additives, such as stabilizers and / or pleochroic, e.g., dichroic dyes and / or chiral dopants. The total amount of these additives used is preferably from 0% to 10%, particularly preferably from 0.1% to 6%, based on the total amount of the mixture. The concentration of each compound used is preferably from 0.1% to 3%. The concentrations of these and similar additives are generally not taken into account when specifying the concentration and concentration range of the liquid-crystalline compound in the liquid-crystalline medium.

[0190] In a preferred embodiment, the liquid-crystalline medium according to the present invention comprises a polymer precursor, which in turn comprises one or more reactive compounds, preferably reactive mesogens, and optionally further additives, such as polymerization initiators and / or polymerization retarders, in the usual amounts. The total amount of these additives used is preferably from 0% to 10%, particularly preferably from 0.1% to 2%, based on the total amount of the mixture. The concentrations of these and similar additives are generally not taken into account when specifying the concentration and concentration range of the liquid-crystalline compounds in the liquid-crystalline medium.

[0191] The composition comprises a number of compounds, preferably from 3 to 30, particularly preferably from 6 to 20, and very particularly preferably from 10 to 16, which are mixed in a conventional manner. Generally, the desired amount of the compound used in the smaller amount is dissolved in the compound that constitutes the main component of the mixture. This is advantageously carried out at elevated temperature. Observing the completion of the dissolution operation is particularly easy if the selected temperature is above the clearing point of the main component. However, it is also possible to prepare liquid crystal mixtures in other conventional ways, for example, using premixes or in so-called "multi-bottle systems."

[0192] The mixtures according to the invention exhibit a very wide nematic phase range with a clearing point above 65° C., very favorable values of the capacity threshold and relatively high values of retention, and at the same time very good low-temperature stability at −30° C. and −40° C. Furthermore, the mixtures according to the invention are distinguished by a low rotational viscosity γ1.

[0193] It goes without saying for those skilled in the art that media according to the invention for use in VA, IPS, FFS or PALC displays may also comprise compounds in which, for example, H, N, O, Cl or F is replaced by the corresponding isotopes.

[0194] The structure of the liquid crystal display according to the invention corresponds to a conventional configuration, for example as described in US Patent Application Publication No. 2002 / 0041354.

[0195] The liquid crystal phase according to the invention can be modified by suitable additives to be used in any type of display disclosed to date, for example IPS and FFS LCD displays.

[0196] Table E below shows possible dopants that may be added to the mixture according to the invention. When the mixture contains one or more dopants, the dopant(s) are employed in an amount of 0.01% to 4%, preferably 0.1% to 1.0%.

[0197] For example, stabilizers that may be added to the mixtures according to the invention are shown below in Table F, preferably in amounts of 0.01% to 6%, in particular 0.1% to 3%.

[0198] For the purposes of the present invention, all concentrations are given in % by weight unless expressly stated otherwise and relate to the corresponding mixture as a whole or to the entire mixture components unless expressly stated otherwise. In this context, the term "mixture" denotes a liquid-crystalline medium.

[0199] Unless expressly indicated otherwise, all temperature values given herein, such as, for example, melting points T(C,N), smectic (S) to nematic (N) phase transitions T(S,N) and clearing points T(N,I), are given in degrees Celsius (°C), and all temperature differences are given in degrees difference (° or degrees), respectively.

[0200] In this specification, the birefringence Δn is defined by the following formula.

[0201]

number

[0202] In the formula, n e is the extraordinary refractive index, and n o is the ordinary refractive index. The extraordinary refractive index n e and ordinary refractive index n o can be measured using an Abbe refractometer.

[0203] Δε is (ε ∥ -ε ⊥ ) The dielectric constant of a compound is determined from the change in the respective value of the host medium upon addition of the compound of interest. Values are extrapolated to 100% concentration of the compound of interest. Exemplary host media are ZLI-4792 or ZLI-2857, both of which are commercially available from Merck (Darmstadt).

[0204] Unless expressly indicated otherwise in the present invention, the term "threshold voltage" relates to the capacitive threshold (V0), also known as the Freederickss threshold.

[0205] Unless otherwise expressly indicated in each case, all physical properties are determined according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals", November 1997, Merck KGaA, Germany, applying a temperature of 20°C, Δn is determined at 436 nm, 589 nm and 633 nm, and Δε is determined at 1 kHz.

[0206] The electro-optical properties, such as the threshold voltage (V) (capacitive measurement), as well as the switching behavior, were determined in a test cell manufactured by Merck Japan. The test cell had a soda-lime glass substrate and a polyimide alignment layer (SE-1211 and diluent). ** The liquid crystals were constructed in an ECB or VA configuration with 26 (mixed in a 1:1 ratio, both manufactured by Nissan Chemical Industries, Ltd., Japan), and the alignment layers were rubbed perpendicular to each other, resulting in a homeotropic alignment of the liquid crystals. The surface area of the transmission was 1 cm, with a substantially square ITO electrode. 2 is.

[0207] Unless otherwise stated, no chiral dopants are added to the liquid crystal mixtures used, but the liquid crystal mixtures used according to the invention are also suitable for applications where this type of doping is required.

[0208] The rotational viscosity is determined using a rotating permanent magnet method, and the flow viscosity is determined in a modified Ubbelohde viscometer. The liquid crystal mixtures ZLI-2293, ZLI-4792, and MLC-6608 are all products of Merck KGaA, Germany. The rotational viscosity values determined at 20°C are 161 mPa·s, 133 mPa·s, and 186 mPa·s, respectively, and the flow viscosity (ν) is 21 mm 2 ·s -1 , 14mm 2 ·s -1 and 27mm 2 ·s -1 is.

[0209] For practical purposes, the refractive index dispersion of a material is conventionally characterized as follows, and this will be used throughout this invention unless otherwise stated. Birefringence values are determined at a temperature of 20°C and several fixed wavelengths using a modified Abbe refractometer with a homeotropically aligned surface on the side of the prism that contacts the material. Birefringence values are determined at specific wavelengths of 436 nm (selected spectral lines of a low-pressure mercury lamp), 589 nm (sodium D-line), and 633 nm (helium-neon laser) using an attenuator / diffuser combination to prevent eye damage to the observer. In the table below, Δn is given at 589 nm, and Δ(Δn) is given by Δ(Δn) = Δn(436 nm) - Δn(633 nm).

[0210] Unless otherwise clearly indicated, the following symbols are used: V Capacitive threshold voltage at 20℃ [V] n e Anomalous refractive index measured at 20°C and 589nm Normal refractive index measured at 020°C and 589nm Δn Optical anisotropy measured at 20°C and 589 nm λ Wavelength λ[nm] Δn(λ) Optical anisotropy measured at 20°C and wavelength λ Δn(Δn) Δn(20℃, 436nm)-Δn(20℃, 633nm) The change in optical anisotropy defined as Δn(Δn * ) Δ(Δn) / Δn(20℃, 589nm) The "relative change in optical anisotropy" is defined as follows: ε ⊥ Permittivity perpendicular to the director at 20°C and 1kHz ε ∥ Dielectric constant parallel to the director at 20°C and 1kHz Δε Dielectric anisotropy at 20°C and 1kHz T(N,I) or cl.p. Clearing point [℃] ν Flow viscosity measured at 20℃ (mm 2 ·s -1 ) γRotational viscosity measured at 120℃ (mPa·s) Elastic constant for "splay" deformation at k120°C [pN] Elastic constant for "twist" deformation at k220℃ [pN]

number

number

[0211] The following examples illustrate the present invention without limiting it. However, the following examples will show those skilled in the art the preferred compounds to be used, their respective concentrations and their combinations with each other, as well as preferred mixing concepts. In addition, the examples illustrate the properties and property combinations that can be achieved.

[0212] In the present invention and the following examples, the structures of liquid crystal compounds are represented by acronyms, and are converted to chemical formulas 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 H2 n , C m H2 m and C l H 2lare linear alkyl or alkylene groups, each having n, m and l carbon atoms in each case. Preferably, n, m and l are each independently 1, 2, 3, 4, 5, 6 or 7. Table A shows the codes for the ring elements of the nucleus of the compounds, Table B lists the bridging units, and Table C lists the meaning of the symbols for the leftmost and rightmost groups of the molecule. The acronyms consist of the code for the ring element with an optional linking group, followed by the code for the first hyphen and the leftmost group, and the code for the second hyphen and the rightmost group. Table D shows exemplary structures of compounds with their respective abbreviations.

[0213] <Table A: Ring elements>

[0214] [Table 1]

[0215] [Table 2]

[0216] [Table 3]

[0217] <Table B: Crosslinking Units>

[0218] [Table 4]

[0219] <Table C: Terminal group>

[0220] [Table 5]

[0221] In the table, n and m are each integers, and the three dots "..." are places for other abbreviations from this table.

[0222] In addition to the compound of formula B, the mixture according to the invention preferably comprises one or more compounds as described below.

[0223] The following abbreviations are used: (n, m, k and l are each independently an integer, preferably 1 to 9, preferably 1 to 7; k and l may be 0, preferably 0 to 4, more preferably 0 or 2, most preferably 2; n is preferably 1, 2, 3, 4 or 5; in the combination "-nO-", it is preferably 1, 2, 3 or 4, more preferably 2 or 4; m is preferably 1, 2, 3, 4 or 5; in the combination "-Om", it is preferably 1, 2, 3 or 4, more preferably 2 or 4. The combination "-lVm" is preferably "2V1".)

[0224] Exemplary and Preferred Dielectrically Positive Compounds

[0225] [Table 6]

[0226] [Table 7]

[0227] [Table 8]

[0228] [Table 9]

[0229] [Table 10]

[0230] [Table 11]

[0231] [Table 12]

[0232] [Table 13]

[0233] [Table 14]

[0234] Exemplary and Preferred Dielectrically Neutral Compounds

[0235] [Table 15]

[0236] [Table 16]

[0237] [Table 17]

[0238] [Table 18]

[0239] [Table 19]

[0240] [Table 20]

[0241] [Table 21]

[0242] [Table 22]

[0243] [Table 23]

[0244] Exemplary and Preferred Dielectrically Negative Compounds

[0245] [Table 24]

[0246] [Table 25]

[0247] [Table 26]

[0248] [Table 27]

[0249] [Table 28]

[0250] [Table 29]

[0251] [Table 30]

[0252] [Table 31]

[0253] [Table 32]

[0254] [Table 33]

[0255] [Table 34]

[0256] Table E lists chiral dopants that are preferably used in the mixtures according to the invention.

[0257]

[0258] [Table 35]

[0259] [Table 36]

[0260] [Table 37]

[0261] In a preferred embodiment of the invention, the medium according to the invention comprises one or more compounds selected from the group of compounds of Table E.

[0262] Table F shows stabilizers that can be preferably additionally used in the mixtures according to the invention, where the parameter n represents an integer ranging from 1 to 12. In particular, the phenol derivatives shown below can be used as additional stabilizers, since they act as antioxidants.

[0263]

[0264] [Table 38]

[0265] [Table 39]

[0266] [Table 40]

[0267] [Table 41]

[0268] [Table 42]

[0269] [Table 43]

[0270] In a preferred embodiment of the invention, the medium according to the invention comprises one or more compounds selected from the group of compounds from Table F, in particular one or more compounds selected from the group of compounds of the following two formulae:

[0271] [Table 44] [Example]

[0272] The following examples illustrate the present invention without limiting it in any way. However, the physical properties clarify for those skilled in the art the achievable properties and the extent to which they can be modified. Thus, in particular, the various property combinations that can be preferably achieved are well defined for those skilled in the art.

[0273] <Mixture example> Exemplary mixtures are disclosed below. All percentages are by weight.

[0274] The following mixtures are prepared and considered:

[0275] <Mixture example 1>

[0276] [Table 45]

[0277] The crossover frequency of this mixture is f CO is 4.0kHz.

[0278] <Mixture example 1.1> 0.03% of the compound of the formula [ka] is added to the mixture M-1. The resulting mixture M-1.1 is characterized by improved stability to harsh conditions, especially exposure to light.

[0279] <Mixture example 1.2> 0.4% of the compound of the formula [ka] is added to the mixture M-1. The resulting mixture M-1.2 is characterized by improved stability to harsh conditions, especially exposure to light.

[0280] <Mixture example 1.3> 0.05% of the compound of the formula [ka] is added to the mixture M-1. The resulting mixture M-1.3 is characterized by improved stability to harsh conditions, especially exposure to light.

[0281] Instead, for stabilization purposes, the following formula is used: 0.05% [ka] (wherein the two O atoms bonded to the N atom represent radicals) or [ka] One of the compounds may be added to mixture M-1.

[0282] <Comparative mixture example 1>

[0283] [Table 46]

[0284] The crossover frequency of this mixture is f CO is 12.5kHz.

[0285] <Mixture example 2>

[0286] [Table 47]

[0287] The crossover frequency of this mixture is f CO is 6.0kHz.

[0288] <Mixture example 3>

[0289] [Table 48]

[0290] The crossover frequency of this mixture is fCO is 10kHz.

[0291] <Mixture example 4>

[0292] [Table 49]

[0293] The crossover frequency of this mixture is f CO is 7.0kHz.

[0294] <Mixture example 5>

[0295] [Table 50]

[0296] The crossover frequency of this mixture is f CO is 6.0kHz.

[0297] <Mixture example 6>

[0298] [Table 51]

[0299] The crossover frequency of this mixture is f CO is 6.0kHz.

Claims

1. Liquid-crystalline medium having a nematic phase, characterized in that it comprises one or more compounds of the formula I and one or more additional compounds selected from the group of the formulae II, III and VI to IX. 【Chemical 1】 (In the formula, R １ is an alkyl group having 1 to 15 carbon atoms (but containing at least one CH ２ The group contains a terminal C atom, and in this group, independently of one another, O or S atoms are not directly linked to one another, and may be -C≡C-, -CH=CH-, 【Chemistry 2】 -O-, -S-, -(CO)-O-, -O-(CO)-, provided that in addition one or more H atoms may be replaced by F or Cl) or H, 【Chemistry 3】 Preferably 【Chemistry 4】 represents 【Chemistry 5】 Preferably 【Chemistry 6】 represents Z １ is —C≡C—, —(CO)O— or —CF ２ represents O-, Z ２ represents a single bond, —(CO)O—, or —CF ２ represents O-, L １１ , L １２ are independently H, F or Cl; L １３ is H, CH ３ or CH ２ CH ３ and X １ are -CN, -SCN, -OCF ３ or F, n represents 1 or 2. 【Chemistry 7】 (In the formula, R ２１ and R ２２ are each independently R １ and preferably alkyl or alkoxy having 1 to 7 C atoms, alkenyl, alkenyloxy or alkoxyalkyl having 2 to 7 C atoms or C ３～５ -cycloalkyl-(CH ２ ) ０～１ and 【Chemistry 8】 and n is independently 0 or 1; 【Chemistry 9】 represents L ３ is CH ３ , OCH ３ or CH ２ CH ３ and 【Chemistry 10】 Preferably 【Chemistry 11】 represents R ３１ and R ３２ are each independently R １ and preferably alkyl or alkoxy having 1 to 7 C atoms, alkenyl, alkenyloxy or alkoxyalkyl having 2 to 7 C atoms or C ３～５ -cycloalkyl-(CH ２ ) ０～１ -O-, most preferably alkoxy of 1 to 7 C atoms, cyclopentyl-O- or cyclopentyl-CH ２ -O-, R ６１ is R １ and preferably 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, an unsubstituted alkenyloxy group having 2 to 6 C atoms or a C ３～５ -cycloalkyl-(CH ２ ) ０～１ represents R ６２ is R １ is defined as follows: L ６１ , L ６２ are independently H or methyl; l represents 0 or 1; R ７１ is R １ is defined as follows: R ７２ is R １ is defined as follows: L ７１ , L ７２ are independently H or methyl, preferably H; 【Chemistry 12】 represents R ８１ is R １ is defined as follows: R ８２ is R １ is defined as follows: L ８１ , L ８２ are independently H or methyl; 【Chemistry 13】 represents Z ８ is -(CO)-O-, -CH ２ —O—, —CF ２ —O— or —CH ２ -CH ２ represents - and o represents 0 or 1; R ９１ and R ９２ are independently R ７２ has the meaning given above, R ９１ preferably denotes an alkyl group having 2 to 5 C atoms, preferably having 3 to 5 C atoms, R ９２ preferably 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, 【Chemistry 14】 represents, and p is 0 or 1.

2. 2. Liquid-crystalline medium according to claim 1, comprising one or more compounds of the formula III

3. 3. Liquid-crystalline medium according to claim 1, characterized in that it comprises one or more compounds of the formula II

4. 4. Liquid-crystalline medium according to claim 1, characterized in that it comprises one or more dielectrically neutral compounds selected from the group of the formulae IV and V 【Chemistry 15】 (In the formula, R ４１ and R ４２ are independently an alkyl group having 1 to 15 carbon atoms, provided that one or more CH ２ The group contains a terminal C atom, and in this group, independently of one another, O or S atoms are not directly linked to one another, and may be -C≡C-, -CH=CH-, 【Chemistry 16】 may be replaced by —O—, —S—, —(CO)—O—, or —O—(CO)—, provided that in addition one or more H atoms may be replaced by F or Cl; 【Chemistry 17】 Z ４１ and Z ４２ are Z independently of each other. ４１ appears twice, they also independently represent -CH ２ CH ２ -, -COO-, trans-CH=CH-, trans-CF=CF-, -CH ２ O-, -CF ２ represents O—, —C≡C— or a single bond; p represents 0, 1 or 2; R ５１ and R ５２ are each independently R ４１ and R ４２ has one of the meanings given to 【Chemistry 18】 Z ５１ ~Z ５３ are each independently —CH ２ -CH ２ -, -CH ２ represents —O—, —CH═CH—, —C≡C—, —COO— or a single bond, and i and j each independently represent 0 or 1; However, each ring, preferably the phenylene ring, may be substituted with one or two alkyl groups, preferably with methyl and / or ethyl groups, preferably with one methyl group.

5. 5. The liquid-crystalline medium according to claim 1, comprising one or more compounds selected from the group of the compounds of the formulae I-1 to I-42: 【Chemistry 19】 【Chemistry 20】 【Chemical 21】 【Chemical 22】 【Chemical 23】 【Chemistry 24】

6. Z １ is -C≡C-, and X １ is CN or SCN 6. Liquid-crystalline medium according to claim 1, comprising one or more compounds of the formula I

7. 7. Liquid-crystalline medium according to claim 1, which additionally comprises one or more compounds selected from the group of compounds of the formulae VII, VIII, IX and X

8. 8. Liquid-crystalline medium according to claim 1, characterized in that the total concentration of compounds of formula I in the medium as a whole is greater than or equal to 10% by weight and less than 35% by weight.

9. 9. Liquid-crystalline medium according to claim 1, comprising one or more compounds selected from the compounds of structures V-7 and V-8. 【Chemistry 25】 (In the formula, R ４１ and R ４２ are independently an alkyl group having 1 to 15 carbon atoms, provided that one or more CH ２ The group contains a terminal C atom, and in this group, independently of one another, O or S atoms are not directly linked to one another, and may be -C≡C-, -CH=CH-, 【Chemical 26】 may be replaced by —O—, —S—, —(CO)—O—, or —O—(CO)—, provided that in addition, one or more H atoms may be replaced by F or Cl.

10. Electro-optical lens or electro-optical display, characterized in that it contains a liquid-crystalline medium according to any one of claims 1 to 9.

11. 11. An optical device including one or more electro-optical lenses according to claim 10, characterized in that it has means for operating the lenses with dual frequency addressing.

12. Use of a medium according to any one of claims 1 to 9 in an electro-optical component with dual frequency addressing.

13. 10. Process for preparing a liquid-crystalline medium according to any one of claims 1 to 9, characterized in that one or more compounds of formula I are mixed with one or more compounds selected from compounds of formulae II, III and VI to IX and optionally one or more further mesogenic compounds and additives.

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