TW201602317A - Liquid-crystal medium and liquid-crystal display - Google Patents

Abstract

The present invention relates to LC media, to a process for the preparation thereof, and to the use thereof for optical, electro-optical and electronic purposes, in particular in LC displays, especially in LC displays of the PS (polymer-stabilised) or PSA (polymer-sustained alignment) type.

Description

Liquid crystal medium and liquid crystal display

The present invention relates to LC media; a process for its preparation; for use in optical, electro-optic and electronic purposes, in particular LC displays, in particular PS (polymer stabilization) or PSA (polymer continuous alignment) type LC displays.

Vertical alignment units have been widely used in liquid crystal display (LCD) devices due to their excellent contrast ratio. In normal incidence, the contrast ratio is insensitive to incident light wavelength, LC cell gap, and operating temperature. The LC cell of the VA display contains a layer of liquid crystal (LC) dielectric between the two transparent electrodes, wherein the LC medium typically has a negative dielectric (DC) anisotropy. In the off state, the molecules of the LC layer are aligned perpendicular to the electrode surface (vertically) or have an oblique vertical alignment. After applying a voltage to the electrodes, realignment of LC molecules parallel to the electrode surface occurs.

Further developed is the so-called PS (Polymer Stabilized) display, which is also known by the term "PSA" (polymer continuous alignment). In such displays, a small amount (eg, 0.3% by weight, typically <1% by weight) of the polymerizable compound is added to the LC medium and, after introduction into the LC unit, is typically UV-polymerized by applying a voltage between the electrodes. In situ polymerization or cross-linking. It has proven to be particularly suitable to add a polymerisable liquid crystal primordium or liquid crystal compound (also known as "reactive liquid crystal priming" (RM)) to the LC mixture. At the same time, the PSA principle is being used in different classic LC displays. Thus, for example, PSA-VA, PSA-OCB, PS-IPS/FFS, and PS-TN displays are known.

PSA-VA displays are described, for example, in JP 10-036847 A, EP 1 170 626 A2, EP 1 378 557 A1, EP 1 498 468 A1, US 2004/0191428 A1, US 2006/0066793 A1 and US 2006/0103804 A1. PSA-OCB displays are described, for example, in T.-J-Chen et al, Jpn. J. Appl. Phys. 45, 2006, 2702-2704 and SHKim, L.-C-Chien, Jpn. J. Appl. Phys. 43,2004, 7643-7647. PS-IPS displays are described, for example, in US 6,177,972 and Appl. Phys. Lett. 1999, 75(21), 3264. PS-TN displays are described, for example, in Optics Express 2004, 12(7), 1221.

In particular, for monitors and especially TV applications, there is a continuing need to optimize the response time and contrast and brightness (and therefore transmittance) of LC displays. The PSA approach here provides key advantages.

A straightforward way to reduce the response time is to reduce the LC cell gap while using a higher birefringence LC mixture in order to maintain the necessary phase delay. In this connection, the liquid crystal dropping (ODF) method allows a thinner cell gap (d < 4 μm) to be made while maintaining high manufacturing yield. The LC material is directly dropped onto the first substrate according to the ODF method disclosed in, for example, US 2003-0147040 A1, and then the LC unit and the second substrate are assembled.

However, it is widely known by experts that drop mura defects may occur when manufacturing PSA display panels. For example, US 8,501,286 B2 discloses that when the cell gap of the PSA-VA display is changed to less than 3.8 μm, it causes the reactive monomer in the LC mixture to be incapable of being widely dispersed in a large region of the surface of the polyimide film of the alignment film, And thus the reactive monomers of different amounts of the LC mixture are unevenly deposited on the surface of the polyimine (PI) of the alignment film. To solve this problem, the author suggests using the following formula:

However, it goes without saying that the limited use of such compounds is a severe limitation in the development of further mixtures.

Another proposed solution to the above problem is disclosed in KR 2011-0068303. Among them, the authors suggest a liquid crystal mixture comprising an additive for reducing the surface tension of the LC mixture. Suggested additives include oxoxane-based compounds such as polydimethyl methoxyalkane (poly-dimethyl decane or PDMS). However, details regarding the additives employed and suitable liquid crystal mixture compositions are not disclosed at all.

Accordingly, there is still a great need for PSA displays, particularly VA-type PSA displays, and alternative LC media for such displays that do not have the disadvantages described above or have only a minor degree of the disadvantages described above and have Improved features. In particular, PSA displays and materials for PSA displays are highly desirable, which promote high specific resistance while promoting large operating temperature ranges, short response times (even at low temperatures) and low threshold voltages, low pre-tilt, gray A wide range of degrees, high contrast and wide viewing angle, and a high value of voltage retention (VHR) after UV exposure.

Accordingly, the present invention has the object of providing a novel suitable material for a PSA display, in particular a VA-type PSA display, which does not have the disadvantages indicated above or only has a minor degree of the disadvantages indicated above, as fast as possible. And fully polymerized, achieving a lower pre-tilt to be established, reducing or preventing dropouts in the display, and at the same time preferably promoting very high specific resistance values, lower threshold voltages, and shorter response times.

Surprisingly, the inventors have discovered that the above defined requirements can be achieved by an LC medium comprising one or more non-polymerizable liquid crystal primordial compounds, one or more polymerizable liquid crystal primordial compounds and one or more compounds of formula I and The disadvantages of the prior art LC media mentioned can be overcome,

Wherein R ^a represents hydrogen or a hydrocarbon having 1 to 20 carbon atoms; preferably, a linear or branched alkyl group having 1 to 20 carbon atoms, wherein one or more non-terminal CH ₂ groups may Substitution of -O-, -NH-, -CH=CH-, -CONH-, -CO-, -OCO- or -COO- in such a manner that the O atoms are not directly connected to each other, having a stretching of 3 to 8 carbon atoms a cycloalkyl group or a aryl group having 6 to 10 carbon atoms, wherein the hydrogen atom may be substituted by halogen, or a hydrocarbon group having 1 to 4 carbon atoms, such as phenyl, benzyl, methylphenyl or methoxy a phenyl group, R ^c represents a hydrocarbon having 1 to 20 carbon atoms; preferably a linear or branched alkyl group having 1 to 20 carbon atoms, wherein one or more non-terminal CH ₂ groups may be made The O atoms are not directly connected to each other by -O-, -NH-, -CH=CH-, -CONH-, -CO-, -OCO- or -COO-, and have a ring of 3 to 8 carbon atoms. An alkyl group or a aryl group having 6 to 10 carbon atoms, wherein the hydrogen atom may be substituted by halogen, or a hydrocarbon group having 1 to 4 carbon atoms, such as phenyl, benzyl, methylphenyl or methoxy phenyl, R ^b, and R ^d represents hydrogen or alkyl having from 1 to 8 Hydrocarbon atoms, preferably a hydrogen, a linear or branched chain of 1 to 4 carbon atoms in the alkylene group, wherein the -CH ₂ - can manner that O atoms are not directly connected to each other via the -O -, - NH-, -CH=CH-, -CONH-, -CO-, -OCO- or -COO-substitution, Z ^a represents -O- or a single bond, and n is an integer from 0 to 10, preferably 0, 1, 2 , 3

Furthermore, the present invention relates to the use of an LC medium according to the present invention in PS and PSA displays, in particular in situ polymerization of a polymerizable liquid crystal in a PSA display by applying an electric or magnetic field in a PSA-VA display containing an LC medium. Base compound for use in LC media The purpose of creating a tilt angle.

Furthermore, the invention relates to an LC display comprising an LC medium according to the invention, in particular a PS or PSA display, preferably a PSA-VA display.

Furthermore, the present invention relates to a PS or PSA type LC display containing an LC unit, particularly a PSA-VA display, which is composed of two substrates, at least one of which is light transmissive and at least one of which has an electrode layer. And an LC dielectric layer comprising a polymeric component and a low molecular weight component disposed between the substrates, wherein the polymeric component is polymerizable by polymerizing one or more polymerizable liquid crystals between the substrates of the LC cells in the LC medium under application of a voltage Base compound to obtain.

Furthermore, the present invention relates to a process for preparing an LC medium as described above and below by mixing one or more non-polymerisable liquid crystal primordial compounds, one or more polymerizable liquid crystal primord compounds and one or more compounds of formula I.

Furthermore, the present invention relates to a method of producing an LC display, preferably a PSA-VA display, as described above and below, by mixing one or more non-polymerizable liquid crystal primordial compounds, one or more polymerizable liquid crystal primordial compounds And one or more organic hydrazine compounds of the formula I or its individual forms, and optionally other liquid crystal compounds and/or additives, the LC material is directly dropped onto the substrate before assembling the two substrates, and the two substrates are assembled, and The polymerizable liquid crystal primordial compound is polymerized under application of a voltage.

Definitions and terms

Unless otherwise indicated, the term "PSA" is used to mean a PS display and a PSA display.

As used herein, the terms "tilt" and "tilt angle" mean the oblique alignment of the LC molecules of the LC medium relative to the surface of the cells in the LC display (here preferably the PSA display). The tilt angle here represents the average angle (<90°) between the longitudinal molecular axis of the LC molecule (LC director) and the surface of the plane-parallel outer plate forming the LC cell. Here, the low tilt angle value (i.e., the deviation from the 90° angle) corresponds to a large tilt. The fit of the measurement tilt angle is given in the example. method. The tilt angle values disclosed above and below are related to this measurement method unless otherwise indicated.

The term "liquid crystal primordium" or "liquid crystal primordium group" as used herein is known to those skilled in the art and is described in the literature, and is meant to be fundamentally due to the anisotropy of its attraction and repulsive interactions. It contributes to the formation of a liquid crystal (LC) phase group in a low molecular weight or polymeric substance. The compound containing a liquid crystal primordium group (liquid crystal primordial compound) does not necessarily have to have an LC phase by itself. It is also possible for the liquid crystal priming compound to exhibit LC phase behavior only after mixing with other compounds and/or after polymerization. Typical liquid crystal primordial groups are, for example, rigid rod or disk shaped units.

An overview of the terms and definitions used in connection with liquid crystal primordia or LC compounds is found in Pure Appl. Chem. 73 (5), 888 (2001) and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116. , given in 6340-6368.

As used herein, the terms "polymerizable liquid crystal primordial compound", "reactive liquid crystal primordium" and "RM" mean a compound containing a liquid crystal priming group and one or more functional groups suitable for polymerization, The latter is also known as "polymerizable group" or "P".

Unless otherwise stated, the term "polymerizable compound" as used hereinafter means a polymerizable monomer compound.

As used herein, the terms "low molecular weight compound" and "non-polymerizable liquid crystal primordial compound" mean a liquid crystal primordial compound, usually a monomeric liquid crystal primordial compound, under common conditions known to those skilled in the art, especially The functional group suitable for polymerization is not contained under the conditions for polymerizing RM.

As used herein, the terms "active layer" and "switchable layer" mean a layer in an electro-optic display (eg, an LC display) that contains one or more molecules having structural and optical anisotropy, such as, for example, LC. A molecule that changes its orientation after an external stimulus, such as an electric or magnetic field, resulting in a change in the transmittance of the layer to polarized or unpolarized light.

The "organic group" above and below means a carbon group or a hydrocarbon group.

"Carbo-based" means a monovalent or polyvalent organic radical containing at least one carbon atom, wherein this is free of other atoms (eg, -C≡C-) or, as appropriate, one or more other atoms, such as N, O, S. , P, Si, Se, As, Te or Ge (for example, carbonyl, etc.).

The term "hydrocarbyl" denotes a carbon radical additionally containing one or more H atoms and optionally one or more heteroatoms (eg, N, O, S, P, Si, Se, As, Te or Ge).

The carbyl or hydrocarbyl group can be a saturated or unsaturated group. The unsaturated group is, for example, an aryl group, an alkenyl group or an alkynyl group. The carbon group or hydrocarbon group having more than 3 C atoms may be linear, branched, and/or cyclic, and may also contain a spiro bond or a condensed ring.

The terms "alkyl", "aryl", "heteroaryl" and the like also encompass polyvalent groups such as alkyl, aryl, heteroaryl and the like.

The term "aryl" means an aromatic carbon group or a group derived therefrom.

In this connection, structural formula Have and The same representation.

The term "heteroaryl" means an "aryl" group containing one or more heteroatoms as defined above.

Preferred carbon and hydrocarbyl groups are optionally substituted alkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl groups having from 1 to 40, preferably from 1 to 25, and most preferably from 1 to 18, C atoms. , alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy, optionally substituted aryl or aryloxy having 6 to 40, preferably 6 to 25, C atoms, or optionally Substituted alkaryl, aralkyl, alkylaryloxy, arylalkoxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy having 6 to 40, preferably 6 to 25, C atoms And aryloxycarbonyloxy.

More preferred carbon and hydrocarbyl groups are C ₁ -C ₄₀ alkyl, C ₂ -C ₄₀ alkenyl, C ₂ -C ₄₀ alkynyl, C ₃ -C ₄₀ allyl, C ₄ -C ₄₀ alkyldienyl , C ₄ -C ₄₀ polyalkenyl, C ₆ -C ₄₀ aryl, C ₆ -C ₄₀ alkaryl, C ₆ -C ₄₀ aralkyl, C ₆ -C ₄₀ alkylaryloxy, C ₆ - C ₄₀ arylalkoxy, C ₂ -C ₄₀ heteroaryl, C ₄ -C ₄₀ cycloalkyl, C ₄ -C ₄₀ cycloalkenyl, and the like. More preferably, it is a C ₁ -C ₂₂ alkyl group, a C ₂ -C ₂₂ alkenyl group, a C ₂ -C ₂₂ alkynyl group, a C ₃ -C ₂₂ allyl group, a C ₄ -C ₂₂ alkyldienyl group, a C ₆ - C ₁₂ aryl, C ₆ -C ₂₀ aralkyl and C ₂ -C ₂₀ heteroaryl.

More preferably, the carbon group and the hydrocarbon group are a linear, branched or cyclic alkyl group having 1 to 40, preferably 1 to 25, C atoms which are unsubstituted or monosubstituted by F, Cl, Br, I or CN. Or multiple substitutions, and wherein one or more of the non-adjacent CH ₂ groups may be such that the O atoms and/or the S atoms are not directly connected to each other by -C(R ^x )=C(R ^x )- , -C≡C-, -N(R ^x )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-.

R ^x preferably represents H, a halogen, a linear, branched or cyclic alkyl group having 1 to 25 C atoms, and wherein one or more of the non-adjacent C atoms may pass through -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- substitution, and one or more of the H atoms may have 6 to 40 C atoms via fluorine, optionally substituted Aryl or aryloxy or, as the case may be, substituted heteroaryl or heteroaryloxy having 2 to 40 C atoms.

Preferred alkoxy groups are, for example, methoxy, ethoxy, 2-methoxyethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, second butoxy, Third butoxy, 2-methylbutoxy, n-pentyloxy, n-hexyloxy, n-heptyloxy, n-octyloxy, n-decyloxy, n-decyloxy, n-undecyloxy, N-dodecyloxy and the like.

Preferred alkyl groups are, for example, methyl (Me), ethyl (Et), n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, t-butyl, 2-methylbutyl , n-pentyl, second amyl, cyclopentyl, n-hexyl, cyclohexyl, 2-ethylhexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, n-decyl, n-decyl, N-undecyl, n-dodecyl, dodecyl, trifluoromethyl, perfluoro-n-butyl, 2,2,2-trifluoroethyl, perfluorooctyl, perfluorohexyl, and the like.

Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctene Base.

Preferred alkynyl groups are, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, octynyl and the like.

Preferred alkoxy groups are, for example, methoxy (OMe), ethoxy (OEt), 2-methoxyethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, Second butoxy, tert-butoxy, 2-methylbutoxy, n-pentyloxy, n-hexyloxy, n-heptyloxy, n-octyloxy, n-decyloxy, n-decyloxy, positive Undecyloxy, n-dodecyloxy, and the like.

Preferred amine groups are, for example, dimethylamino, methylamino, methylphenylamino, phenylamino and the like.

The aryl and heteroaryl groups may be monocyclic or polycyclic, that is, they may contain one ring (eg, phenyl) or two or more rings, which may also be fused (eg, naphthalene) Or covalently bonded (eg, biphenyl), or a combination of a fused ring and a bonded ring. The heteroaryl group contains one or more heteroatoms preferably selected from the group consisting of O, N, S and Se.

More preferably, it is a monocyclic, bicyclic or tricyclic aryl group having 6 to 25 C atoms and a monocyclic, bicyclic or tricyclic heteroaryl group having 5 to 25 ring atoms, which optionally contains a fused ring and optionally Replace. Further, it is preferably 5 members, 6 members or 7 members of an aryl group and a heteroaryl group, and further, one or more of the CH groups may be such that the O atoms and/or the S atoms are not directly connected to each other via N, S, Or O replacement.

Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl, [1,1':3',1"]biphenyl-2'-yl, naphthyl, anthracene, binaphthyl, phenanthrene, 9, 10-dihydro-phenanthrene, anthracene, dihydroanthracene, And benzophenone, pentacene, benzopyrene, anthracene, anthracene, anthracene, and snail.

Preferred heteroaryl groups are, for example, 5-membered rings such as pyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, furan, thiophene, selenophene, oxazole, Isoxazole, 1,2-thiazole, 1,3-thiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3, 4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole; 6-membered ring, Such as pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, 1,2,4,5-tetrazine, 1 , 2,3,4-tetrazine, 1,2,3,5-tetrazine; or a condensing group such as anthracene, isoindole, pyridazine, oxazole, benzimidazole, benzotriazole, Anthraquinone, naphthyl imidazole, phenimidazole, pyridazole, pyrazinazole, quinoxaline imidazole, benzoxazole, naphthoxazole, anthraquinone, phenanthroxazole, isoxazole, benzothiazole, benzo Furan, isobenzofuran, dibenzofuran, quinoline, isoquinoline, acridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinaline Porphyrin, benzoisoquinoline, acridine, phenothiazine, phenoxazine, benzoxazine, benzopyrimidine, quinoxaline, phenazine, Pyridine, azacarbazole, benzoporphyrin, phenanthridine, phenanthroline, thieno[2,3b]thiophene, thieno[3,2b]thiophene, dithienothiophene, isobenzothiophene, dibenzothiophene , benzothiadiazole thiophene or a combination of such groups.

The aryl and heteroaryl groups mentioned above and below may also be alkyl, alkoxy, thioalkyl, fluoro, fluoroalkyl or other aryl or heteroaryl groups, such as benzyl, methylbenzene Substituted with a methoxyphenyl group or the like.

The (non-aromatic) alicyclic and heterocyclic groups encompass both saturated rings (i.e., rings containing only a single bond) and partially unsaturated rings (i.e., may also contain a ring of complex bonds). The heterocycle contains one or more heteroatoms preferably selected from the group consisting of Si, O, N, S and Se.

The (non-aromatic) alicyclic and heterocyclic groups may be monocyclic, that is, contain only one ring (for example, cyclohexane); or may be polycyclic, that is, contain a plurality of rings (for example, decahydrogen) Naphthalene or bicyclooctane). It is especially preferred to be a saturated group. Further, a monocyclic, bicyclic or tricyclic group having 5 to 25 ring atoms is preferred, which optionally contains a fused ring and is optionally substituted. Further preferred is a 5-membered, 6-membered, 7-membered or 8-membered carbocyclic group, in which one or more C atoms may be replaced by Si and/or one or more CH groups may be replaced by N and/or Or a plurality of non-adjacent CH ₂ groups may be replaced by -O- and/or -S-.

Preferred alicyclic and heterocyclic groups are, for example, a 5-member group such as cyclopentane, tetrahydrofuran, tetrahydrofuran, pyrrolidine; a 6-member group such as cyclohexane, cyclohexane, cyclohexene , tetrahydropyran, tetrahydrothiopyran, 1,3-dioxane, 1,3-dithiane, piperidine; a 7-member group such as cycloheptane; and a condensed group such as four Hydronaphthalene, decahydronaphthalene, indane, bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2 , 6-diyl, octahydro-4,7-methyl bridge indole-2,5-diyl.

Preferred substituents are, for example, groups which promote solubility, such as alkyl or alkoxy groups; An electron group such as fluorine, nitro or nitrile; or a substituent for increasing the glass transition temperature (Tg) in the polymer, especially a bulky group such as a tert-butyl group or an optionally substituted aryl group.

Preferred substituents, also referred to above as "L", are, for example, F, Cl, Br, I, -CN, -NO ₂ , -NCO, -NCS, -OCN, -SCN, -C(=O N(R ^x ) ₂ , -C(=O)Y ¹ , -C(=O)R ^x , -N(R ^x ) ₂ , wherein R ^x has the meaning indicated above, and Y ¹ represents halogen An aryl group having 6 to 40, preferably 6 to 20, C atoms, as appropriate; and a linear or branched alkyl group having 1 to 25 C atoms, an alkoxy group, an alkylcarbonyl group, an alkane An oxycarbonyl group, an alkylcarbonyloxy group or an alkoxycarbonyloxy group in which one or more H atoms are optionally substituted by F or Cl.

"Substituted aryl" preferably means halogen, -CN, R ⁰ , -OR ⁰ , -CO-R ⁰ , -CO-OR ⁰ , -O-CO-R ⁰ or -O-CO-OR Substitution ⁰ , wherein R ⁰ has the meaning indicated above.

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

Preferred or Where L has one of the meanings indicated above.

The term "halogen" means F, Cl, Br or I.

-CO-, -C(=O)-, and -C(O)- represent a carbonyl group, that is,

The term "conjugated group (conjugated radical / conjugated group)" means primarily comprising sp ² - hybridization (or may also sp- hybridized) carbon atoms of the group, which may also substituted by the corresponding hetero atom. In the simplest case, this means that there are alternating double and single bonds. In this connection, "main" means that the natural (non-random) existence of a conjugate break does not depreciate the term "conjugation". Furthermore, the term "conjugate" is equally used in this application if, for example, an arylamine unit or a certain heterocycle (i.e., conjugated via an N, O, P or S atom) is positioned in a group.

The term "polymerizable group" (P ^1-3 ) means suitable for polymerization (for example, radical or ionic chain polymerization, addition polymerization or polycondensation) or polymer-like reaction (for example, addition or condensation to the main polymerization). a group on the chain). Particularly preferred are groups for chain polymerization, especially those having a C=C double bond or a -C≡C-parallel bond, and a group suitable for ring opening polymerization, such as oxetane or Epoxy group.

Preferred groups P ^{1-3 are} selected from the group consisting of CH ₂ =CW ¹ -CO-O-, CH ₂ =CW ¹ -CO-, , CH ₂ =CW ² -(O) _k3 -, CW ¹ =CH-CO-(O) _k3 -, CW ¹ =CH-CO-NH-, CH ₂ =CW ¹ -CO-NH-,CH ₃ - CH=CH-O-, (CH ₂ =CH) ₂ CH-OCO-, (CH ₂ =CH-CH ₂ ) ₂ CH-OCO-, (CH ₂ =CH) ₂ CH-O-, (CH ₂ = CH-CH ₂ ) ₂ N-, (CH ₂ =CH-CH ₂ ) ₂ N-CO-, HO-CW ² W ³ -, HS-CW ² W ³ -, HW ² N-, HO-CW ² W ³ -NH-, CH ₂ =CW ¹ -CO-NH-,CH ₂ =CH-(COO) _k1 -Phe-(O) _k2 -,CH ₂ =CH-(CO) _k1 -Phe-(O) _k2 -, Phe-CH=CH-, HOOC-, OCN- and W ⁴ W ⁵ W ⁶ Si-, wherein W ¹ represents H, F, Cl, CN, CF ₃ , phenyl or has 1 to 5 C atoms Alkyl groups, especially H, F, Cl or CH ₃ , W ² and W ³ each independently represent H or an alkyl group having 1 to 5 C atoms, especially H, methyl, ethyl or n-propyl, W ⁴ , W ⁵ and W ⁶ each independently represent Cl, an oxaalkyl group having 1 to 5 C atoms or an oxacarbonylalkyl group, and W ⁷ and W ⁸ each independently represent H, Cl or have 1 to An alkyl group of 5 C atoms, Phe represents a 1,4-phenylene group, optionally substituted by one or more groups other than P-Sp- as defined above, k ₁ , k ₂ and k ₃ each independently represents 0 or 1, k _{3 is} better 1 and k ₄ represent an integer of 1 to 10.

The Group ^{1-3 is} selected from the group consisting of CH ₂ =CW ¹ -CO-O-, CH ₂ =CW ¹ -CO-, , CH ₂ =CW ² -O-, CH ₂ =CW ² -, CW ¹ =CH-CO-(O) _k3 -, CW ¹ =CH-CO-NH-, CH ₂ =CW ¹ -CO-NH- , (CH ₂ =CH) ₂ CH-OCO-, (CH ₂ =CH-CH ₂ ) ₂ CH-OCO-, (CH ₂ =CH) ₂ CH-O-, (CH ₂ =CH-CH ₂ ) ₂ N-, (CH ₂ =CH-CH ₂ ) ₂ N-CO-, CH ₂ =CW ¹ -CO-NH-, CH ₂ =CH-(COO) _k1 -Phe-(O) _k2 -, CH ₂ = CH-(CO) _k1 -Phe-(O) _k2 -, Phe-CH=CH- and W ⁴ W ⁵ W ⁶ Si-, wherein W ¹ represents H, F, Cl, CN, CF ₃ , phenyl or have An alkyl group of 1 to 5 C atoms, especially H, F, Cl or CH ₃ , W ² and W ³ each independently represent H or an alkyl group having 1 to 5 C atoms, especially H, methyl, B Or n-propyl, W ⁴ , W ⁵ and W ⁶ each independently represent Cl, an oxaalkyl group having 1 to 5 C atoms or an oxacarbonylalkyl group, and W ⁷ and W ⁸ are each independently represented H, Cl or an alkyl group having 1 to 5 C atoms, Phe represents a 1,4-phenylene group, and k ₁ , k ₂ and k ₃ each independently represent 0 or 1, and k ₃ preferably represents 1 and k ₄ represents an integer from 1 to 10.

The extremely preferred group P ^{1-3 is} selected from the group consisting of CH ₂ =CW ¹ -CO-O-, especially CH ₂ =CH-CO-O-, CH ₂ =C(CH ₃ )-CO -O- and CH ₂ =CF-CO-O-, in addition CH ₂ =CH-O-, (CH ₂ =CH) ₂ CH-O-CO-, (CH ₂ =CH) ₂ CH-O-,

Other extremely preferred groups P ^{1-3 are} selected from the group consisting of vinyl, vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxocycle Butane and epoxy, and particularly preferably acrylate, methacrylate or oxetane.

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

In particular, if the spacer group Sp ^{1-3 is} different from the single bond, it is preferably of the formula Sp"-X" such that the respective groups P ⁱ -Sp ⁱ - (e.g., P ¹ -Sp ¹ -) are in conformity The formula P-Sp"-X"-, where Sp" and X" have the meanings given below.

If the spacer group Sp ^{4 is} different from the single bond, it is preferably of the formula X"-Sp" such that the respective groups -A ² -Sp ⁴ - conform to the formula -A ² -X"-Sp"-, where Sp "And X" has the meaning given below.

Sp" represents an alkylene group having 1 to 20, preferably 1 to 12, C atoms, which may be mono- or polysubstituted by F, Cl, Br, I or CN as appropriate, and additionally, one or more of them are not The adjacent CH ₂ groups may be such that the O atoms and/or the S atoms are not directly connected to each other by -O-, -S-, -NH-, -N(R ⁰ )-, -Si(R) independently of each other. ⁰⁰ R ⁰⁰⁰ )-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -S-CO-, -CO-S-, -N(R ⁰⁰ )-CO -O-, -O-CO-N(R ⁰⁰ )-, -N(R ⁰⁰ )-CO-N(R ⁰⁰ )-, -CH=CH- or -C≡C-substitution, X" for -O -, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CO-N(R ⁰⁰ )-, -N(R ⁰⁰ )-CO-, -N(R ⁰⁰ )-CO-N(R ⁰⁰ )-, -OCH ₂ -, -CH ₂ O-, -SCH ₂ -, -CH ₂ S-, -CF ₂ O-, -OCF ₂ -, - CF ₂ S-, -SCF ₂ -, -CF ₂ CH ₂ -, -CH ₂ CF ₂ -, -CF ₂ CF ₂ -, -CH=N-, -N=CH-, -N=N-, - CH=CR ⁰ -, -CY ² =CY ³ -, -C≡C-, -CH=CH-CO-O-, -O-CO-CH=CH- or a single bond, R ⁰⁰ and R ⁰⁰⁰ are each other H or an alkyl group having 1 to 12 C atoms is independently represented, and Y ² and Y ³ each independently represent H, F, Cl or CN.

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

A typical spacer group -Sp"-X"- is, for example, -(CH ₂ ) _p1 -, -(CH ₂ CH ₂ O) _q1 -CH ₂ CH ₂ -, -CH ₂ CH ₂ -S-CH ₂ CH ₂ -, -CH ₂ CH ₂ -NH-CH ₂ CH ₂ - or -(SiR ⁰⁰ R ⁰⁰⁰ -O) _p1 -, wherein p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R ⁰⁰ and R ⁰⁰⁰ has the meaning indicated above.

尤佳基-Sp"-X"- is -(CH ₂ ) _p1 -, -(CH ₂ ) _p1 -O-, -(CH ₂ ) _p1 -O-CO-, -(CH ₂ ) _p1 -O -CO-O-, wherein p1 and q1 have the meanings indicated above.

The Eugene group -X"-Sp"- is -(CH ₂ ) _p1 -, -O-(CH ₂ ) _p1 -, -CO-O-(CH ₂ ) _p1 -, -O-CO-O-( CH ₂ ) _p1 -, wherein p1 and q1 have the meanings indicated above.

In each case, the preferred group "Sp" is, for example, a straight-chain ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, a decyl group, a hydrazine group, a hydrazine group, Exedecyl, dodecyl, octadecyl, ethyl ethixoethyl, methyleneoxy butyl, ethyl thioethyl, ethylene-N-methylimine Base ethyl, 1-methylalkyl, vinyl, propylene and butenyl.

According to a preferred embodiment of the invention, the compound of formula I is dissolved or suspended in the other components of the LC medium.

According to the present invention, the LC medium is a liquid crystal composition suitable for liquid crystal dropping (ODF) technology.

To control the alignment of the LC medium, the surface of the support substrate, such as glass, is typically coated with a polymer. The polymer may be any one having at least one polar group selected from a carboxyl group, a hydroxyl group and an amine group in a molecular chain of the polymer. Preferably, the polymer is a polyimine type polymer. The solution of the polyimine polymer can be referred to as a polyimide varnish.

When the polyimide varnish is applied to the support substrate to treat the support surface, the solvent is then preferably removed at a temperature between 50 ° C and 250 ° C, and thereby a polymer film is formed. The polyimide film type polymer film thus formed on the support substrate can be subjected to physical or mechanical surface treatment such as rubbing. For the rubbing treatment, any method can be employed. Examples of rubbing treatments are described and are known to those skilled in the art. Winding a rubbing cloth of crepe, cotton, polyamide or the like onto a metal roll, and rotating and moving the roll while being in contact with the support substrate or the polymer film; or moving only the support substrate without moving the rotation The position of the roller.

A polyimide varnish capable of forming a polymer film on a support substrate is a polymer component (such as polylysine, polyamidoamine, polyamidomate, soluble polyimine or polyamidoxime) Amine) A varnish composition dissolved in a solvent. The varnish composition is applied to a support support and subsequently dried to form a polymer film thereon. The polymer component constituting the polymer film may be a copolymer such as a random copolymer or a block copolymer, and may be a mixture of different types of polymer components.

The polyimine type polymer which is preferably used for forming a polymer film is an esterified group having a guanamine bond, a ruthenium bond, a carboxyl group derived from ruthenium iodide, a guanidino group of a carboxyl group or a carboxyl group. The polymer of the group. Preferred examples of polymers of this type are polylysine, polyamidoguanamine and polyphthalamide. However, in the present invention, in addition to these preferred polymers, soluble polyimine obtained by dehydration of polyglycolic acid and polyamidamine-imine is also suitable. Among them, poly-proline and polyamidoamine are more preferred; and poly-proline is preferred.

The tetracarboxylic dianhydride used to obtain the above-mentioned poly-proline, polyamidamine, polyphthalate, soluble polyimine or polyamidimide may belong to an aromatic compound Any of a group of (including a heterocyclic aromatic compound) in which a dicarboxylic anhydride is directly bonded to an aromatic ring; or a group of an aliphatic compound (including a heterocyclic aliphatic compound), wherein a dicarboxylic acid The anhydride is not directly bonded to the aromatic ring.

In a preferred embodiment of the invention, the transparent substrate is a polymer substrate, preferably a polyimide substrate (RI) substrate, for example, produced by using JSR-2347 (JSR) and JSR-2503 (JSR). Polyimine (PI) substrate.

Typically, the surface energy of a polyimide film produced by using SE-4811 (Nissan Chemical), which is a commercial polyimide resin and used to produce a VA layer in the LCD industry, is about 31 mJ/m ² .

The surface energy of the alignment layer can be determined by methods known to those skilled in the art, such as by contact angle measurements using a Kruss DSA-100 instrument.

Although the correlation between surface energy and molecular alignment has not been clearly elucidated, it has been accepted that a surface having a low surface energy will also support the VA of the LC molecule.

According to the present invention, the compound of the formula I reduces the surface tension (or interfacial tension) between the liquid crystal composition and the alignment layer, and reduces the ductility of the liquid crystal composition provided on the alignment layer by the liquid crystal dropping method, thereby improving the reactivity single The body is uniformly distributed in the LC dielectric layer adjacent to the surface of the alignment layer, and thus the occurrence of drop dead spots is avoided or reduced.

And theory (see Lee et al. In Photonics Letters of Poland 2010, 3, (1), pages 8-10 and Schwartz et al. In ACS Appl. Mater. Interfaces 2011, 3, (11), pp. 4374-4380 a good agreement, but not limited to or bound by theory, the inventors of the present invention can chemically or physically interact with the surface of the alignment layer while forming a self-aligning layer on the surface of the alignment layer, wherein the surface energy of the alignment layer reduce.

For the production of PSA displays, the polymerizable compound is polymerized or crosslinked (if one compound contains two or more polymerizable groups) by in situ polymerization in an LC medium between substrates of the LC display under application of a voltage. Aggregation can be done in one step. It is also possible to first carry out the polymerization in the first step under application of a voltage in order to generate a pretilt angle, and then to polymerize or crosslink the unreacted compound in the first step without applying a voltage in the second polymerization step ("final Cured").

Suitable and preferred polymerization methods are, for example, thermal or photopolymerization, preferably photopolymerization, especially UV photopolymerization. One or more initiators may also be added here as appropriate. Suitable conditions for polymerization and suitable types and amounts of initiators are known to those skilled in the art and are described in the literature. Suitable for free radical polymerization are, for example, commercially available photoinitiators Irgacure 651®, Irgacure 184®, Irgacure 907®, Irgacure 369® or Darocure 1173® (Ciba AG). If an initiator is used, the proportion thereof is preferably from 0.001% by weight to 5% by weight, particularly preferably from 0.001% by weight to 1% by weight.

The polymerizable compounds according to the invention are also suitable for the polymerization without the need for initiators, which are accompanied by a number of advantages, such as lower material costs and, in particular, less contamination of the LC medium due to possible residual amounts of initiators or their degradation products. Therefore, the polymerization can also be carried out without adding an initiator. In a preferred embodiment, the LC medium thus does not comprise a polymerization initiator.

The LC medium may also contain one or more stabilizers to prevent undesired spontaneous polymerization of the RM, for example during storage or transportation. Suitable types and amounts of stabilizers are known to those skilled in the art and are described in the literature. Particularly suitable are, for example, commercially available stabilizers from the Irganox® range (Ciba AG), such as Irganox® 1076. If a stabilizer is used, the proportion thereof is preferably from 10 ppm to 500,000 ppm, particularly preferably from 50 ppm to 50,000 ppm, based on the total amount of RM or polymerizable component A).

More preferably, it is an LC medium containing one, two or three polymerizable liquid crystal primordial compounds.

More preferably, it is an LC medium comprising one, two or three compounds of the formula I.

More preferably, it is an LC medium containing one, two, three or more non-polymerizable liquid crystal primordial compounds.

The proportion of the polymerizable compound in the LC medium according to the present invention is preferably from >0 to <5%, particularly preferably from 0 to <1%, and particularly preferably from 0.01% to 0.5%.

The proportion of the non-polymerizable liquid crystal primordial compound in the LC medium according to the present invention is preferably from 95% to <100%, particularly preferably from 99% to <100%.

The LC medium according to the invention for PSA displays preferably comprises from 0 to <20% by weight, particularly preferably from 0 to <5% by weight, very preferably from 0.01% to 0.5% by weight of the compound of the formula I.

Further, an LC medium having a nematic liquid crystal phase is preferred.

Furthermore, an LC medium according to the invention is preferred, wherein the compound is completely selected from the group consisting of non-palphalinic compounds.

Preferably, as described above and below, the LC medium according to the present invention consists essentially of one or more polymerizable liquid crystal priming compounds, one or more non-polymerizable liquid crystal primord compounds, and one or more compounds of formula I.

However, the LC medium may additionally comprise one or more other components or additives, preferably selected from, but not limited to, the following list: comonomers, palmitic dopants, polymerization initiators, inhibitors, stabilizers, Surfactants, wetting agents, lubricants, dispersants, hydrophobic agents, adhesives, flow improvers, defoamers, degassing agents, diluents, reactive diluents, auxiliaries, colorants, dyes, pigments and Nano particles.

Suitable and preferred compounds of the formula I are for example selected from the formula:

Wherein R ^a , R ^b , R ^c , R ^d and n have one of the meanings given according to formula I.

Further, a preferred compound of the formula I, for example selected from the group consisting of:

Wherein R ^a , R ^c and n have one of the meanings given according to formula I.

Preferred compounds of the formulae A1 to C4 are selected from the group consisting of wherein R ^a represents hydrogen, methyl, ethyl, methoxy, ethoxy, phenyl, benzyl, methylphenyl or methoxyphenyl and R ^c and n has a compound as one of the meanings given according to formula I.

More preferred compounds of formula A1 to C4 are selected from the group consisting of wherein R ^a represents hydrogen, methyl, ethyl, methoxy, ethoxy, phenyl, benzyl, methylphenyl or methoxyphenyl; R ^{c is} independently Wherein R ^a represents methyl, ethyl, methoxy, ethoxy, phenyl, benzyl, methylphenyl or methoxyphenyl; and n has one of the meanings given according to formula I Compound.

Examples of particularly good compounds are given below:

Wherein n represents 1, 2, 3 or 4.

Preferably, it comprises one or more polymerizable compounds containing a polymerizable group (single reactivity), and/or one or more of two or more, preferably two, polymerizable groups (dual reactive or Multi-reactive) LC media of polymerizable compounds.

The polymerizable compound can be polymerized separately, but it is also possible that the polymerization contains two or two A mixture of the above polymerizable compounds or a mixture comprising one or more polymerizable compounds and one or more other polymerizable compounds ("comonomers"), which are preferably liquid crystal primaries or liquid crystals. In the case of polymerizing the mixtures, a copolymer is formed.

Suitable and preferred polymerizable liquid crystal primordial compounds (especially for PSA-VA displays) are for example selected from the formula:

Wherein the individual groups have the following meanings: P ¹ , P ² and P ³ each independently represent a polymerizable group, preferably having one of the meanings indicated above and below for P, particularly preferably an acrylate group. a methacrylate group, a fluoroacrylate group, an oxetanyl group, a vinyl group, a vinyloxy group or an epoxy group, and Sp ¹ , Sp ² and Sp ³ each independently represent a single bond or a spacer group Preferably, it has one of the meanings indicated above and below for Sp, and particularly preferably -(CH ₂ ) _p1 -, -(CH ₂ ) _p1 -O-, -(CH ₂ ) _p1 -CO- O- or -(CH ₂ ) _p1 -O-CO-O-, wherein p1 is an integer from 1 to 12, and wherein in the last-mentioned group, attachment to an adjacent ring is carried out via an O atom, in addition, wherein the group One or more of P ¹ -Sp ¹ -, P ¹ -Sp ² - and P ³ -Sp ³ - may represent R ^aa , with the restriction that the groups P ¹ -Sp ¹ -, P ² - are present. At least one of Sp ² and P ³ -Sp ³ - does not represent R ^aa , and R ^aa represents H, F, Cl, CN or a linear or branched alkyl group having 1 to 25 C atoms, and one of them or more non-adjacent CH ₂ groups may be such that an O atom and / or the original S The embodiment is not connected directly to one another independently of one another are each substituted with ^{C (R 0) = C (} R 00) -, - C≡C-, C (R 0) = C (R 00) -, - C≡C -, - N(R ⁰ )-, -O-, -S-, -CO-, -CO-O-, O-, -O-CO-, -O-CO-O-, and in addition, one or more of them H atoms may be through F; Cl; CN; or P ¹ -Sp ¹ -; particularly preferably having a linear or branched chain of 1 to 12 C atoms, monofluorinated or polyfluorinated alkyl, alkoxy An alkenyl group, an alkynyl group, an alkylcarbonyl group, an alkoxycarbonyl group, an alkylcarbonyloxy group or an alkoxycarbonyloxy group (wherein the alkenyl group and the alkynyl group have at least two C atoms and the branched chain group has at least three Substituting C atoms), each of R ⁰ and R ⁰⁰ represents H or an alkyl group having 1 to 12 C atoms independently of each other and identically or differently, and R ^y and R ^z each independently represent H , F, CH ₃ or CF ₃ , X ¹ , X ² and X ³ each independently represent -CO-O-, -O-CO- or a single bond, and Z ¹ represents -O-, -CO-, -C (R ^y R ^z )- or -CF ₂ CF ₂ -, Z ² and Z ³ each independently represent -CO-O-, -O-CO-, -CH ₂ O-, -OCH ₂ -, -CF ₂ O-, -OCF ₂ - or -(CH ₂ ) _n -, where n is 2, 3 or 4, L is in each out At present, F, Cl, CN or a linear or branched chain having 1 to 12 C atoms, optionally or differently, may be monofluorinated or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkane Alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, preferably F, L' and L" each independently represent H, F or Cl, and r represents 0, 1, 2, 3 Or 4, s means 0, 1, 2 or 3, t means 0, 1 or 2, and x means 0 or 1.

It is especially preferred to be a compound of the formula M1 to M28.

In the compounds of formula M1 to M42 Preferred Wherein L has one of the meanings given above or below, identically or differently at each occurrence, and is preferably F, Cl, CN, NO ₂ , CH ₃ , C ₂ H ₅ , C (CH _{3 3} , CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ )C ₂ H ₅ , OCH ₃ , OC ₂ H ₅ , COCH ₃ , COC ₂ H ₅ , COOCH ₃ , COOC ₂ H ₅ , CF ₃ , OCF ₃ , OCHF ₂ , OC ₂ F ₅ or P-Sp-, excellent F, Cl, CN, CH ₃ , C ₂ H ₅ , OCH ₃ , COCH ₃ , OCF ₃ or P-Sp-, better F, Cl , CH ₃ , OCH ₃ , COCH ₃ or OCF ₃ , especially F or CH ₃ .

In addition to the polymerizable compounds described above, the LC medium according to the invention for LC displays comprises a mixture of non-polymerisable liquid crystal primordial compounds (also referred to as "host mixtures"), such non-polymerizable liquid crystal priming compounds One or more, preferably two or more, non-polymerizable liquid crystal primordial compounds are included.

In principle, any LC mixture suitable for use in conventional VA and OCB displays is suitable as the host mixture. Suitable LC mixtures are known to the person skilled in the art and are described in the literature, for example in EP 1 378 557 A1 for mixtures in VA displays and mixtures of OCB displays in EP 1 306 418 A1 and DE 102 24 046 A1. .

Suitable and preferred non-polymerizable liquid crystal primordial compounds are those non-polymerizable liquid crystal primor compounds which exhibit negative dielectric anisotropy. These compounds are especially suitable for PSA-VA displays. Further preferred embodiments are those of the following: a) LC media comprising one or more compounds of the formula CY and/or PY:

Where a represents 1 or 2, and b represents 0 or 1. Express or

R ¹ and R ² each independently represent an alkyl group having 1 to 12 C atoms, and further, one or two of the non-adjacent CH ₂ groups may be such that O atoms are not directly connected to each other via -O-, -CO-, -OCO- or -COO-substitution, preferably having an alkyl or alkoxy group of 1 to 6 C atoms, and Z ^x and Z ^y each independently represent -CH ₂ CH ₂ -, -CH= CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -CO-O-, -O-CO-, -C ₂ F ₄ -, -CF=CF-, -CH=CH-CH ₂ O- or a single bond, preferably a single bond, and L ¹ , L ² , L ³ , L ⁴ each independently represent F, Cl, OCF ₃ , CF ₃ , CH ₃ , CH ₂ F, CHF ₂ .

Preferably, both L ¹ and L ² represent F, or one of L ¹ and L ² represents F and the other represents Cl, or both L ³ and L ⁴ represent F, or L ³ and One of L ⁴ represents F and the other represents Cl.

Preferably, the CY compound is selected from the group consisting of:

Wherein a represents 1 or 2, and the alkyl group and the alkyl group * each independently represent a linear alkyl group having 1 to 6 C atoms, and (O) represents an oxygen atom or a single bond.

Preferably, the PY compound is selected from the group consisting of:

Wherein the alkyl group and the alkyl group * each independently represent a linear alkyl group having 1 to 6 C atoms, and (O) represents an oxygen atom or a single bond.

b) LC medium additionally containing one or more compounds of the formula:

Some of these groups have the following meanings: Express Express or R ³ and R ⁴ each independently represent an alkyl group having 1 to 12 C atoms, and further, one or two of the non-adjacent CH ₂ groups may be such that O atoms are not directly connected to each other via -O-, -CO-, -O-CO- or -CO-O-substitution, Z ^y represents -CH ₂ CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -CO-O-, -O-CO-, -C ₂ F ₄ -, -CF=CF-, -CH=CH-CH ₂ O- or a single bond, preferably a single bond.

The ZK compound of the formula is preferably selected from the group consisting of the following subformula:

Wherein alkyl and alkyl* each independently represent a straight-chain alkyl group having from 1 to 6 C atoms, c) an LC medium additionally comprising one or more compounds of the formula:

Wherein each individual group has the same or different meaning at each occurrence: R ⁵ and R ⁶ each independently of one another have ^one of the meanings indicated above for R ¹ , Express or Express or And e means 1 or 2.

The compound of formula DK is preferably selected from the group consisting of the following subformula:

Wherein alkyl and alkyl* each independently represent a straight-chain alkyl group having from 1 to 6 C atoms, and d) an LC medium additionally comprising one or more compounds of the formula:

Some of these groups have the following meanings: Express

f represents 0 or 1, and R ¹ and R ² each independently represent an alkyl group having 1 to 12 C atoms, and further, one or two of the non-adjacent CH ₂ groups may cause O atoms not to be directly connected to each other. The mode is replaced by -O-, -CO-, -OCO- or -COO-, and Z ^x and Z ^y each independently represent -CH ₂ CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -CO-O-, -O-CO-, -C ₂ F ₄ -, -CF=CF-, -CH=CH-CH ₂ O- or single The bond, preferably a single bond, and L ¹ and L ² each independently represent F, Cl, OCF ₃ , CF ₃ , CH ₃ , CH ₂ F, CHF ₂ .

Preferably, both L ¹ and L ² represent F, or one of the groups L ¹ and L ² represents F and the other represents Cl.

Preferably, the compound of formula LY is selected from the group consisting of:

Wherein R ¹ has the meaning indicated above, alkyl represents a linear alkyl group having 1 to 6 C atoms, (O) represents an oxygen atom or a single bond, and v represents an integer of 1 to 6. R ¹ preferably denotes a linear alkyl group having 1 to 6 C, especially CH ₃ , C ₂ H ₅ , nC ₃ H ₇ , nC ₄ H ₉ , nC ₅ H ₁₁ .

e) an LC medium additionally comprising one or more compounds selected from the group consisting of:

Wherein R ⁵ has ^one of the meanings indicated above for R ¹ , alkyl represents C _1-6 alkyl, d represents 0 or 1, and z and m each independently represent an integer from 1 to 6. R ⁵ is preferably a C _1-6 alkyl group or a C _1-6 alkoxy group in these compounds, and d is preferably 1. The LC medium according to the present invention preferably contains an amount 5% by weight of one or more compounds of the formula mentioned above.

f) an LC medium additionally comprising one or more biphenyl compounds selected from the group consisting of:

Wherein the alkyl group and the alkyl group * each independently represent a linear alkyl group having 1 to 6 C atoms, and the proportion of the biphenyl group of the formula B1 in the LC mixture is preferably at least 3% by weight, especially 5 wt%.

g) LC medium additionally containing one or more triphenyl compounds of the formula:

Wherein R ⁵ and R ⁶ each independently of one another have ^one of the meanings indicated above for R ¹ , and

Respectively independent of each other

Wherein L ⁵ represents F or Cl, preferably F, and L ⁶ represents F, Cl, OCF ₃ , CF ₃ , CH ₃ , CH ₂ F or CHF ₂ , preferably F.

The compound of formula T is preferably selected from the group consisting of:

Wherein R represents a linear alkyl group or alkoxy group having 1 to 7 C atoms, (O) represents an oxygen atom or a single bond, and m represents an integer of 1 to 6.

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

The LC medium according to the invention preferably comprises from 0.5% by weight to 30% by weight, in particular from 1% by weight to 20% by weight, of the terphenyl of the formula T and its preferred subformula.

More preferred are compounds of the formulae T1, T2, T3 and T21. In these compounds, R preferably represents an alkyl group each having 1 to 5 C atoms, more preferably an alkoxy group.

If the mixture has a Δn value 0.1, then terphenyl is preferably used in the mixture according to the invention. Preferably, the mixture comprises from 2% to 20% by weight of one or more biphenyl compounds of the formula T, preferably selected from the group of compounds T1 to T21.

h) an LC medium additionally comprising one or more compounds selected from the group consisting of:

Wherein R ¹ and R ² have the meanings indicated above, and preferably each independently represents a linear alkyl group having 1 to 6 C atoms.

Preferred media comprise one or more compounds selected from the group consisting of formulas O1, O3 and O4.

i) LC medium additionally containing one or more compounds of the formula:

among them Express R ⁹ represents H, CH ₃ , C ₂ H ₅ or nC ₃ H ₇ , (F) represents a fluorine substituent optionally selected, and q represents 1, 2 or 3, and R ⁷ has the meaning indicated for R ¹ One of them, the amount is preferably > 3% by weight, especially 5 wt% and extremely preferably 5 wt% to 30 wt%.

The preferred FI compound is selected from the group consisting of the following subtypes:

Wherein R ⁷ preferably represents a linear alkyl group, and R ⁹ represents CH ₃ , C ₂ H ₅ or nC ₃ H ₇ . Especially preferred are compounds of the formulas FI1, FI2 and FI3.

j) an LC medium additionally comprising one or more compounds selected from the group consisting of:

Wherein R ⁸ has the meaning indicated for R ¹ and alkyl represents a linear alkyl group having 1 to 6 C atoms.

k) an LC medium additionally comprising one or more compounds containing tetrahydronaphthyl or naphthyl units, for example selected from the group consisting of:

Wherein R ¹⁰ and R ¹¹ each independently have ^one of the meanings indicated for R ¹ , preferably a linear alkyl or alkoxy group having 1 to 6 C atoms, and each of Z ¹ and Z ² Independently from each other, -C ₂ H ₄ -, -CH=CH-, -(CH ₂ ) ₄ -, -(CH ₂ ) ₃ O-, -O(CH ₂ ) ₃ -, -CH=CH-CH ₂ CH ₂ -, -CH ₂ CH ₂ CH=CH-, -CH ₂ O-, -OCH ₂ -, -CO-O-, -O-CO-, -C ₂ F ₄ -, -CF=CF-, -CF=CH-, -CH=CF-, -CH ₂ - or a single bond.

l) additionally containing one or more difluorodibenzos of the formula Alkanes and / or LC medium of alkane:

Wherein R ¹¹ and R ¹² are each, and independently of one another, have the meaning indicated above, and ring M is trans-1,4-cyclohexylene or 1,4-phenylene, Z ^m -C ₂ H ₄ -, - CH ₂ O-, -OCH ₂ -, -CO-O- or -O-CO-,c is 0 or 1, preferably in an amount of from 3% by weight to 20% by weight, especially in an amount of from 3% by weight to 15% by weight .

Particularly preferred compounds of the formula BC, CR and RC are selected from the group consisting of the following subformula:

Wherein the alkyl group and the alkyl group * each independently represent a linear alkyl group having 1 to 6 C atoms, (O) represents an oxygen atom or a single bond, and c is 1 or 2.

It is especially preferred to include a mixture of one, two or three BC-2 compounds.

m) an additional LC medium containing one or more of the following fluorinated phenanthrene and/or dibenzofuran:

Wherein R ¹¹ and R ¹² each independently have the meaning indicated above, b represents 0 or 1, L represents F, and r represents 1, 2 or 3.

The compounds of the preferred formulas PH and BF are selected from the group consisting of the following subformula:

Wherein R and R' each independently represent a linear alkyl group or alkoxy group having 1 to 7 C atoms.

n) LC medium additionally containing one or more monocyclic compounds of the formula:

Wherein R ¹ and R ² each independently represent an alkyl group having 1 to 12 C atoms, and further, one or two of the non-adjacent CH ₂ groups may be such that O atoms are not directly connected to each other via -O- , -CH=CH-, -CO-, -OCO- or -COO-substitution, preferably having an alkyl or alkoxy group of 1 to 6 C atoms, and L ¹ and L ² each independently represent F, Cl , OCF ₃ , CF ₃ , CH ₃ , CH ₂ F, CHF ₂ .

Preferably, both L ¹ and L ² represent F, or one of L ¹ and L ² represents F and the other represents Cl, and the compound of formula Y is preferably selected from the group consisting of:

Wherein the alkyl group and the alkyl group * each independently represent a linear alkyl group having 1 to 6 C atoms, and the alkoxy group means a linear alkoxy group having 1 to 6 C atoms.

The Y-type Y compound is selected from the group consisting of the following sub-forms:

The alkoxy group preferably represents a linear alkoxy group having 3, 4 or 5 C atoms.

o) Except for the polymerizable compound according to the invention, an LC medium containing a compound having a blocked alkyl group (-CH=CH ₂ ) is not included.

p) comprises 1 to 5, preferably 1, 2 or 3 polymerizable compounds, preferably selected from the LC medium of the polymerizable compounds according to the invention.

q) The proportion of the polymerizable compound in the mixture is generally from 0.05% to 5%, preferably from 0.1% to 1%, of the LC medium.

r) comprises from 1 to 5, preferably 1, 2 or 3 compounds of the formula I, preferably selected from the LC medium of the compounds of the formulae A1 to C4.

The proportion of the compound of formula I in the mixture is generally from 0.05% to 5%, preferably from 0.1% to 1%, of the LC medium.

t) an LC medium comprising from 1 to 8, preferably from 1 to 5, of a compound of the formula CY, in particular a compound of the formula CY1, CY2, CY15 and/or CY16. The proportion of such compounds in the mixture is preferably from 5% to 60%, particularly preferably from 10% to 40%. In each case, the content of these individual compounds is preferably from 2% to 20%.

u) an LC medium comprising from 1 to 8, preferably from 1 to 5, of a compound of the formula PY, especially a compound of the formula PY9 and/or PY10. The proportion of such compounds in the mixture is preferably from 5% to 60%, particularly preferably from 10% to 35%. In each case, the content of these individual compounds is preferably from 2% to 20%.

v) LC medium comprising from 1 to 10, preferably from 1 to 8, compounds of the formula ZK, in particular compounds of the formula ZK1, ZK2, ZK4 and/or ZK5. The proportion of such compounds in the mixture is preferably from 3% to 50%, particularly preferably from 5% to 45%. In each case, the content of these individual compounds is preferably from 2% to 20%.

w) The proportion of the CY, PY and ZK compounds of the formula in the mixture is generally greater than 70%, preferably greater than 80% of the LC medium.

x) LC media containing one or more, preferably 1, 2 or 3, compounds of formula T2. The content of such compounds in the mixture is preferably from 1% to 20% overall.

The combination of the above-mentioned preferred embodiment of the compound with the polymeric compound described above produces a low threshold voltage, a low rotational viscosity and excellent low temperature stability in an LC medium according to the present invention while producing a constant High-definition spot and high HR values allow for the creation of particularly low pre-tilt angles in PSA displays. In particular, LC media exhibits a significantly reduced response time, especially grayscale response time, in PSA displays compared to media from prior art.

The nematic phase range of the liquid crystal mixture is preferably at least 80K, particularly preferably at least 100K, and the rotational viscosity at 20 ° C is not more than 250 mPa. s, preferably no more than 200mPa. s.

In the VA type display according to the present invention, the molecules in the LC dielectric layer in the off state are aligned (vertically) perpendicular to the electrode surface or have an oblique vertical alignment. After applying a voltage to the electrodes, realignment of the LC molecules occurs with the longitudinal molecular axes parallel to the electrode surface.

The negative dielectric anisotropy Δ ε of the LC medium according to the present invention (especially for PSA-VA type display) based on the compound having negative dielectric anisotropy according to the first preferred embodiment is preferably 20 ° C and 1 kHz. It is -0.5 to -10, especially -2.5 to -7.5.

The birefringence Δn in the LC medium according to the present invention for a PSA-VA type display is preferably less than 0.16, particularly preferably from 0.06 to 0.14, and particularly preferably from 0.07 to 0.12.

In the OCB type display according to the present invention, the molecules in the LC dielectric layer have a "bending" alignment. After application of the voltage, realignment of the LC molecules occurs with the longitudinal molecular axis perpendicular to the electrode surface.

The LC medium according to the present invention for a PSA-OCB type display is preferably an LC medium based on a compound having positive dielectric anisotropy according to the second preferred embodiment, and the positive dielectric anisotropy Δ ε is 20 It is preferably +4 to +17 at ° C and 1 kHz.

The birefringence Δn in the LC medium according to the present invention for the PSA-OCB type display is preferably from 0.14 to 0.22, particularly preferably from 0.16 to 0.22.

The LC medium according to the present invention may also contain other additives known to those skilled in the art and described in the literature, for example, polymerization initiators, inhibitors, stabilizers (as given, for example, in Table F), other surface activities. Substance or palmitic dopant.

In a preferred embodiment, the LC medium contains a preferred concentration of from 0.01% to 1%, preferably from 0.05% to 0.5%, of one or more pairs of palmitic dopants. Preferably, the palm dopant is selected from the group consisting of compounds from Table B below, preferably selected from R- or S-1011, R- or S-2011, R- or S-3011, R- or S-4011. And a group consisting of R- or S-5011.

In another preferred embodiment, the LC medium contains one or more racemic dopant racemates preferably selected from the palmitic dopants mentioned in the previous paragraph.

Further, it is possible to add, for example, 0 to 15% by weight of a polychromatic dye to the LC medium, in addition to nanoparticles, a conductive salt (preferably 4-hexyloxybenzoic acid ethyldimethyldodecyl ammonium, tetraphenyl) Tetrabutylammonium borate or crown ether complex salt) (see, for example, Haller et al, Mol. Cryst. Liq. Cryst. 24 , 249-258 (1973)) for improved conductivity; or for modification of dielectric A substance that is oriented toward the opposite sex, viscosity, and/or nematic. Substances of this type are described, for example, in DE-A 22 09 127, 22 40 864, 23 21 632, 23 38 281, 24 50 088, 26 37 430 and 28 53 728.

The LC medium which can be used according to the invention is in a manner known per se, for example by mixing one or more of the compounds mentioned above with one or more polymerizable compounds and one or more compounds of the formula I as defined above And, as appropriate, with other liquid crystal compounds and/or additives. In general, the components required in a smaller amount are advantageously dissolved in the components constituting the main component at a high temperature. It is also possible to mix a solution of the component in an organic solvent such as acetone, chloroform or methanol and, after thorough mixing, remove the solvent again, for example by distillation. Furthermore, the invention relates to a process for the preparation of an LC medium according to the invention.

It is self-evident to those skilled in the art that the LC medium according to the present invention may also comprise a compound in which, for example, H, N, O, Cl, F have been substituted with the corresponding isotopes.

The invention is described above and below by way of specific reference to preferred embodiments. It is to be understood that various changes and modifications may be made therein without departing from the spirit and scope of the invention.

Many of the compounds mentioned above and below or mixtures thereof are commercially available. Organic compounds are known or can be prepared by methods known per se, as described in the literature (for example in standard works such as Houben-Weyl, Methoden der Organischen Chemie [Methods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart). ), specifically, it is prepared under the reaction conditions known and suitable for the reactions. Variants of methods known per se but not mentioned herein may also be used herein.

Unless the context clearly indicates otherwise, the term is used herein. The plural form shall be taken to include the singular and vice versa.

Throughout this application, the parameter range includes all rational and integer values, including the specified limits of the parameter ranges and their error limits, unless otherwise explicitly stated. Other preferred embodiments are produced in combination with the stated upper and lower limits for the respective ranges.

In the embodiments of the present specification and the scope of the patent application, the words "include" (comprise) and "contain" and variations of such words, such as "comprising" and "comprises" means "including (but not limited to)" and not intended (and not Exclude other components. On the other hand, the word "include" also covers the term "consisting of" but is not limited thereto.

It will be appreciated that variations may be made to the foregoing embodiments of the invention, but such variations are still within the scope of the invention. Alternate features for the same, equivalent or similar purpose may be substituted for the features disclosed in the present specification unless otherwise stated. Therefore, unless otherwise stated, the disclosed features are only one example of a series of common equivalent or similar features.

All of the features disclosed in this specification can be combined in any combination, except at least some combinations of such features and/or steps are mutually exclusive. In particular, the preferred features of the invention are applicable to all aspects of the invention and can be used in any combination. Also, features described in non-essential combinations may be used separately (not in combination).

It will be appreciated that many of the features of the above-described preferred embodiments are inherently inventive and not only as part of an embodiment of the invention. In addition to or in lieu of any of the inventions currently claimed, independent protection may be sought for such features.

The structure of an LC display in accordance with the present invention corresponds to the common geometry of a PSA display as described in the prior art cited at the outset. A geometry without protrusions is preferred, in particular the electrodes on the side of the color filter are unstructured and only the electrodes on the side of the TFT have the geometry of the slots. Particularly suitable and preferred for PSA-VA displays The polar structure is described, for example, in US 2006/0066793 A1.

All concentrations in this application are to be taken as a percentage by weight unless otherwise specifically indicated, and are in reference to the respective <RTIgt;

All temperature values indicated in this application, such as melting point T(C,N), smectic (S) to nematic (N) phase transition T(S,N), and clear point T, unless otherwise explicitly indicated (N, I) are all quoted in degrees Celsius (°C). M.p. represents the melting point, cl.p. = clear point. Further, C = crystalline state, N = nematic phase, S = smectic phase and I = isotropic phase. The data between these symbols indicates the transfer temperature.

Unless otherwise expressly indicated in each case, all physical properties are determined or based on "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status 1997, Merck KGaA, Germany, and are suitable for temperatures up to 20 °C. And Δn was measured at 589 nm and Δε was measured at 1 kHz.

Unless specifically indicated otherwise, the terms of the present invention, "threshold voltage" system on a capacitive threshold (V _0), also known as Freedericks threshold. In an example, the optical threshold may commonly as generally about 10% relative contrast (V ₁₀₎ and quoted.

Unless otherwise stated, the method of polymerizing a polymerizable compound in a PSA display as described above and below is carried out at a temperature at which the LC medium exhibits a liquid crystal phase, preferably a nematic phase, and is preferably carried out at room temperature.

Unless otherwise stated, methods of preparing test cells and measuring their electro-optic and other characteristics are performed by methods as described below or analogous thereto.

The display for measuring the capacitance threshold voltage consists of two plane-parallel glass outer plates with a pitch of 25 μm, each of which has an electrode layer inside and an unfriction polyimine alignment layer on the top, which realizes liquid crystal The vertical edge of the molecule is aligned.

The display or test unit for measuring the tilt angle consists of two plane-parallel glass outer plates with a pitch of 4 μm, each of which has an electrode layer inside and a polyhedron at the top. An imine alignment layer in which two polyimide layers are rubbed in antiparallel to each other and achieve vertical edge alignment of liquid crystal molecules.

The polymerizable compound is polymerized in a display or test unit by irradiation with a UVA light having a defined intensity, wherein a voltage (typically 10 V to 30 V alternating current, 1 kHz) is simultaneously applied to the display. In the examples, metal halide lamps and 100 mW/cm ² strength were used for polymerization unless otherwise indicated. The intensity was measured using a standard UVA meter (a high-end Hoenle UV meter with a UVA sensor).

The tilt angle was measured by a crystal rotation experiment (Autronic-Melchers TBA-105). The low value here (i.e., the deviation from the 90° angle) corresponds to a large tilt.

The VHR value was measured as follows: 0.3% of the polymerizable monomer compound was added to the LC host mixture, and the resulting mixture was introduced into the VA-VHR test unit (unfriction, VA-polyimine alignment layer, LC layer thickness d 6 μm). The HR value was measured before and after UV exposure at 1 V, 60 Hz, 64 μs pulse after 5 minutes at 100 ° C (measuring instrument: Autronic-Melchers VHRM-105).

In the present invention and especially in the following examples, the structure of the liquid crystal primordial compound is indicated by means of an abbreviation also referred to as a prefix. In these first words, the chemical formula is abbreviated as follows using Tables A to C below.

Use the following abbreviations: (n, m, z: 1, 2, 3, 4, 5 or 6 independently of each other in each case)

Where n and m each represent an integer, and three points "..." are placeholders for other abbreviations from this table.

The following table shows illustrative structures and their respective abbreviations. These structures and abbreviations are shown to illustrate the meaning of the abbreviated rules. Furthermore, it represents a compound which is preferably used.

Table D

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

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

Table E

Table E shows possible pairs of palmitic dopants that can be added to the LC medium according to the present invention.

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

Table F

Table F shows possible stabilizers that can be added to the LC medium according to the invention.

(wherein 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).

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

Table G

Table G shows illustrative compounds useful as LC media in accordance with the present invention, preferably as reactive liquid crystal primordial compounds.

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

The following examples illustrate the invention without limiting it. However, it demonstrates to the skilled artisan the preferred mixture concept and preferred compounds to be used and their respective concentrations and their mutual combination. In addition, the examples illustrate the characteristics and combinations of features that are available.

Instance

Use the following abbreviations and symbols:

General method for producing test units

The preparation of the LCD test unit begins with standard cleaning commercial ITO coated glass sheets. Subsequently, a series of unit treatments were performed on the glass substrate, including polyimine (PI) alignment film coating, PI film thermal baking, mechanical rubbing, ball spacer spraying, and UV glue dispensing. After the lower and upper substrates are cleaned, a sealant is applied to the edge portion of the upper substrate. At this time, a sealant may be applied to the lower substrate. Thereafter, the lower substrate is introduced into the liquid crystal dispenser, and then a predetermined amount of liquid crystal is dropped onto a predetermined portion of the lower substrate, which corresponds to the display area of the LCD. Thereafter, the lower and upper substrates are introduced into the vacuum chamber, wherein the lower substrate is combined with the upper substrate due to the vacuum pressure applied thereto, and the gap formed between the lower substrate and the upper substrate is filled with the liquid crystal material. When the sealant applied to the edge of the upper substrate is cured, the LC ODF method is completed, and the unit is studied in terms of dropping dead spots.

Comparative example

The following liquid crystal mixture CM-1 was prepared. The composition and characteristics are given in the table below.

After the above procedure, the mixture was used in the test unit, and the test unit study results for the cell gap used are summarized in the table below.

Example

The following liquid crystal mixtures M1 to M5 were prepared by separately adding 0.4%-w/w of the following compound of formula I (SI1 to SI5) to liquid crystal mixture CM-1:

After the above procedure, the mixtures M1 to M5 were used in the respective test units, and the test unit study results on the cell gap are summarized in the following table.

legend:

Claims (12)

An LC medium comprising one or more non-polymerizable liquid crystal primordial compounds, one or more polymerizable liquid crystal primordial compounds, and one or more compounds of formula I, Wherein R ^a represents hydrogen or a hydrocarbon having 1 to 20 carbon atoms; R ^c represents a hydrocarbon having 1 to 20 carbon atoms; and R ^b and R ^d represent hydrogen or a hydrocarbon group having 1 to 8 carbon atoms, Z ^a Represents -O- or a single bond, and n is an integer from 0 to 10. The LC medium of claim 1, wherein the compound of the formula I is selected from the group consisting of compounds of formulas A to C, Wherein R ^a , R ^b , R ^c , R ^d and n have one of the meanings as given in claim 1 . The LC medium of claim 1 or 2, wherein the compound of the formula I is selected from the group of compounds of the formulae A1 to C4, Wherein R ^a , R ^c and n have one of the meanings given according to formula I. The LC medium according to any one of claims 1 to 3, wherein the compound of the formula I and its subformula is selected from the group consisting of wherein R ^a represents hydrogen, methyl, ethyl, methoxy, ethoxy, phenyl. A benzyl, methylphenyl or methoxyphenyl group and R ^c and n have a compound as one of the meanings given in claim 1 . The LC medium of any one of claims 1 to 4, wherein the one or more non-polymerizable liquid crystal primordial compounds are selected from the group consisting of a compound of the formula CY and/or PY. Where a represents 1 or 2, and b represents 0 or 1. Express or R ¹ and R ² each independently represent an alkyl group having 1 to 12 C atoms, and further, one or two of the non-adjacent CH ₂ groups may be such that O atoms are not directly connected to each other via -O-, -CO-, -OCO- or -COO-substitution, preferably having an alkyl or alkoxy group of 1 to 6 C atoms, Z ^x and Z ^y each independently representing -CH ₂ CH ₂ -, -CH= CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -CO-O-, -O-CO-, -C ₂ F ₄ -, -CF=CF-, -CH=CH-CH ₂ O- or a single bond, preferably a single bond, and L ¹ , L ² , L ³ , L ⁴ each independently represent F, Cl, OCF ₃ , CF ₃ , CH ₃ , CH ₂ F, CHF ₂ . The LC medium of any one of claims 1 to 5, wherein the ratio of the polymerizable compounds in the LC medium is from >0 to <5% by weight. The LC medium of any one of claims 1 to 6, wherein the ratio of the compound of the formula I in the LC medium is from >0 to <20% by weight. A method for preparing an LC medium according to any one of claims 1 to 7, which comprises mixing at least one or more non-polymerizable liquid crystal primordial compounds, one or more polymerizable liquid crystal primordial compounds, and one or more compounds of formula I The steps. A use of an LC medium according to any one of claims 1 to 7 for use in PS and PSA displays. An LC display comprising the LC medium of any one of claims 1 to 7. An LC display according to claim 10, comprising an LC unit composed of two substrates, wherein at least one of the substrates is light transmissive and at least one of the substrates has an electrode layer, and the polymerization group is included in any one of claims 1 to 7. And a layer of the LC medium of the low molecular weight component is located between the substrates, wherein the polymeric component can be polymerized by one or more of the substrates of the LC cell in the LC medium by applying a voltage A liquid crystal primordial compound is obtained by polymerization. A method for producing an LC display according to claim 10 or 11, comprising at least providing an LC medium according to any one of claims 1 to 7 by a one drop filling method on a first substrate Then, the steps of assembling the LC unit.