WO1991016396A1 - Milieux de cristaux liquides - Google Patents

Milieux de cristaux liquides Download PDF

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Publication number
WO1991016396A1
WO1991016396A1 PCT/EP1991/000687 EP9100687W WO9116396A1 WO 1991016396 A1 WO1991016396 A1 WO 1991016396A1 EP 9100687 W EP9100687 W EP 9100687W WO 9116396 A1 WO9116396 A1 WO 9116396A1
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WO
WIPO (PCT)
Prior art keywords
compounds
eccp
pch
medium according
formula
Prior art date
Application number
PCT/EP1991/000687
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German (de)
English (en)
Inventor
David Coates
Bernhard Rieger
Reinhard Hittich
Eike Poetsch
Volker Reiffenrath
Herbert Plach
Original Assignee
MERCK Patent Gesellschaft mit beschränkter Haftung
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by MERCK Patent Gesellschaft mit beschränkter Haftung filed Critical MERCK Patent Gesellschaft mit beschränkter Haftung
Publication of WO1991016396A1 publication Critical patent/WO1991016396A1/fr

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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
    • 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
    • C09K19/3028—Cyclohexane rings in which at least two rings are linked by a carbon chain containing carbon to carbon single bonds
    • 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
    • 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
    • C09K19/42—Mixtures of liquid crystal compounds covered by two or more of the preceding groups C09K19/06 - C09K19/40
    • C09K19/44—Mixtures of liquid crystal compounds covered by two or more of the preceding groups C09K19/06 - C09K19/40 containing compounds with benzene rings directly linked

Definitions

  • the present invention relates to a liquid-crystalline medium, its use for electro-optical purposes and displays containing this medium.
  • Liquid crystals are mainly used as dielectrics in display devices, since the optical properties of such substances can be influenced by an applied voltage.
  • Electro-optical devices based on liquid crystals are well known to the person skilled in the art and can be based on various effects. Such devices are, for example, cells with dynamic scattering, DAP cells (deformation of aligned phases), guest / host cells, TN cells with a twisted nematic ("twisted nematic”) structure, STN cells (“super-twisted nematiic”), SBE cells (“super birefringence effect”) and OMI cells (“optical mode interference”).
  • the most common display devices are based on the Schadt-Helfrich effect and have a twisted nematic structure.
  • the liquid crystal materials must have good chemical and thermal stability and good stability against electric fields and electromagnetic radiation. Furthermore, the liquid crystal materials should have a low viscosity and result in short response times, low threshold voltages and a high contrast in the cells. Furthermore, they should have a suitable mesophase at the usual operating temperatures, ie in the widest possible range below and above room temperature, for example a nematic or cholesteric mesophase for the above-mentioned cells. Since liquid crystals are generally used as mixtures of several components, it is important that the components are readily miscible with one another. Other properties, such as the electrical
  • Conductivity, dielectric anisotropy and optical anisotropy have to meet different requirements depending on the cell type and area of application.
  • materials for cells with a twisted nematic structure should have positive dielectric anisotropy and low electrical conductivity.
  • Such matrix liquid crystal displays are known.
  • active elements ie transistors
  • MOS Metal Oxide Semiconductor
  • TFT Thin film transistors
  • the TN effect is usually used as the electro-optical effect.
  • TFTs made of compound semiconductors such as CdSe or TFT's based on polycrystalline or amorphous silicon The latter technology is being worked on with great intensity worldwide.
  • the TFT matrix is applied to the inside of one glass plate of the display, while the other glass plate carries the transparent counter electrode on the inside. Compared to the size of the pixel electrode, the TFT is very small and practically does not disturb the image.
  • This technology can also be expanded for fully color-compatible image representations, a mosaic of red, green and blue filters being arranged in such a way that a filter element is located opposite a switchable image element.
  • the TFT displays work ⁇ ih. ic. usually as TN cells with crossed polarizers in transmission and are illuminated from behind.
  • Such MFK displays are particularly suitable for TV applications (e.g. pocket TVs) or for high-information
  • the object of the invention is to provide media, in particular for such MFK, TN or STN displays, which do not have the disadvantages indicated above or only to a lesser extent, and preferably at the same time have very high resistivities and low threshold voltages.
  • the invention thus relates to a liquid-crystalline medium based on a mixture of polar compounds with positive dielectric anisotropy, characterized in that it contains one or more compounds of the general formula I.
  • L 1 , L 2 and L 3 each H or F, XF, Cl, CF 3 ,
  • the invention also relates to electro-optical displays (in particular STN or MFK displays with two plane-parallel carrier plates which form a cell with a border, integrated non-linear elements for switching individual pixels on the carrier plates and one in the cell located nematic liquid crystal mixture with positive dielectric anisotropy and high resistivity) containing such media and the use of these media for electro-optical purposes.
  • electro-optical displays in particular STN or MFK displays with two plane-parallel carrier plates which form a cell with a border, integrated non-linear elements for switching individual pixels on the carrier plates and one in the cell located nematic liquid crystal mixture with positive dielectric anisotropy and high resistivity
  • liquid crystal mixtures according to the invention allow a significant expansion of the available parameter space.
  • the liquid crystal mixtures according to the invention simultaneously enable dielectric anisotropy values ⁇ ⁇ 3 , 5, preferably ⁇ 4, 0, clear points above
  • the MFK displays according to the invention preferably operate in the first transmission minimum according to Gooch and Tarry [CH Gooch and HA Tarry, Electron. Lett. 10, 2-4, 1974; CH Gooch and HA Tarry, Appl. Phys., Vol.
  • the viscosity at 20 ° C is preferably 25 mPa.s.
  • the nematic phase range is preferably at least 70 °, in particular at least 80 °. This range preferably extends at least from -30 ° to + 70 °.
  • Capacity holding ratio (Hr) measurements [S.Matsumoto et al., Liquid Crystals 5th, 1320 (1989); K. Niwa et al., Proc. SID Conference, San Francisco, June 1984, p. 304 (1984); G.
  • the UV stability of the mixtures according to the invention is also considerably better. H. they show a significantly smaller decrease in HR under UV exposure.
  • the media according to the invention are also distinguished by extraordinarily high elastic constants with very favorable viscosity values, which results in distinct advantages over media from the prior art, particularly when used in STN displays.
  • the media according to the invention are preferably based on several (preferably two or more) compounds of the formula I, i.e. the proportion of these compounds is> 25%, preferably> 40%.
  • - Medium additionally contains one or more compounds selected from the group consisting of the general
  • R alkyl, oxaalkyl, fluoroalkyl or alkenyl, each with up to 7 carbon atoms
  • Y 2 each independently of one another H or F r: 0 or 1.
  • - Medium additionally contains one or more compounds selected from the group consisting of the general formulas V to VIII:
  • Total mixture is 30 to 70% by weight -
  • the medium contains compounds of the formulas II and III or IV - instep straight-chain alkyl or alkenyl with 2 to 7
  • the medium essentially consists of compounds of the formulas I to IV -
  • the medium contains further compounds, preferably selected from the following group:
  • the weight ratio I: (II + III + IV) is preferably 1: 4 to 1: 1.
  • - Medium essentially consists of compounds selected from the group consisting of the general formulas I to XIV.
  • alkyl encompasses straight-chain and branched alkyl groups having 1-7 carbon atoms, in particular the straight-chain groups methyl, ethyl, propyl, butyl, pentyl, hexyl and heptyl. Groups with 2-5 carbon atoms are generally preferred.
  • alkenyl encompasses straight-chain and branched alkenyl groups having 2-7 carbon atoms, in particular the straight-chain groups.
  • Alkenyl groups in particular are C 2 -C 7 -1E-alkenyl, C 4 -C 7 -3E-alkenyl, C 5 -C 7 -4-alkenyl, C 6 -C 7 -5-alkenyl and C 7 -6-alkenyl, in particular C 2 -C 7 -1E alkenyl, C 4 -C 7 -3E alkenyl and C 5 -C 7 -4 alkenyl.
  • Examples of preferred alkenyl groups are
  • fluoroalkyl preferably encompasses straight-chain groups with terminal fluorine, ie fluoromethyl, 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl, 5-fluoropentyl, 6-fluorohexyl and 7-fluoroheptyl. However, other positions of the fluorine are not excluded.
  • the response times, the threshold voltage, the steepness of the transmission characteristics, etc. can be modified in a desired manner by a suitable choice of the meanings of R, X and Y.
  • 1E-alkenyl residues, 3E-alkenyl residues, 2E-alkenyloxy residues and the like generally lead to shorter response times, improved nematic tendencies and a higher ratio of the elastic constants k 33
  • the total amount of compounds of the formulas I to XII in the mixtures according to the invention is not critical.
  • the mixtures can therefore contain one or more further components in order to optimize various properties.
  • the observed effect on the response times and the threshold voltage is generally greater the higher the total concentration of compounds of the formulas I to XIV.
  • the media according to the invention contain compounds of the formula II, III, V and / or VII (preferably II and / or III), in which X is CF 3 , OCF 3 or OCHF 2 .
  • X is CF 3 , OCF 3 or OCHF 2 .
  • the media preferably contain compounds selected from the group consisting of the formulas V to VIII, where X preferably denotes OCHF 2 .
  • the media according to the invention can also contain a component A consisting of one or more compounds having a dielectric anisotropy of -1.5 to +1.5 of the general formula I ' I '
  • R 1 and R 2 each independently of one another n-alkyl, fluoroalkyl or n-alkenyl having up to 9 carbon atoms, the rings A 1 , A 2 and A 3
  • Z 1 and Z 2 are each independently of one another -CH 2 CH 2 -, C ⁇ C-,
  • n 0, 1 or 2.
  • Component A preferably contains one or more compounds selected from the group consisting of II1 to II7: II1 II2 II3
  • Component A preferably additionally contains one or more compounds selected from the group consisting of II8 to II20: II8 II9 II10 II11 II12 II13 II14 II15
  • R 1 and R 2 have the meaning given for formula I 'and the 1,4-phenylene groups in II8 to II17 each
  • Component A also preferably contains one or more compounds selected from the group consisting of II21 to II25 and contains: II21 II22 II23 II24
  • R 1 and R 2 have the meaning given in formula I 'and the 1,4-phenylene groups in II21 to II25 each
  • C r H 2r + 1 is a straight-chain alkyl group with up to 7
  • R 1 and R 2 have the meaning given for formula I 'and
  • liquid crystal mixtures which contain one or more compounds selected from the group consisting of III 'and IV:
  • Ri and R 2 have the meaning given for formula I '.
  • the type and amount of polar compounds with positive dielectric anisotropy is not critical. The person skilled in the art can select suitable materials in simple routine tests from a wide range of known and in many cases also commercially available components and base mixtures.
  • the media according to the invention preferably contain one or more compounds of the formula I "
  • Z 1 , Z 2 and m have the meaning given for formula I ', Q 1 and Q 2 each independently of one another 1,4-phenylene, trans-1, 4-cyclohexylene or 3-fluoro-1,4-phenylene or one of the radicals Q 1 and Q 2 also means trans-1,3-dioxane-2, 5-diyl, pyrimidine-2, 5-diyl, pyridine-2, 5-diyl or 1,4-cyclohexenylene.
  • the structure of the STN or MFK display according to the invention from polarizers, electrode base plates and electrodes with surface treatment corresponds to the design customary for such displays.
  • the term conventional construction is broadly encompassed here and also includes all modifications and modifications of the MLC display, in particular also matrix display elements based on poly-Si TFT or MIM.
  • the liquid crystal mixtures which can be used according to the invention are prepared in a manner which is conventional per se. As a rule, the desired amount of the components used in smaller amounts is dissolved in the components which make up the main constituent, advantageously at elevated temperature. It is also possible to mix solutions of the components in an organic solvent, for example in acetone, chloroform or methanol, and to remove the solvent after thorough mixing, for example by distillation.
  • the dielectrics can also contain further additives known to the person skilled in the art and described in the literature. For example, 0-15% pleochroic dyes or chiral dopants can be added.
  • C means a crystalline, S a smectic, S B a smectic B, N a nematic and I the isotropic phase.
  • V 10 denotes the voltage for 10% transmission (viewing direction perpendicular to the plate surface).
  • t on denotes the
  • the electro-optical data were measured in a TN cell at the 1st minimum (ie at a d n value of 0.5) at 20 ° C, unless expressly stated otherwise.
  • the optical data were measured at 20 ° C, unless expressly stated otherwise.
  • the following examples are intended to illustrate the invention without limiting it. All temperatures above and below are given in ° C. The percentages are percentages by weight.
  • Table A shows only the acronym for the base body.
  • a code for the substituents R 1 , R 2 , L 1 , L 2 and L 3 follows with a dash, separately from the acronym for the base body:
  • Table A Table B:
  • the above liquid-crystalline media of Examples 1 to 7 are particularly suitable for MLC displays.
  • liquid-crystalline media for STN displays can also be produced.
  • the liquid-crystalline media for STN displays according to the invention generally have a birefringence between 0.12 and 0.17, preferably 0.12 and 0.15, in particular 0.125 and 0.145.
  • the media according to the invention for STN displays contain 0-40%, preferably 5% to 35%, in particular 10% to 30% of a liquid-crystalline component of the formula I 'with a dielectric anisotropy of -1.5 to +1.5, in particular selected from the group I'a to I'n:
  • R 1 and R 2 have the meaning given for formula I ', but preferably alkyl or alkoxy having 1 to 8, in particular 2 to 5, carbon atoms and the 1,4-phenylene groups, independently of one another, also by fluorine can be substituted several times.
  • the liquid crystal mixtures used in the STN displays are dielectrically positive with ⁇ > 1, preferably ⁇ 3, in particular ⁇ 5.
  • the STN mixtures according to the invention are further characterized by advantageous values for the steepness of the electro-optical characteristic curve and can be operated at high multiplex rates.
  • Example A relate to liquid-crystalline media according to the invention for STN cells:
  • This mixture has the following physical properties:
  • a liquid-crystalline medium for an STN cell (twist 240 °) is produced, consisting of: ECCP-3Cl 10.4%
  • This mixture has the following physical properties:
  • a liquid-crystalline medium for an STN cell (twist 240 °) is produced, consisting of: ECCP-3Cl 8.0%
  • This mixture has the following physical properties:
  • a liquid-crystalline medium for an STN cell (twist 240 °) is produced, consisting of:
  • This mixture has the following physical properties:
  • a liquid-crystalline medium for an STN cell (twist 240 °) is produced, consisting of:
  • This mixture has the following physical properties:
  • This mixture has the following properties:
  • This mixture has the following physical properties:
  • This mixture has the following physical properties:
  • This mixture has the following physical properties:
  • This mixture has the following physical properties:
  • This mixture has the following physical properties:
  • This mixture has the following physical properties:
  • a basic mixture (A) consisting of
  • CCPC-35 5% has the following properties:
  • V th 2.31 volts.
  • STN mixtures according to the invention are produced, consisting of 80% base mixture (A) and 20% of a compound of the formula Ia
  • a basic mixture (B) consisting of
  • ME-2N.F 3.0% has the following physical properties:
  • NI 94.9 ° C
  • STN mixtures according to the invention are produced consisting of different amounts of base mixture (B) and a compound of the formula Ia or CEUPnX.L 2

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  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Liquid Crystal Substances (AREA)

Abstract

L'invention concerne un milieu de cristaux liquides à base d'un mélange de composés polaires à anisotropie diélectrique positive, caractérisé en ce qu'il renferme un ou plusieurs composés de formule générale (I) dans laquelle L?1, L2 et L3¿ désignent chacun H ou F, X désigne F, Cl, CF¿3?, OCF3 ou OCHF2, l'un des restes Q?1 et Q2¿ désigne -C¿2?H4- et l'autre reste Q?1 ou Q2¿ est une liaison simple, et R désigne un alkyle, oxa-alkyle, fluoro-alkyle ou alcényle ayant chacun jusqu'à 7 atomes de carbone.
PCT/EP1991/000687 1990-04-13 1991-04-11 Milieux de cristaux liquides WO1991016396A1 (fr)

Applications Claiming Priority (2)

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DE4012036 1990-04-13
DEP4012036.8 1990-04-13

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1993002153A1 (fr) * 1991-07-16 1993-02-04 MERCK Patent Gesellschaft mit beschränkter Haftung Milieu a cristaux liquides
EP0540044A1 (fr) * 1991-11-01 1993-05-05 MERCK PATENT GmbH Composition liquide cristalline nématique
EP0609566A1 (fr) * 1992-12-28 1994-08-10 Chisso Corporation Composition liquide cristalline
US5520846A (en) * 1991-07-16 1996-05-28 Merck Patent Gesellschaft Mit Beschrankter Haftung Liquid-crystalline medium
EP0478738B1 (fr) * 1990-04-13 1996-12-27 MERCK PATENT GmbH Milieu de cristaux liquides
EP0761799A1 (fr) * 1995-09-11 1997-03-12 Chisso Corporation Composé liquide cristalline à substituant groupe fluoré, composition liquide cristalline et dispositif d'affichage
US6013198A (en) * 1995-09-11 2000-01-11 Chisso Corporation Liquid crystalline compound replaced by fluorine containing group, liquid crystal composition, and liquid crystal display device
EP1835010A1 (fr) 2006-03-17 2007-09-19 Merck Patent GmbH Milieu liquide cristallin et dispositif d'affichage à cristaux liquides
US7563491B2 (en) 2006-03-17 2009-07-21 Merck Patent Gmbh Liquid crystalline medium and liquid crystal display

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3233641A1 (de) * 1981-09-10 1983-03-24 Dainippon Ink and Chemicals, Inc., Tokyo Neue nematische halogenverbindungen
WO1985004874A1 (fr) * 1984-04-16 1985-11-07 Merck Patent Gmbh Composes anisotropes et melanges de cristaux liquides avec ceux-ci
EP0205998A1 (fr) * 1985-06-10 1986-12-30 Chisso Corporation Dérivé de cyclohexane et composition de cristaux liquides le contenant
WO1990001056A1 (fr) * 1988-07-27 1990-02-08 MERCK Patent Gesellschaft mit beschränkter Haftung Composes de difluoromethyle
WO1990015115A1 (fr) * 1989-05-30 1990-12-13 MERCK Patent Gesellschaft mit beschränkter Haftung Derives de byphenyles fluorures
DE4027840A1 (de) * 1989-09-06 1991-03-07 Merck Patent Gmbh Fluorbenzolderivate und fluessigkristallines medium
EP0416117A1 (fr) * 1989-02-14 1991-03-13 Chisso Corporation Preparation a base de cristaux liquides

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3233641A1 (de) * 1981-09-10 1983-03-24 Dainippon Ink and Chemicals, Inc., Tokyo Neue nematische halogenverbindungen
WO1985004874A1 (fr) * 1984-04-16 1985-11-07 Merck Patent Gmbh Composes anisotropes et melanges de cristaux liquides avec ceux-ci
EP0205998A1 (fr) * 1985-06-10 1986-12-30 Chisso Corporation Dérivé de cyclohexane et composition de cristaux liquides le contenant
WO1990001056A1 (fr) * 1988-07-27 1990-02-08 MERCK Patent Gesellschaft mit beschränkter Haftung Composes de difluoromethyle
EP0416117A1 (fr) * 1989-02-14 1991-03-13 Chisso Corporation Preparation a base de cristaux liquides
WO1990015115A1 (fr) * 1989-05-30 1990-12-13 MERCK Patent Gesellschaft mit beschränkter Haftung Derives de byphenyles fluorures
DE4027840A1 (de) * 1989-09-06 1991-03-07 Merck Patent Gmbh Fluorbenzolderivate und fluessigkristallines medium

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0478738B1 (fr) * 1990-04-13 1996-12-27 MERCK PATENT GmbH Milieu de cristaux liquides
WO1993002153A1 (fr) * 1991-07-16 1993-02-04 MERCK Patent Gesellschaft mit beschränkter Haftung Milieu a cristaux liquides
US5520846A (en) * 1991-07-16 1996-05-28 Merck Patent Gesellschaft Mit Beschrankter Haftung Liquid-crystalline medium
EP0540044A1 (fr) * 1991-11-01 1993-05-05 MERCK PATENT GmbH Composition liquide cristalline nématique
EP0609566A1 (fr) * 1992-12-28 1994-08-10 Chisso Corporation Composition liquide cristalline
US5439613A (en) * 1992-12-28 1995-08-08 Chisso Corporation Liquid crystal composition
EP0761799A1 (fr) * 1995-09-11 1997-03-12 Chisso Corporation Composé liquide cristalline à substituant groupe fluoré, composition liquide cristalline et dispositif d'affichage
US6013198A (en) * 1995-09-11 2000-01-11 Chisso Corporation Liquid crystalline compound replaced by fluorine containing group, liquid crystal composition, and liquid crystal display device
EP1835010A1 (fr) 2006-03-17 2007-09-19 Merck Patent GmbH Milieu liquide cristallin et dispositif d'affichage à cristaux liquides
US7563491B2 (en) 2006-03-17 2009-07-21 Merck Patent Gmbh Liquid crystalline medium and liquid crystal display
US7740918B2 (en) 2006-03-17 2010-06-22 Merck Patent Gmbh Liquid crystalline medium and liquid crystal display

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