TW202302822A - Liquid-crystal medium - Google Patents

Abstract

The present invention relates to a liquid-crystal (LC) medium comprising a stabiliser, to its use for optical, electro-optical and electronic purposes, in particular in LC displays, especially in LC displays of the vertically aligned mode, to an LC display of the vertically aligned mode comprising the LC medium, and to a process of manufacturing the LC display.

Description

liquid crystal medium

The present invention relates to the use of liquid crystal (LC) media comprising stabilizers for optical, electro-optical and electrical purposes, in particular in LC displays, especially in LC displays in vertical alignment mode, including the vertical alignment of the LC media A mode LC display, and a method of manufacturing the LC display.

The popularity of 8K and gaming monitors has led to increased demand for LC display (LCD) panels with higher refresh rates and thus for LC media with faster response times. Many of these LCD panels are using a display mode in which the LC molecules are aligned substantially perpendicular to the electrode surface or slightly tilted relative to the electrode surface in the off state.

Thus, so-called VA (“Vertical Alignment”) displays are known, which have wide viewing angles and fast response times. The LC cell of a VA display contains a layer of an LC medium between two transparent electrodes, wherein the LC medium generally has a negative value of the dielectric anisotropy (Δε). In the off state, the molecules of the LC layer are aligned perpendicular to the electrode surface (vertical) or have a tilted vertical alignment. Upon application of a voltage to the two electrodes, a realignment of the LC molecules parallel to the electrode surfaces occurs.

Furthermore, so-called FFS ("Fringe Field Switching") displays have been reported (see especially, SH Jung et al., Jpn. J. Appl. Phys., Vol. 43 , No. 3, 2004, 1028), which on the same substrate Contains two electrodes, one of which is structured in a comb-like manner and the other unstructured. This results in a strong so-called "fringe field", ie a strong electric field close to the edge of the electrode and throughout the cell, an electric field with both a strong vertical component and also a strong horizontal component. FFS displays have a low viewing angle dependence of contrast. FFS displays typically contain an LC medium with positive dielectric anisotropy and an alignment layer, usually polyimide, which provides in-plane alignment with the molecules of the LC medium.

FFS displays can be operated as active matrix or passive matrix displays. In the case of active-matrix displays, individual pixels are usually addressed by integrated nonlinear active elements, such as, for example, transistors (e.g., thin-film transistors "TFTs"), while in the case of passive-matrix displays, individual pixels are usually addressed by Addressing is by a multi-pass method as known from the prior art.

Also known are so-called IPS (“In-Plane Switching”) displays, which contain an LC layer between two substrates with a planar orientation, where the two electrodes are arranged on only one of the two substrates and It preferably has an interlaced comb structure. When a voltage is applied to the electrodes, an electric field is generated between them with a significant component parallel to the LC layer. This causes a realignment of the LC molecules in the layer plane.

Furthermore, FFS displays have been disclosed (see S.H. Lee et al., Appl. Phys. Lett. 73(20), 1998, 2882-2883 and S.H. Lee et al., Liquid Crystals 39(9), 2012, 1141-1148), which Has a similar electrode design and layer thickness as the FFS display, but contains an LC medium with negative dielectric anisotropy instead of a layer of LC medium with positive dielectric anisotropy. LC media with negative dielectric anisotropy show a more favorable director orientation, which has less tilt and a more twisted orientation than LC media with positive dielectric anisotropy, as a result of which these displays have more High transmittance.

Furthermore, VA displays have been disclosed which use an alignment layer prepared by photo-alignment, also called ^UV2A mode (see, eg, Q. Tang et al., SID Symposium Digest of Technical Papers 2018, 414-417). These displays utilize alignment layers prepared from cross-linkable and photo-orientable monomers or prepolymers such as cinnamate chromophores obliquely illuminated with linearly polarized UV light. As a result, a cross-linked alignment layer is formed which induces uniaxial alignment with a pretilt angle of the LC molecules close to the surface of the LC molecules. By changing the direction of illumination, multi-domain configurations with different pretilt directions can be obtained.

However, the use of LC media with negative dielectric anisotropy in VA or FFS displays also has several disadvantages. For example, it has significantly lower reliability than LC media with positive dielectric anisotropy.

As used hereinafter, the term "reliability" means the performance of a display over time and with varying stress loads, such as causing display defects such as image sticking (area and line image sticking), non-uniformity, yogore, etc. and are familiar Performance qualities of light load, temperature, humidity or voltage known in the field of LC displays. As a standard parameter to classify reliability, the voltage hold ratio (VHR) value, which is a measure of maintaining a constant voltage in a test display, is commonly used. The higher the VHR value, the better the reliability of the medium.

The reduced reliability of LC media with negative dielectric anisotropy in VA or FFS displays can be explained by the interaction of the LC molecules with the polyimide of the alignment layer, as a consequence of which, self-alignment The layers extract ions, and indeed LC molecules with negative dielectric anisotropy therein extract such ions more efficiently.

This leads to new requirements for LC media to be used in VA or FFS displays. In particular, the LC media must exhibit high reliability and high VHR values after UV exposure. Further requirements are high specific resistance, large operating temperature range, short response time even at low temperatures, low threshold voltage, multiplicity of gray scales, high contrast and wide viewing angle, and reduced image sticking.

Therefore, in the displays known from the prior art, the undesired effect of so-called "image sticking" or "image burn-in" is often observed, wherein in LC displays the image produced by the temporary addressing of the individual pixels is even cut off. The electric field in these pixels remains visible after addressing other pixels.

On the one hand, this "image sticking" can occur if LC media with low VHR are used. The UV component of sunlight or backlight can cause undesired decomposition reactions of the LC molecules therein and thus lead to the generation of ionic or free radical impurities. In particular, these can build up at electrodes or alignment layers where they can reduce the effective applied voltage.

Another problem observed in the prior art is that LC media used in displays, including but not limited to VA and FFS displays, do often exhibit high viscosity and, consequently, high switching times. To reduce the viscosity and switching time of LC media, the addition of LC compounds with alkenyl groups has been suggested in the prior art. However, it has been observed that LC media containing alkenyl compounds generally show a decrease in reliability and stability, and a decrease in VHR, especially after exposure to UV radiation, but also visible light from the backlight of a display (which usually does not emit UV light).

。 To reduce the decrease in reliability and stability, it is recommended to use stabilizers such as, for example, HALS- ( Hindered Amine Light Stabilizer ) type compounds. A typical example is Tinuvin 770, a compound of the formula

.

However, these LC mixtures may still exhibit insufficient reliability during operation of the display, for example, after illumination with a typical CCFL- ( cold cathode fluorescent lamp ) backlight.

， 如DE 19539141 A1中所述。此等穩定劑可用於使LC混合物抵抗熱或氧氣之影響穩定，但是通常在光應力下不顯示優點。 A different class of compounds used to stabilize liquid crystals are antioxidants derived from phenols, such as, for example, compounds

, as described in DE 19539141 A1. These stabilizers can be used to stabilize LC mixtures against the influence of heat or oxygen, but generally show no benefit under light stress.

Because of the complex mode of action of different types of stabilizers and the minute effects of displays, where liquid crystals (complex mixtures of many different types of compounds themselves) interact with different types of species, including polyimides, it is important for the skilled person to choose the correct stabilizer Agents to identify the best combination of materials is also a challenging task. Therefore, there is still a great need for novel types of stabilizers with different properties in order to broaden the range of applicable materials.

It is therefore the object of the present invention to provide: a method for providing improved LC media for VA-, IPS- or FFS displays, which LC media do not exhibit the above-mentioned disadvantages or only to a small extent and have improved nature. A further object of the present invention is to provide a VHR value with good transmittance, high reliability, especially after backlight exposure, high specific resistance, large operating temperature range, short response time even at low temperatures, low threshold voltage, gray FFS display with high level multiplicity, high contrast and wide viewing angle, and reduced image sticking.

It was found that one or more of these objectives can be achieved by providing LC media as disclosed and claimed hereinafter.

In particular, the inventors of the present invention have found that the above objects can be achieved by using LC media in VA-, IPS or FFS displays comprising small amounts of stabilizers, which are compounds of formula I as described hereinafter. It has also been found that, when using LC media containing such stabilizers for FFS displays, the reliability and VHR values after backlight loading are surprisingly higher compared to LC media without stabilizers according to the invention.

Also, the use of LC media comprising stabilizers as described hereinafter allows to take advantage of the known advantages of alkenyl-containing LC media, such as reduced viscosity and faster switching times, and at the same time results in increased reliability and especially after backlight exposure. High VHR values.

其中該等個別基團彼此獨立地且每次出現時相同或不同地具有下列含義 P                     CW=CH-CO-O-， W                    H、F、Cl、CF ₃或具有1至5個C原子之烷基，較佳地H或CH ₃， Sp ¹、Sp ²、Sp ³視情況經P取代之間隔基團或單鍵， L                     F、Cl、-CN、P-Sp-或具有1至25個C原子之直鏈、分支鏈或環狀烷基，其中一或多個非鄰CH ₂-基團視情況以使得O-及/或S-原子彼此不直接連接之方式經-O-、-S-、-CO-、-CO-O-、-O-CO-、-O-CO-O-、CR ⁰=CR ⁰⁰-、-C≡C-、

、

、

、

、

或

置換，且其中一或多個H原子各視情況經P-Sp-、F或Cl置換， r、s                 0、1、2、3或4，較佳地0、1或2， 及另外包含一或多種式II化合物

其中該等個別基團彼此獨立地且每次出現時相同或不同地具有下列含義 R ¹、R ²具有1至25個C原子之直鏈、分支鏈或環狀烷基，其中一或多個非相鄰CH ₂-基團視情況以使得O-及/或S-原子彼此不直接連接之方式經-O-、-S-、-CO-、-CO-O-、-O-CO-、-O-CO-O-、CR ⁰=CR ⁰⁰-、-C≡C-、

、

、

、

、

或

置換，且其中一或多個H原子各視情況經F或Cl置換，較佳地具有1至6個C原子之烷基或烷氧基， A ¹、A ²選自下列式之基團

較佳地選自式A1、A2、A3、A4、A5、A6、A9及A10，極佳地選自式A1、A2、A3、A4、A5、A9及A10， Z ¹、Z ²-CH ₂CH ₂-、-CH=CH-、-CF ₂O-、-OCF ₂-、-CH ₂O-、-OCH ₂-、-CO-O-、-O-CO-、-C ₂F ₄-、-CF=CF-、-CH=CH-CH ₂O-或單鍵，較佳地單鍵， L ¹、L ²、L ³、L ⁴F、Cl、OCF ₃、CF ₃、CH ₃、CH ₂F或CHF ₂，較佳地F或Cl，極佳地F， Y                     H、F、Cl、CF ₃、CHF ₂或CH ₃，較佳地H或CH ₃，極佳地H， L ^CCH ₃或OCH ₃，較佳地CH ₃， a1                    1或2， a2                    0或1。 Accordingly, the present invention relates to an LC medium comprising one or more compounds of the formula I in a concentration of >0% by weight and ≤0.02% by weight

wherein the individual groups independently of one another and identically or differently at each occurrence have the following meanings P CW=CH-CO-O-, W H, F, Cl, CF ₃ or an alkyl group having 1 to 5 C atoms , preferably H or CH ₃ , Sp ¹ , Sp ² , Sp ³ are optionally substituted by P as a spacer or a single bond, LF, Cl, -CN, P-Sp- or one with 1 to 25 C atoms Straight-chain, branched or cyclic alkyl, wherein one or more non-ortho _CH2 -groups are optionally connected via -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, CR ⁰ =CR ⁰⁰ -, -C≡C-,

,

,

,

,

or

Replacement, and wherein one or more H atoms are replaced by P-Sp-, F or Cl as the case may be, r, s 0, 1, 2, 3 or 4, preferably 0, 1 or 2, and additionally comprising a or more compounds of formula II

wherein these individual groups independently of each other and each occurrence the same or differently have the following meanings R ¹ , R ² are linear, branched or cyclic alkyl groups having 1 to 25 C atoms, one or more of which Non-adjacent CH ₂ -groups optionally via -O-, -S-, -CO-, -CO-O-, -O-CO- , -O-CO-O-, CR ⁰ =CR ⁰⁰ -, -C≡C-,

,

,

,

,

or

Replacement, and wherein one or more H atoms are replaced by F or Cl as appropriate, preferably an alkyl or alkoxy group with 1 to 6 C atoms, A ¹ and A ² are selected from the groups of the following formula

Preferably selected from formulas A1, A2, A3, A4, A5, A6, A9 and A10, very preferably selected from formulas A1, A2, A3, A4, A5, A9 and A10, Z ¹ , Z ² -CH ₂ CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -CO-O-, -O-CO-, -C ₂ F ₄ - , -CF=CF-, -CH=CH-CH ₂ O- or a single bond, preferably a single bond, L ¹ , L ² , L ³ , L ⁴ F, Cl, OCF ₃ , CF ₃ , CH ₃ , CH ₂ F or CHF ₂ , preferably F or Cl, preferably F, Y H, F, Cl, CF ₃ , CHF ₂ or CH ₃ , preferably H or CH ₃ , preferably H, L ^C CH ₃ or OCH ₃ , preferably CH ₃ , a1 1 or 2, a2 0 or 1.

The present invention further relates to the use of an LC medium as described above and below in an LC display, preferably in an LC display in VA, IPS, FFS, UB-FFS or ^UV2A mode.

The LC medium has negative dielectric anisotropy.

Furthermore, the invention relates to a process for the preparation of LC media as described above and below, which comprises the mixing of one or more compounds of formula I with one or more compounds of formula II and optionally with further LC compounds and/or additives step.

Furthermore, the invention relates to an LC display as described above and below, preferably in VA, IPS, FFS, UB-FFS or ^UV2A mode, comprising an LC medium according to the invention.

Furthermore, the invention relates to a method of manufacturing an LC display as described above and hereinafter comprising the step of filling or otherwise providing an LC medium as described above and hereinafter between the substrates of the display.

It was surprisingly found that compounds of formula I, although carrying potentially reactive groups P, such as acrylates or methacrylates, which is the opposite of detrimental with regard to the reliability of LCs, are able to stabilize LC mixtures under light stress. It has also been found that if the concentration of the compound of formula I is kept low enough, the undesired generation of the pretilt angle of the LC medium, which is usually observed when using such compounds in VA mode displays and exposing them to UV radiation, can be suppressed. Tilt angle.

It was also found that, when using LC media containing compounds of the formula I for displays in VA or FFS mode, the reliability and VHR values after backlight loading are surprisingly better than LC media without the compounds of formula I according to the invention high.

Also, the use of LC media comprising compounds of formula I as described hereinafter allows to take advantage of the known advantages of alkenyl-containing LC media, such as reduced viscosity and faster switching times, and at the same time leads to increased reliability and especially after backlight exposure High VHR value.

Unless otherwise specified, the compounds of formula I are preferably selected from non-chiral compounds.

As used herein, the terms "active layer" and "switchable layer" mean a layer comprising one or more molecules with structural and optical anisotropy, such as, for example, LC molecules in electro-optic displays (e.g. LC displays), which Isomolecules change their orientation under external stimuli, such as electric or magnetic fields, resulting in a change in the transmission of polarized or unpolarized light by the layer.

As used herein, the terms "tilt" and "tilt angle" are understood to mean the alignment of the LC molecules of the LC medium relative to a cell surface in an LC display, preferably a PSA display, and it is understood that Include "pre-tilt" and "pre-tilt angle". The tilt angle here means the average angle (<90°) between the longitudinal molecular axis of the LC molecule (LC director) and the plane-parallel outer plate surface forming the LC cell. Here a low absolute value of the tilt angle (ie a large deviation from the 90° angle) corresponds to a large tilt. A suitable method for measuring the tilt angle is provided in the Examples. Unless otherwise specified, the tilt angle values disclosed above and below relate to this measurement method.

As used herein, the term "mesogen group" is known to those skilled in the art and described in the literature, and means that, due to its anisotropy of attractive and repulsive interactions, substantially contributes to the generation of low molecular weight or Groups of the liquid crystal (LC) phase of polymeric substances. A compound containing a mesogen group (mesogen compound) does not necessarily have to have an LC phase itself. Mesogen compounds may also exhibit LC phase behavior only after mixing with other compounds and/or after polymerization. Typical mesogen groups are, for example, rigid rod-like or discotic units. A summary of terms and definitions used in connection with mesogen or LC compounds is in Pure Appl. Chem. 2001, 73(5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004 , 116, 6340 Available in -6368.

As used herein, the term "spacer", hereinafter also referred to as "Sp", is known to those skilled in the art and is described in the literature, see, for example, Pure Appl. Chem. 2001, 73(5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004 , 116, 6340-6368. As used herein, the term "spacer group" or "spacer" means a flexible group in a polymerizable mesogen compound that connects the mesogen group and the polymerizable group(s), such as an extension alkyl.

表示反式-1,4-伸環己基環，及

表示1,4-伸苯基環。 above and below,

represents a trans-1,4-cyclohexylene ring, and

Represents a 1,4-phenylene ring.

中，在兩個環原子之間所示之單鍵可連接至苯環之任何游離位置。 Yu group

In , a single bond shown between two ring atoms can be attached to any free position of the benzene ring.

If, in the formulas shown above and below, the radicals R ^{1 to 12} , R ^Q , R or L represent alkyl and/or alkoxy, this may be straight-chain or branched. It is preferably a straight chain with 2, 3, 4, 5, 6 or 7 C atoms and thus preferably represents ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, Propoxy, butoxy, pentyloxy, hexyloxy or heptyloxy, in addition, methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, Pentadecyl, methoxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy or tetradecyloxy.

If in the formulas shown above and below, the groups R ^{1 to 13} , R ⁵¹ , R ⁵² , R ^Q , R, R ^2A , R ^2B , R ^IIIA , R ^1N , R ^2N , R ^B1 , R ^B2 , R ^CR1 , R ^CR2 , R or L represent an alkyl group and/or an alkoxy group, which may be a straight chain or a branched chain. It is preferably a straight chain with 2, 3, 4, 5, 6 or 7 C atoms and thus preferably represents ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, Propoxy, butoxy, pentyloxy, hexyloxy or heptyloxy, in addition, methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, Pentadecyl, methoxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy or tetradecyloxy.

If in the formulas shown above and below, the groups R ^{1 to 13} , R ⁵¹ , R ⁵² , R ^Q , R, R ^2A , R ^2B , R ^IIIA , R ^1N , R ^2N , R ^B1 , R ^B2 , R ^CR1 , R ^CR2 , R or L represent an alkyl group, wherein one or more CH ₂ groups are replaced by S, then this can be a straight chain or a branched chain. It is preferably straight-chain, has 1, 2, 3, 4, 5, 6 or 7 C atoms and thus preferably represents thiomethyl, thioethyl, thiopropyl, thiobutyl, thiopentyl , thiohexyl or thioheptyl.

Oxaalkyl preferably represents straight-chain 2-oxapropyl (=methoxymethyl), 2-oxabutyl (=ethoxymethyl) or 3-oxabutyl (=2- methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxa Heptyl, 2-, 3-, 4-, 5-, 6- or 7-oxa-octyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl , 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

If in the formulas shown above and below, the groups R ^{1 to 13} , R ⁵¹ , R ⁵² , R ^Q , R, R ^2A , R ^2B , R ^IIIA , R ^1N , R ^2N , R ^B1 , R ^B2 , R ^CR1 , R ^CR2 , R or L represent alkoxy or oxaalkyl, which may also contain one or more additional oxygen atoms, as long as the oxygen atoms are not directly bonded to each other.

-S ¹-F、-O-S ¹-F、-O-S ₁-O-S ₂組成之群，其中S ¹為C _1-12-伸烷基或C _2-12-伸烷基且S ²為H、C _1-12-烷基或C _2-12-烯基，及極佳地選自由

-OCH ₂OCH ₃、-O(CH ₂) ₂OCH ₃、-O(CH ₂) ₃OCH ₃、-O(CH ₂) ₄OCH ₃、-O(CH ₂) ₂F、-O(CH ₂) ₃F及-O(CH ₂) ₄F組成之群。 In another preferred embodiment, R ^{1 to 13} , R ⁵¹ , R ⁵² , R ^Q , R, R ^2A , R ^2B , R ^IIIA , R ^1N , R ^2N , R ^B1 , R ^B2 , R ^CR1 , R One or more of ^CR2 , R or L are selected from

The group consisting of -S ¹ -F, -OS ¹ -F, -OS ₁ -OS ₂ , wherein S ¹ is C _1-12 -alkylene or C _2-12 -alkylene and S ² is H, C _1-12 -alkyl or C _2-12 -alkenyl, and preferably selected from

-OCH ₂ OCH ₃ , -O(CH ₂ ) ₂ OCH ₃ , -O(CH ₂ ) ₃ OCH ₃ , -O(CH ₂ ) ₄ OCH ₃ , -O(CH ₂ ) ₂ F, -O(CH ₂ ) ₃ F and -O(CH ₂ ) ₄ F.

If in the formulas shown above and below, the groups R ^{1 to 13} , R ⁵¹ , R ⁵² , R ^Q , R, R ^2A , R ^2B , R ^IIIA , R ^1N , R ^2N , R ^B1 , R ^B2 , R ^CR1 , R ^CR2 , R or L represent an alkyl group, where one CH ₂ group has been replaced by -CH=CH-, then this can be a straight chain or a branched chain. It is preferably linear and has 2 to 10 C atoms. Thus, it specifically denotes vinyl, prop-1- or -2-enyl, but-1-, -2- or -3-enyl, pent-1-, -2-, -3- or - 4-enyl, hex-1-, -2-, -3-, -4- or -5-enyl, hept-1-, -2-, -3-, -4-, -5- or - 6-enyl, oct-1-, -2-, -3-, -4-, -5-, -6- or -7-enyl, nonan-1-, -2-, -3-, - 4-, -5-, -6-, -7- or -8-enyl, dec-1-, -2-, -3-, -4-, -5-, -6-, -7-, -8- or -9-alkenyl.

If in the formulas shown above and below, the groups R ^{1 to 13} , R ⁵¹ , R ⁵² , R ^Q , R, R ^2A , R ^2B , R ^IIIA , R ^1N , R ^2N , R ^B1 , R ^B2 , R ^CR1 , R ^CR2 , R or L represent an alkyl or alkenyl group which is at least monosubstituted with a halogen, and this group is preferably a straight chain, and the halogen is preferably F or Cl. In case of multiple substitution, halogen is preferably F. The resulting groups also contain perfluorinated groups. In the case of monosubstitution, the fluorine or chlorine substituent can be in any desired position, but is preferably in the ω position.

Halogen is preferably F or Cl, most preferably F.

The group -CR ⁰ =CR ⁰⁰ - is preferably -CH=CH-.

。 -OC-, -CO-, -C(=O)- and -C(O)- represent carbonyl groups, namely

.

Preferred substituents L are, for example, F, Cl, Br, I, -CN, -NO ₂ , -NCO, -NCS, -OCN, -SCN, -C(=O)N(R ^x ) ₂ , - C(=O)Y ¹ , -C(=O)R ^x , -N(R ^x ) ₂ , straight or branched chain alkyl, alkoxy, alkylcarbonyl, alkyl each having 1 to 25 C atoms Oxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, wherein one or more H atoms are optionally replaced by F or Cl, optionally substituted silicon groups with 1 to 20 Si atoms, or 6 to 25 A, preferably optionally substituted aryl groups of 6 to 15 C atoms, wherein R ^x represents H, F, Cl, CN or a linear, branched or cyclic alkyl group having 1 to 25 C atoms , wherein one or more non-adjacent CH ₂ -groups are optionally connected via -O-, -S-, -CO-, -CO-O- in such a way that the O- and/or S-atoms are not directly linked to each other , -O-CO-, -O-CO-O-, and wherein one or more H atoms are each optionally replaced by F, Cl, P- or P-Sp-, and Y ¹ represents halogen.

Particularly preferred substituents L are, for example, F, Cl, CN, NO ₂ , CH ₃ , C ₂ H ₅ , OCH ₃ , OC ₂ H ₅ , COCH ₃ , COC ₂ H ₅ , COOCH ₃ , COOC ₂ H ₅ , CF ₃ , OCF ₃ , OCHF ₂ , OC ₂ F ₅ , and phenyl.

較佳地為

、

、

或

，其中L具有以上指定之含義中之一者。

preferably

,

,

or

, wherein L has one of the meanings specified above.

In formula I and its sub-formula compounds, the group P is preferably selected from the group consisting of acrylate, methacrylate, fluoroacrylate and chloroacrylate, more preferably selected from acrylate and methacrylate, Optimally P represents methacrylate.

Very preferably, all radicals P in the compounds of formula I and its subformulas have the same meaning, and very preferably represent acrylate or methacrylate, most preferably methacrylate.

If one of the spacer groups Sp ^{1 to 3} is different from a single bond, it is preferably of the formula Sp"-X", so that the corresponding group P-Sp- corresponds to the formula P-Sp"-X"-, where Sp" denotes a straight-chain or branched chain alkylene group having 1 to 20, preferably 1 to 12 C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN and in addition, wherein One or more non-adjacent _CH2 groups can each be independently connected to each other via -O-, -S-, -NH-, -N(R ⁰ )- , -Si(R ⁰ R ⁰⁰ )-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -S-CO-, -CO-S-, -N( R ⁰⁰ )-CO-O-, -O-CO-N(R ⁰ )-, -N(R ⁰ )-CO-N(R ⁰⁰ )-, -CH=CH- or -C≡C- substitution, X" means -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CO-N(R ⁰ )-, -N(R ⁰ )-CO-, -N(R ⁰ )-CO-N(R ⁰⁰ )-, -OCH ₂ -, -CH ₂ O-, -SCH ₂ -, -CH ₂ S-, -CF ₂ O-, - OCF ₂ -, -CF ₂ S-, -SCF ₂ -, -CF ₂ CH ₂ -, -CH ₂ CF ₂ -, -CF ₂ CF ₂ -, -CH=N-, -N=CH-, -N =N-, -CH=CR ⁰ -, -CY ² =CY ³ -, -C≡C-, -CH=CH-CO-O-, -O-CO-CH=CH- or single bond, R ⁰ and R ⁰⁰ each independently represent H or an alkyl group having 1 to 20 C atoms, and Y ² and Y ³ each independently represent H, F, Cl or CN.

X" is preferably -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR ⁰ -, -NR ⁰ -CO-, -NR ⁰ - CO-NR ⁰⁰ - or single bond.

Typical spacer groups Sp ^{1 to 3} and -Sp"-X"- are for example -(CH ₂ ) _p1 -, -(CH ₂ ) _p1 -O-, -(CH ₂ ) _p1 -O-CO-, -(CH ₂ ) _p1 -CO-O-, -(CH ₂ ) _p1 -O-CO-O-, -(CH ₂ CH ₂ O) _q1 -CH ₂ CH ₂ -, -CH ₂ CH ₂ -S- CH ₂ CH ₂ -, -CH ₂ CH ₂ -NH-CH ₂ CH ₂ -or -(SiR ⁰ R ⁰⁰ -O) _p1 -, wherein p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R ⁰ and R ⁰⁰ have the meanings specified above.

Particularly preferred groups Sp ^{1 to 3} and -Sp"-X"- are -(CH ₂ ) _p1 -, -(CH ₂ ) _p1 -O-, -(CH ₂ ) _p1 -O-CO-, -(CH ₂ ) _p1 -CO-O-, -(CH ₂ ) _p1 -O-CO-O-, wherein p1 and q1 have the meanings specified above.

Particularly preferred groups Sp" in each case of a straight chain are ethylenyl, propylenyl, butylene, pentyl, hexyl, heptyl, octyl, nonyl, decyl, decyl, Undecyl, dodecyl, octadecyl, ethyloxyethyl, methyleneoxybutyl, ethylthioethyl, ethyl-N-methylimino- Ethylene, 1-methylalkylene, vinylene, propenyl and butenyl.

Preferred compounds of formula I and subformulae thereof are those wherein at least one of the groups Sp ^{1 to 3} is a single bond. Further preferred compounds of formula I and subformulae thereof are those in which at least one of the radicals Sp ^{1 to 3} is different from a single bond.

Excellent is the compound of formula I and sub-formulae thereof, wherein Sp ^{1 to 3} are selected from single bond, -(CH ₂ ) _p1 -, -O-(CH ₂ ) _p1 -, -O-CO-(CH ₂ ) _p1 and The group consisting of -CO-O-(CH ₂ ) _p1 , wherein p1 is 2, 3, 4, 5 or 6, and if Sp is -O-(CH ₂ ) _p1 -, -O-CO-(CH ₂ ) _p1 or -CO-O-(CH ₂ ) _p1 , the O-atom or CO-group is each attached to the benzene ring.

Further preferred compounds of formula I and its subformulas as described above and below are selected from the following preferred embodiments, including any combination thereof: - all groups P have the same meaning and very preferably represent acrylate or methacrylic acid Esters, best and methacrylates, - all Sp ^{1 to 3} are single bonds, - all Sp ^{1 to 3} are different from single bonds, - one of Sp ^{1 to 3} is single bonds and the other two are different from single bonds key, - one of Sp ^{1 to 3} is different from a single bond and the other two each represent a single bond, - Sp ¹ is a single bond and one or both of Sp ² and Sp ³ , preferably Sp ² and Both Sp ³ are different from a single bond, - when different from a single bond, Sp ^{1 to 3} are selected from -(CH ₂ ) ₂ -, -(CH ₂ ) ₃ -, -(CH ₂ ) ₄ -, -O -(CH ₂ ) ₂ -, -O-(CH ₂ ) ₃ -, -O-CO-(CH ₂ ) ₂ and -CO-O-(CH) ₂ -, wherein the O atom or CO group group is attached to the benzene ring, -at least one of the groups Sp ^{1 to 3} is different from a single bond and is selected from -(CH ₂ ) ₂ -, -(CH ₂ ) ₃ -, -(CH ₂ ) ₄ -, A group consisting of -O-(CH ₂ ) ₂ -, -O-(CH ₂ ) ₃ -, -O-CO-(CH ₂ ) ₂ and -CO-O-(CH) ₂ -, wherein the O atom or The CO group is attached to the benzene ring, - when different from a single bond, Sp ^{1 to 3} represents an alkylene group with 2 to 6 C atoms, - r and s are independently 0, 1 or 2, and r and The sum of s is 0, 1 or 2, - r=s=0 or r=0 and s=1 or r=1 and s=0 or r=s=1, - L represents F, Cl, CN or OCH ₃ , excellently F or OCH ₃ .

其中P及L具有式I之含義或上文及下文中給定之較佳含義中之一者，且Sp’具有如式I給定之Sp之含義中之一者，或上文及下文中給定之較佳含義中之一者，其不同於單鍵。 Another preferred compound of formula I is selected from the following subformulas:

wherein P and L have the meaning of formula I or one of the preferred meanings given above and below, and Sp' has one of the meanings of Sp as given in formula I, or one of the meanings given above and below One of the preferred meanings, which is different from a single bond.

Sp' in formulas I1 to I8 is preferably selected from -(CH ₂ ) ₂ -, -(CH ₂ ) ₃ -, -(CH ₂ ) ₄ -, -O-(CH ₂ ) ₂ -, -O- The group consisting of (CH ₂ ) ₃ -, -O-CO-(CH ₂ ) ₂ and -CO-O-(CH) ₂ -, wherein the O atom or CO group is attached to a benzene ring.

L in formulas I1 to I8 preferably represents F, Cl, CN or OCH ₃ , very preferably F or OCH ₃ .

Excellent formula I compounds are selected from the following subformulas:

Also preferred are compounds of formula I1a to I6a, wherein one, two or three of the methacrylate groups are replaced by acrylate groups.

The concentration of the compounds of formula I and its sub-formulas in the LC medium is preferably 0.001 to 0.02%, very preferably 0.002 to 0.015%, most preferably 0.005 to 0.015%.

In another preferred embodiment, the concentration of the compound of formula I and its sub-formulas in the LC medium is 10 to 250 ppm, preferably 20 to 200 ppm, most preferably 50 to 150 ppm.

Compounds of formula I can be prepared analogously to methods known to the person skilled in the art and described in standard works of organic chemistry, such as, for example, Houben-Weyl, Methoden der organischen Chemie [Methods in Organic Chemistry], Thieme-Verlag, Stuttgart.

For example, acrylates or methacrylates can be prepared by reacting alcohols with acid derivatives (such as For example (meth)acrylic chloride or (meth)acrylic anhydride) esterification preparation. Alternatively, esters can be prepared by using dicyclohexylcarbodiimide (DCC), N- (3-dimethylaminopropyl) -N' -ethylcarbodiimide in the presence of a dehydrating agent, for example, according to Steglich (EDC) or N- (3-dimethylaminopropyl) -N' -ethylcarbodiimide hydrochloride and DMAP, prepared by esterification of alcohol and (meth)acrylic acid.

In addition to the above-mentioned compounds of formula I, the LC medium used in the LC display according to the invention comprises an LC mixture ("host mixture") containing one or more, preferably two or more LC compounds, of which At least one of them is a compound of formula II.

A particularly preferred embodiment of this LC medium is shown below.

其中 R ^2A及R ^2B各彼此獨立地表示H、具有至多15個C原子之烷基或烯基，其未經取代、經CN或CF ₃單取代或至少經鹵素單取代，此外，其中此等基團中之一或多個CH ₂基團可以使得O原子彼此不直接連接之方式經-O-、-S-、

、

、

、

、

、

、-C≡C-、-CF ₂O-、-OCF ₂-、-OC-O-或-O-CO-置換， L ¹至L ⁴各彼此獨立地表示F、Cl、CF ₃或CHF ₂， Y                表示H、F、Cl、CF ₃、CHF ₂或CH ₃，較佳地H或CH ₃，特別佳地H， Z ²、Z ^2B及Z ^2D各彼此獨立地表示單鍵、-CH ₂CH ₂-、-CH=CH-、-CF ₂O-、-OCF ₂-、-CH ₂O-、-OCH ₂-、-COO-、-OCO-、-C ₂F ₄-、-CF=CF-、-CH=CHCH ₂O-， p                表示0、1或2，且 q                每次出現時，相同或不同地表示0或1。 Preferably, the LC medium contains one or more compounds of formula II selected from the group consisting of compounds of formula IIA, IIB, IIC and IID

wherein R ^2A and R ^2B each independently represent H, an alkyl or alkenyl group having up to 15 C atoms, which is unsubstituted, monosubstituted with CN or CF ₃ or at least monosubstituted with halogen, furthermore, wherein One or more of the _CH2 groups in the group can be connected via -O-, -S-,

,

,

,

,

,

, -C≡C-, -CF ₂ O-, -OCF ₂ -, -OC-O- or -O-CO- replacement, L ¹ to L ⁴ each independently represent F, Cl, CF ₃ or CHF ₂ , Y represents H, F, Cl, CF ₃ , CHF ₂ or CH ₃ , preferably H or CH ₃ , especially preferably H, Z ² , Z ^2B and Z ^2D each independently represent a single bond, -CH ₂ CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO-, -C ₂ F ₄ -, -CF= CF-, -CH=CHCH ₂ O-, p represents 0, 1 or 2, and q represents 0 or 1 identically or differently each time it appears.

Preferred compounds of formula IIA, IIB, IIC and IID are those, wherein R ^2B represents an alkyl or alkoxy group having up to 15 C atoms, and very preferably represents (O)C _v H _2v+1 , wherein ( O) is an oxygen atom or a single bond and v is 1, 2, 3, 4, 5 or 6.

， 其中S ¹為C _1-5-伸烷基或C _2-5-伸烯基且S ²為H、C _1-7-烷基或C _2-7-烯基，及極佳地選自由以下組成之群：

。 Further preferred compounds of formulas IIA, IIB, IIC and IID are those wherein R ^2A or R ^2B represents or contains cycloalkyl or cycloalkoxy, preferably selected from the group consisting of:

, wherein S ¹ is C _1-5 -alkylene or C _2-5 -alkenyl and S ² is H, C _1-7 -alkyl or C _2-7 -alkenyl, and is preferably selected from A group consisting of:

.

其中指數a表示1或2，「alkyl」及「alkyl*」各彼此獨立地表示具有1至6個C原子之直鏈烷基，「alkenyl」表示具有2至6個C原子之直鏈烯基，且(O)表示氧原子或單鍵。「alkenyl」較佳地表示CH ₂=CH-、CH ₂=CHCH ₂CH ₂-、CH ₃-CH=CH-、CH ₃-CH ₂-CH=CH-、CH ₃-(CH ₂) ₂-CH=CH-、CH ₃-(CH ₂) ₃-CH=CH-或CH ₃-CH=CH-(CH ₂) ₂-。 In a preferred embodiment, the LC medium comprises one or more compounds of formula IIA selected from the group consisting of formulas IIA-1 to IIA-76

where the index a represents 1 or 2, "alkyl" and "alkyl*" each independently represent a straight-chain alkyl group having 1 to 6 C atoms, and "alkenyl" represents a straight-chain alkenyl group having 2 to 6 C atoms , and (O) represents an oxygen atom or a single bond. "Alkenyl" preferably represents CH ₂ =CH-, CH ₂ =CHCH ₂ CH ₂ -, CH ₃ -CH=CH-, CH ₃ -CH ₂ -CH=CH-, CH ₃ -(CH ₂ ) ₂ - CH=CH-, CH ₃ -(CH ₂ ) ₃ -CH=CH- or CH ₃ -CH=CH-(CH ₂ ) ₂ -.

Particularly preferred LC media according to the invention comprise one or more compounds selected from the group consisting of formulas IIA-2, IIA-8, IIA-10, IIA-16, II-18, IIA-40, IIA-41, IIA-42 and IIA-43 Compounds that make up a group.

其中「alkyl」、「alkyl*」、「alkenyl」及(O)具有以上給定之含義。 In another preferred embodiment, the LC medium comprises one or more compounds of formula IIB selected from the group consisting of formulas IIB-1 to IIB-26

wherein "alkyl", "alkyl*", "alkenyl" and (O) have the meanings given above.

Particularly preferred LC media according to the invention comprise one or more compounds selected from the group consisting of formulas IIB-2, IIB-10 and IIB-16.

其中「alkyl」及「alkyl*」及(O)具有以上給定之含義。 In another preferred embodiment, the LC medium comprises one or more compounds of formula IIC selected from formula IIC-1

wherein "alkyl" and "alkyl*" and (O) have the meanings given above.

其中「alkyl」、「alkyl*」、「alkenyl」及(O)具有以上給定之含義。 In another preferred embodiment, the LC medium comprises one or more compounds of formula IID selected from the group consisting of formulas IID-1 to IID-10

wherein "alkyl", "alkyl*", "alkenyl" and (O) have the meanings given above.

Particularly preferred LC media according to the invention comprise one or more compounds of formula IID-4.

The proportion of compounds of the formulas IIA and/or IIB in the mixture as a whole is preferably at least 20% by weight.

其中 R ¹¹及R ¹²各彼此獨立地表示H、具有1至15個C原子之烷基或烷氧基，其中此等基團中之一或多個CH ₂基團可各彼此獨立地以使得O原子彼此不直接連接之方式經

、

、

、

、

、

、-O-、-S-、-C≡C-、-CF ₂O-、-OCF ₂-、-CH=CH-、-OC-O-或-O-CO-置換，且此外，其中一或多個H原子可經鹵素置換， A ³每次出現時，彼此獨立地表示 a) 1,4-伸環己烯基或1,4-伸環己基，其中一個或兩個非相鄰CH ₂基團可經-O-或-S-置換， b) 1,4-伸苯基，其中一個或兩個CH基團可經N置換，或 c)選自由以下組成之群之基團：螺[3.3]庚烷-2,6-二基、1,4-雙環[2.2.2]伸辛基、萘-2,6-二基、十氫萘-2,6-二基、1,2,3,4-四氫萘-2,6-二基、菲-2,7-二基及茀-2,7-二基， 其中該等基團a)、b)及c)可經鹵素原子單取代或多取代， n           表示0、1或2，較佳地0或1， Z ¹每次出現時，彼此獨立地表示-CO-O-、-O-CO-、-CF ₂O-、-OCF ₂-、-CH ₂O-、-OCH ₂-、-CH ₂-、-CH ₂CH ₂-、-(CH ₂) ₄-、-CH=CH-CH ₂O-、-C ₂F ₄-、-CH ₂CF ₂-、-CF ₂CH ₂-、-CF=CF-、-CH=CF-、-CF=CH-、-CH=CH-、-C≡C-或單鍵，且 L ¹¹及L ¹²各彼此獨立地表示F、Cl、CF ₃或CHF ₂，較佳地H或F，最佳地F，且 W          表示O或S。 In another preferred embodiment, the LC medium comprises one or more compounds of formula III

wherein R ¹¹ and R ¹² each independently represent H, an alkyl or alkoxy group having 1 to 15 C atoms, wherein one or more _CH groups in these groups may each be independently such that The O atoms are not directly connected to each other by means of

,

,

,

,

,

, -O-, -S-, -C≡C-, -CF ₂ O-, -OCF ₂ -, -CH=CH-, -OC-O- or -O-CO-, and in addition, one of or multiple H atoms may be replaced by halogen, each occurrence of A ³ independently of each other represents a) 1,4-cyclohexenyl or 1,4-cyclohexylene, wherein one or two non-adjacent CH ₂ groups may be replaced by -O- or -S-, b) a 1,4-phenylene group in which one or both CH groups may be replaced by N, or c) a group selected from the group consisting of: Spiro[3.3]heptane-2,6-diyl, 1,4-bicyclo[2.2.2]octyl, naphthalene-2,6-diyl, decalin-2,6-diyl, 1, 2,3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl and fluorene-2,7-diyl, wherein these groups a), b) and c) can be obtained by Halogen atoms are monosubstituted or multisubstituted, n represents 0, 1 or 2, preferably 0 or 1, and Z ¹ each time independently represents -CO-O-, -O-CO-, -CF ₂ O -, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -CH ₂ -, -CH ₂ CH ₂ -, -(CH ₂ ) ₄ -, -CH=CH-CH ₂ O-, -C ₂ F ₄ -, -CH ₂ CF ₂ -, -CF ₂ CH ₂ -, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C- or bond, and L ¹¹ and L ¹² each independently represent F, Cl, CF ₃ or CHF ₂ , preferably H or F, most preferably F, and W represents O or S.

其中該等出現之基團具有與在上式III下給定相同之含義及較佳地 R ¹¹及R ¹²各彼此獨立地為具有至多15個C原子之烷基、烯基或烷氧基，更佳地其中之一者或二者表示烷氧基且 L ¹¹及L ¹²各較佳地表示F。 In a preferred embodiment of the present invention, the LC medium comprises one or more compounds of formula III-1 and/or III-2

wherein the groups present have the same meanings as given under formula III above and preferably R ^{and R} are each independently of each other an alkyl, alkenyl or alkoxy group having up to 15 C atoms, More preferably one or both of them represent alkoxy and each of L ¹¹ and L ¹² preferably represents F.

， 其中「alkyl」及「alkyl*」各彼此獨立地表示具有1至6個C原子之直鏈烷基，「alkenyl」及「alkenyl*」各彼此獨立地表示具有2至6個C原子之直鏈烯基，「alkoxy」及「alkoxy*」各彼此獨立地表示具有1至6個C原子之直鏈烷氧基，且L ¹¹及L ¹²各彼此獨立地表示F或Cl，較佳地均為F。 In another preferred embodiment, the LC medium comprises one or more compounds of formula III-1 selected from the group consisting of formula III-1-1 to III-1-10, preferably formula III-1-6

, wherein "alkyl" and "alkyl*" each independently represent a straight-chain alkyl group having 1 to 6 C atoms, and "alkenyl" and "alkenyl*" each independently represent a straight-chain alkyl group having 2 to 6 C atoms. Alkenyl, "alkoxy" and "alkoxy*" each independently represent a straight-chain alkoxy group having 1 to 6 C atoms, and L ¹¹ and L ¹² each independently represent F or Cl, preferably both for F.

， 其中「alkyl」及「alkyl*」各彼此獨立地表示具有1至6個C原子之直鏈烷基，「alkenyl」及「alkenyl*」各彼此獨立地表示具有2至6個C原子之直鏈烯基，「alkoxy」及「alkoxy*」各彼此獨立地表示具有1至6個C原子之直鏈烷氧基，且L ¹¹及L ¹²各彼此獨立地表示F或Cl，較佳地均為F。 In another preferred embodiment, the LC medium comprises one or more compounds of formula III-2 selected from the group consisting of formula III-2-1 to III-2-10, preferably formula III-2-6

, wherein "alkyl" and "alkyl*" each independently represent a straight-chain alkyl group having 1 to 6 C atoms, and "alkenyl" and "alkenyl*" each independently represent a straight-chain alkyl group having 2 to 6 C atoms. Alkenyl, "alkoxy" and "alkoxy*" each independently represent a straight-chain alkoxy group having 1 to 6 C atoms, and L ¹¹ and L ¹² each independently represent F or Cl, preferably both for F.

In an excellent embodiment, the LC medium comprises one or more compounds selected from the group consisting of

其中L ¹¹及L ¹²具有與在式III下給定相同之含義，(O)表示O或單鍵， R ^IIIA表示具有至多7個C原子之烷基或烯基或基團Cy-C _mH _2m+1-， m及n     相同或不同地為0、1、2、3、4、5或6，較佳地1、2或3，極佳地1，且 Cy        表示具有3、4或5個環原子之環脂族基團，其視情況經各具有至多3個C原子之烷基或烯基或經鹵素或CN取代，及較佳地表示環丙基、環丁基或環戊基。 In another preferred embodiment of the present invention, the LC medium comprises one or more compounds of formula IIIA-1 and/or IIIA-2

wherein L ¹¹ and L ¹² have the same meanings as given under formula III, (O) represents O or a single bond, R ^IIIA represents an alkyl or alkenyl group or group Cy-C _m H having up to 7 C atoms _2m+1- , m and n are identically or differently 0, 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, and extremely preferably 1, and Cy represents having 3, 4 or 5 Cycloaliphatic group of 2 ring atoms, which is optionally substituted by alkyl or alkenyl groups each having up to 3 C atoms or by halogen or CN, and preferably represents cyclopropyl, cyclobutyl or cyclopentyl .

Instead of or in addition to, preferably in addition to, the compound of formula III, the compound of formula IIIA-1 and/or IIIA-2 is contained in the LC medium.

其中「alkoxy」表示具有1至6個C原子之直鏈烷氧基，及較佳地表示正丙氧基、正丁氧基、正戊氧基或正己氧基。 Excellent compounds of formula IIIA-1 and IIIA-2 are the following:

Wherein "alkoxy" represents a straight-chain alkoxy group having 1 to 6 C atoms, and preferably represents n-propoxy, n-butoxy, n-pentoxy or n-hexyloxy.

其中 R ¹¹、R ¹²相同或不同地表示H、具有1至15個C原子之烷基或烷氧基，其中此等基團中之一或多個CH ₂基團彼此獨立地視情況以使得O原子彼此不直接連接之方式經-C≡C-、-CF ₂O-、-OCF ₂-、-CH=CH-、

、

、

、

、

、

、-O-、-S-、-OC-O-或-O-CO-置換，且此外，其中一或多個H原子可經鹵素取代。 In a preferred embodiment of the present invention, the LC medium comprises one or more compounds of formula III-3

wherein R ¹¹ and R ¹² identically or differently represent H, an alkyl or alkoxy group having 1 to 15 C atoms, wherein one or more CH ₂ groups in these groups are independently of each other such that The O atoms are not directly connected to each other through -C≡C-, -CF ₂ O-, -OCF ₂ -, -CH=CH-,

,

,

,

,

,

, -O-, -S-, -OC-O-, or -O-CO-, and in addition, one or more of the H atoms may be substituted by halogen.

其中R ¹²表示具有1至7個C原子之烷基，較佳地乙基、正丙基、正丁基、正戊基或正己基，或或者環丙基甲基、環丁基甲基或環戊基甲基。 Compounds of formula III-3 are preferably selected from the group consisting of formulas III-3-1 to III-3-11:

wherein R represents an ^alkyl group having 1 to 7 C atoms, preferably ethyl, n-propyl, n-butyl, n-pentyl or n-hexyl, or cyclopropylmethyl, cyclobutylmethyl or cyclopentyl base methyl.

其中該等參數具有以上給定之含義，R ¹¹較佳地表示直鏈烷基且R ¹²較佳地表示烷氧基，其各具有1至7個C原子。 In another preferred embodiment of the present invention, the LC medium comprises one or more compounds of formula III-4 to III-6, preferably formula III-5

Where these parameters have the meanings given above, R ¹¹ preferably represents straight-chain alkyl and R ¹² preferably represents alkoxy, each having 1 to 7 C atoms.

其中該等參數具有以上給定之含義，R ¹¹較佳地表示直鏈烷基且R ¹²較佳地表示烷氧基，其各具有1至7個C原子。 In another preferred embodiment, the LC medium comprises one or more compounds of formula III selected from the group consisting of formula III-7 to III-9, preferably formula III-8

Where these parameters have the meanings given above, R ¹¹ preferably represents straight-chain alkyl and R ¹² preferably represents alkoxy, each having 1 to 7 C atoms.

其中 R ⁴¹表示具有1至7個C原子之未經取代之烷基或具有2至7個C原子之未經取代之烯基，較佳地正烷基，特別佳地具有2、3、4或5個C原子，且 R ⁴²表示具有1至7個C原子之未經取代之烷基或具有1至6個C原子之未經取代之烷氧基，二者較佳地具有2至5個C原子，具有2至7個C原子，較佳地具有2、3或4個C原子之未經取代之烯基，更佳地乙烯基或1-丙烯基及特定言之乙烯基。 In a preferred embodiment, the medium comprises one or more compounds of formula IV

Wherein ^R represents unsubstituted alkyl with 1 to 7 C atoms or unsubstituted alkenyl with 2 to 7 C atoms, preferably n-alkyl, particularly preferably with 2, 3, 4 or 5 C atoms, and R ⁴² represents an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkoxy group having 1 to 6 C atoms, both preferably having 2 to 5 C atoms, unsubstituted alkenyl having 2 to 7 C atoms, preferably 2, 3 or 4 C atoms, more preferably vinyl or 1-propenyl and in particular vinyl.

其中 「alkyl」及「alkyl*」彼此獨立地表示具有1至7個C原子，較佳地具有2至5個C原子之烷基， 「alkenyl」             表示具有2至5個C原子，較佳地具有2至4個C原子，特別佳地2個C原子之烯基， 「alkenyl*」           表示具有2至5個C原子，較佳地具有2至4個C原子，特別佳地具有2至3個C原子之烯基，且 「alkoxy」              表示具有1至5個C原子，較佳地具有2至4個C原子之烷氧基。 Compounds of formula IV are preferably selected from the group consisting of formulas IV-1 to IV-6,

Wherein "alkyl" and "alkyl*" independently represent an alkyl group having 1 to 7 C atoms, preferably having 2 to 5 C atoms, and "alkenyl" represents having 2 to 5 C atoms, preferably Alkenyl having 2 to 4 C atoms, particularly preferably 2 C atoms, "alkenyl*" means having 2 to 5 C atoms, preferably 2 to 4 C atoms, particularly preferably 2 to 3 Alkenyl having 1 to 5 C atoms, and "alkoxy" means an alkoxy group having 1 to 5 C atoms, preferably 2 to 4 C atoms.

其中該丙基、丁基及戊基為直鏈基團。 Preferably, the LC medium comprises one or more compounds selected from the group consisting of formulas IV-1-1 to IV-1-9

Wherein the propyl, butyl and pentyl are linear groups.

Excellently, the LC medium according to the invention comprises one or more compounds of formula IV-2-1 and/or IV-2-2

Excellently, the LC medium according to the invention comprises a compound of formula IV-3, in particular selected from the group consisting of formulas IV-3-1 to IV-3-4

Excellently, the LC medium according to the invention comprises a compound of formula IV-4, in particular selected from compounds of formula IV-4-1 and IV-4-2

其中 R ⁴¹及R ⁴²各彼此獨立地表示具有至多12個C原子之直鏈烷基、烷氧基、烯基、烷氧基烷基或烷氧基，且

表示

Z ⁴表示單鍵、-CH ₂CH ₂-、-CH=CH-、-CF ₂O-、-OCF ₂-、-CH ₂O-、-OCH ₂-、-COO-、-OCO-、-C ₂F ₄-、-C ₄H ₈-或-CF=CF-。 The LC medium preferably additionally comprises one or more compounds of formula IVa

wherein R ⁴¹ and R ⁴² each independently represent straight-chain alkyl, alkoxy, alkenyl, alkoxyalkyl or alkoxy having up to 12 C atoms, and

express

Z ⁴ represents a single bond, -CH ₂ CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO-, - C ₂ F ₄ -, -C ₄ H ₈ - or -CF=CF-.

其中alkyl及alkyl*各彼此獨立地表示具有1至6個C原子之直鏈烷基。 The following indicate preferred compounds of formula IVa:

wherein alkyl and alkyl* each independently represent a straight-chain alkyl group having 1 to 6 C atoms.

The LC media according to the invention preferably comprise at least one compound of formula IVa-1 and/or formula IVa-2.

The proportion of the compound of formula IVa in the mixture as a whole is preferably at least 5% by weight.

其中 「alkyl」及「alkyl*」          各彼此獨立地表示具有1至6個C原子之直鏈烷基，且 「alkenyl」及「alkenyl*」   各彼此獨立地表示具有2至6個C原子之直鏈烯基。 Preferably, the LC medium comprises one or more compounds of formula IVb-1 to IVb-3

Wherein "alkyl" and "alkyl*" each independently represent a straight-chain alkyl group having 1 to 6 C atoms, and "alkenyl" and "alkenyl*" each independently represent a straight-chain alkyl group having 2 to 6 C atoms. Alkenyl.

The proportion of biphenyls of the formulas IV-1 to IV-3 in the mixture as a whole is preferably at least 3% by weight, in particular ≧5% by weight.

Among the compounds of formula IVb-1 to IVb-3, the compound of formula IVb-2 is particularly preferred.

其中「alkyl*」表示具有1至6個C原子之烷基及較佳地表示正丙基。 Particularly preferred biphenyls are

Wherein "alkyl*" represents an alkyl group having 1 to 6 C atoms and preferably represents an n-propyl group.

The LC media according to the invention particularly preferably comprise one or more compounds of the formula IVb-1-1 and/or IVb-2-3.

其中 R ⁵¹及R ⁵²彼此獨立地具有針對R ⁴¹及R ⁴²給定之含義中之一者及較佳地表示具有1至7個C原子之烷基，較佳地正烷基，特別佳地具有1至5個C原子之正烷基，具有1至7個C原子之烷氧基，較佳地正烷氧基，特別佳地具有2至5個C原子之正烷氧基，具有2至7個C原子，較佳地具有2至4個C原子之烷氧基烷基、烯基或烯氧基，較佳地烯氧基，

、

相同或不同地表示

其中

較佳地表示

或

， Z ⁵¹，Z ⁵²各彼此獨立地表示-CH ₂-CH ₂-、-CH ₂-O-、-CH=CH-、-C≡C-、-COO-或單鍵，較佳地-CH ₂-CH ₂-、-CH ₂-O-或單鍵及特別佳地單鍵，且 n                為1或2。 In a preferred embodiment, the LC medium comprises one or more compounds of formula V

wherein R ⁵¹ and R ⁵² independently of each other have one of the meanings given for R ⁴¹ and R ⁴² and preferably represent an alkyl group having 1 to 7 C atoms, preferably a normal alkyl group, particularly preferably having 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, having 2 to 7 C atoms, preferably alkoxyalkyl, alkenyl or alkenyloxy having 2 to 4 C atoms, preferably alkenyloxy,

,

express the same or differently

in

better represent

or

, Z ⁵¹ , Z ⁵² each independently represent -CH ₂ -CH ₂ -, -CH ₂ -O-, -CH=CH-, -C≡C-, -COO- or a single bond, preferably -CH ₂ -CH ₂ -, -CH ₂ -O- or a single bond and particularly preferably a single bond, and n is 1 or 2.

其中R ¹及R ²具有以上針對R ^2A指定之含義。 Compounds of formula V are preferably selected from compounds of formulas V-1 to V-16

wherein R ¹ and R ² have the meanings specified above for R ^2A .

R ¹ and R ² preferably each independently represent a linear alkyl or alkenyl group.

Preferred LC media comprise one or more of formulas V-1, V-3, V-4, V-6, V-7, V-10, V-11, V-12, V-14, V-15 and/or or V-16 compound.

The LC media according to the invention very particularly preferably comprise compounds of the formulas V-10, V-12, V-16 and/or IV-1, in particular in amounts of 5 to 30%.

The following indicate preferred compounds of formula V-10:

The LC media according to the invention particularly preferably comprise tricyclic compounds of formula V-10a and/or V-10b in combination with one or more bicyclic compounds of formula IV-1. The total proportion of the combination of compounds of the formula V-10a and/or V-10b and one or more compounds selected from the bicyclohexyl compounds of the formula IV-1 is 5 to 40%, very particularly preferably 15 to 35%.

Very particularly good LC media include compounds V-10a and IV-1-1

Compounds V-10a and IV-1-1 are preferably present in these LC media at a concentration of 15 to 35%, particularly preferably 15 to 25% and especially preferably 18 to 22%, based on the mixture as a whole.

。 Another particularly preferred LC medium comprises compounds V-10b and IV-1-1:

.

Compounds V-10b and IV-1-1 are preferably present in these LC media at a concentration of 15 to 35%, particularly preferably 15 to 25% and especially preferably 18 to 22%, based on the mixture as a whole.

。 In addition, a particularly preferred LC medium contains the following three compounds:

.

Compounds V-10a, V-10b and IV-1-1 are preferably present in these in a concentration of 15 to 35%, particularly preferably 15 to 25% and especially preferably 18 to 22%, based on the mixture as a whole in LC medium.

其中R ⁴¹及R ⁴²及R ⁵¹及R ⁵²具有以上指定之含義。較佳地，於化合物V-6、V-7及IV-1中，R ⁴¹及R ⁵¹表示各自具有1至6個或2至6個C原子之烷基或烯基，且R ⁴²及R ⁵²表示具有2至6個C原子之烯基。 Preferred LC media comprise at least one compound selected from the group consisting of

wherein R ⁴¹ and R ⁴² and R ⁵¹ and R ⁵² have the meanings specified above. Preferably, in compounds V-6, V-7 and IV-1, R ⁴¹ and R ⁵¹ represent an alkyl or alkenyl group each having 1 to 6 or 2 to 6 C atoms, and R ⁴² and R ⁵² represents an alkenyl group having 2 to 6 C atoms.

其中alkyl表示具有1至6個C原子之烷基且alkenyl表示具有2至6個C原子之烯基。 Preferred LC media comprise at least one compound of formula V-6a, V-6b, V-7a, V-7b, IV-4-1, IV-4-2, IV-3a and IV-3b:

wherein alkyl represents an alkyl group having 1 to 6 C atoms and alkenyl represents an alkenyl group having 2 to 6 C atoms.

Compounds of formula V-6a, V-6b, V-7a, V-7b, IV-4-1, IV-4-2, IV-3a and IV-3b are preferably 1 to 40% by weight, preferably An amount of 5 to 35% by weight and very particularly preferably 10 to 30% by weight is present in the LC medium according to the invention.

其中 R ⁷各彼此獨立地具有式IIA中針對R ^2A所指定之含義中之一者，且 w及x      各彼此獨立地表示1至6。 In a preferred embodiment of the present invention, the LC medium additionally comprises one or more compounds selected from the group consisting of formulas VI-1 to VI-9

wherein R ⁷ each independently has one of the meanings specified for R ^2A in formula IIA, and w and x each independently represent 1 to 6.

Particular preference is given to LC media comprising at least one compound of formula VI-9.

其中 R表示具有1至6個C原子之直鏈烷基或烷氧基，(O)表示-O-或單鍵，X表示F、Cl、OCF ₃或OCHF ₂，L ^x表示H或F，m為0、1、2、3、4、5或6且n為0、1、2、3或4。 In a preferred embodiment of the present invention, the LC medium additionally comprises one or more compounds selected from the group consisting of formulas VII-1 to VII-25

Wherein R represents a linear alkyl or alkoxy group with 1 to 6 C atoms, (O) represents -O- or a single bond, X represents F, Cl, OCF ₃ or OCHF ₂ , L ^x represents H or F, m is 0, 1, 2, 3, 4, 5 or 6 and n is 0, 1, 2, 3 or 4.

R preferably represents methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy.

X preferably represents F or OCH ₃ , most preferably F.

The LC media according to the invention preferably comprise terphenyls of the formulas VII-1 to VII-25 in an amount of 2 to 30% by weight, in particular 5 to 20% by weight.

Particularly preferred are compounds of the formulas VII-1, VII-2, VII-4, VII-20, VII-21 and VII-22, wherein X represents F. In these compounds, R preferably represents an alkyl group, and an alkoxy group, each having 1 to 5 C atoms. In compounds of formula VII-20, R preferably represents alkyl or alkenyl, in particular alkyl. In the compound of formula VII-21, R preferably represents an alkyl group. In the compounds of formulas VII-22 to VII-25, X preferably represents F.

The terphenyls of the formulas VII-1 to VII-25 are preferably employed in the LC media according to the invention if the Δn value of the mixture will be > 0.1. Preferred LC media comprise from 2 to 20% by weight of one or more terphenyl compounds selected from the group of compounds of formulas VII-1 to VII-25.

其中R、(O)及「alkyl」具有以上針對式III所指定之含義。 Other preferred embodiments are listed below: a) LC medium, which comprises at least one compound selected from the group consisting of formulas Z-1 to Z-14

wherein R, (O) and "alkyl" have the meanings specified above for formula III.

其中R ^1N及R ^2N各彼此獨立地具有針對R ^2A所指定之含義，較佳地表示直鏈烷基、直鏈烷氧基或直鏈烯基，且 Z ¹及Z ²各彼此獨立地表示-C ₂H ₄-、-CH=CH-、-(CH ₂) ₄-、-(CH ₂) ₃O-、-O(CH ₂) ₃-、-CH=CHCH ₂CH ₂-、-CH ₂CH ₂CH=CH-、-CH ₂O-、-OCH ₂-、-COO-、-OCO-、-C ₂F ₄-、-CF=CF-、-CF=CH-、-CH=CF-、-CF ₂O-、-OCF ₂-、-CH ₂-或單鍵。 b) preferred LC media according to the invention comprise one or more substances containing tetrahydronaphthyl or naphthyl units, such as, for example, compounds of the formulas N-1 to N-5,

Wherein R ^1N and R ^2N each independently have the meaning specified for R ^2A , preferably represent straight-chain alkyl, straight-chain alkoxy or straight-chain alkenyl, and Z ¹ and Z ² each independently represent -C ₂ H ₄ -, -CH=CH-, -(CH ₂ ) ₄ -, -(CH ₂ ) ₃ O-, -O(CH ₂ ) ₃ -, -CH=CHCH ₂ CH ₂ -, -CH ₂ CH ₂ CH=CH-, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO-, -C ₂ F ₄ -, -CF=CF-, -CF=CH-, -CH=CF -, -CF ₂ O-, -OCF ₂ -, -CH ₂ - or a single bond.

其中 R ^B1、R ^B2、R ^CR1、R ^CR2、R ¹、R ²各彼此獨立地具有R ^2A之含義。c為0、1或2。R ¹及R ²較佳地彼此獨立地表示具有1至6個C原子之烷基或烷氧基。 c) preferably the LC medium comprises one or more compounds selected from the group of difluorodibenzophenanthrene compounds of formula BC, phenanthrene compounds of formula CR and phenanthrene fluorides of formula PH-1 and PH-2,

Wherein R ^B1 , R ^B2 , R ^CR1 , R ^CR2 , R ¹ , R ² each independently have the meaning of R ^2A . c is 0, 1 or 2. R ¹ and R ² preferably independently of each other represent an alkyl or alkoxy group having 1 to 6 C atoms.

The LC media according to the invention preferably comprise compounds of the formula BC, CR, PH-1, PH-2 in amounts of 3 to 20% by weight, in particular 3 to 15% by weight.

其中 「alkyl」及「alkyl*」  各彼此獨立地表示具有1至6個C原子之直鏈烷基，且 「alkenyl」及「alkenyl*」          各彼此獨立地表示具有2至6個C原子之直鏈烯基。 Particularly preferred compounds of formula BC and CR are compounds BC-1 to BC-7 and CR-1 to CR-5,

Wherein "alkyl" and "alkyl*" each independently represent a straight-chain alkyl group having 1 to 6 C atoms, and "alkenyl" and "alkenyl*" each independently represent a straight-chain alkyl group having 2 to 6 C atoms. Alkenyl.

Very particular preference is given to LC media comprising one, two or three compounds of the formula BC-2, BF-1 and/or BF-2.

其中 R ¹¹、R ¹²、R ¹³各彼此獨立地表示具有1至6個C原子之直鏈烷基、烷氧基、烷氧基烷基或烯基， R ¹²及R ¹³另外表示鹵素，較佳地F，

表示

i                 表示0、1或2。 d) a preferred LC medium comprises one or more indane compounds of formula In,

wherein R ¹¹ , R ¹² , and R ¹³ each independently represent straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl having 1 to 6 C atoms, R ¹² and R ¹³ additionally represent halogen, and Jiadi F,

express

i represents 0, 1 or 2.

Preferred compounds of formula In are compounds of formulas In-1 to In-16 designated below:

Particularly preferred are compounds of the formulas In-1, In-2, In-3 and In-4.

The formula In and the subformulas In-1 to In-16 are preferably employed in the LC medium according to the invention in concentrations of ≥5% by weight, in particular from 5 to 30% by weight and very particularly preferably from 5 to 25% by weight compound.

其中 R及R ¹各彼此獨立地具有以上式IIA中針對R ^2A所指定之含義，且alkyl表示具有1至6個C原子之烷基。參數s表示1或2。 e) a preferred LC medium additionally comprises one or more compounds of formulas L-1 to L-5,

wherein R and R ¹ each independently of one another have the meanings specified for R ^2A in formula IIA above, and alkyl represents an alkyl group having 1 to 6 C atoms. Parameter s means 1 or 2.

The compounds of the formulas L-1 to L-5 are preferably employed in concentrations of 5 to 50% by weight, in particular 5 to 40% by weight and very particularly preferably 10 to 40% by weight.

其中R ¹¹及R ¹²具有以上式IIA中針對R ^2A所給定之含義中之一者，且L ¹及L ²相同或不同地表示F或Cl。 f) preferably the LC medium additionally comprises one or more compounds of formula IIA-Y

wherein R ¹¹ and R ¹² have one of the meanings given for R ^2A in the above formula IIA, and L ¹ and L ² represent F or Cl identically or differently.

其中，Alkyl及Alkyl*各彼此獨立地表示具有1至6個C原子之直鏈烷基，Alkoxy表示具有1至6個C原子之直鏈烷氧基，Alkenyl及Alkenyl*各彼此獨立地表示具有2至6個C原子之直鏈烯基，且O表示氧原子或單鍵。Alkenyl及Alkenyl*較佳地表示CH ₂=CH-、CH ₂=CHCH ₂CH ₂-、CH ₃-CH=CH-、CH ₃-CH ₂-CH=CH-、CH ₃-(CH ₂) ₂-CH=CH-、CH ₃-(CH ₂) ₃-CH=CH-或CH ₃-CH=CH-(CH ₂) ₂-。 Preferred formula IIA-Y compounds are selected from the group consisting of the following subformulas

Wherein, Alkyl and Alkyl* each independently represent a straight-chain alkyl group with 1 to 6 C atoms, Alkoxy represents a straight-chain alkoxy group with 1 to 6 C atoms, and Alkenyl and Alkenyl* each independently represent a straight-chain alkyl group with 1 to 6 C atoms. A straight-chain alkenyl group with 2 to 6 C atoms, and O represents an oxygen atom or a single bond. Alkenyl and Alkenyl* preferably represent CH ₂ =CH-, CH ₂ =CHCH ₂ CH ₂ -, CH ₃ -CH=CH-, CH ₃ -CH ₂ -CH=CH-, CH ₃ -(CH ₂ ) ₂ -CH=CH-, CH ₃ -(CH ₂ ) ₃ -CH=CH- or CH ₃ -CH=CH-(CH ₂ ) ₂ -.

其中Alkoxy及Alkoxy*具有以上所定義之含義且較佳地表示甲氧基、乙氧基、正丙氧基、正丁氧基或正戊氧基。 Particularly preferred compounds of formula IIA-Y are selected from the group consisting of the following subformulas:

wherein Alkoxy and Alkoxy* have the meanings defined above and preferably represent methoxy, ethoxy, n-propoxy, n-butoxy or n-pentoxy.

其中 R ^Q為具有1至9個C原子之烷基、烷氧基、氧雜烷基或烷氧基烷基，或具有2至9個C原子之烯基或烯氧基，所有視情況經氟化， X ^Q為F、Cl、具有1至6個C原子之鹵代烷基或烷氧基或具有2至6個C原子之鹵代烯基或烯氧基， L ^Q1至L ^Q6彼此獨立地為H或F，其中L ^Q1至L ^Q6中之至少一者為F。 g) LC medium additionally comprising one or more tetraphenyl compounds selected from the group consisting of:

wherein R ^Q is alkyl, alkoxy, oxaalkyl or alkoxyalkyl having 1 to 9 C atoms, or alkenyl or alkenyloxy having 2 to 9 C atoms, all optionally by Fluorinated, X ^Q is F, Cl, haloalkyl or alkoxy having 1 to 6 C atoms or haloalkenyl or alkenyl oxy having 2 to 6 C atoms, L ^Q1 to L ^Q6 independently of each other is H or F, wherein at least one of L ^Q1 to L ^Q6 is F.

Preferred compounds of formula Q are those wherein R ^Q represents a straight chain alkyl group having 2 to 6 C atoms, very preferably ethyl, n-propyl or n-butyl.

Preferred compounds of formula Q are those wherein L ^Q3 and L ^Q4 are F. Further preferred compounds of formula Q are those wherein L ^Q3 , L ^Q4 and one or both of L ^Q1 and L ^Q2 are F.

Preferred compounds of formula Q are those wherein ^XQ represents F or _OCF3 , most preferably F.

其中R ^Q具有上文及下文給定之式Q之含義中之一者或其較佳含義中之一者，且較佳地為乙基、正丙基或正丁基。 The compound of formula Q is preferably selected from the following sub-formulas

wherein R ^Q has one of the meanings given above and below for formula Q or one of its preferred meanings, and is preferably ethyl, n-propyl or n-butyl.

Especially preferred are compounds of formula Q1, in particular those wherein R ^Q is n-propyl.

Preferably, the proportion of the compound of formula Q in the LC host mixture is >0 to ≤5% by weight, preferably 0.05 to 2% by weight, more preferably 0.1 to 1% by weight, most preferably 0.1 to 0.8% by weight.

Preferably, the LC medium contains 1 to 5, preferably 1 or 2, compounds of formula Q.

Addition of the tetraphenyl compound of formula Q to the LC host mixture enables to reduce the ODF inhomogeneity of the LC medium while maintaining high UV absorption, enables fast and complete polymerization, enables strong and rapid generation of tilt angles, and increases UV stability .

Furthermore, the addition of compounds of formula Q with positive dielectric anisotropy to LC media with negative dielectric anisotropy allows better control of the values of the permittivity ε _|| and ε _⊥ and in particular enables the achievement of high The dielectric constant ε _|| value while maintaining the dielectric anisotropy Δε constant, thereby reducing kickback voltage and reducing image sticking.

The LC medium according to the invention preferably comprises - one or more compounds of formula I or subformulae thereof, preferably in a total concentration in the range from 0.001% to 0.02%, more preferably from 0.002% to 0.015%, most preferably from 0.005% to 0.015%, and/or - one or more compounds of formula IIA, preferably in a total concentration in the range of 5% to 30%, more preferably 7% to 25%, especially preferably 10% to 20%; and/or - one or more compounds of formula IIA and IIB, preferably in a total concentration ranging from 30% to 45%; and/or - one or more compounds of formula IV, preferably in a total concentration ranging from 35% to 70%, more preferably from 40% to 65%, especially preferably from 45% to 60%; and/or - one or more compounds of formula IV-3, preferably in a total concentration in the range of 35% to 60%, more preferably 40% to 55%, especially preferably 45% to 50%; and/or - one or more compounds of formula III-2, preferably compounds of formula III-2-6, preferably in the range of 2% to 25%, more preferably 5% to 15%, especially preferably 5% to 12% total concentration within.

。 In particular, the medium comprises - one or more compounds CY-n-Om, in particular CY-3-O4, CY-5-O4 and/or CY-3-O2, preferably at 5% to 30% , preferably a total concentration in the range of 10% to 20%; and/or - one or more compounds PY-n-Om, in particular PY-3-O2 and/or PY-1-O2, preferably In total concentrations ranging from 5% to 30%, preferably 5% to 20%; and/or - CPY-n-Om, in particular CPY-2-O2, CPY-3-O2 and/or CPY - 5-O2, preferably at a concentration of > 5%, in particular 7% to 20% based on the mixture as a whole, and/or - one or more compounds CCY-n-Om, preferably CCY-4 -O2, CCY-3-O2, CCY-3-O3, CCY-3-O1 and/or CCY-5-O2, preferably > 3% based on the mixture as a whole, in particular 5% to 15% % concentration; and/or - one or more compounds CPY-n-Om, preferably CPY-2-O2 and/or CPY-3-O2, preferably > 3% based on the mixture as a whole, specified In other words a concentration of 5% to 15%; and/or - CLY-n-Om, preferably CLY-2-O4, CLY-3-O2 and/or CLY-3-O3, preferably on a basis as a whole > 5% of the mixture, in particular 10% to 30%, preferably 15% to 20% concentration; and/or - CPY-n-Om and CY-n-Om, preferably on a basis as a whole The concentration of the mixture is 10 to 80%, and/or -CPY-n-Om and PY-n-Om, preferably CPY-2-O2 and/or CPY-3-O2 and PY-3-O2 or PY -1-O2, preferably at a concentration of 5 to 20%, more preferably 10 to 15% based on the mixture as a whole and/or -CC-3-V, preferably at a concentration of 5 to 15% based on the mixture as a whole to a concentration of 50%, and/or - the compound of formula CC-3-V1, with a total concentration in the range of 5 to 40%, more preferably 15% to 35%, particularly preferably 20% to 30%, and/or or - one or more compounds of formula B-nO-Om and/or B(S)-nO-Om, specifically compounds B(S)-2O-O4 and/or B(S)-2O-O5, compared Preferably at a concentration in the range of 2 to 12%, and/or - 0.1% to 3% of compound PPGU-3-F, and/or - compound B(S)-(c5)1O-O2:

.

Furthermore, the invention relates to an electro-optic display with active matrix addressing, characterized in that it contains a liquid crystal medium according to claim 1 as dielectric and wherein the display is VA, SA-VA, IPS, U-IPS, FFS, UB -FFS, SA-FFS, PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS, PS-posi-VA, PS-TN, polymer stabilized SA-VA or polymer stabilized The SA-FFS display.

The liquid-crystalline media according to the invention preferably have a nematic phase of ≤-20°C to ≥70°C, particularly preferably ≤-30°C to ≥80°C, very particularly preferably ≤-40°C to ≥90°C.

The medium according to the invention preferably has a clarification temperature of 70° C. or higher, very preferably 74° C. or higher.

The LC medium preferably has a nematic LC phase.

The expression "having a nematic phase" here means that on the one hand no smectic phase and no crystallization is observed at the corresponding temperature at low temperatures and on the other hand that clarification does not yet appear upon heating from the nematic phase. The investigations at low temperatures were carried out in a flow viscometer at the corresponding temperature and verified 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 a temperature of -20°C if the storage stability in the corresponding test unit is 1000 hours or more at this temperature. At temperatures of -30°C and -40°C, the corresponding times are 500 hours and 250 hours, respectively. At elevated temperatures, the clearing point is measured by known methods in capillaries.

The liquid-crystalline mixture preferably has a nematic range of at least 60 K and a fluid viscosity ν ₂₀ of at most 30 mm ² ·s ^-1 at 20° C.

The mixture is nematic at a temperature of -20°C or lower, preferably -30°C or lower, most preferably -40°C or lower.

The birefringence value Δn of the liquid crystal mixture is generally between 0.07 and 0.16, preferably between 0.08 and 0.15, very preferably between 0.09 and 0.14.

In a preferred embodiment of the invention, the medium has a birefringence in the range of 0.090 to 0.110, preferably 0.095 to 0.105, in particular 0.100 to 0.105.

In another preferred embodiment, the medium according to the invention has a birefringence of 0.120 or more, preferably in the range of 0.125 to 0.145, more preferably 0.130 to 0.140.

The liquid crystal mixtures according to the invention have a dielectric anisotropy Δε of -1.5 to -8.0, preferably -2.0 to -4.0, in particular -2.5 to -3.5.

The rotational viscosity γ ₁ at 20°C is preferably ≤120 mPa∙s, in particular ≤100 mPa∙s.

In a preferred embodiment, the rotational viscosity _γ1 at 20°C is ≤ 100 mPa·s, specifically ≤ 95 mPa·s.

The liquid-crystalline media according to the invention have relatively low threshold voltage (V ₀ ) values. It is preferably in the range of 1.7 V to 3.0 V, particularly preferably ≦2.7 V and very particularly preferably ≦2.5 V.

For the present invention, unless otherwise specified, the term "threshold voltage" refers to the capacitance threshold (V ₀ ), also known as the Freedericks threshold.

Furthermore, the liquid-crystalline media according to the invention have high voltage retention values in liquid crystal cells.

In general, liquid crystal media with low addressing or threshold voltages exhibit lower voltage retention than those with higher addressing or threshold voltages and vice versa.

For the present invention, the term "dielectrically positive compound" means a compound having Δε > 1.5, the term "dielectrically neutral compound" means those having -1.5 ≤ Δε ≤ 1.5 and the term "dielectrically negative compound" means having Δε < -1.5 those. The dielectric anisotropy of the compounds here is determined by dissolving 10% of the compound in a liquid crystal host and measuring the capacitance of the resulting mixture at 1 kHz in each case in at least one test cell with a diameter of 20 µm Layer thickness and vertical and uniform surface alignment. The measured voltages are typically 0.5 V to 1.0 V, but are always below the capacitance threshold of the respective liquid crystal mixtures studied.

All temperature values specified for this invention are in °C.

The LC medium according to the invention is suitable for all VA-TFT ( Vertical Alignment Thin Film Transistor ) applications, such as, for example, VAN ( Vertical Alignment Nematic ), MVA ( Multi-Domain VA), (S)-PVA ( Super Patterned VA), ASV ( Advanced Large Viewing Angle , or Axisymmetric VA), or UV ² A. Furthermore, it is suitable for IPS ( In-Plane Switching ) and FFS ( Fringe Field Switching ) applications with negative Δε.

The nematic LC medium in the displays according to the invention generally comprises two components NA and NB, which themselves consist of one or more individual compounds.

Component NA has a significant negative dielectric anisotropy and provides a dielectric anisotropy of ≤-0.5 to the nematic phase. In addition to one or more compounds of formula I, it preferably comprises compounds of formula IIA, IIB and/or IIC and, furthermore, one or more compounds of formula IV-1.

The proportion of component NA is preferably between 45 and 100%, in particular between 60 and 85%.

For component NA, one (or more) individual compounds are preferably selected having a value of ≤ -0.8. The more negative this value must be, the smaller the proportion of NA in the mixture as a whole.

Component NB has obvious nematogeneity and a fluid viscosity at 20°C of not more than 30 mm ² ∙ s ^‑1 , preferably not more than 25 mm ² ∙ s ^‑1 .

Particularly preferred individual compounds of component NB are very low-viscosity nematic liquid crystals having a flow viscosity at 20° C. of not more than 18 mm ² ∙ s ^‑1 , preferably not more than 12 mm ² ∙ s ^‑1 .

Component NB is unidirectional or anti-nematic, does not have smectic phase and can prevent smectic phase from appearing in LC medium at very low temperature. For example, if various materials with high nematicity are added to the smectic liquid crystal mixture, the nematicity of these materials can be compared by the degree of suppression of the smectic phase.

The mixture may optionally also comprise a component NC comprising compounds having a dielectric anisotropy of Δε≧1.5. These so-called positive compounds are generally present in mixtures with negative dielectric anisotropy in an amount of ≦20% by weight, based on the mixture as a whole.

In addition to one or more compounds of formula I or a subformula thereof, the medium preferably comprises 4 to 15, in particular 5 to 12, and particularly preferably <10 compounds of formula IIA, IIB and/or IIC and optionally one or more compounds of formula IV-1.

In addition to compounds of formula I or subformulas thereof and compounds of formulas IIA, IIB and/or IIC and optionally IV-1, other components may, for example, be up to 45%, but preferably up to 35%, based on the mixture as a whole %, specifically in an amount of at most 10%.

The other constituents are preferably selected from nematic or nematic-forming substances, in particular known substances from the following classes: azobenzene oxide, benzylidene aniline, biphenyl, terphenyl, phenyl benzoate or Cyclohexyl benzoate, phenyl cyclohexanecarboxylate or cyclohexyl cyclohexanecarboxylate, phenylcyclohexane, cyclohexylbiphenyl, cyclohexylcyclohexane, cyclohexylnaphthalene, 1,4-bicyclohexylbiphenyl Benzene or cyclohexylpyrimidine, phenyldioxane or cyclohexyldioxane, optionally halogenated toluene, benzylphenyl ether, tolan and substituted cinnamate.

其中L及E各表示來自由經1,4-二取代之苯及環己烷環、經4,4’-二取代之聯苯、苯基環己烷及環己基環己烷體系、經2,5-二取代之嘧啶及1,3-二噁烷環、經2,6-二取代之萘、二氫萘及四氫萘、喹唑啉及四氫喹唑啉形成之基團之碳環或雜環環體系， G表示                    -CH=CH- -N(O)=N- -CH=CQ- -CH=N(O)- -C≡C‑      -CH ₂-CH ₂- -CO-O-    -CH ₂-O- -CO-S-    -CH ₂-S- -CH=N-   -COO-Phe-COO- -CF ₂O-    -CF=CF- -OCF ₂-    -OCH ₂- -(CH ₂) ₄-   -(CH ₂) ₃O- 或C-C單鍵，Q表示鹵素，較佳地氯，或-CN，且R ²⁰及R ²¹各表示具有至多18個，較佳地至多8個碳原子之烷基、烯基、烷氧基、烷氧基烷基或烷氧羰氧基，或此等基團中之一者或者表示CN、NC、NO ₂、NCS、CF ₃、SF ₅、OCF ₃、F、Cl或Br。 The most important compounds suitable as constituents of liquid crystalline phases of this type can be characterized by the formula IV

Among them, L and E each represent a system consisting of 1,4-disubstituted benzene and cyclohexane ring, 4,4'-disubstituted biphenyl, phenylcyclohexane and cyclohexylcyclohexane system, via 2 , 5-disubstituted pyrimidine and 1,3-dioxane ring, 2,6-disubstituted naphthalene, dihydronaphthalene and tetrahydronaphthalene, quinazoline and tetrahydroquinazoline group carbon Ring or heterocyclic ring system, G means -CH=CH- -N(O)=N- -CH=CQ- -CH=N(O)- -C≡C‑ -CH ₂ -CH ₂ - -CO- O- -CH ₂ -O- -CO-S- -CH ₂ -S- -CH=N- -COO-Phe-COO- -CF ₂ O- -CF=CF- -OCF ₂ - -OCH ₂ - - (CH ₂ ) ₄ - -(CH ₂ ) ₃ O- or CC single bond, Q represents halogen, preferably chlorine, or -CN, and R ²⁰ and R ²¹ each represent at most 18, preferably at most 8 Alkyl, alkenyl, alkoxy, alkoxyalkyl or alkoxycarbonyloxy of 2 carbon atoms, or one of these groups or represent CN, NC, NO ₂ , NCS, CF ₃ , SF _{5. OCF3} , F, Cl or Br.

In most of these compounds, R ²⁰ and R ²¹ are different from each other, and one of these groups is usually an alkyl or alkoxy group. Other variations of the suggested substituents are also common. Many of these substances, or mixtures thereof, are commercially available. All these substances can be prepared by methods known from the literature.

It goes without saying to a person skilled in the art that the VA, IPS or FFS mixtures according to the invention may also comprise compounds in which, for example, H, N, O, Cl and F have been replaced with the corresponding isotopes.

The combination of the compounds of the above-mentioned preferred embodiments and the above-mentioned polymerized compounds leads to low threshold voltages, low rotational viscosities and excellent low-temperature stability of the LC media according to the invention with simultaneously consistently high clearing points and high HR values , and allows rapid establishment of particularly low tilt angles (ie, large tilts) in PSA displays. In particular, the LC medium exhibits a significantly shortened response time in PSA displays compared to LC media from the prior art, in particular also the grayscale response time.

Furthermore, the invention relates to an LC display comprising an LC medium as described above and below.

The LC display is preferably a VA, IPS, FFS, UB-FFS or UV ² A display.

The structure of the display according to the invention corresponds to the usual geometry of a PSA display, as described in the prior art cited at the outset. Geometries without protrusions are preferred, in particular those in which, moreover, the electrodes on the color filter side are not structured and only the electrodes on the TFT side have slots. Particularly suitable and preferred electrode structures for PS-VA displays are described eg in US 2006/0066793 A1.

Preferred LC displays of the present invention include: - a first substrate comprising pixel electrodes defining pixel regions, the pixel electrodes being connected to switching elements arranged in each pixel region and optionally including micro-slit patterns, and optionally a first alignment layer arranged on the pixel electrodes, - a second substrate comprising a common electrode layer, which may be arranged over the entire part of the second substrate facing the first substrate, and optionally a second alignment layer, - An LC layer arranged between the first substrate and the second substrate and comprising an LC medium as described above and below.

The first alignment layer and/or the second alignment layer controls the alignment direction of LC molecules of the LC layer. For example, in a VA display, the alignment layer is chosen such that it imparts a homeotropic/vertical alignment (ie, perpendicular to the surface) or a tilted alignment to the LC molecules. This alignment layer may, for example, comprise polyimide, which may also be rubbed, or may be prepared by photo-alignment methods. In ^UV2A displays, alignment layers are prepared by photopolymerization using linearly polarized UV light and irradiation at oblique angles.

The LC layer with the LC medium can be deposited between the substrates of the display by methods customary to display manufacturers, eg the so-called one-drop-fill (ODF) method.

The LC display may contain additional elements such as color filters, black matrix, passivation layers, light blocking layers, transistor elements for addressing individual pixels, etc., all of which are well known to those skilled in the art and may be developed without the skill of the present invention. use.

The electrode structure can be designed by a skilled person depending on the individual display type. For example, for VA displays, multi-domain orientation of LC molecules can be induced by providing electrodes with slits and/or bumps or protrusions to create two, four or more different slanted alignment directions.

In addition to the compound of formula I, the LC medium may also contain one or more further stabilizers. Suitable types and amounts of stabilizers are known to those skilled in the art and are described in the literature. Particularly suitable are, for example, commercially available stabilizers from the Irganox® range (Ciba AG), such as, for example, Irganox® 1076. If a stabilizer is used, its proportion is preferably 10 to 5000 ppm, particularly preferably 50 to 500 ppm.

In a preferred embodiment, the LC medium contains one or more chiral dopants, preferably at a concentration of 0.01 to 1% by weight, very preferably 0.05 to 1.0% by weight. The chiral dopant is preferably selected from the group consisting of the compounds of the following Table B, and is preferably selected from R- or S-1011, R- or S-2011, R- or S-3011, R- or S A group consisting of -4011 and R- or S-5011.

In another preferred embodiment, the LC medium contains a racemate of one or more chiral dopants, preferably selected from the pair mentioned in the previous paragraph chiral dopant.

In addition, for example 0 to 15% by weight of pleochroic dyes, in addition to nanoparticles, a conductive salt for improving conductivity, preferably 4-hexyloxybenzoic acid ethyl dimethyl dodecane complex salts of tetrabutylammonium tetraphenylborate or crown ethers (reference, for example, Haller et al., Mol. Cryst. Liq. Cryst. 24 , 249-258 (1973)), or for modifying The dielectric anisotropy, viscosity and/or alignment of the phase is added to the LC medium. Substances of this type are described, for example, in DE-A 22 09 127, 22 40 864, 23 21 632, 23 38 281, 24 50 088, 26 37 430 and 28 53 728.

The individual components of the above-listed preferred embodiments of the LC media according to the invention are known or their preparation methods can easily be derived from the prior art by a person skilled in the relevant art, since it is based on what is described in the literature standard method. Corresponding compounds of the formula CY are described, for example, in EP-A-0 364 538 . Corresponding compounds of the formula ZK are described, for example, in DE-A-26 36 684 and DE-A-33 21 373 .

The LC media which can be used according to the invention are in a manner known per se, for example by mixing one or more of the compounds mentioned above with one or more compounds of the formula I as defined above, and optionally with further liquid crystals Compounds and/or additives are mixed to prepare. In general, the required amount of the component used in the lesser amount is dissolved in the component making up the main component, advantageously at elevated temperature. It is also possible to mix solutions containing components in organic solvents such as acetone, chloroform or methanol, and to remove the solvent again, for example by distillation, after thorough mixing. Furthermore, the invention relates to a process for preparing the LC media according to the invention.

It goes without saying to those skilled in the art that the LC medium according to the invention may also comprise compounds in which for example H, N, O, Cl, F have been replaced by corresponding isotopes such as deuterium or the like.

The following examples illustrate the invention without limiting it. However, it shows to the person skilled in the art the concept of preferred mixtures and the compounds which are preferably employed and their respective concentrations and combinations with each other. Furthermore, the examples illustrate which properties and combinations of properties are achievable.

Preferred mixture components are shown in Table A below.

Table A In Table A, m and n are independently integers from 1 to 12, preferably 1, 2, 3, 4, 5 or 6, and k is 0, 1, 2, 3, 4, 5 or 6 , and (O)C _m H _2m+1 means C _m H _2m+1 or OC _m H _2m+1 .

In a preferred embodiment of the invention, the LC medium according to the invention comprises one or more compounds selected from the group consisting of compounds from Table A.

Table B Table B shows possible chiral dopants that can be added to the LC media according to the invention.

The LC medium preferably comprises 0 to 10% by weight, in particular 0.01 to 5% by weight, particularly preferably 0.1 to 3% by weight, of dopants. The LC medium preferably comprises one or more dopants selected from the group consisting of compounds from Table B.

Table C Table C shows possible stabilizers that can be added to the LC media according to the invention. Wherein n represents an integer from 1 to 12, preferably 1, 2, 3, 4, 5, 6, 7 or 8, and does not show a terminal methyl group.

The LC medium preferably comprises 0 to 10% by weight, in particular 1 ppm to 5% by weight, particularly preferably 1 ppm to 1% by weight, of stabilizer. The LC medium preferably comprises one or more stabilizers selected from the group consisting of compounds from Table C.

EXAMPLES The following examples illustrate the invention without limiting it. However, it shows to the person skilled in the art the preferred mixture perspective and the compounds which are preferably employed and their respective concentrations and combinations with each other. Furthermore, the examples illustrate which properties and combinations of properties are achievable.

In addition, the following abbreviations and symbols are used: V ₀ threshold voltage at 20°C, capacitance [V], _ne extraordinary refractive index at 20°C and 589 nm, n _o at 20°C and 589 nm Ordinary refractive index, Δn Optical anisotropy at 20°C and 589 nm, ε _⊥ Permittivity perpendicular to the director at 20°C and 1 kHz, ε _|| parallel to the director at 20°C and 1 kHz Dielectric constant of Δε, dielectric anisotropy at 20°C and 1 kHz, cl.p., T(N,I) clearing point [°C], rotational viscosity of _γ1 at 20°C [mPa∙s ], K ₁ elastic constant, "unfolding" deformation at 20°C [pN], K ₂ elastic constant, "torsion" deformation at 20°C [pN], K ₃ elastic constant, "bending" at 20°C "Deformation [pN].

Unless expressly stated otherwise, all concentrations in this application are quoted in % by weight and relative to the corresponding mixture as a whole, comprising all solid or liquid crystalline components, solvent-free.

Unless expressly specified otherwise, terms specified in this application such as, for example, for melting point T(C,N), smectic (S) to nematic (N) phase transition T(S,N) and clarification All temperature values at point T(N,I) are quoted in degrees Celsius (°C). M.p. means melting point, cl.p. = clearing point. Furthermore, C = crystalline state, N = nematic phase, S = smectic phase and I = isotropic phase. The data between these symbols represent the transition temperature.

Unless expressly specified otherwise 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 apply at a temperature of 20°C, and Δn was measured at 589 nm and Δε was measured at 1 kHz.

Unless otherwise specified, the term "threshold voltage" used in the present invention refers to the capacitance threshold (V ₀ ), also known as the Fredericks threshold. In the examples, the optical threshold can also be quoted as usual at 10% relative contrast (V ₁₀ ).

Unless otherwise specified, methods of preparing test units and measuring their electro-optic and other properties were performed by methods as described below or analogous thereto.

Unless otherwise specified, the term "tilt angle" means the angle between the LC director and the substrate, and "LC director" means the preferred orientation of the optical principal axis of the LC molecules in a layer of uniformly oriented LC molecules. The orientation direction, which in the case of a rod-shaped uniaxial positive birefringence LC molecule, corresponds to its molecular long axis.

Example 1 Nematic LC host mixture N1 is formulated as follows B(S)-2O-O5 4.00 % cl.p. 75.9°C BCH-32 1.00 % Δn 0.0951 CC-3-V 30.00 % Δε -2.7 CCH-23 13.00 % | ₁ 89 ^mPa.s CCH-34 9.00 % K ₁ 13.3 CCY-3-O2 4.00 % K ₃ 13.3 CPY-2-O2 12.00 % V ₀ 2.37V CPY-3-O2 12.00 % CY-3-O2 9.00 % PGIY-2-O4 6.00 %

Stabilized mixture S1.1 was prepared by adding 100 ppm of compound M1 according to formula I to nematic LC host mixture N1.

Stabilized mixture S1.2 was prepared by adding 200 ppm of compound M1 according to formula I to nematic LC host mixture N1.

Comparative Example 1 mixture C1 was prepared by adding 300 ppm of compound M1 to nematic LC host mixture N1.

Example 2 Nematic LC host mixture N2 is formulated as follows CC-3-V1 10.00 % cl.p. 74.1°C CCH-301 6.00 % Δn 0.1024 CCH-35 2.50 % ε _|| 4.000 CCP-3-1 8.00 % ε _⊥ 8.7 CCP-3-3 3.00 % Δε -4.7 CCY-3-1 7.00 % K ₁ 14.4 CCY-3-O1 5.00 % K ₃ 17.7 CCY-3-O2 12.00 % V ₀ 2.005V CCY-5-O2 8.00 % | ₁ 147 mPa ^. s CY-3-O2 15.00 % CY-3-O4 4.50 % PY-1-O2 10.50 % PY-2-O2 8.50 %

Stabilized mixture S2 was prepared by adding 150 ppm of compound M1 to nematic LC host mixture N2.

Example 3 Nematic LC host mixture N3 is formulated as follows CC-3-V1 7.50 % cl.p. 74.2°C CCH-301 4.50 % Δn 0.1079 CCH-34 7.00 % ε _|| 3.9 CCH-35 6.00 % ε _⊥ 8.4 CCP-3-1 8.00 % Δε -4.5 CCY-3-O1 7.00 % K ₁ 14.5 CCY-3-O2 12.00 % K ₃ 16.7 CPY-3-O2 12.00 % V ₀ 2.04V CY-3-O2 15.50 % | ₁ 135 ^mPa.s PY-2-O2 11.00 % PY-3-O2 9.50 %

Stabilized mixture S3 was prepared by adding 100 ppm of compound M1 to nematic LC host mixture N3.

Example 4 Nematic LC host mixture N4 is formulated as follows B(S)-2O-O4 4.00 % cl.p. 74.6°C B(S)-2O-O5 4.00 % Δn 0.1162 BCH-32 7.50 % ε _|| 3.6 CC-3-V 25.75 % ε _⊥ 6.3 CC-3-V1 10.00 % Δε -2.7 CCP-3-1 13.00 % K ₁ 14.7 CCP-3-3 3.25 % K ₃ 14.9 CLY-3-O2 2.00 % V ₀ 2.48V CPY-2-O2 9.50 % | ₁ 78 ^mPa.s PY-1-O2 11.00 % PY-2-O2 10.00 %

Stabilized mixture S4.1 was prepared by adding 100 ppm of compound M1 to nematic LC host mixture N4.

Stabilized mixture S4.2 was prepared by adding 200 ppm of compound M1 to nematic LC host mixture N4.

Example 5 Nematic LC host mixture N5 is formulated as follows B(S)-2O-O4 2.00 % cl.p. 73.9°C B(S)-2O-O5 2.50 % Δn 0.1165 BCH-32 8.00 % ε _|| 3.6 CC-3-V 30.00 % ε _⊥ 6.3 CC-4-V1 7.00 % Δε -2.7 CCP-3-1 11.00 % K ₁ 14.1 CLY-3-O2 3.00 % K ₃ 14.7 CPY-2-O2 2.00 % V ₀ 2.46V CPY-3-O2 12.00 % | ₁ 79 ^mPa.s PY-1-O2 11.50 % PY-2-O2 11.00 %

Stabilized mixture S5 was prepared by adding 100 ppm of compound M1 to nematic LC host mixture N5.

Example 6 Nematic LC host mixture N6 is formulated as follows BCH-32 10.00 % cl.p. 74.6°C CC-3-V1 6.50 % Δn 0.1113 CCH-34 8.00 % ε _|| 3.5 CCH-35 8.00 % ε _⊥ 6.8 CCY-3-O2 12.00 % Δε -3.3 CPY-2-O2 6.50 % K ₁ 14.5 CPY-3-O2 11.00 % K ₃ 15.3 CY-3-O2 15.00 % V ₀ 2.28V CY-5-O2 13.00 % | ₁ 128 mPa ^. s PP-1-4 10.00 %

Stabilized mixture S6 was prepared by adding 150 ppm of compound M1 to nematic LC host mixture N6.

Example 7 Nematic LC host mixture N7 is formulated as follows BCH-32 1.75 % cl.p. 74.4°C CC-3-V1 9.00 % Δn 0.1019 CCH-34 6.00 % ε _|| 3.6 CCH-35 6.00 % ε _⊥ 7.2 CCP-3-1 7.00 % Δε -3.6 CCP-3-3 5.00 % K ₁ 15.2 CCY-3-O1 6.00 % K ₃ 17.9 CCY-3-O2 12.00 % V ₀ 2.35V CPY-3-O2 4.25 % | ₁ 126 ^mPa.s CY-3-O2 15.25 % CY-5-O2 4.75 % PCH-302 8.00 % PY-3-O2 15.00 %

Stabilized mixture S7 was prepared by adding 100 ppm of compound M1 to nematic LC host mixture N7.

Example 8 Nematic LC host mixture N8 is formulated as follows CC-3-V1 9.00 % cl.p. 75.4°C CC-4-V1 12.00 % Δn 0.1193 CCH-34 8.00 % ε _|| 3.5 CCP-3-1 8.00 % ε _⊥ 6.7 CCP-3-3 0.50 % Δε -3.2 CCY-3-O2 12.50 % K ₁ 16.3 CPY-3-O2 13.00 % K ₃ 18.7 CY-3-O2 10.00 % V ₀ 2.56V PP-1-2V1 9.50 % | ₁ 111 ^mPa.s PY-1-O2 10.00 % PY-2-O2 7.50 %

Stabilized mixture S8 was prepared by adding 150 ppm of compound M1 to nematic LC host mixture N8.

Example 9 Nematic LC host mixture N9 is formulated as follows BCH-32 5.75 % cl.p. 74.7°C CC-3-V1 11.00 % Δn 0.1138 CCH-301 7.75 % ε _|| 3.6 CCH-34 6.00 % ε _⊥ 6.5 CCH-35 8.00 % Δε -2.9 CCP-3-1 0.75 % K ₁ 14.3 CCP-V2-1 9.50 % K ₃ 15.5 CCY-3-1 1.25 % V ₀ 2.43V CCY-3-O2 5.00 % | ₁ CPY-2-O2 10.50 % CPY-3-O2 5.00 % CY-3-O2 4.50 % PCH-301 1.50 % PY-1-O2 7.50 % PY-2-O2 2.50 % PY-3-O2 13.50 %

Stabilized mixture S9 was prepared by adding 150 ppm of compound M1 to nematic LC host mixture N9.

Example 10 Nematic LC host mixture N10 is formulated as follows B(S)-2O-O4 3.00 % cl.p. 74.9°C B(S)-2O-O5 5.00 % Δn 0.1154 BCH-32 7.00 % ε _|| 3.6 CC-3-V 29.50 % ε _⊥ 6.3 CC-3-V1 9.00 % Δε -2.7 CCP-3-1 11.00 % K ₁ 14.3 CCP-3-3 2.00 % K ₃ 14.9 CLY-3-O2 2.00 % V ₀ 2.48V CPY-2-O2 6.50 % | ₁ 77 ^mPa.s CPY-3-O2 5.50 % PY-1-O2 10.50 % PY-2-O2 9.00 %

Stabilized mixture S10.1 was prepared by adding 100 ppm of compound M1 to nematic LC host mixture N10.

Stabilized mixture S10.2 was prepared by adding 200 ppm of compound M1 to nematic LC host mixture N10.

Example 11 Nematic LC host mixture N11 is formulated as follows B(S)-2O-O4 3.00 % cl.p. 75.8°C CC-3-V1 7.00 % Δn 0.1056 CCH-23 15.00 % ε _|| 3.5 CCH-301 3.00 % ε _⊥ 6.8 CCH-34 3.00 % Δε -3.3 CCH-35 7.00 % K ₁ 15.8 CCP-3-1 6.00 % K ₃ 17.2 CCY-3-O1 8.00 % V ₀ 2.40V CCY-3-O2 8.50 % | ₁ 108 ^mPa.s CPY-3-O2 12.00 % CY-3-O2 11.00 % PP-1-2V1 6.50 % PY-1-O2 10.00 %

Stabilized mixture S11 was prepared by adding 100 ppm of compound M1 to nematic LC host mixture N11.

Example of use The VHR of the stabilized mixtures S1.1 and S1.2 containing compound M1 according to the invention was measured compared to the pure host mixture N1.

VHR Measurements The test cell for VHR measurements consisted of two plane-parallel glass outer plates separated by 3.2 μm, each of which had an electrode layer on the inside and a polyimide alignment layer on top, of which two polyimide The imine layer achieves vertical alignment of the liquid crystal molecules and applies photo-alignment to induce tilt directions on the two substrates crossing each other.

Six test units were prepared for each LC mixture. After filling the LC mixture, the cells are sealed by a sealant. Then, the VHR of host mixture N1 and mixtures S1.1 and S1.2 were measured at 60°C with an applied voltage of 1 V/0.6 Hz before and after BL stress at 60°C for 120 hours. Light and thermal stress generally cause the generation of impurities and ions that reduce the VHR of the LC mixture, so the smaller the absolute reduction in VHR value after stress, the better the performance for display applications.

The results are shown in Table 1. Table 1 - VHR mixture Initial VHR (%) VHR (%) after 120 hours BL stress N1 94.1 80.4 S1.1 95.1 84.2 S1.2 94.5 88.4

It can be seen from Table 1 that for mixtures S1.1 and S1.2 according to the invention, the initial VHR is already higher than that of the host mixture N1 without compound M1. After 120 hours of BL stress, the VHR of host mixture N1 showed a strong decrease, while the VHR of mixtures S1.1 and S1.2 showed a much smaller decrease.

Tilt Angle Measurements The tilt angle generation of the stabilized mixture S1.1 according to the invention was compared with the pure host mixture N1 and with the comparative mixture C1 with a higher amount of compound M1.

The test cell for tilt angle measurement consisted of two plane-parallel glass outer plates separated by 3.2 μm, each of which had an electrode layer on the inside and a polyimide alignment layer on top, where the two polyimide layer to achieve vertical alignment of the liquid crystal molecules and to apply photo-alignment to induce tilt directions at the two substrates that are antiparallel to each other.

The LC mixture was filled into test cells, which were then sealed by a sealant. The generated tilt angles in host mixture N1 and mixtures S1.1 and C1 were measured before and after 120 hours of exposure to BL and an electrical stress of 60 Vpp using a Mueller Matrix polarimeter " AxoScan " from Axometrics.

The change in inclination angle after stress, ie, the absolute value of inclination angle change Δtilt is shown in Table 2 below. Table 2 - Slope change mixture Δtilt / ° N1 0.77 S1.1 0.72 C1 3.57

As can be seen from Table 2, the mixture S1.1 according to the invention with 100 ppm of compound M1 shows a small change in tilt angle, which is similar to the main mixture N1, which means that no significant tilt angle is produced by this concentration of compound M1 . In contrast, the comparative mixture C1 with 300 ppm of compound M1 shows a stronger change in the tilt angle, which indicates that the tilt angle has developed.

Taken together, the above results show that when compounds of formula I are added to nematic host mixtures at low concentrations, VHR can be increased without showing significant tilt angle generation.

Claims (17)

A LC medium comprising one or more compounds of formula I in a concentration of > 0% by weight and ≤ 0.02% by weight

wherein the individual groups independently of one another and identically or differently at each occurrence have the following meanings P CW=CH-CO-O-, W H, F, Cl, CF ₃ or an alkyl group having 1 to 5 C atoms , preferably H or CH ₃ , Sp ¹ , Sp ² , Sp ³ spacer or single bond, LF, Cl, -CN, P-Sp- or a straight chain, branched chain or chain with 1 to 25 C atoms Cyclic alkyl, wherein one or more non-adjacent CH ₂ -groups are optionally connected via -O-, -S-, -CO-, - CO-O-, -O-CO-, -O-CO-O-, CR ⁰ =CR ⁰⁰ -, -C≡C-,

,

,

,

,

or

substituted, and wherein one or more H atoms are each optionally replaced by P-Sp-, F or Cl, r, s 0, 1, 2, 3 or 4, and additionally comprise one or more compounds of formula II

wherein these individual groups independently of each other and each occurrence the same or differently have the following meanings R ¹ , R ² are linear, branched or cyclic alkyl groups having 1 to 25 C atoms, one or more of which Non-adjacent CH ₂ -groups optionally via -O-, -S-, -CO-, -CO-O-, -O-CO- , -O-CO-O-, CR ⁰ =CR ⁰⁰ -, -C≡C-,

,

,

,

,

or

Replacement, and wherein one or more H atoms are replaced by F or Cl as appropriate, A ¹ and A ² are selected from the groups of the following formula

Z ¹ , Z ² -CH ₂ CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -CO-O-, -O-CO -, -C ₂ F ₄ -, -CF=CF-, -CH=CH-CH ₂ O- or single bond, L ¹ , L ² , L ³ , L ⁴ F, Cl, OCF ₃ , CF ₃ , CH _3. CH ₂ F or CHF ₂ , Y H, F, Cl, CF ₃ , CHF ₂ or CH ₃ , L ^C CH ₃ or OCH ₃ , a1 1 or 2, a2 0 or 1. The LC medium as claimed in item 1, wherein in the compound of formula I, P is acrylate or methacrylate. The LC medium according to claim 1 or 2, wherein in the compound of formula I, L represents F, Cl, CN or OCH ₃ . The LC medium as claimed in item 1, wherein in the compound of formula I, at least one group Sp is different from a single bond. The LC medium according to claim 1, wherein if Sp is different from a single bond, it is selected from -(CH ₂ ) ₂ -, -(CH ₂ ) ₃ -, -(CH ₂ ) ₄ -, -O-(CH ₂ ) ₂ -, -O-(CH ₂ ) ₃ -, -O-CO-(CH ₂ ) ₂ and -CO-O-(CH) ₂ -, wherein the O atom or the CO group is connected to The benzene ring. As the LC medium of claim item 1, wherein the compound of the formula I is selected from the following subformulas:

Wherein P has the meaning of claim 1 or 2, and L has the meaning of claim 3, and Sp' has one of the meanings of Sp given in claim 1 or 6, which is different from a single bond. As the LC medium of claim item 1, wherein the compound of the formula I is selected from the following subformulas:

. The LC medium as claimed in item 1, wherein it contains one or more compounds of formula II selected from the group consisting of compounds of formula IIA, IIB, IIC and IID

wherein R ^2A and R ^2B each independently represent H, an alkyl or alkenyl group having up to 15 C atoms, which is unsubstituted, monosubstituted with CN or CF ₃ or at least monosubstituted with halogen, furthermore, wherein One or more of the _CH2 groups in the group can be connected via -O-, -S-,

,

,

,

,

,

, -C≡C-, -CF ₂ O-, -OCF ₂ -, -OC-O- or -O-CO- replacement, L ¹ to L ⁴ each independently represent F, Cl, CF ₃ or CHF ₂ , Y represents H, F, Cl, CF ₃ , CHF ₂ or CH ₃ , preferably H or CH ₃ , especially preferably H, Z ² , Z ^2B and Z ^2D each independently represent a single bond, -CH ₂ CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO-, -C ₂ F ₄ -, -CF= CF-, -CH=CHCH ₂ O-, p represents 0, 1 or 2, and q represents 0 or 1 identically or differently each time it appears. The LC medium as claimed in item 1, wherein it additionally comprises one or more compounds of formula III

wherein R ¹¹ and R ¹² each independently represent H, an alkyl or alkoxy group having 1 to 15 C atoms, wherein one or more _CH groups in these groups may each be independently such that The O atoms are not directly connected to each other by means of

,

,

,

,

,

, -O-, -S-, -C≡C-, -CF ₂ O-, -OCF ₂ -, -CH=CH-, -OC-O- or -O-CO-, and in addition, one of or multiple H atoms may be replaced by halogen, each occurrence of A ³ independently of each other represents a) 1,4-cyclohexenyl or 1,4-cyclohexylene, wherein one or two non-adjacent CH ₂ groups may be replaced by -O- or -S-, b) a 1,4-phenylene group in which one or both CH groups may be replaced by N, or c) a group selected from the group consisting of: Spiro[3.3]heptane-2,6-diyl, 1,4-bicyclo[2.2.2]octene, naphthalene-2,6-diyl, decalin-2,6-diyl, 1,2 , 3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl and fluorene-2,7-diyl, wherein these groups a), b) and c) can be modified by halogen Atom single substitution or multi-substitution, n represents 0, 1 or 2, preferably 0 or 1, and each occurrence of Z ¹ independently represents -CO-O-, -O-CO-, -CF ₂ O- , -OCF ₂ -, -CH ₂ O-, -OCH _{2 -, -CH 2 -} , -CH ₂ CH ₂ -, -(CH ₂ ) ₄ -, -CH=CH-CH ₂ O-, -C ₂ F ₄ -, -CH ₂ CF ₂ -, -CF ₂ CH ₂ -, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C- or a single bond , L ¹¹ and L ¹² each independently represent F, Cl, CF ₃ or CHF ₂ , preferably H or F, most preferably F, and W represents O or S. The LC medium as claimed in item 1, wherein it additionally comprises one or more compounds of formula IV

Wherein ^R represents unsubstituted alkyl with 1 to 7 C atoms or unsubstituted alkenyl with 2 to 7 C atoms, preferably n-alkyl, particularly preferably with 2, 3, 4 or 5 C atoms, and R represents ^{unsubstituted} alkyl having 1 to 7 C atoms or unsubstituted alkoxy having 1 to 6 C atoms, both of which preferably have 2 to 5 C atoms, unsubstituted alkenyl having 2 to 7 C atoms, preferably 2, 3 or 4 C atoms, more preferably vinyl or 1-propenyl and in particular vinyl. The LC medium as claimed in item 1, wherein it comprises one or more compounds of formula IV-3

Wherein "alkyl" means an alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms, and "alkenyl" means having 2 to 5 C atoms, preferably 2 to 4 C atoms , particularly preferably an alkenyl group with 2 C atoms. The LC medium as claimed in item 1, wherein it additionally comprises one or more compounds of formula V

wherein R ⁵¹ and R ⁵² independently of each other have one of the meanings given for R ⁴¹ and R ⁴² and preferably represent an alkyl group having 1 to 7 C atoms, preferably a normal alkyl group, particularly preferably having 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, having 2 to 7 C atoms, preferably alkoxyalkyl, alkenyl or alkenyloxy having 2 to 4 C atoms, preferably alkenyloxy,

,

express the same or differently

in

better represent

or

, Z ⁵¹ , Z ⁵² each independently represent -CH ₂ -CH ₂ -, -CH ₂ -O-, -CH=CH-, -C≡C-, -COO- or a single bond, preferably -CH ₂ -CH ₂ -, -CH ₂ -O- or a single bond and particularly preferably a single bond, and n is 1 or 2. The LC medium according to claim 1, wherein it further comprises one or more additives selected from the group consisting of stabilizers and chiral dopants. A method for preparing a LC medium as any one of claims 1 to 13, comprising one or more compounds of formula I as defined in any one of claims 1 to 7 and any one of claims 1 or 12 A step of mixing one or more compounds of the formulas II, III, IV and/or V as defined in one item, optionally with further liquid crystal compounds and/or additives. An LC display comprising the LC medium as defined in any one of claims 1 to 13. As the LC display of claim 15, it is a display in VA, IPS, FFS or UV2A mode. The LC display of claim 15 or 16, wherein it comprises two substrates, at least one of which is transparent to light, one electrode provided on each substrate or two electrodes provided on only one of the substrates, and a layer of the LC medium according to any one of claims 1 to 13 located between the substrates.