WO2002054141A2 - Materiaux pour cristaux liquides discotiques et films de compensation a plaque o realises a partir desdits materiaux - Google Patents

Materiaux pour cristaux liquides discotiques et films de compensation a plaque o realises a partir desdits materiaux Download PDF

Info

Publication number
WO2002054141A2
WO2002054141A2 PCT/US2002/000059 US0200059W WO02054141A2 WO 2002054141 A2 WO2002054141 A2 WO 2002054141A2 US 0200059 W US0200059 W US 0200059W WO 02054141 A2 WO02054141 A2 WO 02054141A2
Authority
WO
WIPO (PCT)
Prior art keywords
liquid crystal
group
discotic liquid
benzoic acid
crystal compound
Prior art date
Application number
PCT/US2002/000059
Other languages
English (en)
Other versions
WO2002054141A3 (fr
Inventor
Frank W. Harris
Stephen Z. D. Cheng
Original Assignee
The University Of Akron
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.)
Filing date
Publication date
Application filed by The University Of Akron filed Critical The University Of Akron
Priority to AU2002239812A priority Critical patent/AU2002239812A1/en
Publication of WO2002054141A2 publication Critical patent/WO2002054141A2/fr
Publication of WO2002054141A3 publication Critical patent/WO2002054141A3/fr

Links

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
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/32—Non-steroidal liquid crystal compounds containing condensed ring systems, i.e. fused, bridged or spiro ring systems
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3016—Polarising elements involving passive liquid crystal elements
    • 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
    • C09K19/32—Non-steroidal liquid crystal compounds containing condensed ring systems, i.e. fused, bridged or spiro ring systems
    • C09K2019/328—Non-steroidal liquid crystal compounds containing condensed ring systems, i.e. fused, bridged or spiro ring systems containing a triphenylene ring system

Definitions

  • LCD Liquid Crystal Displays
  • LCD technology offers widely known advantages over traditional display technologies such as cathode ray tubes. Among these advantages are low weight and low power consumption.
  • Liquid crystal displays have previously been considered to provide a narrower field of view than traditional display technologies, such as the previously mentioned cathode ray tubes.
  • Liquid crystal displays typically contain a plurality of liquid crystal cells.
  • Each liquid crystal (LC) cell generally contains a liquid crystal material sandwiched between two substrates. Located on either side of the liquid crystal material is a set of electrodes which are typically indium-tin oxide (ITO) or tin oxide.
  • ITO indium-tin oxide
  • a pair of polarizing filters is located outside of the substrates, with each filter on an opposite side of the liquid crystal cell.
  • the polarizers are oriented at right angles relative to each other. The orientation of the liquid crystal material in the cell determines whether light passes through each polarizer in the absence of external influence such as an electric field, thereby giving a transparent appearance, or whether light is blocked by one of the polarizers, thereby giving the cell a darkened appearance.
  • the orientation of the liquid crystal material is changed by the application of an electric field by the electrodes to alter light transmission through the cell.
  • the liquid crystal material is aligned such that the cell appears opaque or transparent absent an application of an electric field through the electrodes.
  • an electric field is applied to such a cell, the orientation of the liquid crystal UA387 2 material is altered in such a way as to prevent the transmission of light through the cell, making the cell appear darkened.
  • orientation of a liquid crystal material at its surface is dependent on the orientation of material it comes in contact with. It is known to coat the surface of a substrate with an agent which influences the orientation of a liquid crystal material that comes in contact with the coated substrate. Such coating agents are known as alignment layers. Optimally, an alignment layer material provides a uniform angle of orientation, also known as a pre-tilt angle. Various materials and methods have been used in establishing an alignment layer of a desired orientation. For example, it is known in the art that an alignment layer may comprise anisotropically absorbing molecules which can be oriented by exposure to polarized light.
  • Inorganic thin films such as metal oxide films, which have been deposited on a substrate at an oblique angle can also be used as alignment layers as disclosed in U.S. Patent No. 5,638,197. It is also known to use a polymeric alignment layer which can be oriented by means of a mechanical buffing process. In such a process, a polymer layer is applied to a substrate and is buffed with a cloth or other fibrous material. Liquid crystal material coming into contact with a surface treated in this way typically aligns itself parallel to the direction of buffing. Polyimides are frequently used as a polymeric alignment material for liquid crystal cells.
  • Polyimides may be used in optical compensator layers such as O-plate compensators.
  • Polyimides generally display good chemical stability and are easily deposited on a substrate and rubbed.
  • Polyimides are generally prepared by contacting a diamine with an acid anhydride, producing a polyamic acid. This polyamic acid may be coated onto a substrate and heat treated at about 150°- 230°C, converting the polyamic acid to a polyimide. The polyimide film is then mechanically rubbed as mentioned above.
  • LCDs frequently have a narrow field of view. It is frequently desirable to increase this field of view especially in applications such as computer displays, avionic displays and televisions.
  • the viewing zone of an LCD that is not equipped with an optical compensator is narrow UA387 3
  • Optical compensators have been used to increase the viewable angle of LCDs without negatively affecting image quality when viewed normal to the surface of the LCD.
  • Optical compensators typically take the form of an additional layer of liquid crystal material located between a polarizer and an analyzer within the LCD. This liquid crystal material may be given a specific orientation under the influence of an alignment layer material.
  • O-plate compensation films, or O-plate compensators are one type of optical compensator. O-plate compensators generally minimize reversal of gray levels and improve overall gray scale stability.
  • O-plate compensators have been previously described as comprising a positive birefringent material which has a principle optic axis oriented at an oblique angle relative to the surface of the liquid crystal layer.
  • An oblique angle includes any angle between 0° and 90°. In previous O-plate compensators, this angle has been provided in various ways.
  • U.S. Patent No. 5,619,352 describes an O-plate compensator which includes an alignment layer, a liquid crystal pretilt layer , and a liquid crystal compensator layer.
  • the described O-plate compensator depends on the liquid crystal pre-tilt layer to provide an adequate pre-tilt angle for the liquid crystal compensator layer because the alignment layer produces only a 1° to 10° liquid crystal pretilt angle at the alignment layer/liquid crystal pre-tilt layer interface.
  • the described O-plate compensator therefore depends on multiple layers of liquid crystal material to provide an adequate angle of orientation of the liquid crystal material.
  • a similar O- plate compensator is also described in U.S. Patent No. 5,986,734 and PCT Application No. WO 96/10770.
  • U.S. Patent No. 5,583,679 also describes an O-plate compensator for a liquid crystal display.
  • the O-plate compensator described in this patent comprises a transparent support and a discotic liquid crystal structural unit with a plane inclined from the plane of the support. This angle varies along the depth of the liquid crystal layer. It does not disclose an O-plate compensator with an angle of orientation that is independent of the thickness of the liquid crystal layer. It also UA387 4
  • U.S. Patent No.5,612,801 describes a "monolithic" O-plate compensator which comprises a plurality of layers that are deposited on a substrate.
  • the term "monolithic” means that one layer is deposited on another in assembling the compensator. Therefore, this patent does not disclose an O-plate compensator that is effective with a single alignment layer and a single liquid crystal material layer.
  • pre-tilt angle has frequently been used in the prior art to describe a final angle provided by a combination of an alignment layer and a liquid crystal layer.
  • no single polyimide alignment layer for a liquid crystal layer has provided a pre-tilt angle greater than about 15°.
  • O-plate compensators that provide a high angle of orientation in a single layer of liquid crystal material, independent of the thickness of that layer, have been previously unknown.
  • the present invention provides a photopolymerizable discotic liquid crystal compound comprising the general structure: UA387 5
  • a discotic liquid crystal compound having the above structure may be a component of a liquid crystal display optical compensator.
  • the present invention also provides a method of synthesizing a discotic liquid crystal compound.
  • a hydroxyalkyl benzoic acid is' alkylated with a halogenated alkyl alcohol to form a substituted benzoic acid.
  • the substituted benzoic acid is then hydrolyzed to generate a hydroxyl-terminated benzoic acid, and the hydroxyl-terminated benzoic acid is contacted with an acid chloride to generate a hydroxyalkyloxyl benzoic acid.
  • the hydroxyalkyloxyl benzoic acid is then contacted with a alkylhydroxy triphenylene compound to form a discotic liquid crystal compound.
  • the Figure is a schematic summary of a method of preparing a mesogenic group for attachment to a diamine to create a high pre-tilt polyimide alignment layer component of an O-plate compensator.
  • optical compensator for liquid crystal displays eliminates reversal of grey levels and improves gray scale stability.
  • the optical compensator of the present invention is comprised of an alignment layer that generates a high liquid crystal pretilt angle and a photopolymerizable discotic liquid crystal with the general structure shown below:
  • n is a positive integer.
  • n is between 6 and 11, and most preferably between 6 and 8.
  • R' is hydrogen or a methyl group.
  • the discotic LC molecules of the present invention possess characteristic intrinsic uniaxial negative birefringence.
  • the discotic LC molecules of the present invention may be useful as optical compensators in the absence of an alignment layer such as a C-plate compensator, for example.
  • the discotic LC molecules of the present invention may also be used in conjunction with an alignment layer to form other types of optical compensators. Alignment layers that generate a high liquid crystal (LC) pre-tilt angle are believed to be particularly useful in such compensator.
  • LC liquid crystal
  • the alignment layer provides a pre-tilt angle between about 5° and about 90°.
  • the alignment layer provides a pre-tilt UA387
  • the alignment layer provides a pre-tilt angle between about 20° and about 80°. In one particular example, the alignment layer provides a pre-tilt angle between about 40° and about 70°. In one particular embodiment, the discotic liquid crystal material of the present invention is used in an O-plate compensator.
  • An O-plate compensator according to the present invention is constructed by applying an alignment layer onto a substrate.
  • the polyimide may be solution or spin cast as a film onto a substrate.
  • Other alignment layer materials and methods of deposition may also be utilized.
  • the pre-tilt angle provided by the alignment layer is preferably greater than 20° and most preferably greater than or equal to 40°.
  • the discotic liquid crystal and a small amount of a photoinitiator is then solution or spin cast upon the alignment layer. After a heat treatment, the liquid crystal layer is crosslinked with UV light.
  • the liquid crystal of O-plate compensator of the present invention possesses a columnar discotic phase.
  • a preferred alignment layer is a polyimide comprising a reaction product of at least one dianhydride and at least one diamine, wherein the at least one diamine contains a pendent mesogenic group, and wherein the pendent mesogenic group.
  • the prndent mesogenic group is attached to the diamine by a linking group selected from the group consisting of an ester and an ether, and a methylene spacer.
  • Polyimides may be schematically represented by the structure
  • A is one or more residues from an acid dianhydride group and B is one or more residues from a diamine compound and n is a positive number.
  • n is a positive number.
  • polyimide polymers are prepared from appropriately substituted diamines. Suitable diamines are represented by formulas I and II below.
  • R ⁇ is an ester or ether linking group
  • R2 is a mesogenic group or a functional group as described below
  • x is a positive number.
  • R3 is hydrogen or a halogen.
  • x is between 6 and 18.
  • x is between 6 and 11.
  • x is 6.
  • R3 is bromine.
  • Mesogenic groups are groups with a rod-like molecular structure. That is, mesogenic groups, or simply mesogens, are groups UA387 9
  • Functional groups are those groups which allow one polyimide molecule to react with another molecule.
  • groups which permit the crosslinking of polyimide molecules within a layer are particularly preferred functional groups.
  • Suitable mesogenic and functional groups include the following structures.
  • X may be hydrogen or an organic group having from 1 to 20 carbon atoms and R4 may be an organic group selected from the group consisting of esters, ethers, groups containing a methylene subunit, groups containing a crosslinking subunit and groups containing a combination of any of these subunits.
  • Groups containing acrylate or methacylate subunits may be crosslinked such as by photopolymerization, for example.
  • the at least one dianhydride is 2,2'-bis-(3,4-dicarboxyphenyl)-l,l,l,3,3,3-hexafluoropropane UA387 10 dianhydride or dibromo-biphenyltetracarboxylic dianhydride, the substituentis not represented by formula V.
  • a mesogenic group shown in VI may be synthesized by the method as described below with reference to Figure 1.
  • Ethyl 4-hydroxybenzoic ester is alkylated with 6-chlorohexanol to produce intermediate (1).
  • Intermediate (1) is used in two different reactions. In the first reaction, the hydroxyl group of intermediate (1) is protected, using 3,4-dihydro-2- pyran (DHP) for example, forming intermediate (2).
  • Intermediate (2) is then hydrolyzed to form a THP -benzoic acid derivative (4).
  • intermediate (1) is hydrolyzed to generate a hydroxy terminated benzoic acid (3) .
  • the hydroxy terminated benzoic acid (3) is contacted with CH2CH2COCI in an organic solvent to form an intermediate (5).
  • Tert-butyl dimethylsilyl chloride (TBDMS) may be used to protect methyl hydroquinone.
  • TDMS Tert-butyl dimethylsilyl chloride
  • the desired isomer is isolated, by chromatography for example, and is then reacted with the THP-benzoic acid derivative (4) forming intermediate (6).
  • This reaction product is then selectively deprotected, for example, using tert-butylamonium fluoride (TBAF) in tetrahydrofuran (THF) , to form intermediate (7) .
  • TBAF tert-butylamonium fluoride
  • THF tetrahydrofuran
  • Mesogenic group (9) may be contacted with dinitro diphenic acid followed by tin (II) chloride reduction in ethanol to form a diamine of formula I.
  • a diamine may be used to prepare a polyimide alignment layer in an optical compensator of the present invention.
  • Mesogens within the class encompassed by V may be synthesized in the following manner.
  • 4-cyano-4'-hydroxybiphenyl may be contacted with a ⁇ - bromoalkanol in an Sj ⁇ 2 reaction in refluxing acetone over 3-4 days. This results in the production of a 4-( ⁇ -hydroxyalkoxy)-4'-cyanobiphenyl compound which may be further purified by recrystalization from ethanol.
  • 4-cyano-4'- hydroxybiphenyl may be contacted with an ,(f> alkanediol in a Mitsunobu reaction to form a 4-( ⁇ -hydroxyalkoxy)-4'-cyanobiphenyl compound.
  • Mitsunobu reaction may be purified by flash chromatography.
  • Mesogens within the class encompassed by IV may be synthesized by similar methods, by starting with a hydroxybiphenyl compound instead of 4-cyano-4'-hydroxybiphenyl.
  • mesogens may be used to produce mesogen-containing diamine compounds of formula I by coupling the mesogen with a dinitro diphenic acid using the standard dicyclohexylcarbodiimide (DCC)/DMAP procedure to produce a dinitro intermediate compound.
  • dinitro diphenic acid may be converted to 4,4'-dinitro-2,2'-biphenyl-carbonyl chloride by refluxing with thionyl chloride.
  • the mesogen may be contacted with 4,4'-dinitro-2,2'-biphenyl-carbonyl chloride in an organic solvent such as triethylamine or methylene chloride to produce a dinitro intermediate.
  • the dinitro intermediate may be reduced to form a diamine, by stannous chloride reduction or by reduction using hydrazine in an organic solvent at 80 °C, for example.
  • Mesogens of the present invention may also be coupled to brominated biphenylcarboxylic acids to produced brominated diamines of formula I.
  • Cyanuric acid is contacted with bromine and the resulting compound was used to brominate 4,4'-dinitro-2,2'-biphenyl-carboxylic acid yielding 6,6'-dibromo-2,2'- biphenylcarboxylic acid.
  • This brominated carboxylic acid may be coupled with a mesogen and reduced as described above to produce a brominated diamine.
  • Diamines of formula II may be synthesized by the following technique.
  • 3,5-dinitrobenzoic acid is esterified with n-octadecanol to afford n-octadecyl 3,5- dinitrobenzoate using DCC as a dehydration agent in dichloroethane.
  • the dinitrobenzoate is reduced to n-octadecyl 3,5-diaminobenzoate using hydrazine as a reducing agent.
  • the value of x in formula II may be varied.
  • Diamines of the present invention may be purified by chromatography on deactivated silica gel and subsequent recrystalization. Purified diamines may then be contacted with acid dianhydrides to produce polyimides.
  • the synthesis of polyimides is known in the art. See for example, “Synthesis and Characterization of Aromatic Polyesters and Polyimides Containing Mesogenic Pendent Groups," PhD dissertation of Shyh-Yeu Wang, The University of Akron, December, 1995, the disclosure of which is herein incorporated by reference. Briefly summarized, UA387 12 polyimide precursors may be synthesized from dianhydrides and diamines by either a 2-step or a 1-step method.
  • a soluble polyimide precursor i.e., a polyamic acid
  • the polyimide precursor is cyclodehydrated to form the corresponding polyimide either by thermal or chemical methods.
  • the 2-step method gives high molecular weight polyimides if the diamine is highly reactive. However, when the diamine contains electron withdrawing groups such as CF3, CN and NO2, for example, the reactivity of the diamine is reduced and low molecular weight products result. When such electron withdrawing groups are present, the 1-step method is preferred.
  • polymerization is carried out by heating the dianhydride and diamine at 180°-220°C in high boiling solvents, such as m-cresol and p-chlorophenol for example, in the presence of a tertiary amine catalyst. Under these conditions, polymerization and imidization occur essentially simultaneously. The water generated from imidization is continuously removed, such as by distillation for example.
  • solvents such as m-cresol and p-chlorophenol for example
  • the polyimide alignment layer of the present invention provides a high pre-tilt angle.
  • the alignment layer provides a pre-tilt angle between about 5° and about 90°.
  • the alignment layer provides a pre-tilt angle between about 10° and about 80°.
  • the polyimide layer provides a pre-tilt angle between about 20° and about 80°.
  • the polyimide layer provides a pre-tilt angle between about 40° and about 70°. It will be appreciated that the pre-tilt angle described herein relates to the use of one single alignment layer with one single liquid crystal layer and not a plurality of layers to obtain the necessary or desired angle. A greater thickness of liquid crystal material is not required.
  • 2,3,6,7,10,11 hexa[4-(6- acryloyloxy-n-hexyloxy)benzo]triphenylene, a discotic liquid crystal material of the present invention may be synthesized by the following method.
  • 4- (6- hydroxyhexyloxyl) benzoic acid is synthesized by alkylating a commercially available ethyl 4-hydroxybenzoic ester with 6-chlorohexanol.
  • Other halogenated alcohols may also be used in place of the 6-chlorohexanol to produce other discotic liquid crystal materials.
  • the resulting intermediate is then hydrolyzed to generate a hydroxyl-terminated benzoic acid, which is treated with acryloyl chloride in dioxane in the presence of N,N-dimethylaniline to generate 4-(6-hydroxyhexyloxyl) benzoic acid.
  • the 4-(6-hydroxyhexyloxyl) benzoic acid is then placed in THF and pyridine. The mixture is cooled to 0° and acryloyl chloride is added dropwise. Other acid chlorides may also be substituted for acryloyl chloride to produce other discotic liquid crystal compounds. The mixture is then stirred overnight and the solid product is removed by filtration.
  • the filtrate is then poured into water and the resulting precipitate is collected by filtration and washed with water.
  • the 4- (6- acryloyloxy)hexyloxyl benzoic acid product may then be purified by recrystalization from isopropanol.
  • the 4-(6-acryloyloxy)hexyloxyl benzoic acid is then contacted with 2,3,6,7,10,11 hexahydroxytriphenylene in the presence of 4- (dimethylamino)pyridiniump-toluenesulfonate (DPTS) in acetone under nitrogen.
  • DPTS 4- (dimethylamino)pyridiniump-toluenesulfonate
  • the filtrate is then concentrated under reduced pressure to yield a milky viscous liquid.
  • the 2,3,6,7,10,11 hexa[4-(6-acryloyloxy-n-hexyloxy)benzo]triphenylene product is purified by chromatography on silica gel using acetone/hexane (1:2, v:v) as the eluent.
  • O-plate compensators were produced using high-pretilt polyimide alignment layers, as described below.
  • the photopolymerizable liquid crystal components Cmallx, Cma6x and Ca6x were solution-cast or spin-cast onto alignment substrates. The structures of these liquid crystals are shown below. UA387 14
  • the film thickness was controlled by adjusting the solution concentration and spinning rate. A heat treatment was carried out at a predetermined temperature after the coating had been deposited. The films, which contained UV initiators, were then crosslinked with UV irradiation.
  • the discotic LC molecules of the present invention undergo a crosslinking reaction to form uniaxially negative birefringence films, in which the in-plane refractive index (n(TE)) is different than that of the out-of- plane refractive index (n(TM)).
  • the array of discotic LC molecules is randomly stacked with their normal axis perpendicular to the substrate.
  • surface alignment technology In order to achieve anisotropic orientation of in-plane discotic LC UA387 15 molecules, one must use surface alignment technology to align the discotic LC molecules.
  • the use of rubbed polyimide alignment layers that generate high pretilt angles is one way to achieve an oblique optical axis within negative retardation films.
  • the in-plane optical properties parallel to the rubbing direction may be different from those perpendicular to the rubbing direction. It is also believed that this topological arrangement can be retained after UV crosslinking, and that the oblique optical axis and negative birefringence are stable with respect to the orientation direction.
  • the anisotropic optical birefringence was measured using a Metricon prism coupler method based on different refractive indices of the in-plane n(TE) and out-of-plane n(TM) modes.
  • Table 1 The optical properties of the Cmallx films on a high pretilt angle alignment layer-coated glass substrate are summarized in Table 1.
  • Cmallx films were formed on alignment layers providing a 10° or an 18° pre-tilt angle.
  • the in- plane (n(TE)) and out-of-plane (n(TM)) optical responses of the films relative to the rubbing direction of the alignment layer were tested in duplicate for each direction.
  • the linear optical in-plane (n(TE)) responses along different directions in the films varied.
  • the optical birefringence of the film which is the difference between the out-of-plane refractive index and the in-plane refractive index, is expressed as ⁇ n. In all cases, the films exhibited negative birefringence .
  • the anisotropic optical properties are indicative of films with oblique optical axes.
  • a prototype O-plate compensation film of a Ca6x compound was also constructed on a high pretilt (39°) alignment substrate using solution casting.
  • the in-plane (n(TE)) and out-of-plane (n(TM)) optical responses of the films relative to the rubbing direction of the alignment layer were tested in duplicate for each direction, as described above.
  • the observed properties of the films at a thickness of 20 micrometers are summarized in Table 2.
  • the optical birefringence ( ⁇ n) and retardation values ( ⁇ n x the thickness of the film) are larger than those along the other directions.
  • the out-of-plane refractive index n(TM) is very similar along the different orientation directions.
  • optical retardation values are between about 80 and about 240 nm, which is useful for optical applications. Additionally, after UV irradiation, an oblique optical axis could be seen by the naked-eye when viewing along the rubbing direction with respect to the substrate. UA387 17
  • a prototype photo-polymerizable liquid crystal film was made using a high pretilt polyimide alignment layer to achieve the O-plate with Ca6x.
  • the photopolymerizable LC compounds were spin-cast onto the polyimide alignment substrate with a pretilt angle of 39° and the thickness was controlled to approximately 4 ⁇ m.
  • a heat treatment at a preset temperature of 100°C was carried out after the coating had been applied.
  • the photopolymerizable LC films are generated by UV irradiation after the thermal treatment.
  • the resulting film optical properties were observed as described above and are listed in Table 3.
  • the optical data for commercially available (Fuji) retardation films are listed in Table 4 for comparison.
  • the Ca6x discotic LC molecules are believed to undergo a crosslinking reaction to form uniaxially negative birefringence films, in which the in-plane refractive index (n(TE)) is larger than that of the out-of-plane refractive index (n(TM)).
  • the optical birefringence parallel to the rubbing direction is larger than that perpendicular to the rubbing direction.
  • the desired retardation values of the optical films ranged from about 100 nm to about 400 nm.
  • Untreated films of Ca6x are semi-solid at room temperature. They also show haziness when crosslinked at room temperature, which is believed to be caused by UA387 18 a highly ordered columnar or other ordered phase. However, at elevated temperature, the compound's viscosity is relatively low before UV curing. Thus, it can easily be oriented on alignment layers. Therefore, in some applications, it may be desirable to treat the films at about 100°C for 15 minutes, for example, and then photo-crosslink the LC compounds at that temperature to avoid the higher ordered phase structures.
  • the results indicate that the linear optical in-plane responses of the films along the different directions with respect to the rubbing direction are anisotropic, which is the first sign of a negative birefringent film with an oblique optical axis.
  • the optical birefringence is approximately 0.037-0.040 perpendicular to the rubbing direction, while the optical birefringence is 0.0612- 0.0635 in the direction parallel to the rubbing direction.
  • These optical birefringence results on the alignment surface are obviously larger than those data without alignment substrates. This indicates that both the orientation along the out-of-plane and in-plane direction can be improved on the alignment layer substrates. Thus it is believed that the molecular packing arrangement of discotic LC molecules becomes more ordered in both of the directions.
  • the optical retardation values are between 0.0440 and 0.0458 perpendicular to the rubbing direction, and the retardation values are between 0.0617 and 0.0622 parallel to the rubbing direction (see Table 4) . Therefore, the optical birefringence and retardation values parallel to the rubbing direction are greater that those perpendicular to the rubbing direction. However, the out-of-plane refractive index is almost constant along the different orientation directions.
  • the optical retardation values range from 150 nm perpendicular to the rubbing direction to 250 nm parallel to the rubbing direction. After UV irradiation, an oblique optical axis can be directly observed by the naked- eye from different angles, which correspond to different directions with respect to the rubbing direction.
  • the Cma6x crosslinkable compound is a highly desirable compound for use in O-plate compensators because it displays a nematic phase at room temperature with a low viscosity.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Polarising Elements (AREA)
  • Liquid Crystal (AREA)

Abstract

Cette invention concerne un composé à cristaux liquides discotiques photopolymérisables. Ledit composé peut être utilisé comme composant d'un compensateur optique pour affichage à cristaux liquides tel qu'un compensateur à plaque O. Est également décrite un procédé de fabrication d'un composé à cristaux liquides discotiques.
PCT/US2002/000059 2001-01-02 2002-01-02 Materiaux pour cristaux liquides discotiques et films de compensation a plaque o realises a partir desdits materiaux WO2002054141A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2002239812A AU2002239812A1 (en) 2001-01-02 2002-01-02 Discotic liquid crystal materials and o-plate compensation films made therefrom

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US25916201P 2001-01-02 2001-01-02
US60/259,162 2001-01-02

Publications (2)

Publication Number Publication Date
WO2002054141A2 true WO2002054141A2 (fr) 2002-07-11
WO2002054141A3 WO2002054141A3 (fr) 2002-10-10

Family

ID=22983777

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2002/000059 WO2002054141A2 (fr) 2001-01-02 2002-01-02 Materiaux pour cristaux liquides discotiques et films de compensation a plaque o realises a partir desdits materiaux

Country Status (2)

Country Link
AU (1) AU2002239812A1 (fr)
WO (1) WO2002054141A2 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20180085841A (ko) * 2017-01-19 2018-07-30 한국화학연구원 디스코틱(discotic) 액정 화합물을 포함하는 방열용 조성물, 이로부터 제조된 방열필름 및 이의 제조방법

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5635105A (en) * 1994-05-13 1997-06-03 Fuji Photo Film Co., Ltd. Liquid crystal display and optical compensatory sheet and process for preparation of the same
US5693379A (en) * 1994-10-20 1997-12-02 Chisso Corporation Polyimide
US5747121A (en) * 1995-02-08 1998-05-05 Fuji Photo Film Co., Ltd. Optical compensatory sheet

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5635105A (en) * 1994-05-13 1997-06-03 Fuji Photo Film Co., Ltd. Liquid crystal display and optical compensatory sheet and process for preparation of the same
US5693379A (en) * 1994-10-20 1997-12-02 Chisso Corporation Polyimide
US5747121A (en) * 1995-02-08 1998-05-05 Fuji Photo Film Co., Ltd. Optical compensatory sheet

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DATABASE CAPLUS [Online] GE, J.J.: 'Surface studies of polyimide thin film via surface-enhanced raman scattering and second harmonic generation', XP002950906 Database accession no. 1998:807158 & MACROMOLECULAR RAPID COMM. vol. 19, no. 12, 1998, pages 619 - 623 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20180085841A (ko) * 2017-01-19 2018-07-30 한국화학연구원 디스코틱(discotic) 액정 화합물을 포함하는 방열용 조성물, 이로부터 제조된 방열필름 및 이의 제조방법
KR101893872B1 (ko) * 2017-01-19 2018-09-03 한국화학연구원 디스코틱(discotic) 액정 화합물을 포함하는 방열용 조성물, 이로부터 제조된 방열필름 및 이의 제조방법

Also Published As

Publication number Publication date
AU2002239812A1 (en) 2002-07-16
WO2002054141A3 (fr) 2002-10-10

Similar Documents

Publication Publication Date Title
KR100326615B1 (ko) 액정성고분자필름,그의제조방법및이용
JP4592005B2 (ja) 偏光素子、液晶パネル、液晶テレビおよび液晶表示装置、ならびに偏光素子の製造方法
EP2143710B1 (fr) Compose de cristaux liquides polymerisables, composition de cristaux liquides polymerisables, polymere cristallin liquide et materiau anisotropique sur le plan optique
US6805920B2 (en) Polymerizable liquid crystal compound and optical film
JP5360212B2 (ja) 光反応性基を有する液晶性ポリイミドよりなる位相差膜を有する液晶表示装置
US20140009732A1 (en) Liquid crystal display and method of manufacturing the same
KR102533309B1 (ko) 액정 층에서 프리-틸트각의 안정화를 위한 신규의 광배향 조성물
EP0940707A1 (fr) Film retardateur optique
JP2016004142A (ja) 光学フィルム積層体とその製造方法及び該積層体を含む液晶表示パネル
KR20120055554A (ko) 광학 디바이스 또는 전기광학 디바이스용 에스테르 그룹 함유 액정
KR100624750B1 (ko) 액정표시장치 및 그의 구동방법
JP5401823B2 (ja) 重合性液晶化合物、重合性液晶組成物、液晶性高分子および光学異方体
KR101756563B1 (ko) 중합성 액정 화합물, 액정 조성물, 고분자 재료와 그 제조 방법 및 필름
JP5407870B2 (ja) 重合性液晶化合物、重合性液晶組成物、液晶性高分子および光学異方体
JP7523281B2 (ja) 重合体、重合性液晶組成物、光学異方性膜、光学フィルム、偏光板および画像表示装置
US5491001A (en) Method for producing viewing angle compensator for liquid crystal display
CN113348388B (zh) 光学膜层积体和正c板以及光学膜层积体的制造方法
JP2002268068A (ja) 液晶配向膜、棒状液晶性分子を配向させる方法、光学補償シートおよび偏光板
US6088077A (en) Temperature matched retardation layer
US20040138408A1 (en) Polymide lcd alignment layer
WO2002054140A2 (fr) Couches de polymide d'alignement pour affichage a cristaux liquides
WO2002054141A2 (fr) Materiaux pour cristaux liquides discotiques et films de compensation a plaque o realises a partir desdits materiaux
JP3399705B2 (ja) 液晶表示素子用補償フィルムおよび該補償フィルムを組み込んだ液晶表示装置
JP6824941B2 (ja) 光学フィルム積層体とその製造方法及び該積層体を含む液晶表示パネル
JPH11119211A (ja) 光学異方素子

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A2

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ OM PH PL PT RO RU SD SE SG SI SK SL TJ TM TN TR TT TZ UA UG US UZ VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A2

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

AK Designated states

Kind code of ref document: A3

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ OM PH PL PT RO RU SD SE SG SI SK SL TJ TM TN TR TT TZ UA UG US UZ VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A3

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase in:

Ref country code: JP

WWW Wipo information: withdrawn in national office

Country of ref document: JP