Optical laminate and image display device using the same

Abstract

This relates to an optical laminate that achieves both fingerprint resistance and anti-glare properties, and an image display device using the same. [Solution] An optical laminate comprising a transparent substrate, a first functional layer having an inorganic fine particle content of 5 to 80% by mass, and a second functional layer having a refractive index lower than that of the first functional layer, laminated in this order, and having an uneven surface, characterized in that it satisfies the following conditions (1) and (2). 6,000 ≤ A ≤ 40,000 (1) 50 ≤ B ≤ 800 (2) (Here, when the spatial frequency f is calculated from the three-dimensional data obtained by measuring the aforementioned uneven shape using the Fast Fourier Transform, A is the average value of the power spectrum intensity in the range of 50 cycles / mm ≤ f ≤ 100 cycles / mm, and B is the average value of the power spectrum intensity in the range of 200 cycles / mm ≤ f ≤ 250 cycles / mm.)

Description

[Technical Field]

[0001] This invention relates to an optical laminate and an image display device using the same. [Background technology]

[0002] Anti-glare (AG) films are constructed by laminating an anti-glare layer, consisting of a resin layer containing fillers, onto a transparent substrate. The uneven surface of the anti-glare layer diffuses reflected light, preventing reflections of external light. Anti-glare low-reflection (AGLR) films are also known, which further suppress reflected light by laminating a low-refractive-index layer (low-reflection (LR) layer) on top of the anti-glare layer of the AG film and utilizing optical interference. AG films and AGLR films (hereinafter collectively referred to as "anti-glare films") are used in a variety of displays.

[0003] Anti-glare films for touch panel displays with anti-reflective properties require not only good optical properties such as AG (anti-glare) but also excellent wipeability for removing fingerprints that adhere during operation.

[0004] For example, Patent Document 1 discloses an anti-glare, anti-reflective film comprising an anti-glare hard coat layer containing particles with an average particle size of 1 to 10 μm, and a low refractive index layer containing inorganic fine particles with an average particle size of 0.001 to 0.2 μm, a photocurable organosilane component, and a fluorovinyl polymer, in that order, which has a haze value of 3 to 20% and an average reflectance of 1.8% or less from 450 nm to 650 nm, and exhibits excellent anti-reflective performance, scratch resistance, and stain resistance.

[0005] Patent Document 2 discloses a surface material for high-definition displays in which an anti-glare layer is provided on a transparent substrate, either alone or via a functional layer, and that when the average spacing of the irregularities on the surface of the anti-glare layer is 20 to 300 μm, the surface energy is 30 to 70 mN / m, and the haze value of the display surface material is 3 to 50%, it can have both an anti-glare function and a function that makes fingerprints adhering to the surface less noticeable, thereby improving the visibility of the display. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 4542663 [Patent Document 2] Japanese Patent Publication No. 2008-96781 [Overview of the project] [Problems that the invention aims to solve]

[0007] Generally, anti-glare films have an uneven surface formed on the anti-glare layer. If the unevenness is large, the anti-fingerprint properties are good, but external scattering increases, resulting in high haze. This makes the screen of the display to which the film is applied appear whiter, blurrier, and less visible. On the other hand, if the unevenness is small, external scattering is reduced, resulting in low haze. This increases the transparency of the screen and improves visibility, but the anti-fingerprint properties are inferior. Thus, achieving both low haze, anti-fingerprint properties, and anti-glare properties simultaneously is difficult, and although various methods have been investigated, there is still room for improvement.

[0008] This invention relates to an optical laminate that achieves both anti-fingerprint and anti-glare properties, and an image display device using the same.

[0009] Furthermore, the present invention relates to an optical laminate that achieves both low haze, anti-fingerprint properties and anti-glare properties, and an image display device using the same. [Means for solving the problem]

[0010] The present invention relates to the following [1] to [2]. [1] An optical laminate comprising a transparent substrate, a first functional layer having an inorganic fine particle content of 5 to 80% by mass, and a second functional layer having a refractive index lower than that of the first functional layer, laminated in this order, and having an uneven surface, characterized in that it satisfies the following conditions (1) and (2). 6,000 ≤ A ≤ 40,000 (1) 50 ≦ B ≦ 800 (2) (Here, the three-dimensional data of the uneven height measured by the optical interference method or the contact method for the uneven shape is converted into first image data with the uneven height as the pixel value, and the first image data is converted into a second image by fast Fourier transform. When calculating the spatial frequency f of the X coordinate of the power spectrum of the image within the range of ±20 Pixel on the positive X axis passing through the origin in the second image, A: The average value of the power spectrum intensity in the range of 50 cycle / mm ≦ f ≦ 100 cycle / mm, B: The average value of the power spectrum intensity in the range of 200 cycle / mm ≦ f ≦ 250 cycle / mm (is) [2] An image display device including the optical laminate described in [1]. [Advantages of the Invention]

[0011] The optical laminate of the present invention has an excellent effect of achieving both fingerprint resistance and antiglare properties.

[0012] In addition, the optical laminate of the present invention has an excellent effect of achieving both fingerprint resistance and antiglare properties with low haze. [Brief Description of the Drawings]

[0013] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of the optical laminate of the present invention. [Figure 2] FIG. 2 is a diagram showing a typical example of the power spectrum in the target direction obtained by analyzing the surface shape of the optical laminate of the present invention. [Figure 3] FIG. 3 is a schematic diagram showing an example of a glare measuring instrument used in reflection antiglare measurement. [Embodiments for Carrying Out the Invention]

[0014] FIG. 1 is a schematic cross-sectional view showing an example of the optical laminate according to the embodiment.

[0015] The optical laminate 10 includes a transparent substrate 1, an antiglare layer (first functional layer) 2 laminated on one surface of the transparent substrate 1, and a low refractive index layer (second functional layer) 3 laminated on the surface of the antiglare layer 2 and having a lower refractive index than the antiglare layer 2. The optical laminate 10 is an optical film (also referred to as an "AGLR film") that suppresses the reflection and intrusion of external light by utilizing the scattering of incident light and optical interference due to the fine irregularities on the outermost surface.

[0016] The transparent substrate 1 is a film that serves as the base of the optical laminate 10 and is formed of a material with excellent visible light transmittance. As the material for forming the transparent substrate 2, 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, polyimide, polyarylate, polycarbonate, triacetyl cellulose, polyvinyl alcohol, polyvinyl chloride, cycloolefin copolymer, norbornene-containing resin, polyethersulfone, polysulfone, and other transparent resins or inorganic glass can be used. The thickness of the transparent substrate 1 is not particularly limited, but it is preferably 10 to 200 μm.

[0017] The surface of the transparent substrate 1 may be subjected to a surface modification treatment in order to improve the adhesion with the antiglare layer 2. Examples of the surface modification treatment include alkali treatment, corona treatment, plasma treatment, sputtering treatment, application of a surfactant or a silane coupling agent, Si deposition, and the like.

[0018] The antiglare layer (first functional layer) 2 is an optical functional layer that forms a fine uneven shape on the outermost surface of the optical laminate 10.

[0019] The antiglare layer 2 is formed by applying a composition containing an active energy ray curable compound and a filler (also referred to as an "antiglare layer forming composition") on one surface of the transparent substrate 1 and curing the coating film.

[0020] Active energy ray curable compounds are resins that polymerize and harden upon irradiation with active energy rays such as ultraviolet light or electron beams. For example, monofunctional, bifunctional, or trifunctional (meth)acrylate monomers 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.

[0021] Examples of monofunctional (meth)acrylate compounds 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, tetrahydrofurfluryl acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and isobornyl (meth)acrylate. Phosphate, 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 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, 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, which has a monovalent mono(meth)acrylate derived from adamantanediol.

[0022] Examples of difunctional (meth)acrylate compounds 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 hydroxypivalate neopentyl glycol di(meth)acrylate.

[0023] Examples of trifunctional (meth)acrylate compounds include trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, tris-2-hydroxyethyl isocyanurate tri(meth)acrylate, glycerin tri(meth)acrylate, and other trifunctional (meth)acrylate compounds such as pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, and ditrimethylolpropane tri(meth)acrylate. Examples include polyfunctional (meth)acrylate compounds with three or more functions, 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 some of these (meth)acrylates are substituted with alkyl groups or ε-caprolactone.

[0024] Furthermore, urethane (meth)acrylates can also be used as active energy ray curable compounds. Examples of urethane (meth)acrylates include those obtained by reacting a product obtained by reacting a polyester polyol with an isocyanate monomer or prepolymer with a hydroxyl group (meth)acrylate monomer.

[0025] 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.

[0026] The above-mentioned active energy ray curable compounds may be used individually or in combination of two or more. Furthermore, the above-mentioned active energy ray curable compounds may be monomers or partially polymerized oligomers in the anti-glare layer forming composition.

[0027] The filler is primarily a material that forms fine irregularities on the surface of the anti-glare layer 2, thereby providing a function to diffuse ambient light, and is not particularly limited as long as it contains inorganic fine particles. Other fillers that can be used include known organic fine particles.

[0028] In addition to exhibiting the functions described above, inorganic nanoparticles, when used in combination with organic nanoparticles, can increase the viscosity of the composition, thereby adjusting the sedimentation and aggregation of organic nanoparticles and appropriately controlling the formation of surface irregularities. Examples of inorganic nanoparticles include inorganic silica nanoparticles. Metal oxide nanoparticles and various mineral nanoparticles can also be used. Examples of inorganic silica nanoparticles include colloidal silica and silica nanoparticles surface-modified with reactive functional groups such as (meth)acryloyl groups. Pre-mixed inorganic silica nanoparticles with the active energy ray curable compound can also be used. Examples of metal oxide nanoparticles include alumina, zinc oxide, tin oxide, antimony oxide, indium oxide, titania, and zirconia. Examples of mineral nanoparticles include mica, synthetic mica, vermiculite, montmorillonite, iron montmorillonite, bentonite, beidelite, saponite, hectorite, stevensite, nontronite, magadiite, islarite, kanemite, layered titanate, smectite, and synthetic smectite. The mineral nanoparticles may be natural products or synthetic products (including substituted products and derivatives), or mixtures of both may be used. Among the mineral nanoparticles, layered organic clay minerals are more preferred. Layered organic clay refers to a material in which organic onium ions are introduced between the layers of swellable clay. The organic onium ions are not limited as long as they can be organicated by utilizing the cation exchange properties of the swellable clay. When layered organic clay minerals are used as mineral nanoparticles, synthetic smectite can be suitably used. Synthetic smectite has the function of increasing the viscosity of the anti-glare layer forming composition, suppressing the settling of organic and inorganic nanoparticles, and adjusting the uneven surface shape of the anti-glare layer. The average particle size of the inorganic nanoparticles is preferably 10 to 200 nm, more preferably 10 nm to 50 nm. The average particle size of the inorganic silica nanoparticles is also preferably about the same as above.

[0029] As organic fine particles, for example, 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 polyfluoroethylene resin, or modified resin materials thereof, can be used. In order to adjust the refractive index and dispersion of the resin particles, two or more types of resin particles with different materials (refractive index) may be used in combination. The average particle size of the organic fine particles is preferably 0.5 μm or more, more preferably 1.5 μm or more, even more preferably 2.0 μm or more, even more preferably 3 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 6 μm or less.

[0030] From the viewpoint of achieving both low haze and high anti-glare properties, the refractive index of the filler is preferably smaller than the refractive index of the cured active energy ray curable compound (or, in the case of using multiple active energy ray curable compounds, the refractive index of the cured mixture). Furthermore, even if it is larger than the refractive index of the cured active energy ray curable compound, it is preferable if the difference is within a range of about 0.01, as this does not easily lead to high haze. When multiple fillers are used, it is preferable that all fillers satisfy the above relationship. Examples of the refractive index of the filler include approximately 1.40 to 1.60, and more preferably approximately 1.40 to 1.52. When organic fine particles have a refractive index within the above range, both internal and external haze are reduced, and high haze can be suppressed even with large surface irregularities.

[0031] The inorganic fine particles are preferably 5% by mass or more, more preferably 7% by mass or more, even more preferably 7.0% by mass or more, and preferably 80% by mass or less, and more preferably 50% by mass or less, of the total amount of solid components. In this specification, the total amount of solid components refers to the total amount of all components other than the solvent in the composition.

[0032] The content of organic fine particles is preferably 3% by mass or more, more preferably 5% by mass or more, and preferably 20% by mass or less, and more preferably 10% by mass or less, of the total amount of solid components. When multiple organic and inorganic fine particles are used, the content of each refers to the total content.

[0033] The anti-glare layer-forming composition may contain a photopolymerization initiator or a solvent, if necessary.

[0034] Examples of photopolymerization initiators used in compositions for forming anti-glare layers include 2,2-ethoxyacetophenone, 1-hydroxycyclohexylphenyl ketone, dibenzoyl, benzoin, benzoin methyl ether, benzoin ethyl ether, p-chlorobenzophenone, p-methoxybenzophenone, Michler ketone, acetophenone, and 2-chlorothioxanthone. One of these may be used alone, or two or more may be used in combination. The content of the photopolymerization initiator is not particularly limited, but is, for example, 0.01 to 20% by mass of the total amount of solid components.

[0035] Solvents used in compositions for forming an anti-glare layer include ketone solvents such as acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK); alcohol solvents such as ethanol, methanol, isopropyl alcohol (IPA), and isobutanol; ether solvents such as ethylene glycol dimethyl ether and propylene glycol monomethyl ether (PGME); ester solvents such as ethyl acetate, propylene glycol monomethyl ether acetate (PGMEA), and 2-ethoxyethyl acetate; and aromatic hydrocarbon solvents such as toluene. These may be used individually or in combination of two or more.

[0036] Furthermore, the composition for forming the anti-glare layer may contain additives such as antistatic agents, defoaming agents, leveling agents, antioxidants, ultraviolet absorbers, infrared absorbers, light stabilizers, polymerization inhibitors, and photosensitizers, as needed. Such additives can further enhance the anti-glare layer's UV absorption and antistatic properties. The amount of additives can be adjusted as appropriate according to known technologies.

[0037] The thickness of the anti-glare layer is preferably 3 to 10 μm. If it is less than 3 μm, fillers such as organic fine particles will come to the surface of the coating, creating large surface irregularities, making the surface white and resulting in an unsightly appearance. If it is more than 10 μm, the coating will curl more strongly, leading to surface defects such as cracking.

[0038] The refractive index of the anti-glare layer is typically around 1.45 to 1.55.

[0039] The low refractive index layer (second functional layer) 3 has a refractive index lower than that of the lower anti-glare layer 2 and is an optical functional layer that suppresses reflection through optical interference. Examples of refractive indices include 1.25 to 1.45.

[0040] The low refractive index layer 3 can be formed by applying a composition containing an active energy ray curable compound (also called the "low refractive index layer forming composition") to the surface of the anti-glare layer 2 and curing the coating film. The low refractive index layer 3 may also contain a refractive index adjusting agent for refractive index adjustment.

[0041] As refractive index adjusting agents, fine particles such as LiF, MgF, 3NaF·AlF or AlF (all with a refractive index of 1.4), or Na3AlF6 (crylcite, refractive index 1.33), or silica fine particles with internal voids can be suitably used. Silica fine particles with internal voids are advantageous for lowering the refractive index of the low refractive index layer because the void portion can have the refractive index of air (approximately 1). Specifically, porous silica particles and silica particles with a shell structure can be used. The content of the refractive index adjusting agent is not particularly limited, and is, for example, 0.01 to 70% by mass of the total amount of solid components. Note that the refractive index adjusting agent is 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 anti-glare layer 2, the refractive index adjusting agent may be omitted.

[0042] As the active energy ray curable compound, the polymerizable compound described in the section on the anti-glare layer can be used. In addition, the photopolymerization initiator and solvent described above may be added to the low refractive index layer forming composition as appropriate.

[0043] Since the low refractive index layer 3 is the outermost functional layer, the composition for forming the low refractive index layer may contain antifouling agents, leveling agents, oil repellents, water repellents, and fingerprint inhibitors as components to improve antifouling properties. Fluorine-containing compounds and silicone compounds can be suitably used as these additives. In the present invention, when the above-mentioned antifouling-improving components are used, the fingerprint-wiping properties can be further improved due to the synergistic effect of the surface irregularities. The content of the antifouling-improving components is not particularly limited, and is, for example, 0.01 to 20% by mass of the total amount of solid components.

[0044] The composition for forming a low refractive index layer may optionally contain other additives such as antistatic agents, defoamers, antioxidants, ultraviolet absorbers, infrared absorbers, colorants, light stabilizers, polymerization inhibitors, and photosensitizers. The content of these additives can be adjusted as appropriate according to known technology.

[0045] The thickness of the low refractive index layer is not particularly limited, but due to its properties as an optical interference layer, it is preferably in the range of 5 nm to 1 μm, and more preferably 50 to 400 nm. It is more preferable in terms of thinning and suppressing reflectivity to design the optical film thickness (nd), obtained by multiplying the film thickness of the low refractive index layer 3 by the refractive index of the low refractive index layer 3, to be approximately equal to 1 / 4 of the wavelength of visible light (the wavelength to be suppressed).

[0046] 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 shielding layer, an infrared absorption layer, an ultraviolet absorption layer, or a color correction layer, may be laminated between the transparent substrate 1 and the anti-glare layer 2, and between the anti-glare layer 2 and the low refractive index layer 3.

[0047] The coating method for each of the above-mentioned layer compositions is not particularly limited, and can be used, for example, with a spin coater, roll coater, reverse roll coater, gravure coater, microgravure coater, knife coater, bar coater, wire bar coater, die coater, dip coater, spray coater, applicator, etc.

[0048] The coated composition can be photocured by heating and drying, followed by irradiation with ultraviolet light using a known light source such as a halogen lamp.

[0049] Thus, the optical laminate of the present invention is obtained. The thickness of the optical laminate of the present invention is not particularly limited and may be, for example, 20 to 120 μm.

[0050] The surface irregularities of the optical laminate of the present invention will be described in detail. The irregularities on the outermost surface of the optical laminate satisfy the following conditions (1) and (2). 6,000 ≤ A ≤ 40,000 (1) 50 ≤ B ≤ 800 (2) Here, A and B are values ​​derived from spatial frequencies f calculated from a predetermined range of the transformed image (power spectrum image) after performing a Fast Fourier Transform (FFT) on image data generated from measurement data of the surface unevenness of the optical laminate. A is the average value of the power spectrum intensity in the range of 50 cycles / mm ≤ f ≤ 100 cycles / mm (also called "power spectrum intensity A"), and B is the average value of the power spectrum intensity in the range of 200 cycles / mm ≤ f ≤ 250 cycles / mm (also called "power spectrum intensity B").

[0051] The calculation methods for the values ​​of A and B above are as follows:

[0052] First, we will explain the properties of the optical laminate obtained by analyzing its surface shape using a two-dimensional Fourier transform. The surface shape analysis is performed using the following procedure.

[0053] (i) Three-dimensional data is acquired regarding the surface shape of the optical laminate. The three-dimensional data includes height information of the surface irregularities at each position on the surface of the optical laminate. The three-dimensional data is obtained by measuring the surface shape of the optical laminate using an optical interferometer or a contact-type measuring device. Typical examples of optical interferometer measuring devices are white light interferometers and laser microscopes, while typical examples of contact-type measuring devices are surface roughness meters and scanning probe microscopes. The acquired three-dimensional data is converted into an image (first image) in which the surface irregularity height information is used as pixel values.

[0054] (ii) Using the image obtained by transforming the above three-dimensional data (first image), a Fast Fourier Transform (FFT) is performed to obtain the image after FFT processing (second image). That is, the wave consisting of the change in height on the surface of the optical laminate is decomposed into spatial frequency components.

[0055] More specifically, a grayscale image is generated from the above three-dimensional data, representing the height information as brightness and darkness in predetermined gradations. Specifically, a grayscale image is generated by converting the height information to 256 levels of brightness and darkness, such that the minimum value is 0 and the maximum value is 255. Then, a two-dimensional Fourier transform is performed on the grayscale image. The power spectrum intensity obtained can be restored to a value corresponding to the height by performing the inverse transformation of the conversion from height information to brightness and darkness. This yields data obtained by applying a Fast Fourier Transform to the height information of the irregularities at each position on the surface of the optical laminate.

[0056] Alternatively, a two-dimensional Fourier transform may be performed using the height information itself as the processing target, without going through a conversion to brightness.

[0057] The number of pixels in the three-dimensional data and grayscale image, and the number of pixels in the power spectrum FFT image, are not particularly limited. For example, when performing a two-dimensional Fourier transform on a 640px × 480px image to generate a 1024px × 1024px FFT image, the height data of the 480 columns is decomposed into 1024 frequencies for each row, then transposed vertically and horizontally, and the height data of the 640 columns is decomposed into 1024 frequencies for each row. This results in a 1024px × 1024px FFT image.

[0058] (iii) For the power spectrum obtained by the Fast Fourier Transform described above, one arbitrary direction passing through the origin, which is the point where the spatial frequency is 0, is set as the target direction, and the power spectrum intensity is output for each spatial frequency in the target direction. The power spectrum intensity is obtained by logarithmically transforming it using the common logarithm. The surface irregularities of the optical laminate are irregular, and no periodicity in any particular direction is observed in the power spectrum. Therefore, the distribution of intensity in the power spectrum will be the same regardless of which direction is set as the target direction. In addition, to remove noise, the average of the power spectrum intensities near the target spatial frequency may be used as the power spectrum intensity for that spatial frequency.

[0059] For example, in the image showing the power spectrum (second image) described above, the x-axis is set horizontally through the origin, and the target region is defined as x > 0 and ±20 pixels vertically from the x-axis. Then, the power spectrum intensity is averaged for each x-coordinate within the target region and taken as the power spectrum intensity for the spatial frequency corresponding to each x-coordinate.

[0060] Figure 2 shows a typical example of the power spectrum in the target direction obtained by analyzing the surface shape of the optical laminate of this embodiment. At each spatial frequency, a larger power spectrum intensity indicates a larger height of the irregularities located at the period corresponding to that spatial frequency.

[0061] In the example shown in Figure 2, the power spectrum intensity decreases as the spatial frequency increases, and no prominent peaks are observed at specific spatial frequencies. Therefore, it can be said that the height of the irregularities tends to decrease as the period of the irregularities decreases. This tendency is due to the fact that irregularities with large periods are located in areas where particles are aggregated, and the height of these irregularities increases because the particles are concentrated there. Furthermore, as mentioned above, since there are areas where particles are aggregated, areas where particles are scattered individually, and areas where no particles are present, a power spectrum is obtained in which the intensity decreases as the spatial frequency increases.

[0062] From the obtained spatial frequencies, the average values ​​of the true power spectrum intensity in the ranges of 50 cycles / mm ≤ f ≤ 100 cycles / mm and 200 cycles / mm ≤ f ≤ 250 cycles / mm are calculated and used as the values ​​A and B above.

[0063] Conventionally, to achieve fingerprint-wiping properties, antifouling components such as fluorine compounds and silicone compounds are included in the outermost layer. However, there are limitations to improving fingerprint wiping properties by adding antifouling components alone. Through previous studies by the inventors, it has been found that not only the material and components of the outermost layer, but also the surface irregularity shape, affects fingerprint wiping properties. In the present invention, the surface irregularity shape that improves fingerprint wiping properties can be evaluated based on the power spectrum intensity of the spatial frequency, calculated from data obtained by FFT transformation of three-dimensional data of the surface irregularity height. Around a spatial frequency of 50 cycles / mm, the surface irregularity shape is characterized by a waveform with a period of 20 μm and is formed by aggregates of fillers, etc. Therefore, the higher the power spectrum intensity in that vicinity (i.e., the higher the irregularity height), the better the fingerprint wiping properties. On the other hand, in the present invention, from the viewpoint of exhibiting anti-glare and low-haze properties in addition to fingerprint resistance, it is preferable that the power spectrum intensity is not too high. Therefore, in the present invention, it is preferable that the power spectrum intensity A in the spatial frequency range of 50 cycles / mm ≤ f ≤ 100 cycles / mm satisfies 6,000 ≤ A ≤ 40,000. Furthermore, from the power spectrum around a spatial frequency of 200 cycles / mm, it can be seen that the surface irregularity shape is the shape of surface irregularities formed by individual fillers with a waveform size of 5 μm period. From the viewpoint of achieving both anti-fingerprint and anti-glare properties, in the present invention, it is preferable that the power spectrum intensity B in the spatial frequency range of 200 cycles / mm ≤ f ≤ 250 cycles / mm satisfies 50 ≤ B ≤ 800. When the power spectrum intensity A and power spectrum intensity B are within the range, the surface irregularity shape is moderately large, so that the appearance does not become white, moderate anti-glare properties are obtained, and the haze does not become high, while suppressing a decrease in fingerprint wiping ability.

[0064] The optical laminate of the present invention has excellent fingerprint-wiping properties if the surface irregularities satisfy the above conditions (1) and (2). If either value A or B falls outside the range of conditions (1) and (2), the fingerprint-wiping properties deteriorate, or optical properties deteriorate, such as increased haze due to stronger surface scattering or a whitish appearance. The values ​​of A and B can be controlled by adjusting the particle size and amount of filler added to the anti-glare layer 2, the amount of additive, the film thickness of the anti-glare layer 2, and the aggregation state of the filler during the film formation process.

[0065] In the optical laminate of the present invention, an artificial leather coated with olive oil is pressed onto the surface of the optical laminate (low refractive index layer), and then wiped with tissue paper under a load of 1 kg. After each wipe, the reflection spectrum of the olive oil-coated area is measured, and the fingerprint-wiping ability is evaluated by the color difference ΔE*ab value before and after coating. ΔE*ab is calculated according to the following formula. ΔE*ab={(ΔL*) 2 +(Δa*) 2 +(Δb*) 2} 1 / 2 When the ΔE*ab value is 0.5 or less, it can be determined that the fingerprint wiping performance is good. In this specification, the number of times fingerprint wiping is required to achieve a ΔE*ab value of 0.5 or less is measured, and if the number is 12 or less, it is evaluated as having excellent fingerprint wiping performance. The number of times fingerprint wiping is preferably 12 or less, and more preferably 9 or less.

[0066] The optical laminate of the present invention preferably has a 0° reflectance of 0.25% or less, measured using a display glare measuring instrument (DM&S, SMS-1000) in a reflectance and anti-glare measurement mode compliant with ASTM E430 and ASTM D5767. Here, the 0° reflectance is a value measured and calculated as follows, and will be explained using the schematic diagram in Figure 3 which shows an example of a glare measuring instrument.

[0067] First, a blackboard (calibration board) with a known reflectivity is placed on the stage of the glare measuring instrument, and the instrument is calibrated. The reflectivity of the calibration board is not particularly limited; for example, a calibration board with a reflectivity of 4.22% can be used.

[0068] Next, the sample to be measured is placed on the stage of the glare measuring instrument, and light from a CCFL light source is shone through a 1 mm wide x 100 mm long slit from a position 300 mm above the sample. The image of the CCFL light source projected onto the sample is captured by a camera installed in the measuring instrument. The camera is positioned directly above the image of the CCFL light source projected onto the sample, and the optical axis of the camera coincides with the center of the CCFL light source image in the width direction. Here, the intersection of the optical axis of the camera and the surface of the sample to be measured is defined as point O, and the intensity of the light at point O is measured (also called 0° reflectance or reference intensity).

[0069] In this specification, 0° reflectance indicates the brightness of the reflected image (CCFL image) obtained through the optical laminate, and therefore primarily serves as an indicator of low reflectivity. A higher value indicates a highly reflective and clear optical laminate, while a lower value indicates a less reflective and blurred optical laminate. In this specification, a 0° reflectance of 0.25% or less indicates excellent anti-glare properties, and a smaller value indicates even better anti-glare properties.

[0070] Furthermore, the optical laminate of the present invention can be evaluated for its anti-glare properties by calculating the reflective haze as the reflectance value at each angle relative to the 0° reflectance measured in reflective protection measurement mode using a display glare measuring instrument (DM&S, SMS-1000). Here, the reflective haze is a value measured and calculated as follows, and will be explained using the schematic diagram in Figure 3 which shows an example of a glare measuring instrument.

[0071] On the captured image of the measurement sample described above, the light intensity is measured at multiple points P on a straight line that passes through point O, which corresponds to the optical axis of the camera, and is perpendicular to the longitudinal direction of the CCFL light image (the direction corresponding to the length of the slit). Specifically, when the camera's focal point is F, the reflected intensity is calculated at multiple points P where the angle OFP (=θ) between the camera's optical axis (the straight line passing through points F and O) and the straight line passing through points F and P is 1°, 1°±0.2°, -1°, and -1°±0.2°. In addition, the reflected intensity at multiple points P where the angle OFP is 2°, 2°±0.2°, -2°, and -2°±0.2°, and the reflected intensity at multiple points P where the angle OFP is 5°, 5°±0.2°, -5°, and -5°±0.2° are calculated. The average of the reflectance intensities at the positions of 1°, 1°±0.2°, -1°, and -1°±0.2° of the measurement sample is divided by the reflectance intensity at 0° to obtain the θ1° reflectance haze. The average of the reflectance intensities at the positions of 2°, 2°±0.2°, -2°, and -2°±0.2° of the measurement sample is divided by the reflectance intensity at 0° to obtain the θ2° reflectance haze. The average of the reflectance intensities at the positions of 5°, 5°±0.2°, -5°, and -5°±0.2° of the measurement sample is divided by the reflectance intensity at 0° to obtain the θ5° reflectance haze.

[0072] In this specification, the reflective haze at θ1° is an indicator of low reflectivity, brightness of the fluorescent lamp image (low haze), and brightness of the reflected scenery, and is preferably 20-90%. The reflective haze at θ2° is an indicator of the blurring of the outline of the fluorescent lamp image and the blurring of the reflected scenery, and is preferably 10-80%. The reflective haze at θ5° is an indicator of peripheral intensity, such as whiteness, blackness, and light diffusion, and is preferably 1-50%. In this specification, it is indicated that the anti-glare properties are excellent when the reflective haze is within the above ranges.

[0073] The haze value (total haze value, according to JIS K7136) of the optical laminate of the present invention is not particularly limited, but is preferably 3 to 20%. A haze value of 3% or more is preferable because it exhibits an anti-glare effect. Furthermore, a haze value of 20% or less is preferable because it suppresses whitening of the appearance.

[0074] The transmitted image clarity of the optical laminate of the present invention can be measured in accordance with JIS K7105 using an image measuring instrument (Suga Test Instruments, ICM-1T). The transmitted image clarity is not particularly limited, but is preferably 40% or more, more preferably 45% or more, and preferably 85% or less, more preferably 80% or less. When the transmitted image clarity is 40% or more, whitening of the appearance is suppressed, which is preferable. Furthermore, when the transmitted image clarity is 85% or less, the anti-glare properties are good, which is preferable.

[0075] The optical laminate of the present invention can be used to construct an image display device by laminating it 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 optical laminate and the image display panel. Because the optical laminate of the present invention has excellent fingerprint-wiping properties, it is suitable as an optical film to be provided on the outermost surface of an image display device equipped with a touch panel. [Examples]

[0076] The present invention will be specifically described below with reference to examples, but the present invention is not limited in any way by these examples.

[0077] The ingredients used are listed below. <Transparent base material> • Triacetylcellulose (TAC) film: 60 μm thick <First functional layer forming composition> • Polyfunctional acrylic resin a (dipentaerythritol hexaacrylate, resin refractive index 1.52) • Polyfunctional acrylic resin b (prepared according to the manufacturing method described below, hydroxyl value 86 mg KOH / g, weight-average molecular weight 55,000, resin refractive index 1.52) • Inorganic silica-containing resin (Momentive Performance Materials, UVHC7800G, SiO2 83%, resin refractive index 1.50) • Colloidal silica (manufactured by Nissan Chemical, MIBK-AC-2140Z, SiO2 40%, average particle size 12nm) ·Organic fine particles a (Sekisui Plastics, SSX-103, average particle size 3μm, refractive index 1.50) ·Organic fine particles b (Sekisui Plastics, SSX-105, average particle size 5μm, refractive index 1.50) • Organic microparticles c (manufactured by Fuji Silysia Chemical, SYLOPHOBIC 100, average particle size 2.7 μm, refractive index 1.46) • Organic microparticles d (manufactured by Fuji Silysia Chemical, SYLOPHOBIC 200, average particle size 3.9 μm, refractive index 1.46) • Organic microparticles e (manufactured by Fuji Silysia Chemical, SYLOPHOBIC 702, average particle size 4.1 μm, refractive index 1.46) ·Organic fine particles f (Soken Chemical, SX-350H, average particle size 3.5μm, refractive index 1.59) • Organic fine particles (manufactured by Soken Chemical, SX-500H, average particle size 5.0 μm, refractive index 1.59) • Photopolymerization initiator (Omnirad184, manufactured by IGM Resins BV) • Leveling agent (DIC, F-565) <Composition for forming second functional layer> • Polyfunctional acrylic resin c (pentaerythritol triacrylate) • Inorganic microparticles (hollow silica, average particle size 75 nm) • Fluorine-based antifouling agent (manufactured by Shin-Etsu Chemical Co., Ltd., KY-1203)

[0078] Manufacturing Example 1 of Polyfunctional Acrylic Resin b 80 parts by mass of propylene glycol monomethyl ether was prepared as the polymerization solvent. Additionally, 16 parts by mass of methyl methacrylate and 4 parts by mass of 2-hydroxymethyl methacrylate were prepared as acrylic monomers. Furthermore, 0.30 parts by mass of benzoyl peroxide (BPO) was prepared as a polymerization initiator. These were placed in a reaction vessel equipped with a stirrer and a reflux tubing, and the mixture was stirred and refluxed for 8 hours while heating to 80°C, with nitrogen gas introduced into the vessel. This yielded a polymer solution of polyfunctional acrylic resin b, formed from methyl methacrylate and 2-hydroxymethyl methacrylate (hydroxyl value 86 mgKOH / g, average polymerization molecular weight 55,000).

[0079] Examples 1-18 and Comparative Examples 1-6 <Anti-glare layer (first functional layer)> The organic fine particles shown in Tables 1-4 were dispersed in propylene glycol monomethyl ether solvent using a paint shaker for 30 minutes. Using the resulting dispersion of organic fine particles, the raw materials shown in Tables 1-4 were mixed with propylene glycol monomethyl ether solvent to a total solid content of 50% by mass, and the mixture was stirred in a paint shaker for 30 minutes to prepare a composition for forming an anti-glare layer.

[0080] Next, a 60 μm thick triacetylcellulose film (TAC film, manufactured by Fujifilm, TG60) was used as a transparent support. The anti-glare layer-forming composition was applied to one surface of the transparent support using a bar coater, dried in a dryer at 100°C for 1 minute, and then exposed to a high-pressure mercury UV device under a nitrogen atmosphere (oxygen concentration of 500 ppm or less) with an integrated exposure dose of 300 mJ / cm². 2 The first functional layer (anti-glare layer), which was laminated and cured to a thickness of 6 μm after curing, was formed by UV irradiation in such a manner.

[0081] <Low refractive index layer (second functional layer)> A composition for forming a low refractive index layer was prepared by mixing 45.0 parts by mass of PETA (pentaerythritol triacrylate), 50.0 parts by mass of isopropyl alcohol-dispersed hollow silica fine particles with an average particle size of 75 nm, 3.0 parts by mass of a UV-curable photopolymerization initiator, and 2.0 parts by mass of a fluorine-based antifouling agent (Shin-Etsu Chemical Co., Ltd., KY-1203) with isopropyl alcohol solvent to a total solid content of 3.5% by mass, and stirring in a paint shaker for 30 minutes.

[0082] The obtained low refractive index layer-forming composition was applied to the surface of the first functional layer using a bar coater, dried in a dryer at 100°C for 1 minute, and exposed to a nitrogen atmosphere (oxygen concentration of 500 ppm or less) using a high-pressure mercury UV device with an integrated exposure dose of 300 mJ / cm². 2The second functional layer (low refractive index layer) was formed by curing a laminated material after UV irradiation to achieve the desired optical film thickness (nd = refractive index n × film thickness d (nm)) of nd = 550 / 4nm, with the concentration adjusted as appropriate. The refractive index of the low refractive index layer was approximately 1.32.

[0083] Furthermore, the refractive index of the resin components constituting each layer was measured by the following method. The resin components shown in Tables 1 to 4 were mixed and coated onto a silicon wafer substrate using a spin coater to obtain a film thickness of 0.3 μm after drying at 60°C, thereby obtaining coatings of only each resin component. The refractive index at 589 nm (D line) was measured using an ellipsometer (VUV-VASE, manufactured by J.A. Woolam Japan).

[0084] Test Example 1 [Surface Irregularities] (Acquisition of 3D data) Using Vertscan (R3300H Lite, manufactured by Ryoka Systems), three-dimensional data of the surface topography of the optical laminate was measured using optical interferometry. The measurement conditions were as follows: The topography height was based on the lowest point within the measurement range. Camera model: Sony HR-50 1 / 3 • Objective lens magnification: 5XTI • Telescope tube: 1X • Zoom lens: 1X ·Light source: 530white • Wavelength filter: 520nm • Measurement device: Piezo • Measurement mode: Phase • Scan speed: 4 μm / sec • Scan range: 10μm to -10μm Effective pixels: 0% • Measurement range: 940.8 μm × 705.6 μm, 640 pixels × 480 pixels ·XY direction resolution: 1pixel 1.47μm

[0085] (FFT analysis) Next, FFT analysis was performed on the obtained three-dimensional data using the free software "ImageJ 1.53h" in a Windows® 10 environment. The procedure is as follows: 1. The three-dimensional data was converted into TIFF image data, where height is represented by pixel values. 2. An FFT was performed using the original 3D data values ​​(height measurements). The image size after FFT processing was 1024 pixels × 1024 pixels. 3. After FFT processing, the power spectrum intensity was restored to the measured value in the image. 4. The power spectrum intensity was output for a range of ±20 pixels on the positive x-axis passing through the origin in the processed image. 5. The x-coordinate of the output power spectrum was converted to a spatial frequency f based on the pixel size of the original three-dimensional data. 6. From the calculated spatial frequencies, the average values ​​(values ​​A and B) of the power spectrum intensity in the ranges of 50 cycles / mm ≤ f ≤ 100 cycles / mm and 200 cycles / mm ≤ f ≤ 250 cycles / mm were calculated.

[0086] The FFT of the three-dimensional data described above is a process for decomposing a wave consisting of changes in the surface height of an optical film into its spatial frequency components.

[0087] In step 1 above, a grayscale image may be generated from the three-dimensional data in which the height information is represented as brightness and darkness of a predetermined range. Specifically, a grayscale image can be generated by converting the height information into numerical values ​​representing brightness and darkness of 256 levels, where the minimum value is 0 and the maximum value is 255. In this case, in step 2 above, a two-dimensional Fourier transform is performed on the obtained grayscale image. By performing the inverse transformation of the conversion from height information to brightness and darkness on the power spectrum intensity obtained by the two-dimensional Fourier transform, the power spectrum intensity is restored to a value corresponding to the height. This provides data obtained by applying the Fast Fourier Transform to the height information of the irregularities at each position on the surface of the optical film 10.

[0088] Alternatively, in step 1 above, the conversion to a value representing brightness may be omitted, and in step 2 above, the height information itself may be used as the processing target and a two-dimensional Fourier transform may be performed.

[0089] Furthermore, the number of data points in the three-dimensional data, the number of pixels in the grayscale image, and the number of pixels in the power spectrum FFT image are not particularly limited. For example, when performing a two-dimensional Fourier transform on a 640 pixels × 480 pixels image to generate a 1024 pixel × 1024 pixel FFT image, the height data of 480 rows is decomposed into 1024 frequencies for each row, then transposed vertically and horizontally, and the height data of 640 columns is decomposed into 1024 frequencies for each column. This results in a 1024 pixel × 1024 pixel FFT image.

[0090] The specific procedure for performing FFT analysis using the image analysis software "ImageJ 1.53h" is shown below. (1) The three-dimensional data was imported into the image analysis software as TIFF image data. (2) In the image analysis software mentioned above, select "FFT Options" and check "Raw power spectrum". Then, perform the Fast Fourier Transform process. This will open an image named "FFT of (filename)" and an image named "PS of (filename)". Each image is 1024 pixels x 1024 pixels in size. The "FFT of (filename)" image shows the power spectrum intensity normalized to 256 levels of brightness and darkness, while the "PS of (filename)" image shows the power spectrum intensity as a value corresponding to the height of the three-dimensional data. (3) The "FFT of (filename)" image was closed, and the command "Log" and "Macro..." with "code:v=v / 2.303;" were executed on the "PS of (filename)" image. This caused the z axis, which represents the power spectrum intensity, and each value to be logarithmically transformed using the common logarithm. (4) For the image after the process in (3) above, with the center of the image as the origin, the x-axis was set in the horizontal direction passing through the origin, and a range of ±20 pixels in the vertical direction from the x-axis was specified, and the power spectrum intensity of each pixel was output. Then, the average value of the power spectrum intensity was calculated for pixels with the same x-coordinate, and this was used as the power spectrum intensity for each x-coordinate. (5) The x-coordinates of the output power spectrum intensity were converted to spatial frequencies with 1 millimeter as the unit length based on the pixel size of the three-dimensional data. (6) From the power spectrum intensity of each spatial frequency, the intensity integral values A and B were calculated respectively.

[0091] Test Example 2 [Fingerprint Resistance] The optical laminate was adhered to a blackboard (manufactured by Sumitomo Chemical, Sumika Acrylic Sheet, Sumipex (registered trademark) #960 black) with an optical adhesive (manufactured by Kawaguchi Corporation, TD06) such that the functional surface was on the surface, and artificial leather with olive oil reagent adhered was pressed onto the functional surface to adhere olive oil. The adhered olive oil was repeatedly wiped off with a tissue paper (Scotty, manufactured by Nippon Paper Crecia) with a load of 1 kg. Each time it was wiped off, the color coordinates L*, a*, and b* of the reflection spectroscopy at the olive oil adhesion site were measured using a spectrophotometer (manufactured by Konica Minolta, CM-2500d). The color difference ΔE*ab before and after the olive oil adhesion was calculated according to the following formula, and the number of wiping times when the color difference ΔE*ab became 0.5 or less was evaluated and judged according to the following criteria. ΔE*ab = {(ΔL*) 2 +(Δa*) 2 +(Δb*) 2} 1 / 2 (Judgment Criteria) Very Good 5: Number of wiping times ≤ 9 times Fairly Good 4: 9 times < Number of wiping times ≤ 12 times Good 3: 12 times < Number of wiping times ≤ 15 times Not So Good 2: 15 times < Number of wiping times ≤ 20 times Bad 1: 20 times < Number of wiping times [[ID=​​ The measurement sample was a 10cm x 10cm x 2mm blackboard (Sumitomo Chemical, Sumika Acrylic Sheet, Sumipex #960 Black) to which an optical laminate was attached using an optical adhesive (Tomoegawa Corporation, TD06) with the functional surface facing outwards.

[0093] First, a calibration plate with a known reflectivity (4.22%) was placed on the stage of a display glare meter (DM&S, SMS-1000), and the meter was calibrated.

[0094] Next, the sample to be measured was placed on the stage, and light from a CCFL light source was shone through a 1 mm wide x 100 mm long slit from a position 300 mm above the sample. The image of the CCFL light source projected onto the sample was captured by a camera mounted on the measuring instrument. The camera was positioned directly above the image of the CCFL light source projected onto the sample, and the camera's optical axis coincided with the center of the CCFL light source image in the width direction. Here, the intersection of the camera's optical axis and the surface of the sample to be measured was defined as point O, and the intensity of the light at point O was measured (reference intensity).

[0095] Next, on the captured image of the measurement sample, the light intensity at multiple positions on point P, which is on a straight line passing through point O (corresponding to the optical axis of the camera) and perpendicular to the longitudinal direction of the CCFL light image (corresponding to the length direction of the slit), was measured. Specifically, with the camera's focal point at F, the reflected intensity at multiple points P where the angle OFP (=θ) between the camera's optical axis (the straight line passing through points F and O) and the straight line passing through points F and P is 1°, 1°±0.2°, -1°, and -1°±0.2° was calculated. In addition, the reflected intensity at multiple points P where the angle OFP is 2°, 2°±0.2°, -2°, and -2°±0.2° was calculated, and the reflected intensity at multiple points P where the angle OFP is 5°, 5°±0.2°, -5°, and -5°±0.2° was calculated. Then, the average of the reflectance intensities at the positions of 1°, 1°±0.2°, -1°, and -1°±0.2° of the measurement sample was divided by the reflectance intensity at 0° (reference intensity) of the measurement sample to obtain the reflective haze at θ1°. The average of the reflectance intensities at the positions of 2°, 2°±0.2°, -2°, and -2°±0.2° of the measurement sample was divided by the reflectance intensity at 0° of the measurement sample to obtain the reflective haze at θ2°. The average of the reflectance intensities at the positions of 5°, 5°±0.2°, -5°, and -5°±0.2° of the measurement sample was divided by the reflectance intensity at 0° of the measurement sample to obtain the reflective haze at θ5°.

[0096] The obtained 0° reflectance, θ1° reflectance haze, θ2° reflectance haze, and θ5° reflectance haze were evaluated according to the following criteria. (Judgment criteria) 0°reflectance: 0.25% or less Reflection haze at θ1°: 20% or more, 90% or less Reflection haze at θ2°: 10% or more, 80% or less Reflection haze at θ5°: 1% or more, 50% or less

[0097] Test Example 4 [Hayes] Haze was measured using a haze meter (NDH7000, manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with the haze test method specified in JIS K7136, a standard for testing the optical properties of plastics. A haze value of 3-20% was considered good, and a lower value indicated suppressed light diffusion by the optical laminate.

[0098] Test Example 5 [Transmission Image Clarity] The clarity of the transmitted image was measured using an image measuring instrument (Suga Test Instruments, ICM-1T) in accordance with JIS K7105, using a 0.5 mm wide optical comb. A transmission image clarity of 40% to 85% was considered good, and any other result was considered poor.

[0099] Tables 1-4 show the evaluation results.

[0100] [Table 1]

[0101] [Table 2]

[0102] [Table 3]

[0103] [Table 4]

[0104] Tables 1-4 show that, in comparison with Comparative Examples 1-6, Examples 1-18 achieve both anti-fingerprint and anti-glare properties. In particular, Examples 1-15 achieve both anti-fingerprint and anti-glare properties, as well as low haze. On the other hand, Comparative Examples 1-5 have power spectrum intensity A and power spectrum intensity B values ​​that do not fall within the specified range, and are inferior in anti-glare properties. Comparative Example 6 has a low inorganic silica content, and the surface unevenness is not sufficiently formed, resulting in inferiority in both anti-fingerprint and anti-glare properties. [Industrial applicability]

[0105] The optical laminate of the present invention is suitably used as an optical film provided on the outermost surface of an image display device. [Explanation of Symbols]

[0106] 1 Transparent base material 2 First functional layer (anti-glare layer) 3. Second functional layer (low refractive index layer) 10 Optical laminate

Claims

1. An optical laminate comprising a transparent substrate, a first functional layer having an inorganic fine particle content of 5 to 80% by mass, and a second functional layer having a refractive index lower than that of the first functional layer, laminated in this order, and having an uneven surface, characterized in that it satisfies the following conditions (1) and (2). 6,000 ≤ A ≤ 40,000 (1) 50 ≤ B ≤ 800 (2) (Here, the three-dimensional data of the unevenness height measured by the optical interferometry method or contact method is converted into a first image data in which the unevenness height is the pixel value, the first image data is converted into a second image by the Fast Fourier Transform, and the spatial frequency f of the X coordinate of the power spectrum of the second image that passes through the origin and is in the range of ±20 pixels on the positive X axis is calculated, A: Average value of power spectrum intensity in the range of 50 cycles / mm ≤ f ≤ 100 cycles / mm. B: Average value of power spectrum intensity in the range of 200 cycles / mm ≤ f ≤ 250 cycles / mm (is)

2. The optical laminate according to claim 1, characterized in that the 0° reflectance measured using a display glare meter (SMS-1000, manufactured by DM&S) is 0.25% or less.

3. The optical laminate according to claim 1, characterized in that, in reflection and anti-glare measurement, the reflection haze is such that the value at θ1° is 20 to 90%, the value at θ2° is 10 to 80%, and the value at θ5° is 1 to 50%.

4. The optical laminate according to claim 1, characterized in that the haze value measured in accordance with JIS K7136 is 3 to 20%.

5. The optical laminate according to claim 1, characterized in that the first functional layer contains an active energy ray curable compound, inorganic fine particles, and organic fine particles, wherein the refractive index of the organic fine particles is smaller than the refractive index of the active energy ray curable compound after curing.

6. The optical laminate according to claim 1, characterized in that the second functional layer contains an antifouling agent.

7. The optical laminate according to claim 6, characterized in that the antifouling agent contains a fluorine-containing compound or a silicone compound.

8. An image display device comprising an optical laminate according to any one of claims 1 to 7.

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