Anti-glare film and image display device using the same

Abstract

To provide an anti-glare film capable of achieving both anti-glare properties and glaring-resistant properties even when used in a high-definition image display device and the image display device using the same.SOLUTION: There is provided an anti-glare film which comprises at least one anti-glare layer laminated on a transparent substrate and has an uneven shape on its outermost surface. The anti-glare film is characterized in that the number of protrusions having an arithmetic mean height Sa or more present on the outermost surface measured by an optical interference method is 600 or more per measurement area.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an antiglare film that reduces reflection of external light and an image display device using the same. [Background technology]

[0002] Anti-glare films (also called anti-glare (AG) films) have an anti-glare layer in which inorganic materials or fillers are dispersed in a resin layer on a transparent substrate. Anti-glare films improve visibility by scattering surface-reflected light using the uneven surface of the top surface and blurring the image of reflected external light. Compared to anti-reflection films, which have no uneven surface and prevent reflections by using light interference, anti-glare films reduce the reflection of images such as people and backgrounds, making it possible to clearly view displayed images when used in image display devices.

[0003] In recent years, with the trend toward higher resolution image display devices, there has been a demand for improved anti-glare properties of anti-glare films. For example, Patent Document 1 describes an anti-glare film in which the three-dimensional arithmetic mean roughness of the anti-glare layer surface satisfies predetermined conditions, thereby suppressing glare and preventing a decrease in contrast even when used in a high-resolution image display device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7192777 Summary of the Invention [Problem to be solved by the invention]

[0005] The anti-glare properties of an anti-glare film can be improved by increasing the number of irregularities on the outermost surface or by increasing the size of the irregularities, but the increased lens effect caused by the irregular shape of the outermost surface deteriorates the anti-glare properties. In other words, in an anti-glare film, there is a trade-off between the anti-glare properties obtained by the irregular shape of the outermost surface and the anti-glare properties.

[0006] Therefore, an object of the present invention is to provide an anti-glare film that can achieve both anti-glare properties and anti-glare properties even when used in a high-definition image display device, and an image display device using the same. [Means for solving the problem]

[0007] An antiglare film according to one embodiment of the present invention comprises at least one antiglare layer laminated on a transparent substrate, an outermost surface having an uneven shape, and a number of convex portions having an arithmetic mean height Sa or more present on the outermost surface as measured by an optical interference method, 701.826×936.116μm 2 It is characterized by having 600 or more per unit area. Here, the number of convex portions is a value calculated by measuring three-dimensional data of the uneven shape of the outermost surface of the antiglare film using an optical interference method, filtering, surface correction, and interpolation processing of the three-dimensional height data obtained by the measurement, then performing a Fourier transform, extracting short-wavelength components from the obtained spectral data using a 0.8 to 50 μm bandpass filter, then performing an inverse Fourier transform on the extracted spectral data to obtain an analysis image, and analyzing the analysis image.

[0008] An antiglare film according to another embodiment of the present invention comprises at least one antiglare layer laminated on a transparent substrate, an outermost surface having an uneven shape, and a plane parallel to the average plane of the uneven shape and having a height equal to the arithmetic mean height Sa from the average plane. , forming a concave-convex shape When the convex part is cut, the cross-sectional area is 150 μm 2 The number of convex portions that is less than 701.826×936.116μm 2 It is characterized by having 480 or more per unit area. Here, the number of convex portions is a value calculated by measuring three-dimensional data of the uneven shape of the outermost surface of the antiglare film using an optical interference method, filtering, surface correction, and interpolation processing of the three-dimensional height data obtained by the measurement, then performing a Fourier transform, extracting short-wavelength components from the obtained spectral data using a 0.8 to 50 μm bandpass filter, then performing an inverse Fourier transform on the extracted spectral data to obtain an analysis image, and analyzing the analysis image.

[0009] A display device according to the present invention includes any one of the antiglare films described above. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an anti-glare film that can achieve both anti-glare properties and anti-glare properties even when used in a high-definition image display device, and an image display device using the same. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view schematically illustrating an example of an antiglare film according to an embodiment. [Figure 2]FIG. 1 is a cross-sectional view schematically showing another example of an antiglare film according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] FIG. 1 is a cross-sectional view schematically illustrating an example of an antiglare film according to an embodiment.

[0013] The antiglare film 11 includes a transparent substrate 2 and an antiglare layer 3 laminated on one surface of the transparent substrate 2. The antiglare film 11 is an optical film (also called an "AG film") that scatters incident light using the fine unevenness on the surface of the antiglare layer 3 to suppress reflections of external light.

[0014] The transparent substrate 2 is a film that serves as the base of the antiglare film 11 and is made of a material that is highly transparent to visible light. Materials that can be used to form the transparent substrate 2 include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyacrylates such as polymethyl methacrylate, polyamides such as nylon 6 and nylon 66, polyimides, polyarylates, polycarbonates, triacetyl cellulose, polyacrylates, polyvinyl alcohol, polyvinyl chloride, cycloolefin copolymers, norbornene-containing resins, polyethersulfones, and transparent resins such as polysulfones, and inorganic glass. The thickness of the transparent substrate 2 is not particularly limited, but is preferably 10 to 200 μm.

[0015] The surface of the transparent substrate 2 may be subjected to a surface modification treatment to improve adhesion with other layers to be laminated thereon. Examples of surface modification treatments include alkali treatment, corona treatment, plasma treatment, sputtering treatment, application of a surfactant or a silane coupling agent, and Si vapor deposition.

[0016] The antiglare layer 3 is a functional layer that forms a fine uneven shape on the outermost surface of the antiglare film 11, and contains fine particles (shown as circles in the drawings.) The thickness of the antiglare layer 3 is not particularly limited, but is preferably 1.3 to 5.0 μm.

[0017] The antiglare layer 3 is formed by applying a coating liquid containing an active energy ray-curable compound and fine particles (organic filler) to the transparent substrate 2 and curing the coating film.

[0018] As the active energy ray-curable compound, for example, a monofunctional, bifunctional, trifunctional or higher functional (meth)acrylate monomer can be used. In this specification, "(meth)acrylate" is a general term for both acrylate and methacrylate, and "(meth)acryloyl" is a general term for both acryloyl and methacryloyl. The (meth)acrylate monomer may contain fluorine.

[0019] Examples of monofunctional (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, glycidyl (meth)acrylate, acryloylmorpholine, N-vinylpyrrolidone, tetrahydrofurfuryl acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and isobornyl (meth)acrylate. , isodecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, benzyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethyl carbitol (meth)acrylate, phosphate (meth)acrylate, ethylene oxide-modified phosphate (meth)acrylate, phenoxy (meth)acrylate, ethylene oxide-modified phenoxy (meth)acrylate, propylene oxide Oxide-modified phenoxy (meth)acrylate, nonylphenol (meth)acrylate, ethylene oxide-modified nonylphenol (meth)acrylate, propylene oxide-modified nonylphenol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypropylene glycol (meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, ) acryloyloxyethyl hydrogen phthalate, 2-(meth)acryloyloxypropyl hydrogen phthalate, 2-(meth)acryloyloxypropyl hexahydrohydrogen phthalate, 2-(meth)acryloyloxypropyl tetrahydrohydrogen phthalate, dimethylaminoethyl (meth)acrylate, trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropropyl (meth)acrylate, 2-adamantane,Examples include adamantane derivative mono(meth)acrylates such as adamantyl acrylate having a monovalent mono(meth)acrylate derived from adamantanediol.

[0020] Examples of bifunctional (meth)acrylates include di(meth)acrylates such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, nonanediol di(meth)acrylate, ethoxylated hexanediol di(meth)acrylate, propoxylated hexanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethoxylated neopentyl glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and hydroxypivalic acid neopentyl glycol di(meth)acrylate.

[0021] Examples of tri- or higher functional (meth)acrylates include tri(meth)acrylates such as trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, and glycerin tri(meth)acrylate; trifunctional (meth)acrylate compounds such as pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, and ditrimethylolpropane tri(meth)acrylate; Examples of the polyfunctional (meth)acrylate compound include tri- or higher functional polyfunctional (meth)acrylate compounds such as pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, ditrimethylolpropane penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and ditrimethylolpropane hexa(meth)acrylate, as well as polyfunctional (meth)acrylate compounds in which a portion of these (meth)acrylates is substituted with an alkyl group or ε-caprolactone.

[0022] Urethane (meth)acrylates can also be used as polyfunctional monomers. Examples of urethane (meth)acrylates include those obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer, and then reacting the resulting product with a (meth)acrylate monomer having a hydroxyl group.

[0023] Examples of urethane (meth)acrylates include pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, dipentaerythritol pentaacrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate toluene diisocyanate urethane prepolymer, dipentaerythritol pentaacrylate toluene diisocyanate urethane prepolymer, pentaerythritol triacrylate isophorone diisocyanate urethane prepolymer, and dipentaerythritol pentaacrylate isophorone diisocyanate urethane prepolymer.

[0024] The polyfunctional monomers may be used alone or in combination of two or more thereof. In addition, the polyfunctional monomers may be in the form of a monomer in the coating liquid, or may be in the form of a partially polymerized oligomer.

[0025] The fine particles (organic filler) are a material that primarily forms minute irregularities on the surface of the anti-glare layer 3, imparting the function of diffusing external light. Examples of organic fillers that can be used include resin particles made of translucent resin materials such as acrylic resin, polystyrene resin, styrene-(meth)acrylic acid ester copolymer, polyethylene resin, epoxy resin, silicone resin, polyvinylidene fluoride, and polyethylene fluoride resin. To adjust the refractive index and dispersion of the resin particles, two or more types of resin particles with different materials (refractive indexes) may be mixed. The average particle size of the organic filler is preferably 0.5 to 5.5 μm. When the average particle size of the organic filler exceeds 5.5 μm, the number of particles is smaller than when the average particle size of the organic filler is 5.5 μm or less for a given mass of organic filler. This reduces the number of convex portions formed, and tends to result in reduced anti-glare properties. The refractive index of the organic filler, although depending on the refractive index of the binder resin (active energy ray-curable resin), is preferably 1.495 to 1.595. The amount of the organic filler to be added varies depending on the particle size, but is preferably 2 to 20% by mass of the total solid content of the composition for forming an antiglare layer.

[0026] The composition for forming an antiglare layer may further contain inorganic fine particles. The inorganic fine particles added to the composition particles for forming an antiglare layer are preferably nanoparticles having an average particle size of 10 to 200 nm.

[0027] The inorganic fine particles are primarily materials for adjusting the sedimentation and aggregation of the fine particles (organic filler) in the antiglare layer 3. Examples of inorganic fine particles that can be used include silica fine particles, metal oxide fine particles, and various mineral fine particles. Examples of silica fine particles that can be used include colloidal silica and silica fine particles surface-modified with reactive functional groups such as (meth)acryloyl groups. Examples of metal oxide fine particles that can be used include alumina, zinc oxide, tin oxide, antimony oxide, indium oxide, titania, and zirconia. Examples of mineral fine particles that can be used include mica, synthetic mica, vermiculite, montmorillonite, iron-montmorillonite, bentonite, beidellite, saponite, hectorite, stevensite, nontronite, magadiite, ilealite, kanemite, layered titanic acid, smectite, and synthetic smectite. The mineral fine particles may be natural or synthetic (including substituted or derivative) materials, or a mixture of both. Among mineral fine particles, layered organic clay is more preferred. Layered organic clay refers to a swelling clay in which organic onium ions are introduced between the layers. The organic onium ions are not limited as long as they can be organized by utilizing the cation exchange properties of the swelling clay. When a layered organic clay mineral is used as the mineral fine particles, the above-mentioned synthetic smectite can be preferably used. Synthetic smectite has the function of increasing the viscosity of the composition for forming an antiglare layer, suppressing the sedimentation of resin particles and inorganic fine particles, and adjusting the uneven shape of the surface of the optical functional layer.

[0028] A polymerization initiator may be added to cure the antiglare layer-forming composition by ultraviolet irradiation. Polymerization initiators that generate radicals upon ultraviolet irradiation can be used. Radical polymerization initiators such as acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether, and acylphosphine oxides can be used as the polymerization initiator. Examples of polymerization initiators that can be used include diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-phenylacetophenone, dibenzoyl, benzoin, benzoin methyl ether, benzoin ethyl ether, p-chlorobenzophenone, p-methoxybenzophenone, Michler's ketone, acetophenone, and 2-chlorothioxanthone. One of these initiators may be used alone, or two or more may be used in combination.

[0029] Furthermore, it is preferable to add an antifouling agent, leveling agent, oil repellent, water repellent, or fingerprint inhibitor to the composition for forming the antiglare layer as a component for improving antifouling properties. Fluorine-containing compounds and silicone compounds can be suitably used as these additives. By adding an antifouling compound to the antiglare layer 3, which is the outermost layer, the ease of wiping off fingerprints can be further improved. Furthermore, various additives such as antistatic agents, antifoaming agents, antioxidants, ultraviolet absorbers, infrared absorbers, colorants, light stabilizers, polymerization inhibitors, and photosensitizers may be added as needed.

[0030] Furthermore, a solvent may be added to the antiglare layer-forming composition, if necessary. Examples of the solvent include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, butanol, isopropyl alcohol, and isobutanol; ketones such as acetone, methyl ethyl ketone, cyclohexanone, and methyl isobutyl ketone; ketone alcohols such as diacetone alcohol; aromatic hydrocarbons such as benzene, toluene, and xylene; glycols such as ethylene glycol, propylene glycol, and hexylene glycol; glycol ethers such as ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, diethyl cellosolve, diethyl carbitol, and propylene glycol monomethyl ether; esters such as methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, and amyl acetate; ethers such as dimethyl ether and diethyl ether; and N-methylpyrrolidone and dimethylformamide, which may be used alone or in combination.

[0031] FIG. 2 is a cross-sectional view schematically showing another example of the optical film according to the embodiment.

[0032] The antiglare film 12 includes a transparent substrate 2, an antiglare layer 3 laminated on one surface of the transparent substrate 2, and a low refractive index layer 4 laminated on the surface of the antiglare layer 3 and having a refractive index lower than that of the antiglare layer 3. The antiglare film 12 is an optical film (also called an "AGLR film") that suppresses glare and reflection of external light by utilizing scattering of incident light and optical interference caused by fine irregularities on the outermost surface.

[0033] A film made of the above-mentioned forming material can be used as the transparent substrate 2, and the antiglare layer 3 can be formed by applying the above-mentioned antiglare layer-forming composition to one surface of the transparent substrate 2, drying and curing it.

[0034] The low refractive index layer 4 is a functional layer that has a refractive index lower than that of the underlying antiglare layer 3 and suppresses reflection by optical interference. The thickness of the low refractive index layer 4 is not particularly limited, but is preferably 100 to 120 nm.

[0035] The low refractive index layer 4 can be formed by applying a composition containing an active energy ray-curable compound to the surface of the antiglare layer 3 and curing the coating. The low refractive index layer 4 may contain low refractive index fine particles to adjust the refractive index.

[0036] Examples of low refractive index particles include LiF, MgF2, NaF, and AlF 3、 Na3AlF 6、 Fine particles such as SiO2 can be used. As the silica particles, silica fine particles having voids therein can be suitably used. Silica fine particles having voids therein can have the refractive index of the voids (approximately 1) of air, which is advantageous for lowering the refractive index of the low refractive index layer 4. Specifically, porous silica particles and silica particles with a shell structure can be used. Note that low refractive index fine particles are not necessarily required, and if the refractive index of the active energy ray-curable compound after curing is lower than the refractive index of the antiglare layer 3, the low refractive index fine particles may be omitted.

[0037] As the active energy ray-curable compound, the polymerizable compound described in the antiglare layer can be used. In addition, the above-mentioned polymerization initiator and solvent may be appropriately added to the composition for forming the low refractive index layer.

[0038] Since the low refractive index layer 4 is a functional layer that serves as the outermost layer, it is preferable to add to the composition for forming the low refractive index layer components that improve antifouling properties, such as antifouling agents, leveling agents, oil repellents, water repellents, and fingerprint inhibitors. Fluorine-containing compounds and silicone compounds are suitable additives. Other additives, such as antistatic agents, antifoaming agents, antioxidants, ultraviolet absorbers, infrared absorbers, colorants, light stabilizers, polymerization inhibitors, and photosensitizers, may also be added as needed.

[0039] Between the transparent substrate 2 and the antiglare layer 3, one or more other functional layers such as a hard coat layer, a high refractive index layer, a medium refractive index layer, an antistatic layer, an electromagnetic wave blocking layer, an infrared absorbing layer, an ultraviolet absorbing layer, or a color correction layer may be laminated.

[0040] The method for applying the antiglare layer-forming composition and the low refractive index layer-forming composition is not particularly limited, and for example, they can be applied using a spin coater, a roll coater, a reverse roll coater, a gravure coater, a microgravure coater, a knife coater, a bar coater, a wire bar coater, a die coater, a dip coater, a spray coater, an applicator, or the like.

[0041] Here, the surface irregularities of the antiglare film according to this embodiment will be described in detail. The antiglare film according to this embodiment satisfies at least one of the following conditions (A) and (B).

[0042] Condition (A): The number of protrusions present on the outermost surface and having a height equal to or greater than the arithmetic mean height Sa is 600 or more per measurement area.

[0043] The number of convex portions having a height equal to or greater than the arithmetic mean height Sa can be obtained by measuring the outermost surface of the antiglare film using an optical interference method and analyzing the surface using the analysis software of the measuring device. When measured under the measurement conditions of the examples described later, the measured area is 701.826 × 936.116 μm 2 (≒ 0.657mm 2 The arithmetic mean height Sa is a value measured in accordance with ISO 25178-2 (2007) and 25178-3-2 (2010), and is defined as the average absolute value of the height of the convex portions from the average plane of all the irregularities present in the measurement area.

[0044] In this embodiment, the number of convex portions specified in the above condition (A) is expressed as the number of convex portions per measurement area set under the measurement conditions of the examples described below. However, if the number of convex portions having a height of Sa or more is expressed as the number per area different from the measurement area of ​​this embodiment, the number of convex portions converted into the number of measurement areas of this embodiment should be 600 or more.

[0045] When the number of convex portions defined by the above condition (A) is 600 or more per measurement area, glare can be reduced even when used in a high-resolution image display device with a resolution of 210 ppi or more, while ensuring high anti-glare properties. The number of convex portions present on the outermost surface and having a height equal to or greater than the arithmetic mean height Sa is a parameter that correlates with anti-glare properties, and the anti-glare properties improve as the number increases. There is no particular upper limit on the number of convex portions present on the outermost surface and having a height equal to or greater than the arithmetic mean height Sa, but it may be 2000 or less per measurement area, or it may be 1850 or less per measurement area.

[0046] Condition (B): When the convex portion is cut along a plane parallel to the average plane of the uneven shape of the outermost surface and having a height from the average plane equal to the arithmetic mean height Sa, the cross-sectional area is 150 μm 2 The number of convex portions that are less than 480 per measurement area.

[0047] The cross-sectional area when the convex portion is cut by a plane whose height from the average plane is equal to the arithmetic mean height Sa is 150 μm 2 The number of convex portions that is less than 1 / 2 is a value obtained by measuring the outermost surface of the antiglare film using an optical interference method and analyzing it using the analysis software of the measurement device. The measurement methods for the measured area and the arithmetic mean height Sa are the same as those described under condition (A).

[0048] In this embodiment, the number of convex portions specified in the above condition (B) is expressed as the number per measurement area set under the measurement conditions of the examples described later, provided that the cross-sectional area cut along a plane whose height from the average plane is equal to the arithmetic mean height Sa is 150 μm 2 If the number of convex portions that is less than the number per area is expressed as a number per area different from the measurement area of ​​this embodiment, the value converted from the number per different area to the number in the measurement area of ​​this embodiment should be 480 or more.

[0049] When the number of convex portions defined by the above condition (B) is 480 or more per measurement area, high antiglare properties can be ensured and glare can be reduced even when used in a high-resolution image display device with a resolution of 210 ppi or more. 2 The number of convex portions less than 150 μm is a parameter that correlates with anti-glare properties, and the more the number, the better the anti-glare properties. 2 There is no particular upper limit to the number of convex portions that is less than 2000 per measurement area, and it may be 2000 or less, or 1700 or less per measurement area.

[0050] The number of convex portions specified by the above conditions (A) and (B) can be controlled, for example, by adjusting the particle size and amount of the filler added to the antiglare layer 3, the amount of the additive, the film thickness of the antiglare layer 3, and the aggregation state of the filler during the film formation process.

[0051] The antiglare film according to this embodiment preferably has a transmitted image clarity of 92% or less. The transmitted image clarity is a value measured using a 0.5 mm-wide optical comb in accordance with JIS K 7374 (2007). If the transmitted image clarity of the antiglare film exceeds 92%, the light scattering effect at the outermost surface is weak, and the reflection of external light cannot be sufficiently reduced, which is undesirable.

[0052] Furthermore, it is preferable that the antiglare film according to this embodiment does not cause visible glare when a light source is observed while the film is placed on a black matrix with a resolution of 210 ppi or more. If glare is visible when a light source is observed while the film is placed on a black matrix with a resolution of less than 210 ppi, the film is not suitable for use as an antireflection film in recent high-resolution image display devices.

[0053] The antiglare film according to this embodiment can be used to construct an image display device by being attached to the outermost surface of an image display panel such as a liquid crystal panel or an organic EL panel. A touch panel may be provided between the antiglare film and the image display panel. The antiglare film according to this embodiment has excellent antiglare and anti-glare properties, and is therefore suitable as an optical film to be provided on the outermost surface of an image display device, particularly a high-resolution image display device with a resolution of 210 ppi or more. [Example]

[0054] Examples of specific implementations of the present invention will be described below.

[0055] (First layer forming composition) An antiglare layer (AG) or a clear hard coat layer (CHC) was formed as a first layer on a transparent substrate. The materials used in the composition for forming the first layer are shown below.

[0056] 1. Active energy ray curable resin Light Acrylate PE-3A (product name), Kyoeisha Chemical Co., Ltd., pentaerythritol triacrylate

[0057] 2. Photopolymerization initiator Omnirad® 184 (trade name), IGM Resins BV, 1-hydroxycyclohexyl-phenyl ketone

[0058] 3. Organic filler (fine particles) (1) Resin particle 1: diameter 1.5 μm, refractive index 1.495 (2) Resin particle 2: diameter 2.0 μm, refractive index 1.516 (3) Resin particle 3: diameter 3.4 μm, refractive index 1.564 (4) Resin particle 4: diameter 3.5 μm, refractive index 1.515 (5) Resin particle 5: diameter 3.5 μm, refractive index 1.590 (6) Resin particle 6: diameter 3.5 μm, refractive index 1.564 (7) Resin particle 7: diameter 5.3 μm, refractive index 1.544

[0059] 4. Thickener Sumecton SAN (product name), Kunimine Industries Co., Ltd., organic synthetic hectorite

[0060] 5.Leveling agent Megafac (registered trademark) F565 (product name), DIC Corporation

[0061] 6. Additives MEK-ST-40 (product name), Nissan Chemical Co., Ltd., organosilica sol

[0062] 7. Solvent toluene

[0063] (Composition for forming second layer) In Examples 3 and 4, a low refractive index layer (LR) having a thickness of 120 nm was formed as the second layer on the antiglare layer. The materials used in the composition for forming the second layer are shown below.

[0064] 1. Active energy ray curable resin (1) Light Acrylate PE-3A (product name), Kyoeisha Chemical Co., Ltd., pentaerythritol triacrylate (referred to as "PE-3A" in the table) (2) Fluorine-containing acrylate, Kyoeisha Chemical Co., Ltd.

[0065] 2. Photopolymerization initiator Omnirad® 184 (trade name), IGM Resins BV, 1-hydroxycyclohexyl-phenyl ketone

[0066] 3. Hollow silica particles Porous silica particles (diameter 75 nm), JGC Catalysts and Chemicals Co., Ltd.

[0067] 4.Leveling agent Megafac RS-75 (product name), DIC Corporation

[0068] 5. Solvent Meso-isobutyl ketone

[0069] (Examples 1, 2, 4 to 6 and Comparative Examples 1 to 6) Compositions for forming a first layer were prepared with the compositions shown in Tables 1 and 2. The compositions for forming a first layer were diluted with a solvent to a concentration suitable for coating. The compositions for forming a first layer were applied to one side of a 40 μm-thick triacetyl cellulose (TAC) film, dried, and then the coating was polymerized and cured by ultraviolet irradiation to form a first layer (AG or CHC), thereby obtaining samples according to Examples 1, 2, 4 to 6 and Comparative Examples 1 to 6. The compositions for forming a first layer were applied so that the film thickness of the first layer (antiglare layer) after curing would be the thickness shown in Table 4.

[0070] Examples 3 and 4 Compositions for forming a first layer were prepared with the compositions listed in Tables 1 and 2. Compositions for forming a second layer were prepared with the compositions listed in Table 3. The compositions for forming the first layer and the second layer were diluted with a solvent to concentrations suitable for coating. The first layer composition was applied to one surface of a 40 μm-thick triacetyl cellulose (TAC) film, dried, and then polymerized and cured by UV irradiation to form a first layer (AG). The first layer composition was applied so that the first layer (antiglare layer) would have a thickness listed in Table 4 after curing. Next, the second layer composition was applied onto the formed first layer, dried, and then polymerized and cured by UV irradiation to form a second layer (LR), thereby obtaining samples according to Examples 3 and 4. The second layer composition was applied so that the second layer (low refractive index layer) would have a thickness of 120 nm after curing.

[0071] The compositions of the coating fluids of the examples and comparative examples are shown in Tables 1 to 3. The proportions shown in Tables 1 to 3 are in mass %.

[0072] [Table 1]

[0073] [Table 2]

[0074] [Table 3]

[0075] The samples according to each of the examples and comparative examples were evaluated as follows.

[0076] [Surface uneven shape] Using a non-contact surface / layer cross-sectional shape measurement system (Vertscan VS1330, Hitachi Systems, Ltd.), three-dimensional data of the uneven shape of the outermost surface of each sample was measured using the optical interference method. The measurement conditions were as follows: <Optical conditions> Camera: Sony HR-50 1 / 3 inch Camera Speed: 1.0X Objective lens magnification: 10XDI (10x) Imaging lens (barrel): 0.5x Zoom lens: 1x Light source / wavelength filter: 520nm ND filter: Not used A-Stop (Aperture Stop): Not used (fully open) F-Stop (field aperture): Not used (fully open) <Measurement conditions> Measuring device: Piezo Measurement mode: Phase Scan speed: 4μm / sec Field of view size: 640 x 480 pixels Scan range: 10μm to -10μm Effective pixels: 50% Average number of times: 1 Measurement range: 701.826μm x 936.116μm (automatically determined by setting the objective lens to 10XDI (10x magnification))

[0077] The raw profile data (three-dimensional height data of unevenness) obtained by the measurement was converted and analyzed using the analysis software (VS-Viewer10, Hitachi High-Tech Corporation) attached to the measuring device to obtain the arithmetic mean height Sa, the number of convexities whose height from the average plane is Sa or more, and the cross-sectional area of ​​the convexities cut at a plane parallel to the average plane and having a height Sa from the average plane of 150 μm. 2 The number of convex portions less than 1000 was calculated. The specific settings for the analysis software are as follows:

[0078] First, based on the following conversion conditions, processing was performed in the order of filtering, surface correction, and interpolation. Note that filtering is a process for removing noise components from the measurement data, surface correction is a process for removing the tilt of the sample, and interpolation is a process for predicting and interpolating parts where measurements could not be obtained due to optical interference during measurement using surrounding data. <Conversion conditions> ·filter Type: Median (3x3) Boundary processing: Object expansion and edge interpolation Surface correction: 4th order Interpolation: Fully interpolated

[0079] Using the ISO parameter function of the analysis software, the arithmetic mean height Sa was calculated under the following processing conditions. <Processing conditions> S-Filter: Automatic (value automatically set according to the objective lens, 0.455 μm in the examples and comparative examples) Regular probability paper Number of divisions: Any Calculation range upper limit: Any Calculation range value: Any Parameters: Select "Height Parameters" Output: Select "Parameter List"

[0080] The data after conversion processing under the above conversion conditions was subjected to Fourier transform. Short wavelength components were extracted from the obtained spectral data using a bandpass filter, and then the extracted spectral data was subjected to inverse Fourier transform to obtain an analysis image. The Fourier transform conditions are as follows: <Fourier transform conditions> Analysis: Frequency filtering Filter: Bandpass filter 0.8μm~50μm Output: Spectral image and analysis image (however, the spectral image can be omitted)

[0081] The analysis image obtained by inverse Fourier transform was analyzed using the particle analysis function (protrusion analysis) of the analysis software attached to the measurement device. The number of all protrusions shown in the analysis results was taken as the number of protrusions whose height from the average plane was equal to or greater than the arithmetic mean height Sa. In addition, of all protrusions shown in the analysis results, the number of protrusions whose area (cross-sectional area on the plane at the height threshold) was 150 μm 2 The number of convex portions that are less than 150 μm2 is counted, and the cross-sectional area of ​​the convex portions cut along a plane parallel to the average plane and having a height Sa from the average plane is 150 μm2. 2 The number of convex portions less than 1 / 2 was used. <Particle analysis conditions> ·Analysis: Sudden analysis Image correction: None Processing: The height threshold is calculated using the arithmetic mean height Set Sa Target determination: Set all particles to be analyzed Histogram: Optional Output: Select "Analysis Image", "Particle Histogram" and "Parameter List"

[0082] [Transparent image clarity] The transmitted image clarity was measured in accordance with JIS K 7374:2007 using an image clarity measuring instrument (ICM-1T, Suga Test Instruments Co., Ltd.) in transmission mode with an optical comb width of 0.5 mm.

[0083] [Glare resistance] The uncoated side of each sample was attached to a glass plate (0.8–1.0 mm thick) using a transparent adhesive. A black matrix with a specified resolution was placed on an LED light box, and the sample, with the glass plate attached to the black matrix, was placed so that the glass plate was in contact with the black matrix. With the LED light box turned on, the glass-attached sample was rotated and observed from directly above, 30 cm away, and the presence or absence of glare was judged visually. Glare observations were made multiple times while increasing the resolution of the black matrix (increasing the ppi value). The maximum resolution (highest ppi value) at which glare was not visually observed was used as the glare resistance score. A score of 210 ppi or higher was considered to be good glare resistance.

[0084] [Anti-glare] The uncoated side of each sample was attached to a black acrylic plate (hereinafter referred to as "blackboard") using a transparent adhesive. With the coated side of the blackboard-attached sample facing up, a three-wavelength fluorescent lamp installed 1 m away was turned on. The sample surface was observed from a direction at 20° to the perpendicular line drawn from the three-wavelength fluorescent lamp to the coated surface of the blackboard-attached sample, and the anti-glare properties were evaluated according to the following criteria. A rating of ○ or higher was deemed to indicate good anti-glare properties. ◎: No reflections are observed or only slight reflections are observed 〇: Reflections are slightly visible ×: Reflections are clearly visible

[0085] Table 4 shows the evaluation results.

[0086] [Table 4]

[0087] As shown in Table 1, the antiglare films according to Examples 1 to 6 all satisfied the condition (A) above for the number of convex portions having a height of Sa or more from the average plane. In addition, the antiglare films according to Examples 1 to 6 all satisfied the condition (A) above for the number of convex portions having a height of Sa or more from the average plane. In addition, the cross-sectional area of ​​the convex portions cut in a plane parallel to the average plane and having a height of Sa from the average plane was 150 μm 2 The number of convex portions was less than 0.01, which satisfied the above condition (B). All of the anti-glare films according to Examples 1 to 6 were excellent in both anti-glare properties (anti-reflection properties) and anti-glare properties at a resolution of 210 ppi or more. This confirms that by satisfying the above condition (A) or (B), it is possible to realize an anti-glare film that can achieve both anti-glare properties and anti-glare properties even when used in a high-resolution image display device with a resolution of 210 ppi or more.

[0088] The optical film according to Comparative Example 1 was a clear hard-coated film having a hard-coated layer that did not contain fine particles, and therefore had a high level of surface smoothness and an extremely small number of convex portions that satisfied the above conditions (A) and (B). The optical film according to Comparative Example 1 had a smooth surface and did not produce a lens effect like an anti-glare layer, and therefore had high transmitted image clarity and excellent anti-glare properties, but did not have sufficient unevenness on the outermost surface that scatters incident light, and therefore had insufficient anti-glare properties (anti-reflection properties).

[0089] The optical film according to Comparative Example 2 does not contain an organic filler, but has a hard coat layer that contains organosilica sol. Because the hard coat layer contains a large amount of organosilica sol, surface irregularities are formed, and the above conditions (A) and (B) are not satisfied. The optical film according to Comparative Example 2 does not contain an organic filler and does not produce a lens effect like an anti-glare layer, so it had high transmitted image clarity and excellent anti-glare properties. However, because the outermost surface does not have a sufficient irregular shape that scatters incident light, its anti-glare properties (anti-reflection properties) were insufficient.

[0090] The antiglare films of Comparative Examples 3 and 4 both had sufficient antiglare properties (anti-reflection properties), but the surface irregularities did not satisfy the above conditions (A) and (B). This is thought to be because the amount of organic filler added was small, which reduced the number of convex portions formed on the surface of the antiglare layer. Therefore, the anti-glare properties were insufficient, and the films were not suitable for use as anti-reflection films for high-resolution image display devices with a resolution of 210 ppi or more.

[0091] The antiglare films of Comparative Examples 5 and 6 both had high antiglare properties (anti-reflection properties), but the surface irregularities did not satisfy the above conditions (A) and (B). This is thought to be because the number of convex portions formed on the surface of the antiglare layer was reduced due to the small amount of organic filler (when the addition amount is the same, the larger the particle size of the organic filler, the fewer the number of particles). Furthermore, in Comparative Examples 5 and 6, the number of convex portions formed was also thought to be reduced due to the increased number of organic fillers that sank into the antiglare layer due to the thick film thickness of the antiglare layer. Therefore, the anti-glare properties were insufficient, and the films were not suitable for use as anti-reflection films for high-resolution image display devices with a resolution of 210 ppi or more. [Industrial Applicability]

[0092] The present invention can be used as an antiglare film to be provided on the outermost surface of an image display device. [Explanation of symbols]

[0093] 1. Anti-glare film 2 Transparent base material 3 Anti-glare layer 4 Low refractive index layer

Claims

1. An antiglare film comprising at least one antiglare layer laminated on a transparent substrate and having an uneven surface on the outermost surface, An antiglare film, characterized in that the number of convex portions having an arithmetic mean height Sa or more present on the outermost surface, as measured by a light interference method, is 600 or more per 701.826 × 936.116 μm2. Here, the number of convex portions is a value calculated by measuring three-dimensional data of the uneven shape of the outermost surface of the antiglare film by an optical interference method, filtering, surface correction, and interpolation processing of the three-dimensional height data obtained by the measurement, then performing a Fourier transform, extracting short wavelength components from the obtained spectral data using a 0.8 to 50 μm bandpass filter, then performing an inverse Fourier transform on the extracted spectral data to obtain an analysis image, and analyzing the analysis image.

2. An antiglare film comprising at least one antiglare layer laminated on a transparent substrate and having an uneven surface on the outermost surface, When the convex portions constituting the concave-convex shape are cut along a plane parallel to the average plane of the concave-convex shape and having a height from the average plane equal to the arithmetic mean height Sa, the cross-sectional area is 150 μm ２ An antiglare film characterized in that the number of convex portions that are less than 480 per 701.826 × 936.116 μm 2. Here, the number of convex portions is a value calculated by measuring three-dimensional data of the uneven shape of the outermost surface of the antiglare film by an optical interference method, filtering, surface correction, and interpolation processing of the three-dimensional height data obtained by the measurement, then performing a Fourier transform, extracting short wavelength components from the obtained spectral data using a 0.8 to 50 μm bandpass filter, then performing an inverse Fourier transform on the extracted spectral data to obtain an analysis image, and analyzing the analysis image.

3. 3. The antiglare film according to claim 1, wherein the transmitted image clarity measured using a 0.5 mm optical comb is 92% or less.

4. The antiglare film according to claim 1 or 2, further comprising a low refractive index layer on the antiglare layer.

5. A display device comprising the antiglare film according to claim 1 or 2.

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