TW201840535A - Liquid-crystalline medium and liquid-crystal display comprising the same - Google Patents

Abstract

The present invention relates to a liquid-crystalline medium (LC medium) comprising a polymerizable piperidine derivative as an additive for stabilization, to the use thereof for electro-optical purposes, and to LC displays containing this medium, particularly to liquid-crystal displays which use the IPS (in-plane switching) or the FFS (fringe field switching) effect using dielectrically positive liquid crystals.

Description

Liquid crystal medium and liquid crystal display containing same

The present invention relates to a liquid crystal medium (LC medium) containing a polymerizable piperidine derivative as an additive for stabilization, to its use for electro-optical purposes, and to an LC display containing the medium, and more particularly to use using dielectrically positive liquid crystal plane switching (i n- p lane s witching, IPS) type liquid crystal or a fringe field switching (f ringe f ield s witching, FFS) displays the effect.

Liquid crystal is mainly used as a dielectric in display devices because the optical characteristics of these substances can be modified by applying a voltage. Those skilled in the art are extremely familiar with the liquid crystal electro-optical device based on it, and can be based on various effects. Examples of these devices are units with dynamic scattering, deformation of aligned phase (DAP) units, guest / main units, TN units with a "twisted nematic" structure, and "super-twisted nematic"(""super-twistednematic" (STN) unit, "superbirefringence effect" (SBE) unit and "optical mode interference" (OMI) unit. The most common display device is based on the Schadt-Helfrich effect and has a twisted nematic structure. In addition, there are also units that operate by an electric field parallel to the substrate and the liquid crystal plane, such as "in-plane switching"("IPS") cells. TN, STN, fringe field switching (FFS) and IPS units are particularly the areas of application for the media according to the present invention that are currently of commercial interest. Liquid crystal materials must have good chemical and thermal stability and good stability to electric fields and electromagnetic radiation. In addition, the liquid crystal material should have low viscosity and produce short addressing time, low threshold voltage, and high contrast in the cell. In addition, it should have a suitable mesophase, such as the nematic or cholesteric intermediate of the units mentioned above, at common operating temperatures, i.e. within the widest possible range above and below room temperature. phase. Since liquid crystals are usually used as a mixture of a plurality of components, it is important that the components are easily miscible with each other. Other characteristics such as conductivity, dielectric anisotropy, and optical anisotropy must meet various requirements depending on the type of unit and the field of application. For example, materials used for cells with a twisted nematic structure should have positive dielectric anisotropy and low electrical conductivity. For example, a matrix liquid crystal display with integrated non-linear elements for switching individual pixels (MLC displays) needs to have a large positive dielectric anisotropy, a wide nematic phase, a relatively low birefringence, and an extremely high Medium with specific resistance, good UV and temperature stability, and low vapor pressure. Such matrix liquid crystal displays are known. An example of a non-linear element that can be used to individually switch individual pixels is an active element (ie, a transistor). The term "active matrix" is then used, which distinguishes between two types: 1. Metal oxide semiconductor (MOS) or other diodes on a silicon wafer as a substrate. 2. A thin-film transistor (TFT) on the glass plate is used as the substrate. The use of monocrystalline silicon as the substrate material limits the size of the display, because even the module assemblies of various partial displays can cause problems at the joints. In the more promising type 2 (which is better), the electro-optic effect used is usually the TN effect. A distinction is made between two technologies: TFTs containing compound semiconductors such as CdSe, or TFTs based on polycrystalline or amorphous silicon. The latter technology is undergoing intensive research worldwide. A TFT matrix is applied to the inside of one glass plate of a display, while the other glass plate carries a transparent counter electrode on its inside. Compared with the size of the pixel electrode, the TFT is extremely small and has almost no adverse effect on the image. This technology can also be extended to a fully colour-capable display, in which mosaics of red, green and blue filters are arranged in such a way that the filter elements are opposed to each switchable pixel. TFT displays are commonly used as TN units with cross polarizers in transmission and are backlit. As used herein, the term MLC display covers any matrix display with integrated non-linear elements, that is, in addition to the active matrix, the display also has passive elements such as a rheostat or a diode (MIM = metal-insulator-metal). Such MLC displays are particularly suitable for TV applications such as pocket televisions or high-information displays suitable for computer applications (laptops) and for use in automotive or aircraft construction. In addition to the issues related to the angular dependence of the contrast and the response time, the specific resistance of the liquid crystal mixture is not high enough, which causes difficulties in MLC displays [TOGASHI, S., SEKIGUCHI, 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, page 141 and below, Paris; STROMER, M., Proc. Eurodisplay 84, September 1984: Design of Thin Film Transistors for Matrix Addressing of Television Liquid Crystal Displays, p. 145 and below, Paris]. As the resistance decreases, the contrast of the MLC display decreases and the problem of afterimage removal occurs. Because the specific resistance of a liquid crystal mixture typically decreases with the life of the MLC display due to interaction with the inner surface of the display, high (initial) resistance is extremely important in order to obtain an acceptable lifetime. Especially for low-volt mixtures, it has hitherto not been possible to achieve very high specific resistance values. In addition, it is important that the specific resistance exhibits the smallest possible increase as the temperature increases and after heating and / or UV exposure. The low temperature properties of prior art mixtures are also particularly disadvantageous. It is required that no crystalline and / or smectic phases appear even at low temperatures and that the temperature dependence of viscosity is as low as possible. Therefore, prior art MLC displays do not meet today's requirements. In addition to using a backlight, that is, a liquid crystal display that operates in a transmissive mode and a transflective mode as needed, reflective liquid crystal displays are also of particular interest. These reflective liquid crystal displays use ambient light for information displays. Therefore, it consumes significantly less energy than a backlit liquid crystal display with a corresponding size and resolution. Because the TN effect is characterized by excellent contrast, such reflective displays can be read well even in bright ambient conditions. This is known as, for example, a simple reflective TN display for watches and pocket calculators. However, this principle can also be applied to high-quality, higher-resolution active matrix addressing displays such as TFT displays. Here, as in a conventionally known transmissive TFT-TN display, it is necessary to use a liquid crystal having a low birefringence (Δn) in order to achieve a low light retardation (d · Dn). This low light block results in a generally lower contrast viewing angle dependence (see DE 30 22 818). In reflective displays, the use of liquid crystals with low birefringence is even more important than in transmissive displays, because in reflective displays, the effective layer thickness through which light passes is approximately the same as a transmissive display with the same layer thickness Twice. For TV and video applications, a display with fast response time is required to enable multimedia content such as movies and video games to be reproduced with near-realistic quality. In particular, if a liquid crystal medium having a low viscosity value, particularly a low rotational viscosity γ ₁ value and high optical anisotropy (Δn) is used, such short response times can be achieved. In order to achieve the 3D effect by means of shutter glasses, in particular a fast-switching mixture with a low rotational viscosity and a correspondingly high optical anisotropy (Δn) is used. With the aid of an electro-optic lens system, a 2-dimensional image of a display can be converted into a 3-dimensional autostereoscopic image, which can be achieved by using a mixture with high optical anisotropy (Δn). In the case of a TN (Saudi-Helfrich) unit, a medium that promotes the following advantages in the unit is required:-Extended nematic phase range (especially reduced to low temperatures)-Switching ability at extremely low temperatures ( Outdoor use, automotive, avionics)-Improved UV radiation resistance (longer life)-Low threshold voltage. The medium obtained from the prior art cannot achieve these advantages while retaining other parameters. In the case of super-twist (STN) cells, a medium that promotes greater multiplexing and / or lower threshold voltages and / or wider nematic phase ranges (especially at low temperatures) is needed. For this purpose, there is an urgent need to further widen the parameter tolerances (clear point, smectic-nematic or melting point, viscosity, dielectric parameters, elasticity parameters) that are available. One of the most important characteristics of modern LCDs is the correct reproduction of moving images. If the response speed of the liquid crystal medium used is too slow, this will cause unwanted artifacts in the display of these contents. The physical parameters that basically determine the response time of the liquid crystal mixture are the rotational viscosity γ ₁ and the elastic constant. The latter is also particularly important to ensure the good black state of the LCD. However, in general, the clear point of the mixture is observed and therefore the rotational viscosity of the mixture also increases as the elastic constant increases, meaning that the response time cannot be improved. Especially in the case of LC displays for TV and video applications (such as LCD TVs, monitors, PDAs, notebook computers, game consoles), the response time needs to be significantly reduced. The reduction in the layer thickness d ("cell gap") of the LC medium in the LC unit theoretically results in a faster response time, but requires the LC medium to have a higher birefringence Δn to ensure sufficient light retardation (d ^. Δn) . However, LC materials with high birefringence known from the prior art usually also have high rotational viscosity, which in turn has an adverse effect on response time. Therefore, there is still a great need for liquid crystal media with good reliability characteristics, such as high voltage holding ratio (VHR), which do not exhibit these characteristics or only to a lesser extent. The present invention is based on the goal of providing a medium, especially to this type of IPS, FFS, HB (= high brightness) -FFS, PS (= polymer stabilized) -FFS, PS-IPS displays, which have the above indicated Desired characteristics and do not present the disadvantages indicated above or only to a reduced extent. In particular, LC media should have fast response time, low rotational viscosity, and relatively high birefringence. In addition, the LC medium should have a high-definition clear point and excellent low-temperature stability (LTS). However, according to the present application, an IPS or FFS effect with a dielectrically positive liquid crystal medium with uniform alignment is better. Liquid crystal media with positive dielectric anisotropy have been disclosed for IPS and FFS displays. Some examples will be given below. WO 2012/079676 A1 discloses a liquid crystal medium with high positive dielectric anisotropy. Publication WO 2013/182271 A1 discloses a liquid crystal medium with positive dielectric anisotropy, which is additionally stabilized by Tinuvin 770®. Polymerizable piperidine derivatives as disclosed herein in WO 2016/116119 A1 have been proposed as additives in polymerizable liquid crystal media. This effect has an LC phase in industrial applications in electro-optical display elements, which must meet a variety of requirements. Particularly important in this article are the chemical resistance to moisture, air, and physical influences such as radiation in the heat, infrared, visible, and ultraviolet regions, as well as direct current (DC) and alternating current (AC) electric fields. As used herein, the term MLC display covers any matrix display with integrated non-linear elements, that is, in addition to the active matrix, the display also has passive elements such as a rheostat or a diode (MIM = metal-insulator-metal). This type of MLC display is particularly suitable for TV applications, monitors and laptops or for displays with high information density, such as in automobile manufacturing or aircraft construction. In addition to the issues related to the angular dependence of the contrast and the response time, the specific resistance of the liquid crystal mixture is not high enough, which causes difficulties in MLC displays [TOGASHI, S., SEKIGUCHI, 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, page 141 and below, Paris; STROMER, M., Proc. Eurodisplay 84, September 1984: Design of Thin Film Transistors for Matrix Addressing of Television Liquid Crystal Displays, p. 145 and below, Paris]. As the resistance decreases, the contrast of the MLC display deteriorates. Since the specific resistance of a liquid crystal mixture usually decreases with the lifetime of an MLC display due to interaction with the internal surface of the display, high (initial) resistance is extremely important for displays that must have acceptable resistance values over a long period of operation. Such media are particularly useful for electro-optic displays with active matrix addressing for IPS or FFS displays. It has now been found that this goal can be achieved if an LC medium containing one or more compounds of formula I is used.

Surprisingly, it has been found that it is possible to obtain a liquid crystal display, which has a low threshold voltage with short response time, a sufficiently wide nematic phase, favorable birefringence (Δn), and at the same time high transmittance, particularly in IPS and FFS displays. Good stability by heating and decomposition by UV exposure, and stable high VHR, P-Sp-, in the case of using a nematic liquid crystal mixture containing at least one compound of the following formula I or a polymer containing its polymerized form (A ² -Z ² -A ¹ ) _m1 -Z ¹ -TI wherein the groups are independent of each other and each time the same or different has the following meanings T is selected from the group of the formula R ^g H or a linear or branched alkyl or alkoxyalkyl group having 1 to 10 C atoms, preferably 1 to 6 C atoms, and preferably 1 to 4 C atoms, or benzyl , Preferably H, R ^a , R ^b , R ^c , ^Rd having 1 to 10 C atoms, preferably 1 to 6 C atoms, and very preferably a straight or branched chain having 1 to 4 C atoms Alkyl, P vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane or epoxy, preferably acrylate, methacrylate, fluoroacrylate, chloroacrylate, and more preferably an acrylate or methacrylate, preferably methyl methacrylate, Sp spacer group or a single bond, A ^1, A ² having 4 to 30 ring atoms an alicyclic group, heteroaryl A cyclic group, an aromatic group or a heteroaromatic group, which may also contain a fused ring and optionally substituted by one or more groups L or R- (A ³ -Z ³ ) _m ^2- , and in A ¹ and A ² One of them may also represent a single bond. A ³ has an alicyclic group, heterocyclic group, aromatic group, or heteroaromatic group having 4 to 30 ring atoms, it may also contain fused rings and, as appropriate, one or more groups ^{L, Z 1 -O -, - S} -, - CO- -CO-O -, - O- CO -, - O-CO-O -, - OCH 2 -, - CH 2 O -, - SCH 2 -, - CH 2 S -, - CF 2 O -, - OCF _2- , -CF ₂ S-, -SCF ₂ -,-(CH ₂ ) _n- , -CF ₂ CH _2- , -CH ₂ CF ₂ -,-(CF ₂ ) _n- , -CH = CH-, -CF = CF-, -CH = CF-, -CF = CH-, -CºC-, -CH = CH-CO-O-, -O-CO-CH = CH-, -CH ₂ -CH ₂ -CO -O-, -O-CO-CH ₂ -CH _2- , -CR ⁰⁰ R ⁰⁰⁰ -or single bond, the restriction is that if m1 is 0, then Z ¹ is a single bond, Z ² , Z ³ -O- , -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -OCH _2- , -CH ₂ O-, -SCH _2- , -CH ₂ S- , -CF ₂ O-, -OCF _2- , -CF ₂ S-, -SCF ₂ -,-(CH ₂ ) _n- , -CF ₂ CH _2- , -CH ₂ CF ₂ -,-(CF ₂ ) _n- , -CH = CH-, -CF = CF-, -CH = CF-, -CF = CH-, -CºC-, -CH = CH-CO-O-, -O-CO-CH = CH- , -CH ₂ -CH ₂ -CO-O-, -O-CO-CH ₂ -CH _2- , -CR ⁰⁰ R ⁰⁰⁰ -or single bond, R ⁰⁰ , R ⁰⁰⁰ H or one having 1 to 12 C atoms Alkyl, R P-Sp-, H, F, Cl, CN, or straight, branched, or cyclic alkyl having 1 to 25 C atoms, in which one or more non-adjacent CH ₂ -groups Optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, in a manner such that O And / or S atoms are not directly connected to each other, and one or more H atoms thereof are optionally replaced by F, Cl or P-Sp-, or the group T, L P-Sp-, F, Cl, CN or A linear, branched or cyclic alkyl group having 1 to 25 C atoms, one or more non-adjacent CH ₂ -groups, optionally from -O-, -S-, -CO-, -CO-O -, -O-CO-, -O-CO-O- are replaced in such a way that O and / or S atoms are not directly connected to each other, and one or more of the H atoms are each optionally F, Cl or P- Sp-substitution, or a group selected from Formulas 1, 2 and 3, m1 0, 1, 2, 3 or 4, m2 0, 1, 2, 3 or 4, and n 1, 2, 3 or 4. The present invention relates to a liquid crystal medium having a nematic phase and a dielectric anisotropy (Δε) of 1.5 or more, which is characterized in that it contains one or more compounds of formula I as described above or below or contains one or Polymers of compounds of formula I in various polymeric forms.

The invention more specifically relates to a liquid crystal medium comprising-a polymerizable component A) comprising one or more polymerizable compounds, at least one of which is a compound of formula I, and- The liquid crystal component B), hereinafter also referred to as "LC host mixture", contains one or more liquid crystal priming groups or liquid crystal compounds, and preferably consists of them. The liquid crystal component B) of the liquid crystal medium according to the present invention is also referred to as "LC host mixture" hereinafter, and preferably contains one or more, preferably at least two, mesogen or LC selected from non-polymerizable low molecular weight compounds Compound. Furthermore, the invention relates to a liquid crystal medium as described above and below, wherein the LC host mixture or component B) comprises at least one mesogen or LC compound containing an alkenyl group. Furthermore, the invention relates to a liquid crystal medium or an LC display as described above and below, in which the polymerizable compound of the compound of formula I or component A) is polymerized. In addition, the present invention relates to a method for preparing a liquid crystal medium as described above and below, which method comprises the steps of: combining one or more mesogens or LC compounds or LC host mixture or LC group as described above and below Sub-B) is mixed with one or more compounds of formula I and optionally with other LC compounds and / or additives. Such media are particularly useful for electro-optic displays with active matrix addressing for IPS or FFS displays. The medium according to the invention preferably further comprises one or more compounds selected from the group of compounds of formula II and compounds of formula III, preferably one or more compounds of formula II, more preferably one or more compounds of formula III, and most preferably another Or more compounds selected from the group of compounds of formula IV and compounds of formula V. The mixture according to the present invention exhibits an extremely wide nematic phase range at a clearing point ≥70 ° C, has a relatively high retention rate (VHR) value, a very favorable capacitance threshold, and at the same time at -20 ° C and -30 Good low temperature stability at ℃, and extremely low rotational viscosity. In addition, the mixture according to the invention is distinguished by a good ratio of clarification point and rotational viscosity and a relatively high positive dielectric anisotropy. Notably, the reliability of the mixture is improved. Very few image burns were observed. Even after extended use or similarly after standard burn-in tests such as accelerated light load, thermal or UV tests, the voltage retention rate is high. In one aspect, preferably, the dielectric anisotropy value of the liquid crystal medium according to the present invention is 2 or more, preferably 3.5 or more and 4.5 or more. On the other hand, its dielectric anisotropy is preferably 25 or less. In a preferred embodiment, the positive dielectric anisotropy of the liquid crystal medium according to the present invention is preferably in a range of 2.0 or more and 25 or less, more preferably 3.0 or more and 22 or less. Range, and most preferably in the range of 8.0 or more to 20 or less. All% by weight, the compound of formula I is preferably used at a concentration in the range of 0.0005 to 2% by weight, more preferably in the range of 0.001 to 1% by weight, particularly preferably in the range of 0.005 to 0.05% by weight Liquid crystal medium. The total content of polymerizable or polymerizable components in the liquid crystal medium according to the present invention is preferably less than 0.1% by weight, more preferably less than 0.05% by weight, and most preferably less than 0.02% by weight (200 ppm). The liquid crystal medium preferably comprises a) one or more compounds of formula I, b) one or more dielectrics selected from the group of compounds of formula II and compound III, preferably from a group of compounds having a dielectric anisotropy greater than 3 Positive compounds:Where R² Represents an alkyl group, alkoxy group, fluorinated alkyl group or fluorinated alkoxy group having 1 to 7 C atoms, an alkenyl group, alkenyloxy group, alkoxyalkyl group, or fluorine group having 2 to 7 C atoms Alkenyl, and preferably represents alkyl or alkenyl, L^{twenty one} And L^{twenty two} Represents H or F, preferably L^{twenty one} Means F, X² Represents a 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-CH₂ CF₃ , -O-CH = CH₂ , -O-CH = CF₂ Or -CF₃ , Preferably F, Cl, CF₃ , -O-CH = CF₂ Or -OCF₃ , M represents 0, 1, 2 or 3, preferably 1 or 2 and particularly preferably 1, R³ Represents an alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy group having 1 to 7 C atoms, an alkenyl group, alkenyloxy group, alkoxyalkyl group or fluorine group having 2 to 7 C atoms Alkenyl, and preferably represents alkyl or alkenyl, L³¹ And L³² , Represent H or F independently of each other, preferably L³¹ Means F, X³ Represents a 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, F, Cl, -OCF₃ , -OCHF₂ , -O-CH₂ CF₃ , -O-CH = CF₂ , -O-CH = CH₂ Or -CF₃ , Excellent representation of F, Cl, -O-CH = CF₂ , -OCHF₂ Or -OCF₃ , Z³ Means -CH₂ CH₂ -, -CF₂ CF₂ -, -COO-, trans-CH = CH-, trans-CF = CF-, -CH₂ O- or single bond, preferably -CH₂ CH₂ -, -COO-, trans-CH = CH-, or single bond, and excellently represent -COO-, trans-CH = CH-, or single bond, and n represents 0, 1, 2, or 3, preferably 1, 2 or 3 and particularly preferably 1, and c) optionally one or more dielectric neutral compounds selected from the group of formulae IV and V:Where R⁴¹ And R⁴² , Independently of each other having R above according to formula II² Indicated meaning, preferably R⁴¹ Represents an alkyl group and R⁴² For alkyl or alkoxy, or R⁴¹ Represents alkenyl and R⁴² Represents an alkyl group, Z⁴¹ And Z⁴² , Independently of each other and if Z⁴¹ Occurs twice, then these groups also independently represent -CH₂ CH₂ -, -COO-, trans-CH = CH-, trans-CF = CF-, -CH₂ O-, -CF₂ O-, -C≡C- or a single bond, preferably one or more of them represents a single bond, and p represents 0, 1 or 2, preferably 0 or 1, and R⁵¹ And R⁵² Independently of each other for R⁴¹ And R⁴² One of the given meanings, and preferably represents an alkyl group having 1 to 7 C atoms, preferably represents an n-alkyl group, and particularly preferably represents an n-alkyl group having 1 to 5 C atoms, representing 1 to An alkoxy group having 7 C atoms is preferably an n-alkoxy group, particularly preferably an n-alkoxy group having 2 to 5 C atoms, and an alkoxy group having 2 to 7 C atoms, preferably having 2 to 4 C atom alkoxyalkyl, alkenyl or alkenyloxy, preferably alkenyloxy, Preferably Preferably, And if it exists, then Z⁵¹ To Z⁵³ Each independently represent -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, i and j each independently represent 0 or 1, (i + j) preferably represents 0, 1 or 2, more preferably represents 0 or 1 and most preferably Means 1. The liquid crystal medium according to the present application preferably has a nematic phase. Throughout this application and specifically against R¹ The definition of alkyl means alkyl, which may be straight or branched. Each of these groups is preferably a straight chain, and preferably has 1, 2, 3, 4, 5, 6, 7, or 8 C atoms, and correspondingly preferably methyl, ethyl, n- Propyl, n-butyl, n-pentyl, n-hexyl or n-heptyl. In the case where alkyl means a branched alkyl group, it preferably means 2-alkyl, 2-methylalkyl or 2- (2-ethyl) -alkyl, and more preferably 2-butyl ( = 1-methylpropyl), 2-methylbutyl, 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, especially 2-methylbutyl Group, 2-methylbutoxy 4-methylhexyl, 2-hexyl, 2-octyl, 2-nonyl, 2-decyl and 2-dodecyl. These groups are preferably 2-hexyl and 2-octyl. Individual branching groups, especially for R¹ (Which gives rise to a palmitic compound) is also referred to as a palmitic group in this application. Particularly preferred para-groups are 2-alkyl, 2-alkoxy, 2-methylalkyl, 2-methylalkoxy, 2-fluoroalkyl, 2-fluoroalkoxy, 2- (2-acetylene) -alkyl, 2- (2-acetylene) -alkoxy, 1,1,1-trifluoro-2-alkyl and 1,1,1-trifluoro-2-alkoxy. For example, particularly preferred para-groups are 2-butyl (= 1-methylpropyl), 2-methylbutyl, 2-methylpentyl, 3-methylpentyl, 2- Ethylhexyl, 2-propylpentyl, especially 2-methylbutyl, 2-methylbutoxy, 2-methylpentoxy, 3-methylpentoxy, 2-ethylhexyl Methyl, 1-methylhexyloxy, 2-octyloxy, 2-oxo-3-methylbutyl, 3-oxo-4-methylpentyl, 4-methylhexyl, 2-hexyl, 2-octyl, 2-nonyl, 2-decyl, 2-dodecyl, 6-methoxyoctyloxy, 6-methyloctyloxy, 6-methyloctyloxy, 5- Methylheptyloxycarbonyl, 2-methylbutyryloxy, 3-methylpentyloxy, 4-methylhexyloxy, 2-chloropropanyloxy, 2-chloro-3-methyl Butanyloxy, 2-chloro-4-methylpentamyloxy, 2-chloro-3-methylpentamyloxy, 2-methyl-3-oxopentyl, 2-methyl-3- Oxahexyl, 1-methoxypropyl-2-oxy, 1-ethoxypropyl-2-oxy, 1-propoxypropyl-2-oxy, 1-butoxypropyl -2-oxy, 2-fluorooctyloxy, 2-fluorodecyloxy, 1,1,1-trifluoro-2-octyloxy, 1,1,1-trifluoro-2-octyl, 2-fluoromethyloctyloxy. Excellent are 2-hexyl, 2-octyl, 2-octyloxy, 1,1,1-trifluoro-2-hexyl, 1,1,1-trifluoro-2-octyl, and 1,1,1 -Trifluoro-2-octyloxy. Compounds of formula I are prepared according to WO 2016/116119 A1 or are commercially available. In addition, the present invention relates to the use of a liquid crystal mixture and a liquid crystal medium according to the present invention in IPS and FFS displays, especially in a liquid crystal-containing medium, for improving the voltage-holding-ratio. In addition, the present invention relates to a liquid crystal display containing a liquid crystal medium according to the present invention, particularly an IPS or FFS display, and particularly preferably an IPS display. The display according to the present invention is preferably an active matrix (a ctivem atrix LCD (Referred to as AMD), which is preferably addressed by a thin film transistor (TFT) matrix. However, the liquid crystal according to the invention can also be used advantageously in displays with other known addressing methods. Furthermore, the present invention relates to a method for preparing a liquid crystal medium according to the present invention by mixing one or more compounds of formula I with one or more low molecular weight liquid crystal compounds, or a liquid crystal mixture, and optionally with other liquid crystal compounds and / Or additives are mixed to obtain a liquid crystal medium having a nematic phase and a dielectric anisotropy (Δε) of 1.5 or more. The following meanings apply above and below: As used herein, the terms "reactive mesogen" and "RM" should be understood to mean a polymer containing One or more functional compounds. These groups are also called "polymerizable groups" or "P". Unless stated otherwise, the term "polymerizable compound" as used herein is understood to mean a polymerizable monomer compound. As used herein, the term "low molecular weight compound" is understood to mean a monomer and / or a compound that is not prepared by a polymerization reaction, as opposed to a "polymeric compound" or "polymer." The term "halogen" means fluorine, chlorine or bromine, preferably fluorine or chlorine and especially fluorine. The term halogenation is used similarly. As used herein, the term "non-polymerizable compound" is understood to mean a compound that does not contain a functional group suitable for polymerizing under conditions commonly used in RM polymerization reactions. The term "liquid crystal base" is known to those skilled in the art and is described in the literature, and means that due to its anisotropy of attraction and repulsion interactions, it basically contributes to liquid crystal (LC) in low molecular weight or polymer Groups generated by the phase. The compound containing a mesogen (the mesogen) does not need to have a liquid crystal phase per se. It is also possible that the mesogen compound exhibits a liquid crystal phase behavior only after being mixed with other compounds and / or after a polymerization reaction. Typical liquid crystal primitives are, for example, rigid rod-shaped or disc-shaped cells. An overview of terms and definitions used in connection with mesogens or liquid crystal compounds is described in Pure Appl. Chem. 73 (5), 888 (2001) and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368. The term "spacer" or simply "spacer", also referred to as "Sp" above and below, is known to those 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 means a flexible group that connects the mesogen and the polymerizable group to each other in the polymerizable mesogen compound. Although the mesogenic group generally contains a ring, the spacer group is generally an acyclic system, that is, in the form of a chain, and the chain may be a branched chain. The term chain is used, for example, for alkylene. On-chain and in-chain generally include substitutions such as by -O- or -COO-. In functional group terminology, a spacer (spacer) is a linking group between the functional structural parts of a molecule, which contributes to the specific spatial flexibility between these parts. In a preferred embodiment, the spacer represents an alkylene (such as-(CH₂ )_n And n = 1 to 10) or alkyleneoxy, preferably having 2 to 5 carbon atoms. Above and below,Represents a trans-1,4-cyclohexyl ring, andRepresents a 1,4-phenylene ring. 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, for example, Formula I or a reactive mesogen. The term "liquid crystal mixture" (or "host mixture") is intended to mean a composition consisting only of non-polymerizable low molecular weight compounds, preferably two or more liquid crystal compounds and optionally other additives, such as palmitic dopants Or a liquid crystal mixture composed of a stabilizer. Particularly preferred are liquid crystal mixtures and liquid crystal media having a nematic phase, especially a nematic phase at room temperature. In addition, there are preferred embodiments of the additives of formula I. Preferably, m1 in Formula I is 0 or 1, and most preferably 0. More preferred are compounds of formula I selected from the group of compounds of formula wherein T is a group selected from formulaWhere R^{a , b , c , d} Independently is a straight or branched chain alkyl group having 1 to 10 C atoms. Preferably, Z in Formula I¹ Represents -CO-O-, -O-CO-, or a single bond, preferably -CO-O- or a single bond. Preferably, Z in Formula I² And Z³ Represents -CO-O-, -O-CO-, or a single bond, preferably a single bond. Preferably, P in Formula I is an acrylate or methacrylate group. Preferably, Sp in Formula I is a single bond. Preferably, A in Formula I³ Represents an aromatic or heteroaromatic group having 6 to 24 ring atoms, which may also contain a fused ring and is optionally substituted with one or more groups L. Excellently, A in Formula I³ Represents benzene or naphthalene, optionally substituted with one or more groups L. Preferably, A in Formula I¹ And A² Represents an aromatic or heteroaromatic group having 6 to 24 ring atoms, which may also contain a fused ring and optionally one or more groups L or R- (A³ -Z³ )_m2 -Replace, or A¹ Is a single key. Excellently, A in Formula I¹ And A² Represents benzene, cyclohexyl, naphthalene, phenanthrene or anthracene, optionally via one or more groups L or R- (A³ -Z³ )_m2 -Replace, or A¹ Is a single key. Preferably,-(A in formula I² -Z² -A¹ )_m1 -Represents benzene, diphenylene, paraphenylene triphenyl (1,4-diphenylbenzene), metaphenylene triphenylene (1,3-diphenylbenzene), naphthyl, 2-phenyl-naphthyl, Phenanthrene or anthracene, both of which are optionally substituted with one or more groups L. Excellently,-(A² -Z² -A¹ )_m1 -Represents biphenylene, terphenylene, or metaphenylene, all of which are optionally substituted with one or more groups L. Preferred group- (A² -Z² -A¹ )_m1 -Selected from Where L is as defined in Formula I or has one of the preferred meanings described above and below, r is 0, 1, 2, 3, or 4, s is 0, 1, 2, or 3, and t is 0, 1 Or 2 and u is 0, 1, 2, 3, 4 or 5. Especially preferred are groups of the formulae A1, A2, A3, A4 and A5. Preferred compounds of formula I are selected from the following subformulas Of which P, Sp, R^{a - d} ,Z¹ , L and R are as defined in Formula I or have one of the preferred meanings as described above and below, R^e Is an alkyl group having 1 to 12 C atoms, r is 0, 1, 2, 3, or 4 and s is 0, 1, 2, or 3. Preferably, Z in formulae I and I-1 to I-45¹ Represents -CO-O-, -O-CO-, or a single bond, preferably -CO-O- or a single bond. Preferably, P in formulae I and I-1 to I-45 is an acrylate or a methacrylate. Preferably, Sp in formulae I and I-1 to I-45 is a single bond. Preferably, R in formulae I and I-1 to I-45^a , R^b , R^c And R^d Is methyl. Preferably, R in formula I^g Is H. The preferred structures among I-1 to I-45 are structures I-1 and I-23, and especially structures I-23. Better compounds of formula I and its sub-formulas I-1 to I-45 are independently selected from the following preferred embodiments, including any combination thereof:-the compounds contain exactly one polymerizable group (designated as group P ),-P is an acrylate or methacrylate,-Sp is a single bond,-Sp is selected from-(CH when different from a single bond)₂ )_a -O-,-(CH₂ )_a -CO-O-,-(CH₂ )_a -And- (CH₂ )_a -O-CO-, where applicable, 2, 3, 4, 5, or 6, and the O atom or CO- group is connected to the next ring A2 or the group T,-R^a , R^b , R^c And R^d Is methyl,-R^e Methyl, ethyl, n-propyl, isopropyl, third butyl, n-butyl or n-pentyl,-R^g Is H,-m1 is 0, 1, or 2,-m2 is 0, 1, or 2,-Z¹ Represents -CO-O-, -O-CO- or a single bond, preferably -CO-O-,-Z² Represents -CO-O-, -O-CO- or a single bond, preferably a single bond,-L represents F, Cl, CN or optionally fluorinated alkyl or alkoxy group having 1 to 6 C atoms Base, preferably F, Cl, CN, CH₃ , OCH₃ OCF₃ OCF₂ H or OCFH₂ , Preferably F, one or more of -L represents the group T, -r is 0 or 1, -s is 0, -t is 0, and -u is 0, 1, or 2. In a preferred embodiment of the present invention, the liquid crystal medium comprises one or more dielectric positive compounds having a dielectric anisotropy greater than 3, which are selected from the group of compounds of formulas II-1 and II-2:Where the parameters have the respective meanings indicated above according to Formula II, and L^{twenty three} And L^{twenty four} Represent H or F independently of each other, preferably L^{twenty three} Represents F, and And in the case of Formulas II-1 and II-2, X² Preferably F or OCF₃ , Especially preferably represents F, and in the case of Formula II-2, And / or a group selected from compounds of formulas III-1 and III-2:Where the parameters have the meaning given according to formula III, and as an alternative to or in addition to compounds of formula III-1 and / or III-2, the medium according to the invention may contain one or more of formula III-3 Compounds,Where the parameters have the respective meanings indicated above, and the parameter L³¹ And L³² Represent H or F independently of each other and independently of other parameters. The liquid crystal medium preferably comprises a compound selected from the group of compounds of formulae II-1 and II-2, where L^{twenty one} And L^{twenty two} And / or L^{twenty three} And L^{twenty four} Both represent F. In a preferred embodiment, the liquid crystal medium comprises a compound selected from the group of compounds of formulae II-1 and II-2, where L^{twenty one} , L^{twenty two} , L^{twenty three} And L^{twenty four} Both represent F. The liquid crystal medium preferably contains one or more compounds of formula II-1. The compound of formula II-1 is preferably selected from the group of compounds of formula II-1a to II-1e, preferably formula II-1a and / or II-1b and / or II-1d, and preferably one or more formulas II-1a and / or II-1d or II-1b and / or II-1d, most preferably compounds of formula II-1d: Where the parameters have the respective meanings indicated above, and the parameter L²⁵ And L²⁶ Represent H or F independently of each other and independently of other parameters, and preferably in formulas II-1a and II-1b, L^{twenty one} And L^{twenty two} Both represent F, and in Formulas II-1c and II-1d, L^{twenty one} And L^{twenty two} Both represent F, and / or L^{twenty three} And L^{twenty four} Both represent F, and in Formula II-1e, L^{twenty one} , L^{twenty two} And L^{twenty three} Means F. The liquid crystal medium preferably comprises one or more compounds of formula II-2, and these compounds are preferably selected from the group of compounds of formulas II-2a to II-2k, preferably one or more of formulas II-2a, II-2h, Compounds of each of II-2k and / or II-2j: Where the parameters have the respective meanings indicated above, and L²⁵ To L²⁸ Represent H or F independently of each other, preferably L²⁷ And L²⁸ Both represent H, particularly preferably L²⁶ Indicates H. The liquid crystal medium preferably comprises a compound selected from the group of compounds of the formulae II-2a to II-2k, where L^{twenty one} And L^{twenty two} Both represent F, and / or L^{twenty three} And L^{twenty four} Both represent F. In a preferred embodiment, the liquid crystal medium comprises a compound selected from the group of compounds of formulae II-2a to II-2k, where L^{twenty one} , L^{twenty two} , L^{twenty three} And L^{twenty four} Both represent F. Particularly preferred compounds of formula II-2 are compounds of the following formulae, and particularly preferred are compounds of formula II-2a-1, II-2h-1 and / or II-2k-1 and / or II-2j--1 Compound: Where R² And X² Has the meaning indicated above, and X² F is preferably represented. The liquid crystal medium preferably contains one or more compounds of formula III-1. The compound of formula III-1 is preferably selected from the group of compounds of formulas III-1a to III-1j, and is preferably selected from the group of formulas III-1c, III-1f, III-1g and III-1k: Where the parameters have the meanings given above, and preferably where the parameters have the respective meanings indicated above, the parameter L³³ And L³⁴ Represent H or F independently of each other and independently of other parameters, and the parameter L³⁵ And L³⁶ Represent H or F independently of each other and independently of other parameters. The liquid crystal medium preferably contains one or more compounds of formula III-1c, and these compounds are preferably selected from the group of compounds of formula III-1c-1 to III-1c-5, preferably formula III-1c-1 and / Or a compound of III-1c-2, preferably a compound of formula III-1c-1:Where R³ Has the meaning indicated above. The liquid crystal medium preferably comprises one or more compounds of the formula III-1f, and these compounds are preferably selected from the group of compounds of the formulae III-1f-1 to III-1f-6, preferably of the formula III-1f-1 and / Or a compound of III-1f-2 and / or III-1f-3 and / or III-1f-6, more preferably a compound of formula III-1f-3 and / or III-1f-6, more preferably formula III Compound of -1f-6:Where R³ Has the meaning indicated above. The liquid crystal medium preferably comprises one or more compounds of formula III-1g, these compounds are preferably selected from the group of compounds of formula III-1g-1 to III-1g-5, more preferably compounds of formula III-1g-3:Where R³ Has the meaning indicated above. The liquid crystal medium preferably comprises one or more compounds of formula III-1h, these compounds are preferably selected from the group of compounds of formula III-1h-1 to III-1h-3, more preferably compounds of formula III-1h-3 :Where the parameter has the meaning given above, and X³ F is preferably represented. The liquid crystal medium preferably comprises one or more compounds of formula III-1i, these compounds are preferably selected from the group of compounds of formula III-1i-1 and III-1i-2, more preferably compounds of formula III-1i-1 : Where the parameter has the meaning given above, and X³ F is preferably represented. The liquid crystal medium preferably comprises one or more compounds of the formula III-1j. These compounds are preferably selected from the group of compounds of the formulae III-1j-1 and III-1j-2, more preferably the compounds of the formula III-1j-1 :The parameters have the meanings given above. The liquid crystal medium preferably comprises one or more compounds of formula III-1k, these compounds are preferably selected from the group of compounds of formula III-1k-1 and III-1k-2, and are preferably compounds of formula III-1k-1 : The parameters have the meanings given above. The liquid crystal medium preferably contains one or more compounds of formula III-2. The compound of formula III-2 is preferably selected from the group of compounds of formulas III-2a and III-2b, more preferably a compound of formula III-2b:Where the parameters have the respective meanings indicated above, and the parameter L³³ And L³⁴ Represent H or F independently of each other and independently of other parameters. The liquid crystal medium preferably comprises one or more compounds of formula III-2a, and these compounds are preferably selected from the group of compounds of formula III-2a-1 to III-2a-6: Where R³ Has the meaning indicated above. The liquid crystal medium preferably comprises one or more compounds of formula III-2b, which compounds are preferably selected from the group of compounds of formula III-2b-1 to III-2b-4, more preferably compounds of formula III-2b-4 : Where R³ Has the meaning indicated above. And as an alternative to or in addition to the compounds of formula III-1 and / or III-2, the medium according to the invention may comprise one or more compounds of formula III-3,The parameters have the respective meanings indicated above according to formula III. These compounds are preferably selected from the group of formulae III-3a and III-3b:Where R³ Has the meaning indicated above. In a more preferred embodiment, the liquid crystal medium contains one or more compounds of formula III-1h-3 and one or more compounds of formula III-1j-1 in addition to the compound of formula I and compound of formula II. The liquid crystal medium according to the present invention preferably contains one or more dielectric neutral compounds having a dielectric anisotropy in the range of -1.5 to 3. In this application, these elements include their respective isotopes. In particular, one or more H of these compounds may be replaced by D, and in some embodiments, this is also particularly preferred. The corresponding high degree of deuteration of the corresponding compounds can, for example, detect and identify the compounds. In some cases, this is extremely helpful, especially in the case of compounds of formula I. In the present application, an alkyl group particularly preferably represents a linear alkyl group, especially CH₃ -, C₂ H₅ -,n -C₃ H₇ -,n -C₄ H₉ -orn -C₅ H₁₁ -, And alkenyl particularly preferably represents CH₂ = CH-,E -CH₃ -CH = CH-, CH₂ = CH-CH₂ -CH₂ -,E -CH₃ -CH = CH-CH₂ -CH₂ -orE -(n -C₃ H₇ ) -CH = CH-. In another preferred embodiment, the medium comprises one or more compounds of formula IV-AWhere R⁴¹ Represents an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkyl group having 2 to 7 C atoms, preferably an n-alkyl group, particularly preferably 2, 3, 4, or 5 C atoms Alkenyl, and R⁴² 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, wherein the group It is preferably an unsubstituted alkenyl group having 2 to 5 C atoms, and preferably 2, 3 or 4 C atoms, more preferably a vinyl group or a 1-propenyl group, and especially a vinyl group. In a particularly preferred embodiment, the medium comprises one or more compounds of formula IV selected from the group of compounds of formula IV-1 to IV-4, preferably compounds of formula IV-1,Wherein alkyl and alkyl 'independently represent an alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms, alkenyl and alkenyl' independently represent each other to have 2 to 5 C Atom, preferably an alkenyl group having 2 to 4 C atoms, particularly preferably 2 C atoms, alkenyl 'preferably means having 2 to 5 C atoms, preferably 2 to 4 C atoms, especially Alkenyl having 2 to 3 C atoms is preferred, and alkoxy means an alkoxy having 1 to 5 C atoms, preferably 2 to 4 C atoms. 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. In another preferred embodiment, the medium comprises one or more compounds of formula V. The medium according to the present invention preferably comprises the following compounds at a total concentration indicated as follows: 0.001-1 to 1% by weight of one or more compounds of formula I, and 5-60% by weight of one or more compounds of formula II, which are preferably selected from the formula Groups of compounds II-1 and II-2, and / or 5-25% by weight of one or more compounds of formula III, and / or 5-60% by weight of one or more compounds of formula IV, and / or 3-25 One or more compounds of formula V by weight, wherein the total content of all compounds of formula I and compounds of formulas II to V (which are present in the medium) is preferably 95% or more, more preferably 97% or more, and The best is 100%. The conditions for total content preferably apply to all media according to the present application. In another preferred embodiment, the medium according to the present invention further preferably comprises one or more dielectric neutral compounds, which compounds are preferably selected from a total concentration of 5% or more to 90% or less, more A group of compounds of formulae IV and V within the range of 10% or more to 80% or less, particularly preferably 20% or more to 70% or less. In a particularly preferred embodiment, the medium according to the invention comprises: one or more total concentrations in the range of 15% by weight or higher to 65% or lower, preferably 30% or higher to 55% or Compounds of formula II in lower ranges, and / or one or more compounds of formula III with a total concentration in the range of 5% or higher to 30% or lower. In a preferred embodiment of the present invention, the concentration of the compound of formula II in the medium is 15% by weight or more and 65% or less, more preferably 15% or more and 60% or less, and more preferably 20%. % Or higher to 55% or lower, and preferably in a range of 25% or higher to 40% or lower. The present invention also relates to an electro-optical display or an electro-optical module containing a liquid crystal medium according to the present invention. An electro-optic display based on the IPS or FFS effect, preferably based on the IPS effect, and particularly a display addressed by means of an active matrix addressing device. Therefore, the present invention also relates to the use of a liquid crystal medium according to the present invention in an electro-optical display or in an electro-optical module, and to a method for preparing a liquid crystal medium according to the present invention, which is characterized in that one or more compounds of formula I One or more compounds of formula II and optionally other compounds and additives are mixed. In another preferred embodiment, the medium comprises one or more compounds of formula IV selected from the group of compounds of formulae IV-2 and IV-3,Wherein alkyl and alkyl 'independently represent an alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms, and an alkoxy group represents 1 to 5 C atoms, preferably 2 to An alkoxy group of 4 C atoms. In another preferred embodiment, the medium comprises one or more compounds of formula V, selected from the group of compounds of formulas V-1 and V-2, preferably of formula V-1, Where the parameter has the meaning given above according to formula V, and preferably, R⁵¹ Represents an alkyl group having 1 to 7 C atoms or an alkenyl group having 2 to 7 C atoms, and R⁵² Represents 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, and particularly preferably an alkyl group . In another preferred embodiment, the medium comprises one or more compounds of formula V-1 selected from the group of compounds of formula V-1a and V-1b,Where alkyl and alkyl 'independently represent an alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms, and an alkenyl group represents 2 to 7 C atoms, preferably 2 to 7 Alkenyl of 5 C atoms. In addition to the compounds of the formulae I to V, other components may also be present, for example in an amount of up to 45% of the entire mixture, but preferably up to 35%, especially up to 10%. The medium according to the present invention may optionally include a dielectric negative component. The total concentration of the medium is preferably 20% or lower, and more preferably 10% or lower, based on the entire medium. In a preferred embodiment, the liquid crystal medium according to the present invention comprises 25% or more to 65% or less, preferably 30% or more to 60% or less, particularly preferably, based on the entire mixture. 35% or higher to 55% or lower compounds of formula II and / or III, and 5% or higher to 60% or lower, preferably 25% or higher to 55% or lower, especially Preferably, the compound of formula IV and / or V is 35% or more to 55% or less. The liquid crystal medium according to the present invention may contain one or more palmitic compounds. Particularly preferred embodiments of the present invention satisfy one or more of the following conditions, where acronyms (abbreviations) are explained in Tables A to C and illustrated by examples in Table D. Preferably, the medium according to the present invention satisfies one or more of the following conditions. i. The birefringence of the liquid crystal medium is 0.060 or higher, particularly preferably 0.070 or higher. ii. The birefringence of the liquid crystal medium is 0.200 or lower, and particularly preferably 0.180 or lower. iii. The birefringence of the liquid crystal medium is in the range of 0.090 or higher to 0.160 or lower. iv. The liquid crystal medium comprises one or more compounds of formula I, which are preferably selected from (sub) formulae I-1 and I-23, most preferably (sub) formulae I-23. v. The total concentration of the compound of formula II in the overall mixture is 25% or higher, preferably 30% or higher, and preferably in a range of 25% or higher to 49% or lower, particularly preferably In the range of 29% or more to 47% or more, and extremely preferably in the range of 37% or more to 44% or less. vi. The liquid crystal medium comprises one or more compounds of formula IV selected from the group of compounds of the formula: CC-nV and / or CC-n-Vm and / or CC-VV and / or CC-V-Vn and / or CC- nV-Vn, particularly preferably CC-3-V, and its concentration is preferably at most 60% or less, particularly preferably at most 50% or less; and CC-3-V1, which is additionally present as the case may be, The concentration is preferably at most 15% or less; and / or CC-4-V, the concentration thereof is preferably at most 40% or less, particularly preferably at most 30% or less. vii. These media include compounds of formula CC-nV, preferably formula CC-3-V, the concentration of which is preferably 1% or higher to 60% or lower, and the concentration is more preferably 3% or higher to 38. % Or lower. viii. The total concentration of the compound of formula CC-3-V in the overall mixture is preferably 15% or less, preferably 10% or less, or 20% or less, preferably 25% or more . In addition, the present invention relates to an electro-optic display having an active matrix based on IPS or FFS effect addressing, which is characterized in that it contains the liquid crystal medium according to the present invention as a dielectric. The nematic phase range of the liquid crystal mixture preferably has a width of at least 70 degrees. Rotational viscosity₁ It is preferably 350 mPa · s or lower, more preferably 250 mPa · s or lower, and especially 150 mPa · s or lower. The mixture according to the invention is suitable for all IPS and FFS-TFT applications using dielectric positive liquid crystal media, such as SG-FFS. The liquid crystal medium according to the present invention preferably consists almost entirely of 4 to 15, especially 5 to 12, and particularly preferably 10 or less compounds. These compounds are preferably selected from the group of compounds of the formulae I, II, III, IV, V, VI, VII, VIII and IX. The liquid crystal medium according to the present invention may optionally contain more than 18 compounds. In this case, it preferably contains 18 to 25 compounds. In a preferred embodiment, the liquid crystal medium according to the present invention mainly comprises a cyano-free compound, preferably consists essentially of it and most preferably consists almost entirely of it. In a preferred embodiment, the liquid crystal medium according to the present invention comprises a group selected from the group consisting of compounds of the formulae I, II and II, IV and V, preferably from the formulae I, II-1, II-2, IV and V A compound of the group of compounds; it preferably consists mainly of compounds of the formula, particularly preferably consists essentially of it and very preferably almost completely. The nematic phase of the liquid crystal medium according to the present invention is in each case preferably at least -10 ° C or lower to 70 ° C or higher, particularly preferably -20 ° C or lower to 80 ° C or higher, extremely It is preferably -30 ° C or lower to 85 ° C or higher and most preferably -40 ° C or lower to 90 ° C or higher. The expression "having a nematic phase" means in this context: on the one hand, no smectic phase and crystals are observed at the corresponding temperature and low temperature, and on the other hand, no clearness occurs when the self-nematic phase is heated. Research at low temperatures is performed in a flow-type viscometer at the corresponding temperature, and the inspection is performed by storing in a test unit with a cell thickness corresponding to electro-optical applications for at least 100 hours. If the storage stability at a temperature of -20 ° C in the corresponding test unit is 1000 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 clear point is measured in a capillary tube by conventional methods. In a preferred embodiment, the liquid crystal medium according to the present invention is characterized by optical anisotropy values in the medium to lower range. The birefringence value is preferably in the range of 0.075 or higher to 0.130 or lower, particularly preferably in the range of 0.085 or higher to 0.120 or lower and extremely preferably in the range of 0.090 or higher to 0.115 or lower Within range. 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 9.0 or higher to 22 or lower, more preferably 18 or lower, more preferably 10 or higher to 15 or lower, particularly preferably 4.0 or higher to 9.0 or lower, and very preferably 4.5 or higher to 8.0 or lower. The liquid crystal medium according to the present invention preferably has a relatively low threshold voltage (V₀ ) Value, which is 1.0 V or higher to 5.0 V or lower, preferably 2.5 V or lower, preferably 1.2 V or higher to 2.2 V or lower, particularly preferably 1.3 V or higher to 2.0 V or lower. In addition, the liquid crystal medium according to the present invention has a higher VHR value in a liquid crystal cell. In units newly filled at 20 ° C in units, the VHR of these media is greater than or equal to 95%, preferably greater than or equal to 97%, particularly preferably greater than or equal to 98% and extremely preferably greater than or equal to 99% And in a unit at 100 ° C in an oven after 5 minutes, these VHR values are greater than or equal to 90%, preferably greater than or equal to 93%, particularly preferably greater than or equal to 96% and extremely preferably greater than or equal to 98%. Generally speaking, liquid crystal media with a low addressing voltage or threshold voltage have a lower VHR than their liquid crystal media with a higher addressing voltage or threshold voltage, and vice versa. In each case, these preferred values of the individual physical properties are also preferably maintained by the combination of the media according to the invention with one another. In this application, the term "compounds / compound (s)" means one or more compounds unless explicitly indicated otherwise. In a preferred embodiment, the liquid crystal medium according to the present invention contains one or more formulas I compounds, preferably selected from the group of formulas I-1 and / or I-23, and / or one or more compounds of formula II, preferably selected from the formulas PUQU-nF, CDUQU-nF, APUQU-nF and PGUQU-nF And / or a group of CPUQU-nF, and / or one or more compounds of formula III, preferably selected from the group of formulas CCP-n-OT, CGG-nF and CGG-n-OD, and / or one or more formula IV And / or V compounds, preferably selected from the group of formulas CC-nV, CCP-nm, CCP-Vn, CCP-V2-n and CGP-nn, and / or preferably one or more as required Compounds of formula IV, preferably selected from formulas CC-nV, CC-n-Vm, CC-n-mVl and CC-nV-Vm, preferably CC-3-V, CC-3-V1, CC-4-V , CC-5-V, CC-3-2V1, and CC-VV compounds, particularly preferably selected from compounds CC-3-V, CC-3-V1, CC-4-V, CC-3-2V1 And CC-VV groups, most preferably the compound CC-3-V, and optionally the compound CC-4-V and / or CC-3-V1 and / or CC-3-2V1 and / or CC- VV And / or, as the case may be, mandatory, preferably one or more compounds of formula V, preferably selected from the group of formulas CCP-V-1 and / or CCP-V2-1. For the present invention, unless otherwise specified in individual cases Indicate, otherwise, the following definitions should be applied in conjunction with the description of the ingredients of the composition:-"Contains": The concentration of the ingredients in the composition is preferably 5% or higher, particularly preferably 10% or higher, and very preferably 20% or higher,-"consisting mainly of": the concentration of the ingredients in the composition is preferably 50% or higher, particularly preferably 55% or higher and extremely preferably 60% Or higher, "consisting essentially of": the concentration of the ingredients in question in the composition is preferably 80% or higher, particularly preferably 90% or higher and very preferably 95% or higher , And-"consisting almost entirely of": The concentration of the ingredients in the composition is preferably 98% or higher, particularly preferably 99% or higher and very preferably 100.0%. This also applies In a medium in the form of a composition having its ingredients, such compositions may be components and compounds, as well as components, As far as the concentration of an individual compound relative to the entire medium is concerned, the term includes means: the concentration of the compound in question is preferably 1% or higher, particularly preferably 2% or higher, and most preferably 4 % Or higher. For the present invention, "≤" means less than or equal to, preferably less than, and "≥" means greater than or equal to, preferably greater than. For the present inventionFor trans-1,4-cyclohexyl,Represents a mixture of cis-1,4-cyclohexyl and trans-1,4-cyclohexyl, andRepresents 1,4-phenylene. For the present invention, the expression "dielectrically positive compound" means a compound with Δε> 1.5, the expression "dielectrically neutral compound" means those compounds with -1.5 ≤ Δε ≤ 1.5, and the expression "dielectric negative compound" Means those compounds with Δε <-1.5. The host mixture used to measure Δε for dielectric positive and dielectric neutral compounds is ZLI-4792, and the host mixture used for dielectric negative compounds is ZLI-2857, both from Merck KGaA, Germany. The values of the individual compounds to be studied are obtained from changes in the dielectric constant of the host mixture after adding the compound to be studied and extrapolating to 100% of the compound used. The compound to be studied is dissolved in a host mixture in an amount of 10%. If the solubility of the substance is too low to be used for this purpose, the concentration is halved in the step until the study can be carried out at the required temperature. If necessary, the liquid crystal medium according to the present invention may further include additives in a usual amount, such as a stabilizer and / or a multi-color (for example, two-color) dye and / or a palm dopant. The amount of these additives used is preferably a total of 0% or higher to 10% or lower, and particularly preferably 0.1% or higher to 6% or lower, based on the amount of the entire mixture. The concentration of the individual compounds used is preferably from 0.1% or higher to 3% or lower. When specifying the concentration and range of liquid crystal compounds in a liquid crystal medium, the concentrations of these and similar additives are generally not considered. In a special embodiment, the liquid crystal medium according to the present invention may include a polymer precursor, which contains one or more reactive compounds, preferably a reactive mesogen, and if necessary, the liquid crystal medium further includes a common Amount of additives such as polymerization initiators and / or polymerization moderators. These additives are used in an amount of 0% or more to 10% or less, preferably 0.1% or more to 2% or less, based on the amount of the entire mixture. When specifying the concentration and range of the liquid crystal compound in the liquid crystal medium, the concentrations of these and similar additives are not taken into account. These compositions consist of a plurality of compounds mixed in a conventional manner, preferably 3 or more to 30 or less, particularly preferably 6 or more to 20 or less, and very preferably 10 Or more to 16 or less compounds. In general, the required amount of the components used in smaller amounts is dissolved in the components constituting the main ingredients of the mixture. This is advantageously performed at high temperatures. If the selected temperature is higher than the clearing point of the main components, it is particularly easy to observe the completion of the dissolution operation. However, it is also possible to prepare liquid crystal mixtures in other conventional ways, such as using a premix, or by a so-called "multi-bottle system". The mixture according to the present invention exhibits an extremely wide nematic phase range with a clearing point of 65 ° C or higher, an extremely favorable capacitance threshold, a relatively high retention value, and is excellent at both -30 ° C and -40 ° C. Low temperature stability. In addition, the mixture according to the invention has a low rotational viscosity γ₁ distinguish. It goes without saying that for those skilled in the art, the medium according to the invention may also include compounds in which, for example, H, N, O, Cl, F have been replaced by corresponding isotopes. The structure of the IPS liquid crystal display according to the present invention corresponds to a common geometric structure, as described, for example, in US 2001022569 A or US 2002030782 A. The liquid crystal phase according to the invention can be modified by means of suitable additives, in this way making it usable in, for example, any type of IPS and FFS LCD displays that have been disclosed so far. Table E below indicates possible dopants that can be added to the mixture according to the invention. If the mixture contains one or more dopants, the amount is from 0.01% to 4%, preferably from 0.1% to 1.0%. Additional stabilizers which may be added, for example to the mixture according to the invention, are preferably shown in Table F below in an amount of 0.001% to 6%, especially 0.1% to 3%. In a preferred embodiment of the present invention, the liquid crystal medium further comprises a stabilizer selected from phenols, more preferably a derivative selected from 2,6-di-tertiary-butylphenol, which is preferably the following table F Their phenols listed in, and are preferably selected from the group of formulas S-1 and S-2:Where R^S Represents an alkyl group, alkoxy group, fluorinated alkyl group or fluorinated alkoxy group having 1 to 9 C atoms, an alkenyl group, alkenyloxy group, and alkoxyalkyl group having 2 to 9 C atoms. Particularly preferred structures of formula S-1 or S-2 are compounds of formulas S-1-3 and S-2-3: For the purposes of the present invention, all concentrations are indicated in weight percent, unless explicitly stated otherwise, and refer to the respective whole mixture or the whole mixture components, unless explicitly indicated otherwise. In this context, the term "mixture" describes a liquid crystal medium. Unless otherwise explicitly indicated, all temperature values indicated in this application, such as melting point T (C, N), smectic phase (S) to nematic phase (N) transition T (S, N), and clear Point T (N, I) is indicated in degrees Celsius (° C), and all temperature differences are indicated in degrees (° or degrees) accordingly. For the present invention, the term "threshold voltage" refers to a capacitance threshold (V₀ ), Also known as the Freedericks threshold. Unless otherwise specifically indicated in each case, 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 are applicable to temperatures of 20 ° C, And Δn was measured at 436 nm, 589 nm, and 633 nm, and Δε was measured at 1 kHz. Herein, the dielectric anisotropy of the compound is determined by the following steps: 10% of the compound is dissolved in the liquid crystal host, and in each case the capacitance of the obtained mixture in at least one test unit is measured, and the unit of the test unit It is 20 µm thick with vertical and uniform surface alignment at 1 kHz. The measurement voltage is usually 0.3 V to 1.0 V, but it is always lower than the capacitance threshold of each liquid crystal mixture under study. Threshold voltage and all other electro-optical characteristics were measured using a test unit manufactured by Merck. The cell thickness of the test cell used to determine Δε is approximately 20 µm. The electrode has 1.13 cm² Round ITO electrode with area and guard ring. The orientation layer is used for vertical orientation (ε_|| ) Of SE-1211 from Nissan Chemicals, Japan and used for homogeneous orientation (ε_⊥ ) Of Polyimide AL-1054 from JSR, Japan. Using Solatron 1260 frequency response analyzer, using sine wave at 0.3 V_rms Voltage to determine capacitance. The light used for electro-optic measurement is white light. Equipment used herein is a DMS instrument available from Autronic-Melchers, Germany. The characteristic voltage has been measured under vertical observation. Thresholds were determined for 10%, 50%, and 90% relative contrast, respectively (V₁₀ ), Medium gray (V₅₀ ) And saturation (V₉₀ )Voltage. Unless otherwise indicated, a palmitic dopant is not added to the liquid crystal mixture used, but the latter is also particularly suitable for applications requiring such doping. Rotary viscosity was measured using a rotating permanent magnet method and flow viscosity in a modified Ubbelohde viscometer. For liquid crystal mixtures ZLI-2293, ZLI-4792 and MLC-6608 (all products from Merck KGaA, Darmstadt, Germany), the rotational viscosity values measured at 20 ° C were 161 mPa · s, 133 mPa · s, and 186 mPa · S with a flow viscosity value (ν) of 21 mm² · S^{- 1} , 14 mm² · S^{- 1} And 27 mm² · S^{- 1} . Unless explicitly stated otherwise, for practical purposes, the dispersion of materials can be conveniently characterized in the following manner used throughout this application. The birefringence value is measured at 20 ° C and at a fixed wavelength, using a modified Abbé refractometer on the side of the side that is in contact with the material to vertically align the surface. Birefringence values at specific wavelengths of 436 nm (spectral lines for individually selected low-pressure mercury lamps), 589 nm (sodium `` D '' line), and 633 nm (HE-Ne laser (in combination with attenuator / diffuser) Use to prevent damage to the eyes of the observer). In the table below, Δn is given at 589 nm and Δ (Δn) is given as Δ (Δn) = Δn (436 nm)-Δn (633 nm). Unless otherwise explicitly indicated, the following symbols are used: V₀ Threshold voltage, capacitance [V] at 20 ℃, n_e Abnormal refractive index measured at 20 ℃ and 589 nm, n_o Ordinary refractive index measured at 20 ° C and 589 nm, Optical anisotropy of Dn measured at 20 ° C and 589 nm, λ wavelength λ [nm], Dn (λ) measured at 20 ° C and wavelength λ Optical anisotropy, D (Dn) is defined as the change in optical anisotropy as follows: Dn (20 ℃, 436 nm)-Dn (20 ℃, 633 nm), D (Dn *) Relative change of anisotropy ": D (Dn) / Dn (20 ℃, 589 nm), e_^ Dielectric susceptibility perpendicular to the director at 20 ° C and 1 kHz, e_÷÷ At 20 ° C and 1 kHz, the dielectric susceptibility parallel to the director, De The dielectric anisotropy at 20 ° C and 1 kHz, T (N, I) or clp. Clear point [° C], n at Flow viscosity measured at 20 ℃ [mm² · S^{- 1} ], G₁ Rotational viscosity at 20 ℃ [mPa · s], k₁₁ Elastic constant, "tilt" deformation at 20 ° C [pN]; k_{twenty two} Elastic constant, "torsional" deformation at 20 ° C [pN], k₃₃ Elastic constant, "bending" deformation [pN] at 20 ° C, low-temperature stability of the phase measured by LTS in a test cell, VHR voltage retention (VHR ), The reduction of DVHR voltage retention, and S_rel The relative stability of VHR, the following examples are used to explain the invention without limiting the invention. However, it demonstrates to those skilled in the art the concept of a better mixture and the better used compounds and their respective concentrations and their combinations with each other. In addition, examples illustrate the available properties and combinations of properties. For the purposes of the present invention and in the following examples, the structure of a liquid crystal compound is indicated by means of an acronym, wherein the conversion of the chemical formula is carried out according to the following tables A to C. All groups 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 Both are straight-chain alkyl or alkylene, each having n, m and l C atoms in each case. Preferably, n, m and l are independently 1, 2, 3, 4, 5, 6, or 7. Table A shows the coding of the ring element of the nucleus of the compound, Table B lists the bridging units, and Table C lists the meaning of the symbols of the left and right end groups of the molecule. The acronym is composed of: the encoding of the ring element with the optionally linked group, followed by the encoding of the first hyphen and the left end group, and the encoding of the second hyphen and the right end group. Table D shows illustrative structures of the compounds along with their respective abbreviations.table A : Ring element table B : Bridging unit table C : End group Where n and m are integers, and the three dots "..." are placeholders for other abbreviations from this table. In addition to the compound of formula B, the mixture according to the invention preferably comprises one or more compounds as described below. Use the following abbreviations: (n, m, k, and l are each independently an integer, preferably 1 to 9, preferably 1 to 7, k and l may also be 0, and preferably 0 to 4, More preferably 0 or 2, and most preferably 2, n is preferably 1, 2, 3, 4 or 5, and in the combination "-nO-" it is preferably 1, 2, 3, or 4, and more preferably 2 or 4, m is preferably 1, 2, 3, 4 or 5, and in the combination "-Om" it is preferably 1, 2, 3 or 4, more preferably 2 or 4. The combination "-lVm" is more (It is preferably "2V1".)table D Exemplary, preferred dielectric positive compounds Exemplary, preferred dielectric neutral compounds Table E shows the palmitic dopants preferably used in the mixtures according to the invention.table E In a preferred embodiment of the invention, the medium according to the invention comprises one or more compounds selected from the group of compounds in Table E. Table F shows that in addition to the compounds of the formula I, stabilizers which can also be preferably used in the mixtures according to the invention. The parameter n herein represents an integer in the range of 1 to 12. In particular, the phenol derivative shown can be used as an additional stabilizer because it acts as an antioxidant.table F Where n is independently 1, 2, 3, 4, 5, 6, or 7.Examples The following examples explain the invention without limiting it in any way. However, physical characteristics allow those skilled in the art to understand what characteristics can be achieved and to what extent they can be modified. In particular, those skilled in the art are well aware of a combination of characteristics that can be better achieved. The following polymerizable stabilizers (polymerizable piperidine derivatives) are used:Source: Santa Cruz Biotechnology Inc. (CAS 31582-45-3) Synthetic examples of additives Exemplary compounds of formula I are synthesized as follows or according to WO 2016/116119 A1 (example).Synthesis example Compounds were prepared as followsRH - 2 .4-HydroxyTEMPO (8.00 g, 45.5 mmol) and 4- (dimethylamino) pyridine (0.30 g, 2.46 mmol) were added to 100 ml of DCM. After cooling to 2 ° C, triethylamine (25.00 ml, 180.35 mmol) was added to the above solution, and then 3-bromo-propanyl chloride (6.00 ml, 50.6 mmol) was added dropwise to 50 ml of DCM. After the addition was complete, the reaction mixture was allowed to warm to room temperature. After completing the conversion indicated by TLC, an aqueous ammonium chloride solution was added. The aqueous phase was extracted with DCM. The organic phases were combined and dried over anhydrous sodium sulfate and filtered. After removing the solvent in vacuo, the solid residue was purified by silica gel column chromatography using DCM / methyl tertiary butyl ether (MTBE) 95: 5 as the eluent, and further recrystallized from heptane / MTBE to obtain Of red crystals3 (4.2 g, m.p. 102 ° C).¹ H-NMR (CDCl₃ , 500 MHz): d (ppm): 6.54 (br. M., 1 H, H_Alkenes ), 6.24 (br. M., 1 H, H_Alkenes ), 6.00 (br. M., 1 H, H_Alkenes ), MS (EI⁺ ) m / z: C₁₂ H₂₀ NO₃ [M]⁺ Calculated value: 226.3; experimental value 226.1.Extra stabilizer As an additional stabilizer, it may be advantageous to use a compound selected from the structures S-1-3 or S-2-3, which has the following structure: Mixture example The following main mixtureH1 toH4 For making an example according to the invention:H1 : Nematic body - mixture H2 : Nematic body - mixture H3 : Nematic body - mixture H4 : Nematic body - mixture Comparative example A The mixture (A) was prepared by mixing the host mixture H1 with 0.05% by weight of the non-polymerizable stabilizer S-1-3. The mixture was studied in terms of voltage retention before and after the backlight load test.Mixture example 1 To the mixture (A) of the comparative example (A), a polymerizable additive RH-1 was added at a concentration of 0.01% by weight.Mixture example 2 To the mixture (A) of the comparative example (A), a polymerizable additive RH-2 was added at a concentration of 0.01% by weight.VHR Measure : Effect of polymerizable piperidine derivatives under backlight loading The test unit with (a) friction polyfluorene and (b) photo-aligned polyfluorene is filled with the medium of the previous example. For (a) and (b) (Tables 1 and 2), measure the voltage holding rate (VHR) of the test unit before and after the dense optical load (120 min). Illumination is equivalent to 500 hours of typical white CCFL backlight for displays. Table 1: Results of rubbing polyfluorene (OPTMER® AL16301, JSR Corp.): * BL = backlight load test; 120-hour accelerated LED-based backlight Table 2: Results of light alignment with polyimide: * BL = backlight load test; 120 h acceleration of LED-based backlightComparative example B The mixture (B) was prepared by mixing the host mixture H1 with 0.05% by weight of the non-polymerizable stabilizer S-2-3. The mixture was studied in terms of voltage retention before and after the backlight load test.Mixture example 3 To the mixture (B) of the comparative example (B), a polymerizable additive RH-1 was added at a concentration of 0.01% by weight.Mixture example 4 To the mixture (B) of the comparative example (B), a polymerizable additive RH-2 was added at a concentration of 0.01% by weight.VHR Measurement: Effect of polymerizable piperidine derivatives under backlight load The test units of (a) friction polyimide and (b) photo-aligned polyimide were filled with the media of the previous examples, and VHR was measured as above (Tables 3 and 4). Table 3: Results of rubbing polyfluorene (OPTMER® AL16301, JSR Corp.): * BL = backlight load test; 144 h accelerated LED-based backlight Table 4: Results of light alignment on polyimide: * BL = Backlight load test; 120 hours to accelerate LED-based backlighting By using polymerizable additives such as compounds of formula RH-1 or RH-2, avoid VHR drop after backlight load. The test unit filled with the mixture of Examples 1 to 4 showed that the VHR hardly decreased after backlight loading, while the comparative examples (Examples A and B) without any polymerizable additives showed a significant decrease in VHR.

Claims (13)

A liquid crystal medium having a nematic phase and a dielectric anisotropy (Δε) of 1.5 or more, characterized in that it contains at least one polymerizable compound of formula I or a polymer containing its polymerized form, P-Sp- ( A ² -Z ² -A ¹ ) _m1 -Z ¹ -TI wherein the groups are independent of each other and have the same or different meanings at each occurrence T is a group selected from the group consisting of R ^g H or a linear or branched alkyl or alkoxyalkyl group having 1 to 10 C atoms, or benzyl, R ^a , R ^b , R ^c , ^Rd having 1 to 10 C atoms Linear or branched alkyl, P vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane or epoxy, Sp spacer or single bond, A ¹ , a ² having 4 to 30 ring atoms an alicyclic group, a heterocyclic group, an aromatic group or heteroaromatic group, which may also contain fused rings and optionally substituted with one or more groups L, or R- (a ³ -Z ³ ) _m2 -substituted, and one of A ¹ and A ² may also represent a single bond, and A ³ has an alicyclic group, heterocyclic group, aromatic group or heteroaromatic group having 4 to 30 ring atoms Group, which may also contain fused rings and optionally substituted with one or more groups L, Z ¹ -O-, -S-, -CO-, -CO-O-, -O-CO-, -O- CO-O-, -OCH _2- , -CH ₂ O-, -SCH _2- , -CH ₂ S-, -CF ₂ O-, -OCF _2- , -CF ₂ S-, -SCF ₂ -,- (CH ₂ ) _n- , -CF ₂ CH _2- , -CH ₂ CF ₂ -,-(CF ₂ ) _n- , -CH = CH-, -CF = CF-, -CH = CF-, -CF = CH-, -CºC-, -CH = CH-CO-O-, -O-CO-CH = CH-, -CH ₂ -CH ₂ -CO-O-, -O-CO-CH ₂ -CH _2- , -CR ⁰⁰ R ⁰⁰⁰ -or single bond, the restriction is that if m1 is 0 and Sp is a single bond, then Z ¹ is a single bond, Z ² , Z ³ -O-, -S-, -CO- , -CO-O-, -O-CO-, -O-CO-O-, -OCH _2- , -CH ₂ O-, -SCH _2- , -CH ₂ S-, -CF ₂ O-,- OCF _2- , -CF ₂ S-, -SCF ₂ -,-(CH ₂ ) _n- , -CF ₂ CH _2- , -CH ₂ CF ₂ -,-(CF ₂ ) _n- , -CH = CH- , -CF = CF-, -CH = CF-, -CF = CH-, -CºC-, -CH = CH-CO-O-, -O-CO-CH = CH-, -CH ₂ -CH _2- CO-O-, -O-CO-CH ₂ -CH _2- , -CR ⁰⁰ R ⁰⁰⁰ -or a single bond, R ⁰⁰ , R ⁰⁰⁰ H or an alkyl group having 1 to 12 C atoms, R P-Sp- , H, F, Cl, CN or a linear, branched or cyclic alkyl group having 1 to 25 C atoms, where one or more non-adjacent CH ₂ -groups are optionally represented by -O-, -S -, -CO-, -CO-O-, -O-CO-, -O-CO-O- are replaced in such a way that O and / or S atoms are not directly connected to each other, and one or more of them are H atoms Each is optionally replaced by F, Cl, or P-Sp-, or R is a group selected from Formulas 1, 2, 3, and 4, L P-Sp-, F, Cl, CN, or has 1 to 25 C atoms the straight-chain, branched or cyclic alkyl group, wherein one or more non-adjacent CH ₂ - groups, as appropriate, Is replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that O atoms and / or S atoms are not directly connected to each other, and Wherein one or more H atoms are each optionally substituted by F, Cl or P-Sp-, or L is a group selected from Formulas 1, 2, 3 and 4, m1 0, 1, 2, 3 or 4, m2 0, 1, 2, 3, or 4, and n 1, 2, 3, or 4. As in the liquid crystal medium of claim 1, m1 is 0 or 1 in Formula I. The liquid crystal medium of claim 1, wherein the compounds of the formula I are selected from the group of compounds of the formula, where T is a group selected from or Wherein ^{R a, R b, R c} , R d is independently a linear or branched alkyl group having 1 to 10 C atoms. The liquid crystal medium of any one of claims 1 to 3, wherein it comprises one or more compounds selected from the group of compounds of formula II and compounds of formula III, Wherein 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, and an alkoxyalkyl group having 2 to 7 C atoms Or fluorinated alkenyl, L ²¹ and L ²² represent H or F, X ² represents 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, and m represents 0, 1, 2 or 3, and R ³ represents an alkyl group, alkoxy group, fluorinated alkyl group or fluorinated alkoxy group having 1 to 7 C atoms, alkenyl group, alkenyl group having 2 to 7 C atoms Oxy, alkoxyalkyl or fluorinated alkenyl, L ³¹ and L ³² , independently of each other, H or F, X ³ represents 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 Group, F, Cl, -OCF ₃ , -OCHF ₂ , -O-CH ₂ CF ₃ , -O-CH = CF ₂ , -O-CH = CH ₂ or -CF ₃ , Z ³ represents -CH ₂ CH ₂ -, -CF ₂ CF _2- , -COO-, trans-CH = CH-, trans-CF = CF-, -CH ₂ O- or a single bond, and n represents 0, 1, 2 or 3. The liquid crystal medium according to any one of claims 1 to 3, which comprises one or more dielectric neutral compounds selected from the group of formula IV and formula V: Wherein R ⁴¹ and R ⁴² each independently represent an alkyl group, alkoxy group, fluorinated alkyl group or fluorinated alkoxy group having 1 to 7 C atoms, an alkenyl group or alkenyl group having 2 to 7 C atoms Oxy, alkoxyalkyl or fluorinated alkenyl, Z ⁴¹ and Z ⁴² independently of each other and if Z ⁴¹ appears twice, these also independently represent each other -CH ₂ CH _2- , -COO-, trans-CH = CH-, trans-CF = CF-, -CH ₂ O-, -CF ₂ O-, -C≡C-, or a single bond, p represents 0, 1 or 2, R ⁵¹ and R ⁵² , and each independently represent an alkyl group having 1 to 7 C atoms, Alkoxy, fluorinated alkyl or fluorinated alkoxy, alkenyl with 2 to 7 C atoms, alkenyloxy, alkoxyalkyl or fluorinated alkenyl, Z ⁵¹ to Z ⁵³ each independently represent -CH ₂ -CH _2- , -CH ₂ -O-, -CH = CH-, -C≡C-, -COO-, or a single bond, and i and j are each other Independently represent 0 or 1. The liquid crystal medium of claim 5, wherein it comprises one or more compounds selected from the group consisting of formula S-1 and formula S-2 Where R ^S represents an alkyl, alkoxy, fluorinated alkyl, or fluorinated alkoxy group having 1 to 9 C atoms, or an alkenyl, alkenyloxy, or alkoxy group having 2 to 9 C atoms alkyl. The liquid crystal medium of any one of claims 1 to 3, wherein the total concentration of the compounds of the formula I in the medium as a whole is 0.001% or higher to 0.05% or lower. The liquid crystal medium of any one of claims 1 to 3, further comprising one or more compounds of formula IV-A Wherein R ⁴¹ represents an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkenyl group having 2 to 7 C atoms, and R ⁴² represents an unsubstituted alkyl group having 1 to 7 C atoms Alkyl, unsubstituted alkenyl having 2 to 7 C atoms or unsubstituted alkoxy having 1 to 6 C atoms. An electro-optical display or an electro-optical component, characterized in that it comprises a liquid crystal medium according to any one of claims 1 to 8. The display as claimed in claim 9, wherein it is based on the IPS mode or the FFS mode. A display as claimed in claim 9 or 10, which contains an active matrix addressing device. A use of a liquid crystal medium according to any one of claims 1 to 8 for use in an electro-optical display or an electro-optical module. A method for preparing a liquid crystal medium according to any one of claims 1 to 8, characterized in that one or more compounds of the formula I are mixed with one or more additional mesogen compounds and optionally one or more additives.