WO2024133361A1 - Milieu à cristaux liquides - Google Patents

Milieu à cristaux liquides Download PDF

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WO2024133361A1
WO2024133361A1 PCT/EP2023/086784 EP2023086784W WO2024133361A1 WO 2024133361 A1 WO2024133361 A1 WO 2024133361A1 EP 2023086784 W EP2023086784 W EP 2023086784W WO 2024133361 A1 WO2024133361 A1 WO 2024133361A1
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Sven Christian Laut
Hee-Kyu Lee
Minghui Yang
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Merck Patent Gmbh
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/34—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring
    • C09K19/3491—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having sulfur as hetero atom
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
    • C09K19/30—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing saturated or unsaturated non-aromatic rings, e.g. cyclohexane rings
    • C09K19/3098—Unsaturated non-aromatic rings, e.g. cyclohexene rings
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K2019/0444—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit characterized by a linking chain between rings or ring systems, a bridging chain between extensive mesogenic moieties or an end chain group
    • C09K2019/0448—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit characterized by a linking chain between rings or ring systems, a bridging chain between extensive mesogenic moieties or an end chain group the end chain group being a polymerizable end group, e.g. -Sp-P or acrylate
    • C—CHEMISTRY; METALLURGY
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
    • C09K19/10—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings
    • C09K19/12—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings at least two benzene rings directly linked, e.g. biphenyls
    • C09K2019/121—Compounds containing phenylene-1,4-diyl (-Ph-)
    • C09K2019/122—Ph-Ph
    • C—CHEMISTRY; METALLURGY
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
    • C09K19/10—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings
    • C09K19/12—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings at least two benzene rings directly linked, e.g. biphenyls
    • C09K2019/121—Compounds containing phenylene-1,4-diyl (-Ph-)
    • C09K2019/123—Ph-Ph-Ph
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
    • C09K19/30—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing saturated or unsaturated non-aromatic rings, e.g. cyclohexane rings
    • C09K19/3001—Cyclohexane rings
    • C09K19/3003—Compounds containing at least two rings in which the different rings are directly linked (covalent bond)
    • C09K2019/3004—Cy-Cy
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
    • C09K19/30—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing saturated or unsaturated non-aromatic rings, e.g. cyclohexane rings
    • C09K19/3001—Cyclohexane rings
    • C09K19/3003—Compounds containing at least two rings in which the different rings are directly linked (covalent bond)
    • C09K2019/3016—Cy-Ph-Ph
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
    • C09K19/30—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing saturated or unsaturated non-aromatic rings, e.g. cyclohexane rings
    • C09K19/3001—Cyclohexane rings
    • C09K19/3003—Compounds containing at least two rings in which the different rings are directly linked (covalent bond)
    • C09K2019/3027—Compounds comprising 1,4-cyclohexylene and 2,3-difluoro-1,4-phenylene

Definitions

  • the present invention relates to liquid-crystal (LC) media having negative dielectric anisotropy and to the use thereof for optical, electro-optical and electronic purposes, in particular in LC displays.
  • LC liquid-crystal
  • LCD liquid-crystal display
  • TN twisted nematic
  • TN LCDs have the disadvantage of a strong viewing-angle dependence of the contrast.
  • VA vertical aligned
  • the LC cell of a VA display contains a layer of an LC medium between two transparent electrodes, where the LC medium usually has a negative dielectric anisotropy.
  • the molecules of the LC layer are aligned perpendicular to the electrode surfaces (homeotropically) or have a tilted homeotropic alignment.
  • an electrical voltage to the two electrodes, a realignment of the LC molecules parallel to the electrode surfaces takes place.
  • IPS in-plane switching
  • IPS in-plane switching
  • the two electrodes are arranged on only one of the two substrates and preferably have intermeshed, comb-shaped structures.
  • an electric field which has a significant component parallel to the LC layer is thereby generated between them. This causes realignment of the LC molecules in the layer plane.
  • FFS far-field switching
  • FFS displays usually contain an LC medium with positive dielectric anisotropy, and an alignment layer, usually of polyimide, which provides planar alignment to the molecules of the LC medium.
  • FFS displays can be operated as active-matrix or passive-matrix displays.
  • active-matrix displays individual pixels are usually addressed by integrated, non-linear active elements, such as, for example, transistors (for example thin-film transistors (“TFTs”)), while in the case of passive-matrix displays, individual pixels are usually addressed by the multiplex method, as known from the prior art.
  • TFTs thin-film transistors
  • FFS displays have been disclosed (see S.H. Lee et al., Appl. Phys. Lett. 73(20), 1998, 2882-2883 and S.H. Lee et al., Liquid Crystals 39(9), 2012, 1141- 1148), which have similar electrode design and layer thickness as FFS displays but comprise a layer of an LC medium with negative dielectric anisotropy instead of an LC medium with positive dielectric anisotropy.
  • the LC medium with negative dielectric anisotropy shows a more favorable director orientation that has less tilt and more twist orientation compared to the LC medium with positive dielectric anisotropy, as a result of which these displays have a higher transmission.
  • the displays further comprise an alignment layer, preferably of polyimide provided on at least one of the substrates that is in contact with the LC medium and induces planar alignment of the LC molecules of the LC medium.
  • an alignment layer preferably of polyimide provided on at least one of the substrates that is in contact with the LC medium and induces planar alignment of the LC molecules of the LC medium.
  • These displays are also known as "Ultra Brightness FFS (UB-FFS)" mode displays. These displays require an LC medium with high reliability.
  • VA displays of the more recent type uniform alignment of the LC molecules is restricted to a plurality of relatively small domains within the LC cell. Disclinations may exist between these domains, also known as tilt domains.
  • VA displays having tilt domains have, compared with conventional VA displays, a greater viewing-angle independence of the contrast and the grey shades.
  • displays of this type are simpler to produce since additional treatment of the electrode surface for uniform alignment of the molecules in the switched-on state, such as, for example, by rubbing, is no longer necessary. Instead, the preferential direction of the tilt or pretilt angle is controlled by a special design of the electrodes.
  • MVA multidomain vertical alignment
  • the slitted electrodes generate an inhomogeneous electric field in the LC cell on application of a voltage, meaning that controlled switching is still achieved.
  • the separations between the slits and protrusions can be increased, but this in turn results in a lengthening of the response times.
  • PVA patterned VA
  • protrusions are rendered completely superfluous in that both electrodes are structured by means of slits on the opposite sides, which results in increased contrast and improved transparency to light but is technologically difficult and makes the display more sensitive to mechanical influences (“tapping”, etc.).
  • a shortening of the response times and an improvement in the contrast and luminance (transmission) of the display are demanded.
  • PS polymer sustained
  • PSA polymer sustained alignment
  • a small amount for example 0.3% by weight, typically ⁇ 1% by weight
  • the polymerisation is carried out at a temperature where the LC medium exhibits a liquid crystal phase, usually at room temperature.
  • RMs reactive mesogens
  • PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS and PS-TN displays are known.
  • the polymerisation of the RMs preferably takes place with an applied voltage in the case of PS-VA and PS-OCB displays, and with or without, preferably without, an applied voltage in the case of PS-IPS displays.
  • the PS(A) method results in a pretilt in the cell. In the case of PS-VA displays, the pretilt has a positive effect on response times.
  • a standard MVA or PVA pixel and electrode layout can be used.
  • PS- VA displays are described, for example, in EP 1 170626 A2, US 6,861 ,107, US 7,169,449, US 2004/0191428 A1, US 2006/0066793 A1 and US 2006/0103804 A1.
  • the PSA method can provide significant advantages here.
  • a shortening of the response times, which correlate with a measurable pretilt in test cells can be achieved without significant adverse effects on other parameters.
  • Another problem observed in prior art is that the use of conventional LC media in LC displays, including but not limited to displays of the PSA type, often leads to the occurrence of mura in the display, especially when the LC medium is filled in the display cell manufactured using the one drop filling (ODF) method. This phenomenon is also known as "ODF mura". It is therefore desirable to provide LC media which lead to reduced ODF mura.
  • LC media for use in PSA displays do often exhibit high viscosities and, as a consequence, high switching times.
  • LC media containing alkenyl compounds often show a decrease of the reliability and stability, and a decrease of the VHR especially after exposure to UV radiation.
  • the photo- polymerisation of the RMs in the PSA display is usually carried out by exposure to UV radiation, which may cause a VHR drop in the LC medium.
  • the invention is based on the object of providing novel suitable LC media, which do not have the disadvantages indicated above or do so to a reduced extent.
  • liquid crystalline media with a suitably high negative As, a suitable phase range and An and high LTS can be realized which do not exhibit the drawbacks of the materials of the prior art or at least do exhibit them to a significantly lesser degree by using liquid crystalline media comprising one or more compounds of formula I defined below.
  • the invention relates to a liquid crystal medium comprising a) one or more compounds of the formula I in which
  • R 1 and R 2 identically or differently, denote H, halogen, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl or alkenyloxy each having 3 to 15 C atoms, where one or more CH2 groups in these radicals may each be replaced,
  • L 11 and L 12 each, independently of one another, denote F, Cl, CF 3 or CHF 2 ,
  • L 13 and L 14 each, independently of one another, denote H, F, Cl, CF 3 or CHF 2 ,
  • Y 1 denotes H, F, Cl, CF 3 , CHF 2 or CH 3 , and n is 0 or 1 , preferably 1 ; and b) one or more compounds selected from the group of compounds of the formulae
  • R 2A , R 2B , R 2C and R 2D identically or differently, denote H, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl, alkenyloxy each having 3 to 15 C atoms, where one or more CH2 groups in these radicals may each be
  • L 1 , L 2 , L 3 and L 4 each, independently of one another, denote F, Cl, CF 3 or CHF 2 ,
  • Y denotes H, F, Cl, CF 3 , CHF 2 or CH 3 ,
  • P denotes 0, 1 or 2
  • q denotes 0 or 1
  • v denotes an integer from 1 to 6.
  • the invention furthermore relates to a process for preparing an LC medium as described above and below, comprising the steps of mixing one or more compounds of the formula I with one or more compounds of the formulae HA, 11 B, IIC and/or IID, and optionally with one or more chiral dopants, and optionally with one or more polymerisable compounds and optionally with further LC compounds and/or additives.
  • the invention furthermore relates to the use of the LC media according to the invention for electro-optical purposes, preferably in displays, very preferably in displays of the VA, IPS or FFS type, in particular of the LIB-FFS type.
  • the invention furthermore relates to the use of the LC media according to the invention in PSA displays, in particular to the use in PSA displays containing an LC medium, for the production of a tilt angle in the LC medium by in-situ polymerisation of polymerisable reactive mesogens (RM) in the PSA display, preferably in an electric or magnetic field.
  • RM polymerisable reactive mesogens
  • the invention furthermore relates to an LC display comprising an LC medium according to the invention, in particular a VA, IPS, FFS or UB-FFS or PSA display, particularly preferably an FFS, UB-FFS, VA or a PS-VA display.
  • an LC display comprising an LC medium according to the invention, in particular a VA, IPS, FFS or UB-FFS or PSA display, particularly preferably an FFS, UB-FFS, VA or a PS-VA display.
  • the invention furthermore relates to the use of LC media according to the invention in polymer stabilised SA-VA displays, and to a polymer stabilised SA-VA display comprising the LC medium according to the invention.
  • an energy saving display for gaming comprising the liquid crystal medium defined above and below.
  • the medium for the energy saving display for gaming has a birefringence in the range of from 0.125 to 0.155.
  • the invention furthermore relates to a process for manufacturing an LC display as described above and below, comprising the steps of filling or otherwise providing an LC medium, which optionally comprises one or more polymerisable compounds as described above and below, between the substrates of the display, and optionally polymerising the polymerisable compounds.
  • the LC media according to the invention show the following advantageous properties, in particular when used in FFS displays:
  • LC media comprising the compounds of formula I in which Y 1 denotes H or methyl, preferably H, L 11 and L 12 denote F, L 13 and L 14 denote H and R 1 and R 2 have the meanings defined above for formula I. Very preferably n is 1 .
  • More preferred compounds of the formula I are selected from the compounds of the formulae la, lb, Ic, Id and le, very preferably of the formula lb: in which R 1 and R 2 , identically or differently, denote straight chain alkyl having 1 to 15
  • Preferred compounds of the formula la are selected from the compounds of the formulae la-1 to la-36. in which v is an integer from 1 to 6.
  • Preferred compounds of the formula lb are selected from the compounds of the formulae lb-1 to lb-36.
  • v is an integer from 1 to 6.
  • Preferred compounds of the formula Ic are selected from the compounds of the formulae lc-1 to lc-36. in which v is an integer from 1 to 6.
  • Preferred compounds of the formula Id are selected from the compounds of the formulae Id-1 to Id-36.
  • v is an integer from 1 to 6.
  • Preferred compounds of the formula le are selected from the compounds of the formulae le-1 to le-36. in which v is an integer from 1 to 6.
  • Preferred compounds of the formulae HA, I IB, IIC and HD are indicated below: in which the parameter a denotes 1 or 2, alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, and alkenyl denotes a straight-chain alkenyl radical having 2-6 C atoms, and (O) denotes an oxygen atom or a single bond.
  • Very preferred compounds of the formula HD are selected from the following sub- formulae:
  • the medium comprises one or more compounds of formula 11 D-10a in which the occurring groups and parameters have the meanings given above under formula HD, and
  • R 2 denotes , j n which r is 0, 1 , 2, 3, 4, 5 or 6 and s is 1 , 2 or 3.
  • Preferred compounds of formula IID-10a are the compounds IID-10a-1 to IID-10a- 14.
  • Particularly preferred mixtures according to the invention comprise one or more compounds of the formulae IIA-2, IIA-8, IIA-10, IIA-16, IIA-18, IIA-40, IIA-41 , IIA-42, IIA-43, IIB-2, IIB-10, IIB-16, IIC-1 , IID-4 and IID-10.
  • Preferred media according to the invention comprise at least one compound of the formula IIC-1 , in which alkyl and alkyl* have the meanings indicated above.
  • the medium comprises one or more compounds of the formula IIA-2 selected from the following sub-formulae:
  • the medium comprises one or more compounds of the formulae I IA-2a- 1 to IIA- 2a-5:
  • the medium comprises one or more compounds of the formula IIA-10 selected from the following sub-formulae:
  • the medium comprises one or more compounds of the formulae I IA-10a-1 to
  • IIA-10a-5 IIA-10a-5
  • the medium comprises one or more compounds of the formula IIB-10 selected from the following sub-formulae:
  • the medium comprises one or more compounds of the formulae I IB-10a-1 to IIB-10a-5:
  • the medium according to the invention preferably comprises one or more compounds of formula III in which
  • R 31 and R 32 each, independently of one another, denote H, an alkyl or alkoxy radical having 1 to 15 C atoms, where one or more CH2 groups in these radicals may each be replaced, independently of one another, by
  • a 31 on each occurrence independently denotes a) 1 ,4-cyclohexenylene or 1 ,4-cyclohexylene radical, in which one or two non- adjacent CH2 groups may be replaced by -O- or -S-, b) a 1 ,4-phenylene radical, in which one or two CH groups may be replaced by N, or c) a radical from the group spiro[3.3]heptane-2,6-diyl, 1 ,4-bicyclo[2.2.2]- octylene, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1 , 2,3,4- tetrahydronaphthalene-2
  • L 31 and L 32 each, independently of one another, denote F, Cl, CF3 or CHF2, preferably H or F, most preferably F, and
  • W denotes O or S.
  • the compounds of formula III are preferably selected from the compounds of the formula 111-1 and/or III-2 in which the occurring groups have the same meanings as given under formula III above and preferably
  • R 31 and R 32 each, independently of one another, an alkyl, alkenyl or alkoxy radical having up to 15 C atoms, more preferably one or both of them denote an alkoxy radical and L 31 and L 32 each preferably denote F.
  • the compounds of the formula 111-1 are selected from the group of compounds of the formulae 111-1-1 to 111-1-1 1 , preferably of formula 111-1-6, alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms, alkoxy and alkoxy* each, independently of one another, denote a straight-chain alkoxy radical having 1-6 C atoms, and L 31 and L 32 each, independently of one another, denote F or Cl, preferably both F.
  • the compounds of the formula HI-2 are selected from the group of compounds of the formulae 111-2-1 to 111-2-10, preferably of formula III-2-6, in which alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms, alkoxy and alkoxy* each, independently of one another, denote a straight-chain alkoxy radical having 1-6 C atoms, and L 31 and L 32 each, independently of one another, denote F or Cl, preferably both F.
  • the medium comprises one or more compounds of the formula IIIA-1 and/or IIIA-2 in which L 31 and L 32 have the same meanings as given under formula III, (O) denotes O or a single bond,
  • R IIIA denotes alkyl or alkenyl having up to 7 C atoms or a group Cy-C m H2m+i-, m and n are, identically or differently, 0, 1 , 2, 3, 4, 5 or 6, preferably 1 , 2 or 3, very preferably 1 ,
  • Cy denotes a cycloaliphatic group having 3, 4 or 5 ring atoms, which is optionally substituted with alkyl or alkenyl each having up to 3 C atoms, or with halogen or CN, and preferably denotes cyclopropyl, cyclobutyl, cyclopentyl, cyclopent- 1-enyl, cyclopent-2-enyl and cyclopent-3-enyl.
  • the compounds of formula IIIA-1 and/or IIIA-2 are contained in the medium either alternatively or in addition to the compounds of formula III, preferably additionally.
  • IIIA-1 and IIIA-2 are the following: IIIA-2-3 alkoxy
  • alkoxy denotes a straight-chain alkoxy radical having 1-6 C atoms or alternatively -(CH2) n F in which n is 2,3,4, or 5, preferably C2H4F.
  • the medium comprises one or more compounds of formula HI-3
  • R 31 , R 32 identically or differently, denote H, an alkyl or alkoxy radical having 1 to
  • the compounds of formula III-3 are preferably selected from the group of compounds of the formulae 111-3-1 to 111-3-10:
  • R 32 denotes alkyl having 1 to 7 C-atoms, preferably ethyl, n-propyl or n- butyl, or alternatively cyclopropylmethyl, cyclobutyl methyl or cyclopentylmethyl or alternatively -(CH 2 ) n F in which n is 2,3,4, or 5, preferably C2H4F.
  • the medium comprises one or more compounds of the formulae 111-4 to 111-6, preferably of formula 111-5, in which the parameters have the meanings given above, R 31 preferably denotes straight-chain alkyl and R 32 preferably denotes alkoxy, each having 1 to 7 C atoms.
  • the medium comprises one or more compounds of the formula III selected from the group of compounds of formulae 111-7 to 111-9, preferably of formula 111-8,
  • R 31 preferably denotes straight-chain alkyl and R 32 preferably denotes alkoxy each having 1 to 7 C atoms.
  • the medium comprises one or more compounds of the
  • R 41 denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms, preferably an n-alkyl radical, particularly preferably having 2, 3, 4 or 5 C atoms, and
  • R 42 denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkoxy radical having 1 to 6 C atoms, both preferably having 2 to 5 C atoms, an unsubstituted alkenyl radical having 2 to 7 C atoms, preferably having 2, 3 or 4 C atoms, more preferably a vinyl radical or a 1 -propenyl radical and in particular a vinyl radical.
  • the compounds of the formula IV are preferably selected from the group of the compounds of the formulae IV-1 to IV-4, IV-1 in which alkyl and alkyl’, independently of one another, denote alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms, alkenyl denotes an alkenyl radical having 2 to 5 C atoms, preferably having 2 to 4 C atoms, particularly preferably 2 C atoms, alkenyl’ denotes an alkenyl radical having 2 to 5 C atoms, preferably having 2 to 4 C atoms, particularly preferably having 2 to 3 C atoms, and alkoxy denotes alkoxy having 1 to 5 C atoms, preferably having 2 to 4 C atoms.
  • the compounds of the formula IV-1 are preferably selected from the group of the compounds of the formulae IV-1-1 to IV-1-5
  • the compounds of the formula IV-2 are preferably selected from the compounds of the formulae IV-2-1 and IV-2-2
  • the compounds of the formula IV-3 are preferably selected from the group of the compounds of the formulae IV-3-1 and IV-3-2: in which alkyl has the meanings defined above.
  • the compounds of the formula IV-3-1 and IV-3-2 are preferably selected from the following compounds:
  • the medium according to the invention comprises a compound of formula IV-4, in particular selected from the compounds of the formulae IV-4-1 to IV-4-3
  • the medium according to the invention comprises one or more compounds of formula I selected from the compounds of the formulae 1-1 to I-4 in combination with one or more compounds selected from the group of compounds of the formulae I A- 1 to IA-9: in which alkyl denotes methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or n- pentyl.
  • the liquid-crystalline medium preferably additionally comprises one or more compounds of the formula IVa, in which R 41 and R 42 each, independently of one another, denote a straight-chain alkyl, alkoxy, alkenyl, alkoxyalkyl or alkoxy radical having up to 12 C atoms, and
  • alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1 to 6 C atoms.
  • the medium according to the invention preferably comprises at least one compound of the formula IVa-1and/or formula IVa-2.
  • the proportion of compounds of the formula IVa in the mixture as a whole is preferably less than 5 % by weight, very preferably less than 2% by weight.
  • the medium comprises one or more compounds of formula IVb-1 to
  • alkyl and alkyl* each, independently of one another denote a straight-chain alkyl radical having 1 to 6 C atoms
  • alkenyl and alkenyl* each, independently of one another denote a straight-chain alkenyl radical having 2 to 6 C atoms.
  • IVb-2 are particularly preferred.
  • biphenyls are IVb-2-4 in which alkyl* denotes an alkyl radical having 1 to 6 C atoms and preferably denotes n-propyl.
  • the medium according to the invention particularly preferably comprises one or more compounds of the formulae IVb-1-1 and/or IVb-2-3.
  • the medium according to the invention comprises one or more compounds of formula V in which
  • R 51 , R 52 denote alkyl having 1 to 7 C atoms, alkoxy having 1 to 7 C atoms, or alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7 C atoms,
  • the compounds of formula V are preferably selected from the compounds of the formulae V-1 to V-16: in which R 51 and R 52 have the meanings indicated for formula V above.
  • R 51 and R 52 preferably each, independently of one another, denote straight-chain alkyl having 1 to 7 C atoms or alkenyl having 2 to 7 C atoms.
  • Preferred media comprise one or more compounds of the formulae V-1 , V-5, V-6, V-8, V-9, V-10, V-11 , V-12, V-14, V-15, and/or V-16, very preferably V-5 or V-6.
  • the medium according to the invention comprises one or more compounds of the formula CL in which
  • R L denotes H, a straight chain or branched alkyl or alkoxy radical having 1 to 15 C atoms, or a straight chain or branched alkenyl radical having 2 to 15 C atoms, where one or more CH2 groups in these radicals may each be replaced, independently of such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by halogen,
  • X L denotes F, Cl, CN, CHF2, CF3, OCF3, or, identically or differently, has one of the meanings of R L ,
  • Y L denotes H, F, Cl or CH3.
  • the compounds of formula CL are preferably selected form the group of compounds of the formulae CL-1 , CL-2 and CL-3: in which
  • R L1 and R L2 identically or differently, have the meanings given above for formula I and, preferably denote alkyl or alkenyl having 1 to 7 C atoms or 2 to 7 C atoms, respectively, in which a CH2 group may be replaced by cyclopropane- 1 , 2-diyl, and R L2 alternatively denotes alkoxy having 1 to 5 C atoms.
  • Very preferred compounds of the formula I are selected from the compounds of the formulae CL-3-1 to CL-3-12:
  • the medium according to the invention comprises the compound CL-3-1.
  • the medium additionally comprises one or more compounds of the formulae VI-1 to VI-21, preferably of the formula VI-4.
  • R 6 denotes a straight-chain alkyl or alkoxy radical having 1 to 6 C atoms
  • (O) denotes -O- or a single bond
  • m is 0, 1 , 2, 3, 4, 5 or 6
  • n is 0, 1 , 2, 3 or 4.
  • R preferably denotes methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentoxy.
  • (O) preferably denotes -O-.
  • the medium additionally comprises one or more compounds of the formulae VI 1-1 to VII-9
  • R 7 denotes a straight-chain alkyl or alkoxy radical having 1 to 6 C atoms, or a straight chain alkenyl radical having 2 to 6 C atoms, and w is an integer from 1 to 6.
  • the medium according to the invention comprises one or more compounds of the formula VIII: in which
  • R 81 and R 82 identically or differently, denote H, halogen, CN, SCN, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl or alkenyloxy having 3 to 15 C atoms, where one or more CH2 groups in these radicals may each be replaced,
  • R 83 denotes H, straight chain alkyl or alkoxy each having 1 to 10 C atoms, straight chain alkenyl or alkenyloxy each having 2 to 10 C atoms, or cyclopropyl, preferably H, methyl or ethyl, very preferably H or methyl, in particular H, A°, A 81 , and A 82 , each, independently of one another, denote phenylene-1 ,4-diyl, in which one or two CH groups may be replaced by N and one or more H atoms may be replaced by halogen, CN, CH3, CHF2, CH2F, CF3, OCH3, OCHF2 or OCF3, cyclohexane-1 ,4-diyl, in which one or two non-adjacent CH2 groups may be replaced, independently of one another, by O and/or S and one or more H atoms may be replaced by F, cyclohexene-1 ,4-diyl, bicyclo[
  • a 81 and A 82 in formula I preferably denote phenylene-1 ,4-diyl, which may also be mono- or polysubstituted by F, furthermore cyclohexane-1 ,4-diyl, cyclohexenylene-
  • Z 81 and Z 82 in formula I preferably denote -CF2O-, -OCF2- or a single bond, very preferably a single bond.
  • L denotes halogen, CF3 or CN, preferably F.
  • R 81 and R 82 each, independently of one another, denote H, F, or alkyl, alkoxy, alkenyl or alkynyl having 1 to 8, preferably 1 to 5, C atoms, each of which is optionally substituted by halogen, in particular by F.
  • R 81 and R 82 preferably denote H, optionally fluorinated alkyl or alkoxy having 1 to 7 C atoms, optionally fluorinated alkenyl or alkynyl having 2 to 7 C atoms, optionally fluorinated cycloalkyl having 3 to 12 C atoms.
  • R 81 and R 82 are not H, particularly preferably both of R 81 and R 82 are not H.
  • R 81 is very particularly preferably alkyl.
  • R 82 is furthermore preferably H, alkyl or fluorine.
  • R 81 is alkyl and R 82 is H or alkyl.
  • R 81 , R 82 each, independently of one another, very particularly preferably denote unbranched alkyl having 1 to 5 C atoms. If R 81 and R 82 denote substituted alkyl, alkoxy, alkenyl or alkynyl, the total number of C atoms in the two groups R 81 and R 82 is preferably less than 10.
  • Preferred compounds of the formula VIII are selected from the following sub- formulae, more preferably from the compounds of the formula VI 11-3: in which R 81 , R 82 and R 83 have the meanings indicated above, and r, s and t independently are 0, 1 , 2, 3, or 4. r preferably is 1 or 2, very preferably 2 and s and t independently are preferably 0 or 1 , very preferably 0. R 81 and R 82 in particular independently denote n-alkyl having 1 to 5 C atoms.
  • the compounds of the formulae VII 1-1 to VIII-6 are selected from the compounds of the formula VI 11-1 a to VII l-6a, in particular of the formula VI ll-3a: in which R 81 , R 82 , R 83 , r and s have the meanings defined above.
  • the compounds of the formulae VIII-1 to VIII-6 are selected from the compounds of the formula VI 11- 1b to Vlll-5b, in particular of the formula VI I l-2b: in which R 81 , R 82 , R 83 , r and s have the meanings defined above.
  • the compounds of the formulae VII 1-1 to VIII-6 are selected from the compounds of the formula VI 11-1 c to VI ll-6c, in particular of the formula 13-c: in which R 81 , R 82 , R 83 , r and s have the meanings defined above.
  • the compounds of the formulae VI 11-1 to VIII- 6 are selected from the compounds of the formula VI 11-1 d to VI I l-6d, in particular of the formula VI I l-3d: in which R 81 , R 82 , R 83 , r and s have the meanings defined above.
  • the medium according to the invention comprises one or more compounds selected from the group of the formulae VI 11-1 a to VII l-6a and one or more compounds selected from the group of the formulae VIII- 1b to Vlll-6b.
  • the medium comprises one or more compounds selected from the group of compounds of the formulae VII l-3a, VI ll-2b, VII l-3c and VII l-3d: in which R 81 , R 82 , R 83 , r and s have the meanings defined above, and preferably r is 0.
  • the medium according to the invention comprises one or more compounds of the formula IX in which
  • R 91 and R 92 identically or differently, denote H, halogen, straight chain alkyl or alkoxy having 1 to 15 C atoms, straight chain alkenyl or alkenyloxy having 2 to 15 C atoms or branched alkyl, alkoxy, alkenyl or alkenyloxy each having 3 to 15 C atoms, where one or more CH2 groups in these radicals may each be replaced,
  • L 91 and L 92 each, independently of one another, denote F, Cl, CF 3 or CHF 2 ,
  • L 93 and L 94 each, independently of one another, denote H, F, Cl, CF3 or CHF2,
  • Y denotes H, F, Cl, CF3, CHF2 or CH3, preferably H or CH3, very preferably H, and n is 0 or 1 , preferably 0.
  • Very preferred compounds of the formula IX are selected from the compounds of the formulae IX- 1 to IX-35
  • Liquid-crystalline medium comprising at least one compound of the formulae Z-1 to Z-7, in which R and alkyl have the meanings indicated above for formula III.
  • Preferred liquid-crystalline media according to the invention comprise one or more substances which contain a tetrahydronaphthyl or naphthyl unit, such as, for example, the compounds of the formulae N-1 to N-5,
  • R 1 N and R 2N each, independently of one another, have the meanings indicated for R 2A , preferably denote straight-chain alkyl, straight-chain alkoxy or straight-chain alkenyl, and
  • Preferred mixtures comprise one or more compounds selected from the group of the difluorodibenzochroman compounds of the formula BC, chromans of the formula CR, and fluorinated phenanthrenes of the formulae PH-1 and PH-2, in which R B1 , R B2 , R CR1 , R CR2 , R 1 , R 2 each, independently of one another, have the meaning of R 2A .
  • c is 0, 1 or 2.
  • R 1 and R 2 preferably, independently of one another, denote alkyl or alkoxy having 1 to 6 C atoms.
  • Particularly preferred compounds of the formulae BC and CR are the compounds BC-1 to BC-7 and CR-1 to CR-5, in which alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1 to 6 C atoms, and alkenyl and alkenyl* each, independently of one another, denote a straight- chain alkenyl radical having 2 to 6 C atoms.
  • mixtures comprising one, two or three compounds of the formula BC-2 and/or BC-3.
  • Preferred mixtures comprise one or more indane compounds of the formula In, in which
  • R 11 , R 12 , and R 13 each, independently of one another, denote a straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl radical having 1 to 6 C atoms,
  • R 12 and R 13 alternatively denote halogen, preferably F, i denotes 0, 1 or 2.
  • Preferred compounds of the formula In are the compounds of the formulae In-
  • Preferred mixtures additionally comprise one or more compounds of the formulae L-1 to L-5, in which
  • R, R 1 and R 2 each, independently of one another, have the meanings indicated for R 2A in formula HA above, and alkyl denotes an alkyl radical having 1 to 6 C atoms.
  • the parameter s denotes 1 or 2.
  • the compounds of the formulae L-1 to L-9 are preferably employed in concentrations of 5 to 15 % by weight, in particular 5 to 12 % by weight and very particularly preferably 8 to 10 % by weight.
  • Preferred mixtures additionally comprise one or more compounds of formula IIA-
  • Preferred compounds of the formula IIA-Y are selected from the group consisting of the following sub-formulae in which, Alkyl and Alkyl* each, independently of one another, denote a straight- chain alkyl radical having 1-6 C atoms, Alkoxy denotes a straight-chain alkoxy radical having 1-6 C atoms, Alkenyl and Alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms, and O denotes an oxygen atom or a single bond.
  • Particularly preferred compounds of the formula IIA-Y are selected from the group consisting of following sub-formulae: in which Alkoxy and Alkoxy* have the meanings defined above and preferably denote methoxy, ethoxy, n-propyloxy, n-butyloxy or n-pentyloxy.
  • the medium according to the invention comprises a compound selected from the group of compounds of the formulae ST-1 to ST-18, very preferably of the formula ST-3: in which
  • R ST denotes H, an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH 2 groups in these radicals may each be replaced,
  • L 1 and L 2 each, independently of one another, denote F, Cl, CH 3 , CF 3 or CHF 2 , p denotes 0, 1 or 2, q denotes 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.
  • n preferably denotes 3.
  • n preferably denotes 7.
  • Very particularly preferred mixtures according to the invention comprise one or more stabilizers from the group of the compounds of the formulae ST-2a-1 , ST-3a-1 , ST-
  • the medium comprises one or more compounds of the formula S in which
  • Ar denotes a methylene group or an aromatic hydrocarbon group having 6 to 40 C atoms or a heteroaromatic hydrocarbon group having 4 to 40 C atoms; preferably an aromatic hydrocarbon group having 6 to 40 C atoms;
  • Sp denotes a spacer group
  • R s denotes H, alkyl having 1 to 12 C atoms or alkenyl having 2 to 12 C atoms;
  • Z s denotes -O-, -C(O)O-, -(CH2)z- or -(CH2) Z O-, or a single bond;
  • R H denotes H, O’, CH 3 , OH or OR S ;
  • R S1 , R S2 , R S3 and R S4 identically or differently, denote alkyl having 1 to 6 C atoms, preferably having 1 to 3 C atoms, very preferably CH 3 ;
  • G denotes H or R s or a group Z S -HA; z is an integer from 1 to 6, and q is 2, 3 or 4, preferably 3 or 4.
  • Preferred aryl groups are benzene, naphthalene, anthracene, biphenyl, m-terphenyl, p-terphenyl, and (phenylalkyl)benzene in which alkyl is straight chain alkyl having 1 to 12 C atoms.
  • the medium according to the invention comprises a compound of the formula S in which the parameter q is 3 and G denotes a group Z S -HA.
  • the medium according to the invention comprises a compound of the formula S in which the parameter q is 4 and G denotes H or R s .
  • the compounds of formula S are preferably selected from the compounds of the formulae S-1, S-2 and S-3:
  • R H has the meanings given above and preferably denotes H or O, Sp on each occurrence, identically or differently, denotes a spacer group, and W denotes linear or branched, optionally unsaturated alkylene having 1 to 12 C atoms, in which one or more non-adjacent -CH2- groups may be replaced with -O-.
  • Preferred compounds of formula S-1 are selected from the compounds of the formula S-1-1 : in which R H has the meanings given above and preferably denotes H or O’, and n is an integer from 0 to 12, preferably 5, 6, 7, 8 or 9, very preferably 7.
  • Preferred compounds of formula S-2 are selected from the compounds of the formula S-2-1 : in which R H has the meanings given above and preferably denotes H or O, and n2, on each occurrence identically or differently, preferably identically, is an integer from 1 to 12, preferably 2, 3, 4, 5, or 6, very preferably 3, and R s on each occurrence identically or differently, preferably identically, denotes alkyl having 1 to 6 C atoms, preferably n-butyl.
  • Preferred compounds of formula S-3 are selected from the compounds of the formula S-3-1: in which R H has the meanings given above and preferably denotes H or O, and n is an integer from 0 to 12, preferably 5, 6, 7, 8 or 9, very preferably 7.
  • the compounds of the formulae S and ST-1 to ST-18 are preferably each present in the liquid-crystal mixtures according to the invention in amounts of 0.005 - 0.5%, based on the mixture.
  • the concentration correspondingly increases to 0.01 - 1% in the case of two compounds, based on the mixtures.
  • the total proportion of the compounds of the formulae S and ST-1 to ST- 18, based on the mixture according to the invention, should not exceed 2%.
  • liquid crystal medium according to the invention herein also referred to as liquid crystal host mixture, is suitable for the use in polymer stabilised displays.
  • the medium according to the invention optionally comprises one or more polymerisable compounds of formula P P-Sp-A 1 -(Z 1 -A 2 ) z -R P in which independently of each other and on each occurrence identically or differently,
  • P denotes a polymerisable group
  • Sp denotes a spacer group or a single bond
  • a 1 , A 2 denote an aromatic, heteroaromatic, alicyclic or heterocyclic group, preferably having 4 to 25 ring atoms, which may also contain fused rings, and which is unsubstituted, or mono- or polysubstituted by L,
  • R°, R 00 denote H or alkyl having 1 to 12 C atoms
  • R denotes H, L, or P-Sp-,
  • L denotes F, Cl, -CN, P-Sp- or straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH 2 -groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by P-Sp-, F or Cl, z is 0, 1 , 2 or 3, and n1 is 1 , 2, 3 or 4.
  • the term "reliability” as used herein means the quality of the performance of the display during time and with different stress loads, such as light load, temperature, humidity, voltage, and comprises display effects such as image sticking (area and line image sticking), mura, yogore etc. which are known to the skilled person in the field of LC displays.
  • VHR voltage holding ration
  • a high VHR is a prerequisite for a high reliability of the LC medium.
  • PSA is used hereinafter when referring to displays of the polymer sustained alignment type in general, and the term “PS” is used when referring to specific display modes, like PS-VA, PS-TN and the like.
  • active layer and “switchable layer” mean a layer in an electrooptical display, for example an LC display, that comprises one or more molecules having structural and optical anisotropy, like for example LC molecules, which change their orientation upon an external stimulus like an electric or magnetic field, resulting in a change of the transmission of the layer for polarized or unpolarized light.
  • the tilt angle here denotes the average angle ( ⁇ 90°) between the longitudinal molecular axes of the LC molecules (LC director) and the surface of the plane-parallel outer plates which form the LC cell.
  • ⁇ 90° the average angle
  • a low value for the tilt angle i.e., a large deviation from the 90° angle
  • tilt angle values disclosed above and below relate to this measurement method.
  • reactive mesogen and "RM” will be understood to mean a compound containing a mesogenic or liquid crystalline skeleton, and one or more functional groups attached thereto which are suitable for polymerisation and are also referred to as “polymerisable group” or "P".
  • polymerisable compound as used herein will be understood to mean a polymerisable monomeric compound.
  • the term "low-molecular-weight compound” will be understood to mean to a compound that is monomeric and/or is not prepared by a polymerisation reaction, as opposed to a "polymeric compound” or a “polymer”.
  • the term “unpolymerisable compound” will be understood to mean a compound that does not contain a functional group that is suitable for polymerisation under the conditions usually applied for the polymerisation of the RMs.
  • mesogenic group as used herein is known to the person skilled in the art and described in the literature, and means a group which, due to the anisotropy of its attracting and repelling interactions, essentially contributes to causing a liquid- crystal (LC) phase in low-molecular-weight or polymeric substances.
  • Compounds containing mesogenic groups do not necessarily have to have an LC phase themselves. It is also possible for mesogenic compounds to exhibit LC phase behaviour only after mixing with other compounds and/or after polymerisation. Typical mesogenic groups are, for example, rigid rod- or disc- shaped units.
  • optically active and “chiral” are synonyms for materials that are able to induce a helical pitch in a nematic host material, also referred to as “chiral dopants”.
  • spacer group above and below also referred to as “Sp”, as used herein is known to the person skilled in the art and is described in the literature, see, for example, Pure Appl. Chem. 2001 , 73(5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368.
  • spacer group or “spacer” mean a flexible group, for example an alkylene group, which connects the mesogenic group and the polymerisable group(s) in a polymerisable mesogenic compound.
  • a spacer group connects a central hydrocarbon group with a photoactive, stabilising hindered amine functional group.
  • organic group denotes a carbon or hydrocarbon group.
  • hydrocarbon group denotes a carbon group which additionally contains one or more H atoms and optionally one or more heteroatoms, such as, for example, N, O, S, B, P, Si, Se, As, Te or Ge.
  • Halogen denotes F, Cl, Br or I, preferably F or Cl.
  • a carbon or hydrocarbon group can be a saturated or unsaturated group.
  • Unsaturated groups are, for example, aryl, alkenyl or alkynyl groups.
  • a carbon or hydrocarbon radical having more than 3 C atoms can be straight-chain, branched and/or cyclic and may also contain spiro links or condensed rings.
  • alkyl also encompass polyvalent groups, for example alkylene, arylene, heteroarylene, etc.
  • aryl denotes an aromatic carbon group, or a group derived therefrom.
  • heteroaryl denotes “aryl” as defined above, containing one or more heteroatoms, preferably selected from N, O, S, Se, Te, Si and Ge.
  • Preferred carbon and hydrocarbon groups are optionally substituted, straight-chain, branched or cyclic, alkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy having 1 to 40, preferably 1 to 20, very preferably 1 to 12, C atoms, optionally substituted aryl or aryloxy having 5 to 30, preferably 6 to 25, C atoms, or optionally substituted alkylaryl, arylalkyl, alkylaryloxy, arylalkyloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy having 5 to 30, preferably 6 to 25, C atoms, wherein one or more C atoms may also be replaced by hetero atoms, preferably selected from N, O, S, Se, Te, Si and Ge.
  • hetero atoms preferably selected from N, O, S, Se, Te, Si
  • carbon and hydrocarbon groups are C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C3-C20 allyl, C4-C20 alkyldienyl, C4-C20 polyenyl, C6-C20 cycloalkyl, C4- C15 cycloalkenyl, C6-C30 aryl, Ce-Cso alkylaryl, C6-C30 arylalkyl, C6-C30 alkylaryloxy, C6-C30 arylalkyloxy, C2-C30 heteroaryl, C2-C30 heteroaryloxy.
  • C1-C12 alkyl Particular preference is given to C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C6-C25 aryl and C2-C25 heteroaryl.
  • R x preferably denotes H, F, Cl, CN, a straight-chain, branched or cyclic alkyl chain having 1 to 25 C atoms, in which, in addition, one or more non-adjacent C atoms may be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- and in which one or more H atoms may be replaced by F or Cl, or denotes an optionally substituted aryl or aryloxy group with 6 to 30 C atoms, or an optionally substituted heteroaryl or heteroaryloxy group with 2 to 30 C atoms.
  • Preferred alkyl groups are, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl, s-pentyl, cyclopentyl, n-hexyl, cyclohexyl, 2-ethylhexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, dodecanyl, trifluoromethyl, perfluoro-n-butyl, 2,2,2- trifluoroethyl, perfluorooctyl, perfluorohexyl, etc.
  • Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, etc.
  • Preferred alkynyl groups are, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, octynyl, etc.
  • Preferred alkoxy groups are, for example, methoxy, ethoxy, 2-methoxyethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy, 2-methylbutoxy, n-pentoxy, n-hexoxy, n-heptoxy, n-octoxy, n-nonoxy, n-decoxy, n-undecoxy, n-dodecoxy, etc.
  • Preferred amino groups are, for example, dimethylamino, methylamino, methylphenylamino, phenylamino, etc.
  • Aryl and heteroaryl groups can be monocyclic or polycyclic, i.e. , they can contain one ring (such as, for example, phenyl) or two or more rings, which may also be fused (such as, for example, naphthyl) or covalently bonded (such as, for example, biphenyl), or contain a combination of fused and linked rings.
  • Heteroaryl groups contain one or more heteroatoms, preferably selected from O, N, S and Se.
  • aryl groups having 6 to 25 C atoms and mono-, bi- or tricyclic heteroaryl groups having 5 to 25 ring atoms, which optionally contain fused rings and are optionally substituted.
  • Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl, [1 ,1':3',1"]terphenyl-2'-yl, naphthyl, anthracene, binaphthyl, phenanthrene, 9,10- dihydro-phenanthrene, pyrene, dihydropyrene, chrysene, perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene, etc.
  • 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 rings, such as pyridine, pyridazine, pyrimidine, pyrazine, 1 ,3,5-triazine, 1 ,2,4-triazine, 1 ,2,3-triazine, 1,
  • aryl and heteroaryl groups mentioned above and below may also be substituted by alkyl, alkoxy, thioalkyl, fluorine, fluoroalkyl or further aryl or heteroaryl groups.
  • the (non-aromatic) alicyclic and heterocyclic groups encompass both saturated rings, i.e. , those containing exclusively single bonds, and also partially unsaturated rings, i.e., those which may also contain multiple bonds.
  • Heterocyclic rings contain one or more heteroatoms, preferably selected from Si, O, N, S and Se.
  • the (non-aromatic) alicyclic and heterocyclic groups can be monocyclic, i.e., contain only one ring (such as, for example, cyclohexane), or polycyclic, i.e., contain a plurality of rings (such as, for example, decahydronaphthalene or bicyclooctane). Particular preference is given to saturated groups. Preference is furthermore given to mono-, bi- or tricyclic groups having 5 to 25 ring atoms, which optionally contain fused rings and are optionally substituted.
  • Preferred alicyclic and heterocyclic groups are, for example, 5-membered groups, such as cyclopentane, tetrahydrofuran, tetrahydrothiophen, pyrrolidine, 6-membered groups, such as cyclohexane, silinane, cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1,3-dioxane, 1 ,3-dithiane, piperidine, 7-membered groups, such as cycloheptane, and fused groups, such as tetrahydronaphthalene, 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-methano
  • Preferred substituents are, for example, solubility-promoting groups, such as alkyl or alkoxy, e I ectron-wi th drawing groups, such as fluorine, nitro or nitrile, or substituents for increasing the glass transition temperature (Tg) in the polymer, in particular bulky groups, such as, for example, t-butyl or optionally substituted aryl groups.
  • solubility-promoting groups such as alkyl or alkoxy
  • e I ectron-wi th drawing groups such as fluorine, nitro or nitrile
  • substituents for increasing the glass transition temperature (Tg) in the polymer in particular bulky groups, such as, for example, t-butyl or optionally substituted aryl groups.
  • Y 1 denotes halogen
  • Substituted silyl or aryl preferably means substituted by halogen, -CN, R°, -OR 0 , -CO-R 0 , -CO-O-R 0 , -O-CO-R 0 or -O-CO-O-R 0 , wherein R° denotes H or alkyl with 1 to 20 C atoms.
  • substituents L are, for example, F, Cl, CN, NO 2 , CH3, C 2 Hs, OCH3, OC 2 H 5 , COCH3, COC 2 H 5 , COOCH3, COOC 2 H 5 , CF 3 , OCF3, OCHF 2 , OC 2 F 5 , furthermore phenyl.
  • a 1 and A 2 very preferably denote in which L has one of the meanings indicated above and r denotes 0, 1 , 2, 3 or 4, in particular
  • the polymerisable group P is a group which is suitable for a polymerisation reaction, such as, for example, free-radical or ionic chain polymerisation, polyaddition or polycondensation, or for a polymer-analogous reaction, for example addition or condensation onto a main polymer chain.
  • a polymerisation reaction such as, for example, free-radical or ionic chain polymerisation, polyaddition or polycondensation, or for a polymer-analogous reaction, for example addition or condensation onto a main polymer chain.
  • groups which are suitable for polymerisation with ring opening such as, for example, oxetane or epoxide groups.
  • Preferred groups P are selected from the group consisting of
  • CH 2 CW 2 -(O)k3-
  • CW 1 CH-C0-(0)k3-
  • CW 1 CH-CO-NH-
  • Very preferred groups P are selected from the group consisting of
  • Further preferred polymerisable groups P are selected from the group consisting of vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide, most preferably from acrylate and methacrylate.
  • the spacer group Sp is different from a single bond, it is preferably of the formula Sp"-X", so that the respective radical P-Sp- conforms to the formula R-Sp"-X"-, wherein
  • Sp denotes linear or branched alkylene having 1 to 20, preferably 1 to 12, C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN and in which, in addition, one or more non-adjacent CH 2 groups may each be replaced, independently of one another, by -O-, -S-,
  • R° and R°° each, independently of one another, denote H or alkyl having 1 to 20 C atoms
  • Y 2 and Y 3 each, independently of one another, denote H, F, Cl or CN.
  • X" is preferably -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR 0 -, -NR°-CO-, -NR°-CO-NR 00 - or a single bond.
  • Typical spacer groups Sp and -Sp"-X"- are, for example, -(CH2) P I-, -(CH2) P I-O-, - (CH 2 ) P I-O-CO-, -(CH 2 ) P I-CO-O-, -(CH 2 ) P I-O-CO-O-, -(CH2CH 2 O) q i-CH 2 CH2-, - CH2CH2-S-CH2CH2-, -CH2CH2-NH-CH2CH2- or -(SiR°R 00 -O) p i-, in which p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R° and R°° have the meanings indicated above.
  • Sp and -Sp"-X"- are -(CH2) P I-, -(CH2) P I-O-, -(CH2) P I-O- CO-, -(CH2) P I-CO-O-, -(CH2) P I-O-CO-O-, in which p1 and q1 have the meanings indicated above.
  • Particularly preferred groups Sp" are, in each case straight-chain, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene, ethenylene, propenylene and butenylene.
  • the compounds of formula P and its sub- formulae contain a spacer group Sp that is substituted by one or more polymerisable groups P, so that the group Sp-P corresponds to Sp(P) s , with s being >2 (branched polymerisable groups).
  • Preferred compounds of formula P according to this preferred embodiment are those wherein s is 2, i.e. , compounds which contain a group Sp(P)2.
  • Very preferred compounds of formula P according to this preferred embodiment contain a group selected from the following formulae:
  • X has one of the meanings indicated for X", and is preferably O, CO, SO2, O-CO-, CO-O or a single bond.
  • Preferred spacer groups Sp(P)2 are selected from formulae S1 , S2 and S3.
  • Very preferred spacer groups Sp(P)2 are selected from the following sub-formulae:
  • P is preferably selected from the group consisting of vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide, most preferably from acrylate and methacrylate.
  • R preferably denotes P-Sp-.
  • P-Sp- Further preferred are compounds of formula P and its sub-formulae as described above and below, wherein Sp denotes a single bond or -(CH2) P i-, -O-(CH2) P I-, -O- CO-(CH2) P I , or -CO-O-(CH2) P I , wherein p1 is 2, 3, 4, 5 or 6, and, if Sp is -O-(CH2) P I-, -O-CO-(CH2) P I or -CO-O-(CH2) P I the O-atom or CO-group, respectively, is linked to the benzene ring.
  • At least one group Sp is different from a single bond, and is preferably selected from -(CH 2 ) P I-, -O-(CH 2 ) P I-, -O-CO-(CH 2 ) P I , or -CO-O-(CH 2 ) P I , wherein p1 is 2, 3, 4, 5 or 6, and, if Sp is -O-(CH 2 ) P I-, -O-CO-(CH 2 ) P I or -CO-O- (CH 2 ) P I the O-atom or CO-group, respectively, is linked to the benzene ring.
  • Very preferred groups -A 1 -(Z-A 2 ) z - in formula P are selected from the following formulae
  • At least one benzene ring is substituted by at last one group L and the benzene rings are optionally further substituted by one or more groups L or P-Sp-.
  • Preferred compounds of formula P and their sub-formulae are selected from the following preferred embodiments, including any combination thereof:
  • the compounds contain exactly two polymerizable groups (represented by the groups P),
  • the compounds contain exactly three polymerizable groups (represented by the groups P),
  • - P is selected from the group consisting of acrylate, methacrylate and oxetane, very preferably acrylate or methacrylate,
  • - Sp when being different from a single bond, is -(CH 2 ) p2 -, -(CH 2 ) p2 -O-,
  • - Sp is a single bond or denotes -(CH2) P 2-, -(CH2) P 2-O-, -(CH2) P 2-CO-O-, -(CH2) P 2-O- CO-, wherein p2 is 2, 3, 4, 5 or 6, and the O-atom or the CO-group, respectively, is connected to the benzene ring,
  • - R does not denote or contain a polymerizable group
  • - R does not denote or contain a polymerizable group and denotes straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH2-groups are optionally replaced by -O-,
  • Suitable and preferred compounds of formula P are selected from the following formulae:
  • P 1 , P 2 and P 3 each, independently of one another, denote an acrylate or methacrylate group
  • Sp 1 , Sp 2 and Sp 3 each, independently of one another, denote a single bond or a spacer group having one of the meanings indicated above and below for Sp, and particularly preferably denote -(CH2) P I-, -(CH2) P I-O-, -(CH2) P I-CO-O-, -(CH2) P I-O-CO- or -(CH2) P I-O-CO-O-, in which p1 is an integer from 1 to 12, where, in addition, one or more of the radicals P 1 -Sp 1 -, P 2 -Sp 2 - and P 3 -Sp 3 - may denote R aa , with the proviso that at least one of the radicals P 1 -Sp 1 -, P 2 - Sp 2 - and P 3 -Sp 3 - present is different from R aa ,
  • R°, R°° each, independently of one another and identically or differently on each occurrence denote H or alkyl having 1 to 12 C atoms,
  • R y and R z each, independently of one another, denote H, F, CH 3 or CF 3 , X 1 , X 2 and X 3 each, independently of one another, denote -CO-O-, -O-CO- or a single bond,
  • Z 1 denotes -O-, -CO-, -C(R y R z )- or -CF 2 CF 2 -,
  • Z 2 and Z 3 each, independently of one another, denote -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 on each occurrence denotes F, Cl, CN or straight- chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms, preferably F,
  • L' and L" each, independently of one another, denote H, F or Cl, k denotes 0 or 1 , r denotes 0, 1 , 2, 3 or 4, s denotes 0, 1 , 2 or 3, t denotes 0, 1 or 2, x denotes 0 or 1 .
  • trirezine compounds P15 to P30 in particular P17, P18, P19, P22, P23, P24, P25, P26, P30, P31 and P32.
  • the group wherein L on each occurrence, identically or differently, has one of the meanings given above or below, and is preferably F, Cl, CN, NO 2 , CH3, C 2 Hs, C(CH3)s, CH(CH 3 ) 2 , CH 2 CH(CH 3 )C 2 H 5 , OCH3, OC 2 H 5 , COCH3, COC 2 H 5 , COOCH3, COOC 2 H 5 , CF 3 , OCF 3 , OCHF2, OC2F5 or P-Sp-, very preferably F, Cl, CN, CH 3 , C 2 H 5 , OCH 3 , COCH 3 , OCF 3 or P-Sp-, more preferably F, Cl, CH 3 , OCH 3 , COCH 3 Oder OCF 3 , especially F or CH 3 .
  • Very particularly preferred compounds of the formula P are selected from Table E below, especially selected from the group consisting of formulae RM-1 , RM-4, RM-8, RM-17, RM-19, RM-35, RM-37, RM-39, RM-40, RM-41 , RM-48, RM-52, RM-54, RM-57, RM-58, RM-64, RM-74, RM-76, RM-88, RM-91 , RM-102, RM-103, RM-109, RM-116, RM-117, RM-120, RM-121 , RM-122, RM-139, RM-140, RM-142, RM-143, RM-145, RM-146, RM-147, RM-149, RM-156 to RM-163, RM-169, RM-170 and RM- 171 to RM-183.
  • the polymerisable compounds contained in the LC medium are polymerised or crosslinked (if one compound contains two or more polymerisable groups) by in-situ polymerisation in the LC medium between the substrates of the LC display, optionally while a voltage is applied to the electrodes.
  • the structure of the PSA displays according to the invention corresponds to the usual geometry for PSA displays, as described in the prior art cited at the outset. Geometries without protrusions are preferred, in particular those in which, in addition, the electrode on the colour filter side is unstructured and only the electrode on the TFT side has slots. Particularly suitable and preferred electrode structures for PS-VA displays are described, for example, in US 2006/0066793 A1.
  • a preferred PSA type LC display of the present invention comprises: a first substrate including a pixel electrode defining pixel areas, the pixel electrode being connected to a switching element disposed in each pixel area and optionally including a micro-slit pattern, and optionally a first alignment layer disposed on the pixel electrode, a second substrate including a common electrode layer, which may be disposed on the entire portion of the second substrate facing the first substrate, and optionally a second alignment layer, an LC layer disposed between the first and second substrates and including an LC medium comprising a polymerisable component comprising one or more compounds of formula R and a liquid crystal host including as described above and below, wherein the polymerisable component may also be polymerised.
  • the first and/or second alignment layer controls the alignment direction of the LC molecules of the LC layer.
  • the alignment layer is selected such that it imparts to the LC molecules homeotropic (or vertical) alignment (i.e. , perpendicular to the surface) or tilted alignment.
  • Such an alignment layer may for example comprise a polyimide, which may also be rubbed, or may be prepared by a photoalignment method.
  • the LC layer with the LC medium can be deposited between the substrates of the display by methods that are conventionally used by display manufacturers, for example the so-called one-drop-filling (ODF) method.
  • ODF one-drop-filling
  • the polymerisable component of the LC medium is then polymerised for example by UV photopolymerisation.
  • the polymerisation can be carried out in one step or in two or more steps.
  • the PSA display may comprise further elements, like a colour filter, a black matrix, a passivation layer, optical retardation layers, transistor elements for addressing the individual pixels, etc., all of which are well known to the person skilled in the art and can be employed without inventive skill.
  • the electrode structure can be designed by the skilled person depending on the individual display type. For example, for PS-VA displays a multi-domain orientation of the LC molecules can be induced by providing electrodes having slits and/or bumps or protrusions in order to create two, four or more different tilt alignment directions.
  • the polymerisable compounds Upon polymerisation the polymerisable compounds form a crosslinked polymer, which causes a certain pretilt of the LC molecules in the LC medium. Without wishing to be bound to a specific theory, it is believed that at least a part of the crosslinked polymer, which is formed by the polymerisable compounds, will phase- separate or precipitate from the LC medium and form a polymer layer on the substrates or electrodes, or the alignment layer provided thereon. Microscopic measurement data (like SEM and AFM) have confirmed that at least a part of the formed polymer accumulates at the LC/substrate interface.
  • the polymerisation can be carried out in one step.
  • Suitable and preferred polymerisation methods are, for example, thermal or photopolymerisation, preferably photopolymerisation, in particular UV induced photopolymerisation, which can be achieved by exposure of the polymerisable compounds to UV radiation.
  • one or more polymerisation initiators are added to the LC medium.
  • Suitable conditions for the polymerisation and suitable types and amounts of initiators are known to the person skilled in the art and are described in the literature.
  • Suitable for free-radical polymerisation are, for example, the commercially available photoinitiators Irgacure651®, Irgacure184®, lrgacure907®, Irgacure369® or Darocurel 173® (Ciba AG).
  • a polymerisation initiator is employed, its proportion is preferably 0.001 to 5% by weight, particularly preferably 0.001 to 1% by weight.
  • the polymerisable compounds according to the invention are also suitable for polymerisation without an initiator, which is accompanied by considerable advantages, such, for example, lower material costs and in particular less contamination of the LC medium by possible residual amounts of the initiator or degradation products thereof.
  • the polymerisation can thus also be carried out without the addition of an initiator.
  • the LC medium thus does not contain a polymerisation initiator.
  • the LC medium may also comprise one or more stabilisers in order to prevent undesired spontaneous polymerisation of the RMs, for example during storage or transport.
  • Suitable types and amounts of stabilisers are known to the person skilled in the art and are described in the literature. Particularly suitable are, for example, the commercially available stabilisers from the Irganox® series (Ciba AG), such as, for example, Irganox® 1076. If stabilisers are employed, their proportion, based on the total amount of RMs or the polymerisable component (component P), is preferably 10-500,000 ppm, particularly preferably 50-50,000 ppm.
  • the polymerisable compounds of formula P in particular show good UV absorption in, and are therefore especially suitable for, a process of preparing a PSA display including one or more of the following features:
  • UV-1 step a first UV exposure step
  • UV-2 step a second UV exposure step
  • UV lamps also known as “green UV lamps”.
  • These lamps are characterized by a relative low intensity (1/100-1/10 of a conventional UV1 lamp) in their absorption spectra from 300-380nm, and are preferably used in the UV2 step, but are optionally also used in the UV1 step when avoiding high intensity is necessary for the process.
  • the polymerisable medium is exposed to UV light in the display generated by a UV lamp with a radiation spectrum that is shifted to longer wavelengths, preferably 340nm or more, to avoid short UV light exposure in the PS-VA process.
  • a preferred embodiment of the present invention relates to a process for preparing a PSA display as described above and below, comprising one or more of the following features:
  • UV-1 step a first UV exposure step
  • UV-2 step a second UV exposure step
  • the polymerisable LC medium is exposed to UV light generated by a UV lamp having an intensity of from 0.5 mW/cm 2 to 10 mW/cm 2 in the wavelength range from 300-380nm, preferably used in the UV2 step, and optionally also in the UV1 step,
  • the polymerisable LC medium is exposed to UV light having a wavelength of 340 nm or more, and preferably 400 nm or less.
  • This preferred process can be carried out for example by using the desired UV lamps or by using a band pass filter and/or a cut-off filter, which are substantially transmissive for UV light with the respective desired wavelength(s) and are substantially blocking light with the respective undesired wavelengths.
  • a band pass filter and/or a cut-off filter which are substantially transmissive for UV light with the respective desired wavelength(s) and are substantially blocking light with the respective undesired wavelengths.
  • UV exposure can be carried out using a wide band pass filter being substantially transmissive for wavelengths 300nm ⁇ A ⁇ 400nm.
  • UV exposure can be carried out using a cut-off filter being substantially transmissive for wavelengths A > 340 nm.
  • “Substantially transmissive” means that the filter transmits a substantial part, preferably at least 50% of the intensity, of incident light of the desired wavelength(s). “Substantially blocking” means that the filter does not transmit a substantial part, preferably at least 50% of the intensity, of incident light of the undesired wavelengths.
  • “Desired (undesired) wavelength” e.g., in case of a band pass filter means the wavelengths inside (outside) the given range of A, and in case of a cut-off filter means the wavelengths above (below) the given value of A.
  • This preferred process enables the manufacture of displays by using longer UV wavelengths, thereby reducing or even avoiding the hazardous and damaging effects of short UV light components.
  • UV radiation energy is in general from 6 to 100 J, depending on the production process conditions.
  • the LC medium according to the present invention essentially consist of a polymerisable component P) comprising or one or more polymerisable compounds of formula P, and an LC host mixture, and an optically active component comprising one or more chiral dopants, as described above and below.
  • the LC medium may additionally comprise one or more further components or additives, preferably selected from the list including but not limited to co-monomers, polymerisation initiators, inhibitors, stabilizers, surfactants, wetting agents, lubricating agents, dispersing agents, hydrophobing agents, adhesive agents, flow improvers, defoaming agents, deaerators, diluents, reactive diluents, auxiliaries, colourants, dyes, pigments and nanoparticles.
  • further components or additives preferably selected from the list including but not limited to co-monomers, polymerisation initiators, inhibitors, stabilizers, surfactants, wetting agents, lubricating agents, dispersing agents, hydrophobing agents, adhesive agents, flow improvers, defoaming agents, deaerators, diluents, reactive diluents, auxiliaries, colourants, dyes, pigments and nanoparticles.
  • LC media comprising one, two or three polymerisable compounds of formula P.
  • the proportion of compounds of formula P in the LC medium is from >0 to ⁇ 5%, very preferably from >0 to ⁇ 1%, most preferably from 0.01 to 0.5%.
  • the medium according to the invention preferably comprises one or more compounds of formula S in a total concentration in the range of from 10 ppm to 2000 ppm, more preferably from 100 ppm to 1000 ppm, still more preferably from 150 ppm to 500 ppm, very preferably from 200 ppm to 400 ppm and in particular from 250 to 300 ppm.
  • the medium according to the invention preferably comprises one or more compounds of formula S in a total concentration in the range of from 1000 ppm to 5000 ppm, more preferably from more than 1000 ppm to 5000 ppm, still more preferably from 1200 ppm to 4500 ppm, very preferably from 2000 ppm to 4000 ppm and in particular from 2500 to 3500 ppm.
  • the medium according to the invention preferably has negative dielectric anisotropy.
  • the medium according to the invention comprises one or more compounds of the formula I preferably in a total concentration in the range of from > 0% to 20%, preferably from 1% to 15%, more preferably from 2% to 13%, very preferably from 3% to 12%.
  • the medium according to the invention preferably comprises
  • 11 A, 11 B, IIC and HD or of the formulae 11 B, IIC and HD in a total concentration in the range of from 9% to 70%, more preferably from 10% to 65% and very preferably from 1 % to 64%, in particular from 34% to 42%; and/or
  • one or more compounds of the formula I IB preferably of the formula I IB-2 and/or IIB-10, more preferably of the formula I IB-2 and IIB-10, in a total concentration in the range of from 10% to 50%, more preferably from 15% to 45%, still more preferably from 20% to 40%, in particular from 25% to 35%; and/or
  • one or more compounds of the formula IIC preferably in a total concentration in the range of from 0% to 10%, more preferably from 0.5% to 8% and very preferably from 1 % to 6%, in particular from 1% to 4%; and/or
  • - one or more compounds of the formula III preferably of the formula HI-2, more preferably of the formula HI-2-6, preferably in a total concentration in the range of from 3% to 20%, more preferably from 5% to 17% and very preferably from 6% to 15%; and/or - one or more compounds of the formula HI-2, more preferably of the formula III-2-6, and one or more compounds of the formula HI-3, in a total concentration in the range of from 10% to 30%, more preferably from 15% to 27% and very preferably from 18% to 24%; and/or
  • one or more compounds of the formulae II B and II D and HI preferably in in a total concentration in the range of from 30% to 60%, more preferably from 40% to 53% and very preferably from 43% to 50%; and/or
  • one or more compounds of the formula IV more preferably of the formula IV-3, in a total concentration in the range of from 20% to 65%, more preferably from 25% to 58%, still more preferably from 28% to 55% and very preferably from 30% to 50%, in particular from 33% to 45%; and/or
  • one or more compounds of the formula IV-1 preferably in a total concentration in the range of from 1% to 15%, more preferably from 2% to 12%, still more preferably from 3% to 10% and very preferably from 3% to 8%; and/or
  • one or more compounds of the formula I V-2 preferably in a total concentration in the range of from 0.2% to 5%, more preferably from 0.5% to 3%, still more preferably from 1% to 2%;
  • liquid-crystalline medium preferably of the formula V-6, in a total concentration in the range of from 0.1% to 15%, more preferably from 0.2% to 10%, still more preferably from 0.5% to 5% and very preferably from 1% to 2%; and/or one or more compounds of the formula IIA-Y, preferably of the formula IIA-Y6, in a total concentration in the range of from 0.5% to 10%, more preferably from 1% to 8%, and very preferably from 2% to 5%; and/or one or more compounds of the formula CL-3, preferably selected form the compounds CLP-V-m, CLP-V-Om, CLP-n-m, and CLP-n-Om, in which n and m independently are 1, 2, 34 or 5, preferably in a total concentration in the range of from 1% to 12%, more preferably from 2% to 10% and very preferably from 3% to 7%. It is advantageous for the liquid-crystalline medium according to the invention to preferably have a nematic phase from ⁇
  • ⁇ -30°C to > 72°C very particularly preferably from ⁇ -40°C to > 74°C.
  • the medium according to the invention has a clearing temperature of 70°C or more, preferably of 72°C or more, more preferably of 73°C or more and in particular of 74°C or more.
  • the expression "have a nematic phase” herein means on the one hand that no smectic phase and no crystallisation are observed at low temperatures at the corresponding temperature and on the other hand that clearing (phase transition to the isotropic phase) still does not occur on heating from the nematic phase.
  • the investigation at low temperatures is carried out in a flow viscometer at the corresponding temperature and checked by storage in test cells having a layer thickness corresponding to the electro-optical use for at least 100 hours. If the stor- age stability at a temperature of -20°C in a corresponding test cell is 1000 h or more, the medium is referred to as stable at this temperature. At temperatures of -30°C and -40°C, the corresponding times are 500 h and 250 h respectively. At high temperatures, the clearing point is measured by conventional methods in capillaries.
  • the liquid-crystal mixture preferably has a flow viscosity v 2 o of at most 30 mm 2 • s -1 at 20°C.
  • the liquid crystal mixture according to the invention is nematic, preferably at a temperature of -20°C or less, preferably at -30°C or less, very preferably at -40°C or less.
  • the medium has a birefringence in the range of from 0.100 to 0.155, more preferably from 0.120 to 0.150, very preferably from 0.125 to 0.145 and in particular from 0.128 to 0.138.
  • the liquid-crystal mixture according to the invention has a dielectric anisotropy As of -2.5 to -6.0, preferably of -3.5 to -5.0 , in particular -3.8 to -4.5.
  • the rotational viscosity yi at 20°C is preferably in the range of from 60 to 120 mPas, more preferably from 80 to 110 mPa s.
  • the elastic constant Ki is preferably in the range of from 12.0 to 17.0., more preferably from 13.0 to 16.0, in particular from 14.0 to 15.5.
  • the elastic constant K 3 is preferably in the range of from 12.0 to 16.0., more preferably from 13.0 to 15.0, in particular from 13.5 to 14.5.
  • liquid-crystal media according to the invention have high values for the voltage holding ratio in liquid-crystal cells.
  • liquid-crystal media having a low addressing voltage or threshold voltage exhibit a lower voltage holding ratio than those having a higher addressing voltage or threshold voltage and vice versa.
  • dielectrically positive compounds denotes compounds having a As > 1.5
  • dielectrically neutral compounds denotes those having -1.5 ⁇ As ⁇ 1.5
  • dielectrically negative compounds denotes those having As ⁇ -1.5.
  • the dielectric anisotropy of the compounds is determined here by dissolving 10 % of the compounds in a liquid-crystalline host and determining the capacitance of the resultant mixture in at least one test cell in each case having a layer thickness of 20 pm with homeotropic and with homogeneous surface alignment at 1 kHz.
  • the measurement voltage is typically 0.5 V to 1.0 V but is always lower than the capacitive threshold of the respective liquid- crystal mixture investigated.
  • the mixtures according to the invention are suitable for all VA-TFT applications, such as, for example, VAN, MVA, (S)-PVA, ASV, PSA (polymer sustained VA) and PS-VA (polymer stabilized VA). They are furthermore suitable for IPS (in- ⁇ lane switching) and FFS (fringe field switching) applications having negative As, in particular LIB-FFS.
  • VA, IPS or FFS mixture according to the invention may also comprise compounds in which, for example, H, N, O, Cl and F have been replaced by the corresponding isotopes.
  • the compounds according to the present invention can be synthesized by or in analogy to known methods described in the literature (for example in the standard works such as Houben-Weyl, Methoden der Organischen Chemie [Methods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart), under reaction conditions which are known and suitable for said reactions. Use may also be made here of variants which are known per se but are not mentioned here. In particular, they can be prepared as described in or in analogy to the following reaction schemes. Further methods for preparing the inventive compounds can be taken from the examples.
  • Table A shows the codes for the ring elements of the nuclei of the compound
  • Table B lists the bridging units
  • Table C lists the meanings of the symbols for the left- and right-hand end groups of the molecules.
  • the acronyms are composed of the codes for the ring elements with optional linking groups, followed by a first hyphen and the codes for the left-hand end group, and a second hyphen and the codes for the right- hand end group.
  • Table D shows illustrative structures of compounds together with their respective abbreviations.
  • the mixtures according to the invention optionally comprise one or more compounds of the compounds mentioned below.
  • n, m, k and I are, independently of one another, each an integer, preferably 1 to 9 preferably 1 to 7, k and I possibly may be also 0 and preferably are 0 to 4, more preferably 0 or 2 and most preferably 2, n preferably is 1 , 2, 3, 4 or 5, in the combination “-nO-” it preferably is 1 , 2, 3 or 4, preferably 2 or 4, m preferably is 1 , 2,
  • the combination “-IVm” preferably is “2V1”.
  • Table E shows illustrative reactive mesogenic compounds which can be used in the LC media in accordance with the present invention.
  • the mixtures according to the invention comprise one or more polymerizable compounds, preferably selected from the polymerizable compounds of the formulae RM-1 to RM-182.
  • compounds RM-1, RM-4, RM-8, RM-17, RM-19, RM-35, RM-37, RM-39, RM-40, RM-41, RM-48, RM-52, RM- 54, RM-57, RM-58, RM-64, RM-74, RM-76, RM-88, RM-91, RM-102, RM-103, RM- 109, RM-116, RM-117, RM-120, RM-121, RM-122, RM-139, RM-140, RM-142, RM- 143, RM-145, RM-146, RM-147, RM-149, RM-156 to RM-163, RM-169, RM-170 and RM-171 to RM-183 are particularly
  • threshold voltage for the present invention relates to the capacitive threshold (Vo), also known as the Freedericks threshold, unless explicitly indicated otherwise.
  • the optical threshold may also, as generally usual, be quoted for 10% relative contrast (Vw).
  • the process of polymerising the polymerisable compounds in the PSA displays as described above and below is carried out at a temperature where the LC medium exhibits a liquid crystal phase, preferably a nematic phase, and most preferably is carried out at room temperature.
  • the display used for measurement of the capacitive threshold voltage consists of two plane-parallel glass outer plates with a distance of 25 ⁇ m, each of which has on the inside an electrode layer and an unrubbed polyimide alignment layer on top, which effect homeotropic alignment of the liquid-crystal molecules.
  • the display or test cell used for measurement of the tilt angles consists of two plane-parallel glass outer plates at a separation of 4 ⁇ m, each of which has on the inside an electrode layer and a polyimide alignment layer on top, where the two polyimide layers are rubbed antiparallel to one another and effect a homeotropic edge alignment of the liquid-crystal molecules.
  • the polymerisable compounds are polymerised in the display or test cell by irradiation with UV light of defined intensity for a prespecified time, with a voltage simultaneously being applied to the display (usually 10 V to 30 V alternating current, 1 kHz).
  • a fluorescent lamp and an intensity of 0 to 20 mW/cm 2 is used for polymerisation. The intensity is measured using a standard meter (llshio Accumulate UV meter with central wavelength of 313nm).
  • the transmission measurements are performed in test cells with fishbone electrode layout (from Merck Ltd., Japan; 1 pixel fishbone electrode (ITO, 10x10 mm, 47.7° angle of fishbone with 3pm line/3pm space), 3.2 pm cell gap, AF-glass, tilt angle 1 °).
  • fishbone electrode layout from Merck Ltd., Japan; 1 pixel fishbone electrode (ITO, 10x10 mm, 47.7° angle of fishbone with 3pm line/3pm space), 3.2 pm cell gap, AF-glass, tilt angle 1 °).
  • the storage stability in the bulk (LTSbuik) of the media according to the invention at a given temperature T is determined by visual inspection.
  • 2 g of the media of interest are filled into a closed glass vessel (bottle) of appropriate size placed in a refrigerator at a predetermined temperature.
  • the bottles are checked at defined time intervals for the occurrence of smectic phases or crystallisation. For every material and at each temperature two bottles are stored. If crystallisation or the appearance of a smectic phase is observed in at least one of the two correspondent bottles the test is terminated and the time of the last inspection before the one at which the occurrence of a higher ordered phase is observed is recorded as the respective storage stability.
  • Mixture Examples M1 to M25 and P1 to P9 have the compositions and physical properties indicated in the following tables: Comparative Example C1 PY-3-O2 15.0 % T (N,I) [°C]: 75.0 CLY-3-O2 5.5 % ⁇ n [589 nm, 20°C]: 0.1304 CPY-2-O2 9.0 % n e [589 nm, 20°C]: 1.6235 CPY-3-O2 9.0 % n o [589 nm, 20°C]: 1.4920 B(S)-2O-O4 3.0 % ⁇ ⁇ [1 kHz, 20°C]: -4.0 B(S)-2O-O5 4.0 % ⁇ ⁇ ⁇ [1 kHz, 20°C]: 3.8 B(S)-2O-O6 3.0 % ⁇ ⁇ [1 kHz, 20°C]: 7.8 PGIY-2-O4 6.0 % ⁇ 1 [
  • Mixture Example M1 differs from Comparative Example C1 in the presence of a compound SPY-4-02.
  • a compound SPY-4-02. By use of the compound of formula I, it is surprisingly found that a favorably lower rotational viscosity (yi) and at the same time a very low ratio yi/Ki can be achieved which improves the response time of a display.
  • the mixture example M18 consists of 99.98% of the Mixture example M1 and 0.02% of a compound of the formula ST-12b-1
  • the mixture example M19 consists of 99.985% of the Mixture example M1 and 0.015% of a compound of the formula S1-1a S-1-1a
  • the mixture example M20 consists of 99.98% of the Mixture example M2 and 0.02% of a compound of the formula S2-1a
  • Mixture Example M24 consists of 99.975 % of the medium of mixture example M1 and 0.025 % of the compound ST-3a-2:
  • Mixture Example M25 consists of 99.980 % of the medium of mixture example M2 and 0.020 % of the compound ST-3b-2:
  • the polymerisable mixtures P1 to P9 are prepared from the nematic mixtures given in Table 1 by adding a reactive mesogen (RM) selected from the group of compounds of the formulae RM-1 , RM-17, RM-35, RM-64 and RM-171 , in the amount given in Table 1 (% RM). 7
  • RM reactive mesogen
  • the polymerisable mixture P10 consists of 99.434% of Mixture Example M1 ,

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  • Liquid Crystal Substances (AREA)

Abstract

La présente invention concerne un matériau à cristaux liquides (LC) tel que défini dans la revendication (1), ayant une anisotropie diélectrique négative et son utilisation à des fins optiques, électro-optiques et électroniques, comme par exemple dans des affichages LC, en particulier des affichages à économie d'énergie basés sur l'effet ECB, IPS ou FFS.
PCT/EP2023/086784 2022-12-23 2023-12-20 Milieu à cristaux liquides WO2024133361A1 (fr)

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Citations (9)

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Publication number Priority date Publication date Assignee Title
EP1170626A2 (fr) 2000-07-07 2002-01-09 Fujitsu Limited Dispositif d'affichage à cristal liquide et son procédé de fabrication
US20040191428A1 (en) 2003-03-26 2004-09-30 Fujitsu Display Technologies Corporation Liquid crystal panel
US6861107B2 (en) 2002-07-06 2005-03-01 Merck Patent Gmbh Liquid-crystalline medium
US20060066793A1 (en) 2004-09-24 2006-03-30 Fujitsu Display Technologies Corporation Liquid crystal display device
US20060103804A1 (en) 2004-11-12 2006-05-18 Sharp Kabushiki Kaisha Liquid crystal display device and method of manufacture of the same
US7169449B2 (en) 2002-04-16 2007-01-30 Sharp Kabushiki Kaisha Liquid crystal display device
US20100252777A1 (en) * 2009-04-06 2010-10-07 Merck Patent Gesellschaft Mit Beschrankter Haftung Liquid-crystalline medium and liquid-crystal display
CN110229679A (zh) * 2018-03-06 2019-09-13 北京八亿时空液晶科技股份有限公司 一种液晶介质的自配向添加剂及其制备方法与应用
WO2022003001A1 (fr) * 2020-07-03 2022-01-06 Merck Patent Gmbh Milieu à cristaux liquides

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Publication number Priority date Publication date Assignee Title
EP1170626A2 (fr) 2000-07-07 2002-01-09 Fujitsu Limited Dispositif d'affichage à cristal liquide et son procédé de fabrication
US7169449B2 (en) 2002-04-16 2007-01-30 Sharp Kabushiki Kaisha Liquid crystal display device
US6861107B2 (en) 2002-07-06 2005-03-01 Merck Patent Gmbh Liquid-crystalline medium
US20040191428A1 (en) 2003-03-26 2004-09-30 Fujitsu Display Technologies Corporation Liquid crystal panel
US20060066793A1 (en) 2004-09-24 2006-03-30 Fujitsu Display Technologies Corporation Liquid crystal display device
US20060103804A1 (en) 2004-11-12 2006-05-18 Sharp Kabushiki Kaisha Liquid crystal display device and method of manufacture of the same
US20100252777A1 (en) * 2009-04-06 2010-10-07 Merck Patent Gesellschaft Mit Beschrankter Haftung Liquid-crystalline medium and liquid-crystal display
EP2239310A1 (fr) 2009-04-06 2010-10-13 Merck Patent GmbH Milieu à base de cristaux liquides et affichage à base de cristaux liquides
CN110229679A (zh) * 2018-03-06 2019-09-13 北京八亿时空液晶科技股份有限公司 一种液晶介质的自配向添加剂及其制备方法与应用
WO2022003001A1 (fr) * 2020-07-03 2022-01-06 Merck Patent Gmbh Milieu à cristaux liquides

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PURE APPL. CHEM., vol. 73, no. 5, 2001, pages 888
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