WO2001009674A1 - Affichage a cristaux liquides nematiques torsades en mode normalement noir - Google Patents

Affichage a cristaux liquides nematiques torsades en mode normalement noir Download PDF

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Publication number
WO2001009674A1
WO2001009674A1 PCT/JP2000/005132 JP0005132W WO0109674A1 WO 2001009674 A1 WO2001009674 A1 WO 2001009674A1 JP 0005132 W JP0005132 W JP 0005132W WO 0109674 A1 WO0109674 A1 WO 0109674A1
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WIPO (PCT)
Prior art keywords
liquid crystal
film
optical compensation
twisted nematic
crystal display
Prior art date
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PCT/JP2000/005132
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English (en)
Japanese (ja)
Inventor
Takehiro Toyooka
Original Assignee
Nippon Mitsubishi Oil Corporation
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
Priority claimed from JP11217841A external-priority patent/JP2001042323A/ja
Priority claimed from JP11217842A external-priority patent/JP2001042325A/ja
Priority claimed from JP11217843A external-priority patent/JP2001042122A/ja
Priority claimed from JP11228204A external-priority patent/JP2001051274A/ja
Priority claimed from JP11228205A external-priority patent/JP2001051118A/ja
Priority claimed from JP11228206A external-priority patent/JP2001051273A/ja
Priority claimed from JP37134099A external-priority patent/JP2001188231A/ja
Priority claimed from JP37134199A external-priority patent/JP2001188225A/ja
Application filed by Nippon Mitsubishi Oil Corporation filed Critical Nippon Mitsubishi Oil Corporation
Publication of WO2001009674A1 publication Critical patent/WO2001009674A1/fr

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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G02F1/133633—Birefringent elements, e.g. for optical compensation using mesogenic materials
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/137—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
    • G02F1/139—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent
    • G02F1/1396—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent the liquid crystal being selectively controlled between a twisted state and a non-twisted state, e.g. TN-LC cell
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2413/00—Indexing scheme related to G02F1/13363, i.e. to birefringent elements, e.g. for optical compensation, characterised by the number, position, orientation or value of the compensation plates
    • G02F2413/02—Number of plates being 2
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2413/00—Indexing scheme related to G02F1/13363, i.e. to birefringent elements, e.g. for optical compensation, characterised by the number, position, orientation or value of the compensation plates
    • G02F2413/15—Indexing scheme related to G02F1/13363, i.e. to birefringent elements, e.g. for optical compensation, characterised by the number, position, orientation or value of the compensation plates with twisted orientation, e.g. comprising helically oriented LC-molecules or a plurality of twisted birefringent sublayers

Definitions

  • the present invention relates to a normally black mode TN liquid crystal element having improved display contrast, gradation characteristics, and viewing angle characteristics of display colors, that is, a normally black mode twisted nematic liquid crystal display element.
  • TN-LCD Actively driven, nematic liquid crystal display devices
  • MIM elements MIM elements
  • a normally black mode type TN-LCD (hereinafter abbreviated as NB-TN-LCD), in which a black display is made when no voltage is applied and the liquid crystal alignment state in the cell at the time of black display forms a twisted structure.
  • NW-TN-LCD normally-white TN-LCD
  • NW-TN-LCD normally-white TN-LCD
  • NB_TN-LCD has a twisted liquid crystal alignment state in the cell during black display, it cannot completely block light over the entire visible region, and the black display is colored.
  • the present invention provides an optical compensation film exhibiting an excellent color compensation effect not only when incorporated into an NB-TN_LCD but also when incorporated into other liquid crystal display elements, and is provided with the optical compensation film.
  • An optical compensator comprising a combination of a film and a film exhibiting optically negative anisotropy.
  • the present invention also provides an NB-TN-LCD incorporating an optical compensation film exhibiting an excellent color compensation effect or an optical auxiliary element comprising a combination of this film and a film exhibiting optically negative anisotropy. provide.
  • the optical compensation film according to the present invention is characterized in that it has a liquid crystal layer maintaining twisted nematic orientation, and that the twist angle of orientation and the film thickness are substantially proportional.
  • An optical compensatory element has an optical compensatory film having a liquid crystal layer maintaining twisted nematic alignment, wherein the twist angle of the alignment and the film thickness are substantially proportional, and birefringence in the film thickness direction.
  • Index reffractive index anisotropy
  • One of the NB-TN-LCDs proposed by the present invention has a driving liquid crystal cell having a nematic liquid crystal layer between two polarizing plates, and has a twisted nematic alignment.
  • An optical compensation film having a liquid crystal layer, wherein the product ( ⁇ nd) of the refractive index anisotropy ⁇ n of the nematic liquid crystal layer and the thickness d of the liquid crystal layer is 200 nm to 600 nm.
  • the nematic liquid crystal layer has a twist angle in a twist orientation of 80 ° to 100 °, and the refractive index anisotropy ⁇ of the optical compensation film and the thickness d J of the liquid crystal layer.
  • the absolute value of the product ( ⁇ n, dt) in the film plane is approximately equal to the above ⁇ nd, and the twist direction of the twisted nematic orientation of the optical compensation film is the same as the twist direction of the nematic liquid crystal layer. In the opposite direction, the average absolute value of the twist angle of the twisted nematic orientation in the optical compensation film is substantially equal to the absolute value of the twist angle of the nematic liquid crystal layer.
  • Another one of the present invention is to propose NB TN- L CD was the NB TN- in L CD, the thickness direction of the product of the birefringence delta eta 2 and the thickness d 2 (A n 2 d 2) was, - a 2 0 nm to one 3 0 0 nm optically film showed a negative anisotropy in the range of, between the polarizing plate and the driving liquid crystal cell, additionally interposed It is characterized by having.
  • the above-mentioned optical compensation film used in the NB-TN_LCD of the present invention is more preferably such that the twist angle of twisted nematic orientation and the film thickness are in a substantially proportional relationship.
  • FIG. 1 is a sectional view showing a configuration of an example of a liquid crystal display device according to the present invention.
  • FIG. 2 is a graph showing the contrast ratio of the liquid crystal display devices of Example 2 and Reference Example 2.
  • FIG. 3 is a sectional view showing the configuration of another example of the liquid crystal display device according to the present invention.
  • FIG. 4 is a graph showing the contrast ratio of the liquid crystal display devices of Example 4 and Reference Example 3.
  • FIG. 5 is a graph showing left-right viewing angle gradation characteristics of the liquid crystal display element of Example 4.
  • FIG. 6 is a graph showing the left-right viewing angle gradation characteristics of the liquid crystal device of Reference Example 3.
  • FIG. 7 is a graph showing the contrast ratio of the liquid crystal display devices of Example 6 and Reference Example 5.
  • FIG. 8 shows the contrast ratio of the liquid crystal display devices of Example 9 and Reference Example 6. This is a graph.
  • FIG. 9 is a graph showing left-right viewing angle gradation characteristics of the liquid crystal display element of Example 11;
  • FIG. 10 is a graph showing left-right viewing angle gradation characteristics of the liquid crystal display element of Example 12.
  • FIG. 11 is a sectional view showing the configuration of still another example of the liquid crystal display device according to the present invention.
  • FIG. 12 is a graph showing left-right viewing angle gradation characteristics of the liquid crystal display element of Example 13;
  • FIG. 13 is a graph showing the left-right viewing angle gradation characteristics of the liquid crystal display element of Reference Example 7.
  • FIG. 14 is a cross-sectional view illustrating a configuration of a liquid crystal display element of Comparative Example 1.
  • FIG. 15 is a graph showing the left-right viewing angle gradation characteristics of the liquid crystal display element of Comparative Example 1.
  • FIG. 16 is a graph showing the left-right viewing angle gradation characteristics of the liquid crystal display element of Example 15;
  • FIG. 17 is a graph showing left-right viewing angle gradation characteristics of the liquid product display element of Example 16;
  • FIG. 18 is a graph showing left-right viewing angle gradation characteristics of the liquid crystal display element of Example 17;
  • FIG. 19 is a graph showing the left-right viewing angle gradation characteristics of the liquid crystal display element of Reference Example 8.
  • FIG. 20 is a graph showing the left-right viewing angle gradation characteristics of the liquid crystal display element of Comparative Example 2.
  • One of the optical compensation films proposed by the present invention is a twisted nematic liquid crystal film exhibiting an excellent color compensation effect not only when incorporated into an NB-TN-LCD but also when incorporated into other liquid crystal display devices.
  • this is referred to as a general-purpose optical compensation film.
  • the feature is that the twist angle of twisted nematic orientation is substantially proportional to the film thickness.
  • the torsion angle of the orientation and the film thickness are in a substantially proportional relationship means that the thickness of one film is not uniform, the torsion angle is large at a place where the film thickness is large, and the torsion angle is at a place where the film thickness is thin. Small and small This means that the torsion angle increases or decreases in proportion to the increase or decrease in the lum thickness.
  • the variation of the film thickness of the optical compensation film is within 20% of the average film thickness, preferably within ⁇ 10%, more preferably within ⁇ 5%.
  • the degree of twisting of the liquid crystal molecules in the liquid crystal film formed between the alignment substrates depends on the alignment regulating force applied to the alignment substrates. It is dominated, and even if the distance between the alignment substrates, in other words, the thickness of the liquid crystal film changes, the twist angle of the alignment does not change.
  • the optical compensation film in a broad sense referred to in the present invention changes the twist angle of liquid crystal molecules in proportion to the change in the film thickness.
  • Another one of the optical compensation films proposed by the present invention is a twisted nematic liquid crystal film which exhibits a particularly excellent color compensation effect when incorporated in an NB_TN-LCD.
  • the average absolute value of the twist angle of the twisted nematic alignment in the liquid crystal film is substantially equal to the absolute value of the twist angle of the nematic liquid crystal layer.
  • the optical compensation film for NB-TN-LCD of the present invention that satisfies the above three requirements does not need to maintain the relationship that the twist angle of the twisted nematic orientation is substantially proportional to the film thickness of the film.
  • the twist angle of the twisted nematic orientation is preferably substantially proportional to the film thickness of the film.
  • the optical compensation film of the present invention has a film-forming ability and retains a twisted nematic liquid crystal phase irrespective of whether it is for general use or for NB-TN-LCD. It is prepared from a liquid crystal material that can be used.
  • the liquid crystal material preferably has optically positive uniaxiality, but may have negative uniaxiality.
  • the liquid crystal material used for preparing the optical compensation film of the present invention is roughly classified into a liquid crystal material mainly composed of a high-molecular liquid crystal and a liquid crystal material mainly composed of a low-molecular liquid crystal.
  • Liquid crystal material mainly composed of polymer liquid crystal
  • the polymer liquid crystal which is the main component of this liquid crystal material, can generate a twisted nematic liquid crystal phase when heated to a temperature equal to or higher than the glass transition temperature Tg.
  • the orientation must be glass-fixed.
  • the polymer liquid crystal used in the present invention preferably does not have a higher-order liquid crystal phase such as a smectic phase or a crystal phase in a lower temperature region than the twisted nematic liquid crystal phase.
  • the T g of the polymer liquid crystal is in the range of 40 ° C. to 180 ° C., preferably in the range of 50 ° C. to 150 ° C., and more preferably in the range of 60 ° C. to 120 ° C. It is desirable to be within the range.
  • the molecular weight of the polymer liquid crystal is determined by measuring the temperature of a polymer liquid crystal solution having a concentration of 0.5% by mass prepared using a phenol / tetrachloroethane mixed solvent (weight ratio: 60/40) at a temperature of 25 ° C. It is desirable that the molecular weight be such that the logarithmic viscosity measured in C is in the range of 0.05 to 3.0, preferably in the range of 0.77 to 2.0. If the molecular weight is too high, it is difficult for the liquid crystal molecules to undergo twisted nematic alignment, and if the molecular weight is too low, the mechanical strength of the finally obtained film is reduced.
  • a liquid crystal material containing a polymer liquid crystal as a main component must contain a component having an optically active group that induces twisted nematic alignment. Therefore, when the polymer liquid crystal itself does not contain an optically active group, a substance containing the optically active group is used in combination with the polymer liquid crystal.
  • the substance containing an optically active group is compatible with the polymer liquid crystal, and it does not matter whether the substance itself exhibits liquid crystallinity as long as it does not impair the twisted nematic alignment formed by the polymer liquid crystal.
  • the amount of the optically active group contained in the liquid crystal material is contained in the polymer liquid crystal, the amount is usually 0.01 to 40 mol% based on the total number of moles of the constituent units of the polymer liquid crystal. Preferably it is in the range of 0.1 to 30 mol%, more preferably 0.2 to 20 mol%, most preferably 0.4 to 10 mol%.
  • the substance containing the optically active group is usually added to the liquid crystal material at a concentration of 0.0. It is mixed in the range of 1 to 50% by weight, preferably 0.05 to 40% by weight, more preferably 0.1 to 30% by weight, and most preferably 0.2 to 20% by weight.
  • the amount of the optically active group contained in the liquid crystal material is smaller than the above lower limit, the nematic liquid crystal formed by the liquid crystal material may not be sufficiently twisted. The torsion may be excessive.
  • a cross-linking agent such as a bis azide compound ⁇ ⁇ glycidyl methacrylate is added in an amount that does not hinder the development of the twisted nematic phase. Heat resistance can be improved.
  • various additives such as dichroic dyes, dyes, pigments, antioxidants, ultraviolet absorbers, and hard coat agents are appropriately added to the liquid crystal material containing a polymer liquid crystal as a main component, as necessary. You can also.
  • Polymer liquid crystals which are the main components of liquid crystal materials, include main-chain liquid crystal polymers such as polyester, polyamide, polycarbonate, and polyesterimide, or polyacrylates, polymethacrylates, polymeronates, and polysiloxanes. Both side chain type liquid crystal polymers can be used. Among them, a liquid crystalline polyester, which has good orientation in forming a twisted nematic alignment and is relatively easy to synthesize, is desirable, and a liquid crystalline polyester in which the polymer constituent unit contains an optically active group is particularly desirable.
  • the constituent units of the polymer include aromatic or aliphatic diol units, aromatic or aliphatic dicarboxylic acid units, and aromatic or aliphatic hydroxycarboxylic acid units.
  • Liquid crystal material mainly composed of low molecular liquid crystal
  • the low-molecular liquid crystal which is a main component of the liquid crystal material, must be capable of generating a twisted nematic liquid crystal phase at an appropriate temperature and capable of fixing the liquid crystal phase by a photocuring reaction.
  • low-molecular liquid crystals do not contain optically active groups that induce twisted nematic alignment. Therefore, a substance containing an optically active group is used in combination with a liquid crystal material mainly composed of a low-molecular liquid crystal.
  • the substance having an optically active group has compatibility with the low-molecular liquid crystal, and it does not matter whether the substance itself exhibits liquid crystal properties as long as the low-molecular liquid crystal does not impair the twisted nematic alignment.
  • the amount of the substance having an optically active group is 0.01 to 40%, preferably 1 to 30%, more preferably 0 to 10% of the number of moles of the low-molecular liquid crystal as the number of moles of the optically active group. .
  • the liquid crystal material mainly composed of a low molecular liquid crystal must also contain a component having a polymerizable group that is polymerized and cured by light irradiation. Therefore, if the low-molecular liquid crystal itself is not photocurable, photopolymerizable groups that polymerize upon irradiation with light, such as acrylic, methyl, vinyl, aryl, epoxy, and fluoromid groups A photopolymerizable compound having a cinnamoyl group is used in combination with a low-molecular liquid crystal.
  • the amount of photopolymerizable groups that must be contained in the liquid crystal material regardless of whether it is derived from a photocurable low-molecular liquid crystal or a non-liquid crystalline photopolymerizable compound,
  • the polymerizable group equivalent is selected in the range of usually 0.05 to 20 millimol, preferably 0.01 to 5 millimol, more preferably 0.1 to 3 millimol. If the amount is less than 0.05 millimoles, the twisted nematic alignment formed by the low-molecular liquid crystal may not be fixed by light irradiation.If the amount is more than 20 millimoles, the storage stability of the liquid crystal material is low. May drop.
  • a photoreaction initiator can be added to the liquid crystal material containing low-molecular liquid crystal as a main component, if necessary.
  • the addition amount is selected in the range of 0.01 to 20% by weight, preferably 0.1 to 10% by weight, more preferably 0.5 to 5% by weight of the low-molecular liquid crystal occupying the liquid crystal material. .
  • photoreaction initiators include various derivatives such as benzyl, benzoin ether, Michler's ketone, anthraquinone, acetate phenone, ben V phenone, bimidazole, triazine, thioxanthone, and acylphosphine oxide.
  • One or more of salts, triarylsulfonium salts, sulfonic esters and the like can be used.
  • a sensitizer can be added as long as the liquid crystallinity of the low-molecular liquid crystal is not impaired.
  • a desired twisted state can be obtained by irradiating EB (electron beam) without using a photoreaction initiator or the like at all.
  • Donema Tic orientation can also be fixed.
  • a liquid crystal material containing a low molecular liquid crystal as a main component may be, for example, a bisazide compound.
  • a crosslinking agent such as glycidyl methacrylate can be added in an amount that does not prevent the development of the twisted nematic phase.
  • various additives such as dichroic dyes, dyes, pigments, antioxidants, ultraviolet absorbers, hard coat agents and the like can be appropriately added.
  • any low-molecular liquid crystal having a basic skeleton of a biphenyl derivative, a phenylbenzene derivative, a stilbene derivative, or the like can be used. Is preferable. Low-molecular liquid crystals can be used irrespective of whether they are photo-curable or not, even if they are lyotropic or thermotropic. Is preferably a low-molecular liquid crystal.
  • a solution of the liquid crystal material is prepared, and one alignment is performed. It is preferable to employ a method of applying this solution to the surface of the substrate having the alignment regulating force.
  • the solvent for the liquid crystal material varies depending on the type of liquid crystal material to be dissolved therein, but usually, hydrocarbons such as toluene, xylene, butylbenzene, tetrahydrodronaphthene and decahydronaphthalene, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether Propylene glycol dimethyl ether, ethers such as tetrahydrofuran, ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, ethyl acetate, butyl acetate, ethylene glycol monomethyl ether acetate, propylene Ester type such as glycol monomethyl ether acetate, ethyl lactate, arptyrolactone, N-methyl-2-pyro Amides such as ridone, dimethylformamide, and dimethylacetamide; halogenated hydrocarbons such as dichloromethane, carbon t
  • the concentration of the prepared solution depends on the solubility of the solute liquid crystal material and the thickness of the optical compensation film to be manufactured. %, Preferably 3 to 40% by weight, more preferably 7 to 30% by weight.
  • Surfactants can be added to the liquid crystal material solution to facilitate application.
  • surfactants examples include cationic surfactants such as imidazoline, quaternary ammonium salts, alkylamine oxides, and polyamine derivatives; polyoxyethylene-polyoxypropylene condensates; Or secondary alcohol ethoxylate, alkylphenol ethoxylate, polyethylene glycol and its ester, sodium lauryl sulfate, ammonium lauryl sulfate, lauryl sulfate amines, alkyl-substituted aromatic sulfonate, alkyl phosphate, aliphatic or Anionic surfactants such as aromatic sulfonic acid formalin condensates; amphoteric surfactants such as lauryl amide propyl betaine and lauryl amino acetate betaine; polyethylene glycol fatty acid esters; polyoxyethylene alkyl Nonionic surfactants such as amines, perfluoroalkylsulfonates, perfluoroalkylcarboxy
  • the amount of the surfactant to be added depends on the type of the surfactant, the solvent, and the orientation substrate to be coated, but is usually from 10 ppm to 10%, preferably from 50 ppm to the weight of the liquid crystal material. It is in the range of 5%, more preferably 0.01% to 1%.
  • roll coating die coating, vacuum coating, gravure roll coating, spray coating, dip coating, spin coating, etc. may be used to apply the liquid crystal material solution to the alignment substrate. It can. Board for rooster
  • the alignment substrate on which the coating of the liquid crystal material is provided is one that can define the direction of the liquid crystal molecules at the substrate interface. Otherwise, there is a possibility that a desired swisted-donematic alignment cannot be obtained. .
  • orientation substrates examples include polyimide, polyamide, polyimide, polyetherimide, polyetheretherketone, polyetherketone, polyketonesulfide, polyethersulfone, polysulfone, polyphenylenesulfide, and polyphenylene.
  • an alignment film such as a rubbing plastic alignment substrate in which one surface of the above-mentioned plastic substrate has been subjected to a rubbing treatment in advance
  • a rubbing-treated plastic film for example, a rubbing polyimide film, a rubbing polyvinyl alcohol film, and the like
  • an oriented substrate laminated on a plate an oriented substrate provided with an obliquely deposited silicon oxide film, and the like.
  • a triacetylcellulose film as an oriented substrate because it can be used as a film exhibiting optically negative anisotropy in an optical compensator described later.
  • the triacetyl cell mouth film has a high alignment ability, so it can be used as an alignment substrate without any surface treatment, etc.Rubbing treatment, oxidation treatment, corona discharge treatment, UV-ozone treatment, etc. A surface treatment can be applied to the alignment substrate. Further, an alignment film such as polyimide-polyvinyl alcohol may be formed on the triacetyl cellulose film to form an alignment substrate.
  • the adhesive strength between the film and the alignment film may be reduced.
  • Mechanical strength associated with the problem can be solved by means of providing an easily adhesive layer such as a gelatin layer between the triacetyl cellulose film and the alignment film.
  • the coating film of the liquid crystal material solution formed on the alignment substrate is then dried in order to remove the solvent until the fluidity is lost. Drying can be natural drying at room temperature, forced drying using an appropriate heating means, or deviation.
  • the coating film After removing the solvent, the coating film is subjected to a process of forming a twisted nematic phase in the liquid crystal material forming the coating film and a process of fixing the formed liquid crystal phase.
  • the coating film is usually at 50 ° C to 3 ° C, preferably at 100 ° C to 260 ° C.
  • a heat treatment in a temperature range of ° C for 10 seconds to 2 hours, preferably for 20 seconds to 1 hour, a twisted nematic phase is developed in the coating film.
  • the heat treatment conditions of the coating film, especially the heat treatment temperature are adjusted in consideration of the properties of the polymer liquid crystal contained in the coating film. In general, the twist angle of liquid crystal molecules in twisted nematic alignment depends on the concentration of the component having an optically active group contained in the liquid crystal material forming the coating film.
  • the twist angle of the twisted nematic orientation may depend on the heat treatment conditions. Therefore, it is preferable to adjust the heat treatment conditions of the coating film, especially the heat treatment temperature, in consideration of the properties of the polymer liquid crystal contained in the coating film. For example, to obtain the desired'isutetsu Donema tic orientation, force is necessary to employ a relatively low temperature in the heat treatment temperature of the coating film s, than adopted its temperature polymer such as requiring a long time for heat treatment If the liquid crystal is the main component of the coating film, the coating film is heat treated once at high temperature to obtain a monodomain alignment, and then the coating film is stepwise until a desired twist angle is generated in twisted nematic alignment. Alternatively, a method of continuously slow cooling is effective.
  • the heat treatment temperature of the coating film is preferably equal to or higher than the Tg of the polymer liquid crystal contained in the coating film.
  • Heat treatment of the coating can be performed under the influence of an external field such as a magnetic or electric field.
  • the twisted nematic alignment formed by the polymer liquid crystal in the coating film The glass is fixed by cooling the coating film to a temperature below the liquid crystal transition point.
  • nematic alignment in a liquid crystal state may be broken by cooling.
  • a polymer liquid crystal that has no smectic phase or crystalline phase at a temperature lower than the temperature range showing the nematic phase, or has a crystalline phase or smectic phase, but does not exhibit the phase when cooled, If it is selected as the main component of the liquid crystal material, it is possible to completely fix the monodomain twisted nematic alignment to the glass without causing the alignment breakdown due to the phase transition from the smectic phase to the crystal phase during the glass fixing.
  • the cooling temperature for fixing the glass can be arbitrarily selected as long as it is lower than the liquid crystal transition point. For example, by cooling to a temperature lower by 10 ° C. than the liquid crystal transition point, uniform twisted nematic alignment can be fixed to glass.
  • the cooling method is not particularly limited, and the glass fixation can be completed simply by transferring the coating film, which was in the heating atmosphere during the heat treatment, to an atmosphere below the liquid crystal transition point, for example, to a room temperature atmosphere.
  • forced cooling such as air cooling or water cooling can be adopted.
  • the obtained twist angle may vary slightly depending on the cooling rate. Therefore, it is desirable to appropriately adjust the cooling conditions according to the polymer liquid crystal contained in the coating film.
  • the coating film is usually at 20 ° C to 220 ° C, preferably at 50 ° C to 180 °. C, more preferably in a temperature range of 60 ° C. to 160 ° C., within a range of 10 seconds to 2 hours, preferably 10 seconds to 40 minutes, more preferably 20 seconds to 20 minutes.
  • the heat treatment causes the coating to develop a twisted nematic phase.
  • the temperature at which the low-molecular liquid crystal in the coating film is heated to a temperature higher than the temperature range in which the low-molecular liquid crystal exhibits a liquid crystal phase to bring the low-molecular liquid crystal into an isotropic liquid state, and then the temperature at which the liquid crystal phase exhibits
  • a method of forming a twisted nematic orientation in the coating by cooling the coating to range H.
  • twisted nematic alignment can be formed by appropriately changing the temperature within a temperature range in which a liquid crystal phase is exhibited. Specifically, after the low-molecular liquid crystal is roughly aligned on the high temperature side of the temperature range where the nematic phase is exhibited, the temperature is lowered.
  • a method of increasing the degree of order of the liquid crystal alignment by heating, or a method of performing a heat treatment at a temperature exhibiting an isotropic phase and then lowering the temperature to align the liquid crystal in a nematic phase can also be employed.
  • the heat treatment conditions of the coating film are adjusted in the above-mentioned range in consideration of the properties of the low-molecular liquid crystal.
  • a desired twisted nematic alignment is formed in the lyopic pick in the process of removing the solvent from the coating film. Can be omitted.
  • heat treatment of the coating film is useful for achieving perfect orientation.
  • the twisted nematic alignment formed by the low-molecular liquid crystal in the coating film is fixed using a photo-curing reaction by light irradiation.
  • the wavelength of light used for light irradiation is not particularly limited, and electron beams, ultraviolet rays, visible light rays, and infrared rays (heat rays) can be appropriately employed.
  • irradiation light of ultraviolet light or visible light having a wavelength of 150 to 500 nm, preferably 250 to 450 nm, more preferably 300 to 400 nm is used.
  • Light sources include low-pressure mercury lamps (sterilizing lamps, fluorescent chemical lamps, blacklights), high-pressure discharge lamps (high-pressure mercury lamps, metal halide lamps), and short-arc discharge lamps (ultra-high pressure mercury lamps, xenon lamps, mercury xenon lamps) ) Can be used, among which metal-halide damp xenon lamps and high-pressure mercury lamps can be suitably used.
  • the wavelength range of light received by the coating film can be limited.
  • Exposure to the coating depending on the amount of the photopolymerizable and initiator for a low molecular compound contained in the coating film, usually 2 ⁇ 5000mJ / cm 2, preferably 1 0 ⁇ 3 000mJ / cm 2, More preferably, it is selected in the range of 100 to 200 OmJ / cm 2 .
  • Light irradiation is usually performed at a temperature in the range of 0 to 200 ° C, preferably 20 to 180 ° C, and more preferably 25 to 160 ° C. It depends on the properties of the low-molecular liquid crystal contained in the film. For example, a high-order phase such as a smectic phase or a crystalline phase exists in a low-temperature region near room temperature, and a nematic phase exists in a higher temperature region.
  • the twisted nematic alignment formed by a photocurable low-molecular liquid crystal having a crystal phase region is fixed by light irradiation, light irradiation must be performed at a temperature higher than the phase transition point of the higher-order nematic phase. There is. If the twisted nematic phase obtained in the heat treatment process of the coating film is fixed by accidental supercooling of the coating film, a method of re-heating the coating film and irradiating it with light Is adopted.
  • aging can be performed by heat-treating the coating film after light irradiation to eliminate unreacted portions remaining in the coating film.
  • the photocuring reaction does not favor the coexistence of oxygen and ozone, irradiate the coating film with a nitrogen gas atmosphere, or cover the coating film with a film that shields oxygen and ozone.
  • the shielding film include a polyethylene terephthalate film, a polyethylene naphthalate film, a polyphenylene sulfide film, a polyarylate film, a polycarbonate film, a polyvinyl alcohol film, a polyvinyl acetate film, a polyethylene film, a polypropylene film, and a polypropylene film.
  • a vinyl chloride film, a polyvinylidene chloride film, a polyamide film, a polyimide film, a co-extruded polyethylene monoacetate film and the like can be used.
  • the film on the alignment substrate obtained by heat-treating the coating film on the alignment substrate and fixing or twist-fixing the twisted nematic alignment formed by the polymer liquid crystal or low-molecular liquid crystal contained in the coating film on the alignment substrate is as follows. If it is optically isotropic and transparent in the visible light wavelength region, it can be used as it is as the optical compensation film of the present invention without peeling off from the alignment substrate.
  • the alignment substrate is optically anisotropic or opaque in the visible light wavelength range and the optical compensation film has self-supporting properties
  • the alignment substrate is peeled off. be able to.
  • the optical compensation film on the alignment substrate is placed on an optically isotropic and transparent substrate in the visible light wavelength region (hereinafter referred to as a second substrate). (Referred to as a substrate).
  • an adhesive is applied to the surface of the optical compensation film on the alignment substrate and bonded to a second substrate, and after the adhesive is cured, the alignment substrate is Peel off the optical compensation film.
  • Examples of the second substrate include Fujitac (manufactured by Fuji Photo Film Co., Ltd.), Konikatac (manufactured by Konica Corporation), TPX film (manufactured by Mitsui Chemicals, Inc.), A-ton film (manufactured by Nippon Synthetic Rubber Co., Ltd.) Nex film (manufactured by Zeon Corporation of Japan), acrylene film (manufactured by Mitsubishi Rayon Co., Ltd.) and the like can be suitably used, and a glass substrate can be used.
  • the optical compensation film on the alignment substrate can be directly transferred to the glass substrate of the driving liquid crystal cell.
  • the liquid crystal layer can be transferred.
  • the optical compensation film of the present invention is used as a general-purpose optical compensation film, the only requirement of the film is that the twist angle of the twisted nematic orientation held by the film is substantially proportional to the film thickness of the film. It is.
  • the film of the present invention when used as an optical compensation film exclusively for NB_TN-LCD, the film has a refractive index anisotropy ⁇ and a thickness d, of the film, of 3 ⁇ 4 ( ⁇ , d,) and usually 200 ⁇ ! It should be in the range of 600600 nm, preferably 300 nm to 500 nm.
  • the film thickness means the net thickness of the optical compensation film, and does not include the thickness of the second substrate when the film is laminated on a second substrate or the like. ⁇ , d!
  • the twist angle of the twisted nematic orientation fixed in the film is an absolute value. In the range of usually 40 ° to 120 °, preferably 80 ° to 100 °. If the twist angle is out of the above range, the front contrast of the LCD incorporating the film may be reduced.
  • This twist angle can be set to a desired value as appropriate by adjusting the content of the optically active group in the liquid crystal material described above. Further, depending on the type of the optically active group, it can be formed in either a right-handed or left-handed twisted nematic orientation.
  • the direction of the twist angle of the film is set to be opposite to the direction of the twist of the nematic liquid crystal in the driving liquid crystal cell constituting the LCD.
  • the optical compensation film is arranged so that When the optical compensation film of the present invention is used as an optical compensation film exclusively for NB-TN-LCD, the twist angle of the twisted nematic orientation held by the film is substantially proportional to the film thickness of the film. That is not always a requirement.
  • the optical compensatory element of the present invention comprises a combination of the above-described optical compensatory film and a film having optically negative anisotropy.
  • any film which literally exhibits optically negative anisotropy can be used.
  • any film having birefringence ( ⁇ 2 ) in the film thickness direction such as a negative uniaxial film or a negative biaxial film, may be used.
  • the film having optically negative anisotropy used in the optical compensator of the present invention has a product (An 2 d 2 ) of the birefringence An 2 in the film thickness direction and the film thickness d 2 of ⁇ 20. ⁇ -300 nm, preferably in the range of -30 to 250 nm.
  • the optical compensation element composed of a combination of the two films is referred to as NB-TN.
  • NB-TN Incorporated into any of the broader L CDs, including L CDs By doing so, it is possible to exert some optical compensation function.
  • the general-purpose optical compensation film means a film having a twisted nematic orientation and a twist angle of the orientation being substantially proportional to the film thickness of the film. Regardless of the value of ⁇ , d, and the magnitude of the twist angle of the film, it does not matter.
  • the optical compensation film dedicated to TN—LCD retains the twisted nematic orientation, and the values of An, d, are in the range of 200 nm to 600 nm, preferably 300 nm to 500 nm, and the twist angle of the orientation. Means a film in the range of 40 ° to 120 °, preferably 80 ° to 100 °, regardless of whether or not the twist angle of orientation is substantially proportional to the film thickness of the film. .
  • a driving liquid crystal cell having a nematic liquid crystal layer and the above-described optical compensation film are provided between two polarizing plates.
  • the optical compensation film may be arranged on the upper surface side or the lower surface side of the driving liquid crystal cell.
  • the NB-TN-LCD of the present invention may be further provided with a film exhibiting optically negative anisotropy, if necessary. In that case, the film and the optical compensation film can be stacked in any order, and the laminated film can be arranged on the upper surface side or the lower surface side of the driving liquid crystal cell.
  • an optical compensation film is provided on the upper surface (or lower surface) of the driving liquid crystal cell without overlapping the two films, and the film exhibiting optically negative anisotropy is provided on the lower surface of the driving liquid crystal cell (or Or on the upper surface side).
  • the driving liquid crystal cell used in the present invention includes a pair of transparent substrates provided with electrodes, and a nematic liquid crystal layer provided between the transparent substrates and twist-aligned when no voltage is applied.
  • the driving liquid crystal cell used in the present invention includes a type of electrode, a type of transparent substrate, There is no particular limitation on the method of manufacturing the liquid crystal layer and the driving liquid crystal cell, and there is no particular limitation on the driving method.
  • the two polarizing plates sandwiching the driving liquid crystal cell include, for example, a uniaxially stretched polyvinyl alcohol film, a halogen polarizing film in which iodine molecules with a high degree of polarization are arranged in a certain direction, and a polyvinyl dye dyed with a direct dye.
  • a laminated film in which an alcohol film or the like is sandwiched between two appropriate protective films can be used.
  • the two polarizing plates can be arranged so that their transmission axes are orthogonal or parallel to each other, as in a normal TN-LCD.
  • the rubbing direction of the transmission axis and the rubbing direction of the transparent substrate (one of the two transparent substrates included in the driving liquid crystal cell) near the polarizing plate should be orthogonal, parallel, or at an angle of 45 degrees. Is desirable. Therefore, in the NB-TN-LCD of the present invention, the angle between the transmission axes of the two polarizing plates is 70 to 110 °, preferably 75 to 105 °, and more preferably 80 to 100 °.
  • the angle formed by the transmission axis of the polarizing plate and the rubbing direction of the transparent substrate on the side close to the flat plate is 70 to 110 °, preferably 75 to 105 °, more preferably Is between 80 ° and 100 °, or between 10 ° and 20 °, preferably between 15 ° and 15 °, and more preferably between 0 ° and 10 °. It is desirable to arrange a driving liquid crystal cell.
  • the optical compensatory film and the driving liquid crystal cell have the following relationship regardless of whether or not an additional film exhibiting optically negative anisotropy is provided. It is preferable to arrange them.
  • the optical compensation film when the optical compensation film is placed on the upper side of the driving liquid crystal cell, for example, the rubbing direction of the transparent substrate located on the upper side of the driving liquid crystal cell and the slow axis of the liquid crystal molecules in the optical compensation film. And an angle of 70 to 110 °, preferably 75 to 105 °, more preferably 80 to 100 °, or 120 to 20 °, preferably 115 to: L5 °, and It is preferable that the angle be in the range of 110 to 10 °.
  • the optical compensation film is installed on the lower surface side of the driving liquid crystal cell, the rubbing direction of the transparent substrate located on the lower surface side of the driving liquid crystal cell and the slow axis of the liquid crystal molecules on the optical compensation film are formed.
  • the angle satisfies the above requirements.
  • the twisting direction of the orientation in the optical compensation film and the orientation formed by the nematic liquid crystal layer of the driving liquid crystal cell when no voltage is applied is installed so that the twist direction is opposite.
  • the nematic liquid crystal layer of the driving liquid crystal cell used therein has a refractive index anisotropy ⁇ n and a thickness of the liquid crystal layer.
  • the product (And) with d is 2 0 0 ⁇ ⁇ !
  • the twist angle of the liquid crystal when no voltage is applied is 80 ° ⁇ 100 °, preferably 85 ° 995 °.
  • the nd value is larger than 600 nm, there is a concern that coloring may increase due to the coexistence of the optical compensation film, and when the nd value is smaller than 200 nm, the luminance and contrast of the viewing surface may be reduced for the same reason. It may decrease. If the twist angle of the nematic liquid crystal layer when no voltage is applied deviates from the above range, the optical rotation effect cannot be expected, and the display characteristics as NB-TN-LCD deteriorate.
  • the average value of the product ( ⁇ , —,) of the refractive index anisotropy ⁇ and the thickness dt of the film is 200 ⁇ in the optical compensation film incorporated in the NB-TN-LCD of the present invention.
  • m to 600 nm, preferably 300 nm to 500 nm, and the twist angle of the twisted nematic alignment is usually 40 ° to 120 ° as absolute value, preferably 80 °. It is in the range of ° to 100 °.
  • the average of ⁇ , d, and the value of the optical compensation film tied to this is the ⁇ nd value of the nematic liquid crystal layer in the driving liquid crystal cell.
  • the average of the absolute value of the twist angle of the liquid crystal in the optical compensation film is substantially equal to the absolute value of the twist angle of the liquid crystal in the nematic liquid crystal layer, and the twist direction of the liquid crystal in the optical compensation film is The liquid crystal twist direction in the nematic liquid crystal layer is in the opposite relationship.
  • the liquid crystalline polyester had a logarithmic viscosity of 0.17, a nematic phase as a liquid crystal phase, an isotropic-liquid crystal phase transition temperature of 250 ° C or higher, and a glass transition point of 115 ° C. (Polymer 1).
  • Biphenyldicarbonyl chloride (90 mmol) and terefu-yugaguchi yl chloride (10 mmol) 1,2R, 3R-dimethoxybutanediol (105 mmol) were allowed to react in dichloromethane at room temperature for 20 hours. This was poured into methanol and reprecipitated to obtain 12.3 g of a liquid crystalline polyester (polymer 2).
  • Polymer II had a logarithmic viscosity of 0.11, a chiral smectic phase at room temperature, and an isotropic transition temperature of 40 to 50 ° C. Further, T g was considered to be around room temperature, and could not be observed by the measurement using DSC.
  • the refractive index of the liquid crystal of sample 1 was measured by placing the polyimide substrate of sample 1 so as to be in contact with the prism surface of the Abbe refractometer (Type 4 manufactured by Ayago) c
  • the refractive index in the film plane is anisotropic, and the refractive index in the plane perpendicular to the rubbing direction is 1.5. 5.
  • the refractive index in the parallel plane was 1.75, and the refractive index in the film thickness direction was constant at 1.55 regardless of the direction of the sample.
  • sample 1 contains an opaque and optically anisotropic polyimide film
  • a UV-curable adhesive (UV-340, manufactured by Toagosei Co., Ltd.) was applied to the air interface side of sample 1.
  • UV-340 UV-curable adhesive
  • a white sheet glass 1.1 mm thick
  • the adhesive was cured by UV irradiation at about 600 mJ. .
  • peeling the polyimide film from the thus obtained laminate glass / liquid crystal film / polyimide film
  • an optically compensatory film comprising an optically substantially isotropic support and a liquid crystal layer is obtained. A got.
  • Reference example 1 Preparation of optical compensation film B 19.3 g of the polymer 1 obtained in Example 1 and 0.7 g of the polymer 12 were pulverized and mixed, and the mixture was mixed with a glass 2 with polyimide film rubbed with rayon cloth. After sandwiching between the sheets and heat-treating at 240 ° C. for 30 minutes, it was cooled and fixed at room temperature to obtain a uniformly oriented optical compensation film B having an average actual thickness of 2.3. Polarization analysis was performed on the two glasses with polyimide film and the optical compensation film B obtained between them, and it was confirmed that the glass with polyimide film was optically isotropic. In addition, An, d, and the twist angle at any five points of the optical compensation film B were measured, and the results shown in Table 2 were obtained. From this result, it can be seen that ⁇ , d, and the torsion angle are not proportional.
  • Example 2 Liquid crystal display device
  • a TN cell was prepared using the optical compensation film A obtained in Example 1 and the compensating film and the TN cell were disposed between the two polarizing plates. Then, a normally black mode TN liquid crystal display device was created.
  • a rectangular wave of 300 Hz was applied to the liquid crystal cell of this liquid crystal display element, and black display was set to 0 V and white display was set to 6 V.
  • the transmittance of the liquid crystal cell was measured using a color luminance meter BM-5 manufactured by Topcon Corporation, and the contrast ratio was determined from the transmittance ratio (white / black) during black display and white display.
  • Table 3 and FIG. 2 show the contrast ratio of each measurement point based on the contrast ratio of measurement point 2 that gave the highest contrast ratio among the five measurement points. Table 3
  • a normally black mode TN liquid crystal display element was prepared in the same manner as in Example 2, except that the optical compensation film B obtained in Reference Example 1 was used together with two optically isotropic glass plates.
  • the contrast ratio of each measurement point was determined in the same manner as in Example 2.
  • the contrast ratio of each measurement point based on the contrast ratio of measurement point 6 (giving the same contrast ratio as measurement point 2) that gave the highest contrast ratio among the five measurement ffi See Table 4 and Figure 2.
  • Example 4 Liquid crystal display device
  • one optical auxiliary element A was disposed between the two polarizing plates in the cell to produce a normally black mode TN liquid crystal display element.
  • a rectangular wave of 300 Hz is applied to the liquid crystal cell of the liquid crystal display element, the driving voltage is set so that the black display is set to 0 V, the white display is set to 6 V, and the transmittance at the front is divided into eight equal parts.
  • Set. Measure the transmittance of the liquid product cell with respect to the vertically incident light using a color luminance meter BM_5 manufactured by Topcon Corporation, and calculate the contrast ratio from the ratio of the transmittance during black display and white display (white / black).
  • Table 6 and Fig. 4 show the contrast ratio of each measurement point based on the contrast ratio of measurement point 2 that gave the highest contrast ratio among the five measurement points.
  • FIG. 5 shows the obtained gradation characteristics of the left and right viewing angles.
  • Table 8 shows the degree of asymmetry of the left and right gradations.
  • a liquid crystal display element was prepared in the same manner as in Example 4 except that the optical compensation film B obtained in Reference Example 2 was used in place of the optical compensation element A together with two pieces of glass with polyimide film.
  • the display element was evaluated according to Example 4. The results are shown in Tables 7, 8, and 4 and 6.
  • the sulfonic acid anhydride of carboxylic acid was synthesized.
  • Polyvinyl alcohol (Kuraray, trade name: Kuraray Poval MP-203) is evenly applied to a thickness of 0.2 m on a white plate glass (Kuraray Co., Ltd., 1.1 mm in original thickness), and the dried surface is coated. Rubbing treatment was performed with Rayon II.
  • the photocurable low-molecular liquid crystal composition liquid was applied to the surface subjected to the rubbing treatment using a Barco overnight. After the application, it was placed on a hot plate set at 80 ° C and dried for 20 minutes. After drying, the liquid crystal layer had already completed the formation of twisted nematic alignment.
  • the film was put into an oven set at 50 ° C., and UV irradiation was performed while purging with nitrogen until the oxygen concentration became 250 ppm or less.
  • a high-pressure mercury lamp was used as the UV light source, the irradiation intensity was 12 OW / cm 2 , and the total irradiation amount during the irradiation time of 15 seconds was 126 OmJ.
  • the low-molecular liquid crystal layer was hardened, and its surface hardness was about 2 H in pencil hardness.
  • the average actual film thickness of the low-molecular liquid crystal layer measured by thin-film interferometry was 3.36 ⁇ m.
  • the following experiment was performed to measure the refractive index of the liquid crystal layer in the optical compensation film c (low-molecular liquid crystal layer Z polyvinyl alcohol / white plate glass) thus obtained.
  • the photocurable low-molecular liquid crystal composition from which the low-molecular liquid crystal layer was obtained alignment and fixation were performed on a high-refractive-index glass substrate (refractive index: 1.84) with a rubbing polyimide film under the same conditions. Then, a liquid crystal film was prepared, and the refractive index was measured using the liquid crystal film.
  • the glass substrate is placed in contact with the prism surface of the refractometer, and the liquid crystal film is arranged so that the substrate interface side is lower than the air interface side, the refractive index in the film surface is uniaxial and it is in the rubbing direction.
  • the refractive index in the vertical plane was 1.53, the refractive index in the parallel plane was 1.67, and the refractive index in the film thickness direction was constant at 1.53 regardless of the direction of the sample. . From this, it was found that rod-like liquid crystal molecules were planarly aligned on the glass substrate side with respect to the substrate and parallel to the rubbing axis. Also, n of the low molecular liquid crystal layer. , N e has been found that it it 1.5 3 1. 6 which is 7.
  • liquid crystal compound A 2.9 13 g of the liquid crystal compound B and 0.641 g of the liquid crystal compound C were collected, and the photoinitiator Irgacure was added.
  • a liquid crystal composition comprising 0.3 g (manufactured by Ciba Geigy) and a sensitizer (getylthioxanthone) ⁇ .lg was prepared.
  • the obtained composition was sandwiched between two glass substrates provided with a polyimide film rubbed with a rayon cloth and placed in an oven set at 50 ° C. Oxygen in the oven The solution was allowed to cool to the oven set temperature while being purged with nitrogen until the concentration became 250 ppm or less, and UV irradiation was performed at that temperature to fix the twisted nematic alignment structure, thereby obtaining an optical compensation film D.
  • the average actual film thickness of the liquid crystal layer after fixing the orientation obtained between the glass substrates was 3.36 // m.
  • Ellipsometry of the obtained liquid crystal layer was performed, and ⁇ , ⁇ , and torsion angles at arbitrary five points were measured.
  • the results shown in Table 10 were obtained. From this result, it can be seen that the twist angle is constant even if A r ⁇ d i changes, and that ⁇ d, and the twist angle are not in a proportional relationship.
  • Example 6 Liquid crystal display device
  • (Left twist) A TN cell with a pretilt angle of 2 ° was prepared, and one optical compensation film C was used for the cell, as shown in FIG. The cells were arranged to create a normally black mode TN liquid crystal display device.
  • a rectangular wave of 300 Hz was applied to the liquid crystal cell of this liquid crystal display element, and black display was set to 0 V and white display was set to 6 V.
  • the transmittance of the liquid crystal cell was measured using a color luminance meter BM_5 manufactured by Topcon Corporation, and the contrast ratio was determined from the transmittance ratio (white / black) during black display and white display.
  • Table 11 and FIG. 7 show the contrast ratio of each measurement point based on the contrast ratio of measurement point 2 that gave the highest contrast ratio among the five measurement points. Table 11
  • a normally black mode TN liquid crystal display device was prepared in the same manner as in Example 8, except that the optical compensation film C was replaced with the optical compensation film D.
  • the black display was performed on this liquid crystal display device in the same manner as in Example 7.
  • the contrast ratio at the time and white display was determined.
  • the contrast ratio of each measurement point based on the contrast ratio of measurement point 6 (giving the same contrast ratio as measurement point 2) with the highest contrast ratio among the five measured values was calculated. The results are shown in Tables 12 and 7.
  • Example 8 Preparation of optical compensation film F (see 11-140 4)
  • a liquid crystal material for the driving liquid crystal cell is ZL I-4792 manufactured by Merck.
  • an optical compensation film E and a TN cell were disposed between two polarizing plates as shown in Fig. 1 by using one optical compensation film E for the cell.
  • a normally black mode TN liquid crystal display device was created.
  • a normally black mode TN liquid crystal display element was prepared in the same manner as in Example 9 except that the optical compensation film E was replaced with the optical compensation film F.
  • the contrast ratio when displaying and when displaying white was determined.
  • Table 16 shows the contrast ratio of each measurement point based on the contrast ratio of measurement point 6 that gave the highest contrast ratio among the five measured values (given the same contrast ratio as measurement point 2).
  • FIG. 16 shows the contrast ratio of each measurement point based on the contrast ratio of measurement point 6 that gave the highest contrast ratio among the five measured values (given the same contrast ratio as measurement point 2).
  • Example 1 Three samples 1 (liquid crystal film / polyimide film) prepared in Example 1 were prepared, and a UV curable adhesive (UV_340, manufactured by Toagosei Co., Ltd.) was applied to each liquid crystal film surface. It was applied to a thickness of about 5 mm, and the three types of transparent substrates shown in Table 17 were laminated on each, and the adhesive was cured by UV irradiation of about 60 OmJ (transparent Substrate / adhesive film / liquid crystal film / polyimide film) By peeling the middle film, the liquid crystal film was transferred onto each transparent substrate, and three types of optical compensators were obtained. The polarization analysis of each optical compensator was performed, and the ⁇ n, di, and twist angle of the liquid crystal film were measured. As a result, it was confirmed that the angle was 470 nm and the angle was 90 ° (right twist).
  • UV_340 manufactured by Toagosei Co., Ltd.
  • liquid crystal material for the driving liquid crystal cell ZLI-4792 manufactured by Merck Co., Ltd., with a cell gap of 4.8 Andm, And 2 470 nm, twist angle 90 ° (left twist), and pretilt angle 2.
  • TN cell was manufactured.
  • the optical compensator C was arranged in the cell as shown in FIG.
  • Example 12 Liquid crystal display element
  • a liquid crystal display element was prepared in the same manner as in Example 11 except that the optical compensation element C was replaced with the optical compensation element D, and the viewing angle dependence of the gradation characteristics was determined. The obtained gray scale characteristics of the left and right viewing angles are shown in FIG. Example 13 3: Liquid crystal display element
  • Example 7 Liquid crystal display device
  • Example 11 A liquid crystal display element similar to that of Example 11 was prepared except that the optical compensation element C was replaced with the optical compensation element B, and the viewing angle dependence of the gradation characteristics was determined.
  • Fig. 13 shows the obtained gradation characteristics of the left and right viewing angles. Comparative Example 1: Liquid crystal display device
  • FIG. 15 shows the obtained gradation characteristics of the left and right viewing angles.
  • Table 18 shows the results of evaluating left and right asymmetries during halftone display for each of the liquid crystal display elements of Examples 11 to 13, Reference Example 7, and Comparative Example 1.
  • Example 5 Three optical compensation films C (with white plate glass) obtained in Example 5 were prepared, and a UV curable adhesive (UV-3400, manufactured by Toagosei Co., Ltd.) was applied to the surface of each of the low-molecular liquid crystal layers for about 5 minutes. ⁇ M in thickness, and the three types of transparent substrates shown in Table 19 were laminated on top of each other, and the adhesive was cured by UV irradiation of about 60 OmJ. / An optical compensation element having a three-layer structure made of white sheet glass was obtained. Table 19
  • UV curable adhesive UV-3400, manufactured by Toagosei Co., Ltd.
  • Example 15 Liquid crystal display device
  • TN cell was manufactured.
  • the optical compensator F was arranged in the cell as shown in FIG.
  • Example 16 Liquid crystal display element
  • a liquid crystal display element was prepared in the same manner as in Example 15 except that the optical compensation element F was replaced with the optical compensation element G, and the viewing angle dependence of the gradation characteristics was determined.
  • Fig. 17 shows the obtained gradation characteristics of the left and right viewing angles.
  • An optical compensating element ⁇ optical compensating film with a transparent substrate
  • Example 2 Liquid crystal similar to that of Example 15 except that optical compensator E was replaced with optical compensator D A display element was fabricated, and the viewing angle dependence of the gradation characteristics was determined. The obtained gray scale characteristics of the left and right viewing angles are shown in FIG. Comparative Example 2: Liquid crystal display device
  • FIG. 20 shows the obtained gradation characteristics of the left and right viewing angles. Table 20 shows the results of evaluating left and right asymmetries during halftone display for each of the liquid crystal display devices of Examples 15 to 17, Reference Example 8, and Comparative Example 2.

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Abstract

L'invention porte sur un affichage à cristaux liquides nématiques torsadés en mode normalement noir possédant, entre deux polariseurs, une cellule de commande de cristaux liquides comprenant une couche de cristaux liquides nématiques et un film de compensation optique incluant une couche de cristaux liquides dans laquelle un cristal liquide est soumis à un alignement nématique torsadé. La valeur absolue de la moyenne dans le plan de Δn1d1 du film de compensation optique est approximativement égale à Δnd de la couche de cristaux liquides nématiques, le sens de torsion de la couche de cristaux liquides nématiques étant opposé à celui de la couche de cristaux liquides à alignement nématique, et la valeur absolue de la moyenne des angles de torsion de l'alignement nématique torsadé du film de compensation optique étant approximativement égale à celle de la couche de cristaux liquides nématiques.
PCT/JP2000/005132 1999-07-30 2000-07-31 Affichage a cristaux liquides nematiques torsades en mode normalement noir WO2001009674A1 (fr)

Applications Claiming Priority (16)

Application Number Priority Date Filing Date Title
JP11/217842 1999-07-30
JP11217841A JP2001042323A (ja) 1999-07-30 1999-07-30 ノーマリーブラックモード型ｔｎ液晶表示素子
JP11217842A JP2001042325A (ja) 1999-07-30 1999-07-30 光学補償素子
JP11217843A JP2001042122A (ja) 1999-07-30 1999-07-30 光学補償素子
JP11/217843 1999-07-30
JP11/217841 1999-07-30
JP11228204A JP2001051274A (ja) 1999-08-12 1999-08-12 光学補償フィルム
JP11/228206 1999-08-12
JP11/228204 1999-08-12
JP11/228205 1999-08-12
JP11228205A JP2001051118A (ja) 1999-08-12 1999-08-12 光学補償フィルム
JP11228206A JP2001051273A (ja) 1999-08-12 1999-08-12 ノーマリーブラックモード型ｔｎ液晶表示素子
JP37134099A JP2001188231A (ja) 1999-12-27 1999-12-27 ノーマリーブラックモード型ｔｎ液晶表示素子
JP11/371341 1999-12-27
JP11/371340 1999-12-27
JP37134199A JP2001188225A (ja) 1999-12-27 1999-12-27 ノーマリーブラックモード型ｔｎ液晶表示素子

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7166321B2 (en) 2000-12-04 2007-01-23 Fuji Photo Film Co., Ltd. Process for the preparation of an optical compensatory sheet comprising cellulose ester film, orientation layer, and optically anisotropic layer formed of liquid crystal molecules having a fixed alignment

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JPS6478232A (en) * 1987-09-18 1989-03-23 Fujitsu Ltd Liquid crystal display device
JPH05215912A (ja) * 1992-02-07 1993-08-27 Seiko Epson Corp 液晶表示素子
JPH07104284A (ja) * 1993-10-04 1995-04-21 Nec Corp 光学補償板を用いた液晶表示装置
JPH09292611A (ja) * 1996-04-30 1997-11-11 Nec Corp 液晶表示装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6478232A (en) * 1987-09-18 1989-03-23 Fujitsu Ltd Liquid crystal display device
JPH05215912A (ja) * 1992-02-07 1993-08-27 Seiko Epson Corp 液晶表示素子
JPH07104284A (ja) * 1993-10-04 1995-04-21 Nec Corp 光学補償板を用いた液晶表示装置
JPH09292611A (ja) * 1996-04-30 1997-11-11 Nec Corp 液晶表示装置

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7166321B2 (en) 2000-12-04 2007-01-23 Fuji Photo Film Co., Ltd. Process for the preparation of an optical compensatory sheet comprising cellulose ester film, orientation layer, and optically anisotropic layer formed of liquid crystal molecules having a fixed alignment

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