Liquid-crystalline medium

Abstract

The present invention relates to liquid-crystalline (LC) media comprising stabilizers for optical, electro-optical and electronic purposes, in particular for use in LC displays, especially in LC displays of the vertical alignment mode, to LC displays of the vertical alignment mode comprising said LC media, and to a process for the production of said LC displays.

Description

[0001] This invention relates to liquid crystal (LC) media containing stabilizers for optical, electro-optical and electronic purposes, particularly for use in LC displays, especially in vertical alignment mode LC displays, vertical alignment mode LC displays containing said LC media, and methods for manufacturing said LC displays.

[0002] The proliferation of 8K and gaming monitors has led to increased demand for LC display (LCD) panels with higher refresh rates, and consequently, for LC media with faster response times. Many of these LCD panels utilize a display mode in which LC molecules are aligned substantially perpendicular or slightly tilted relative to the electrode surfaces in a cut state.

[0003] Therefore, so-called VA ("vertically aligned") displays are known, which have wide viewing angles and fast response times. The LC cell of a VA display contains an LC dielectric layer between two transparent electrodes, where the LC dielectric typically has a negative dielectric anisotropy (Δε). In the off state, the molecules of the LC layer are vertically aligned to the electrode surfaces (vertical plane) or have an inclined vertical alignment. When a voltage is applied to the two electrodes, a reorientation of the LC molecules parallel to the electrode surfaces occurs.

[0004] Furthermore, so-called FFS (“edge field switching”) displays have been reported (see especially SH Jung et al., Jpn. J. Appl. Phys., Vol. 43, No. 3, 2004, 1028), which contain two electrodes on the same substrate, one of which is structured in a comb-like manner and the other is unstructured. This generates a strong so-called “edge field,” that is, a strong electric field near the edge of the electrode, and an electric field with both strong vertical and strong horizontal components throughout the cell. FFS displays have low viewing angle dependence on contrast. FFS displays typically contain an LC dielectric with positive dielectric anisotropy and an alignment layer, typically polyimide, which provides planar alignment for the molecules of the LC dielectric.

[0005] FFS displays can operate as either active matrix or passive matrix displays. In the case of an active matrix display, individual pixels are typically addressed by integrated nonlinear active elements, such as transistors (e.g., thin-film transistors (“TFTs”)), while in the case of a passive matrix display, individual pixels are typically addressed by multiplexing methods, as known in the art.

[0006] Also known is the so-called IPS (“in-plane switching”) display, which includes a planar LC layer between two substrates, with two electrodes disposed on only one of the two substrates, and preferably having a cross-shaped comb structure. When a voltage is applied to the electrodes, an electric field with a significant component parallel to the LC layer is generated between them. This leads to the reorientation of LC molecules in the layer plane.

[0007] Furthermore, FFS displays have been disclosed (see SHLee et al., Appl. Phys. Lett. 73(20), 1998, 2882-2883 and SHLee et al., Liquid Crystals 39(9), 2012, 1141-1148), which have similar electrode designs and layer thicknesses to FFS displays, but contain layers of LC dielectric with negative dielectric anisotropy instead of LC dielectric with positive dielectric anisotropy. Compared to LC dielectric with positive dielectric anisotropy, LC dielectric with negative dielectric anisotropy displays exhibit a more favorable director orientation with less tilt and more twist orientation, resulting in higher transmittance.

[0008] In addition, VA displays, also known as UV displays, have been publicly disclosed that use alignment layers prepared by photo-alignment. 2 Mode A (see, for example, Q. Tang et al., SID Symposium Digest of Technical Papers 2018, 414-417). These displays utilize alignment layers prepared by oblique irradiation with linearly polarized UV light from crosslinkable and photooriented monomers or prepolymers, such as cinnamate chromophores. As a result, a crosslinked alignment layer is formed, which induces uniaxial alignment with a pre-tilted angle in LC molecules near its surface. By changing the irradiation direction, multidomain structures with different pre-tilted orientations can be obtained.

[0009] However, there are several disadvantages to using LC media with negative dielectric anisotropy in VA or FFS displays. For example, they have significantly lower reliability compared to LC media with positive dielectric anisotropy.

[0010] The term "reliability" as used below refers to the performance quality of a display over a period of time and under various stress loads (e.g., light load, temperature, humidity, or voltage) that cause display defects such as image adhesion (area and line image adhesion), uneven display, and yogore, and is known to those skilled in the art of LC displays. As a standard parameter for classifying reliability, the voltage retention rate (VHR) value is commonly used, which is a measure of maintaining a constant voltage in a tested display. A higher VHR value indicates better media reliability.

[0011] The reduced reliability of LC media with negative dielectric anisotropy in VA or FFS displays can be explained by the interaction between LC molecules and the polyimide alignment layer. As a result, ions are extracted from the polyimide alignment layer, and the LC molecules with negative dielectric anisotropy extract these ions more effectively.

[0012] This has led to new requirements for the LC media used in VA or FFS displays. In particular, the LC media must exhibit high reliability and a high VHR value after UV exposure. Further requirements include high specific resistivity, a wide operating temperature range, short response time even at low temperatures, low threshold voltage, multiple gray levels, high contrast and wide viewing angle, and reduced image adhesion.

[0013] Therefore, in displays known in the prior art, the undesirable effect of so-called "image sticking" or "image burning" is often observed, in which the image generated in an LC display by temporary addressing of a single pixel remains visible even after the electric field in these pixels has been cut off, or after other pixels have been addressed.

[0014] On the one hand, this "image adhesion" occurs when using an LC dielectric with a low VHR. The UV component of sunlight or backlight causes undesirable decomposition reactions of the LC molecules therein, thus initiating the generation of ionic or free radical impurities. These can accumulate particularly at the electrodes or alignment layers, where they can reduce the effectively applied voltage.

[0015] Another problem observed in the prior art is that LC media used in displays (including but not limited to VA and FFS displays) often exhibit high viscosity, and therefore 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, LC media containing alkenyl compounds have been observed to frequently exhibit reduced reliability and stability, as well as a decrease in VHR, especially after exposure to UV radiation and visible light from display backlights that typically do not emit UV light.

[0016] To mitigate the decrease in reliability and stability, the use of stabilizers, such as HALS- (hindered amine light stabilizers) type compounds, is proposed. A typical example is Tinuvin 770, a compound with the following formula:

[0017]

[0018] However, these LC mixtures still exhibit insufficient reliability during display operation, such as when illuminated with typical CCFL (cold cathode fluorescent lamp) backlight.

[0019] Different types of compounds used to stabilize liquid crystals are phenol-derived antioxidants, such as those described in DE19539141 A1.

[0020]

[0021] This stabilizer can be used to stabilize LC mixtures against the effects of heat or oxygen, but it generally does not show any advantage under light stress.

[0022] Due to the complex modes of action of different types of stabilizers and the subtle effects in displays, where liquid crystals (which are themselves complex mixtures of many different types of compounds) interact with different species (including polyimides), selecting the right stabilizer to identify the optimal material combination is a challenging task for technicians. Therefore, there remains a significant need for novel stabilizers with different properties to broaden the applicability of materials.

[0023] Therefore, one object of the present invention is to provide a method for using an improved LC medium for VA-, IPS-, or FFS displays that does not exhibit the aforementioned disadvantages or exhibits them only to a small extent, and has improved performance. Another object of the present invention is to provide an FFS display with good transmittance, high reliability, particularly a VHR value after backlight exposure, high resistivity, a wide operating temperature range, short response time even at low temperatures, low threshold voltage, multiple gray levels, high contrast, wide viewing angle, and reduced image adhesion.

[0024] It has been found that one or more of these purposes can be achieved by providing LC media as disclosed and claimed below.

[0025] In particular, the inventors of this invention have discovered that the above-mentioned objective can be achieved by using an LC medium containing a small amount of a stabilizer in VA-, IPS, or FFS displays, said stabilizer being a compound of Formula I described below. It has also been found that, surprisingly, when such a stabilizer is used in LC media for FFS displays, the reliability and VHR value after backlight loading are significantly higher compared to LC media without the stabilizer according to the invention.

[0026] Furthermore, the use of LC media containing the stabilizers described below allows for the utilization of the known advantages of alkenyl-containing LC media, such as reduced viscosity and faster switching time, while simultaneously resulting in improved reliability and high VHR values, especially after backlight exposure.

[0027] Therefore, the present invention relates to LC media comprising one or more compounds of formula I at a concentration >0 wt% and ≤0.02 wt%.

[0028]

[0029] Each group is independent of the others and, each time it appears, has the same or different meanings as follows:

[0030] P is CW=CH-CO-O-,

[0031] W is H, F, Cl, CF3 or an alkyl group having 1-5 C atoms, preferably H or CH3, Sp 1 Sp 2 Sp 3 The spacer group or single bond can be optionally substituted with P.

[0032] L is F, Cl, -CN, P-Sp- or a straight-chain, branched or cyclic alkyl group having 1-25 C atoms, wherein one or more non-adjacent CH2- groups are optionally represented by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-, CR-, or -O-CO-O- in such a manner that the O- and / or S- atoms are not directly connected to each other. 0 =CR 00 -、-C≡C-、

[0033] or

[0034] The substitutions are made, and one or more H atoms are optionally substituted by P-Sp-, F or Cl, where r and s are 0, 1, 2, 3 or 4, preferably 0, 1 or 2.

[0035] And further includes one or more compounds of formula II

[0036]

[0037] Each group is independent of the others and, each time it appears, has the same or different meanings as follows:

[0038] R 1 R 2 It is a straight-chain, branched, or cyclic alkyl group having 1-25 carbon atoms, wherein one or more non-adjacent CH2 groups are optionally configured such that the O- and / or S- atoms are not directly connected to each other by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-, -O-CO-O-, CR 0 =CR 00 -、-C≡C-、

[0039]

[0040] The substitutions, wherein one or more H atoms are optionally replaced by F or Cl, preferably alkyl or alkoxy groups having 1-6 C atoms,

[0041] A 1 A 2 Groups selected from the following formulas

[0042]

[0043]

[0044] Preferred formulas A1, A2, A3, A4, A5, A6, A9, and A10; Very preferred formulas A1, A2, A3, A4, A5, A9, and A10.

[0045] Z 1 Z 2 The bond type can be -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CO-O-, -O-CO-, -C2F4-, -CF=CF-, -CH=CH-CH2O-, or a single bond, preferably a single bond.

[0046] L 1 L 2 L 3 L 4 The solvent is F, Cl, OCF3, CF3, CH3, CH2F, or CHF2, with F or Cl being preferred, and F being very preferred.

[0047] Y can be H, F, Cl, CF3, CHF2, or CH3, with H or CH3 being preferred, and H being highly preferred.

[0048] L C It is CH3 or OCH3, preferably CH3.

[0049] a1 is 1 or 2.

[0050] a2 is 0 or 1.

[0051] The present invention also relates to LC media in LC displays as described in the context, preferably in VA, IPS, FFS, UB-FFS, or UV. 2 Applications in LC displays in Mode A.

[0052] LC dielectrics exhibit negative dielectric anisotropy.

[0053] The present invention also relates to a method for preparing LC media as described in the context, comprising the steps of mixing one or more compounds of formula I with one or more compounds of formula II and optionally mixing with other LC compounds and / or additives.

[0054] The present invention also relates to an LC display comprising an LC medium according to the invention as described in the context, preferably VA, IPS, FFS, UB-FFS, or UV.2 LC display in mode A.

[0055] The present invention also relates to a method of manufacturing an LC display as described in the context, including the step of filling or otherwise providing an LC medium as described in the context between substrates of the display.

[0056] Surprisingly, compounds of formula I, despite having potentially reactive P groups such as acrylate or methacrylate groups, were found to be able to stabilize LC mixtures under photostress, contrary to their detrimental effects on LC reliability. It was also found that the generation of undesirable pretilt angles in LC media, typically observed when these compounds are used in VA mode displays and exposed to UV irradiation, can be suppressed if the concentration of the formula I compounds is kept sufficiently low.

[0057] It was also found that, surprisingly, when the compound of Formula I was used in LC media for VA or FFS mode displays, the reliability and VHR value after backlight loading were higher compared to LC media that did not contain the compound of Formula I according to the invention.

[0058] Furthermore, using LC media containing compounds of Formula I as described below allows for the utilization of the known advantages of alkenyl-containing LC media, such as reduced viscosity and faster switching time, while simultaneously resulting in improved reliability and high VHR values, especially after backlight exposure.

[0059] Unless otherwise stated, compounds of formula I are preferably selected from achiral compounds.

[0060] As used herein, the terms “active layer” and “switchable layer” refer to layers in electro-optic displays, such as LC displays, which contain one or more molecules with structural and optical anisotropy, such as LC molecules, that change their orientation when subjected to external stimuli such as an electric or magnetic field, resulting in a change in the layer’s transmittance to polarized or unpolarized light.

[0061] As used herein, the terms “tilt” and “tilt angle” should be understood to refer to the tilted orientation of LC molecules of the LC medium relative to the cell surface in an LC display (preferably a PSA display), and should be understood to include “pre-tilt” and “pre-tilt angle”. The tilt angle described herein represents the average angle (<90°) between the longitudinal molecular axis (LC director) of the LC molecules and the planar parallel outer surface forming the LC cell. Low absolute tilt angles (i.e., significantly deviating from 90°) correspond to large tilts. Suitable methods for measuring tilt angles are provided in the embodiments. Unless otherwise stated, tilt angle values ​​disclosed in the context are related to this measurement method.

[0062] As used herein, the term "mesocrystalline group" is known to those skilled in the art and described in the literature, and it refers to a group that substantially contributes to the formation of a liquid crystal (LC) phase in a low molecular weight or polymeric substance due to the anisotropy of its attractive and repulsive interactions. A compound containing a mesocrystalline group (mesocrystalline compound) does not necessarily have an LC phase by itself. Mesocrystalline compounds can exhibit LC phase behavior only when mixed with other compounds and / or after polymerization. Typical mesocrystalline groups are, for example, rigid rod-shaped or disk-shaped units. Terms and definitions used in connection with mesocrystalline or LC compounds are given in PureAppl.Chem. 2001, 73(5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew.Chem. 2004, 116, 6340-6368.

[0063] As used herein, the term "spacer group" (hereinafter also referred to as "Sp") is known to those skilled in the art and 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 group" means a flexible group, such as an alkylene group, attached to a mesocrystalline or polymerizable group in a polymerizable mesocrystalline compound.

[0064] In the context, Represents the trans-1,4-cyclohexyl ring, and It represents a 1,4-phenylene ring.

[0065] In groups In this system, the single bond between the two ring atoms can be attached to any free position on the benzene ring.

[0066] If the group R in the formula is shown in the context 1-12 ,R Q R or L represents alkyl and / or alkoxy, and it can be straight-chain or branched. It is preferably straight-chain, having 2, 3, 4, 5, 6 or 7 C atoms and correspondingly preferably representing ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy or heptoxy, as well as methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octyloxy, nonoxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy or tetradecyloxy.

[0067] If the group R in the formula is shown in the context 1-13 ,R 51 ,R52 ,R Q ,R,R 2A ,R 2B ,R IIIA ,R 1N ,R 2N ,R B1 ,R B2 ,R CR1 ,R CR2 R or L represents alkyl and / or alkoxy, and it can be straight-chain or branched. It is preferably straight-chain, having 2, 3, 4, 5, 6 or 7 C atoms and correspondingly preferably representing ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy or heptoxy, as well as methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octyloxy, nonoxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy or tetradecyloxy.

[0068] If the group R in the formula is shown in the context 1-13 ,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 represents an alkyl group in which one or more CH2 groups are replaced by S, and it can be straight-chain or branched. It is preferably straight-chain, having 1, 2, 3, 4, 5, 6 or 7 C atoms and correspondingly preferably representing thiomethyl, thioethyl, thiopropyl, thiobutyl, thiopentyl, thiohexyl or thioheptyl.

[0069] 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-oxaheptyl, 2-,3-,4-,5-,6- or 7-oxaoctyl, 2-,3-,4-,5-,6-,7- or 8-oxanonyl, 2-,3-,4-,5-,6-,7-,8- or 9-oxadecyl.

[0070] If the group R in the formula is shown in the context 1-13 ,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 represents alkoxy or oxalyl, and it may also contain one or more additional oxygen atoms, provided that the oxygen atoms are not directly connected to each other.

[0071] In another preferred embodiment, R 1-13 ,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 One or more of R or L are selected from the following groups

[0072]

[0073] -S 1 -F, -OS 1 -F, -O-S1-O-S2, where S 1 C 1-12 -alkylene or C 2-12 - Idemenyl and S 2 For H, C 1-12 -alkyl or C 2-12 -Alkenyl, and very preferably selected from the following groups

[0074] -OCH2OCH3, -O(CH2)2OCH3, -O(CH2)3OCH3, -O(CH2)4OCH3, -O(CH2)2F, -O(CH2)3F and -O(CH2)4F.

[0075] If the group R in the formula is shown in the context 1-13 ,R 51 ,R 52 ,R Q ,R,R 2A ,R 2B ,R IIIA ,R 1N ,R 2N ,R B1 ,R B2 ,R CR1 ,RCR2 R or L indicates an alkyl group in which one of the CH2 groups has been replaced by -CH=CH-, and it can be straight-chain or branched. It is preferably straight-chain and has 2-10 C atoms. Accordingly, it represents, in particular, 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, hep-1-, -2-, -3-, -4-, -5- or -6-enyl, oct-1-, -2-, -3-, -4-, -5-, -6- or -7-enyl, non-1-, -2-, -3-, -4-, -5-, -6-, -7- or -8-enyl, dec-1-, -2-, -3-, -4-, -5-, -6-, -7-, -8- or -9-enyl.

[0076] If the group R in the formula is shown in the context 1-13 ,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 represents an alkyl or alkenyl group that is at least monosubstituted with a halogen, preferably a straight chain, and the halogen is preferably F or Cl. In the case of multiple substitution, the halogen is preferably F. The resulting group also includes perfluorinated groups. In the case of monosubstituted substitution, the fluorine or chlorine substituent can be at any desired position, but is preferably at the ω-position.

[0077] The halogen is preferably F or Cl, with F being the most preferred.

[0078] Group -CR 0 =CR 00 - Preferably -CH=CH-.

[0079] -OC-, -CO-, -C(=O)-, and -C(O)- represent carbonyl groups, i.e.

[0080] Preferred substituents L are, for example, F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, -C(=O)N(R) x )2、-C(=O)Y 1 -C(=O)R x -N(R) x2. Straight-chain or branched alkyl, alkoxy, alkyl carbonyl, alkoxy carbonyl, alkyl carbonyloxy, or alkoxy carbonyloxy groups, each having 1-25 carbon atoms, wherein one or more H atoms may optionally be replaced by F or Cl, optionally substituted silyl groups having 1-20 Si atoms, or optionally substituted aryl groups having 6-25, preferably 6-15 carbon atoms.

[0081] Where R x Represents H, F, Cl, CN, or a straight-chain, branched, or cyclic alkyl group having 1-25 C atoms, wherein one or more non-adjacent CH2 groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-, or -O-CO-O-, such that the O- and / or S- atoms are not directly connected to each other, and wherein one or more H atoms are each optionally replaced by F, Cl, P-, or P-Sp-.

[0082] Y 1 It represents halogens.

[0083] Particularly preferred substituents L are, for example, F, Cl, CN, NO2, CH3, C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5, and phenyl.

[0084] Preferred

[0085] L has one of the meanings described above.

[0086] In Formula I and its sub-formulas, the P group is preferably selected from acrylate, methacrylate, fluoroacrylate and chloroacrylate, more preferably from acrylate and methacrylate, and most preferably P represents methacrylate.

[0087] In the most preferred formula I and its sub-formulas, all groups P have the same meaning, and most preferably represent acrylate or methacrylate groups, with methacrylate groups being the most preferred.

[0088] If the spacer group Sp 1-3 If one of the groups is different from a single bond, then it is preferably of the formula Sp"-X, so that each group P-Sp- conforms to the formula P-Sp"-X"-, wherein

[0089] "Sp" represents a linear or branched alkylene group having 1-20, preferably 1-12, carbon atoms, optionally mono- or polysubstituted with F, Cl, Br, I, or CN, wherein, in addition, one or more non-adjacent CH2 groups may be independently replaced by -O-, -S-, -NH-, or -N(R) groups such that the O and / or S atoms are not directly connected to each other. 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- can be substituted.

[0090] 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 )-, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -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 bonds

[0091] R 0 and R 00 Each independently represents H or an alkyl group having 1-20 carbon atoms, and

[0092] Y 2 and Y 3 Each can be represented independently as H, F, Cl, or CN.

[0093] X" is preferably -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, or -CO-NR. 0 -、-NR 0 -CO-、-NR 0 -CO-NR 00 - or a single key.

[0094] Typical spacer group Sp 1-3 And -Sp"-X"- is, for example, -(CH2). p1 -、-(CH2) p1 -O-、-(CH2) p1 -O-CO-、-(CH2) p1 -CO-O-、-(CH2) p1 -O-CO-O-、-(CH2CH2O) q1 -CH2CH2-, -CH2CH2-S-CH2CH2-, -CH2CH2-NH-CH2CH2- or -(SiR) 0 R 00 -O) p1 - where p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R 0 and R 00 It has the meaning described above.

[0095] The particularly preferred group Sp 1-3 And -Sp"-X"- is -(CH2) p1 -、-(CH2) p1 -O-、-(CH2) p1 -O-CO-、-(CH2) p1 -CO-O-、-(CH2) p1 -O-CO-O-, where p1 and q1 have the meanings described above.

[0096] The particularly preferred group Sp" is, in each case, a straight-chain ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene, vinylene, propenylene, and butenylene.

[0097] Preferred compounds of formula I and its derivatives are those in which the Sp group is present. 1-3 At least one of them is a compound with a single bond. Further preferred compounds of formula I and its sub-formulas are those in which the Sp group is present. 1-3 At least one of the compounds that is different from a single bond.

[0098] The most preferred formula I and its sub-formula compounds are those in which Sp 1-3 Selected from single bonds, -(CH2) p1 -、-O-(CH2) p1 -、-O-CO-(CH2) p1 and -CO-O-(CH2) p1Compounds in which p1 is 2, 3, 4, 5, or 6, and if Sp is -O-(CH2). p1 -、-O-CO-(CH2) p1 Or -CO-O-(CH2) p1 Then the O atom or CO- group is attached to the benzene ring.

[0099] Further preferred embodiments of Formula I and its sub-formulas are selected from the following preferred embodiments, including any combination thereof:

[0100] - All groups P have the same meaning, and very preferably represent acrylate or methacrylate groups, most preferably methacrylate groups.

[0101] -All Sp 1-3 They are all single keys.

[0102] -All Sp 1-3 They are all different from single keys.

[0103] -Sp 1-3 One of them is a single bond, while the other two are different from single bonds.

[0104] -Sp 1-3 One of them is different from a single bond, while the other two each represent a single bond.

[0105] -Sp 1 It is a single key, and Sp 2 and Sp 3 One or two, preferably Sp 2 and Sp 3 The two are different from single bonds.

[0106] -Sp 1-3 When not a single bond, it is selected from -(CH2)2-, -(CH2)3-, -(CH2)4-, -O-(CH2)2-, -O-(CH2)3-, -O-CO-(CH2)2-, and -CO-O-(CH)2-, wherein the O atom or CO group is attached to the benzene ring.

[0107] - group Sp 1-3 At least one of them is different from a single bond, and is selected from -(CH2)2-, -(CH2)3-, -(CH2)4-, -O-(CH2)2-, -O-(CH2)3-, -O-CO-(CH2)2-, and -CO-O-(CH)2-, wherein the O atom or CO group is attached to the benzene ring.

[0108] -Sp 1-3 When it differs from a single bond, it indicates an alkylene group with 2 to 6 carbon atoms.

[0109] -r and s are independent and can be 0, 1, or 2, and the sum of r and s is 0, 1, or 2.

[0110] -r = s = 0, or r = 0 and s = 1, or r = 1 and s = 0, or r = s = 1.

[0111] -L represents F, Cl, CN or OCH3, with F or OCH3 being the most preferred.

[0112] Further preferred compounds of formula I are selected from the following sub-formulas:

[0113]

[0114]

[0115] Wherein P and L have one of the meanings of Equation I or the preferred meanings given by the context, and Sp' has one of the meanings of Sp as given by Equation I or the preferred meanings given by the context, which is different from a single bond.

[0116] Sp' in formulas I1 to I8 is preferably selected from -(CH2)2-, -(CH2)3-, -(CH2)4-, -O-(CH2)2-, -O-(CH2)3-, -O-CO-(CH2)2- and -CO-O-(CH)2-, wherein the O atom or CO group is attached to the benzene ring.

[0117] In formulas I1 to I8, L preferably represents F, Cl, CN or OCH3, with F or OCH3 being highly preferred.

[0118] The most preferred compounds of formula I are selected from the following sub-formulas:

[0119]

[0120]

[0121]

[0122] Further preferred are compounds of formulas I1a to I6a, wherein one, two, or three methacrylate groups are replaced by acrylate groups.

[0123] The concentration of Formula I and its sub-formula compounds in the LC medium is preferably 0.001-0.02%, very preferably 0.002-0.015%, and most preferably 0.005-0.015%.

[0124] In another preferred embodiment, the concentration of Formula I and its sub-formulas in the LC medium is 10-250 ppm, preferably 20-200 ppm, and most preferably 50-150 ppm.

[0125] Compounds of Formula I can be prepared by methods similar to those known to those skilled in the art and described in standard works of organic chemistry, such as those in Houben-Weyl, Methodden der Organischen Chemie [Methods of Organic Chemistry], Thieme-Verlag, and Stuttgart.

[0126] For example, acrylates or methacrylates can be prepared by esterification of the corresponding alcohol with an acid derivative, such as (meth)acryloyl chloride or (meth)acrylic anhydride, in the presence of a base such as pyridine or triethylamine and 4-(N,N-dimethylamino)pyridine (DMAP). Alternatively, the ester can be prepared by esterification of the alcohol with (meth)acrylic acid in the presence of a dehydrating agent, such as dicyclohexylcarbodiimide (DCC), N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC), or N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride according to Steglich, and DMAP.

[0127] In addition to the compounds of Formula I described above, the LC medium for the LC display of the present invention also comprises an LC mixture (“body mixture”) comprising one or more, preferably two or more, LC compounds, preferably at least one of which is a compound of Formula II.

[0128] A particularly preferred embodiment of this LC medium is shown below.

[0129] Preferably, the LC medium contains one or more compounds of formula II selected from compounds of formulas IIA, IIB, IIC, and IID.

[0130]

[0131] in

[0132] R 2A and R 2B Each of these groups independently represents H, an alkyl or alkenyl group having up to 15 carbon atoms, which is unsubstituted, monosubstituted with CN or CF3, or at least monosubstituted with a halogen, wherein one or more CH2 groups among these groups can be used such that the O atom is not directly attached to each other by -O-, -S-,

[0133] Replace with -C≡C-, -CF₂O-, -OCF₂-, -OC-O-, or -O-CO-.

[0134] L 1 To L 4 Each can be independently represented as F, Cl, CF3, or CHF2.

[0135] Y represents H, F, Cl, CF3, CHF2, or CH3, with H or CH3 being preferred, and H being particularly preferred.

[0136] Z 2 Z 2B and Z 2D Each of these independently represents a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF-, and -CH=CHCH2O-.

[0137] p represents 0, 1, or 2, and

[0138] Each occurrence of q represents either 0 or 1, either the same or different.

[0139] Preferred compounds of formulas IIA, IIB, IIC, and IID are those in which R 2B Those that represent alkyl or alkoxy groups having a maximum of 15 carbon atoms, and very preferably (O)C. v H 2v+1 , where (O) is an oxygen atom or a single bond and v is 1, 2, 3, 4, 5 or 6.

[0140] Further preferred compounds of formulas IIA, IIB, IIC, and IID are those in which R 2A Or R 2B Those that represent or contain cycloalkyl or cycloalkoxy groups are preferably selected from...

[0141]

[0142] Where S 1 C 1-5 -alkylene or C 2-5 - Idemenyl and S 2 For H, C 1-7 -alkyl or C 2-7 -Alkenyl, and very preferably selected from

[0143]

[0144] In a preferred embodiment, the LC medium comprises one or more compounds of formula IIA selected from IIA-1 to IIA-76.

[0145]

[0146]

[0147]

[0148]

[0149]

[0150]

[0151]

[0152]

[0153]

[0154]

[0155] The index 'a' represents 1 or 2, and "alkyl" and "alkyl * Each of these terms independently represents a straight-chain alkyl group having 1 to 6 carbon atoms, "alkenyl" represents a straight-chain alkenyl group having 2 to 6 carbon atoms, and (O) represents an oxygen atom or a single bond. "alkenyl" preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH-, or CH3-CH=CH-(CH2)2-.

[0156] The LC medium particularly preferred by the present invention comprises one or more compounds selected from formulas IIA-2, IIA-8, IIA-10, IIA-16, II-18, IIA-40, IIA-41, IIA-42 and IIA-43.

[0157] In another preferred embodiment, the LC medium comprises one or more compounds of formula IIB selected from formulas IIB-1 to IIB-26.

[0158]

[0159]

[0160]

[0161]

[0162] Among them, "alkyl" and "alkyl * “,”, “alkenyl” and (O) have the meanings given above.

[0163] The LC medium particularly preferred by the present invention comprises one or more compounds selected from formulas IIB-2, IIB-10 and IIB-16.

[0164] In another preferred embodiment, the LC medium comprises one or more compounds of formula IIC-1.

[0165]

[0166] Among them, "alkyl" and "alkyl * " and (O) have the meanings given above.

[0167] In another preferred embodiment, the LC medium comprises one or more IID compounds selected from formulas IID-1 to IID-10.

[0168]

[0169]

[0170] Among them, "alkyl" and "alkyl * “,”, “alkenyl” and (O) have the meanings given above.

[0171] The particularly preferred LC media of the present invention comprises one or more compounds of formula IID-4.

[0172] The proportion of compounds of formula IIA and / or IIB in the entire mixture is preferably at least 20% by weight.

[0173] In another preferred embodiment, the LC medium comprises one or more compounds of formula III.

[0174]

[0175] in

[0176] R 11 and R 12 Each of these groups independently represents H, an alkyl or alkoxy group having 1-15 carbon atoms, wherein one or more CH2 groups among these groups can be represented independently such that the O atom is not directly connected to each other.

[0177]

[0178] -O-, -S-, -C≡C-, -CF₂O-, -OCF₂-, -CH=CH-, -OC-O-, or -O-CO- can be substituted, and in addition, one or more H atoms can be substituted by halogens.

[0179] A 3 Each occurrence represents an independent representation.

[0180] a) 1,4-cyclohexeneyl or 1,4-cyclohexeneyl, wherein one or both non-adjacent CH2 groups may be replaced by -O- or -S-.

[0181] b) 1,4-Phenylidene, wherein one or both CH groups may be replaced by N, or

[0182] c) A group selected from spiro[3.3]heptane-2,6-diyl, 1,4-bicyclo[2.2.2]octyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl, and fluorene-2,7-diyl.

[0183] Groups a), b), and c) can be mono- or poly-substituted with halogen atoms.

[0184] n represents 0, 1, or 2, preferably 0 or 1.

[0185] Z 1 Each occurrence independently represents -CO-O-, -O-CO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -(CH2)4-, -CH=CH-CH2O-, -C2F4-, -CH2CF2-, -CF2CH2-, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C-, or a single bond, and

[0186] L 11 and L 12 Each of these elements independently represents F, Cl, CF3, or CHF2, preferably H or F, with F being the most preferred.

[0187] W represents O or S.

[0188] In a preferred embodiment of the present invention, the LC medium comprises one or more compounds of formula III-1 and / or III-2.

[0189]

[0190] The groups appearing therein have the same meaning as given in Formula III above and are preferably...

[0191] R 11 and R 12 Each of the alkyl, alkenyl, or alkoxy groups having a maximum of 15 carbon atoms, more preferably one or both of which represent an alkoxy group, and

[0192] L 11 and L 12 Each is preferred, represented by F.

[0193] In another preferred embodiment, the LC medium comprises one or more compounds of formula III-1 selected from formulas III-1-1 to III-1-11, preferably formula III-1-6.

[0194]

[0195]

[0196] Among them, "alkyl" and "alkyl * "Each independently represents a straight-chain alkyl group having 1-6 carbon atoms, 'alkenyl' and 'alkenyl'" * "Each independently represents a straight-chain alkenyl group with 2-6 carbon atoms, "alkoxy" and "alkoxy" * "Each independently represents a straight-chain alkoxy group having 1-6 carbon atoms, and L..." 11 and L 12 Each can be represented independently as F or Cl, with F being the preferred choice.

[0197] In another preferred embodiment, the LC medium comprises one or more compounds of formula III-2 selected from formulas III-2-1 to III-2-10, preferably formula III-2-6.

[0198]

[0199]

[0200] Among them, "alkyl" and "alkyl * "Each independently represents a straight-chain alkyl group having 1-6 carbon atoms, 'alkenyl' and 'alkenyl'" * "Each independently represents a straight-chain alkenyl group with 2-6 carbon atoms, "alkoxy" and "alkoxy" * "Each independently represents a straight-chain alkoxy group having 1-6 carbon atoms, and L..." 11 and L 12 Each can be represented independently as F or Cl, with F being the preferred choice.

[0201] In a highly preferred embodiment, the LC medium comprises one or more compounds selected from the following formulas.

[0202]

[0203] In another preferred embodiment of the invention, the LC medium comprises one or more compounds of formula IIIA-1 and / or IIIA-2.

[0204]

[0205] Where L 11 and L 12 Having the same meaning as given in Equation III, (O) represents O or a single bond.

[0206] R IIIA This refers to an alkyl or alkenyl group, or a Cy-C group, having a maximum of 7 carbon atoms. m H 2m+1 -,

[0207] m and n are the same or different from 0, 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, very preferably 1, and

[0208] Cy represents an alicyclic group having 3, 4, or 5 ring atoms, which may be optionally alkyl or alkenyl groups having a maximum of 3 C atoms, or substituted with halogen or CN, and preferably represents cyclopropyl, cyclobutyl, or cyclopentyl.

[0209] Compounds of formula IIIA-1 and / or IIIA-2 may replace compounds of formula III or be additionally contained in the LC medium, preferably additionally.

[0210] The most preferred compounds of formula IIIA-1 and IIIA-2 are as follows:

[0211]

[0212]

[0213] Wherein “alkoxy” represents a straight-chain alkoxy group having 1-6 carbon atoms, and preferably represents n-propoxy, n-butoxy, n-pentoxy or n-hexoxy.

[0214] In a preferred embodiment of the present invention, the LC medium comprises one or more compounds of formula III-3.

[0215]

[0216] in

[0217] R 11 ,R 12 The same or different representations of H, alkyl or alkoxy groups having 1-15 C atoms, wherein one or more CH2 groups of these groups are optionally independently represented such that the O atoms are not directly connected to each other by -C≡C-, -CF2O-, -OCF2-, -CH=CH-,

[0218]

[0219] -O-, -S-, -CO-O-, or -O-CO- are used as substitutes, and one or more H atoms may be substituted with halogens.

[0220] Compounds of formula III-3 are preferably selected from formulas III-3-1 to III-3-11:

[0221]

[0222]

[0223] Where R 12 The alkyl group having 1 to 7 carbon atoms is preferred to be ethyl, n-propyl, n-butyl, n-pentyl or n-hexyl, or alternatively cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl.

[0224] In another preferred embodiment of the invention, the LC medium comprises one or more compounds of formula III-4 to III-6, preferably formula III-5.

[0225]

[0226] The parameters have the meanings given above, R 11 Preferably, it represents straight-chain alkyl and R 12 Preferably, alkoxy groups are used, each having 1-7 carbon atoms.

[0227] In another preferred embodiment, the LC medium comprises one or more compounds of formula III selected from formulas III-7 to III-9, preferably formula III-8.

[0228]

[0229] The parameters have the meanings given above, R 11 Preferably, it represents straight-chain alkyl and R 12 Preferably, alkoxy groups are used, each having 1-7 carbon atoms.

[0230] In a preferred embodiment, the medium comprises one or more compounds of formula IV.

[0231]

[0232] in

[0233] R 41 This indicates an unsubstituted alkyl group having 1-7 carbon atoms or an unsubstituted alkenyl group having 2-7 carbon atoms, preferably an n-alkyl group, and particularly preferably having 2, 3, 4 or 5 carbon atoms.

[0234] R 42The term refers to an unsubstituted alkyl group having 1-7 carbon atoms or an unsubstituted alkoxy group having 1-6 carbon atoms (preferably having 2-5 carbon atoms), an unsubstituted alkenyl group having 2-7 carbon atoms, preferably having 2, 3 or 4 carbon atoms, more preferably vinyl or 1-propenyl and especially vinyl.

[0235] Compounds of formula IV are preferably selected from formulas IV-1 to IV-6.

[0236]

[0237]

[0238] in

[0239] “alkyl” and “alkyl” * "Each of the above can be independently represented as an alkyl group having 1-7 carbon atoms, preferably having 2-5 carbon atoms."

[0240] "alkenyl" indicates an alkenyl group having 2-5 carbon atoms, preferably 2-4 carbon atoms, and particularly preferably 2 carbon atoms.

[0241] alkenyl * "" indicates an alkenyl group having 2-5 carbon atoms, preferably 2-4 carbon atoms, particularly preferably 2-3 carbon atoms, and

[0242] “alkoxy” refers to an alkoxy group having 1-5 carbon atoms, preferably having 2-4 carbon atoms.

[0243] Preferably, the LC medium comprises one or more compounds selected from formulas IV-1-1 to IV-1-9.

[0244]

[0245]

[0246] Among them, propyl, butyl, and pentyl are straight-chain groups.

[0247] Most preferably, the LC medium of the present invention comprises one or more compounds of formula IV-2-1 and / or IV-2-2.

[0248]

[0249]

[0250] Most preferably, the LC medium of the present invention comprises a compound of formula IV-3, particularly compounds selected from formulas IV-3-1 to IV-3-4.

[0251]

[0252] Most preferably, the LC medium of the present invention comprises a compound of formula IV-4, particularly compounds selected from formulas IV-4-1 and IV-4-2.

[0253]

[0254] LC media preferably additionally contain one or more compounds of formula IVa.

[0255]

[0256] in

[0257] R 41 and R 42 Each of these independently represents a straight-chain alkyl, alkoxy, alkenyl, alkoxyalkyl, or alkoxy group having a maximum of 12 carbon atoms.

[0258] express

[0259] Z 4 It represents a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -C4H8-, or -CF=CF-.

[0260] Preferred compounds of formula IVa are shown below:

[0261]

[0262] Among them alkyl and alkyl * Each of these terms independently represents a straight-chain alkyl group having 1-6 carbon atoms.

[0263] The LC medium of the present invention preferably contains at least one compound of formula IVa-1 and / or formula IVa-2.

[0264] The proportion of the IVa compound in the entire mixture is preferably at least 5 wt%.

[0265] Preferably, the LC medium comprises one or more compounds of formula IVb-1 to IVb-3.

[0266]

[0267]

[0268] in

[0269] “alkyl” and “alkyl” *"Each independently represents a straight-chain alkyl group having 1-6 carbon atoms, and..."

[0270] “alkenyl” and “alkenyl” * Each of them independently represents a straight-chain alkenyl group having 2-6 C atoms.

[0271] The proportion of biphenyls of formula IV-1 to IV-3 in the entire mixture is preferably at least 3 wt%, and particularly ≥5 wt%.

[0272] Of the compounds of formulas IVb-1 to IVb-3, compound IVb-2 is particularly preferred.

[0273] The preferred biphenyl is

[0274]

[0275] Among them, "alkyl" * "" indicates an alkyl group having 1-6 carbon atoms, and preferably n-propyl.

[0276] The LC media of the present invention particularly preferably contain one or more compounds of the formula IVb-1-1 and / or IVb-2-3.

[0277] In a preferred embodiment, the LC medium comprises one or more compounds of formula V.

[0278]

[0279] in

[0280] R 51 and R 52 They are independent of each other for R 41 and R 42 The term "alkyl" is given in one of the following meanings and is preferably interpreted as having 1-7 carbon atoms, preferably n-alkyl, particularly preferably n-alkyl having 1-5 carbon atoms; alkoxy having 1-7 carbon atoms, preferably n-alkoxy, particularly preferably n-alkoxy having 2-5 carbon atoms; or alkoxyalkyl, alkenyl, or alkenyloxy having 2-7 carbon atoms, preferably having 2-4 carbon atoms, preferably alkenyloxy.

[0281] Same or different

[0282]

[0283] in

[0284] Preferred representation

[0285] Z 51Z 52 Each of these independently represents -CH2-CH2-, -CH2-O-, -CH=CH-, -C≡C-, -COO-, or a single bond, preferably -CH2-CH2-, -CH2-O-, or a single bond, and particularly preferably a single bond.

[0286] n is 1 or 2.

[0287] Compounds of formula V are preferably selected from compounds of formulas V-1 to V-16:

[0288]

[0289]

[0290]

[0291] Where R 1 and R 2 Having the above for R 2A The meaning stated.

[0292] R 1 and R 2 Preferably, each represents a straight-chain alkyl or alkenyl group independently of the other.

[0293] Preferred LC media comprise one or more compounds of formulas V-1, V-3, V-4, V-6, V-7, V-10, V-11, V-12, V-14, V-15 and / or V-16.

[0294] The LC media of the present invention particularly preferably contain compounds of formula V-10, V-12, V-16 and / or IV-1, especially in amounts of 5-30%.

[0295] Preferred compounds of formula V-10 are shown below:

[0296]

[0297] The LC medium of the present invention particularly preferably comprises a combination of a tricyclic compound of formula V-10a and / or formula V-10b and one or more bicyclic compounds of formula IV-1. The total proportion of the combination of the compound of formula V-10a and / or V-10b and one or more compounds selected from the dicyclohexyl compound of formula IV-1 is 5-40%, very particularly preferably 15-35%.

[0298] The most particularly preferred LC media contain compounds V-10a and CC-2-3.

[0299]

[0300] Compounds V-10a and IV-1-1 are preferably present in these LC media at a concentration of 15-35%, particularly preferably 15-25% and especially preferably 18-22%, based on the entire mixture.

[0301] Further particularly preferred LC media comprise compounds V-10b and IV-1-1:

[0302]

[0303] Compounds V-10b and IV-1-1 are preferably present in these LC media at a concentration of 15-35%, particularly preferably 15-25% and especially preferably 18-22%, based on the entire mixture.

[0304] Further preferred LC media contain the following three compounds:

[0305]

[0306]

[0307] Compounds V-10a, V-10b and IV-1-1 are preferably present in these LC media at a concentration of 15-35%, particularly preferably 15-25% and especially preferably 18-22%, based on the entire mixture.

[0308] Preferred LC media contain at least one compound selected from the following formula

[0309]

[0310] Where R 41 and R 42 and R 51 and R 52 It has the meaning described above. Preferably, in compounds V-6, V-7, and IV-1, R 41 and R 51 This indicates an alkyl or alkenyl group having 1-6 carbon atoms or 2-6 carbon atoms, and R 42 and R 52 This indicates an alkenyl group having 2-6 carbon atoms.

[0311] 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:

[0312]

[0313]

[0314] Where alkyl represents an alkyl group having 1-6 carbon atoms and alkenyl represents an alkenyl group having 2-6 carbon atoms.

[0315] Compounds of formulas V-6a, V-6b, V-7a, V-7b, IV-4-1, IV-4-2, IV-3a, and IV-3b are preferably present in the LC medium of the present invention in an amount of 1-40 wt%, preferably 5-35 wt%, and very particularly preferably 10-30 wt%.

[0316] In a preferred embodiment of the invention, the LC medium additionally comprises one or more compounds of formulas VI-1 to VI-9.

[0317]

[0318]

[0319] in

[0320] R 7 Each has its own independent property regarding R in Equation IIA 2A One of the meanings, and

[0321] w and x each represent 1-6 independently.

[0322] Particularly preferred is that the LC medium contains at least one compound of formula V-9.

[0323] In a preferred embodiment of the invention, the LC medium further comprises one or more compounds selected from formulas VII-1 to VII-25.

[0324]

[0325]

[0326]

[0327]

[0328] in

[0329] R represents a straight-chain alkyl or alkoxy group with 1-6 carbon atoms, (O) represents -O- or a single bond, X represents F, Cl, OCF3 or OCHF2, and L represents... x It represents H or F, where m is 0, 1, 2, 3, 4, 5 or 6 and n is 0, 1, 2, 3 or 4.

[0330] R preferably represents methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, or pentoxy.

[0331] X preferably represents F or OCH3, with F being the most preferred.

[0332] The LC medium of the present invention preferably contains terphenyl of formulas VII-1 to VII-25 in an amount of 2-30 wt%, particularly 5-20 wt%.

[0333] Particularly preferred are compounds of 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 1-5 carbon atoms. In compound VII-20, R preferably represents an alkyl or alkenyl group, particularly an alkyl group. In compound VII-21, R preferably represents an alkyl group. In compounds VII-22 to VII-25, X preferably represents F.

[0334] If the Δn value of the mixture is ≥0.1, then terphenyl compounds of formulas VII-1 to VII-25 are preferably used in the LC medium of the present invention. The preferred LC medium contains 2-20 wt% of one or more terphenyl compounds selected from formulas VII-1 to VII-25.

[0335] Further preferred implementation schemes are listed below:

[0336] a) The LC medium contains at least one compound selected from formulas Z-1 to Z-14.

[0337]

[0338]

[0339] R, (O) and alkyl have the meanings described above for Formula III.

[0340] b) Preferably, the LC medium of the present invention comprises one or more substances containing tetrahydronaphthyl or naphthyl units, such as compounds of formula N-1 to N-5.

[0341]

[0342] Where R 1N and R 2N Each independently possesses the above-mentioned characteristics for R. 2A The meaning of the above preferably refers to a straight-chain alkyl, a straight-chain alkoxy, or a straight-chain alkenyl group, and

[0343] Z 1 and Z 2Each of these can be represented independently as -C2H4-, -CH=CH-, -(CH2)4-, -(CH2)3O-, -O(CH2)3-, -CH=CHCH2CH2-, -CH2CH2CH=CH-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF-, -CF=CH-, -CH=CF-, -CF2O-, -OCF2-, -CH2-, or a single bond.

[0344] c) Preferred LC media comprise one or more compounds selected from those of formula BC difluorodibenzo-p-chloro, formula CR chloro, and formulas PH-1 and PH-2 fluorophenanthrene compounds.

[0345]

[0346] in

[0347] R B1 ,R B2 ,R CR1 ,R CR2 ,R 1 ,R 2 Each has its own R independently 2A Meaning. c can be 0, 1, or 2. R 1 and R 2 Preferably, alkyl or alkoxy groups having 1-6 carbon atoms are represented independently of each other.

[0348] The LC medium of the present invention preferably contains compounds of formula BC, CR, PH-1, and PH-2 in an amount of 3-20 wt%, particularly in an amount of 3-15 wt%.

[0349] Particularly preferred compounds of formulas BC and CR are compounds BC-1 to BC-7 and CR-1 to CR-5.

[0350]

[0351]

[0352]

[0353] in

[0354] “alkyl” and “alkyl” * "Each independently represents a straight-chain alkyl group having 1-6 carbon atoms, and..."

[0355] “alkenyl” and “alkenyl” * Each of them independently represents a straight-chain alkenyl group having 2-6 C atoms.

[0356] It is particularly preferred that the LC medium contains one, two or three compounds of the form BC-2, BF-1 and / or BF-2.

[0357] d) Preferred LC media contain one or more Ininium compounds.

[0358]

[0359] in

[0360] R 11 ,R 12 ,R 13 Each of these terms independently represents a straight-chain alkyl, alkoxy, alkoxyalkyl, or alkenyl group having 1-6 carbon atoms.

[0361] R 12 and R 13 Additional indication: halogen, preferably F.

[0362] express

[0363]

[0364] i represents 0, 1, or 2.

[0365] Preferred In compounds are those of formulas In-1 to In-16 as described below:

[0366]

[0367]

[0368]

[0369] Compounds of formulas In-1, In-2, In-3 and In-4 are particularly preferred.

[0370] Compounds of formula In and sub-formulas In-1 to In-16 are preferably used in the LC media of the present invention at a concentration of ≥5 wt%, particularly 5-30 wt% and very particularly preferably 5-25 wt%.

[0371] e) Preferred LC media additionally contain one or more compounds of formula L-1 to L-5.

[0372]

[0373] in

[0374] R and R 1 Each of them independently possesses the above-mentioned characteristics for R in Equation IIA. 2AThe meanings are as follows: alkyl indicates an alkyl group having 1-6 carbon atoms. The parameter s indicates 1 or 2.

[0375] Compounds of formulas L-1 to L-5 are preferably used at a concentration of 5-50 wt%, particularly 5-40 wt%, and very particularly preferably 10-40 wt%.

[0376] f) The preferred LC medium further comprises one or more compounds of formula IIA-Y.

[0377]

[0378] Where R 11 and R 12 Having the above for R in Equation IIA 2A One of the given meanings, and L 1 and L 2 F or Cl can be represented in the same or different ways.

[0379] Preferred compounds of formula IIA-Y are selected from the following sub-formulas.

[0380]

[0381]

[0382] Among them, Alkyl and Alkyl * Each of these terms independently represents a straight-chain alkyl group having 1-6 carbon atoms; Alkoxy represents a straight-chain alkoxy group having 1-6 carbon atoms; Alkenyl and Alkenyl * Each of these characters independently represents a straight-chain alkenyl group with 2-6 carbon atoms, and O represents an oxygen atom or a single bond. Alkenyl and Alkenyl * The preferred representations are CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH-, or CH3-CH=CH-(CH2)2-.

[0383] The particularly preferred compounds of formula IIA-Y are selected from the following sub-formulas:

[0384]

[0385] Alkoxy and Alkoxy * It has the meaning defined above and preferably represents methoxy, ethoxy, n-propoxy, n-butoxy or n-pentoxy.

[0386] g) An LC medium additionally comprising one or more compounds selected from the following tetraphenyl compounds:

[0387]

[0388] in

[0389] R Q It is an alkyl, alkoxy, oxalyl, or alkoxyalkyl group having 1-9 carbon atoms, or an alkenyl or alkenoxy group having 2-9 carbon atoms, all of which may optionally be fluorinated.

[0390] X Q It is F, Cl, a haloalkyl or alkoxy group having 1-6 carbon atoms, or a haloalkenyl or alkenoxy group having 2-6 carbon atoms.

[0391] L Q1 -L Q6 Each is independently H or F, where L Q1 -L Q6 At least one of them is F.

[0392] The preferred compound of formula Q is wherein R Q Those that represent straight-chain alkyl groups having 2-6 C- atoms are very preferred, with ethyl, n-propyl or n-butyl being the most preferred.

[0393] The preferred compound of formula Q is wherein L Q3 and L Q4 Those that are F. A further preferred formula Q compound is one in which L... Q3 L Q4 and L Q1 and L Q2 Those whose one or two are F.

[0394] The preferred compound of formula Q is wherein X Q For those representing F or OCF3, F is highly preferred.

[0395] Compound Q is preferably selected from the following sub-formulas

[0396]

[0397] Where R Q It has one of the meanings of formula Q or one of its preferred meanings given in the context, and preferably ethyl, n-propyl or n-butyl.

[0398] The preferred compound is of formula Q1, especially R. Q Those that are n-propyl.

[0399] Preferably, the proportion of compound Q in the LC main mixture is >0 to ≤5 wt%, very preferably 0.05-2 wt%, more preferably 0.1-1 wt%, and most preferably 0.1-0.8 wt%.

[0400] The preferred LC medium contains 1-5 compounds, preferably 1 or 2 compounds of formula Q.

[0401] Adding a Q-type tetraphenyl compound to the LC host mixture can reduce ODF inhomogeneity while maintaining high UV absorption, enabling rapid and complete polymerization, producing a strong and fast tilt angle, and improving the UV stability of the LC medium.

[0402] Furthermore, adding a Q-type compound with positive dielectric anisotropy to an LC dielectric with negative dielectric anisotropy allows for better control of the dielectric constant ε. || and ε ⊥ The value of ε can be achieved, especially high dielectric constant ε. || The value of is adjusted, and the dielectric anisotropy Δε is kept constant, thereby reducing the recoil voltage and reducing image stickiness.

[0403] The LC medium of the present invention preferably includes

[0404] - One or more compounds of formula I or its sub-formulas, preferably with a total concentration of 0.001%-0.02%, more preferably 0.002%-0.015%, and most preferably 0.005%-0.015%.

[0405] and / or

[0406] - One or more compounds of formula IIA, preferably with a total concentration of 5%-30%, more preferably 7%-25%, and particularly preferably 10%-20%;

[0407] and / or

[0408] - One or more compounds of formula IIA and IIB, preferably with a total concentration of 30%-45%;

[0409] and / or

[0410] - One or more Formula IV compounds, preferably with a total concentration of 35%-70%, more preferably 40%-65%, and particularly preferably 45%-60%;

[0411] and / or

[0412] - One or more compounds of formula IV-3, preferably with a total concentration of 35%-60%, more preferably 40%-55%, and particularly preferably 45%-50%;

[0413] and / or

[0414] - One or more compounds of formula III-2, preferably formula III-2-6, preferably with a total concentration of 2%-25%, more preferably 5%-15%, and particularly preferably 5-12%.

[0415] In particular, the medium contains

[0416] - One or more compounds CY-n-Om, particularly CY-3-O4, CY-5-O4 and / or CY-3-O2, preferably with a total concentration of 5%-30%, more preferably 10%-20%;

[0417] and / or

[0418] - One or more compounds PY-n-Om, particularly PY-3-O2 and / or PY-1-O2, preferably with a total concentration of 5%-30%, more preferably 5%-20%;

[0419] and / or

[0420] -CPY-n-Om, particularly CPY-2-O2, CPY-3-O2 and / or CPY-5-O2, preferably with a total concentration >5%, particularly 7%-20%, based on the entire mixture.

[0421] and / or

[0422] - 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 with a total concentration of >3%, particularly 5-15%, based on the entire mixture;

[0423] and / or

[0424] - One or more compounds CPY-n-Om, preferably CPY-2-O2 and / or CPY-3-O2, preferably with a total concentration of >3%, particularly 5-15%, based on the entire mixture;

[0425] and / or

[0426] -CLY-n-Om, preferably CLY-2-O4, CLY-3-O2 and / or CLY-3-O3, preferably with a total concentration >5%, particularly 10-30%, very preferably 15-20%, based on the entire mixture;

[0427] and / or

[0428] -CPY-n-Om and CY-n-Om, preferably with a total concentration of 10-80%, based on the entire mixture.

[0429] and / or

[0430] -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 with a total concentration of 5-20%, more preferably 10-15%, based on the entire mixture.

[0431] and / or

[0432] -CC-3-V, preferably with a total concentration of 5-50%, based on the entire mixture.

[0433] and / or

[0434] The compound of formula CC-3-V1 has a total concentration of 5-40%, more preferably 15%-35%, and particularly preferably 20%-30%.

[0435] and / or

[0436] - One or more compounds of the formula B-nO-Om and / or B(S)-nO-Om, particularly compounds B(S)-2O-O4 and / or B(S)-2O-O5, preferably at a concentration of 2-12%.

[0437] and / or

[0438] -0.1% to 3% of the compound PPGU-3-F,

[0439] and / or

[0440] -Compound B(S)-(c5)1O-O2:

[0441]

[0442] The present invention further relates to an active matrix addressing electro-optic display, characterized in that it contains a liquid crystal medium as claimed in claim 1 as a dielectric, and wherein the display is a 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 SA-FFS display.

[0443] Advantageous for the liquid crystal medium of the present invention is that it preferably has a nematic phase with a temperature of ≤-20°C to ≥70°C, particularly preferably ≤-30°C to ≥80°C, and very particularly preferably ≤-40°C to ≥90°C.

[0444] The medium of the present invention preferably has a clearing temperature of 70°C or higher, and very preferably 74°C or higher.

[0445] The LC medium preferably has a nematic LC phase.

[0446] The phrase "possessing a nematic phase" here means, on the one hand, that no smectic phase or crystallization was observed at the corresponding temperature at low temperatures, and on the other hand, that the nematic phase did not become clear upon heating. Low-temperature studies were conducted in a flow viscometer at the corresponding temperature and verified by storing the medium in a test chamber with a layer thickness corresponding to the electro-optic application for at least 100 hours. If the storage stability in the corresponding test chamber at -20°C is 1000 hours or more, the medium is said to be stable at that temperature. At -30°C and -40°C, the corresponding times are 500 hours and 250 hours, respectively. At high temperatures, the clearing point is measured in a capillary using conventional methods.

[0447] The liquid crystal mixture preferably has a nematic phase range of at least 60K and a maximum thickness of 30mm at 20°C. 2 ·s -1 Flow viscosity ν 20 .

[0448] The mixture is nematic at -20°C or lower, preferably -30°C or lower, and very preferably -40°C or lower.

[0449] The birefringence Δn value in the liquid crystal mixture is typically 0.07-0.16, preferably 0.08-0.15, and most preferably 0.09-0.14.

[0450] In a preferred embodiment of the invention, the birefringence of the medium is 0.090-0.110, preferably 0.095-0.105, and particularly 0.100-0.105.

[0451] In another preferred embodiment, the medium of the present invention has a birefringence of 0.120 or higher, preferably 0.125-0.145, more preferably 0.130-0.140.

[0452] The liquid crystal mixture of the present invention has a dielectric anisotropy Δε of -1.5 to -8.0, preferably -2.0 to -4.0, and particularly -2.5 to -3.5.

[0453] The rotational viscosity γ1 at 20°C is preferably ≤120 mPa·s, and especially ≤100 mPa·s.

[0454] In a preferred embodiment, the rotational viscosity γ1 at 20°C is ≤100 mPa·s, particularly ≤95 mPa·s.

[0455] The liquid crystal media of the present invention have relatively low threshold voltages (V0). They are preferably from 1.7V to 3.0V, particularly preferably ≤2.7V and very particularly preferably ≤2.5V.

[0456] For the purposes of this invention, unless otherwise explicitly stated, the term “threshold voltage” refers to the capacitive threshold (V0), also known as the Freedericks threshold.

[0457] Furthermore, the liquid crystal medium of the present invention has a high voltage retention rate in the liquid crystal cell.

[0458] Typically, liquid crystal media with low addressing voltage or threshold voltage exhibit lower voltage retention than those with higher addressing voltage or threshold voltage, and vice versa.

[0459] For the purposes of this invention, the term "dielectrically positive compound" refers to a compound having Δε > 1.5, the term "dielectrically neutral compound" refers to those having -1.5 ≤ Δε ≤ 1.5, and the term "dielectrically negative compound" refers to those having Δε < -1.5. Here, the dielectric anisotropy of the compound is determined by dissolving 10% of the compound in a liquid crystal body in at least one test cell and measuring the capacitance of the resulting mixture. In each case, the test cell has a layer thickness of 20 μm and has vertical and surface alignment at 1 kHz. The measurement voltage is typically 0.5 V–1.0 V, but is always below the capacitance threshold of each liquid crystal mixture studied.

[0460] All temperature values ​​described in this invention are in °C.

[0461] The LC dielectric of this invention is suitable for all VA-TFT (vertically aligned thin-film transistor) applications, such as VAN (vertically aligned nematic), MVA (multi-domain VA), (S)-PVA (super-patterned VA), ASV (advanced super-view or axisymmetric VA), or UV. 2 A. In addition, they are also suitable for IPS (in-plane switching) and FFS (edge ​​field switching) applications with negative Δε.

[0462] The nematic LC media in the display of the present invention typically comprises two components, NA and NB, which are themselves composed of one or more separate compounds.

[0463] Component NA exhibits significant negative dielectric anisotropy, and makes the dielectric anisotropy of the nematic phase ≤-0.5. In addition to one or more compounds of formula I, it preferably includes compounds of formula IIA, IIB, and / or IIC, as well as one or more compounds of formula IV-1.

[0464] The proportion of component NA is preferably 45-100%, particularly 60-85%.

[0465] For component NA, it is preferable to select one or more individual compounds with a value of Δε ≤ -0.8. The smaller the proportion of NA in the entire mixture, the more negative this value will be.

[0466] Component NB exhibits significant nematogeneity, and its flow viscosity at 20°C is no greater than 30 mm. 2 ·s -1 Preferably no larger than 25mm 2 ·s -1 .

[0467] The most preferred single compound in component NB is a nematic liquid crystal with extremely low viscosity, having a flow viscosity of no more than 18 mm at 20°C. 2 ·s -1 Preferably no larger than 12mm 2 ·s -1 .

[0468] Component NB is a monotropically or enantiotropically nematic, lacks a smectic phase, and can prevent the formation of a smectic phase in LC media at very low temperatures. For example, if various high-nematic materials are added to a smectic liquid crystal mixture, the nematic states of these materials can be compared by suppressing the degree to which a smectic phase is formed.

[0469] The mixture may also optionally contain component NC, which comprises compounds having a dielectric anisotropy of Δε ≥ 1.5. These so-called positive compounds are typically present in the mixture of negative dielectric anisotropy in an amount of ≤ 20 wt%, based on the whole mixture.

[0470] In addition to one or more compounds of formula I or its sub-formulas, the medium preferably contains 4-15, particularly 5-12, and especially preferably <10 compounds of formula IIA, IIB and / or IIC and optionally one or more compounds of formula IV-1.

[0471] In addition to compounds of formula I or its sub-formulas and compounds of formulas IIA, IIB and / or IIC and optional IV-1, other components may also be present in an amount of up to 45% of the total mixture, but preferably up to 35%, and particularly up to 10%.

[0472] Other components are preferably selected from nematogenic substances, particularly from known substances of the following classes: azobenzene, benzenemethylaniline, biphenyl, terphenyl, phenyl benzoate or cyclohexyl benzoate, phenyl cyclohexanecarboxylate or cyclohexanecarboxylate, phenylcyclohexane, cyclohexylbiphenyl, cyclohexylcyclohexane, cyclohexylnaphthalene, 1,4-bicyclohexylbiphenyl or cyclohexylpyrimidine, phenyl dioxane or cyclohexyldioxane, optionally halogenated stilbene, benzylphenyl ether, diphenylacetylene, and substituted cinnamates.

[0473] The most important compounds suitable as components of this type of liquid crystal phase can be characterized by the following formula IV.

[0474] R 20 -LGER 21 IV

[0475] Where L and E each refer to carbocyclic or heterocyclic systems derived from the following groups: 1,4-disubstituted benzene rings and cyclohexane rings; 4,4'-disubstituted biphenyl, phenylcyclohexane, and cyclohexylcyclohexane systems; 2,5-disubstituted pyrimidine and 1,3-dioxane rings; 2,6-disubstituted naphthalene, dihydronaphthalene, and tetrahydronaphthalene; quinazoline and tetrahydroquinazoline.

[0476] G represents -CH=CH- -N(O)=N-

[0477] -CH=CQ- -CH=N(O)-

[0478] -C≡C- -CH2-CH2-

[0479] -CO-O- -CH2-O-

[0480] -CO-S- -CH2-S-

[0481] -CH=N- -COO-Phe-COO-

[0482] -CF2O- -CF=CF-

[0483] -OCF2- -OCH2-

[0484] -(CH2)4- -(CH2)3O-

[0485] Or a CC single bond, Q refers to halogen, preferably chlorine or -CN, and R 20 and R 21 Each refers to an alkyl, alkenyl, alkoxy, alkoxyalkyl or alkoxycarbonyl group having up to 18, preferably up to 8, carbon atoms, or one of these groups refers to CN, NC, NO2, NCS, CF3, SF5, OCF3, F, Cl or Br.

[0486] In most of these compounds, R 20 and R 21 These substances differ from one another; one of these groups is typically alkyl or alkoxy. Other variations of the proposed substituents are also common. Many such substances, or mixtures thereof, are commercially available. All of these substances can be prepared by methods known from the literature.

[0487] It will be self-evident to those skilled in the art that the VA, IPS or FFS mixtures according to the present invention may also contain compounds in which, for example, H, N, O, Cl and F are substituted with corresponding isotopes.

[0488] The combination of the compounds of the preferred embodiments mentioned above with the aforementioned polymeric compounds results in a low threshold voltage, low rotational viscosity, and very good low-temperature stability in the LC medium of the present invention, while maintaining high-definition bright spots and high HR values, and allowing for the rapid establishment of particularly low tilt angles (i.e., large tilt angles) in PSA displays. In particular, compared with LC media from the prior art, this LC medium exhibits a significantly shorter response time in PSA displays, especially grayscale response time.

[0489] The present invention also relates to an LC display comprising an LC medium as described in the context.

[0490] The LC display is preferably VA, IPS, FFS, UB-FFS or UV. 2 Monitor A.

[0491] As described in the prior art cited at the outset, the structure of the display of the present invention corresponds to the typical geometry of a PSA display. Preferred geometries are those without protrusions, particularly those where the electrodes on the color filter side are unstructured and only the electrodes on the TFT side have slots. For example, a particularly suitable and preferred electrode structure for a PS-VA display is described in US2006 / 0066793A1.

[0492] The preferred LC display of the present invention includes:

[0493] - A first substrate, comprising a pixel electrode defining a pixel region, the pixel electrode being connected to a switching element disposed in each pixel region and optionally including a microslit pattern, and a first alignment layer optionally disposed on the pixel electrode.

[0494] - A second substrate, comprising a common electrode layer disposed on the entire portion of the second substrate facing the first substrate, and an optional second alignment layer.

[0495] - An LC layer disposed between a first substrate and a second substrate and including an LC medium as described in the context.

[0496] The first and / or second alignment layers control the alignment orientation of the LC molecules in the LC layer. For example, in VA displays, the alignment layers are selected to impart vertical (or perpendicular) alignment (i.e., perpendicular to the surface) or tilted alignment to the LC molecules. Such alignment layers may, for example, contain polyimide, which can also be rubbed or prepared by photoalignment methods. In UV... 2In display A, the alignment layer is made by photopolymerization using linearly polarized UV light irradiated at an angle.

[0497] An LC layer with an LC dielectric can be deposited between the substrates of a display using methods commonly used by display manufacturers, such as the so-called one-drop-filling (ODF) method.

[0498] LC displays may include other components such as color filters, black matrices, passivation layers, optical delay layers, transistor elements for addressing individual pixels, etc., which are well known to those skilled in the art and can be used without inventive skills.

[0499] Electrode structures can be designed by engineers according to the specific display type. For example, for VA displays, multi-domain orientation of LC molecules can be induced by providing electrodes with slits and / or protrusions or bumps to produce two, four, or more different tilt alignment directions.

[0500] In addition to the compound of formula I, the LC medium may also contain one or more other stabilizers. Suitable types and amounts of stabilizers are known to those skilled in the art and are described in the literature. Particularly suitable, for example, Ciba AG series of commercially available stabilizers, such as 1076. If stabilizers are used, their proportion is preferably 10-5000 ppm, particularly preferably 50-500 ppm.

[0501] In a preferred embodiment, the LC medium contains one or more chiral dopants, preferably at a concentration of 0.01-1 wt%, very preferably 0.05-1.0 wt%. The chiral dopants are preferably selected from compounds in Table B below, and very preferably R- or S-1011, R- or S-2011, R- or S-3011, R- or S-4011 and R- or S-5011.

[0502] In another preferred embodiment, the LC medium contains a racemic form of one or more chiral dopants, preferably selected from the chiral dopants mentioned in the previous paragraph.

[0503] In addition, 0 to 15% by weight of a pleochroic dye, nanoparticles, conductive salts, preferably ammonium ethyl dimethyl dodecyl 4-hexyloxybenzoate, ammonium tetrabutyltetraphenylborate, or complex salts of crown ethers can be added to the LC medium (see, for example, Haller et al., Mol. Cryst. Liq. Cryst.). 24, 249-258 (1973)) are used to improve conductivity, or to add substances to modify the dielectric anisotropy, viscosity and / or orientation of the nematic phase. Such substances are described, for example, in DE-A 22 09 127, 2240 864, 23 21 632, 23 38 281, 24 50 088, 26 37 430 and 28 53 728.

[0504] The individual components of the preferred embodiments of the LC media listed above according to the invention are known, or the methods for preparing them can be obtained from the prior art by those skilled in the art, as they are based on standard methods described in the literature. For example, corresponding compounds of formula CY are described in EP-A-0 364 538. For example, corresponding compounds of formula ZK are described in DE-A-26 36 684 and DE-A-33 21 373.

[0505] The LC media used according to the invention can be prepared by conventional methods, for example by mixing one or more of the compounds mentioned above with one or more compounds of Formula I as defined above, and optionally with other liquid crystal compounds and / or additives. Typically, a desired amount of the component used in a small quantity is dissolved in the component constituting the main component, which is advantageously carried out at elevated temperatures. The solution of the components can also be mixed in an organic solvent such as acetone, chloroform, or methanol, and the solvent is removed again, for example by distillation after thorough mixing. The invention also relates to a method for preparing the LC media according to the invention.

[0506] It will be self-evident to those skilled in the art that the LC medium according to the present invention may also contain, for example, compounds in which H, N, O, Cl, and F are replaced by corresponding isotopes such as deuterium.

[0507] The following examples illustrate the invention but do not limit it. However, they demonstrate to those skilled in the art the preferred mixture concept, the preferred compounds used and their respective concentrations, and combinations thereof. Furthermore, the examples clarify which properties and combinations of properties are available.

[0508] Preferred mixture components are shown in Table A below.

[0509] Table A

[0510] In Table A, m and n are independent integers from 1 to 12, preferably 1, 2, 3, 4, 5, or 6, k is 0, 1, 2, 3, 4, 5, or 6, and (O)C m H 2m+1 Indicate C m H 2m+1 or OC mH 2m+1 。

[0511]

[0512]

[0513]

[0514]

[0515]

[0516]

[0517]

[0518]

[0519]

[0520]

[0521]

[0522]

[0523]

[0524]

[0525]

[0526]

[0527]

[0528]

[0529]

[0530]

[0531]

[0532]

[0533]

[0534]

[0535] In a preferred embodiment of the present invention, the LC medium of the present invention comprises one or more compounds selected from the compounds in Table A.

[0536] Table B

[0537] Table B shows the chiral dopants that can be added to the LC media of this invention.

[0538]

[0539]

[0540] The LC dielectric preferably contains 0-10 wt%, particularly 0.01-5 wt%, and especially preferably 0.1-3 wt% of dopant. The LC dielectric preferably contains one or more dopants selected from the compounds in Table B.

[0541] Table C

[0542] Table C shows possible stabilizers that can be added to the LC media of the present invention. Here, n represents an integer from 1 to 12, preferably 1, 2, 3, 4, 5, 6, 7 or 8, and the terminal methyl group is not shown.

[0543]

[0544]

[0545]

[0546]

[0547]

[0548]

[0549]

[0550] The LC medium preferably contains 0-10 wt%, particularly 1 ppm-5 wt%, and especially preferably 1 ppm-1 wt% of a stabilizer. The LC medium preferably contains one or more stabilizers selected from the compounds in Table C. Example

[0551] The following examples illustrate the invention but do not limit it. However, they demonstrate to those skilled in the art the concept of preferred mixtures and the preferred compounds used, their corresponding concentrations, and combinations thereof. Furthermore, the examples illustrate the available properties and combinations of properties.

[0552] In addition, the following abbreviations and symbols were used:

[0553] V0 represents the threshold voltage at 20℃, capacitive [V].

[0554] n e This indicates the unusual refractive index at 20°C and 589 nm.

[0555] n o This represents the ordinary refractive index at 20°C and 589 nm.

[0556] Δn represents the optical anisotropy at 20℃ and 589nm.

[0557] ε ⊥ This represents the dielectric constant perpendicular to the director at 20℃ and 1kHz.

[0558] ε || This represents the dielectric constant parallel to the director at 20℃ and 1kHz.

[0559] Δε represents the dielectric anisotropy at 20℃ and 1kHz.

[0560] cl.p., T(N,I) represents the clearing point [°C].

[0561] γ1 represents the rotational viscosity [mPa·s] at 20℃.

[0562] K1 represents the elastic constant at 20℃, and the "oblique stretching" deformation [pN].

[0563] K2 represents the elastic constant at 20℃, and the "torsional" deformation [pN].

[0564] K3 represents the elastic constant at 20°C, and the bending deformation [pN].

[0565] Unless otherwise expressly stated, all concentrations in this application are given as weight percentages and refer to the entire mixture in question, which contains all solid or liquid crystal components (without solvent).

[0566] Unless otherwise stated, all temperature values ​​indicated in this application, such as melting point T(C,N), transformation from smectic (S) to nematic (N) T(S,N), and clearing point T(N,I), are expressed in degrees Celsius (°C). Mp represents the melting point, and cl.p. = clearing point. Furthermore, C = liquid crystal phase, N = nematic phase, S = smectic phase, and I = isotropic phase. The data between these symbols represent the transformation temperature.

[0567] All physical properties are and have been determined according to “Merck Liquid Crystals, Physical Properties of Liquid Crystals” Status November 1997, Merck KGaA, Germany, and are applicable to a temperature of 20°C, with Δn measured at 589 nm and Δε measured at 1 kHz, unless otherwise explicitly stated in each case.

[0568] The term "threshold voltage" used in this invention refers to the capacitive threshold (V0), which is also known as the Freedericks threshold, unless otherwise stated. In embodiments, the optical threshold is also, as is generally the case, for 10% relative contrast (V0). 10 (This is given.)

[0569] Unless otherwise stated, the preparation of test kits and the measurement of their electro-optic and other properties shall be carried out by the methods described below or similar methods.

[0570] Unless otherwise stated, 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 LC molecules with uniform orientation, corresponding to the long axis of the molecules in the case of rod-shaped, uniaxial positive birefringent LC molecules.

[0571] Example 1

[0572] The following is a formulation of the nematic LC bulk mixture N1.

[0573]

[0574] The stable mixture S1.1 was prepared by adding 100 ppm of compound M1 according to formula I to the nematic LC host mixture N1.

[0575] The stable mixture S1.2 was prepared by adding 200 ppm of compound M1 according to formula I to the nematic LC host mixture N1.

[0576]

[0577] Comparative Example 1

[0578] Mixture C1 was prepared by adding 300 ppm of compound M1 to the nematic LC host mixture N1.

[0579] Example 2

[0580] The following is a formulation of the nematic LC bulk mixture N2.

[0581]

[0582]

[0583] The stable mixture S2 was prepared by adding 150 ppm of compound M1 to the nematic LC host mixture N2.

[0584] Example 3

[0585] The following is a formulation of the nematic LC bulk mixture N3.

[0586]

[0587] The stable mixture S3 was prepared by adding 100 ppm of compound M1 to the nematic LC host mixture N3.

[0588] Example 4

[0589] The following is a formulation of the nematic LC bulk mixture N4.

[0590]

[0591] The stable mixture S4.1 was prepared by adding 100 ppm of compound M1 to the nematic LC host mixture N4.

[0592] The stable mixture S4.2 was prepared by adding 200 ppm of compound M1 to the nematic LC host mixture N4.

[0593] Example 5

[0594] The following is a formulation of the nematic LC bulk mixture N5.

[0595]

[0596] The stable mixture S5 was prepared by adding 100 ppm of compound M1 to the nematic LC host mixture N5.

[0597] Example 6

[0598] The following is a formulation of the nematic LC bulk mixture N6.

[0599]

[0600] The stable mixture S6 was prepared by adding 150 ppm of compound M1 to the nematic LC host mixture N6.

[0601] Example 7

[0602] The following is a formulation of the nematic LC bulk mixture N7.

[0603]

[0604]

[0605] The stable mixture S7 was prepared by adding 100 ppm of compound M1 to the nematic LC host mixture N7.

[0606] Example 8

[0607] The following is a formulation of the nematic LC bulk mixture N8.

[0608]

[0609] The stable mixture S8 was prepared by adding 150 ppm of compound M1 to the nematic LC host mixture N8.

[0610] Example 9

[0611] The following is a formulation of the nematic LC bulk mixture N9.

[0612]

[0613] The stable mixture S9 was prepared by adding 150 ppm of compound M1 to the nematic LC host mixture N9.

[0614] Example 10

[0615] The following is a formulation of the nematic LC bulk mixture N10.

[0616]

[0617] The stable mixture S10.1 was prepared by adding 100 ppm of compound M1 to the nematic LC host mixture N10.

[0618] The stable mixture S10.2 was prepared by adding 200 ppm of compound M1 to the nematic LC host mixture N10.

[0619] Example 11

[0620] The following is a formulation of the nematic LC bulk mixture N11.

[0621]

[0622] The stable mixture S11 was prepared by adding 100 ppm of compound M1 to the nematic LC host mixture N11.

[0623] Application Examples

[0624] The VHR of stable mixtures S1.1 and S1.2 containing compound M1 according to the present invention was measured relative to the pure main mixture N1.

[0625] VHR measurement

[0626] The test chamber for VHR measurement consists of two parallel glass outer plates spaced 3.2 μm apart. Each glass outer plate has an electrode layer inside and a polyimide alignment layer on top. The two polyimide layers achieve vertical alignment of liquid crystal molecules and apply photo-alignment in a tilt direction that induces the two substrates to cross each other.

[0627] Six test chambers were prepared for each LC mixture. After filling with the LC mixture, the chambers were sealed with a sealant. The VHR of the bulk mixture N1 and mixtures S1.1 and S1.2 was then measured before and after applying BL stress at 60°C for 120 hours, with a voltage of 1V / 0.6Hz applied at 60°C. Light and thermal stress typically lead to the generation of impurities and ions that reduce the VHR in LC mixtures; therefore, the smaller the absolute decrease in VHR value after stress, the better the performance for display applications.

[0628] The results are shown in Table 1.

[0629] Table 1 - VHR

[0630]

[0631] As can be seen from Table 1, for mixtures S1.1 and S1.2 according to the present invention, the initial VHR is already higher than that of the main mixture N1 without compound M1. After 120 h of BL stress, the VHR of the main mixture N1 shows a strong decrease, while the VHR of mixtures S1.1 and S1.2 shows a smaller decrease.

[0632] Inclination angle measurement

[0633] The tilt angle of the stable mixture S1.1 according to the present invention was measured compared to the pure main mixture N1 and the comparative mixture C1 with a higher content of compound M1.

[0634] The test chamber for tilt angle measurement consists of two parallel glass outer plates spaced 3.2 μm apart. Each glass outer plate has an electrode layer inside and a polyimide alignment layer on top. The two polyimide layers achieve vertical alignment of liquid crystal molecules and apply light alignment in the two substrates to induce antiparallel tilt directions.

[0635] The LC mixture was filled into the test chamber and then sealed with a sealant. Before and after exposure to BL and 60Vpp electrical stress for 120h, the tilt angles generated in the main mixture N1 and mixtures S1.1 and C1 were measured using a Mueller matrix polarimeter "AxoScan" from Axometrics.

[0636] The change in tilt angle, i.e. the change in the absolute value of the tilt angle Δtilt after stress, is shown in Table 2 below.

[0637] Table 2 - Tilt Changes

[0638] mixture Δtilt / ° N1 0.77 S1.1 0.72 C1 3.57

[0639] As can be seen from Table 2, mixture S1.1 containing 100 ppm compound M1 according to the present invention exhibits a small tilt angle change similar to that of the main mixture N1, meaning that compound M1 does not produce a significant tilt angle at this concentration. In contrast, the comparative mixture C1 with 300 ppm compound M1 shows a stronger tilt angle change, indicating that a tilt angle has been produced.

[0640] In summary, the results above indicate that when added at low concentrations to nematic host mixtures, compounds of Formula I can increase VHR without exhibiting significant tilt angle generation.

Claims

1. An LC medium containing one or more compounds of formula I at a concentration of 10 to 250 ppm. Each group is independent of the others and, each time it appears, has the same or different meanings as follows: P is an acrylate group or a methacrylate group. Sp 1 Sp 2 Sp 3 It is a spacer group or a single bond, wherein, At least one Sp group is different from a single bond. If Sp is different from a single bond, it is selected from -(CH2)2-, -(CH2)3-, -(CH2)4-, -O-(CH2)2-, -O-(CH2)3-, -O-CO-(CH2)2-, and -CO-O-(CH)2-, wherein the O atom or CO group is attached to the benzene ring. L represents F, Cl, CN, or OCH3, and r and s represent 0, 1, 2, 3, or 4. And further includes one or more compounds of formula II Each group is independent of the others and, each time it appears, has the same or different meanings as follows: R 1 R 2 It is a straight-chain, branched, or cyclic alkyl group having 1-25 carbon atoms, wherein one or more non-adjacent CH2 groups are optionally configured such that the O- and / or S- atoms are not directly connected to each other by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-, -O-CO-O-, CR 0 =CR 00 -、-C≡C-、 Substitution, wherein one or more H atoms are each optionally substituted by F or Cl. A 1 A 2 Groups selected from the following formulas Z 1 Z 2 For -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CO-O-, -O-CO-, -C2F4-, -CF=CF-, -CH=CH-CH2O-, or single bonds. L 1 L 2 L 3 L 4 It can be F, Cl, OCF3, CF3, CH3, CH2F, or CHF2. Y is H, F, Cl, CF3, CHF2, or CH3. L C It is CH3 or OCH3. a1 is 1 or 2. a2 is 0 or 1.

2. The LC medium according to claim 1, characterized in that... Compounds of formula I are selected from the following formulas Wherein P has the meaning of claim 1, L has the meaning of claim 1, and Sp' has one of the meanings of Sp given in claim 1 that is different from that of a single bond.

3. The LC medium according to claim 1 or 2, characterized in that... Compounds of formula I are selected from the following formulas:

4. The LC medium according to claim 1 or 2, characterized in that... It comprises one or more compounds of formula II selected from compounds of formulas IIA, IIB, IIC, and IID. in R 2A and R 2B Each of these groups independently represents H, an alkyl or alkenyl group having up to 15 carbon atoms, which is unsubstituted, monosubstituted with CN or CF3, or at least monosubstituted with a halogen, wherein one or more CH2 groups among these groups can be used such that the O atom is not directly attached to each other by -O-, -S-, Replace with -C≡C-, -CF₂O-, -OCF₂-, -OC-O-, or -O-CO-. L 1 To L 4 Each can be independently represented as F, Cl, CF3, or CHF2. Y represents H, F, Cl, CF3, CHF2, or CH3. Z 2 Z 2B and Z 2D Each of these independently represents a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF-, and -CH=CHCH2O-. p represents 0, 1, or 2, and Each occurrence of q represents either 0 or 1, either the same or different.

5. The LC medium according to claim 1 or 2, characterized in that... It additionally contains one or more compounds of formula III. in R 11 and R 12 Each of these groups independently represents H, an alkyl or alkoxy group having 1-15 carbon atoms, wherein one or more CH2 groups among these groups can be represented independently such that the O atom is not directly connected to each other. -O-, -S-, -C≡C-, -CF₂O-, -OCF₂-, -CH=CH-, -OC-O-, or -O-CO- can be substituted, and in addition, one or more H atoms can be substituted by halogens. A 3 Each occurrence represents an independent representation. a) 1,4-cyclohexeneyl or 1,4-cyclohexeneyl, wherein one or both non-adjacent CH2 groups may be replaced by -O- or -S-. b) 1,4-Phenylidene, wherein one or both CH groups may be replaced by N, or c) A group selected from spiro[3.3]heptane-2,6-diyl, 1,4-bicyclo[2.2.2]octyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl, and fluorene-2,7-diyl. Groups a), b), and c) can be mono- or poly-substituted with halogen atoms. n represents 0, 1, or 2. Z 1 Each occurrence independently represents -CO-O-, -O-CO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -(CH2)4-, -CH=CH-CH2O-, -C2F4-, -CH2CF2-, -CF2CH2-, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C-, or a single bond, and L 11 and L 12 Each of them independently represents H, F, Cl, CF3 or CHF2, and W represents O or S.

6. The LC medium according to claim 1 or 2, characterized in that... It additionally contains one or more compounds of formula IV. in R 41 This indicates an unsubstituted alkyl group having 1-7 carbon atoms or an unsubstituted alkenyl group having 2-7 carbon atoms, and R 42 It indicates an unsubstituted alkyl group having 1-7 carbon atoms, an unsubstituted alkoxy group having 1-6 carbon atoms, or an unsubstituted alkenyl group having 2-7 carbon atoms.

7. The LC medium according to claim 1 or 2, characterized in that... It contains one or more compounds of formula IV-3. in "alkyl" indicates an alkyl group having 1-7 carbon atoms. "alkenyl" refers to an alkenyl group having 2-5 carbon atoms.

8. The LC medium according to claim 1 or 2, characterized in that... It additionally contains one or more compounds of formula V. in R 51 and R 52 They are independent of each other for R 41 and R 42 One of the meanings given is Same or different in Z 51 Z 52 Each of these independently represents -CH2-CH2-, -CH2-O-, -CH=CH-, -C≡C-, -COO-, or a single bond, and n is 1 or 2.

9. The LC medium according to claim 1 or 2, characterized in that... It additionally contains one or more additives selected from stabilizers and chiral dopants.

10. A method for preparing an LC medium according to any one of claims 1-9, comprising the steps of mixing one or more compounds of formula I as defined in any one of claims 1-3 with one or more compounds of formula II, III, IV and / or V as defined in any one of claims 1 to 8, and optionally mixing with other liquid crystal compounds and / or additives.

11. An LC display comprising an LC medium as defined in any one of claims 1-9.

12. The LC display of claim 11, wherein it is a VA, IPS, FFS or UV2A mode display.

13. The LC display according to claim 11 or 12, characterized in that... It comprises two substrates, at least one of which is transparent to light, electrodes disposed on each substrate or two electrodes disposed on only one substrate, and a layer of LC dielectric according to any one of claims 1-9 located between the substrates.

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