GB2394475A - High-twist liquid-crystalline medium and liquid-crystal display - Google Patents
High-twist liquid-crystalline medium and liquid-crystal display Download PDFInfo
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- GB2394475A GB2394475A GB0320640A GB0320640A GB2394475A GB 2394475 A GB2394475 A GB 2394475A GB 0320640 A GB0320640 A GB 0320640A GB 0320640 A GB0320640 A GB 0320640A GB 2394475 A GB2394475 A GB 2394475A
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- 239000004973 liquid crystal related substance Substances 0.000 title abstract description 5
- 150000001875 compounds Chemical class 0.000 claims abstract description 77
- -1 1,3-dioxolane-4,5-diyl Chemical group 0.000 claims description 106
- 125000004432 carbon atom Chemical group C* 0.000 claims description 49
- 125000000217 alkyl group Chemical group 0.000 claims description 40
- 230000003098 cholesteric effect Effects 0.000 claims description 28
- 229910052731 fluorine Inorganic materials 0.000 claims description 21
- 239000000203 mixture Substances 0.000 claims description 21
- 125000003545 alkoxy group Chemical group 0.000 claims description 19
- 229910052801 chlorine Inorganic materials 0.000 claims description 16
- 125000003342 alkenyl group Chemical group 0.000 claims description 13
- 229910052739 hydrogen Inorganic materials 0.000 claims description 10
- 229910052736 halogen Inorganic materials 0.000 claims description 9
- 125000004430 oxygen atom Chemical group O* 0.000 claims description 9
- 229910052794 bromium Inorganic materials 0.000 claims description 8
- 229910052740 iodine Inorganic materials 0.000 claims description 8
- 229910052760 oxygen Inorganic materials 0.000 claims description 7
- 125000004434 sulfur atom Chemical group 0.000 claims description 7
- 125000003118 aryl group Chemical group 0.000 claims description 6
- 125000001140 1,4-phenylene group Chemical group [H]C1=C([H])C([*:2])=C([H])C([H])=C1[*:1] 0.000 claims description 5
- 150000002367 halogens Chemical class 0.000 claims description 5
- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims description 5
- 229910052757 nitrogen Inorganic materials 0.000 claims description 5
- 125000004955 1,4-cyclohexylene group Chemical group [H]C1([H])C([H])([H])C([H])([*:1])C([H])([H])C([H])([H])C1([H])[*:2] 0.000 claims description 4
- 125000004453 alkoxycarbonyl group Chemical group 0.000 claims description 4
- 125000004448 alkyl carbonyl group Chemical group 0.000 claims description 4
- 125000005843 halogen group Chemical group 0.000 claims description 4
- 125000004093 cyano group Chemical group *C#N 0.000 claims description 3
- 125000000449 nitro group Chemical group [O-][N+](*)=O 0.000 claims description 3
- 125000001931 aliphatic group Chemical group 0.000 claims description 2
- 125000000753 cycloalkyl group Chemical group 0.000 claims description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical group [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims 2
- 125000005725 cyclohexenylene group Chemical group 0.000 claims 1
- 239000004986 Cholesteric liquid crystals (ChLC) Substances 0.000 description 30
- 150000003254 radicals Chemical class 0.000 description 25
- WCLNGBQPTVENHV-MKQVXYPISA-N cholesteryl nonanoate Chemical compound C([C@@H]12)C[C@]3(C)[C@@H]([C@H](C)CCCC(C)C)CC[C@H]3[C@@H]1CC=C1[C@]2(C)CC[C@H](OC(=O)CCCCCCCC)C1 WCLNGBQPTVENHV-MKQVXYPISA-N 0.000 description 16
- 239000002019 doping agent Substances 0.000 description 15
- 239000000463 material Substances 0.000 description 11
- 125000002023 trifluoromethyl group Chemical group FC(F)(F)* 0.000 description 10
- 125000000876 trifluoromethoxy group Chemical group FC(F)(F)O* 0.000 description 9
- 239000011295 pitch Substances 0.000 description 8
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 7
- 125000000956 methoxy group Chemical group [H]C([H])([H])O* 0.000 description 6
- 125000004786 difluoromethoxy group Chemical group [H]C(F)(F)O* 0.000 description 4
- QUPDWYMUPZLYJZ-UHFFFAOYSA-N ethyl Chemical compound C[CH2] QUPDWYMUPZLYJZ-UHFFFAOYSA-N 0.000 description 4
- 125000001153 fluoro group Chemical group F* 0.000 description 4
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 3
- JNCMHMUGTWEVOZ-UHFFFAOYSA-N F[CH]F Chemical compound F[CH]F JNCMHMUGTWEVOZ-UHFFFAOYSA-N 0.000 description 3
- 108010081348 HRT1 protein Hairy Proteins 0.000 description 3
- 102100021881 Hairy/enhancer-of-split related with YRPW motif protein 1 Human genes 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 239000000654 additive Substances 0.000 description 3
- 125000000484 butyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 3
- 125000000816 ethylene group Chemical group [H]C([H])([*:1])C([H])([H])[*:2] 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- 125000004975 3-butenyl group Chemical group C(CC=C)* 0.000 description 2
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- JCXJVPUVTGWSNB-UHFFFAOYSA-N Nitrogen dioxide Chemical compound O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 125000004429 atom Chemical group 0.000 description 2
- 125000001309 chloro group Chemical group Cl* 0.000 description 2
- ZUOUZKKEUPVFJK-UHFFFAOYSA-N diphenyl Chemical group C1=CC=CC=C1C1=CC=CC=C1 ZUOUZKKEUPVFJK-UHFFFAOYSA-N 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- VUWZPRWSIVNGKG-UHFFFAOYSA-N fluoromethane Chemical compound F[CH2] VUWZPRWSIVNGKG-UHFFFAOYSA-N 0.000 description 2
- 125000004785 fluoromethoxy group Chemical group [H]C([H])(F)O* 0.000 description 2
- 125000003187 heptyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 2
- 125000004051 hexyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 2
- IHPDTPWNFBQHEB-UHFFFAOYSA-N hydrobenzoin Chemical compound C=1C=CC=CC=1C(O)C(O)C1=CC=CC=C1 IHPDTPWNFBQHEB-UHFFFAOYSA-N 0.000 description 2
- 125000000959 isobutyl group Chemical group [H]C([H])([H])C([H])(C([H])([H])[H])C([H])([H])* 0.000 description 2
- 125000001972 isopentyl group Chemical group [H]C([H])([H])C([H])(C([H])([H])[H])C([H])([H])C([H])([H])* 0.000 description 2
- 125000001449 isopropyl group Chemical group [H]C([H])([H])C([H])(*)C([H])([H])[H] 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 125000001147 pentyl group Chemical group C(CCCC)* 0.000 description 2
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 2
- 239000004038 photonic crystal Substances 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 125000001436 propyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])[H] 0.000 description 2
- 125000002914 sec-butyl group Chemical group [H]C([H])([H])C([H])([H])C([H])(*)C([H])([H])[H] 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 125000001424 substituent group Chemical group 0.000 description 2
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 2
- 229920002554 vinyl polymer Polymers 0.000 description 2
- 238000001429 visible spectrum Methods 0.000 description 2
- 125000005739 1,1,2,2-tetrafluoroethanediyl group Chemical group FC(F)([*:1])C(F)(F)[*:2] 0.000 description 1
- KOUJXMCSGVVSRF-UHFFFAOYSA-N 1,2-diphenylethane-1,1-diol Chemical compound C=1C=CC=CC=1C(O)(O)CC1=CC=CC=C1 KOUJXMCSGVVSRF-UHFFFAOYSA-N 0.000 description 1
- HNEGJTWNOOWEMH-UHFFFAOYSA-N 1-fluoropropane Chemical group [CH2]CCF HNEGJTWNOOWEMH-UHFFFAOYSA-N 0.000 description 1
- KWKAKUADMBZCLK-UHFFFAOYSA-N 1-octene Chemical group CCCCCCC=C KWKAKUADMBZCLK-UHFFFAOYSA-N 0.000 description 1
- 125000004793 2,2,2-trifluoroethoxy group Chemical group FC(CO*)(F)F 0.000 description 1
- 125000004206 2,2,2-trifluoroethyl group Chemical group [H]C([H])(*)C(F)(F)F 0.000 description 1
- 125000004777 2-fluoroethyl group Chemical group [H]C([H])(F)C([H])([H])* 0.000 description 1
- 125000004200 2-methoxyethyl group Chemical group [H]C([H])([H])OC([H])([H])C([H])([H])* 0.000 description 1
- 125000004493 2-methylbut-1-yl group Chemical group CC(C*)CC 0.000 description 1
- 125000005916 2-methylpentyl group Chemical group 0.000 description 1
- 125000005917 3-methylpentyl group Chemical group 0.000 description 1
- 125000006043 5-hexenyl group Chemical group 0.000 description 1
- 208000016057 CHAND syndrome Diseases 0.000 description 1
- 101100135744 Caenorhabditis elegans pch-2 gene Proteins 0.000 description 1
- SNRUBQQJIBEYMU-UHFFFAOYSA-N Dodecane Natural products CCCCCCCCCCCC SNRUBQQJIBEYMU-UHFFFAOYSA-N 0.000 description 1
- 101100495923 Schizosaccharomyces pombe (strain 972 / ATCC 24843) chr2 gene Proteins 0.000 description 1
- 239000004990 Smectic liquid crystal Substances 0.000 description 1
- OWVIRVJQDVCGQX-VSGBNLITSA-N [(4r,5r)-5-[hydroxy(diphenyl)methyl]-2,2-dimethyl-1,3-dioxolan-4-yl]-diphenylmethanol Chemical class C=1C=CC=CC=1C(O)([C@H]1[C@@H](OC(O1)(C)C)C(O)(C=1C=CC=CC=1)C=1C=CC=CC=1)C1=CC=CC=C1 OWVIRVJQDVCGQX-VSGBNLITSA-N 0.000 description 1
- DHKHKXVYLBGOIT-UHFFFAOYSA-N acetaldehyde Diethyl Acetal Natural products CCOC(C)OCC DHKHKXVYLBGOIT-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 125000002619 bicyclic group Chemical group 0.000 description 1
- 239000004305 biphenyl Chemical group 0.000 description 1
- 235000010290 biphenyl Nutrition 0.000 description 1
- 125000004744 butyloxycarbonyl group Chemical group 0.000 description 1
- 150000001841 cholesterols Chemical class 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 229920001577 copolymer Chemical group 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- WVIIMZNLDWSIRH-UHFFFAOYSA-N cyclohexylcyclohexane Chemical group C1CCCCC1C1CCCCC1 WVIIMZNLDWSIRH-UHFFFAOYSA-N 0.000 description 1
- JHAYEQICABJSTP-UHFFFAOYSA-N decoquinate Chemical group N1C=C(C(=O)OCC)C(=O)C2=C1C=C(OCC)C(OCCCCCCCCCC)=C2 JHAYEQICABJSTP-UHFFFAOYSA-N 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 125000002704 decyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 125000003438 dodecyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000005670 electromagnetic radiation Effects 0.000 description 1
- AZHSSKPUVBVXLK-UHFFFAOYSA-N ethane-1,1-diol Chemical class CC(O)O AZHSSKPUVBVXLK-UHFFFAOYSA-N 0.000 description 1
- 125000003754 ethoxycarbonyl group Chemical group C(=O)(OCC)* 0.000 description 1
- 125000005745 ethoxymethyl group Chemical group [H]C([H])([H])C([H])([H])OC([H])([H])* 0.000 description 1
- 125000003709 fluoroalkyl group Chemical group 0.000 description 1
- 125000004216 fluoromethyl group Chemical group [H]C([H])(F)* 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 125000001160 methoxycarbonyl group Chemical group [H]C([H])([H])OC(*)=O 0.000 description 1
- 125000004184 methoxymethyl group Chemical group [H]C([H])([H])OC([H])([H])* 0.000 description 1
- GRVDJDISBSALJP-UHFFFAOYSA-N methyloxidanyl Chemical compound [O]C GRVDJDISBSALJP-UHFFFAOYSA-N 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 125000001421 myristyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 125000001400 nonyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 125000002347 octyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 239000012788 optical film Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 125000005740 oxycarbonyl group Chemical group [*:1]OC([*:2])=O 0.000 description 1
- 125000002958 pentadecyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 125000001148 pentyloxycarbonyl group Chemical group 0.000 description 1
- 125000004351 phenylcyclohexyl group Chemical group C1(=CC=CC=C1)C1(CCCCC1)* 0.000 description 1
- 125000004742 propyloxycarbonyl group Chemical group 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 125000005407 trans-1,4-cyclohexylene group Chemical group [H]C1([H])C([H])([H])[C@]([H])([*:2])C([H])([H])C([H])([H])[C@@]1([H])[*:1] 0.000 description 1
- 125000002889 tridecyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 125000002948 undecyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Classifications
-
- 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
-
- 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
-
- 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
- C09K19/46—Mixtures of liquid crystal compounds covered by two or more of the preceding groups C09K19/06 - C09K19/40 containing esters
-
- 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
- C09K19/52—Liquid crystal materials characterised by components which are not liquid crystals, e.g. additives with special physical aspect: solvents, solid particles
- C09K19/58—Dopants or charge transfer agents
- C09K19/586—Optically active dopants; chiral dopants
-
- 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
- C09K19/52—Liquid crystal materials characterised by components which are not liquid crystals, e.g. additives with special physical aspect: solvents, solid particles
- C09K19/58—Dopants or charge transfer agents
- C09K19/586—Optically active dopants; chiral dopants
- C09K19/588—Heterocyclic compounds
Landscapes
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Liquid Crystal Substances (AREA)
Abstract
A liquid crystal medium with a helically twisted phase comprising a nematic component and an optically active component wherein the optically active component comprises one or more chiral compounds at least one of which is a chiral derivative of formula I. Also shown is its use for LC displays, SSCT and PCST displays, or for lasing or fluorescence applications.
Description
- 1 High-twist liquid-crystalline medium and liquid-crystal display Field
of the Invention
5 The present invention relates to a high-twist liquid-crystalline (LC) medium, to its use for decorative or security applications, temperature indicators, lasing and fluorescence phenomena and LC displays, and to decorative products, security markings or devices, lasing devices and LC displays containing the LC medium.
Backoround and Prior Art
Cholesteric liquid crystals (CLCs) exhibit selective reflection of circularly polarized light, wherein the direction of rotation of the light 15 vector corresponds to the handedness of the cholesteric helix.
The terms "chiral nematic" LCs and "cholesteric" LCs are used simultaneously in the prior art. "Chiral nematic" often refers to LC
materials consisting of a nematic host mixture doped with an optically 20 active component which induces a helically twisted superstructure, whereas "cholesteric" often refers to chiral LC materials, for example cholesterol derivatives, which have a "natural" helically twisted cholesteric phase. Both terms are also used in parallel to mean the same thing. In the present application, both of the above mentioned 25 types of LC materials are referred to as "cholesteric", and this term is meant to encompass the broadest meaning of both "chiral nematic" and "cholesteric".
In CLC materials the bandwidth of the reflection spectrum An, 30 centered at maX'is given by: AX = \x- (1) n 35 where An is the birefringence and n is the average refractive index, both associated with the director plane (i.e. not in the bulk).
- 2 The wavelength hmaX is defined as hmax = n P (2) 5 where p is the pitch of the cholesteric helix.
Substituting equation (2) into equation (1) leads to: = p An (3) A chiral nematic phase can for example be induced by adding a few percent of chiral additive to a nematic LC host mixture, which is characterized by the extraordinary and ordinary refractive indices ne and nO. In this case, the parameters of equation (1) become An=ne-nOandn=(ne+nO)/2 The helical pitch of the induced cholesteric phase is given by 20 PO = (HTP c) (4) wherein c is the concentration c and HTP the helical twisting power of the chiral additive.
25 CLC materials have been suggested in prior art for a broad variety of
applications, like for example liquid crystal displays (LCD), optical films like polarisers and colour filters, decorative and security uses, diagnostics and temperature indicators.
30 For example, it has been suggested in prior art to use CLCs for
methods and devices utilizing the lasing and fluorescence phenomenon. US 3,771,065 for example describes the principle of lasing in CLCs.
35 CLCs have further been suggested for use in LC displays. For example, cholesteric LCDs like SSCT (surface stabilized cholesteric
- 3 texture) and PSCT (polymer stabilized cholesteric texture) displays are known, which contain CLC media that selectively reflect circular polarized light within or close to the visible wavelength range. SSCT and PSCT displays are described for example in WO 92/19695, US 5 5,384,067 and US 5,453,863.
Furthermore, flexoelectric displays are known using CLC materials having a flexoelectric effect, in particular those operated in the so called uniformly lying helix (ULH) mode. The uniform lying helix 10 (ULH) texture is as described for example by Patel and Meyer, Phys. Rev. Lett. 58 (15),1538-1540 (1987) and Rudquist et al., Liq. Cryst.
22 (4), 445-449 (1997) and Liq. Cryst. 23 (4),503 (1997). CLC materials for use in flexoelectric devices are described e.g. in EP O 971 016 and GB 2 356 629.
CLCs can also be used in decorative and security applications, temperature indicators and diagnostics. Thus, e.g. thermochromic CLC media or devices are known, which show a change of pitch and thus of the reflection colour within the cholesteric phase upon a 20 change of the temperature. Alternatively, so-called monochromic or temperature insensitive CLC media or devices can be used, which exhibit a single reflection up to the chiral to isotropic transition temperature (Tc') from 20 C below it. The thermochromic and monochromic CLCs have been suggested for example for use as 25 temperature indicators, e.g. in product labels, or as authentification, identification or false-proof security labels or markings on products or documents of value. For the above uses, low molar mass CLCs are typically encapsulated in transparent polymer shells to give an ink or slurry, or are confined between transparent substrates.
However, the CLC materials used in prior art have several
drawbacks. For example, in case of CLCs comprising a nematic LC host doped with a chiral aditive, the chiral dopant often has an adverse effect on the liquid-crystalline properties of the LC host.
35 Also, the chiral dopants known in prior art often exhibit low twisting
power, so that high amounts are required to achieve small pitches.
Furthermore, the dopants often have low solubility in the LC host and show crystallization especially at low temperatures.
Therefore, there is a need for improved CLC media which are 5 suitable for the above mentioned uses and which do not have the disadvantages of the media of the prior art, or at least do so to a
significantly reduced extent.
Generally, the CLC media should have a good chemical and thermal 10 stability and a good stability towards electric fields and
electromagnetic radiation. Furthermore, they should have a cholesteric LC phase in the desired temperature range and a sufficiently high birefringence. The CLC should also allow to realize different reflection wavelengths, in particular in the visible range, by 15 simple and controlled variation.
The chiral dopants used in the CLC media should exhibit a high twisting power, a high stability and a good solubility in the LC host.
20 For specific uses as temperature indicators there is a need for CLC media showing a clearing point close to or below room temperature.
These media can be transferred from a cholesteric state, where they show a selective reflection colour, into the colourless and transparent isotropic state by increasing the temperature.
One aim of the invention is to provide a CLC medium which has the above mentioned required properties.
A further aim of this invention is to provide an advantageous use of a 30 CLC medium according to this invention.
Further aims of this invention relate to LC displays, lasing and fluoresecence devices, decorative and security products and temperature indicators comprising a CLC medium according to the 35 present invention with improved properties.
- 5 Other aims of the present invention are immediately evident to the person skilled in the art from the following detailed description.
It has now been found that the above aims can be achieved by using 5 CLC media according to the present invention.
Summarv of the Invention The invention relates to a liquid-crystalline (LC) medium with a 10 helically twisted phase comprising a nematic component and an optically active component, characterized in that the LO medium has a clearing point of 50 C or less, and 15 the optically active component comprises one or more chiral compounds at least one of which is selected of formula I (Y') MU' V'XW' 1
(y2) MU' v2 w2 wherein X4, X2, Y' and y2 are independently of each other H. F. Cl, Br, I, ON, 30 SON, SF5, straight chain or branched alkyl with up to 25 C atoms which may be unsubstituted, mono- or poly substituted by F. Cl, Br, I or ON, it being also possible for one or more non-adjacent CH2 groups to be replaced, in each case independently from one another, by -O-, -S-, 35 -NH-, -NR -, -CO-, -COO-, -OCO-, -OCO-O-, -S-CO-,
- 6 -CO-S-, -CH=CH- or -C-C- in such a manner that O and/or S atoms are not linked directly to one another, a polymerizable group, or cycloalkyl or aryl with up to 20 C atoms that is optionally mono- or polysubstituted by L or by 5 a polymerizable group, R is H or alkyl with 1 to 4 C atoms, x' and x2 are independently of each other 0, 1 or 2, y, and y2 are independently of each other 0, 1, 2, 3 or 4, B and C are independently of each other an aromatic or partially or fully saturated aliphatic sixmembered ring, wherein 15 one or more CH groups may be replaced by N and one or more CH2 groups may be replaced by O and/or S. one of W' and w2 is -Z,-A'-(Z2-A2)m-R and the other is R* or A*, or both of W' and w2 are -Z'A4-(Z2-A2)m-R, with W' and w2 not being 20 at the same time H. or W' >0 Z'-A'-(Z2-A2)m-R 25 or >Z4-A'-(Z2-A2)m-R U. and u2 are independently of each other CH2, O. S. CO or CS, 30 V' and v2 are independently of each other (CH2)n, wherein up to four non-adjacent CH2-groups may be replaced by O and/or S. and one of V' and V2, or, in case 35 Xw2)=(}Z'-A'-(Z2-A2)mR, one or both of V' and v2 may also denote a single bond,
- 7 n is an integer from 1 to 7, Z' and Z2 are independently of each other-Or, -S-, -CO-, -COO-, 5 -OCO-, -O-COO-, -CO-NR -, -NR -CO-, -OCH2-, -CH2O-,
-SC H2-, -C H2S-, -C F2O-, -OC F2-, -C F2S-, -SC F2-,
-CH2CH2-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=N-,
-N=CH-, -N=N-, -CH=CH-, -CF=CH-, -CH=CF-, -CF=CF-,
-C5C-, -CH=CH-COO-, -OCO-CH=CH- or a single bond, A4, A2 and A* are independently of each other 1,4-phenylene in which, in addition, one or more CH groups may be replaced by N. 1,4-cyclohexylene in which, in addition, one or two non-adjacent CH2 groups may be replaced by O and/or S. 15 1,3-dioxolane-4,5-diyl, 1,4-cyclohexenylene, 1,4-bicyclo (2,2,2)octylene, piperidine-1,4-diyl, naphthalene-2,6-dlyl, decahydronaphthalene2,6-dlyl, or 1,2,3,4 tetrahydronaphthalene-2,6-diyl, it being possible for all these groups to be unsubstituted, mono- or 20 polysubstituted with L, and A, may also be a single bond, is halogen or a cyano, nitro, alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl group with 1 to 7 C atoms, wherein one or more H atoms may be substituted by F or Cl, m is in each case independently 0, 1, 2 or 3, and R and R* are independently of each other H. F. Cl, Br, I, CN, SCN, OH, SF5, straight chain or branched alkyl with up to 25 C 30 atoms which may be unsubstituted, mono- or polysubstituted by F. Cl, Br, I or CN, it being also possible for one or more non-adjacent CH2 groups to be replaced, in each case independently from one another, by -O-, -S-, -N H-, -N R -, -CO-, -COO-, -OCO-, -OCO-O-, 35 -S-CO-, -CO-S-, -CH=CH- or-C9C- in such a manner
- 8 that O and/or S atoms are not linked directly to one another. The invention further relates to the use of LC media according to the 5 present invention in LC displays, in particular bistable displays such as flexoelectric or cholesteric displays like SSCT and PSCT displays, for losing and fluorescence applications such as telecommunication applications like waveguides and high resolution filters, photonic crystal lasers, switches, backlights and LED type applications, for 10 diagnostics, temperature indicators, decorative or security applications like security markings or security threads for authentification of objects or documents of value.
The invention further relates to temperature indicators, product 15 labels, and false-proof, identification or authentification labels, markings or devices comprising an LC medium as described above and below.
The invention further relates to an object, product or document of 20 value comprising a temperature indicator, label, marking or device as described above and below.
The invention further relates to an LC display, in particular a bistable display such as a flexoelectric, cholesteric, SSCT or PSCT display, 25 comprising a CLC medium as described above and below.
The invention further relates to a lasing or fluorescence device, a temperature indicator or security or identification marking comprising a CLC medium as described above and below.
Detailed Description of the Invention
Especially preferred are LC media wherein the nematic component comprises one or more compounds selected from the group 35 comprising compounds of formulae 11 and lil
- 9 - R1 {:Z1 {: R2 11
5 R1 {)Z2 {:X
wherein 10 R1 and R2 are independently of each other H. alkyl, alkenyl or alkoxy having 1 to 15 carbon atoms which is unsubstituted, monosubstituted by ON or CF3 or mono- or polysubstituted by halogen, where one or more CH2 groups in these radicals may also, in each case 15 independently of one another, be replaced by -O-, -S-, -CO-, -CO-O-, - O-CO-, -O-CO-O- or -C_Cin such a way that oxygen atoms or sulfur atoms are not linked directly to one another, 20 4, and are independently of each other L' { - or {I L2 and may also denote O,N 30 {On or tN - ' and may also denote 4, Z. and Z2 are -COO-, -CH2CH2-, -CH=CH-, -C_C- or a single bond,
i - 10 L' and L2 are independently of each other, H or F, and X is ON, Cl, F or halogenated alkyl, alkoxy or alkenyl with 1 5 to6C atoms.
Preferably the LO media comprise at least one compound of formula 11. Further preferred are LO media comprising at least one compound of formula 11 and at least one compound of formula lilt The compounds of formula 11 are preferably selected from the following formulae 15 R' COO{} R2 Ha R'R llb R OR no 25 R' {:COO{}R2 lid R' R lie Rut}COO{} R2 llf { N){> R2 11g
- 11 {OR2 lih R'{R2 Ill F F R1R2 lik 15 R1 3cooR2 llm R R2 fin wherein R' and R2 are as defined in formula 11.
Preferred compounds of formulae Ha to He are those wherein R. and 25 R2 are straight chain alkyl having 1 to 12, very preferably 1 to 8, carbon atoms. Further preferred compounds of formulae Ha to He are those wherein R' is straight chain alkyl and R2 is straight chain alkoxy, each having 1 to 12, very preferably 1 to 8, carbon atoms.
30 Further preferred are compounds of formulae Ha to He wherein at least one of R' and R2 is alkenyl with 2 to 11, preferably 2 to 7, C atoms. Especially preferred are compounds of formula llb and He wherein R' is alkenyl with 2 to 7 C atoms and R2 is alkyl with 1 to 8 C atoms or alkenyl with 2 to 7 C atoms.
Especially preferred are compounds of formula Ha and lib.
- - 12
X in formula lil is preferably ON, F. Cl, CF3, OCF3 or OCHF2, very preferably ON or F. 5 The compounds of formula lil are preferably selected from the following formulae L1 10 R {ON Illa L2 15 R1 CN Illb L2 R1 {a} COO {ON 11 Ic L2 L1 R1 {:-COO{CN Illd L2 R1 3-CN Ille L1 lilt { NCN
- 13 {): F Ilig N L Ilih { IN R1 {OF 111i wherein R1 is as defined above and is preferably straight-chain alkyl 15 or alkoxy having 1 to 8 carbon atoms, and L1 and L2 are H or F. Particular preferred compounds of formulae Illa to Ilid are those wherein L' and L2 are H. Further preferred compounds of formulae Illa to Ilid are those wherein L1 is F and L2 is H or F. in particular H. Especially preferred are compounds of formula Illa, Illb and Illc.
The chiral compounds of formula I enable a high twist in the LC media according to the present invention even when used in small 25 amounts. The use of the compounds of formula 11 and/or 111 in the LC media according to the invention results in a high polarity and a high An value.
Furthermore, the LC media according to the present invention have 30 the following advantages: - they have a cholesteric phase at low temperatures and a low clearing point, - they have a high UV stability, 35 - they have a high stability at low temperatures,
- 14 - they have a low temperature dependence of the reflection wavelength d\/dT The compounds of formula 11 and lil have a broad range of 5 application. Depending on the choice of substituents, these compounds can serve as base materials of which the LC media are predominantly composed; however, it is also possible to add compounds of formula 11 and lil to LC base materials from other classes of compounds in order, for example, to modify the dielectric 10 and/or optical anisotropy of a medium of this type and/or to optimize its viscosity. In the pure state, the compounds of formula 11 and lil are colourless and form LC mesophases in a temperature range which is favourably located for the desired use. They are stable chemically, thermally and to light.
Preferred LC media additionally comprise one or more compounds selected from the group consisting of the bicyclic compounds of the following formulae R'CH2CH2{} R2 IV1
R'}R IV2
R'{R2 IV3
30 R'{:CH2CH2{ j R2 IV4 R'{}CH=CH R2 IV5
- 15 in which R' and R2 have one of the meanings given in formula 11, and are particularly preferably straight-chain alkyl or alkoxy having 1 to 12 carbon atoms.
5 In another preferred embodiment, the LC medium additionally comprises one or more 3-ring compounds selected from the group comprising compounds of the following formulae L' 10 R At _ _ Rex V R V -X Vl 20 L1 L1
R X Vl1 L' R -(3{ X Vl I I wherein R has one of the meanings of R' in formula 11, L, and L2 are as defined in formula 11, and X is F. Cl or halogenated alkyl, alkoxy or alkenyl with 1 to 6 C atoms.
The compounds of formulae V, Vl and Vll are preferably selected from the following formulae
- 16 R X Va R X Vb 10 F F F R X Vc 15 F
F F 20 R t: ( X Vd F F R I_ X Ve F F 30 R = X Vla R X Vlb
- 17 F F R AX Vlla F F F R -X Vllb F F R {}{ '$X Vllc wherein R is as defined above and is preferably straight-chain alkyl or alkoxy having 1 to 8 carbon atoms, and X is as defined above 20 and is preferably F. Cl or OCF3.
Particularly preferred compounds of formula I are those wherein - at least one, preferably both, of the radicals B and C are an 25 aromatic ring, at least one, preferably both, of the radicals B and C contain two saturated carbon atoms, - at least one, preferably both, of the radicals B and C contain four saturated carbon atoms, - at least one, preferably both, of the radicals U' and u2 are O. - V' and v2 are (CH2)n in which n is 1, 2, 3 or 4, and preferably one of the radicals V, and v2 is CH2 and the other is CH2 or (CH2)2, - one of the radicals V' and v2 is CH2 and the other is a single 35 bond'
- 18 - at least one of the radicals Z, and z2 is -CF2O-, -OCF2- or CF2CF2-,
- Z. is a single bond, 5 - at least one of the radicals Z. and z2 is CF2O-, -OCF2-, -CF2CF2- or -CF=CF- and the others are -COO-, -OCO-, -CH2CH2- or a single bond, - at least one of the radicals Z. and z2 is -C-C-, W1 Z'-A1-(z2-A2)m-R' or >Z'-A'-(Z2-A2)m-R and m is 0 or 1, in particular 0, preferably m is 0 and A' is a single bond, - W' is R* or A*, in particular H or F. and w2 is Z4-A'-(Z2-A2)m-R4, in 20 which m is 1 or 2, x' and x2 are 1, - y' and y2 are 1, - x',x2,y'andy2areO, 25 - R1 is straight-chain alkyl having 1 to 12 carbon atoms, where one or more hydrogen atoms may also be replaced by F or ON and where one or more nonadjacent CH2 groups may also, in each case independently of one another, be replaced by -O-, -S-, -NH-, -N(CH3)-, -CO-, -COO-, -OCO-, -OCO-O-, -SCO-, -CO-S-,
30 -CH=CH- or -C_C- in such a way that oxygen atoms and/or sulfur atoms are not linked directly to one another, particularly preferably alkyl or alkoxy having 1 to 12 carbon atoms, - X', x2, y', y2 and R* are selected from H. F and straight-chain alkyl 35 having 1 to 12 carbon atoms, where one or more hydrogen atoms may also be replaced by F or CN and where one or more non adjacent CH2 groups may also, in each case independently of one
- 19 another, be replaced by-O-, -S-, -NH-, -N(CH3)-, -CO-, -COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, -CH=CH- or-C_C- in such a way that oxygen atoms and/or sulfur atoms are not linked directly to one another, and are particularly preferably H. F or alkyl or alkoxy 5 having 1 to 12 carbon atoms, - X', X2, Y' and y2 are selected from aryl, preferably phenyl which may be unsubstituted or mono- or polysubstituted by L, preferably monosubstituted in 4 position, 10 - L is F. Cl, CN or optionally fluorinated alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl having 1 to 7 carbon atoms, - L is F. Cl, CN, NO2, CH3, C2H5, OCH3, OC2H5, COCH3, COC2H5, CF3, CHF2, CH2F, OCF3 OCHF2, OCH2F or OC2F5, - A* is 1,4phenylene or 1,4-cyclohexylene which may also be 15 substituted by up to 5, preferably by 1, 2 or 3 F or Cl atoms, CN or NO2 groups or alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl groups having 1 to 4 carbon atoms, where one or more hydrogen atoms may also be replaced by F or Cl, 20 - A' and A2 are selected from 1,4-phenylene and trans-1,4 cyclohexylene which groups may be unsubstituted or substituted by up to 4 L radicals, - the mesogenic group Z4-A'-(Z2-A2)m contains one, two or three five- or six-membered rings, 25 - the mesogenic group Z'-A4-(Z2-A2)m is bicyclohexyl, biphenyl, phenylcyclohexyl, cyclohexylphenyl or biphenylcyclohexyl, where the phenyl rings may also be substituted by one or two fluorine atoms. 30 The mesogenic group -Z4-A,-(Z2-A2)m in formula I is preferably selected from the following subformulae or their mirror images. Here Phe is 1,4-phenylene which may be substituted by one or more L groups, and Cyc is 1,4-cyclohexylene. Z is, independently at each occurrence, as defined above for Z'.
35 -Phe
- 20 -Cyc -Phe-Z-Phe -Phe-Z-Cyc -Cyc-Z-Cyc 5 -Phe-Z-Phe-Z-Phe -Phe-Z-PheZ-Cyc -Phe-Z-Cyc-Z-Phe -Cyc-Z-Phe-Z-Cyc -Cy>Z-Cyc-Z-Phe 1 0 -CyGZ-CyGZCYG L is preferably F. Cl, CN, NO2, CH3, C2H5, OCH3, OC2H5, COCH3, COC2H5, CF3, CHF2, CH2F, OCF3, OCHF2, OCH2F, OC2F5, in particular F. Cl, CN, CH3, CHF2, C2H5, OCH3, OCHF2, CF3 or OCF3, 15 very particularly preferably F. CH3, CF3, OCH3, OCHF2 or OCF3.
Particularly preferred compounds of formula I are the following 20 6o la to R R l b 35 RZR IC
- 21 5 OR Id BRIAR le 15 OCF2CF2R If j R.ZR 19 30 R*Z}R In
- 22 RZR li 10 R*>Z =R Ik ZOCF2{R Im $R.ZocF{}R In lo 30 to R
- 23 5 At; Ip 10 RtR Iq 15 \ 25 4 0 is :0} 30 m: FIR fO
- 24 jR'R IU 10 OUR IV
in which R. R* and Z' are as defined in formula 1, R' and R" have one of the meanings of R in formula 1, and L' and L2 are H or have one of the meanings of L in formula 1.
In these preferred formulae, L' and L2 are preferably H or F. R* is preferably H or F. R' and R" are preferably H. F. alkyl or alkoxy having 1 to 12 carbon atoms. R" is particularly preferably CH3.
25 Particular preference is given to compounds of the following formulae WAR ib1
- 25 T To} Ic1 wherein R is alkyl with 1 to 8 C-atoms and Z. is -COO-, OCO- or a single bond, preferably a single bond.
10 The optically active component comprises one or more chiral compounds, preferably selected of formula 1, of which the twisting power and concentration are selected such that the helical pitch of the LC medium is smaller than 1 m.
15 The proportion of the optically active component in the LC medium according to the invention is preferably 20%, in particular < 10%, particularly preferably from 0.5 to 8%, very particularly preferably from 1 to 5%. The optically active component preferably comprises from 1 to 6, in particular 1, 2, 3 or 4 chiral compounds.
The helical pitch of the LC medium according to the present invention is preferably from 130 nm to 1000 nm, in particular from 200 nm to 750 nm, particularly preferably from 200 nm to 400 nm.
25 The helical pitch is preferably chosen such that the medium reflects light in the visible wavelength range. The term "visible wavelength range" or "visible spectrum" typically comprises the range of wavelengths from 400 to 800 nm. Above and below, this term is also 30 meant to encompass the wavelength range from 200 to 1200 nm including the ultraviolet UV and infrared (JR) range and the far UV and far IR range.
The reflection wavelength of the LC medium according to the present 35 invention is preferably in the range from 200 to 1500 nm, in particular from 300 to 1200 nm, particularly preferably from 350 to 900 nm, very particularly preferably from 400 to 800 nm. Preference is
- 26 furthermore given to LC media having a reflection wavelength of from 400 to 700 nm, in particular from 500 to 600 nm.
Preferably the colour change of the LC media according to the 5 present invention is small over the operating temperature range.
Especially preferred are LC media according to the present invention that have a cholesteric phase (CLC media) with a clearing point (cholesteric isotropic phase transition temperature) of 50 C or less, 10 preferably 30 C or less, very preferably 25 C or less, most preferably 10 C or less. The clearing point is preferably in the range from -20 to 50 C, very preferably from -10 to 35 C, most preferably from O to 20 C.
15 The LC media preferably have dielectric anisotropy values As 2 5, preferably 210, in particular > 15, and birefringence values An > 0.12, preferably > 0.15.
The chiral dopants should preferably have a high helical twisting 20 power (HTP) with low temperature dependence. They should furthermore have a good solubility in the nematic component and not impair the liquid- crystalline properties of the LC medium, or impair them only to a small extent. They can have the same or the opposite orientation of rotation and the same or the opposite temperature 25 dependence of the twist.
Particular preference is given to dopants having an HTP of 20 m' or more, in particular of 40,um' or more, particularly preferably of 70 m' or more.
In LC media according to the present invention especially the chiral dopants of formula I exhibit a good solubility in the nematic component and induce a cholesteric structure having a high twist.
For this reason, it is possible to obtain novel LC media which have 35 reflection colours in the visible wavelength range having a high brilliancy, and have good stability at low temperatures, even when
- 27 only one of these dopants is used in low amounts. This is a significant advantage over CLC media of the prior art which usually require
large amounts of dopants to achieve reflection in the visible range.
5 A particularly preferred embodiment of the invention therefore relates to an LO medium as described hereinbefore and hereinafter, in which the chiral component consists of one chiral compound of formula 1, preferably in an amount of 15 % or less, in particular 10 % or less, particularly preferably 5 % or less.
In addition to the compounds of formula 1, the optically active component may also comprise one or more further chiral dopants, like for example cholesterol nonanoate (CN), C15, CB15, R- or S 811, R- or S-1011, R- or S2011, or R- or S-3011 (available from 15 Merck KGaA, Darmstadt). Especially suitable and preferred additional chiral dopants are derivatives of isosorbitiol, isomannitol or isoiditol, in particular dianhydrosorbide derivatives as described in WO 98/00428, chiral ethanediols such as diphenylethanediol (hydrobenzoin), in particular mesogenic hydrobenzoin derivatives as 20 described in GB-A-2 328 207, chiral binaphthol acetal derivatives as described in WO 02/34739, chiral TADDOL derivatives as described in WO 02/06265, and chiral dopants having at least one fluorinated bridging group and a terminal or central chiral group as described in WO 02/06196 and WO 02/06195.
In particularly preferred embodiments the LO medium comprises: - one or more, preferably 1 or 2 chiral compounds of formula la, lb or Ic, very preferably of formula Ib1 or Ic1, - 0.1 to 10 %, preferably 0.5 to 8 %, very preferably 1 to 5 % of chiral compounds of formula 1, - 20 % or less, preferably 10% or less, very preferably 0.5 % to 8 35 % of the optically active component,
- 28 1 to 10, preferably 2 to 8 compounds of formula 11, one or more, preferably 2 to 6 compounds of formula lla, preferably wherein R' and R2 are straight chain alkyl with 1 to 8 5 C atoms, the proportion of these compounds is preferably 15 to 60 %, very preferably 30 to 50 % of the nematic component, - one or more, preferably 1 to 4 compounds of formula lib, preferably wherein R' and R2 are straight chain alkyl with 1 to 8 10 C atoms, the proportion of these compounds is preferably 10 to 50 %, very preferably 20 to 40 % of the nematic component, - one or more, preferably1 to 5 compounds of formula 11 wherein R' is straight chain alkyl with 1 to 8 C atoms and R2 is straight 15 chain alkoxy with 1 to 8 C atoms, preferably in a proportion of up to 50 % of the nematic component; these compounds are preferably selected of formula Ha and/or lid; LC media comprising these compounds have higher clearing points, 20 - 1 to 8, preferably 2 to 6 compounds of formula lil, - one or more, preferably 1 to 5 compounds of formula lila, preferably wherein L' and L2 are H. the proportion of these compounds is preferably 10 to 50 %, very preferably 20 to 40 % 25 of the nematic component, - one or more, preferably 1 to 5 compounds of formula lilb, preferably wherein L' and L2 are H. the proportion of these compounds is preferably 5 to 40 %, very preferably 8 to 30 % of 30 the nematic component, - one or more, preferably 1 to 5 compounds of formula Tic, preferably wherein L' and L2 are H. further preferably wherein L' is F and L2 is H or F. very preferably H. the proportion of 35 these compounds is preferably 5 to 50 %, very preferably 10 to 40 % of the nematic component,
- 29 - one or more, preferably 1 to 5 compounds of formula lil wherein R' is straight chain alkyl with 1 to 8 C atoms, L' is F and L2 is H or F. preferably H. preferably in a proportion of up to 50 % of 5 the nematic component; these compounds are preferably selected of formula Illa; mixtures comprising these compounds have particularly low clearing points, - a nematic component comprising 15 to 80 %, preferably 20 to 65 10 % of one or more compounds of formula 11, a nematic component comprising 10 to 75 %, preferably 15 to 55 % of one or more compounds of formula lil, 15 a nematic component comprising in total 65 to 100 % of compounds of the formulae 11 and lil, - a nematic component essentially consisting of compounds selected from formulae 11, lil and IV.
The optimum weight ratio of compounds of the formulae I to IV largely depends on the desired properties, on the choice of the components of the formulae I to IV and on the choice of any other components which may be present. Suitable weight ratios within the 25 range given above can easily be determined from case to case.
In the abovementioned formulae I to IV, the term "fluorinated alkyl or alkoxy having 1 to 3 carbon atoms" preferably means CF3, OCF3, CFH2, OCFH2, CF2H, OCF2H, C2F5, OC2F5, CFHCF3, CFHCF2H,
30 CFHCFH2, CH2CF3, CH2CF2H, CH2CFH2, CF2CF2H, CF2CFH2,
OCFHCF3, OCFHCF2H, OCFHCFH2, OCH2CF3, OCH2CF2H,
OCH2CFH2, OCF2CF2H, OCF2CFH2, C3F7 or OC3F7, in particular CF3, OCF3, CF2H, OCF2H, C2F5, OC2F5, CFHCF3, CFHCF2H,
CFHCFH2, CF2CF2H, CF2CFH2, OCFHCF3, OCFHCF2H,
35 OCFHCFH2, OCF2CF2H, OCF2CFH2, C3F7 or OC3F7, particularly preferably OCF3 or OCF2H.
- 30 The term "alkyl" encompasses straight-chain and branched alkyl groups having 1-7 carbon atoms, particularly the straight-chain groups methyl, ethyl, propyl, butyl, pentyl, hexyl and heptyl. Groups 5 having 2- 5 carbon atoms are generally preferred.
The term "alkenyl" encompasses straight-chain and branched alkenyl groups having 2-7 carbon atoms, in particular the straight-chain groups. Particularly preferred alkenyl groups are C2-C7-1 E-alkenyl, 10 C4-C7-3Ealkenyl, C5-C7-4-alkenyl, C6-C7-5-alkenyl and C7-6-alkenyl, in particular C2-C7-1 E-alkenyl, C4-C7-3E-alkenyl and C5-C7-4-alkenyl.
Examples of preferred alkenyl groups are vinyl, 1 E-propenyl, 1 E-butenyl, 1 E-pentenyl, 1 E-hexenyl, 1 E-heptenyl, 3-butenyl, 3E-pentenyl, 3Ehexenyl, 3E-heptenyl, 4-pentenyl, 4Z-hexenyl, 15 4E-hexenyl, 4Z-heptenyl, 5-hexenyl, 6-heptenyl and the like. Groups having up to 5 carbon atoms are generally preferred.
The term "fluoroalkyl" preferably encompasses straight-chain groups with terminal fluorine, i.e. fluoromethyl, 2-fluoroethyl, 3-fluoropropyl, 20 4fluorobutyl, 5-fluoropentyl, 6-fluorohexyl and 7-fluoroheptyl. Other positions of fluorine are not precluded, however.
The term "oxaalkyl" preferably encompasses straight-chain radicals of the formula CnH2n±O-(CH2)m, where n and m are each, 25 independently of one another, from 1 to 6. Preferably, n = 1 and m is 1 to6.
Halogen is preferably F or Cl, in particular F. 30 If one of the abovementioned radicals is an alkyl radical and/or an alkoxy radical, this can be straight-chain or branched. It is preferably straight-chain, has 2, 3, 4, 5, 6 or 7 carbon atoms and accordingly is preferably ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy or heptoxy, furthermore methyl, octyl, nonyl, 35 decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy,
- 31 octoxy, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy or tetradecoxy. Oxaalkyl is preferably straight-chain 2-oxapropyl (= methoxymethyl), 5 2(= ethoxymethyl) or 3-oxabutyl (= 2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl, or 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.
10 If one of the abovementioned radicals is an alkyl radical in which one CH2 group has been replaced by -CH=CH-, this can be straight-chain or branched. It is preferably straight-chain and has 2 to 10 carbon atoms. Accordingly, it is in particular vinyl, prop-1- or prop-2-enyl, but-1-, 2- or but-3-enyl, pent-1-, -2-, -3- or pent-4-enyl, hex-1-, -2-, 15 -3-, 4- or hex-5-enyl, inept-1-, -2-, -3-, -4-, -5- or hept-6-enyl, oct-1-, -2, -3-, -4-, -5-, -6- or oct-7-enyl, non-1-, -2-, -3-, -4-, -5-, -6-, -7or non-8-enyl, dec-1-, -2-, -3-, -4-, -5-, -6-, -7-, -8- or dec-9-enyl.
If one of the abovementioned radicals is an alkyl radical in which one 20 CH2 group has been replaced by -O- and one has been replaced by -CO-, these are preferably adjacent. These thus contain an acyloxy group -CO-Oor an oxycarbonyl group -O-CO-. These are preferably straight-chain and have 2 to 6 carbon atoms.
25 They are accordingly in particular acetyloxy, propionyloxy, butyryloxy, pentanoyloxy, hexanoyloxy, acetyloxymethyl, propionyloxymethyl, butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl, 2-propionyl oxyethyl, 2-butyryloxyethyl, 3-acetyloxypropyl, 3-propionyloxypropyl, 4acetyloxybutyl, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, 30 butoxycarbonyl, pentoxycarbonyl, methoxycarbonylmethyl, ethoxy carbonylmethyl, propoxycarbonylmethyl, butoxycarbonylmethyl, 2(methoxycarbonyl)ethyl, 2-(ethoxycarbonyl)ethyl, 2-(propoxy carbonyl) ethyl, 3-(methoxycarbonyl)propyl, 3-(ethoxycarbonyl)propyl or 4(methoxycarbonyl)butyl.
- 32 If one of the abovementioned radicals is an alkyl radical in which one CH2 group has been replaced by unsubstituted or substituted -CH=CHand an adjacent CH2 group has been replaced by CO or CO-O or O-CO, this can be straight-chain or branched. It is 5 preferably straight-chain and has 4 to 13 carbon atoms. Accordingly, it is in particular acryloyloxymethyl, 2-acryloyloxyethyl, 3-acryloyloxy propyl, 4acryloyloxybutyl, 5-acryloyloxypentyl, 6-acryloyloxyhexyl, 7acryloyloxyheptyl, 8-acryloyloxyoctyl, 9-acryloyloxynonyl, 10acryloyloxydecyl, methacryloyloxymethyl, 2-methacryloyloxyethyl, 10 3methacryloyloxypropyl, 4-methacryloyloxybutyl, 5-methacryloyloxy pentyl, 6-methacryloyloxyhexyl, 7-methacryloyloxyheptyl, 8-methacryloyloxyoctyl or 9-methacryloyloxynonyl.
If one of the abovementioned radicals is an alkyl or alkenyl radical 15 which is monosubstituted by ON or CF3, this radical is preferably straight-chain. The substitution by ON or CF3 is in any position.
If one of the abovementioned radicals is an alkyl or alkenyl radical which is at least monosubstituted by halogen, this radical is 20 preferably straight-chain and halogen is preferably F or Cl. In the case of polysubstitution, halogen is preferably F. The resulting radicals also include perfluorinated radicals. In the case of monosubstitution, the fluoro or chloro substituent can be in any desired position, but is preferably in the co-position.
Compounds containing branched pendent groups may occasionally be of importance owing to better solubility in the conventional liquid crystalline base materials. However, they are particularly suitable as chiral dopants if they are optically active.
Branched groups of this type generally contain not more than one chain branch. Preferred branched radicals are isopropyl, 2-butyl (= 1methylpropyl), isobutyl (= 2-methylpropyl), 2-methylbutyl, isopentyl (= 3methylbutyl), 2-methylpentyl, 3-methylpentyl, 35 2-ethylhexyl, 2propylpentyl, isopropoxy, 2-methylpropoxy,
- 33 2-methylbutoxy, 3-methylbutoxy, 2-methylpentoxy, 3-methylpentoxy, 2ethylhexoxy, 1-methylhexoxy or 1-methylheptoxy.
If one of the abovementioned radicals is an alkyl radical in which two 5 or more CH2 groups have been replaced by -O- and/or -CO-O-, this can be straight-chain or branched. It is preferably branched and has 3 to 12 carbon atoms. Accordingly, it is in particular biscarboxymethyl, 2,2biscarboxyethyl, 3,3-biscarboxypropyl, 4,4-bis carboxybutyl, 5,5biscarboxypentyl, 6,6-biscarboxyhexyl, 10 7,7-biscarboxyheptyl, 8,8biscarboxyoctyl, 9,9-biscarboxynonyl, 10,10-biscarboxydecyl, bis(methoxycarbonyl)methyl, 2,2-bis (methoxycarbonyl)ethyl, 3,3bis(methoxycarbonyl)propyl, 4,4-bis (methoxycarbonyl)butyl, 5,5bis(methoxycarbonyl)pentyl, 6,6-bis (methoxycarbonyl)hexyl, 7,7bis(methoxycarbonyl)heptyl, 8,8-bis 15 (methoxycarbonyl)octyl, bis(ethoxycarbonyl)methyl, 2,2-bis (ethoxycarbonyl)ethyl, 3,3bis(ethoxycarbonyl)propyl, 4,4-bis(ethoxy carbonyl)butyl or 5,5bis(ethoxycarbonyl)hexyl.
The individual compounds which can be used in the media according 20 to the invention are either known or can be prepared analogously to the known compounds.
The LC media which can be used in accordance with the invention are prepared in a manner conventional per se. In general, the 25 desired amount of the components used in a lesser amount is dissolved in the components making up the principal constituent, expediently 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 again 30 after thorough mixing, for example by distillation.
The LC media according to the invention may also comprise further additives such as one or more stabilizers or antioxidants.
35 The LC medium according to the present invention is particularly suitable for use in LC displays, in particular bistable displays such as
- 34 flexoelectric or cholesteric displays like SSCT and PSCT displays, for lasing and fluorescence applications such as telecommunication applications like waveguides and high resolution filters, photonic crystal lasers, switches, backlights and LED type applications, for 5 diagnostics, temperature indicators, decorative or security applications like security markings or security threads for authentification of objects or documents of value.
For example, an LO medium according to the present invention can 10 be used in a temperature indication or security, false-proof or verification marking or device operating in the visible spectrum of light, but also in the UV or IR region.
In the present application and in the following examples, the 15 structures of the liquid-crystal compounds are specified by acronyms, which are transformed into chemical formulae according to the following Tables A and B. All radicals CnH2n+' and CmH2m+' are straight-chain alkyl radicals having n or m C atoms. The coding according to Table B is selfevident. Table A specifies the acronym for 20 the parent body only. In individual cases, the acronym for the parent body is followed, separated therefrom by a hyphen, by a code for the substituents R', R2, L', L2 and L3: Code for R', R' R2 L' L2 L3 25 R2, L', L2, L3
nm CnH2n+1 CmH2m+1 H H H nOm CnH2n+10 CmH2m+1 H H H nO.m CnH2n+1 OCmH2m+ 1 H H H 30 n CnH2n+1 CN H H H n-N CnH2n+1 CN H H H nN.F CnH2n+1 CN F H H nN.F.F CnH2n+1 CN F F H 35 nF CnH2n+1 F H H H nOF OCnH2n+' F H H H
- 35 nF.F CnH2n+1 F F H H nmF CnH2n+1 CmH2m+1 H H F nOCF3/ nOT CnH2n+, OCF3 H H H 5 n-Vm CnH2n+1 CH=CHCmH2m+1 H H H nV-Vm CnH2n+, CH=CH CH=CHCmH2m+1 H H H nO-S CnH2n+10 NCS H H H nS.F.F CnH2n+1 NCS F F H 10 Preferred mixture components are shown in Tables A, B and C. Table A: (L1, L2, L3 = H or F) R1{ R2 R1} R2
PCH CCH
R {>COO{:R2 R1 R2
ME B 25 L' R1{} COO { R2 R1 {: COO {} R2
L2 D OS 1 L1 R {o)R2 {oR2 35 pyp PDX
- 36 Table B:
CnH2n+1 {I ON CnH2n+1 ON 5 Ken Man The following examples should illustrate the invention without limiting it.
Hereinbefore and hereinafter, percentages are given in per cent by 10 weight. All temperatures are specified in degrees Celsius. m.p. denotes melting point, cl.p. = clearing point. Furthermore, C = crystalline state, S = smectic phase, N = nematic phase, Ch = cholesteric phase and I = isotropic phase. The data between these symbols represent the transition temperatures. Furthermore, the 15 following abbreviations are used (unless indicated otherwise, the values refer to a temperature of 20 C).
An optical anisotropy at 589 nm ne extraordinary refractive index at 589 nm 20 As dielectric anisotropy en dielectric constant parallel to the longitudinal axes of the molecules it, rotational viscosity [mPa see] Max maximum reflection wavelength [nary] 25 AX reflection band width [nm], measured as full width at half maximum (FWHM) of the reflection band The helical twisting power HTP of a chiral compound which produces a helically twisted superstructure in a liquid-crystalline mixture is given 30 by the equation HTP = (pc)4 [my] in which p is the helical pitch of the helically twisted phase, given in m, and c the concentration of the chiral compound (for example, a c value of 0.01 corresponds to a concentration of 1% by weight). Unless otherwise indicated, HTP values hereinbefore and hereinafter refer to a temperature of 20 C 35 and the commercially available neutral nematic TN host mixture MLC 6260 (Merck KGaA, Darmstadt).
- 37 ExamoIe 1 The nematic host mixture N1 is formulated as follows PCH- 2 15.0 % cl.p. 9 C PCH-53 10.0 % An 0.15 ME15 15.0 % ne 1.65 ME35 15.0 % A 8.2
10 ME55 15.0 % ll 14.4 K6 10.0 %
K9 10.0 %
K12 10.0 %
15 Mixture N1 is doped with the chiral compound of formula Ib1a to give cholesteric mixture C1.
o C3H7 Ib1a Furthermore, mixture N1 is doped with the chiral dopants D1 and D2 25 known from prior art and disclosed e.g. in WO 98/00428, to give
cholesteric mixture C2.
CH3O {: COO {) COO o O OOC {} OOC {>OCH3
- 38 H,3C6 {} CO: o D2 O - OOC { - C6H13
The compositions of C1-C3 are shown in the table below | N1 | Ib1a | D1 | D2 10 C1 (invention) 97.42 /O 2.58 % C2 (comparative) 95.45 % 2. 00 2.55 % The cholesteric mixture C3 is formulated as follows 15 ME15 15. 80 % cl.p. 5 C ME35 18.55 %
ME55 9.30 %
ME105 10.30 %
ME22 5.16 %
20 CE9 40.89 %
CE9 is a chiral compound of the following formula 25 H7C3 {)COO{} CH2CH(CH3)C2H5 CE9
The cholesteric mixtures C1-C3 have a green reflection colour.
The reflection wavelengths NmaX of mixtures C1-C3 and the reflection 30 band width are shown in table 1 below.
C1 C2 C3
Temp. max (nary) AX (nary) max (nary) AX (nary) max (nary) (nary) - 20 C 547 63 562 65 530 50
-15 C 543 57 553 58 536 49
35 -10 C 539 52 545 61 539 48
-5 C 536 49 540 53 554 48
- 39 0 C 530 41 536 47 558 44
5 C 527 35 529 34 to l 5 The mixtures C1-C3 do not crystalline in the bulk at 5 C for in excess of 100 hours. C1 does not crystalline at -20 C and -40 C for in excess of 100 hours, whereas both C2 and C3 crystalline at-40 C within 100 hours and appear to crystalline at -20 C within this time but retain some of the green colour.
Figure 1 shows a plot of the maximum reflection wavelength Max Of mixtures C1-C3 as a function of temperature. The mixture C3 has the trend of increasing Max with temperature with a change Of Max of more than 30 nm. The mixture C2 with the prior art dopants D1 and
15 D2 shows the opposite effect, but still has a large temperature dependence of Max. The mixture C1 according to the present invention shows decreasing Max with increasing temperature, with a lower change of Max of only 20 nm.
20 C1 is therefore particularly suitable as temperature indicator.
Claims (16)
1. A liquid-crystalline (LC) medium with a helically twisted phase comprising a nematic component and an optically active component, s characterized in that the LC medium has a clearing point of 50 C or less and the optically active component comprises one or more chiral compounds 10 at least one of which is selected of formula I (Y)y1 (X)x1,.
MU-VXW2 1
15 (Y)y2 U V W wherein X,, X2, Ye and y2 are independently of each other H. F. C1, Br, I, CN, SCN,SFs, straight chain or branched alkyl with up to 25 C atoms which 25 may be unsubstituted, mono- or polysubstituted by F. C1, Br, I or CN,it being also possible for one or more non-adjacent CH2 groups to be replaced, in each case independently from one another, by -O, -S-, -NH -NR -,-CO-,-COO-,-OCO-,-OCO-O-,-S-CO-,-CO-S-,-CH=CH- or -C-Cin such a manner that O and/or S atoms are not linked directly to 30 one another, a polymerizable group, or cycloalkyl or aryl with up to 20 C atoms that is optionally mono- or polysubstituted by L or by a polymerizable group,
- 41 R is H or alkyl with 1 to 4 C atoms, x1 and x2 are independently of each other 0, 1 or 2, 5 y' and y2 are independently of each other 0, 1, 2, 3 or 4, B and C are independently of each other an aromatic or partially or fully saturated aliphatic six-membered ring, wherein one or more CH groups may be replaced by N and one or more CH2 groups may be replaced by O and/or S. one of W' and W2 is -Z'-A'-(Z2-A2)m-R and the other is R or A, or both of We and w2 are -Z'-A'-(Z2-A2)m-R, with W' and w2 not being at the same time H. or 15 W1 >Oz'-A'-(z2-A2)m-R or >Z'-A'-(Z2-A2)m-R Ui and u2 are independently of each other CH2, O. S. CO or CS, V' and v2 are independently of each other (CH2)n, wherein up to four non-adjacent CH2 groups may be replaced by O and/or S. and one of V' 25 and V2, or, in case W' ≥0 Z'-A'-(Z2-A2)m-R one or both of V' and v2 may also denote a single bond, n is an integer from 1 to 7,
- 42 Z and Z2 are independently of each other -O-, -S-, -CO-, -COO-, -OCO -O-COO-, -CO-NR -, -NR -CO-, -OCH2-, -CH2O-, -SCH2-, -CH2S-,
-CF2O-, -OCF2-, -CF2S-, -SCF2-, -CH2CH2-, -CF2CH2-, -CH2CF2-,
-CF2CF2-, -CH=N-, -N=CH-, -N=N-, -CH=CH-, -CF=CH-, -CH=CF-,
s -CF=CF-, -C_C-, -CH=CH-COO-, -OCO-CH=CH- or a single bond, A', A2 and A. are independently of each other 1,4-phenylene in which, in addition, one or more CH groups may be replaced by N. 1,4 cyclohexylene in which, in addition, one or two non-adjacent CH2 groups 10 may be replaced by O and/or S. 1,3-dioxolane-4,5-diyl, 1,4 cyclohexenylene, 1,4-bicyclo-(2,2,2) -octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, or 1,2,3,4 tetrahydronaphthalene-2,6-diyl, it being possible for all these groups to be unsubstituted, mono- or polysubstituted with L, and At may also be a 15 single bond, L is halogen or a cyano, nitro, alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl group with 1 to 7 C atoms, wherein one or more H atoms may be substituted by F or C1, m is in each case independently 0, 1,
2 or 3, and R and R are independently of each other H. F. Cl, Br, I, CN, SCN, OH, SFs, straight chain or branched alkyl with up to 25 C atoms which may be 25 unsubstituted, mono- or polysubstituted by F. Cl, Br, I or CN, it being also possible for one or more non-adjacent CH2 groups to be replaced, in each case independently from one another, by -O-, -S-, -NH-, -NR -, -CO-, -COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, -CH=CH- or-C_C in such a manner that O and/or S atoms are not linked directly to one 30 another.
- 43 2. A medium as claimed in claim 1, wherein the nematic component comprises one or more compounds of formula II R Z'{:R2 11
wherein Rl and R2 are independently of each other H. alkyl, alkenyl or alkoxy 10 having 1 to 15 carbon atoms which is unsubstituted, monosubstituted by CN or CF3 or mono- or polysubstituted by halogen, where one or more CH2 groups in these radicals may also, in each case independently of one another, be replaced by -O-, -S-, -CO-, -CO-O-, -OCO-, -O-CO-O- or -C_C- in such a way that oxygen atoms or sulphur atoms are not linked 15 directly to one another, and are independently of each other L' 20 or I. may also denote { or {ONE and may also denote.
Z' is -COO-, -CH2CH2-, -CH=CH-, -C_C- or a single bond, and Lo and L2 are independently of each other H or 15.
- 44
3. A medium as claimed in claim 1 or 2, wherein the nematic component comprises one or more compounds of formula III 5 R1 {Z2$._X 111
wherein 10 R1 is independently of each other H. alkyl, alkenyl or alkoxy having 1 to 15 carbon atoms which is unsubstituted, monosubstituted by CN or CF3 or mono- or polysubstituted by halogen, where one or more CH2 groups in these radicals may also, in each case independently of one another, be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- or -C_Cin 15 such a way that oxygen atoms or sulphur atoms are not linked directly to one another, and are independently of each other 20 L'
{ - or {I, 2s may also denote { or {O.
Z2 is -COO-, -CH2CH2-, -CH=CH-, -C-C- or a single bond, 30 L' and L2 are independently of each other H or F. and X is CN, Cl, F or halogenated alkyl, alkoxy or alkenyl with 1 to 6 C atoms.
- 45
4. A medium as claimed in claim 2 or 3, wherein the nematic component comprises one or more compounds of the following formulae s R'COO{: R2 lie R'{R lib R'3R kc R. {-COO{: R2 lid Is R' {I R lie 20 R'{:COO{:R2 lif R'{O)R2 kg { o>R2 fib R'}R2 1ii
- 46 R' {a R2 lit s F F R' {SCOOT R2 km F F R1{R2 lit 15 wherein R' and R2 have independently of each other one of the meanings of R1 in formula II.
5. A medium as claimed in any of claims 2 to 4, wherein the nematic component comprises one or more compounds of the following formulae 2s Rim t CN Illa
- 47 R' ON Illb R {)COO CN Illc L2 R' {a} COO {ON Ilid R'CN Ille L' Illf 20 R'{O >AN
R'{O IF lilg L Ilih { O)CN
R' F Illi
- 48 wherein Rl, Lo and L2 independently have the one of the meanings of Ri, Ll and L2, respectively, in formula II.
6. A medium as claimed in any of the preceding claims, which comprises 0. 1 s to 10 % of chiral compounds of formula I.
7. A medium as claimed in any of the preceding claims, wherein the optically active component consists of one chiral compound of formula I.
8. A medium as claimed in any of claims 2 to 7, wherein the nematic component comprises 15 to 80 % of one or more compounds of formula II.
9. A medium as claimed in any of claims 3 to 8, wherein the nematic 15 component comprises
10 to 75 % of one or more compounds of formula III. 10. A medium as claimed in any of the preceding claims, which has a reflection wavelength in the range from 400 to 800 nm.
11. A medium as claimed in any of the preceding claims, which has a clearing point in the range from -10 to 35 C.
12. A liquid-crystalline (LC) medium substantially as hereinbefore described 25 with reference to composition C1 in Example 1.
13. Use of an LC medium as claimed in any of the preceding claims for a decorative or security application, diagnostic, temperature indicator, lasing or fluorescence phenomenon or in an LC display, bistable display, 30 flexoelectric or cholesteric display, SSCT or PSCT display.
14. An LC display, bistable display, flexoelectric, cholesteric, SSCT or PSCT display comprising an LC medium as claimed in any of claims 1 to 12.
- 49
15. A lasing or fluorescence device, temperature indicator, product label, false-proof, identification or authentification label, marking or device comprising an LC medium as claimed in any of claims 1 to 12.
s
16. An object, product or document of value comprising a temperature indicator, label, marking or device as claimed in claim 15.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002034739A1 (en) * | 2000-10-20 | 2002-05-02 | Merck Patent Gmbh | Chiral binaphthol derivatives |
| WO2002094805A1 (en) * | 2001-05-21 | 2002-11-28 | Merck Patent Gmbh | Chiral compounds |
| WO2002100979A1 (en) * | 2001-06-13 | 2002-12-19 | Merck Patent Gmbh | Fluid crystalline medium and high-torsion liquid crystalline display device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2002034739A1 (en) * | 2000-10-20 | 2002-05-02 | Merck Patent Gmbh | Chiral binaphthol derivatives |
| WO2002094805A1 (en) * | 2001-05-21 | 2002-11-28 | Merck Patent Gmbh | Chiral compounds |
| WO2002100979A1 (en) * | 2001-06-13 | 2002-12-19 | Merck Patent Gmbh | Fluid crystalline medium and high-torsion liquid crystalline display device |
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| KR20150015416A (en) * | 2013-07-31 | 2015-02-10 | 가부시키가이샤 한도오따이 에네루기 켄큐쇼 | Binaphthyl compound, liquid crystal composition, liquid crystal element, and liquid crystal display device |
| JP2015044798A (en) * | 2013-07-31 | 2015-03-12 | 株式会社半導体エネルギー研究所 | Binaphthyl compound, liquid crystal composition, liquid crystal element, and liquid crystal display device |
| KR102320930B1 (en) | 2013-07-31 | 2021-11-04 | 가부시키가이샤 한도오따이 에네루기 켄큐쇼 | Binaphthyl compound, liquid crystal composition, liquid crystal element, and liquid crystal display device |
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