Polarizing plate and image display device

Abstract

To provide a polarizing plate which may contribute to improvement in display characteristics of image display devices.SOLUTION: A polarizing plate according to an embodiment of the present invention comprises a laminated film comprising a base material and a surface-treated layer, and a polarizer provided on the base material side of the laminated film. The polarizing plate has a reflectance of 2% or less, a haze in a range of 1% to 13%, inclusive, and a transmittance of 45.5% or greater on the surface-treated layer side.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a polarizing plate and an image display device. [Background technology]

[0002] Polarizing plates are generally used in image display panels mounted on image display devices. A polarizing plate with a retardation layer, in which a polarizing plate and a retardation plate are integrated, is typically used (see, for example, Patent Document 1). In recent years, electroluminescence (EL) display devices (e.g., organic EL display devices) have rapidly become popular as image display devices (typically, smartphones and televisions), and their applications are expanding. For example, their application to laptop personal computers and tablet terminals is being considered. Furthermore, as applications expand, excellent display characteristics are required in all situations. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3325560 Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above, a main object of the present invention is to provide a polarizing plate that can contribute to improving the display characteristics of an image display device. [Means for solving the problem]

[0005] According to an embodiment of the present invention, there is provided a polarizing plate for use in an organic electroluminescence (EL) panel, comprising a laminate film having a substrate and a surface treatment layer, and a polarizer disposed on the substrate side of the laminate film, the polarizing plate having a reflectance of 2% or less on the surface treatment layer side, a haze of 1% to 13%, and a transmittance of 45.5% or more. In one embodiment, the surface treatment layer includes a first layer containing a resin component and hollow particles, and the first layer contains 11 parts by weight or more of the hollow particles per 100 parts by weight of the resin component. In one embodiment, the surface treatment layer includes a first layer containing a resin component and hollow particles, and the first layer contains 40 parts by weight or less of the hollow particles per 100 parts by weight of the resin component. In one embodiment, the polarizing plate further includes a retardation layer, and the in-plane retardation Re(550) of the retardation layer is 100 nm to 190 nm. According to another embodiment of the present invention, there is provided an image display device, which includes an image display panel body and the above-described polarizing plate disposed on the viewer side of the image display panel body. In one embodiment, the polarizing plate is located on the outermost surface on the viewing side. [Effects of the Invention]

[0006] According to the embodiments of the present invention, excellent display characteristics can be achieved. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic cross-sectional view showing the general configuration of a polarizing plate according to one embodiment of the present invention. [Figure 2] 1 is a schematic cross-sectional view showing an organic EL panel and a polarizing plate disposed on the organic EL panel in an organic EL display device according to one embodiment of the present invention. [Figure 3] FIG. 10 is a diagram for explaining a method for evaluating image sticking. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. In addition, in order to clarify the description, the drawings may show the width, thickness, shape, etc. of each part more schematically than in the embodiments, but these are merely examples and do not limit the interpretation of the present invention.

[0009] (Definition of terms and symbols) The definitions of terms and symbols used in this specification are as follows. (1) Refractive index (nx, ny, nz) "nx" is the refractive index in the direction in which the in-plane refractive index is greatest (i.e., the slow axis direction), "ny" is the refractive index in the direction perpendicular to the slow axis in the plane (i.e., the fast axis direction), and "nz" is the refractive index in the thickness direction. (2) In-plane phase difference (Re) "Re(λ)" is the in-plane retardation measured with light of wavelength λ nm at 23°C. For example, "Re(550)" is the in-plane retardation measured with light of wavelength 550 nm at 23°C. Re(λ) is calculated by the formula: Re(λ)=(nx-ny)×d, where d (nm) is the thickness of the layer (film). (3) Retardation in the thickness direction (Rth) "Rth(λ)" is the retardation in the thickness direction measured with light of wavelength λ nm at 23°C. For example, "Rth(550)" is the retardation in the thickness direction measured with light of wavelength 550 nm at 23°C. Rth(λ) is calculated by the formula: Rth(λ) = (nx - nz) × d, where d (nm) is the thickness of the layer (film).

[0010] 1 is a schematic cross-sectional view showing the general configuration of a polarizing plate according to one embodiment of the present invention. Polarizing plate (typically, a circular polarizing plate) 100 has a polarizer 10, a laminate film 20 arranged on one side of polarizer 10, and a protective layer 30, a retardation layer (typically, a λ / 4 plate) 40, and a pressure-sensitive adhesive layer 50 arranged on the other side of polarizer 10. Laminate film 20 includes a substrate 21 and a surface treatment layer 22 formed on substrate 21, and substrate 21 can function as a protective layer for polarizer 10. Protective layer 30 may be omitted, in which case retardation layer 40 can function as a protective layer for the polarizer.

[0011] The components constituting the polarizing plate can be laminated via any appropriate adhesive layer (not shown), for example, while being transported by a roll. Specific examples of the adhesive layer include an adhesive layer and a pressure-sensitive adhesive layer. For example, the laminated film 20 and the protective layer 30 are attached to the polarizer 10 via an adhesive layer (preferably using an active energy ray-curable adhesive). The thickness of the adhesive layer is preferably 0.4 μm or more, more preferably 0.4 μm to 3.0 μm, and even more preferably 0.6 μm to 2.0 μm. For example, the retardation layer 40 is attached to the protective layer 30 via an adhesive layer. The thickness of the adhesive layer disposed between the protective layer 30 and the retardation layer 40 is, for example, 5 μm to 15 μm.

[0012] In the polarizing plate 100, a pressure-sensitive adhesive layer 50 is provided on the side of the polarizer 10 where the laminate film 20 is not disposed. The pressure-sensitive adhesive layer 50 enables the polarizing plate 100 to be attached to, for example, an image display panel included in an image display device. The thickness of the pressure-sensitive adhesive layer 50 is, for example, 10 μm to 20 μm. In practice, a release liner is attached to the surface of the pressure-sensitive adhesive layer 50. The release liner can be temporarily attached until the polarizing plate is ready for use. The use of the release liner protects the pressure-sensitive adhesive layer 50 and enables the polarizing plate to be formed into a roll, for example.

[0013] The polarizing plate may be in a long shape or a sheet shape. Here, "long" refers to an elongated shape in which the length is sufficiently longer than the width, for example, 10 times or more, preferably 20 times or more, the length than the width. A long polarizing plate can be wound into a roll.

[0014] FIG. 2 is a schematic diagram illustrating the overall configuration of an image display device according to one embodiment of the present invention, taking an organic EL display device as an example. Specifically, it is a schematic cross-sectional view illustrating an organic EL panel and a polarizer disposed thereon in an organic EL display device according to one embodiment of the present invention. In an organic EL panel 200, a polarizer 100 is disposed on the viewing side, and a polarizer 10 is disposed closer to an organic EL panel body 70 than a laminated film 20. Specifically, the polarizer 100 is attached to the organic EL panel body 70 with an adhesive layer 50. The organic EL panel body 70 includes a substrate 71 and an upper structure layer 72 including a circuit layer including thin film transistors (TFTs) and the like, an organic light-emitting diode (OLED), and a sealing film for sealing the OLED. In one embodiment, a surface treatment layer 22 of the laminated film 20 is located on the outermost surface of the image display device. Specifically, in the image display device, no protective material such as a glass plate is disposed on the polarizer 100 (surface treatment layer 22).

[0015] The transmittance of the polarizing plate is preferably greater than 45.0%, more preferably 45.5% or more, and even more preferably 46.0% or more. Such a polarizing plate can suppress the luminescence intensity of the image display panel, allowing the image display device to be used for long periods of time. Specifically, it can prevent the problem of screen burn-in caused by long-term image display. Here, the transmittance of the polarizing plate refers to the transmittance of the laminated portion excluding the retardation layer. Specifically, it refers to the transmittance of the laminated portion of the laminated film and polarizer, or the laminated portion of the laminated film, polarizer, and protective layer.

[0016] [Polarizer] The polarizer is typically a resin film containing a dichroic substance (e.g., iodine). Examples of the resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified ethylene-vinyl acetate copolymer films.

[0017] The thickness of the polarizer is preferably 18 μm or less, more preferably 15 μm or less, and even more preferably 12 μm or less, while the thickness of the polarizer is preferably 1 μm or more.

[0018] The polarizer preferably exhibits absorption dichroism at any wavelength between 380 nm and 780 nm. The single transmittance of the polarizer is, for example, 41.5% to 47.0%, preferably 42.0% to 47.0%, and more preferably 44.5% to 47.0%. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and even more preferably 99.9% or more. Here, the single transmittance of the polarizer is a value measured using a laminate of a laminate film and a polarizer, or a laminate of a laminate film, a polarizer, and a protective layer as the measurement object.

[0019] The polarizer can be produced by any appropriate method. Specifically, the polarizer may be produced from a single-layer resin film or a laminate of two or more layers.

[0020] A method for producing a polarizer from the above-mentioned single-layer resin film typically includes subjecting the resin film to a dyeing treatment with a dichroic substance such as iodine or a dichroic dye and a stretching treatment. Examples of the resin film that can be used include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified ethylene-vinyl acetate copolymer films. This method may further include insolubilization treatment, swelling treatment, crosslinking treatment, etc. Since such production methods are well known and commonly used in the art, detailed description thereof will be omitted.

[0021] A polarizer obtained using the laminate can be produced, for example, using a laminate of a resin substrate and a resin film or resin layer (typically, a PVA-based resin layer). Specifically, a PVA-based resin solution is applied to a resin substrate and dried to form a PVA-based resin layer on the resin substrate, thereby obtaining a laminate of the resin substrate and the PVA-based resin layer; and the laminate is stretched and dyed to convert the PVA-based resin layer into a polarizer. In this embodiment, a PVA-based resin layer containing a halide and a PVA-based resin is preferably formed on one side of the resin substrate. The stretching typically involves immersing the laminate in an aqueous boric acid solution and stretching it. Furthermore, the stretching may optionally further include in-air stretching the laminate at a high temperature (e.g., 95°C or higher) before stretching in the aqueous boric acid solution. In addition, in this embodiment, the laminate is preferably subjected to a drying shrinkage treatment in which the laminate is heated while being transported in the longitudinal direction, thereby shrinking the laminate by 2% or more in the width direction. Typically, the manufacturing method of this embodiment involves subjecting a laminate to an in-air auxiliary stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment in this order. By introducing the auxiliary stretching treatment, it is possible to increase the crystallinity of PVA, even when PVA is coated on a thermoplastic resin, thereby achieving high optical properties. Furthermore, by simultaneously increasing the orientation of PVA in advance, problems such as a decrease in orientation or dissolution of PVA when immersed in water during the subsequent dyeing or stretching process can be prevented, thereby achieving high optical properties. Furthermore, when the PVA-based resin layer is immersed in a liquid, the PVA molecular orientation disorder and decrease in orientation can be suppressed compared to when the PVA-based resin layer does not contain a halide, thereby achieving high optical properties. Furthermore, by shrinking the laminate in the width direction by a drying shrinkage treatment, high optical properties can be achieved. A polarizing plate can be obtained by laminating a protective layer on the peeled surface of the obtained resin substrate / polarizer laminate after peeling the resin substrate, or on the surface opposite to the peeled surface. Details of such a method for manufacturing a polarizer are described in, for example, JP 2012-73580 A and Japanese Patent No. 6470455. The entire disclosures of these publications are incorporated herein by reference.

[0022] [Protective layer] The protective layer may be formed of any suitable film that can be used as a protective layer for a polarizer. Specific examples of materials that serve as the main component of the film include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, polysulfone-based, polystyrene-based, cycloolefin-based resins such as polynorbornene, polyolefin-based, (meth)acrylic, and acetate-based resins.

[0023] The thickness of the protective layer is preferably 5 μm to 80 μm, more preferably 10 μm to 40 μm, and even more preferably 15 μm to 35 μm.

[0024] In one embodiment, the protective layer 30 disposed on the side of the polarizer 30 where the laminate film 20 is not disposed is preferably optically isotropic. In this specification, "optically isotropic" means that the in-plane retardation Re(550) is 0 nm to 10 nm and the retardation in the thickness direction Rth(550) is -10 nm to +10 nm.

[0025] [Laminated film] The laminated film has a substrate and a surface treatment layer formed on the substrate. The substrate can function as a protective layer for the polarizer, and details thereof are as described above. The polarizing plate according to an embodiment of the present invention is typically placed on the viewing side of an image display device, and the laminated film is placed on the viewing side. In one embodiment, the surface treatment layer of the laminated film is located on the outermost surface of the image display device. Therefore, it is preferable that a surface treatment layer is formed on the substrate (protective layer on the viewing side). Examples of surface treatments include hard coat (HC) treatment, anti-reflection treatment, anti-sticking treatment, anti-glare treatment, and anti-fouling treatment.

[0026] The haze of the surface-treated layer side of the laminate film is preferably 1% or more, more preferably 1.5% or more, and even more preferably 2% or more. Such a laminate film can suppress the occurrence of moire. Moire is a phenomenon in which light interferes according to wavelength, causing a rainbow pattern to appear on the screen surface. The larger the screen, the more easily the moire tends to be visible. On the other hand, the haze of the surface-treated layer side of the laminate film is preferably 13% or less, more preferably 10% or less, and even more preferably 7% or less. Such a laminate film can suppress the occurrence of white blur, in which the screen surface appears white and blurred. White blur tends to be easily visible in a bright room environment.

[0027] The reflectance of the surface treatment layer side of the laminate film is preferably 2% or less, more preferably 1.6% or less. Such a laminate film can prevent images from being reflected on the screen due to external light such as fluorescent lamps or sunlight, which reduces visibility. Such reflections tend to be more visible in outdoor environments.

[0028] In one embodiment, the surface treatment layer has an antiglare layer and an antireflection layer in this order from the substrate side. The antiglare layer typically contains a resin and a filler. Specifically, the antiglare property can be obtained by incorporating a filler into the resin to create a fine uneven shape on the surface of the resulting layer (antiglare layer).

[0029] For example, an antiglare layer can be typically obtained by applying an antiglare layer-forming material to the substrate and drying and curing the resulting coating film. The antiglare layer-forming material typically contains a curable compound as a layer-forming component. Examples of the curing mechanism of the curable compound include heat-curing and photo-curing. Examples of the curable compound include monomers, oligomers, and prepolymers. Preferably, a polyfunctional monomer or oligomer is used as the curable compound. Examples of the polyfunctional monomer or oligomer include a monomer or oligomer having two or more (meth)acryloyl groups, a urethane (meth)acrylate or a urethane (meth)acrylate oligomer, an epoxy-based monomer or oligomer, and a silicone-based monomer or oligomer.

[0030] The refractive index of the filler is, for example, 1.3 or more and 1.8 or less, and preferably 1.4 or more and 1.6 or less.

[0031] The filler may be inorganic particles, organic particles, or a combination of inorganic and organic particles. Examples of inorganic particles include silicon oxide particles, titanium oxide particles, aluminum oxide particles, zinc oxide particles, tin oxide particles, calcium carbonate particles, barium sulfate particles, talc particles, kaolin particles, and calcium sulfate particles. Examples of organic particles include polymethyl methacrylate resin powder (PMMA particles), silicone resin powder, polystyrene resin powder, polycarbonate resin powder, acrylic styrene resin powder, benzoguanamine resin powder, melamine resin powder, polyolefin resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, and polyethylene fluoride resin powder. These may be used alone or in combination of two or more.

[0032] In one embodiment, the content of the filler is, for example, 1 to 3 parts by weight, or 1.5 to 2.5 parts by weight, relative to 100 parts by weight of the resin. In another embodiment, the content of the filler is, for example, 5 to 7.5 parts by weight, or 6 to 17 parts by weight, relative to 100 parts by weight of the resin.

[0033] The thickness of the antiglare layer is preferably 4 μm to 12 μm, more preferably 6 μm to 9 μm. The solvent that can be contained in the antiglare layer-forming material and the method for coating, drying, and curing the antiglare layer-forming material may be the same as those for the coating liquid for forming an antireflection layer described below.

[0034] The antireflection layer can reduce reflection on the surface of the antiglare layer. The antireflection layer can be obtained, for example, by applying a coating liquid for forming an antireflection layer onto the antiglare layer, drying and curing the resulting coating. The coating liquid for forming an antireflection layer may contain, for example, a curable compound, a fluorine-containing additive, hollow particles, a solvent, etc., and can be obtained, for example, by mixing these.

[0035] The curing mechanism of the curable compound contained in the coating liquid for forming an anti-reflection layer can be, for example, a heat-curable type or a photo-curable type. As the curable compound, for example, a compound having at least one of an acrylate group and a methacrylate group is used, and examples thereof include oligomers or prepolymers of acrylates or methacrylates of polyfunctional compounds such as silicone resins, polyester resins, polyether resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiolpolyene resins, and polyhydric alcohols. These compounds can be used alone or in combination of two or more.

[0036] The curable compound may also contain a reactive diluent having at least one of an acrylate group and a methacrylate group. Examples of the reactive diluent include those described in JP 2008-88309 A, including monofunctional acrylates, monofunctional methacrylates, polyfunctional acrylates, and polyfunctional methacrylates. From the viewpoint of achieving excellent hardness, trifunctional or higher acrylates and trifunctional or higher methacrylates are preferably used as the reactive diluent. Examples of the reactive diluent include butanediol glycerin ether diacrylate, acrylate of isocyanuric acid, and methacrylate of isocyanuric acid. These may be used alone or in combination of two or more. A curing agent may be used to cure the curable compound. Examples of the curing agent include known polymerization initiators (e.g., thermal polymerization initiators, photopolymerization initiators, etc.).

[0037] The fluorine-containing additive may be, for example, a fluorine-containing organic compound or a fluorine-containing inorganic compound. Examples of fluorine-containing organic compounds include fluorine-containing antifouling coating agents, fluorine-containing acrylic compounds, and fluorine-silicon-containing acrylic compounds. Commercially available fluorine-containing organic compounds can be used. Specific examples of commercially available products include "KY-1203" manufactured by Shin-Etsu Chemical Co., Ltd. and "Megafac" manufactured by DIC Corporation. The content of the fluorine-containing additive may be, for example, 0.05 parts by weight or more, 0.1 parts by weight or more, 0.15 parts by weight or more, 0.20 parts by weight or more, or 0.25 parts by weight or more, or 20 parts by weight or less, 15 parts by weight or less, 10 parts by weight or less, 5 parts by weight or less, or 3 parts by weight or less, relative to 100 parts by weight of the curable compound.

[0038] Examples of hollow particles that can be used include silica particles, acrylic particles, and acrylic-styrene copolymer particles. Commercially available hollow silica particles (e.g., trade names "Sururia 5320" and "Sururia 4320" manufactured by JGC Catalysts and Chemicals Industries, Ltd.) can be used. The weight-average particle diameter of the hollow particles can be, for example, 30 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, or 70 nm or more, or 150 nm or less, 140 nm or less, 130 nm or less, 120 nm or less, or 110 nm or less. The shape of the hollow particles is not particularly limited, but is preferably approximately spherical. Specifically, the aspect ratio of the hollow particles is preferably 1.5 or less.

[0039] The content of the hollow particles is, for example, 11 parts by weight or more, optionally 12 parts by weight or more, or even 15 parts by weight or more, relative to 100 parts by weight of the curable compound (resin component after curing). Within such a range, sufficient anti-reflection function can be obtained. Meanwhile, the content of the hollow particles is, for example, 40 parts by weight or less, optionally 30 parts by weight or less, or even 24 parts by weight or less, relative to 100 parts by weight of the curable compound (resin component after curing). In one embodiment, the haze can be adjusted by adjusting the content of the hollow particles in the anti-reflection layer and the type and content of the filler contained in the anti-glare layer.

[0040] Any appropriate solvent can be used as the solvent. Examples of the solvent include alcohols such as methanol, ethanol, isopropyl alcohol, butanol, TBA (tertiary butyl alcohol), and 2-methoxyethanol; ketones such as acetone, methyl ethyl ketone, MIBK (methyl isobutyl ketone), and cyclopentanone; esters such as methyl acetate, ethyl acetate, butyl acetate, and PMA (propylene glycol monomethyl ether acetate); ethers such as diisopropyl ether and propylene glycol monomethyl ether; glycols such as ethylene glycol and propylene glycol; cellosolves such as ethyl cellosolve and butyl cellosolve; aliphatic hydrocarbons such as hexane, heptane, and octane; and aromatic hydrocarbons such as benzene, toluene, and xylene. These solvents may be used alone or in combination. The solvent content may be, for example, such that the weight of the solids relative to the total weight of the anti-reflection layer-forming coating liquid is, for example, 0.1 wt % or more, 0.3 wt % or more, 0.5 wt % or more, 1.0 wt % or more, or 1.5 wt % or more, or 20 wt % or less, 15 wt % or less, 10 wt % or less, 5 wt % or less, or 3 wt % or less.

[0041] The coating solution for forming the antireflection layer can be applied by known coating methods such as fountain coating, die coating, spin coating, spray coating, gravure coating, roll coating, and bar coating. The drying temperature of the coating film is, for example, 30°C to 200°C, and the drying time is, for example, 30 to 90 seconds. The coating film can be cured by, for example, heating or light irradiation (typically, ultraviolet irradiation). A high-pressure mercury lamp, for example, is used as a light source for light irradiation. The dose of ultraviolet irradiation is 50 mJ / cm as the cumulative exposure dose at an ultraviolet wavelength of 365 nm. 2 ~500mJ / cm 2 It is preferable that:

[0042] The thickness of the antireflection layer is preferably 0.1 μm to 2 μm, and more preferably 0.1 μm to 1 μm.

[0043] The thickness of the surface treatment layer is, for example, 1 μm to 20 μm, preferably 4 μm to 14 μm, and more preferably 6 μm to 10 μm.

[0044] [Phase contrast layer] The retardation layer may have an in-plane retardation. In one embodiment, the retardation layer may function as a λ / 4 plate. Specifically, the in-plane retardation Re(550) of the retardation film is, for example, 100 nm to 190 nm, preferably 110 nm to 180 nm, more preferably 120 nm to 170 nm, even more preferably 130 nm to 160 nm, and particularly preferably 135 nm to 155 nm. The configuration of the retardation layer is not particularly limited, and may be, for example, a resin film or a layer of liquid crystal compound alignment (liquid crystal alignment layer). Here, the term "alignment layer" refers to a layer in which the liquid crystal compound is aligned in a predetermined direction within the layer and the alignment state is fixed. The term "alignment layer" encompasses a concept including an alignment layer obtained by curing a liquid crystal monomer. [Example]

[0045] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The thickness, reflectance, haze, and transmittance are values ​​measured by the following measurement methods. Unless otherwise specified, "parts" and "%" in the examples and comparative examples are by weight. 1. Thickness Thicknesses of 10 μm or less were measured using a scanning electron microscope (manufactured by JEOL Ltd., product name "JSM-7100F"), and thicknesses of more than 10 μm were measured using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C"). 2. Hayes Measurements were made using a haze meter (product name "HN-150" manufactured by Murakami Color Science Laboratory Co., Ltd.) in accordance with JIS 7136. To measure the reflectance of the surface-treated layer side of the laminated film, the laminated film was attached to a black acrylic plate with an adhesive to prepare a measurement sample. 3.Reflectance Measurements were made using an ultraviolet-visible-infrared spectrophotometer (Hitachi High-Tech Science Corporation, product name "U-4100"). To measure the reflectance of the surface treatment layer side of the laminated film, the laminated film was attached to a black acrylic plate with adhesive to prepare a measurement sample. Measurements were made at wavelengths of 380 nm to 780 nm. 4.Transmittance Measurement was performed using an ultraviolet-visible spectrophotometer ("V7100" manufactured by JASCO Corporation). The transmittance is a Y value measured using a 2-degree visual field (C light source) according to JIS Z8701 and corrected for visibility.

[0046] [Example 1] (Fabrication of polarizer) A long roll of a 30 μm-thick polyvinyl alcohol (PVA) resin film (manufactured by Kuraray, product name "PE3000") was uniaxially stretched in the longitudinal direction by 5.9 times using a roll stretching machine while simultaneously undergoing swelling, dyeing, crosslinking, and washing treatments in this order, and finally drying treatment, to produce a 12 μm-thick polarizer. The swelling treatment involved stretching the film 2.2 times while treating it in pure water at 20°C. Next, the dyeing treatment involved stretching the film 1.4 times while treating it in a 30°C aqueous solution containing iodine and potassium iodide at a weight ratio of 1:7, with the iodine concentration adjusted so that the resulting polarizer's single transmittance was the desired value. Next, the crosslinking treatment involved a two-stage crosslinking treatment. In the first stage, the film was stretched 1.2 times while treating it in a 40°C aqueous solution containing boric acid and potassium iodide. The boric acid content of the aqueous solution used in the first stage was 5.0 wt % and the potassium iodide content was 3.0 wt %. In the second stage, the film was stretched 1.6 times while treating it in a 65°C aqueous solution containing boric acid and potassium iodide. The boric acid content of the aqueous solution used in the second stage was 4.3 wt % and the potassium iodide content was 5.0 wt %. Next, the film was washed with an aqueous potassium iodide solution at 20° C. The potassium iodide content of the aqueous solution used for the washing treatment was 2.6% by weight. Finally, the film was dried at 70° C. for 5 minutes to obtain a polarizer.

[0047] (Preparation of laminated film) A surface treatment layer was formed on a 25 μm-thick TAC film by the procedure described below to obtain a laminated film (haze: 2.5%, reflectance: 1.5%).

[0048] (Formation of surface treatment layer) 1. Formation of anti-glare layer (anti-glare hard coat layer) A mixture of 80 parts by weight of an ultraviolet-curable urethane acrylate resin (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., product name "UV1700B", solid content 100%) and 20 parts by weight of a multifunctional acrylate containing pentaerythritol triacrylate as the main component (manufactured by Osaka Organic Chemical Industry Ltd., product name "Viscoat #300", solid content 100%) was prepared. For 100 parts by weight of the resin solids of the mixture, 2 parts by weight of cross-linked polymethyl methacrylate particles (manufactured by Sekisui Chemical Co., Ltd., trade name "Techpolymer", weight average particle size: 5 μm, refractive index: 1.51), 0.4 parts by weight of synthetic smectite (manufactured by Co-op Chemical Co., Ltd., trade name "Lucentite SAN"), which is an organoclay (thixotropy-imparting agent), 3 parts by weight of photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907"), and 0.05 parts by weight of leveling agent (manufactured by DIC Corporation, trade name "PC4100", solids content 10%) were mixed. Here, the organoclay was diluted with toluene to a solids content of 6%. The resulting mixture was diluted with a toluene / cyclopentanone (CPN) mixed solvent (weight ratio 80 / 20) so that the solid content concentration was 40% by weight, to prepare a material (coating liquid) for forming an antiglare layer.

[0049] The obtained antiglare layer-forming material (coating liquid) was applied onto a TAC film (thickness: 25 μm, Fujifilm Corporation, product name "TJ25UL") using a wire bar. The coating film was then dried by heating at 95°C for 1 minute, and then irradiated with a high-pressure mercury lamp at an integrated light intensity of 300 mJ / cm. 2 The coating film was irradiated with ultraviolet light so that an antiglare layer having a thickness of 6.5 μm was formed.

[0050] 2. Formation of anti-reflection layer A mixture of 100 parts by weight of a multifunctional acrylate (Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #300", solids content 100 wt%) based on pentaerythritol triacrylate, 100 parts by weight of hollow nanosilica particles (JGC Catalysts and Chemicals Industries, Ltd., trade name "Surulia 5320", solids content 20 wt%, weight average particle diameter 75 nm), 12 parts by weight of a fluorine-containing additive (Shin-Etsu Chemical Co., Ltd., trade name "KY-1203", solids content 20 wt%), and 3 parts by weight of a photopolymerization initiator (BASF, trade name "OMNIRAD 907", solids content 100 wt%) was added to the mixture. A 60:25:15 mixed solvent of TBA, MIBK, and PMA was added to the mixture to a total solids content of 4 wt%, and the mixture was stirred to prepare a coating solution for forming an anti-reflection layer.

[0051] The obtained coating liquid for forming an antireflection layer was applied onto the antiglare layer using a wire bar. The applied coating liquid was heated at 80°C for 1 minute and dried to form a coating film. The obtained coating film was irradiated with an integrated light dose of 300 mJ / cm from a high-pressure mercury lamp. 2 The coating was cured by irradiating it with ultraviolet light of 1000 kJ / cm2 to form an anti-reflection layer having a thickness of 0.1 μm. In this way, a surface treatment layer was formed.

[0052] (Preparation of polarizing plate) A laminated film was attached to one side of the obtained polarizer via an ultraviolet-curable adhesive so that the TAC film faced the polarizer. A 25 μm thick TAC film was attached to the other side of the polarizer via a UV-curable adhesive to obtain a laminate (transmittance: 46.0%). A retardation film (polycarbonate resin film, thickness: 50 μm, Re(550): 147 nm, Teijin Limited, product name "Pure Ace RM") was then attached via a 12 μm thick acrylic adhesive layer, followed by forming a 15 μm thick acrylic adhesive layer to obtain a polarizing plate.

[0053] [Example 2] A polarizing plate was obtained in the same manner as in Example 1, except that the iodine concentration during dyeing in the production of the polarizer was changed and the surface treatment layer was formed according to the following procedure.

[0054] (Formation of surface treatment layer) 1. Formation of anti-glare layer (anti-glare hard coat layer) To 100 parts by weight of ultraviolet-curable urethane acrylate resin (DIC Corporation, "UNIDIC 17-806"), 6.5 parts by weight of silicon oxide particles (Fuji Silysia Chemical Ltd., "Sylohorbic 702"), 6.5 parts by weight of silicon oxide particles (Fuji Silysia Chemical Ltd., "Sylohorbic 100"), and 2.5 parts by weight of synthetic smectite (manufactured by Co-op Chemical Co., Ltd., trade name "Lucentite SAN"), which is an organoclay (thickener), were added, and further 5 parts by weight of photopolymerization initiator (BASF, "OMNIRAD184") and 0.5 parts by weight of leveling agent (DIC Corporation, "Megafac F-556") were added and mixed. The resulting mixture was diluted with toluene so that the solid content concentration was 30% by weight, to prepare a material (coating liquid) for forming an antiglare layer.

[0055] The obtained antiglare layer-forming material (coating liquid) was applied onto a TAC film (thickness 25 μm, Fujifilm Corporation, product name "TJ25UL") using a wire bar. The coating film was then dried by heating at 110°C for 1 minute, and then irradiated with a high-pressure mercury lamp at an integrated light intensity of 300 mJ / cm. 2 The coating film was irradiated with ultraviolet light so that an antiglare layer having a thickness of 8.0 μm was formed.

[0056] 2. Formation of anti-reflection layer A mixture of 100 parts by weight of a multifunctional acrylate (Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #300", solids content 100 wt%) based on pentaerythritol triacrylate, 180 parts by weight of hollow nanosilica particles (JGC Catalysts and Chemicals Industries Co., Ltd., trade name "Surulia 5320", solids content 20 wt%, weight average particle diameter 75 nm), 12 parts by weight of a fluorine-containing additive (Shin-Etsu Chemical Co., Ltd., trade name "KY-1203", solids content 20 wt%), and 3 parts by weight of a photopolymerization initiator (BASF, trade name "OMNIRAD 907", solids content 100 wt%) was added to the mixture as a solvent. A 60:25:15 mixed solvent of TBA, MIBK, and PMA was added to the mixture to a total solids content of 4 wt%, and the mixture was stirred to prepare a coating solution for forming an anti-reflection layer.

[0057] The obtained coating liquid for forming an antireflection layer was applied onto the antiglare layer using a wire bar. The applied coating liquid was heated at 80°C for 1 minute and dried to form a coating film. The obtained coating film was irradiated with an integrated light dose of 300 mJ / cm from a high-pressure mercury lamp. 2 The coating was cured by irradiating it with ultraviolet light of 1000 kJ / cm2 to form an anti-reflection layer having a thickness of 0.1 μm. In this way, a surface treatment layer was formed.

[0058] [Comparative Example 1] A polarizing plate was obtained in the same manner as in Example 1, except that the iodine concentration during dyeing in the production of the polarizer was changed and the surface treatment layer was formed according to the following procedure.

[0059] (Formation of surface treatment layer) 100 parts by weight of an ultraviolet-curable acrylate resin (manufactured by DIC Corporation, trade name "Luxidia 17-806", solid content 80%), 3 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907"), and 0.01 parts by weight of a leveling agent (manufactured by DIC Corporation, trade name "PC4100", solid content 10%) were mixed. The resulting mixture was diluted with a PGM (propylene glycol monomethyl ether) / cyclopentanone mixed solvent (weight ratio 63 / 37) so that the solid content concentration was 36%, to prepare a coating liquid for forming a hard coat layer.

[0060] The obtained hard coat layer-forming coating solution was applied onto a TAC film (thickness 25 μm, Fujifilm Corporation, product name "TJ25UL") using a wire bar. The coating film was then dried by heating at 95°C for 1 minute, and then irradiated with a high-pressure mercury lamp at an integrated light intensity of 300 mJ / cm. 2 The coating film was irradiated with ultraviolet light so that a 6.5 μm thick antiglare hard coat layer (surface treatment layer) was formed.

[0061] Comparative Example 2 A polarizing plate was obtained in the same manner as in Comparative Example 1, except that the iodine concentration during dyeing in the production of the polarizer was changed.

[0062] Comparative Example 3 A polarizing plate was obtained in the same manner as in Example 1, except that the iodine concentration during dyeing in the production of the polarizer was changed and the surface treatment layer was formed according to the following procedure.

[0063] (Formation of surface treatment layer) A mixture of 100 parts by weight of a multifunctional acrylate (Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #300", solids content 100 wt%) based on pentaerythritol triacrylate, 100 parts by weight of hollow nanosilica particles (JGC Catalysts and Chemicals Industries Co., Ltd., trade name "Sururia 5320", solids content 20 wt%, weight average particle diameter 75 nm), 12 parts by weight of a fluorine-containing additive (Shin-Etsu Chemical Co., Ltd., trade name "KY-1203", solids content 20 wt%), and 3 parts by weight of a photopolymerization initiator (BASF, trade name "OMNIRAD 907", solids content 100 wt%) was added to the mixture. A 60:25:15 mixed solvent of TBA, MIBK, and PMA was added to the mixture to a total solids content of 4 wt%, and the mixture was stirred to prepare a coating solution for forming an anti-reflection layer.

[0064] The obtained coating solution for forming an antireflection layer was applied to a TAC film (thickness: 25 μm, Fujifilm Corporation, product name "TJ25UL") using a wire bar. The applied coating solution was heated at 80°C for 1 minute and dried to form a coating film. The obtained coating film was irradiated with a high-pressure mercury lamp with an integrated light intensity of 300 mJ / cm. 2 The coating was subjected to a curing treatment by irradiating it with ultraviolet light of 1000 kJ / cm2, thereby forming an anti-reflection layer (surface treatment layer) having a thickness of 0.1 μm.

[0065] Comparative Example 4 A polarizing plate was obtained in the same manner as in Example 1, except that the iodine concentration during dyeing was changed in the production of the polarizer.

[0066] Comparative Example 5 A polarizing plate was obtained in the same manner as in Example 1, except that the iodine concentration during dyeing in the production of the polarizer was changed and the surface treatment layer was formed according to the following procedure.

[0067] (Formation of surface treatment layer) 1. Formation of anti-glare layer (anti-glare hard coat layer) To 100 parts by weight of ultraviolet-curable urethane acrylate resin (DIC Corporation, "UNIDIC 17-806"), 7 parts by weight of silicon oxide particles (Fuji Silysia Chemical Ltd., "Sylohorbic 702"), 6.5 parts by weight of silicon oxide particles (Fuji Silysia Chemical Ltd., "Sylohorbic 100"), 5 parts by weight of photopolymerization initiator (BASF, "OMNIRAD184"), and 0.5 parts by weight of leveling agent (DIC Corporation, "Megafac F-556") were added and mixed. The resulting mixture was diluted with toluene so that the solid content concentration was 30% by weight, to prepare a material (coating liquid) for forming an antiglare layer.

[0068] The obtained antiglare layer-forming material (coating liquid) was applied onto a TAC film (thickness 25 μm, Fujifilm Corporation, product name "TJ25UL") using a wire bar. The coating film was then dried by heating at 110°C for 1 minute, and then irradiated with a high-pressure mercury lamp at an integrated light intensity of 300 mJ / cm. 2The coating film was irradiated with ultraviolet light so that an antiglare layer having a thickness of 5.0 μm was formed.

[0069] 2. Formation of anti-reflection layer A mixture of 100 parts by weight of a multifunctional acrylate (Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #300", solids content 100 wt%) based on pentaerythritol triacrylate, 60 parts by weight of hollow nanosilica particles (JGC Catalysts and Chemicals Industries Co., Ltd., trade name "Sururia 5320", solids content 20 wt%, weight average particle diameter 75 nm), 12 parts by weight of a fluorine-containing additive (Shin-Etsu Chemical Co., Ltd., trade name "KY-1203", solids content 20 wt%), and 3 parts by weight of a photopolymerization initiator (BASF, trade name "OMNIRAD 907", solids content 100 wt%) was added to the mixture. A 60:25:15 mixed solvent of TBA, MIBK, and PMA was added to the mixture to a total solids content of 4 wt%, and the mixture was stirred to prepare a coating solution for forming an anti-reflection layer.

[0070] The obtained coating liquid for forming an antireflection layer was applied onto the antiglare layer using a wire bar. The applied coating liquid was heated at 80°C for 1 minute and dried to form a coating film. The obtained coating film was irradiated with an integrated light dose of 300 mJ / cm from a high-pressure mercury lamp. 2 The coating was cured by irradiating it with ultraviolet light of 1000 kJ / cm2 to form an anti-reflection layer having a thickness of 0.1 μm. In this way, a surface treatment layer was formed.

[0071] Comparative Example 6 A polarizing plate was obtained in the same manner as in Example 1, except that the iodine concentration during dyeing in the production of the polarizer was changed and the surface treatment layer was formed according to the following procedure.

[0072] (Formation of surface treatment layer) A mixture of 100 parts by weight of a multifunctional acrylate (Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #300", solids content 100 wt%) based on pentaerythritol triacrylate, 70 parts by weight of hollow nanosilica particles (JGC Catalysts and Chemicals Industries, Ltd., trade name "Sururia 5320", solids content 20 wt%, weight average particle diameter 75 nm), 12 parts by weight of a fluorine-containing additive (Shin-Etsu Chemical Co., Ltd., trade name "KY-1203", solids content 20 wt%), and 3 parts by weight of a photopolymerization initiator (BASF, trade name "OMNIRAD 907", solids content 100 wt%) was added to the mixture. A 60:25:15 mixed solvent of TBA, MIBK, and PMA was added to the mixture to a total solids content of 4 wt%, and the mixture was stirred to prepare a coating solution for forming an anti-reflection layer.

[0073] The obtained coating solution for forming an antireflection layer was applied to a TAC film (thickness: 25 μm, Fujifilm Corporation, product name "TJ25UL") using a wire bar. The applied coating solution was heated at 80°C for 1 minute and dried to form a coating film. The obtained coating film was irradiated with a high-pressure mercury lamp with an integrated light intensity of 300 mJ / cm. 2 The coating was subjected to a curing treatment by irradiating it with ultraviolet light of 1000 kJ / cm2, thereby forming an anti-reflection layer (surface treatment layer) having a thickness of 0.1 μm.

[0074] The following evaluations were carried out for the Examples and Comparative Examples. The evaluation results are summarized in Table 1. <Evaluation> 1. Moire The obtained polarizing plate was visually observed from the surface treatment layer side under a fluorescent light environment to check for the occurrence of moire (rainbow patterns). 2. White blur The obtained polarizing plate was visually observed from the surface treatment layer side in a bright room environment to check the occurrence of white blur due to diffuse reflection of light. 3. Reflections The obtained polarizing plate was visually observed from the surface treatment layer side under a fluorescent light environment to check the occurrence of reflections. 4. Screen burn-in After removing the front glass plate and polarizing plate from a Samsung Galaxy A41 equipped with an organic EL panel, the obtained polarizing plate was attached to the surface of the organic EL panel to obtain a test screen. As shown in Figure 3, a predetermined character was displayed in black at the top left corner of the obtained test screen, and the point in the center was used as the measurement point. The luminance of the measurement point was measured using the "SR-UL1R" manufactured by Topcon. 2 The display of the test screen was adjusted so that it was luminous (equivalent to outdoor luminance). After lighting for 30 hours in this state, the luminance at the measurement points was measured and the luminance decrease rate was calculated. After lighting, the entire screen was displayed in white and the test screen was visually observed.

[0075] [Table 1]

[0076] The embodiment is excellent in all aspects of moire, white blur, reflection and screen burn-in, and can be suitably used in, for example, laptop-type personal computers. In Comparative Examples 1 and 3-6, where the brightness reduction rate exceeded 1%, the brightness of the area other than the part of the characters displayed at the upper left corner decreased, and the displayed characters appeared to stand out in white. [Industrial Applicability]

[0077] The polarizing plate obtained by the embodiment of the present invention can be suitably used as a polarizing plate for image display devices, representative examples of which include organic EL display devices, inorganic EL display devices, and liquid crystal display devices. [Explanation of symbols]

[0078] 10 Polarizer 20 Laminated Film 21 Base material (protective layer) 22 Surface treatment layer 30 protective layer 40 Retardation layer 50 adhesive layer 70 Image display (organic EL) panel body 100 Polarizer 200 Image display (organic EL) panel

Claims

[Claim 1] a laminated film having a substrate and a surface treatment layer; a polarizer disposed on the substrate side of the laminated film, the reflectance of the surface treatment layer side is 2% or less, and the haze of the surface treatment layer side is 1% or more and 13% or less; The transmittance is 45.5% or more, Used in organic EL panels, Polarizing plate.

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