WO2011162188A1 - Plaque de polarisation de diffusion de lumière et dispositif d'affichage à cristaux liquides - Google Patents

Plaque de polarisation de diffusion de lumière et dispositif d'affichage à cristaux liquides Download PDF

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Publication number
WO2011162188A1
WO2011162188A1 PCT/JP2011/063977 JP2011063977W WO2011162188A1 WO 2011162188 A1 WO2011162188 A1 WO 2011162188A1 JP 2011063977 W JP2011063977 W JP 2011063977W WO 2011162188 A1 WO2011162188 A1 WO 2011162188A1
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light
film
light diffusing
polarizing plate
liquid crystal
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PCT/JP2011/063977
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English (en)
Japanese (ja)
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誠治 室
康弘 羽場
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住友化学株式会社
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
    • G02B5/021—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
    • G02B5/0221—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures the surface having an irregular structure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • B29D11/0073—Optical laminates
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
    • G02B5/0236—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place within the volume of the element
    • G02B5/0242—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place within the volume of the element by means of dispersed particles
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0273—Diffusing elements; Afocal elements characterized by the use
    • G02B5/0278—Diffusing elements; Afocal elements characterized by the use used in transmission
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0273—Diffusing elements; Afocal elements characterized by the use
    • G02B5/0294—Diffusing elements; Afocal elements characterized by the use adapted to provide an additional optical effect, e.g. anti-reflection or filter
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • 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
    • G02F1/1303—Apparatus specially adapted to the manufacture of LCDs
    • 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
    • G02F1/133528—Polarisers
    • 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
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133606—Direct backlight including a specially adapted diffusing, scattering or light controlling members
    • G02F1/133607—Direct backlight including a specially adapted diffusing, scattering or light controlling members the light controlling member including light directing or refracting elements, e.g. prisms or lenses
    • 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
    • G02F2201/00—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00
    • G02F2201/50—Protective arrangements

Definitions

  • the present invention relates to a light diffusing polarizing plate and a liquid crystal display device using the light diffusing polarizing plate.
  • a liquid crystal display device includes a backlight device, a liquid crystal panel including a liquid crystal cell, a back side polarizing plate disposed on the backlight side of the liquid crystal cell, and a front side polarizing plate disposed on the viewing side of the liquid crystal cell. , Including.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 2007-94369
  • Patent Document 2 Japanese Patent Application Laid-Open No. 2002-107512
  • a coating liquid containing fine particles is applied onto a substrate.
  • a light diffusion film (light diffusion sheet) having a high-haze light diffusion layer to be formed is disclosed.
  • Patent Document 3 a liquid crystal display provided with a glare-proof layer having a certain level of light diffusibility on the viewing side by dispersing and mixing minute fillers (light diffusing agents).
  • An apparatus is disclosed. By disposing such a light diffusing film or antiglare layer on the viewing side surface of the liquid crystal display device, when the display screen of the liquid crystal display device is observed from an oblique direction, image contrast deterioration and gradation inversion are improved. It is possible to widen the viewing angle.
  • the liquid crystal display device including the light diffusing layer imparted with the light diffusibility by the filler as described above, a wider viewing angle can be obtained by increasing the content of the filler in the light diffusing layer.
  • the light diffusion layer containing a large amount of filler has a high surface roughness. If such a light diffusing layer is disposed on the surface of the display, it is not preferable because the display quality is lowered such as whitening due to reflection of outside light. Note that “whitening” is a phenomenon in which the surface of the screen of the liquid crystal display device looks whitish, and is a phenomenon that is likely to occur particularly in a bright place.
  • an object of the present invention is a polarizing plate provided with a light diffusing function by providing a light diffusing layer, which has a sufficient mechanical strength and has a good image quality when incorporated in a liquid crystal display device. It is an object to provide a polarizing plate and a liquid crystal display device using the same.
  • the present invention is a light diffusing polarizing plate comprising a light diffusing film in which a base film (film) and a light diffusing layer are laminated, a first protective film, and a polarizing film, and the light diffusing polarizing plate
  • the total haze is 20% to 85%
  • the internal haze of the light diffusing polarizing plate is 20% to 85%
  • at least one of the first protective film and the base film is
  • a light diffusing polarizing plate which is a light diffusing agent-containing film containing a light diffusing agent and having a total haze of 10% to 80%.
  • the light diffusing agent-containing film comprises the light diffusing agent and a binder resin, and a difference in refractive index between the light diffusing agent and the binder resin is 0.01. Is 0.2.
  • the light diffusing polarizing plate further includes a second protective film, and the second protective film, the polarizing film, the first protective film, and the light diffusing film are in this order. Is laminated.
  • the first protective film and the light diffusing film are bonded via an adhesive layer or an adhesive layer.
  • L 1 is equal to or less than 0.01% 0.0002% or more.
  • a backlight device, a light diffusing means, a backlight side polarizing plate, a liquid crystal cell, and the light diffusing polarizing plate are arranged in this order, and are close to the liquid crystal cell.
  • a liquid crystal display device in which the light diffusing polarizing plate is arranged so that the polarizing film and the light diffusing film are located in this order from the side.
  • the light emitted from the light diffusing means has a luminance in a direction inclined by 70 ° from the normal direction of the light diffusing means with respect to the luminance in the normal direction of the light diffusing means. %, And the emitted light preferably includes non-parallel light.
  • the light diffusing means includes, for example, a light diffusing plate and a light deflecting plate, and the light diffusing plate and the light deflecting plate are arranged in this order from the backlight device side.
  • liquid crystal cell a TN (twisted nematic) liquid crystal cell, an IPS (in-plane switching) liquid crystal cell, a VA (vertical alignment) liquid crystal cell, or the like can be used.
  • TN twisted nematic
  • IPS in-plane switching
  • VA vertical alignment
  • a polarizing plate provided with a light diffusing function by providing a light diffusing layer has sufficient mechanical strength, and displays a good image quality when incorporated in a liquid crystal display device.
  • a polarizing plate can be provided.
  • the liquid crystal display device of the present invention to which the light diffusing polarizing plate is applied can display a good image quality.
  • the light diffusing polarizing plate according to the present invention includes a polarizing film, a first protective film, a light diffusing film in which a base film and a light diffusing layer are laminated.
  • the total haze of the light diffusing polarizing plate is 20% to 85%, and the internal haze is 20% to 85%.
  • At least one of the first protective film and the base film is a light diffusing agent-containing film containing a light diffusing agent and having a total haze of 10% to 80%.
  • the liquid crystal display device of the present invention to which the light diffusing polarizing plate is applied can display a good image quality.
  • the total light transmittance (Tt) is the sum of the parallel light transmittance (Tp) and the diffuse light transmittance (Td) that are transmitted coaxially with the incident light.
  • the total light transmittance (Tt) and the diffused light transmittance (Td) are values measured in accordance with JIS K 7361.
  • the “internal haze” of the light diffusing polarizing plate is a haze other than the haze (surface haze) due to the surface shape of the light diffusing polarizing plate among all the hazes.
  • the total haze and / or internal haze When the total haze and / or internal haze is less than 20%, the light scattering property is insufficient and the viewing angle may be narrowed. Further, when the total haze and / or internal haze exceeds 85%, light scattering is too strong. Therefore, when the light diffusing polarizing plate is applied to a liquid crystal display device, for example, in the black display, the front direction of the liquid crystal display device However, the front contrast is lowered due to the fact that light leaking obliquely is scattered in the front direction and the display quality is deteriorated. Further, when the total haze and / or internal haze exceeds 85%, the transparency of the light diffusing polarizing plate tends to be impaired. More preferably, the total haze and the internal haze are 50% or more and 85% or less, respectively.
  • the total haze, internal haze, and surface haze of the light diffusing polarizing plate are specifically measured as follows.
  • the total haze is measured by using a haze transmittance meter in accordance with JIS K 7136 (for example, a haze meter “HM-150” manufactured by Murakami Color Research Laboratory Co., Ltd.) and total light transmittance (Tt) and diffuse light transmittance. (Td) is measured and calculated by the above formula (1).
  • a triacetyl cellulose film having a haze of approximately 0% is bonded to the light exit surface of the light diffusing polarizing plate using glycerin, and the haze is measured in the same manner as the measurement of the total haze described above.
  • the surface haze caused by the surface shape of the light diffusing polarizing plate is preferably 2% or less. When the surface haze exceeds 2%, whitening tends to occur due to surface irregular reflection. In order to prevent whitening more effectively, the surface haze is preferably 1% or less.
  • Ratio L 2 / L 1 of the intensity L 2 of the laser beam emitted in the direction inclined by 40 ° from the normal direction with respect to the intensity L 1 of the laser beam incident in the normal direction of the light diffusing polarizing plate is preferably 0.0002% or more and 0.01% or less.
  • the relative scattered light intensity will be described with reference to FIG.
  • FIG. 1 is a perspective view schematically showing an incident direction of laser light and a transmitted scattered light intensity measurement direction in a light diffusing polarizing plate.
  • a laser beam He having a wavelength of 543.5 nm and an intensity of L 1 incident from the incident surface side of light diffusing polarizing plate 10 in the direction of normal A1 of light diffusing polarizing plate 10 is shown.
  • the relative scattered light intensity L 2 / L 1 is preferably in the range of 0.0002% to 0.01%.
  • the relative scattered light intensity L 2 / L 1 is less than 0.0002%, the light scattering property is insufficient and the viewing angle becomes narrow. If it exceeds 0.01%, light scattering is too strong, so when a light diffusing polarizing plate is applied to a liquid crystal display device, for example, in black display, it leaks obliquely with respect to the front direction of the liquid crystal display device. The front contrast is lowered due to the fact that the emitted light is scattered in the front direction by the light diffusion layer, and the display quality is deteriorated.
  • the relative scattered light intensity L 2 / L 1 is more preferably 0.0003% or more and 0.001% or less.
  • an optical power meter for example, “3292 03 optical power sensor” manufactured by Yokogawa Electric Corporation and “3292 optical power meter” manufactured by the same company.
  • the total haze of the light diffusing agent-containing film is 10% or more and 80% or less. Since the light diffusing polarizing plate according to the present invention has such a light diffusing agent-containing film, even if the light diffusing layer of the light diffusing film does not have high diffusibility, the light diffusing polarizing plate as a whole A desired haze can be achieved. Therefore, sufficient light diffusibility can be ensured as a whole.
  • the total haze of the light diffusing agent-containing film can be measured by the same method as the total haze of the light diffusing polarizing plate.
  • FIG. 2 is a schematic cross-sectional view showing the light diffusable polarizing plate of the first embodiment.
  • the light diffusing polarizing plate 100 has a polarizing film 101, and an upper protective film 110 and a light diffusing film 102 are laminated in this order on one surface of the polarizing film 101, and the other surface of the polarizing film 101.
  • a lower protective film 109 is laminated.
  • the light diffusion film 102 includes a base film 105 and a light diffusion layer 106 laminated on the base film 105.
  • At least one of the upper protective film 110, the lower protective film 109 and the base film 105 is a light diffusing agent-containing film containing a light diffusing agent and having a total haze of 10% to 80%.
  • at least one of the upper protective film 110 and the base film 105 is the light diffusing agent-containing film. More preferably, both the upper protective film 110 and the base film 105 are the light diffusing agent-containing films.
  • the polarizing film 101 for example, a film made of a polyvinyl alcohol resin, a polyvinyl acetate resin, an ethylene / vinyl acetate (EVA) resin, a polyamide resin, a polyester resin, etc., and a dichroic dye adsorbed and oriented, a molecule A polyvinyl alcohol / polyvinylene copolymer containing an oriented molecular chain of a dichroic dehydrated product of polyvinyl alcohol (polyvinylene) in a partially oriented polyvinyl alcohol film.
  • EVA ethylene / vinyl acetate
  • a dichroic dye adsorbed and oriented a molecule A polyvinyl alcohol / polyvinylene copolymer containing an oriented molecular chain of a dichroic dehydrated product of polyvinyl alcohol (polyvinylene) in a partially oriented polyvinyl alcohol film.
  • polyvinyl alcohol resin a saponified polyvinyl acetate resin
  • examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers with other monomers copolymerizable with vinyl acetate.
  • examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.
  • the saponification degree of the polyvinyl alcohol-based resin is preferably 98.0 mol% or more. If the saponification degree is less than 98.0 mol%, sufficient optical performance may not be obtained.
  • the saponification degree as used herein is a unit ratio (mol%) representing the ratio of the acetate group contained in the polyvinyl acetate resin, which is a raw material for the polyvinyl alcohol resin, to a hydroxyl group by the saponification step. Is a numerical value defined by the following formula. It can be determined by the method defined in JIS K K 6726 (1994).
  • the polyvinyl alcohol resin used in the present embodiment may be a modified polyvinyl alcohol partially modified.
  • polyvinyl alcohol-based resins modified with olefins such as ethylene and propylene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, alkyl esters of unsaturated carboxylic acids, acrylamide, etc. The average degree of polymerization of the polyvinyl alcohol resin is not particularly limited, but is preferably 100 to 10,000, and more preferably 1500 to 10,000.
  • polyvinyl alcohol-based resin having such characteristics include PVA124H (degree of saponification: 99.9 mol% or more), PVA124 (degree of saponification: 98.0 to 99.0 mol%) manufactured by Kuraray Co., Ltd.
  • PVA117H degree of saponification: 99.3 mol% or more
  • PVA117 degree of saponification: 98.0 to 99.0 mol%)
  • NH-18 degree of saponification: Nippon Synthetic Chemical Industry Co., Ltd.
  • N-300 degree of saponification: 98.0 to 99.0 mol%)
  • JF-17 degree of saponification: 98 manufactured by Nihon Acetate Bipoar Co., Ltd.
  • JF-17L degree of saponification: 98.0-99.0 mol%)
  • JF-20 degree of saponification: 98.0-99.0 mol%) and the like.
  • a film obtained by forming such a polyvinyl alcohol-based resin constitutes the polarizing film 101 according to the present embodiment.
  • the method for forming a polyvinyl alcohol-based resin is not particularly limited, and can be formed by a known method.
  • the polarizing film 101 is preferably uniaxially stretched at a stretch ratio of more than 5 times, more preferably more than 5 times and not more than 17 times.
  • the thickness of the polarizing film 101 is not particularly limited, but is generally preferably 100 ⁇ m or less, more preferably in the range of 10 to 50 ⁇ m, and still more preferably in the range of 25 to 35 ⁇ m from the viewpoint of thinning the polarizing plate.
  • At least one of the upper protective film 110, the lower protective film 109, and the base film 105 shown in FIG. 2 is a light diffusing agent-containing film.
  • FIG. 3 is a schematic cross-sectional view showing a preferred example of a light diffusing agent-containing film.
  • the light diffusing agent-containing film 200 shown in FIG. 3 has a three-layer structure in which a light diffusing layer 204 is sandwiched between two transparent resin layers 203.
  • the light diffusing agent-containing film 200 including the transparent resin layer 203 having a smooth surface is easily produced without being affected by the surface unevenness of the light diffusing layer 204.
  • the light diffusion layer 204 includes a binder resin 204b and a light diffusing agent 204a dispersed in the binder resin 204.
  • a substantially optically transparent resin is used for the transparent resin used for the transparent resin layer 203 constituting the light diffusing agent-containing film and the binder resin 204b used for the light diffusing layer 204.
  • resins include triacetyl cellulose; polyethylene terephthalate; acrylic resins such as polymethylmethacrylate; polycarbonate resins; thermoplastic resins such as amorphous cyclic polyolefins using norbornene compounds as monomers. it can.
  • the transparent resin constituting the transparent resin layer 203 and the binder resin 204b used for the light diffusion layer 204 may be the same or different materials.
  • the acrylic resin means a material obtained by mixing, melting, and kneading a methacrylic resin and an additive added as necessary.
  • the methacrylic resin is a polymer mainly composed of methacrylic acid ester.
  • the methacrylic resin may be a homopolymer of one kind of methacrylic acid ester or a copolymer of methacrylic acid ester with other methacrylic acid ester or acrylic acid ester.
  • the methacrylic acid esters include alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate.
  • the alkyl group of the alkyl methacrylate usually has about 1 to 4 carbon atoms.
  • the acrylic ester that can be copolymerized with the methacrylic ester is preferably an alkyl acrylate, such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, or the like.
  • the alkyl group of the alkyl acrylate usually has about 1 to 8 carbon atoms.
  • a copolymer mainly composed of a methacrylic acid ester is a copolymer component comprising a compound having at least one polymerizable carbon-carbon double bond in the molecule, such as an aromatic vinyl compound such as styrene and a vinylcyan compound such as acrylonitrile. May be included.
  • the acrylic resin preferably contains acrylic rubber particles in order to improve the impact resistance and film forming property of the film.
  • the amount of acrylic rubber particles that can be contained in the acrylic resin is preferably 5% by weight or more, more preferably 10% by weight or more.
  • the upper limit of the amount of the acrylic rubber particles is not critical, but if the amount of the acrylic rubber particles is too large, the surface hardness of the film is lowered, and when the film is subjected to surface treatment, it is resistant to the organic solvent in the surface treatment agent. Solvent property decreases. Therefore, the amount of acrylic rubber particles that can be contained in the acrylic resin is preferably 80% by weight or less, and more preferably 60% by weight or less.
  • the acrylic rubber particles are particles containing an elastic polymer mainly composed of an acrylate ester as an essential component.
  • the acrylic rubber particles may have a single-layer structure consisting essentially only of the elastic polymer. It may have a multi-layer structure in which the coalescence is one layer.
  • the elastic polymer 50 to 99.9% by weight of an alkyl acrylate and 0 to 49.9% by weight of at least one other vinyl monomer copolymerizable therewith, A cross-linked elastic copolymer obtained by polymerization of a monomer mixture composed of 0.1 to 10% by weight of a polymerizable cross-linkable monomer is preferably used.
  • alkyl acrylate examples include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and the like.
  • the alkyl group of the alkyl acrylate usually has about 1 to 8 carbon atoms.
  • examples of other vinyl monomers copolymerizable with the above alkyl acrylate include compounds having one polymerizable carbon-carbon double bond in the molecule, and more specifically, methacrylic monomers.
  • Methacrylic acid esters such as methyl acid
  • Aromatic vinyl compounds such as styrene
  • Vinyl cyanide compounds such as acrylonitrile.
  • Examples of the copolymerizable crosslinkable monomer include a crosslinkable compound having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, ethylene glycol diester.
  • (Meth) acrylates of polyhydric alcohols such as (meth) acrylate and butanediol di (meth) acrylate; alkenyl esters of (meth) acrylic acid such as allyl (meth) acrylate and methallyl (meth) acrylate; divinylbenzene, etc. Is mentioned.
  • (meth) acrylate refers to methacrylate or acrylate
  • (meth) acrylic acid refers to methacrylic acid or acrylic acid.
  • the acrylic resin contains normal additives such as ultraviolet absorbers, organic dyes, pigments, inorganic dyes, antioxidants, antistatic agents, surfactants, and the like. Also good. Among these, an ultraviolet absorber is preferably used for improving weather resistance.
  • UV absorbers examples include 2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol], 2- (5 -Methyl-2-hydroxyphenyl) -2H-benzotriazole, 2- [2-hydroxy-3,5-bis ( ⁇ , ⁇ -dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (3,5-di -Tert-butyl-2-hydroxyphenyl) -2H-benzotriazole, 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5-chloro-2H-benzotriazole, 2- (3,5 -Di-tert-butyl-2-hydroxyphenyl) -5-chloro-2H-benzotriazole, 2- (3,5-di-tert-amyl-2-hydroxypheny ) Benzotriazole UV absorbers such as -2H-benzotriazo
  • the refractive index of the light diffusing agent 204a dispersed in the light diffusing layer 204 needs to have a value different from the refractive index of the binder resin 204b in order to impart a light diffusing function to the light diffusing agent-containing film.
  • the difference in refractive index between the two is preferably 0.01 to 0.2, and particularly preferably 0.05 to 0.1. When the refractive index difference is larger than 0.2, strong scattering is likely to occur even when the content of the light diffusing agent 204a is small, and it becomes difficult to control the scattering.
  • the refractive index of the light diffusing agent 204a is appropriately selected in consideration of the type of the binder resin 204b to be used and the like.
  • the refractive index of the light diffusing agent 204a is 1.4. It is preferable to select from the range of 1.6 or less.
  • the refractive index of the light diffusing agent 204a is about 1.29 to 1.69 because the refractive index of the acrylic resin is generally about 1.49. From this range, it is preferable to select so as to satisfy the above conditions.
  • the light diffusing agent 204a is preferably spherical or almost spherical in consideration of the isotropic and uniformity of scattering. In addition, particles having a shape with irregularities on the surface and amorphous particles are not preferable because unexpected scattering may occur due to a structure such as minute irregularities on the surface smaller than the particle size.
  • the weight average particle diameter of the light diffusing agent 204a is preferably 1 ⁇ m or more and 20 ⁇ m or less, and more preferably 2 ⁇ m or more and 15 ⁇ m or less.
  • the weight average particle diameter of the light diffusing agent 204a is less than 1 ⁇ m, the scattered light intensity on the wide angle side increases, and the contrast tends to decrease when the light diffusing polarizing plate is applied to a liquid crystal display device. Moreover, when the weight average particle diameter exceeds 20 ⁇ m, the required scattering effect may not be obtained, or it may be necessary to increase the thickness of the light diffusing agent-containing film in order to obtain the required scattering effect.
  • Organic fine particles include, for example, melamine beads (refractive index 1.57); (meth) acrylic resin beads such as polymethyl methacrylate beads (refractive index 1.49); methyl methacrylate / styrene copolymer resin beads ( Refractive index 1.50-1.59); Polycarbonate beads (refractive index 1.59); Polyolefin beads such as polyethylene beads (refractive index 1.53) and polypropylene beads; Polyvinyl chloride beads (refractive index 1.46) ); Silicone resin beads (refractive index 1.46); polystyrene beads and the like.
  • Resin beads made of a copolymer obtained by copolymerizing two or more monomers selected from ethylene, propylene, styrene, methyl methacrylate, benzoguanamine, formaldehyde, melamine, butadiene, and the like can also be used.
  • Inorganic fine particles include calcium carbonate, barium sulfate, titanium oxide, aluminum hydroxide, silica, glass, talc, mica, white carbon, magnesium oxide, zinc oxide, and other inorganic fine particles, and these inorganic particles are surface treated with fatty acids.
  • the ones that have been given can be listed as typical ones.
  • the light diffusing agent 204a is preferably contained in an amount of 0.5 to 40 parts by weight, particularly 1 to 20 parts by weight, based on 100 parts by weight of the binder resin.
  • the content of the light diffusing agent 204a is less than 0.5 parts by weight, sufficient light diffusibility tends not to be obtained.
  • the content of the light diffusing agent 204a exceeds 40 parts by weight, it becomes difficult to form the light diffusing agent-containing film or the mechanical strength of the light diffusing agent-containing film tends to be low.
  • the resin composition used to form the light diffusion layer 204 is obtained by mixing the binder resin 204b (for example, methacrylic resin, acrylic rubber particles and other additives) and the light diffusion agent 204a, and melt-kneading them. be able to.
  • binder resin 204b for example, methacrylic resin, acrylic rubber particles and other additives
  • a feed Various generally known methods such as a method using a block and a method using a multi-manifold die can be used. Among them, for example, a method of laminating via a feed block, multilayer melt extrusion from a T die, and forming a film by contacting at least one side of the obtained laminated film-like material with a roll or a belt has good surface properties. That is, it is preferable in that a diffusion film having a smooth transparent resin layer surface can be obtained.
  • a film is formed by bringing both surfaces of the laminated film obtained by the multilayer melt extrusion molding into contact with the roll surface or the belt surface.
  • the method is preferred.
  • the surface of the roll or belt in contact with the transparent resin constituting the transparent resin layer 203 is preferably a mirror surface in order to impart smoothness to the surface of the transparent resin layer 203.
  • a light diffusing agent-containing film can be produced with high productivity as compared to a method of coating a resin liquid containing the light diffusing agent 204a on a base film.
  • a light diffusing agent-containing film with a smooth surface of the transparent resin layer 203 can be easily obtained.
  • the surface of at least one transparent resin layer 203 of the light diffusing agent-containing film is made smooth to bond the surface of the transparent resin layer 203 and another layer via an adhesive layer or a pressure-sensitive adhesive layer.
  • the total haze of the light diffusing agent-containing film 200 is 10% or more and 80% or less as described above.
  • FIG. 4 is a schematic cross-sectional view showing another preferred example of the light diffusing agent-containing film.
  • a light diffusion containing film 210 shown in FIG. 4 includes a light diffusion layer 204 and a transparent resin layer 203 laminated on one surface of the light diffusion layer 204.
  • the light diffusing agent-containing film 200 described above with reference to FIG. 3 has the same structure as that of the light diffusing layer 204 and the structure of the transparent resin layer 203, except that only one transparent resin layer 203 is provided and the entire structure is a two-layer structure. Since it is the same as that of FIG.
  • FIG. 5 is a schematic cross-sectional view showing another preferred example of the light diffusing agent-containing film.
  • the light diffusion containing film 220 shown in FIG. The configuration of the light diffusion layer 204 is the same as that of the light diffusing agent-containing film 200 described above with reference to FIG.
  • the light diffusion film 102 includes a base film 105 and a light diffusion layer 106 laminated on the base film 105.
  • the light diffusing layer 106 is a layer having a translucent resin 106b as a base material, and the light diffusing agent 106a is dispersed in the translucent resin 106b.
  • the light diffusing film 106 may have a light diffusing layer 702 whose surface is constituted by an uneven surface or a flat surface. Note that another layer (including an adhesive layer) may be provided between the base film 105 and the light diffusion layer 106.
  • the base film 105 of the light diffusing film 102 may be a light-transmitting film, and for example, glass or plastic film can be used.
  • the plastic film only needs to have appropriate transparency and mechanical strength. Specific examples include cellulose acetate resins such as TAC (triacetyl cellulose), acrylic resins, polycarbonate resins, and polyester resins such as polyethylene terephthalate.
  • the base film 105 may be a light diffusing agent-containing film as described above.
  • the layer thickness of the base film 105 is, for example, 10 to 500 ⁇ m, preferably 20 to 300 ⁇ m.
  • the light diffusing layer 106 is a layer having a light transmissive resin 106b as a base material, and a light diffusing agent 106a is dispersed in the light transmissive resin 106b.
  • the translucent resin 106b is not particularly limited as long as it has translucency.
  • an ionizing radiation curable resin such as an ultraviolet curable resin or an electron beam curable resin or a cured product of a thermosetting resin, A thermoplastic resin, a cured product of metal alkoxide, or the like can be used.
  • an ionizing radiation curable resin is preferable because it has high hardness and can impart high scratch resistance as a light diffusion film provided on the surface of the liquid crystal display device.
  • the translucent resin 106b is formed by curing the resin by irradiation or heating with ionizing radiation.
  • the ionizing radiation curable resin examples include polyfunctional acrylates such as polyhydric alcohol acrylic acid or methacrylic acid ester; polyisocyanates synthesized from diisocyanate, polyhydric alcohol and acrylic acid or methacrylic acid hydroxy ester, and the like.
  • polyfunctional acrylates such as polyhydric alcohol acrylic acid or methacrylic acid ester
  • Examples include functional urethane acrylate.
  • polyether resins having an acrylate functional group polyester resins, epoxy resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, and the like can also be used.
  • thermosetting resin examples include a phenol resin, a urea melamine resin, an epoxy resin, an unsaturated polyester resin, and a silicone resin in addition to a thermosetting urethane resin composed of an acrylic polyol and an isocyanate prepolymer.
  • thermoplastic resins include cellulose derivatives such as acetylcellulose, nitrocellulose, acetylbutylcellulose, ethylcellulose, and methylcellulose; vinyl acetate and copolymers thereof, vinyl chloride and copolymers thereof, vinylidene chloride and copolymers thereof, and the like.
  • Acetal resins such as polyvinyl formal and polyvinyl butyral; Acrylic resins and copolymers thereof, Acrylic resins such as methacrylic resins and copolymers; Polystyrene resins; Polyamide resins; Polyester resins; Polycarbonate resins Etc.
  • a silicon oxide matrix made of a silicon alkoxide material can be used. Specifically, it is tetramethoxysilane, tetraethoxysilane, or the like, and can be made into an inorganic or organic-inorganic composite matrix (translucent resin) by hydrolysis or dehydration condensation.
  • organic fine particles or inorganic fine particles having translucency can be used as the light diffusing agent 106a in the light diffusing layer 106.
  • organic fine particles made of acrylic resin, melamine resin, polyethylene, polystyrene, organic silicone resin, acrylic-styrene copolymer, etc., and made of calcium carbonate, silica, aluminum oxide, barium carbonate, barium sulfate, titanium oxide, glass, etc.
  • examples include inorganic fine particles.
  • Organic polymer balloons and glass hollow beads can also be used.
  • the light diffusing agent 106a may be composed of one kind of fine particles or may contain two or more kinds of fine particles.
  • the shape of the light diffusing agent 106a may be any of a spherical shape, a flat shape, a plate shape, a needle shape, an indefinite shape, and the like, but a spherical shape or a substantially spherical shape is preferable.
  • the weight average particle diameter of the light diffusing agent 106a is preferably 0.1 ⁇ m or more and 15 ⁇ m or less, and more preferably 1 ⁇ m or more and 10 ⁇ m or less.
  • the weight average particle size of the light diffusing agent 106a is less than 0.1 ⁇ m, visible light having a wavelength region of 380 nm to 800 nm cannot be sufficiently scattered, and the light diffusing property of the light diffusing film 701 becomes insufficient, and the relative scattered light It may be difficult to make the intensity L 2 / L 1 0.0002% or more, and as a result, a wide viewing angle may not be obtained.
  • the weight average particle size exceeds 15 ⁇ m, sufficient light scattering properties may not be obtained, and the relative scattered light intensity L 2 / L 1 may not be 0.0002% or more.
  • the ratio of the standard deviation of the particle size to the weight average particle size (standard deviation / weight average particle size) of the light diffusing agent 106a is preferably 0.5 or less, and more preferably 0.4 or less. When the ratio exceeds 0.5, a light diffusing agent having an extremely large particle size may be included, and protrusion-like defects may occur frequently on the surface of the light diffusing layer. Doing so will cause a reduction in display quality.
  • the weight average particle diameter and the standard deviation of the particle diameter of the light diffusing agent 106a are measured using a Coulter Multisizer (manufactured by Beckman Coulter, Inc.) based on the Coulter principle (pore electrical resistance method).
  • the content of the light diffusing agent 106a in the light diffusion layer 106 is preferably 5 parts by weight or more and 100 parts by weight or less, with respect to 100 parts by weight of the translucent resin 106b, and is 10 parts by weight or more and 40 parts by weight or less. It is more preferable.
  • the refractive index difference between the light diffusing agent 106a and the translucent resin 106b is preferably in the range of 0.01 to 0.2, and more preferably 0.05 to 0.15.
  • the surface of the light diffusion layer 106 (the surface opposite to the base film 105) is formed only by the light-transmitting resin 106b. That is, it is preferable that the light diffusing agent 106 a does not protrude from the surface of the light diffusing layer 106 and is completely buried in the light diffusing layer 106.
  • the layer thickness of the light diffusion layer 106 is preferably 1 to 3 times the weight average particle diameter of the light diffusion agent 106a.
  • the layer thickness of the light diffusing layer 106 is less than 1 times the weight average particle diameter of the light diffusing agent 106 a, the light diffusing agent 106 a easily protrudes from the surface of the light diffusing layer 106. Further, when the layer thickness of the light diffusion layer 106 exceeds three times the weight average particle diameter of the light diffusion agent 106a, the layer thickness of the light diffusion layer 106 becomes too thick.
  • the layer thickness of the light diffusion layer 106 is preferably in the range of 1 to 30 ⁇ m.
  • the layer thickness of the light diffusing layer 106 is less than 1 ⁇ m, sufficient scratch resistance may not be exhibited when the light diffusing polarizing plate is disposed on the viewing side surface of the liquid crystal display device.
  • the layer thickness exceeds 30 ⁇ m, the amount of curl generated in the produced light diffusion film becomes large, and the handleability in pasting to other layers becomes poor.
  • coating of the resin liquid containing the light-diffusion agent 106a and the translucent resin 106b on the base film 105 is a gravure coat method, a micro gravure coat method, a rod coat method, a knife coat method, An air knife coating method, a kiss coating method, a die coating method, or the like can be used.
  • the coating film thickness is adjusted so that the thickness of the light diffusion layer 106 is 1 to 3 times the weight average particle diameter of the translucent fine particles 106b. It is preferable to do.
  • Various surface treatments may be applied to the surface of the base film 105 (surface on the light diffusion layer side) for the purpose of improving the coating property of the resin liquid or improving the adhesion with the light diffusion layer 106.
  • the surface treatment include corona discharge treatment, glow discharge treatment, acid surface treatment, alkali surface treatment, and ultraviolet irradiation treatment.
  • another layer such as a primer layer (easily adhesive layer) may be formed on the base film 105, and the resin liquid may be applied on the other layer.
  • the light diffusing film 102 can also be obtained by applying a resin liquid in which the light diffusing agent 106a is dispersed on the base film 105 and then transferring the mirror surface or uneven surface of the mold to the surface of the layer made of the resin liquid.
  • a light diffusion layer having a flat surface can be formed by transferring the mirror surface by bringing the mirror surface of a mold having a mirror surface (mirror surface mold) into close contact with the surface of the layer made of the resin liquid.
  • the light diffusing layer having the uneven surface shape as shown in FIG. 2 has the uneven surface of the mold (embossing mold) having an uneven surface adhered to the surface of the layer made of the resin liquid. An uneven surface can be transferred and formed.
  • the mirror surface mold may be a mirror surface metal roll, and the embossing mold may be an embossing metal roll.
  • thermosetting resin or metal alkoxide is used as the resin for forming the translucent resin 106b, a layer made of the above resin solution is formed and dried (removing the solvent) as necessary.
  • the surface of the layer made of the resin liquid is in close contact with or close to the mold mirror surface or uneven surface, and then irradiated with ionizing radiation (when using ionizing radiation curable resin) or heated (thermosetting)
  • the layer made of the resin liquid is cured by using a mold resin or metal alkoxide.
  • the ionizing radiation can be appropriately selected from ultraviolet rays, electron beams, near ultraviolet rays, visible light, near infrared rays, infrared rays, X-rays, etc. depending on the type of resin contained in the resin liquid.
  • ultraviolet rays An electron beam is preferable, and ultraviolet rays are particularly preferable because of easy handling and high energy.
  • a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used.
  • An ArF excimer laser, a KrF excimer laser, an excimer lamp, synchrotron radiation, or the like can also be used.
  • an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a xenon arc, and a metal halide lamp are preferably used.
  • the electron beam 50 to 1000 keV emitted from various electron beam accelerators such as Cockloft Walton type, Bande graph type, resonance transformation type, insulation core transformation type, linear type, dynamitron type, and high frequency type, preferably 100 Mention may be made of electron beams having an energy of ⁇ 300 keV.
  • various electron beam accelerators such as Cockloft Walton type, Bande graph type, resonance transformation type, insulation core transformation type, linear type, dynamitron type, and high frequency type, preferably 100 Mention may be made of electron beams having an energy of ⁇ 300 keV.
  • the manufacturing method in order to continuously manufacture the light diffusion film 102, a step of continuously feeding the base film 105 wound in a roll shape, a resin liquid in which the light diffusion agent 106a is dispersed And a step of drying as necessary, a step of curing a layer made of a resin liquid, and a step of winding up the obtained light diffusion film 102.
  • FIG. 6 is a schematic diagram showing a configuration of a manufacturing apparatus for carrying out such a manufacturing method.
  • the base film 105 is continuously unwound by the unwinding device 301.
  • a resin liquid in which the light diffusing agent 106a is dispersed is applied onto the unwound base film 105 using a coating device 302 and a backup roll 303 facing the coating device 302.
  • the resin liquid is dried by passing it through a dryer 304.
  • the base film 105 provided with the layer made of the resin liquid is placed between the mirror metal roll or the embossing metal roll 305 and the nip roll 306, and the layer made of the resin liquid is a mirror metal roll or It winds so that it may contact
  • adhere with the metal roll 305 for embossing Thereby, the mirror surface of the mirror surface metal roll or the uneven surface of the metal roll for embossing is transferred to the surface of the layer made of the resin liquid.
  • a layer made of a resin liquid is obtained by irradiating ultraviolet rays from an ultraviolet irradiation device 308 through the base film 105 in a state where the base film 105 is wound around a mirror surface metal roll or an embossing metal roll 305. Is cured. Since the irradiated surface becomes high temperature due to ultraviolet irradiation, the mirror surface metal roll or the embossing metal roll 305 preferably includes a cooling device for adjusting the surface temperature to about room temperature to 80 ° C. . Further, one or a plurality of ultraviolet irradiation devices 308 can be used.
  • the base film 105 (light diffusion film 102) on which the light diffusion layer 106 is formed is peeled off from the mirror surface metal roll or the embossing metal roll 305 by the peeling roll 307.
  • the light diffusion film 102 produced as described above is taken up by the take-up device 309. At this time, for the purpose of protecting the light diffusing layer 106, it is wound up with a surface protective film made of polyethylene terephthalate, polyethylene, or the like attached to the surface of the light diffusing layer 106 through an adhesive layer having removability. Also good.
  • additional ultraviolet irradiation may be performed after peeling from the mirror surface metal roll or the embossing metal roll 305 by the peeling roll 307.
  • additional ultraviolet irradiation may be performed instead of performing ultraviolet irradiation in a state of being wound around a mirror surface metal roll or an embossing metal roll 305, a base film 105 on which a layer made of an uncured resin liquid is formed is used as a mirror surface metal roll or After peeling from the embossing metal roll 305, it may be cured by irradiation with ultraviolet rays.
  • the upper protective film 110 and the lower protective film 109 can be composed of the above-described light diffusing agent-containing film.
  • the upper protective film 110 and the lower protective film 109 can be composed of the above-described light diffusing agent-containing film.
  • a case other than the above-described light diffusing agent-containing protective film will be described.
  • the protective films 109 and 110 a simple protective film having no optical function may be used, or a protective film having an optical function such as a retardation film or a brightness enhancement film may be used.
  • the material of the protective films 109 and 110 is not particularly limited, but examples thereof include a cyclic polyolefin resin film, a cellulose acetate resin film made of a resin such as triacetyl cellulose and diacetyl cellulose, polyethylene terephthalate, and polyethylene naphthalate. Examples thereof include films that have been widely used in the art, such as polyester resin films made of resins such as phthalate and polybutylene terephthalate, polycarbonate resin films, acrylic resin films, and polypropylene resin films.
  • cyclic polyolefin-based resin examples include appropriate commercial products such as Topas (registered trademark) (manufactured by Ticona), Arton (registered trademark) (manufactured by JSR Corporation), ZEONOR (registered trademark) (Nippon ZEON ( ZEONEX (registered trademark) (manufactured by Nippon Zeon Co., Ltd.), Apel (registered trademark) (manufactured by Mitsui Chemicals, Inc.) can be suitably used.
  • Topas registered trademark
  • Arton registered trademark
  • ZEONOR registered trademark
  • Nippon ZEON ZEONEX
  • Apel registered trademark
  • Mitsui Chemicals, Inc. a known method such as a solvent casting method or a melt extrusion method is appropriately used.
  • cyclic polyolefins such as Essina (registered trademark) (manufactured by Sekisui Chemical Co., Ltd.), SCA40 (manufactured by Sekisui Chemical Co., Ltd.), ZEONOR (registered trademark) film (manufactured by Optes Co., Ltd.), etc.
  • Essina registered trademark
  • SCA40 manufactured by Sekisui Chemical Co., Ltd.
  • ZEONOR registered trademark film
  • a commercial product of a film made of a resin may be used.
  • the cyclic polyolefin resin film may be uniaxially stretched or biaxially stretched.
  • An arbitrary retardation value can be imparted to the cyclic polyolefin-based resin film by stretching. Stretching is usually performed continuously while unwinding the film roll, and is stretched in the heating furnace in the roll traveling direction, the direction perpendicular to the traveling direction, or both.
  • the temperature of the heating furnace is usually in the range from the vicinity of the glass transition temperature of the cyclic polyolefin resin to the glass transition temperature + 100 ° C.
  • the stretching ratio is usually 1.1 to 6 times, preferably 1.1 to 3.5 times in one direction.
  • the cyclic polyolefin resin film generally has poor surface activity
  • surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame (flame) treatment, saponification treatment is performed on the surface to be bonded to the polarizing film.
  • plasma treatment and corona treatment that can be performed relatively easily are preferable.
  • Examples of the cellulose acetate-based resin film include commercially available products such as Fujitac (registered trademark) TD80 (manufactured by Fuji Film Co., Ltd.), Fujitac (registered trademark) TD80UF (manufactured by Fuji Film Co., Ltd.), and Fujitac (registered trademark).
  • TD80UZ Fluji Film Co., Ltd.
  • Fujitac registered trademark
  • TD40UZ Fujiji Film Co., Ltd.
  • KC8UX2M Konica Minolta Opto Co., Ltd.
  • KC4UY Konica Minolta Opto Co., Ltd.
  • a liquid crystal layer or the like may be formed on the surface of the cellulose acetate-based resin film in order to improve viewing angle characteristics. Moreover, in order to provide a phase difference, what stretched the cellulose acetate type-resin film may be used.
  • the cellulose acetate-based resin film is usually subjected to a saponification treatment in order to improve the adhesiveness with the polarizing film.
  • a saponification treatment a method of immersing in an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide can be employed.
  • Optical layers such as a hard coat layer, an antiglare layer, and an antireflection layer can be formed on the surfaces of the protective films 109 and 110 as described above.
  • the method for forming these optical layers on the surface of the protective film is not particularly limited, and a known method can be used.
  • the thickness of the protective films 109 and 110 is preferably as thin as possible from the request for thinning, preferably 88 ⁇ m or less, and more preferably 48 ⁇ m or less. On the other hand, if it is too thin, the strength is lowered and the processability is poor, and therefore it is preferably 5 ⁇ m or more.
  • the upper protective film 110 and the lower protective film 109 may be the same or different.
  • the protective films 109 and 110 and the polarizing film 101 are bonded through, for example, an unillustrated adhesive layer or pressure-sensitive adhesive layer.
  • the bonding surfaces of the protective films 109 and 110 may be subjected to easy adhesion treatment such as corona discharge treatment and primer treatment (formation of a primer layer) prior to bonding with an adhesive or a pressure-sensitive adhesive.
  • Adhesive layer The adhesive used for bonding the protective films 109 and 110 and the polarizing film 101 is, for example, an aqueous adhesive using a polyvinyl alcohol resin aqueous solution, an aqueous two-component urethane emulsion adhesive, or the like. Is mentioned.
  • a polyvinyl alcohol resin aqueous solution is suitably used as an aqueous adhesive for bonding to the polarizing film 101.
  • Polyvinyl alcohol resins used as adhesives include vinyl alcohol homopolymers obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as other single quantities copolymerizable with vinyl acetate. And vinyl alcohol copolymers obtained by saponifying the copolymer with the polymer, and modified polyvinyl alcohol polymers obtained by partially modifying the hydroxyl groups.
  • a polyhydric aldehyde, a water-soluble epoxy compound, a melamine compound, a zirconia compound, a zinc compound, or the like may be added as an additive to the water-based adhesive. When such a water-based adhesive is used, the adhesive layer obtained therefrom is usually 1 ⁇ m or less.
  • the method of bonding the polarizing film 101 and the protective films 109 and 110 using an aqueous adhesive is not particularly limited.
  • the adhesive is uniformly applied to the surfaces of the polarizing film 101 and / or the protective films 109 and 110.
  • coating surface, bonding with a roll etc., and drying is mentioned.
  • the adhesive is applied at a temperature of 15 to 40 ° C., and the laminating temperature is usually in the range of 15 to 30 ° C.
  • the polarizing film 101 and the protective films 109 and 110 are bonded, and then dried to remove water contained in the water-based adhesive.
  • the temperature of the drying furnace is preferably 30 ° C to 90 ° C. When the temperature is lower than 30 ° C., the adhesive surface between the polarizing film 101 and the protective films 109 and 110 tends to be easily peeled off. If it is 90 ° C. or higher, the optical performance may be deteriorated by heat.
  • the drying time can be 10 to 1000 seconds, and particularly from the viewpoint of productivity, it is preferably 60 to 750 seconds, and more preferably 150 to 600 seconds.
  • the temperature at the time of curing is generally set lower than the temperature adopted at the time of drying.
  • a photocurable adhesive can also be used as an adhesive when the polarizing film 101 and the protective films 109 and 110 are bonded together.
  • the photocurable adhesive include a mixture of a photocurable epoxy resin and a photocationic polymerization initiator.
  • a conventionally known method can be used as a method of applying an adhesive to the polarizing film 101 or the protective films 109 and 110.
  • a casting method a Mayer bar coating method, a gravure coating method, a comma coater method, a doctor plate method, a die coating method, a dip coating method, a spraying method and the like can be mentioned.
  • the polarizing film 101 or the protective films 109 and 110 that are the objects to be coated are moved in a substantially vertical direction, a substantially horizontal direction, or an oblique direction between them, and an adhesive is allowed to flow onto the surface. It is a method of spreading.
  • the polarizing film 101 and the protective film 109, 110 are bonded together by sandwiching them with a nip roll or the like through the adhesive application surface.
  • an adhesive is dropped between the polarizing film 101 and the protective films 109 and 110 in a state where the polarizing film 601 and the protective films 109 and 110 are overlapped, and then the laminated body is pressed uniformly with a roll or the like.
  • a method of spreading out can also be suitably used. In this case, a metal, rubber, or the like can be used as the material of the roll.
  • a method of passing the laminate between the rolls and pressurizing and spreading is preferably employed.
  • these rolls may be made of the same material or different materials.
  • the thickness of the adhesive layer after being bonded using the nip roll or the like before drying or curing is preferably 5 ⁇ m or less and 0.01 ⁇ m or more.
  • the surface of the polarizing film 101 and / or the protective film 109, 110 is appropriately subjected to a surface treatment such as a plasma treatment, a corona treatment, an ultraviolet irradiation treatment, a flame (flame) treatment, or a saponification treatment.
  • a surface treatment such as a plasma treatment, a corona treatment, an ultraviolet irradiation treatment, a flame (flame) treatment, or a saponification treatment.
  • a surface treatment such as a plasma treatment, a corona treatment, an ultraviolet irradiation treatment, a flame (flame) treatment, or a saponification treatment.
  • a saponification treatment include a method of immersing in an aqueous alkali solution such as sodium hydroxide or potassium hydroxide.
  • the photocurable adhesive is cured by irradiating active energy rays after the polarizing film 101 and the protective films 109 and 110 are joined.
  • the light source of the active energy ray is not particularly limited, but an active energy ray having a light emission distribution at a wavelength of 400 nm or less is preferable.
  • the low pressure mercury lamp, the medium pressure mercury lamp, the high pressure mercury lamp, the ultrahigh pressure mercury lamp, the chemical lamp, and the black light lamp A microwave excitation mercury lamp, a metal halide lamp and the like are preferably used.
  • the light irradiation intensity to the photocurable adhesive is appropriately determined depending on the composition of the photocurable adhesive and is not particularly limited, but the irradiation intensity in the wavelength region effective for activating the polymerization initiator is 0.1 to 6000 mW / it is preferable that the cm 2.
  • the irradiation intensity is 0.1 mW / cm 2 or more, the reaction time does not become too long, and when it is 6000 mW / cm 2 or less, the epoxy is generated by the heat radiated from the light source and the heat generated when the photo-curable adhesive is cured. There is little risk of yellowing of the resin or deterioration of the polarizing film.
  • the light irradiation time to the photocurable adhesive is not particularly limited and is applied according to the photocurable adhesive to be cured, but the integrated light amount expressed as the product of the irradiation intensity and the irradiation time. Is preferably set to 10 to 10,000 mJ / cm 2 . When the cumulative amount of light to the photocurable adhesive is 10 mJ / cm 2 or more, a sufficient amount of active species derived from the polymerization initiator can be generated to allow the curing reaction to proceed more reliably, and at 10,000 mJ / cm 2 or less. In some cases, the irradiation time does not become too long and good productivity can be maintained.
  • the thickness of the adhesive layer after irradiation with active energy rays is usually about 0.001 to 5 ⁇ m, preferably 0.01 ⁇ m or more and 2 ⁇ m or less, more preferably 0.01 ⁇ m or more and 1 ⁇ m or less.
  • the photocurable adhesive When the photocurable adhesive is cured by irradiation with active energy rays, it is cured under conditions that do not deteriorate the functions of the polarizing plate, such as the degree of polarization, the transmittance and the hue of the polarizing film 101, and the transparency of the protective films 109 and 110. It is preferable to carry out.
  • Adhesive layer The adhesive used for bonding the protective films 109 and 110 and the polarizing film 101 is usually based on an acrylic resin, a styrene resin, a silicone resin, etc., and an isocyanate compound. And a composition to which a crosslinking agent such as an epoxy compound or an aziridine compound is added.
  • the thickness of the pressure-sensitive adhesive layer is preferably 1 to 40 ⁇ m, but it is preferably thinly applied as long as the workability and durability characteristics are not impaired, and more preferably 3 to 25 ⁇ m. When the thickness is 3 to 25 ⁇ m, it has good processability and is also suitable for suppressing the dimensional change of the polarizing film. When the pressure-sensitive adhesive layer is less than 1 ⁇ m, the tackiness is lowered, and when it exceeds 40 ⁇ m, problems such as the pressure-sensitive adhesive protruding easily occur.
  • the protective film 109 and 110 may be bonded to the polarizing film 101 after providing an adhesive layer on the surface of the protective film 109 or 110. After providing the pressure-sensitive adhesive layer on the surface, protective films 109 and 110 may be bonded thereto.
  • the method for forming the pressure-sensitive adhesive layer is not particularly limited, and a solution containing each component including the above-mentioned base polymer is applied to the protective film 109, 110 surface or the polarizing film 101 surface and dried.
  • the protective films 109 and 110 and the polarizing film 101 may be bonded together, or after forming the pressure-sensitive adhesive layer on the separator, the surface is transferred to the protective film 109 or 110 surface or the polarizing film 101 surface. And may be laminated.
  • an adhesion treatment is performed on the surface of the protective film 109, 110 or the polarizing film 101, or one or both of the pressure-sensitive adhesive layer, if necessary. Corona treatment or the like may be performed.
  • the light diffusing polarizing plate of the present embodiment having the above-described configuration can be used by stacking other optical layers in practical use.
  • the protective films 109 and 110 may have the functions of these optical layers.
  • other optical layers include a reflective polarizing film that transmits certain types of polarized light and reflects polarized light that exhibits the opposite properties, a film with an antiglare function having an uneven shape on the surface, and a surface antireflection function. Examples thereof include an attached film, a reflective film having a reflective function on the surface, a transflective film having both a reflective function and a transmissive function, and a viewing angle compensation film.
  • the viewing angle compensation film examples include an optical compensation film coated with a liquid crystal compound on the surface of the substrate and oriented, a retardation film made of a polycarbonate resin, and a retardation film made of a cyclic polyolefin resin.
  • the light diffusing layer 106 of the diffusing film 102 and these optical layers are formed in the same manner through the same adhesive layer or pressure-sensitive adhesive layer as described in the bonding of the protective films 109 and 110 and the polarizing film 101 described above. Can be pasted together.
  • FIG. 7 is a schematic cross-sectional view showing the light diffusing polarizing plate of the second embodiment.
  • the light diffusing polarizing plate 300 includes a polarizing film 101, a light diffusing film 102 is laminated on one surface of the polarizing film 101, and a lower protective film on the other surface of the polarizing film 101. 109 are stacked.
  • the light diffusion film 102 includes a base film 105 and a light diffusion layer 106. Since the base film 105 is laminated immediately above the polarizing film 101, it also functions as an upper protective film.
  • at least one of the base film 105 and the lower protective film 109 is a light diffusing agent-containing film, and the base film 105 is preferably a light diffusing agent-containing film.
  • the light diffusing polarizing plate 300 of this embodiment differs from the light diffusing polarizing plate 100 of the first embodiment only in that the base film 105 of the light diffusing film 102 also serves as the upper protective film. Since the detailed configurations of the film 101, the lower protective film 109, and the light diffusion film 102 are as described in the first embodiment, the same members are denoted by the same reference numerals and description thereof is omitted.
  • the light diffusing polarizing plate having the above-described configuration is preferably used as a polarizing plate on the viewing side of a liquid crystal display device, and typically a liquid crystal display so that the light diffusing film 102 is positioned on the viewing side from the polarizing sheet 101. Built into the device.
  • the liquid crystal display device of the present invention comprises a backlight device, a light diffusion means, a backlight side polarizing plate, a liquid crystal cell, and the light diffusing polarizing plate of the present invention in this order.
  • FIG. 8 is a schematic cross-sectional view showing a preferred example of the liquid crystal display device of the present invention.
  • the liquid crystal display device 400 of FIG. 8 is a normally white mode TN liquid crystal display device, and includes a backlight device 402, a light diffusion means 403, a backlight side polarizing plate 404, and a pair of transparent substrates 411a and 411b.
  • the backlight side polarizing plate 404 and the light diffusing polarizing plate 405 are disposed so that their transmission axes have a crossed Nicols relationship.
  • the adhesive layer or the adhesive layer is bonded to the protective films 109 and 110 and the polarizing film 101 in the above.
  • the same adhesive layer as described for the adhesive layer or adhesive layer used for the combination can be used, or a light diffusing adhesive can be prepared by further adding a light diffusing agent to the above adhesive layer.
  • An agent layer can also be used.
  • an adhesive layer having light diffusibility can be used.
  • the backlight device 402 is a direct-type backlight device including a rectangular parallelepiped case 421 having an upper surface opening and a plurality of cold cathode tubes 422 as linear light sources arranged in parallel in the case 421.
  • the light diffusion means 403 is provided on the light diffusion plate 403a disposed on the backlight device 402 and on the front side of the light diffusion plate 403a (between the light diffusion plate 403a and the backlight side polarizing plate 404). And an optical deflection plate (prism sheet) 403b.
  • the light emitted from the backlight device 402 is diffused by the light diffusing plate 403a of the light diffusing means 403, and then the light incident surface of the liquid crystal cell 401 by the light deflecting plate 403b.
  • Predetermined directivity with respect to the normal direction is given.
  • the directivity with respect to the normal direction is set higher than that of the conventional apparatus.
  • the light having a predetermined directivity is polarized by the backlight side polarizing plate 404 and enters the liquid crystal cell 401.
  • Light incident on the liquid crystal cell 401 is emitted from the liquid crystal cell 401 after the polarization state is controlled by the liquid crystal layer 412.
  • the light emitted from the liquid crystal cell 401 is diffused by the light diffusing polarizing plate 405.
  • the directivity in the normal direction of the light incident on the liquid crystal cell 401 in the light diffusing unit 403 is made higher than that in the conventional case, that is, the incident light to the liquid crystal cell 401 is reduced. It is assumed that the light is more concentrated than before, and is further diffused by the light diffusing polarizing plate 405. As a result, image quality such as color reproducibility superior to that of the conventional apparatus can be obtained.
  • the liquid crystal cell 401 includes a pair of transparent substrates 411a and 411b arranged to face each other with a predetermined distance by a spacer, and a liquid crystal layer 412 formed by sealing liquid crystal between the pair of transparent substrates 411a and 411b.
  • the pair of transparent substrates 411a and 411b are each formed by laminating a transparent electrode and an alignment film, and the liquid crystal is aligned by applying a voltage based on display data between the transparent electrodes.
  • the display method of the liquid crystal cell 401 is the TN method in the above example, but a display method such as an IPS method or a VA method may also be adopted.
  • the backlight device 402 includes a rectangular parallelepiped case 421 having an upper surface opening, and a plurality of cold cathode tubes 422 as linear light sources arranged in parallel in the case 421.
  • the case 421 is formed from a resin material or a metal material, and at least the inner peripheral surface of the case 421 may be white or silver from the viewpoint of reflecting the light emitted from the cold cathode tube 422 on the inner peripheral surface of the case 421. desirable.
  • LEDs of various shapes such as a linear shape can be used in addition to a cold cathode tube.
  • the number of the linear light sources to be arranged is not particularly limited, but the distance between the centers of the adjacent linear light sources is in the range of 15 mm to 150 mm from the viewpoint of suppressing luminance unevenness on the light emitting surface. It is preferable.
  • the backlight device 402 used in the present embodiment is not limited to the direct type shown in FIG. 5, but is a sidelight type in which a linear light source or a point light source is arranged on the side surface of the light guide plate, or Various types such as a planar light source type can be used.
  • the light diffusing unit 403 includes a light diffusing plate 403a disposed on the backlight device 402 and a front side of the light diffusing plate 403a (the light diffusing plate 403a and the backlight side polarizing plate 404 And a light deflector plate (prism sheet) 403b provided between the two.
  • the light diffusing plate 403 a can be a film or sheet in which a light diffusing agent 440 is dispersed and mixed with a base material 430.
  • polycarbonate resin methacrylic resin, methyl methacrylate-styrene copolymer resin, acrylonitrile-styrene copolymer resin, methacrylic acid-styrene copolymer resin, polystyrene resin, polyvinyl chloride resin
  • Polyolefin resins such as polypropylene and polymethylpentene, cyclic polyolefin resins, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyamide resins, polyarylate resins, and polyimide resins can be used.
  • the light diffusing agent 440 mixed and dispersed in the base material 430 is not particularly limited as long as it is a fine particle made of a material having a refractive index different from that of the material to be the base material 430.
  • Organic fine particles consisting of various acrylic resins, melamine resins, polyethylene resins, polystyrene resins, organic silicone resins, acrylic-styrene copolymer resins, etc., and calcium carbonate, silica, aluminum oxide, barium carbonate, barium sulfate, titanium oxide, Examples include inorganic fine particles made of glass.
  • the weight average particle diameter of the light diffusing agent 440 is preferably in the range of 0.5 to 30 ⁇ m.
  • the light diffusing agent 440 may have a spherical shape, a flat shape, a plate shape, a needle shape, or the like, but is preferably a spherical shape.
  • the light deflection plate (prism sheet) 403b has a flat surface on the light incident surface side (backlight device 402 side) and a tapered cross section on the light emission surface (surface facing the backlight side polarizing plate 404).
  • the material of the light deflector 403b include polycarbonate resins, ABS resins, methacrylic resins, methyl methacrylate-styrene copolymer resins, polystyrene resins, acrylonitrile-styrene copolymer resins, and polyolefin resins such as polyethylene and polypropylene.
  • Examples thereof include resins.
  • a normal thermoplastic resin molding method can be used, and examples thereof include hot press molding using a mold and extrusion molding.
  • the thickness of the light deflection plate 403b is usually 0.1 to 15 mm, preferably 0.5 to 10 mm.
  • the light diffusing plate 403a and the light deflecting plate 403b may be integrally formed, or may be formed separately and then joined. Further, in the case of separately producing and joining, the light diffusing plate 403a and the light deflecting plate 403b may be contacted via an air layer. Further, the light diffusion plate 403a and the light deflection plate 403b may be arranged apart from each other.
  • the light diffusing means 403 may be provided with a light diffusing function by dispersing and mixing a light diffusing agent 440 on a light deflecting plate 403 b having a light deflecting function.
  • FIG. 11 shows another example of the light diffusion means.
  • the light diffusion means 403 may have two light deflection plates (prism sheets) arranged on the front side of the light diffusion plate 403a.
  • the direction of the ridge line 451 of the linear prism 450 is substantially the same as the transmission axis direction of the backlight side polarizing plate 404.
  • the light deflection plate 403b ′ arranged so as to be parallel to each other and disposed on the front side of the light deflection plate 403b has the direction of the ridge line 451 ′ of the linear prism 450 ′ as the transmission axis direction of the light diffusing polarizing plate 405.
  • the direction of the ridge line 451 ′ of the linear prism 450 ′ of the light deflector 403b ′ is substantially parallel to the transmission axis direction of the backlight side polarizing plate 404, and the linear prism 450 of the light deflector 403b. It is also possible to arrange the ridge line 451 so that the direction of the ridge line 451 is substantially parallel to the transmission axis direction of the light diffusing polarizing plate 405.
  • FIG. 12 shows an example of a method of measuring the luminance value in the direction of 70 ° with respect to the normal line of the light incident surface of the liquid crystal cell with respect to the light diffusion means.
  • the light distribution characteristic of the light that has passed through the light diffusing means 403 is that the luminance value in the direction inclined by 70 ° from the normal direction of the light incident surface of the liquid crystal cell 401 is the front luminance value, that is, the light incident surface of the liquid crystal cell 401. It is preferable that the luminance value is 20% or less with respect to the luminance value in the normal direction, and the emitted light from the light diffusion means 403 includes non-parallel light.
  • a more preferable light distribution characteristic is to prevent light exceeding 60 ° from the normal line of the light incident surface of the liquid crystal cell 401.
  • the back surface of the light diffusing means 403 and the light incident surface of the liquid crystal cell 401 are arranged in parallel, so that the 70 ° direction of the light incident surface of the liquid crystal cell 401 is normal.
  • the luminance value is a normal line to the xy plane when the longitudinal direction of the light diffusing unit 403 is the x direction and the plane parallel to the back surface of the light diffusing unit 403 is the xy plane.
  • the luminance value is in the direction of 70 ° with respect to the z axis, and preferably the luminance value in the direction in which the angle formed with the z axis on the xz plane is 70 °.
  • the shape of the linear prism 450 (and / or the linear prism 450 ') having a triangular cross section of the light deflection plate 403b may be adjusted.
  • the apex angle ⁇ (see FIGS. 9 and 10) of the linear prisms 450 and 450 ′ is preferably in the range of 60 to 120 °, more preferably 90 to 110 °.
  • an equal side and an unequal side can be arbitrary, but an isosceles triangle is preferable when concentrating in the normal direction of the liquid crystal cell 401 (front direction of the liquid crystal display device).
  • the prism surface composed of linear prisms is arranged sequentially so that the bases corresponding to the apex angles of the triangles are adjacent to each other, and a plurality of linear prisms are arranged so as to be substantially parallel to each other. Is preferred.
  • the V-shaped grooves formed by the apexes of the linear prisms and the adjacent linear prisms may be curved as long as the light collecting ability is not significantly reduced.
  • the distance between the ridgelines of the linear prism (distance d shown in FIGS. 9 and 10) is usually in the range of 10 ⁇ m to 500 ⁇ m, and preferably in the range of 30 ⁇ m to 200 ⁇ m.
  • FIG. 12 is a diagram for explaining the definition of non-parallel light.
  • non-parallel light means that light emitted from a circle having a diameter of 1 cm on the exit surface of the light diffusing means 403 is parallel to the exit surface 1 m away from the normal direction of the exit surface.
  • the light When viewed as a projection image on a simple observation surface, the light has an emission characteristic such that the minimum half-value width of the in-plane luminance distribution of the projection image is 30 cm or more.
  • Backlight side polarizing plate As the backlight-side polarizing plate 404, a polarizing film in which a protective film is bonded to one side or both sides can be usually used. As a polarizing film and a protective film, what was mentioned above about the light diffusable polarizing plate can be used.
  • FIG. 14 is a schematic cross-sectional view showing another preferred example of the liquid crystal display device of the present invention.
  • the liquid crystal display device of this embodiment can include a retardation plate 406 as shown in FIG.
  • the phase difference plate 406 is disposed between the backlight side polarizing plate 404 and the liquid crystal cell 401.
  • This phase difference plate 406 has a substantially zero phase difference in a direction perpendicular to the surface of the liquid crystal cell 401, has no optical effect from the front, and has a phase difference when viewed from an oblique direction. It is expressed and compensates for the phase difference generated in the liquid crystal cell 401.
  • the retardation plate 406 can be disposed between the backlight side polarizing plate 404 and the liquid crystal cell 401, or between the light diffusing polarizing plate 405 and the liquid crystal cell 401, or both.
  • the retardation film 406 can be laminated on the protective film of the backlight-side polarizing plate 404, or can be laminated directly on the polarizing film so as to function as a protective film. The same applies to the light diffusing polarizing plate 405.
  • phase difference plate 406 for example, a polycarbonate resin or a cyclic olefin polymer resin is used as a film, and this film is further biaxially stretched, or a liquid crystalline monomer is applied to the film, and its molecular arrangement is changed by a photopolymerization reaction. Immobilized ones are listed.
  • the phase difference plate 406 optically compensates for the alignment of the liquid crystal, and therefore has a refractive index characteristic opposite to that of the liquid crystal alignment.
  • a TN mode liquid crystal cell for example, “WV film” (manufactured by FUJIFILM Corporation)
  • STN mode liquid crystal display cell for example, “LC film” (manufactured by Nippon Oil Corporation)
  • LC film manufactured by Nippon Oil Corporation
  • IPS mode liquid crystal display cells for example, a biaxial retardation film
  • VA mode liquid crystal display cells for example, a retardation plate or a biaxial retardation film combining a A plate and a C plate
  • a ⁇ cell for the mode liquid crystal display cell, for example, “OCB WV film” (manufactured by FUJIFILM Corporation) can be suitably used.
  • the relative scattered light intensity of the light diffusing polarizing plate, the haze, the thickness of the light diffusing layer of the light diffusing film, the bending strength of the light diffusing film, the haze of the light diffusing agent-containing film, and the light used The measuring method of the weight average particle diameter of the diffusing agent is as follows.
  • a “3292 03 optical power sensor” manufactured by Yokogawa Electric Corporation and a “3292 optical power meter” manufactured by the same company were used.
  • a light source for irradiating a He—Ne laser was disposed at a position of 430 mm from the glass substrate.
  • the power sensor which is a light receiver, was arranged in a direction A3 inclined by 40 ° from the normal direction on the light diffusion layer side of the sample at a position 280 mm from the emission point of the laser beam.
  • (C) Thickness of the light diffusion layer The thickness of the light diffusion film is measured using DIGIMICRO MH-15 (main body) and ZC-101 (counter) manufactured by NIKON, and the thickness of the base sheet is subtracted from the measurement layer thickness. Thus, the thickness of the light diffusion layer was measured.
  • the resin supplied to the feed block from the first extruder becomes a light diffusion layer (intermediate layer), and the resin supplied to the feed block from the second extruder becomes a transparent resin layer (surface layer: both sides)
  • Co-extrusion was performed at 265 ° C., and a base film having a three-layer structure having a thickness of 78 ⁇ m (intermediate layer 28 ⁇ m, surface layer 15 ⁇ m ⁇ 2) was produced through a roll unit set at 85 ° C.
  • the obtained base film had a haze of 45%.
  • polystyrene particles having a weight average particle size of 7.2 ⁇ m, a standard deviation of 0.52 ⁇ m, and a refractive index of 1.59 are used as a light diffusing agent with respect to 100 parts by weight of the solid content of the ultraviolet curable resin composition.
  • 10 parts by weight and 5 parts by weight of “Lucirin TPO” (manufactured by BASF, chemical name: 2,4,6-trimethylbenzoyldiphenylphosphine oxide) as a photopolymerization initiator are added, and the solid content is 60% by weight.
  • a coating solution was prepared by diluting with propylene glycol monomethyl ether.
  • This coating solution was applied onto the substrate film prepared in Production Example 1 and dried for 1 minute in a dryer set at 80 ° C.
  • the base film after drying was brought into close contact with the mirror surface of the mirror-finished metal roll produced above with a rubber roll so that the ultraviolet curable resin composition layer was on the roll side.
  • light from a high-pressure mercury lamp having an intensity of 20 mW / cm 2 is irradiated from the base film side so as to be 300 mJ / cm 2 in terms of the amount of h-line conversion, and the ultraviolet curable resin composition layer is cured and flattened.
  • the light-diffusion film which consists of a light-diffusion layer and a base film which have an appropriate surface was obtained.
  • the thickness of the light diffusion layer after curing was 8 ⁇ m.
  • the above-mentioned bending strength test was done about the obtained light-diffusion film. Evaluation was (circle).
  • Production example b A light diffusion film was obtained by the same material and the same method as in Production Example a, except that the base film produced in Production Example 2 was used as the base film. The thickness of the light diffusion layer after curing was 8 ⁇ m. Moreover, the above-mentioned bending strength test was done about the obtained light-diffusion film. Evaluation was (circle).
  • Example 1 A norbornene-based resin film (“ZEONOR FILM” from Nippon Zeon Co., Ltd.) is bonded to both sides of the polarizing film obtained above as a protective film via an ultraviolet curable epoxy adhesive, and one of the protective films The light diffusion film produced in Production Example a is bonded to the surface of the film through an ultraviolet curable epoxy adhesive with the base film side of the light diffusion film as an adhesive surface, and the protective film, polarizing film, protective film, and light from Production Example a The light diffusable polarizing plate of Example 1 with which the diffusion film was laminated
  • Example 2 A norbornene-based resin film (“ZEONOR FILM” from Nippon Zeon Co., Ltd.) is bonded to one side of the polarizing film obtained above as a protective film via an ultraviolet curable epoxy adhesive, and the other side The base film side of the light diffusing film produced in Production Example a is bonded as an adhesive surface via an ultraviolet curable epoxy adhesive, and the protective film, polarizing film, and the light diffusing film of Production Example a are in this order. A laminated light diffusing polarizing plate of Example 2 was obtained.
  • ZONOR FILM from Nippon Zeon Co., Ltd.
  • Comparative Example 1 A norbornene-based resin film (“ZEONOR FILM” from Nippon Zeon Co., Ltd.) is bonded to both sides of the polarizing film obtained above as a protective film via an ultraviolet curable epoxy adhesive, and one of the protective films
  • the light diffusion film produced in Production Example b is bonded to the surface of the film through an ultraviolet curable epoxy adhesive with the base film side of the light diffusion film as an adhesive surface, and a protective film, a polarizing film, a protective film, and the light of Production Example b
  • Comparative Example 2 A norbornene-based resin film (“ZEONOR FILM” from Nippon Zeon Co., Ltd.) is bonded to both sides of the polarizing film obtained above as a protective film via an ultraviolet curable epoxy adhesive, and one of the protective films
  • the light diffusion film produced in Production Example c is bonded to the surface of the film through an ultraviolet curable epoxy adhesive with the base film side of the light diffusion film as an adhesive surface, and a protective film, a polarizing film, a protective film, and the light of Production Example c
  • a liquid crystal display device was produced using the obtained light diffusing polarizing plate, and the image quality was comprehensively evaluated based on the front contrast, the viewing angle, the degree of moire, and the degree of whitishness.
  • a light diffusing plate was arranged on the backlight device of the Panasonic IPS mode 32-inch LCD TV “VIERA TH-32LZ85”, and a plurality of linear prisms having an apex angle of 95 ° were arranged in parallel. Two prism films were used, and these were arranged between the light diffusion plate and the backlight side polarizing plate.
  • one prism film (prism film close to the backlight device) is arranged so that the direction of the ridgeline of the linear prism is substantially parallel to the transmission axis of the backlight side polarizing plate, and the other prism film ( The prism film near the backlight side polarizing plate) was arranged so that the direction of the ridgeline of the linear prism was substantially parallel to the transmission axis of the viewing side polarizing plate (light diffusing polarizing plate) described later.
  • the luminance value in the direction of 70 ° with respect to the normal direction was 10% of the luminance value in the normal direction.
  • the viewing side polarizing plate was peeled off, and the light diffusing polarizing plates of Examples 1 and 2 and Comparative Examples 1 and 2 were bonded to the backlight side polarizing plate so as to be crossed Nicol, and a liquid crystal display device Got.
  • the light diffusion film (Production Example a) used in Examples 1 and 2 is thinner than the light diffusion film (Production Example c) used in Comparative Example 2.
  • Table 1 shows, according to the liquid crystal display device using the light diffusable polarizing plate which concerns on Example 1, 2, a favorable image quality is obtained.
  • the liquid crystal display device using the light diffusing polarizing plate of Comparative Example 2 in which the light diffusing film is thickened to increase the light diffusing property the same image quality can be obtained, but in this case, the light diffusing film is weak against bending. It becomes difficult to handle. Therefore, according to the present invention, it is possible to contribute to the thinning of the liquid crystal display device by thinning the polarizing film while exhibiting good display characteristics, and the mechanical strength is strong and the handling becomes easy.
  • the light diffusing polarizing plate according to the present invention is a polarizing plate provided with a light diffusing function by providing a light diffusing layer, and has a sufficient mechanical strength, so that it is good when incorporated in a liquid crystal display device. Display with high image quality. Therefore, the light diffusing polarizing plate and the liquid crystal display device using the same according to the present invention are suitable for use in mobile phones, personal computer monitors, televisions, liquid crystal projectors, and the like.

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Abstract

La présente invention concerne une plaque de polarisation qui possède une résistance mécanique suffisante et qui remplit une fonction de diffusion de lumière car elle comprend une couche de diffusion de lumière. La plaque de polarisation permet un affichage d'une grande qualité d'image lorsqu'elle est incorporée dans un dispositif d'affichage à cristaux liquides. La présente invention concerne également un dispositif d'affichage à cristaux liquides qui utilise la plaque de polarisation. Selon un mode de réalisation de la présente invention, une plaque de polarisation de diffusion de lumière (100) est obtenue en stratifiant séquentiellement, dans l'ordre suivant, un film de protection (109), un film de polarisation (101), un film de protection (110) et un film de diffusion de lumière (102) qui est obtenu en stratifiant un film de base (105) et une couche de diffusion de lumière (106). Le voile total de la plaque de polarisation de diffusion de lumière (100) se situe entre 20 et 85 % (limites comprises). Le voile interne de la plaque de polarisation de diffusion de lumière (100) se situe entre 20 et 85 % (limites comprises). Le film de protection (109) et/ou le film de protection (110) et/ou le film de base (105) est un film contenant un agent de diffusion de lumière qui contient un agent de diffusion de lumière et a un voile total de 10 à 80 % (limites comprises). Selon un mode de réalisation de la présente invention, un dispositif d'affichage à cristaux liquides utilise la plaque de polarisation de diffusion de lumière (100).
PCT/JP2011/063977 2010-06-24 2011-06-17 Plaque de polarisation de diffusion de lumière et dispositif d'affichage à cristaux liquides WO2011162188A1 (fr)

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WO2020026960A1 (fr) * 2018-07-31 2020-02-06 コニカミノルタ株式会社 Film optique, film protecteur de plaques de polarisation, et plaque de polarisation
CN114600008A (zh) * 2019-10-24 2022-06-07 日东电工株式会社 光扩散薄膜、以及具备光扩散薄膜的偏光板
CN115895007A (zh) * 2022-12-17 2023-04-04 常熟卓辉光电科技股份有限公司 一种新型导光板及其制造方法

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JP6871756B2 (ja) * 2017-02-20 2021-05-12 リンテック株式会社 位置検出機能付き画像表示装置
JP7236801B2 (ja) * 2017-11-09 2023-03-10 恵和株式会社 偏光板用保護シート、偏光板、及び液晶表示装置
JP6711473B1 (ja) * 2018-10-01 2020-06-17 大日本印刷株式会社 透明基材、調光部材

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JP2009210592A (ja) * 2008-02-29 2009-09-17 Sumitomo Chemical Co Ltd 防眩性偏光板およびそれを用いた画像表示装置
JP2009301014A (ja) * 2008-04-03 2009-12-24 Sumitomo Chemical Co Ltd 液晶表示装置

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JP2009210592A (ja) * 2008-02-29 2009-09-17 Sumitomo Chemical Co Ltd 防眩性偏光板およびそれを用いた画像表示装置
JP2009301014A (ja) * 2008-04-03 2009-12-24 Sumitomo Chemical Co Ltd 液晶表示装置

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017117761A (ja) * 2015-12-25 2017-06-29 共同印刷株式会社 有機ｅｌデバイス用吸湿性光散乱シート
WO2020026960A1 (fr) * 2018-07-31 2020-02-06 コニカミノルタ株式会社 Film optique, film protecteur de plaques de polarisation, et plaque de polarisation
CN114600008A (zh) * 2019-10-24 2022-06-07 日东电工株式会社 光扩散薄膜、以及具备光扩散薄膜的偏光板
CN115895007A (zh) * 2022-12-17 2023-04-04 常熟卓辉光电科技股份有限公司 一种新型导光板及其制造方法
CN115895007B (zh) * 2022-12-17 2023-08-08 常熟卓辉光电科技股份有限公司 一种导光板及其制造方法

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