Anti-glare film and image display device using same

Abstract

Provided are: an anti-glare film which has both anti-glare properties and flash resistance even when used in a high-definition image display device; and an image display device which uses the anti-glare film. Provided is an anti-glare film in which at least one or more anti-glare layers are laminated on a transparent substrate and which has an uneven shape on the outermost surface, the anti-glare film being characterized in that the number of protrusions 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 measured area.

Description

Technical Field

[0001] The present invention relates to an antiglare film for reducing reflection of external light and an image display device using the antiglare film. Background Art

[0002] An antiglare film (also referred to as an anti-glare (AG) film) has an antiglare layer in which inorganic or fillers are dispersed in a resin layer on a transparent substrate. The antiglare film scatters surface reflected light through the uneven shape on the outermost surface, blurs the image of the incident external light, and thus improves visibility. Compared with an antireflection film that does not have unevenness on the outermost surface but uses light interference to prevent reflection, the antiglare film has less incidence of images such as people or backgrounds. Therefore, when used in an image display device, the displayed image can be clearly recognized.

[0003] In recent years, with the high definition of image display devices, improvement in the flashiness of the antiglare film has been required. For example, Patent Document 1 describes an antiglare film in which, by making the three-dimensional arithmetic mean roughness of the antiglare layer surface satisfy a predetermined condition, even when used in a high-definition image display device, flash can be suppressed and a decrease in contrast can be suppressed.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent No. 7192777 Gazette Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] The antiglare property of the antiglare film can be improved by increasing the number of unevenness on the outermost surface or increasing the unevenness size. However, due to an increase in the lens effect caused by the uneven shape on the outermost surface, the flash resistance deteriorates. That is, in the antiglare film, there is a trade-off relationship between the antiglare property obtained by the uneven shape on the outermost surface and the flash resistance.

[0009] Therefore, an object of the present invention is to provide an antiglare film that can have both antiglare property and flash resistance even when used in a high-definition image display device, and an image display device using the antiglare film.

[0010] Means for Solving the Problems

[0011] The antiglare film according to one embodiment of the present invention is characterized in that at least one or more antiglare layers are laminated on a transparent substrate, has an uneven shape on the outermost surface, and the number of convex portions having an arithmetic mean height Sa or more present on the outermost surface measured by a light interference method is 600 or more per measurement area.

[0012] Other embodiments of the present invention relate to an antiglare film characterized in that at least one layer or more of antiglare layers are laminated on a transparent substrate, and the outermost surface has an uneven shape. When the convex portions are cut by a plane parallel to the average plane of the uneven shape and at a height from the average plane equal to the arithmetic mean height Sa, the cross-sectional area is less than 150 μm 2 The number of convex portions is 480 or more per measurement area.

[0013] The display device according to the present invention includes the antiglare film according to any one of the above.

[0014] Effects of the Invention

[0015] According to the present invention, it is possible to provide an antiglare film that can achieve both antiglare properties and flash resistance even when used in a high-definition image display device, and an image display device using the antiglare film. Description of the Drawings

[0016] Figure 1 is a cross-sectional view schematically showing an example of the antiglare film according to the embodiment.

[0017] Figure 2 is a cross-sectional view schematically showing another example of the antiglare film according to the embodiment.

[0018] Description of the Reference Numerals

[0019] 1 Antiglare film

[0020] 2 Transparent substrate

[0021] 3 Antiglare layer

[0022] 4 Low refractive index layer Detailed Embodiments

[0023] Figure 1 is a cross-sectional view schematically showing an example of the antiglare film according to the embodiment.

[0024] 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 referred to as an "AG film") that scatters incident light through the fine uneven shape on the surface of the antiglare layer 3 to suppress the intrusion of external light.

[0025] ​​The transparent substrate 2 is a film serving as the base of the antiglare film 11 and is formed of a material having excellent visible light transmittance. As the material for forming the transparent substrate 2, the following can be used: 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; transparent resins or inorganic glasses such as polyimide, polyarylate, polycarbonate, triacetyl cellulose, polyacrylate, polyvinyl alcohol, polyvinyl chloride, cycloolefin copolymer, norbornene-containing resin, polyethersulfone, and polysulfone. The thickness of the transparent substrate 2 is not particularly limited, and it is preferably set to 10 to 200 μm.

[0026] In order to improve the adhesion to other laminated layers, the surface of the transparent substrate 2 can be subjected to a surface modification treatment. Examples of the surface modification treatment include: alkali treatment, corona treatment, plasma treatment, sputtering treatment, coating with a surfactant or a silane coupling agent, Si evaporation coating, etc.

[0027] The antiglare layer 3 is a functional layer forming the fine concavo-convex shape on the outermost surface of the antiglare film 11 and contains fine particles (represented by circles in the drawings). The film thickness of the antiglare layer 3 is not particularly limited, and it is preferably set to 1.3 to 5.0 μm.

[0028] The antiglare layer 3 is formed by coating a coating liquid containing an active energy ray-curable compound and fine particles (organic fillers) on the transparent substrate 2 and curing the coating film.

[0029] As the active energy ray-curable compound, for example, monofunctional, bifunctional, or trifunctional or higher (meth)acrylate monomers can be used. It should be noted that 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 also contain fluorine.

[0030] 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, tert-butyl (meth)acrylate, glycidyl (meth)acrylate, acryloylmorpholine, N-vinylpyrrolidone, tetrahydrofurfuryl acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 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, phosphoric acid (meth)acrylate, ethylene oxide-modified phosphoric acid (meth)acrylate, phenoxy (meth)acrylate, ethylene oxide-modified phenoxy (meth)acrylate, propylene 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 hydrogen phthalate, 2-(meth)acryloyloxypropyl hydrogen phthalate, 2-(meth)acryloyloxypropyl hexahydrophthalate, 2-(meth)acryloyloxypropyl tetrahydrophthalate, dimethylaminoethyl (meth)acrylate, trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropropyl (meth)acrylate, and adamantane derivatives such as adamantyl acrylate, which is a monovalent mono(meth)acrylate derived from 2-adamantane and adamantanediol, and other monovalent mono(meth)acrylates.

[0031] Examples of difunctional (meth)acrylates include: 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, neopentyl glycol hydroxypivalate di(meth)acrylate, and other di(meth)acrylates.

[0032] Examples of the (meth)acrylate having 3 or more functional groups 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 glycerol tri(meth)acrylate; trifunctional (meth)acrylate compounds such as pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, and bis(trimethylolpropane) tri(meth)acrylate; polyfunctional (meth)acrylate compounds having 3 or more functional groups such as pentaerythritol tetra(meth)acrylate, bis(trimethylolpropane) tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, bis(trimethylolpropane) penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and bis(trimethylolpropane) hexa(meth)acrylate; and polyfunctional (meth)acrylate compounds in which a part of these (meth)acrylates is substituted with an alkyl group or ε-caprolactone.

[0033] In addition, a urethane (meth)acrylate can also be used as the polyfunctional monomer. Examples of the urethane (meth)acrylate include urethane (meth)acrylates obtained by reacting a product obtained by reacting an isocyanate monomer or prepolymer with a polyester polyol with a (meth)acrylate monomer having a hydroxyl group.

[0034] Examples of the urethane (meth)acrylate 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, dipentaerythritol pentaacrylate isophorone diisocyanate urethane prepolymer, and the like.

[0035] One kind of the above polyfunctional monomers can be used, or two or more kinds can be used in combination. In addition, the above polyfunctional monomers can be monomers or oligomers partially polymerized in the coating liquid.

[0036] Particles (organic fillers) are materials that mainly form fine irregularities on the surface of the antiglare layer 3 and impart the function of diffusing external light. As the organic filler, resin particles composed of a light-transmitting resin material such as acrylic resin, polystyrene resin, styrene-(meth)acrylate copolymer, polyethylene resin, epoxy resin, silicone resin, polyvinylidene fluoride, and polyvinyl fluoride resin can be used. In order to adjust the refractive index and the dispersion of the resin particles, two or more types of resin particles having different materials (refractive indices) can be mixed and used. The average particle diameter of the organic filler is preferably 0.5 to 5.5 μm. When the average particle diameter of the organic filler exceeds 5.5 μm, if the mass of the organic filler is constant, the number of particles is smaller than when the average particle diameter of the organic filler is 5.5 μm or less, so the number of convex portions formed becomes smaller, and the flash resistance tends to decrease. Although the refractive index of the organic filler also depends on the refractive index of the binder resin (energy ray-curable resin), it is preferably 1.495 to 1.595. In addition, although the blending amount of the organic filler also depends on the particle diameter, it is preferably 2 to 20% by mass of the total solid content of the antiglare layer-forming composition.

[0037] The antiglare layer-forming composition may further contain inorganic fine particles. The inorganic fine particles added to the antiglare layer-forming composition are preferably nanoparticles having an average particle diameter of 10 to 200 nm.

[0038] Inorganic fine particles are materials mainly used to regulate the sedimentation or aggregation of fine particles (organic fillers) in the antiglare layer 3. As the inorganic fine particles, silica fine particles, metal oxide fine particles, various mineral fine particles, etc. can be used. As the silica fine particles, for example, colloidal silica or silica fine particles surface-modified with reactive functional groups such as (meth)acryloyl group can be used. As the metal oxide fine particles, for example, alumina, zinc oxide, tin oxide, antimony oxide, indium oxide, titanium dioxide, zirconium oxide, etc. can be used. As the mineral fine particles, for example, mica, synthetic mica, vermiculite, montmorillonite, ferro montmorillonite, bentonite, beidellite, saponite, hectorite, stevensite, nontronite, magadiite, illite, kanemite, layered titanic acid, smectite, synthetic smectite, etc. can be used. The mineral fine particles can be either natural products or synthetic products (including substitutes and derivatives), or a mixture of the two can be used. Among the mineral fine particles, layered organic clay is more preferably used. Layered organic clay refers to a substance obtained by introducing organic onium ions into the interlayer of swellable clay. The organic onium ions are not limited as long as they can be organicized by the cation exchangeability of the swellable clay. As the mineral fine particles, when using layered organic clay minerals, the above-mentioned synthetic smectite can be preferably used. Synthetic smectite has the functions of increasing the viscosity of the composition for forming the antiglare layer, inhibiting the sedimentation of resin particles and inorganic fine particles, and adjusting the uneven shape of the surface of the optical functional layer.

[0039] In order to cure the composition for forming the antiglare layer by ultraviolet irradiation, a polymerization initiator can also be added. As the polymerization initiator, a polymerization initiator that generates free radicals by ultraviolet irradiation can be used. As the polymerization initiator, free radical polymerization initiators such as acetophenone-based, benzophenone-based, thioxanthone-based, benzoin, benzoin methyl ether, acylphosphine oxide, etc. can be used. As the polymerization initiator, for example, 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, benzoyl, benzoin, benzoin methyl ether, benzoin ethyl ether, p-chlorobenzophenone, p-methoxybenzophenone, Michler's ketone, acetophenone, 2-chlorothioxanthone, etc. can be used. Among these, one kind can be used alone, or two or more kinds can be used in combination.

[0040] In addition, in the composition for forming the antiglare layer, as components for improving antifouling properties, it is preferable to add antifouling agents, leveling agents, oleophobic agents, hydrophobic agents, and fingerprint adhesion preventives. As these additives, fluorine-containing compounds or silicone compounds can be preferably used. By adding antifouling compounds to the antiglare layer 3 as the outermost layer, the fingerprint wipeability can be further improved. In addition, various additives such as antistatic agents, defoaming agents, antioxidants, ultraviolet absorbers, infrared absorbers, colorants, light stabilizers, polymerization inhibitors, and photosensitizers can also be added as needed.

[0041] In addition, a solvent can also be added to the composition for forming the antiglare layer as needed. As the solvent, one or more of the following can be mixed and used: alcohols such as methanol, ethanol, 1-propanol, 2-propanol, butanol, isopropanol, 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; diols such as ethylene glycol, propylene glycol, and hexanediol; 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; N-methylpyrrolidone; and dimethylformamide.

[0042] Figure 2 It is a cross-sectional view schematically showing another example of the optical film according to the embodiment.

[0043] 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 referred to as an "AGLR film") that suppresses the entry and reflection of external light by the scattering and optical interference of incident light caused by the fine irregularities on the outermost surface.

[0044] As the transparent substrate 2, a film made of the above-described forming material can be used, and the antiglare layer 3 can be formed by coating the above-described composition for forming the antiglare layer on one surface of the transparent substrate 2 and drying and curing it.

[0045] The low refractive index layer 4 has a refractive index lower than that of the underlying antiglare layer 3 and is a functional layer that suppresses reflection by optical interference. The film thickness of the low refractive index layer 4 is not particularly limited, and is preferably 100 to 120 nm.

[0046] The low refractive index layer 4 can be formed by coating a composition containing a radiation curable compound on the surface of the antiglare layer 3 and curing the coating film. In order to adjust the refractive index, the low refractive index layer 4 can also contain low refractive index fine particles.

[0047] As the low refractive index particles, for example, particles such as LiF, MgF2, NaF, AlF3, Na3AlF6, SiO2, etc. can be used. As the silica particles, silica particles having voids inside can be preferably used. The silica particles having voids inside can make the void part have the refractive index of air (about 1), so it is beneficial to reduce the refractive index of the low refractive index layer 4. Specifically, porous silica particles, silica particles with a shell structure can be used. It should be noted that low refractive index particles are not necessarily required. When the refractive index after curing the active energy ray curable compound is lower than the refractive index of the antiglare layer 3, the low refractive index particles can also be omitted.

[0048] As the active energy ray curable compound, the polymerizable compounds described in the antiglare layer can be used. In addition, the above-mentioned polymerization initiator and solvent can also be appropriately added to the composition for forming the low refractive index layer.

[0049] Since the low refractive index layer 4 is the outermost functional layer, in the composition for forming the low refractive index layer, as components for improving antifouling properties, an antifouling agent, a leveling agent, an oleophobic agent, a hydrophobic agent, and an anti-fingerprint adhesion agent are preferably added. As these additives, fluorine-containing compounds or silicone compounds can be preferably used. In addition, various additives such as an antistatic agent, an antifoaming agent, an antioxidant, an ultraviolet absorber, an infrared absorber, a coloring material, a light stabilizer, a polymerization inhibitor, and a photosensitizer can also be added as needed.

[0050] 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 absorption layer, an ultraviolet absorption layer, and a complementary color layer can also be laminated between the transparent substrate 2 and the antiglare layer 3.

[0051] The coating method of the above-mentioned composition for forming the antiglare layer and the composition for forming the low refractive index layer is not particularly limited. For example, a spin coater, a roll coater, an inverse 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, etc. can be used for coating.

[0052] Here, the details of the surface uneven shape of the antiglare film according to the present embodiment will be described. The antiglare film according to the present embodiment satisfies at least one of the following conditions (A) and (B).

[0053] Condition (A):

[0054] The number of convex portions existing on the outermost surface and having a height of arithmetic mean height Sa or more is 600 or more per measurement area.

[0055] 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 it with the analysis software of the measuring device. The measurement area is 701.826 × 936.116 μm when measured under the measurement conditions of the following examples. 2 (≈0.662 m 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 value of the absolute values of the heights of the convex portions from the average plane with respect to the average plane of all the unevenness present in the measurement area.

[0056] In the present 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 following examples. However, when the number of convex portions having a height equal to or greater than Sa is expressed as the number per area different from the measurement area of the present embodiment, it is sufficient that the number of convex portions converted to the number per measurement area of the present embodiment is 600 or more.

[0057] When the number of convex portions specified in the above condition (A) is 600 or more per measurement area, high antiglare properties can be ensured, and even when used for a high-definition image display device such as 210 ppi or more, flash can be reduced. 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 related to flash resistance, and as it increases, the flash resistance improves. There is no particular limitation on the upper limit of the number of convex portions present on the outermost surface and having a height equal to or greater than the arithmetic mean height Sa, and it may be 2000 or less per measurement area, or it may be 1850 or less per measurement area.

[0058] Condition (B):

[0059] When the convex portion is cut by 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 number of convex portions having a cross-sectional area of less than 150 μm 2 is 480 or more per measurement area.

[0060] When the cross-sectional area of the convex portion when cut by a plane having a height from the average plane equal to the arithmetic mean height Sa is less than 150 μm 2 is a value obtained by measuring the outermost surface of the antiglare film using an optical interference method and analyzing it with the analysis software of the measuring device. The measurement method of the measurement area and the arithmetic mean height Sa is the same as that described in condition (A).

[0061] In the present 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 following examples. However, when the cross-sectional area cut by a plane having a height from the average plane equal to the arithmetic mean height Sa is less than 150 μm 2 and the number of convex portions is expressed as the number per area different from the measurement area of the present embodiment, it is sufficient that the value obtained by converting the number per area of this difference into the number per measurement area of the present embodiment is 480 or more.

[0062] When the number of convex portions specified in the above condition (B) is 480 or more per measurement area, high anti-glare properties can be ensured, and even when used in a high-definition image display device such as 210 ppi or more, flash can be reduced. When the cross-sectional area cut by a plane having a height from the average plane equal to the arithmetic mean height Sa is less than 150 μm 2 the number of convex portions is a parameter related to flash resistance, and as it increases, the flash resistance improves. Regarding the upper limit of the number of convex portions having a cross-sectional area cut by a plane having a height from the average plane equal to the arithmetic mean height Sa less than 150 μm 2 there is no particular limitation, and it can be 2000 or less per measurement area, or can be 1700 or less per measurement area.

[0063] The number of convex portions specified in the above conditions (A) and (B) can be controlled, for example, by adjusting the particle diameter or addition amount of the filler added to the anti-glare layer 3, the amount of the additive, the film thickness of the anti-glare layer 3, and the aggregation state of the filler in the film formation process.

[0064] In addition, the transmission image clarity of the anti-glare film according to the present embodiment is preferably 92% or less. The transmission image clarity is a value measured using an optical comb with a width of 0.5 mm in accordance with JIS K 7374 (2007). When the transmission image clarity of the anti-glare film exceeds 92%, the effect of scattering light on the outermost surface is weakened, and the entry of external light cannot be sufficiently reduced, so it is not preferable.

[0065] In addition, preferably, when observing a light source in a state where the anti-glare film according to the present embodiment is overlapped on a black matrix with a fineness of 210 ppi or more, no flash is visually recognized. When flash is visually recognized when observing a light source in a state where the anti-glare film is overlapped on a black matrix with a fineness less than 210 ppi, it is not suitable for use as an anti-reflection film for recent high-definition image display devices.

[0066] The antiglare film according to this embodiment can be used by being adhered to the outermost surface of an image display panel such as a liquid crystal panel or an organic EL panel to constitute an image display device. A touch panel may also be provided between the antiglare film and the image display panel. Since the antiglare film according to this embodiment is excellent in antiglare property and flash resistance, it is suitable as an optical film for an image display device, particularly for the outermost surface of a high-definition image display device having 210 ppi or more.

[0067] Examples

[0068] Hereinafter, examples in which the present invention has been specifically implemented will be described.

[0069] (Composition for forming the first layer)

[0070] An antiglare layer (AG) or a transparent hard coat layer (CHC) is formed as the first layer on a transparent substrate. The materials for the composition for forming the first layer are as follows.

[0071] 1. Actinic energy ray curable resin

[0072] Light Acrylate PE-3A (trade name), KYOEISHA CHEMICAL CO., LTD., Pentaerythritol triacrylate

[0073] 2. Photoinitiator

[0074] Omnirad (registered trademark) 184 (trade name), IGM Resins B.V., 1-Hydroxycyclohexyl-phenyl ketone

[0075] 3. Organic filler (fine particles)

[0076] (1) Resin particle 1: diameter 1.5 μm, refractive index 1.495

[0077] (2) Resin particle 2: diameter 2.0 μm, refractive index 1.516

[0078] (3) Resin particle 3: diameter 3.4 μm, refractive index 1.564

[0079] (4) Resin particle 4: diameter 3.5 μm, refractive index 1.515

[0080] (5) Resin particle 5: diameter 3.5 μm, refractive index 1.590

[0081] (6) Resin particle 6: diameter 3.5 μm, refractive index 1.564

[0082] (7) Resin particle 7: diameter 5.3 μm, refractive index 1.544

[0083] 4. Tackifier

[0084] Sumecton SAN (trade name), Kunimine Industries Co., Ltd., organically synthesized hectorite

[0085] 5. Levelling agent

[0086] Megafac (registered trademark) F565 (trade name), DIC Corporation

[0087] 6. Additive

[0088] MEK-ST-40 (trade name), Nissan Chemical Industries, Ltd., silica sol

[0089] 7. Solvent

[0090] Toluene

[0091] (Composition for forming the second layer)

[0092] In Examples 3 and 4, a low refractive index layer (LR) with a film thickness of 120 nm was formed on the antiglare layer as the second layer. The materials for the composition for forming the second layer are shown below.

[0093] 1. Actinic energy ray curable resin

[0094] (1) Light Acrylate PE-3A (trade name), Kyoeisha Chemical Co., Ltd., pentaerythritol triacrylate (denoted as "PE-3A" in the table)

[0095] (2) Fluoroacrylate, Kyoeisha Chemical Co., Ltd.

[0096] 2. Photopolymerization initiator

[0097] Omnirad (registered trademark) 184 (trade name), IGM Resins B.V., 1-hydroxycyclohexyl-phenyl ketone

[0098] 3. Hollow silica particles

[0099] Porous silica particles (diameter 75 nm), JGC Catalysts and Chemicals Ltd.

[0100] 4. Levelling agent

[0101] Megafac RS-75 (trade name), DIC Corporation

[0102] 5. Solvent

[0103] meso-Isobutyl ketone

[0104] (Examples 1, 2, 4 to 6 and Comparative Examples 1 to 6)

[0105] Prepare the first-layer forming composition having the compositions described in Tables 1 and 2. It should be noted that the first-layer forming composition is diluted with a solvent to a concentration suitable for coating. After coating the first-layer forming composition on one surface of a triacetyl cellulose (TAC) film with a thickness of 40 μm and drying it, the coating film is polymerized and cured by ultraviolet irradiation to form the first layer (AG or CHC), and the samples according to Examples 1, 2, 4 to 6 and Comparative Examples 1 to 6 are obtained. It should be noted that the first-layer forming composition is coated in such a manner that the film thickness of the cured first layer (anti-glare layer) becomes the film thickness described in Table 4.

[0106] (Examples 3 and 4)

[0107] Prepare the first-layer forming composition having the compositions described in Tables 1 and 2. Further, prepare the second-layer forming composition having the composition described in Table 3. It should be noted that the first-layer forming composition and the second-layer forming composition are diluted with a solvent to a concentration suitable for coating. After coating the first-layer forming composition on one surface of a triacetyl cellulose (TAC) film with a thickness of 40 μm and drying it, the coating film is polymerized and cured by ultraviolet irradiation to form the first layer (AG). It should be noted that the first-layer forming composition is coated in such a manner that the film thickness of the cured first layer (anti-glare layer) becomes the film thickness described in Table 4. Then, after coating the second-layer forming composition on the formed first layer and drying it, the coating film is polymerized and cured by ultraviolet irradiation to form the second layer (LR), and the samples according to Examples 3 and 4 are obtained. It should be noted that the second-layer forming composition is coated in such a manner that the film thickness of the cured second layer (low refractive index layer) becomes 120 nm.

[0108] Tables 1 to 3 show the compositions of the coating liquids for each example and each comparative example. The ratios shown in Tables 1 to 3 are in mass %.

[0109] [Table 1]

[0110]

[0111] [Table 2]

[0112]

[0113] [Table 3]

[0114]

[0115] Evaluate the samples according to each example and each comparative example as follows.

[0116] [Surface uneven shape]

[0117] Using a non-contact surface / layer profile shape measurement system (VertScan VS1330, Hitachi Systems, Ltd.), three-dimensional data of the uneven shape of the outermost surface of each sample was measured by means of optical interference. The measurement conditions are as follows.

[0118] <Optical conditions>

[0119] · Camera: Sony Corporation HR-50 1 / 3 inch

[0120] · Shooting speed: 1.0X

[0121] · Objective lens magnification: 10XDI (10 times)

[0122] · Imaging lens (lens barrel): 0.5 times

[0123] · Zoom lens: 1 time

[0124] · Light source / wavelength filter: 520 nm

[0125] · ND filter: Not used

[0126] · A-Stop (aperture diaphragm): Not used (fully open)

[0127] · F-Stop (field diaphragm): Not used (fully open)

[0128] <Measurement conditions>

[0129] · Measuring device: Piezoelectric

[0130] · Measurement mode: Phase

[0131] · Scanning speed: 4 μm / sec

[0132] · Field of view size: 640 × 480 pixels

[0133] · Scanning range: 10 μm to -10 μm

[0134] · Effective pixel number: 50%

[0135] · Average number of times: 1 time

[0136] · Measurement range: 701.826 μm × 936.116 μm (automatically determined by setting the objective lens to 10XDI (10 times))

[0137] Using the analysis software (VS-Viewer10, Hitachi High-Tech Corporation) attached to the measuring device, the measured profile raw data (three-dimensional height data of unevenness) is transformed and analyzed to calculate the arithmetic mean height Sa, the number of convex parts with a height above Sa from the average plane, and the cross-sectional area of the convex parts cut by a plane parallel to the average plane and at a height of Sa from the average plane is less than 150 μm 2 The number of convex parts. The specific setting conditions in the analysis software are as follows.

[0138] First, based on the following transformation conditions, the processes of filtering, surface correction, and interpolation are performed in sequence. It should be noted that the filtering process is used to remove noise components from the measurement data, the surface correction process is used to remove the inclination of the sample, and interpolation is a process of predicting and interpolating the parts where measurement values cannot be obtained due to light interference during measurement using surrounding data.

[0139] <Transformation conditions>

[0140] · Filter

[0141] Type: Median (3×3)

[0142] Boundary processing: Expand the object and interpolate the edge part

[0143] · Surface correction: 4 times

[0144] · Interpolation: Complete interpolation

[0145] Using the ISO parameter function of the analysis software, the arithmetic mean height Sa is calculated under the following processing conditions.

[0146] <Processing conditions>

[0147] · S-Filter: Automatic (a value automatically set according to the objective lens, 0.455 μm in the examples and comparative examples)

[0148] · Normal probability paper

[0149] Number of divisions: Arbitrary

[0150] Upper limit of calculation range: Arbitrary

[0151] Value of calculation range: Arbitrary

[0152] Parameter: Select "Height Paramters"

[0153] Output: Select "Parameter list"

[0154] Perform Fourier transform on the data after the transformation process under the above-mentioned transformation conditions. After extracting the short-wavelength components from the obtained spectral data using a band-pass filter, perform inverse Fourier transform on the extracted spectral data to obtain an analysis image. The Fourier transform conditions are as follows.

[0155] <Fourier transform conditions>

[0156] · Analysis: Frequency filtering

[0157] · Filter: Band-pass filter 0.8μm to 50μm

[0158] · Output: Spectral image and analysis image (where the spectral image can be omitted)

[0159] Use the particle analysis function (protrusion analysis) of the analysis software attached to the measuring device to analyze the analysis image obtained by inverse Fourier transform. Set the number of all convex parts shown in the analysis result as the number of convex parts with a height above the arithmetic mean height Sa from the average plane. In addition, count the number of convex parts among all the convex parts shown in the analysis result whose area (cross-sectional area on the plane at the height threshold) is less than 150μm 2 as the number of convex parts whose cross-sectional area cut by a plane parallel to the average plane and at a height of Sa from the average plane is less than 150μm 2

[0160] <Particle analysis conditions>

[0161] · Analysis: Convex analysis

[0162] · Image correction: None

[0163] · Processing: Set the arithmetic mean roughness Sa calculated above as the height threshold

[0164] · Object determination: Set all particles as the analysis objects

[0165] · Histogram: Optional

[0166] · Output: Select "Analysis image", "Particle histogram", and "Parameter list"

[0167] [Transmission image clarity]

[0168] The transmission image clarity is measured according to JIS K 7374:2007 using an imaging property measuring device (ICM-1T, Suga Test Instruments Co., Ltd.) in transmission mode with an optical comb width of 0.5mm.

[0169] [Flash resistance]

[0170] Use a transparent adhesive to stick the non-coated surface of each sample to a flat glass (thickness 0.8-1.0 mm). Place a black matrix with a predetermined fineness on the LED light box, and place the sample pasted on the flat glass on the black matrix so that the flat glass is in contact with the black matrix. When the LED light box is lit, rotate the glass-pasted sample, observe the sample from a position 30 cm away directly above, and determine the presence or absence of flash by visual inspection. While increasing the fineness of the black matrix (increasing the ppi value), perform multiple flash observations, and use the maximum fineness (highest ppi value) at which no flash can be visually detected as the flash resistance score. If the score is 210 ppi or above, it is judged to be good flash resistance.

[0171] [Anti-reflection]

[0172] The non-coated surface of each sample was pasted on a black acrylic plate (hereinafter referred to as "blackboard") using a transparent adhesive. With the coated surface of the blackboard-pasted sample facing upward, a three-wavelength fluorescent lamp set at a position 1m above was lit. The surface of the sample was observed from a direction of 20° relative to the vertical line from the three-wavelength fluorescent lamp falling to the coated surface of the blackboard-pasted sample, and the anti-reflection property was evaluated according to the following criteria. If the evaluation is ○ or above, it is judged that the anti-reflection property (anti-glare property) is good.

[0173] ◎: No reflection is detected at all or only a very small amount is detected

[0174] 0:Slightly confirmed

[0175] ×: Clearly confirmed to be reflected

[0176] The evaluation results are shown in Table 4.

[0177] [Table 4]

[0178]

[0179] As shown in Table 1, in the anti-glare films of Examples 1 to 6, the number of convex portions having a height Sa or more from the average surface all satisfies the above condition (A). In addition, in the anti-glare films of Examples 1 to 6, the cross-sectional area of the convex portions cut along a plane parallel to the average surface and having a height Sa from the average surface is less than 150 μm. 2 The number of convex portions of all satisfy the above condition (B). In the anti-glare films involved in Examples 1 to 6, both the anti-glare property (anti-reflection property) and the flash resistance at a fineness of 210 ppi or more are good. It can be confirmed that by satisfying the above condition (A) or (B), an anti-glare film that can have both anti-glare and flash resistance can be achieved even in the case of a high-definition image display device with a ppi or more.

[0180] The optical film according to Comparative Example 1 is a transparent hard coating film having a hard coating that does not contain fine particles, and thus has high surface smoothness and very few convex portions that satisfy the above conditions (A) and (B). The surface of the optical film according to Comparative Example 1 is smooth and does not produce a lenticular effect like an antiglare layer, and thus has high transmitted image clarity and excellent flash resistance. However, since the concavo-convex shape that scatters incident light on the outermost surface is not sufficiently formed, the antiglare property (anti-reflection property) is insufficient.

[0181] The optical film according to Comparative Example 2 is a hard coating that does not contain an organic filler but contains an organosilica sol. Since the hard coating contains a large amount of organosilica sol, surface irregularities are formed, but 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 lenticular effect like an antiglare layer, and thus has high transmitted image clarity and excellent flash resistance. However, since the concavo-convex shape that scatters incident light on the outermost surface is not sufficiently formed, the antiglare property (anti-reflection property) is insufficient.

[0182] The antiglare films according to Comparative Examples 3 and 4 both have sufficient antiglare property (anti-reflection property), but the surface concavo-convex shape does not satisfy the above conditions (A) and (B). It is considered that this is because the addition amount of the organic filler is small, and thus the number of convex portions formed on the surface of the antiglare layer becomes small. Therefore, the flash resistance is insufficient, and it is not suitable for use as an antireflection film for a high-definition image display device with 210 ppi or more.

[0183] The antiglare films according to Comparative Examples 5 and 6 both have high antiglare property (anti-reflection property), but the surface concavo-convex shape does not satisfy the above conditions (A) and (B). It is considered that this is because the number of organic fillers is small (if the addition amounts are the same, the larger the particle size of the organic filler, the fewer the number of particles), and thus the number of convex portions formed on the surface of the antiglare layer becomes small. In addition, in Comparative Examples 5 and 6, since the film thickness of the antiglare layer is relatively thick, it is considered that even if the number of organic fillers that sink in increases, the number of convex portions formed will decrease. Therefore, the flash resistance is insufficient, and it is not suitable for use as an antireflection film for a high-definition image display device with 210 ppi or more.

[0184] Industrial Applicability

[0185] The present invention can be used as an antiglare film provided on the outermost surface of an image display device.

Claims

1. An antiglare film, wherein, At least one antiglare layer is laminated on a transparent substrate, and the outermost surface has an uneven shape. It is characterized in that The number of convex portions 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.

2. An antiglare film, wherein, At least one antiglare layer is laminated on a transparent substrate, and the outermost surface has an uneven shape. It is characterized in that When cutting the convex portion with a plane parallel to the average plane of the concavo-convex shape and at a height from the average plane equal to the arithmetic mean height Sa, the cross-sectional area is less than 150 μm 2 and the number of convex portions is 480 or more per measurement area.

3. The anti-glare film according to claim 1 or 2, characterized in that, The transmission image sharpness measured using an optical comb of 0.5 mm is 92% or less.

4. The anti-glare film according to claim 1 or 2, characterized in that, When observing a light source in a state where it is overlapped on a black matrix having a fineness of 210 ppi or more, no flash is visually recognized.

5. The antiglare film according to claim 1 or 2, wherein, A low refractive index layer is provided on the antiglare layer.

6. A display device including the antiglare film according to claim 1 or 2.

Images