Antireflection film and image display device

Abstract

To provide an antireflection film which is excellent in adhesion between a hard coat layer and an antireflection layer and hardly causes scratches and interlayer peeling due to impact from the outside.SOLUTION: An antireflection film (100) includes a hard coat film (1) including a hard coat layer (11) on a film substrate (10), an antireflection layer (5) provided on the hard coat layer, and an antifouling layer (7) as an outermost surface layer provided on the antireflection layer. The anti-reflection layer is a stack of a plurality of thin films having different refractive indices. The hard coat layer contains a binder resin and inorganic oxide particles. The content of the inorganic oxide particles in the hard coat layer is 20 to 80% by weight. The inorganic fine particles include first type particles having a particle size of 40 to 80nm and second type particles having a particle size of 5 to 35nm, and the average primary particle size of the first type particles is in the range of 1.5 to 1.9 times the average primary particle size of the second type particles.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an antireflection film having an antireflection layer and an antifouling layer on a hard coat film, and an image display device having the antireflection film. [Background technology]

[0002] An anti-reflection film is sometimes provided on the surface of image display devices such as liquid crystal displays and organic electroluminescence displays in order to improve the visibility of displayed images. An anti-reflection film has an anti-reflection layer made up of multiple thin films with different refractive indices on a film substrate. An anti-reflection film using inorganic thin films such as inorganic oxides as the thin films that form the anti-reflection layer can easily adjust the refractive index and film thickness, thereby achieving high anti-reflection properties.

[0003] Since an antireflection film is disposed on the outermost surface of an image display device, a hard coat layer may be provided on the antireflection layer-forming surface of the film substrate for the purpose of preventing scratches due to external contact, etc. Patent Document 1 describes that the adhesion between the hard coat layer and the antireflection layer can be improved by surface-treating a hard coat layer containing fine particles to cause the fine particles to protrude from the surface of the hard coat layer, thereby increasing the surface unevenness, and then forming an antireflection layer on top of that via a primer layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-221971 Summary of the Invention [Problem to be solved by the invention]

[0005] The surface of image display devices used in notebook computers and the like is often provided with a transparent cover layer made of glass or a rigid plastic substrate for the purposes of protecting the screen from external impacts and improving the clarity of image quality. However, in recent years, configurations without a rigid cover layer have been adopted in order to reduce thickness, etc. In configurations without a cover layer, an anti-reflection film is placed on the outermost surface of the image display device, and therefore, anti-fouling properties against fingerprints and other stains are required. Furthermore, from the perspective of scratch prevention, the anti-reflection film is required to have a higher hardness.

[0006] Furthermore, image display devices for mobile use are also required to be durable against shocks such as those caused by dropping the device. For example, when a notebook computer is folded, the screen surface and the keyboard surface are in close proximity, and an external shock can cause the keyboard and screen to come into contact. Devices that do not have a cover layer on the screen surface are required to withstand such shocks without causing scratches on the anti-reflection film or peeling between layers.

[0007] By incorporating fine particles into the hard coat layer provided directly below the antireflection layer, the hardness of the antireflection film can be increased and the adhesion of the antireflection layer can be improved. However, the configuration disclosed in Patent Document 1 does not have sufficient impact resistance, and in particular, when the thickness of the hard coat layer is increased in order to increase the hardness of the antireflection film, the impact resistance tends to decrease.

[0008] In view of the above, an object of the present invention is to provide an antireflection film that has excellent adhesion between a hard coat layer and an antireflection layer and is resistant to scratches and peeling between layers due to external impact. [Means for solving the problem]

[0009] The present invention relates to an antireflection film comprising a hard coat film having a hard coat layer on one main surface of a film substrate, an antireflection layer provided on the hard coat layer, and an antifouling layer provided as a top surface layer on the antireflection layer. The antireflection layer is a laminate of multiple thin films with different refractive indices.

[0010] The hard coat layer contains a binder resin and inorganic oxide particles, and the content of the inorganic oxide particles in the hard coat layer is preferably 20 to 80 wt %.

[0011] The inorganic oxide particles of the hard coat layer include first type particles having a particle diameter of 40 to 80 nm and second type particles having a particle diameter of 5 to 35 nm. The amount of first type particles relative to the total amount of first type particles and second type particles is preferably 5 to 80 wt %. The average primary particle diameter of the first type particles is preferably within a range of 1.5 to 1.9 times the average primary particle diameter of the second type particles.

[0012] In the hard coat layer, the area ratio of inorganic oxide particles is preferably 45% or more in a cross section within a depth range of 200 to 600 nm from the surface on the antireflection layer side.The arithmetic mean height Sa of the antifouling layer is preferably 2.6 nm or more.

[0013] The indentation modulus of the surface of the antifouling layer side of the antireflection film is preferably 10 GPa or more, and the haze of the antireflection film is preferably 1.5% or less. [Effects of the Invention]

[0014] The antireflection film of the present invention has excellent interlayer adhesion because the surface of the hard coat layer is formed with irregularities due to inorganic oxide particles, and further has high impact resistance, making it less susceptible to scratches or peeling due to impacts such as dropping the device, etc. Therefore, the antireflection film of the present invention can be suitably used in image display devices that do not have a rigid cover layer on the surface. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a cross-sectional view showing a lamination configuration of an antireflection film according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] 1 is a cross-sectional view showing an example of the laminated structure of an antireflection film. The antireflection film 100 includes a hard coat film 1 having a hard coat layer 11 provided on one main surface of a film substrate 10, and an antireflection layer 5 and an antifouling layer 7 provided on the hard coat layer 11 of the hard coat film 1.

[0017] The antireflection layer 5 is a laminate of two or more inorganic thin layers with different refractive indices. In the antireflection film 100 shown in FIG. 1, the antireflection layer 5 has a configuration in which high refractive index layers 31, 33 and low refractive index layers 32, 34 are alternately laminated. The antireflection layer 5 may have a primer layer 30 on the surface that contacts the hard coat layer 11 of the hard coat film 1. The antifouling layer 7 provided on the antireflection layer 5 is the outermost layer of the antireflection film 100.

[0018] [Hard coat film] <Film substrate> A transparent film is preferably used as the film substrate 10 of the hard coat film 1. The visible light transmittance of the transparent film is preferably 80% or more, more preferably 90% or more. The resin material constituting the transparent film is preferably a resin material excellent in transparency, mechanical strength, and thermal stability. Specific examples of resin materials include cellulose-based resins such as triacetyl cellulose, polyester-based resins, polyethersulfone-based resins, polysulfone-based resins, polycarbonate-based resins, polyamide-based resins, polyimide-based resins, polyolefin-based resins, (meth)acrylic resins, cyclic polyolefin-based resins (norbornene-based resins), polyarylate-based resins, polystyrene-based resins, polyvinyl alcohol-based resins, and mixtures thereof.

[0019] The thickness of the film substrate 10 is not particularly limited, but from the viewpoints of strength, workability such as handleability, thin layer properties, etc., it is preferably about 5 to 300 μm, more preferably 10 to 250 μm, and even more preferably 20 to 200 μm. A laminate of multiple films may be used as the film substrate 10. For example, a polarizing plate in which a protective film is provided on the surface of a polarizer may be used as the film substrate 10.

[0020] <Hard coat layer> A hard coat film 1 is formed by providing a hard coat layer 11 on the main surface of a film substrate 10. The hard coat layer contains a binder resin and inorganic oxide particles. For example, a hard coat composition containing a binder resin component (a curable resin component for forming the binder resin) and inorganic oxide particles is applied to the film substrate, and the binder resin component is cured to form the hard coat layer.

[0021] (binder resin) Curable resins such as thermosetting resins, photocurable resins, and electron beam curable resins are preferably used as the binder resin for the hard coat layer 11. Examples of curable resins include polyester-based, acrylic-based, urethane-based, acrylic urethane-based, amide-based, silicone-based, silicate-based, epoxy-based, melamine-based, oxetane-based, and acrylic urethane-based resins. Among these, acrylic resins and epoxy resins are preferred because of their high hardness and photocurability, and acrylic resins are particularly preferred.

[0022] The photocurable binder resin component contains a polyfunctional compound having two or more photopolymerizable (preferably ultraviolet-polymerizable) functional groups. The polyfunctional compound may be a monomer or an oligomer. The acrylic hard coat material contains a compound (polyfunctional (meth)acrylate) containing two or more (meth)acryloyl groups in one molecule. In this specification, "(meth)acrylic" means acrylic and / or methacrylic.

[0023] Specific examples of polyfunctional compounds having two or more (meth)acryloyl groups in one molecule include bifunctional (meth)acrylates such as tricyclodecane dimethanol diacrylate, pentaerythritol di(meth)acrylate, 1,6-hexanediol (meth)acrylate, 1,9-nonanediol diacrylate, 1,10-decanediol (meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, and dipropylene glycol diacrylate; and trifunctional or higher functional (meth)acrylates such as pentaerythritol tri(meth)acrylate, trimethylolpropane triacrylate, pentaerythritol tetra(meth)acrylate, dimethylolpropane tetraacrylate, dipentaerythritol hexa(meth)acrylate, isocyanuric acid tri(meth)acrylate, ethoxylated glycerin triacrylate, and ethoxylated pentaerythritol tetraacrylate.

[0024] The polyfunctional (meth)acrylate may be a urethane (meth)acrylate. The urethane (meth)acrylate may be a urethane di(meth)acrylate having two (meth)acryloyl groups, or may be one having three or more (meth)acryloyl groups. From the viewpoint of the hardness of the hard coat layer, the number of (meth)acryloyl groups in the urethane (meth)acrylate is preferably 3 or more, more preferably 4 to 15, and even more preferably 6 to 12. When the urethane (meth)acrylate oligomer is used, its molecular weight is, for example, 3,000 or less, preferably 500 to 2,500, and more preferably 800 to 2,000.

[0025] The content of the polyfunctional compound in the hard coat material is preferably 50 parts by weight or more, more preferably 60 parts by weight or more, and even more preferably 70 parts by weight or more, relative to 100 parts by weight of the total of the resin components (monomers, oligomers, and prepolymers that form the binder resin upon curing). If the content of the polyfunctional compound is within the above range, the hardness of the hard coat layer tends to be increased.

[0026] The hard coat material may contain a bifunctional compound and a trifunctional or higher functional compound as the polyfunctional compound. For example, an acrylic hard coat material may contain a bifunctional or higher functional (meth)acrylate and a trifunctional or higher functional (meth)acrylate. The higher the ratio of trifunctional or higher functional compounds contained in the hard coat material, the higher the hardness of the hard coat layer and the higher the hardness and indentation modulus of the anti-reflection film tend to be.

[0027] (inorganic oxide particles) By including inorganic oxide particles in the hard coat layer 11, the surface hardness of the hard coat layer 11 is increased, and irregularities are formed on the surface, improving adhesion to the antireflection layer 5 provided on the hard coat layer 11.

[0028] Examples of inorganic oxides include metal or semimetal oxides such as silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, titanium oxide, niobium oxide, zinc oxide, tin oxide, cerium oxide, and magnesium oxide. The inorganic oxide may also be a composite oxide of multiple (semi)metals. Among the inorganic oxides listed above, silicon oxide is preferred because it has a high adhesion-improving effect and has a small refractive index difference between the inorganic oxide particles and the binder resin, thereby increasing transparency. Functional groups such as acrylic groups and epoxy groups may be introduced onto the surfaces of the inorganic oxide particles to improve adhesion and affinity with the resin.

[0029] The particle diameter of the inorganic oxide particles is preferably 5 to 80 nm. When the hard coat layer 11 contains inorganic oxide particles with a particle diameter of 5 nm or more, an uneven shape that provides excellent adhesion to the antireflection layer 5 is formed on the surface of the hard coat layer 11. When the particle diameter of the inorganic oxide particles contained in the hard coat layer 11 is 80 nm or less, an increase in haze due to light scattering by the particles can be suppressed.

[0030] From the viewpoint of forming a hard coat layer 11 having a surface irregularity shape that provides excellent adhesion to the antireflection layer 5, low haze, and high transparency, the average primary particle diameter of the inorganic oxide particles is preferably 15 to 65 nm, more preferably 20 to 60 nm, even more preferably 25 to 55 nm, and may be 30 to 50 nm. The primary particle diameter of the fine particles is determined by the Coulter counter method, and the median value D50 in the particle size distribution is defined as the average primary particle diameter.

[0031] From the viewpoint of suppressing an increase in haze due to light scattering by particles, it is preferable that the hard coat layer 11 contains a small amount of coarse particles. The 90% particle size (D90) of the inorganic oxide particles contained in the hard coat layer 11 is preferably 100 nm or less, more preferably 80 nm or less, even more preferably 70 nm or less, and may be 65 nm or less or 60 nm or less. From the viewpoint of preventing aggregation, the 10% particle size (D10) of the inorganic oxide particles is preferably 5 nm or more, more preferably 10 nm or more, and may be 15 nm or more or 20 nm or more. In the cumulative particle size distribution (by weight) measured by the Coulter Counter method, D10 is the particle size that is 10% cumulative from the smallest particle size, and D90 is the particle size that is 90% cumulative from the smallest particle size. For example, when D90 is 100 nm or less, the amount of particles having a particle size of 100 nm or more is 10% or less by weight.

[0032] The shape of the inorganic oxide particles is not particularly limited, but is preferably a (nearly) spherical shape with an aspect ratio of 1.5 or less. The aspect ratio of the particles is more preferably 1.2 or less, and even more preferably 1.1 or less. By using spherical inorganic oxide particles, it becomes easier to form an uneven shape on the surface of the hard coat layer that has excellent adhesion to the antireflection layer.

[0033] The hard coat layer 11 may contain particles other than inorganic oxide particles (e.g., metal particles, organic particles). However, even when particles other than inorganic oxides are contained, it is preferable that the D90 and D10 of all particles contained in the first hard coat layer 11 are within the above ranges. From the viewpoints of improving adhesion to the anti-reflection layer, transparency, hardness, etc., it is preferable that the hard coat layer 11 does not contain organic particles, and even if it contains organic particles, it is preferable that the content of organic particles is less than the content of inorganic oxide particles. The content of organic particles in the hard coat layer is preferably 10% or less of the content of inorganic oxide particles, more preferably 5% or less, and may be 3% or less, 1% or less, or 0.

[0034] In the present invention, the hard coat layer 11 contains, as inorganic oxide particles, first type particles having a particle diameter of 40 to 80 nm and second type particles having a particle diameter of 5 to 35 nm. When the hard coat layer 11 contains first type particles having a relatively large particle diameter and second type particles having a relatively small particle diameter, the adhesion between the hard coat layer and the antireflection layer is improved, and the impact resistance of the antireflection film tends to be improved.

[0035] Particles with a particle diameter of 40 nm or more tend to align near the surface of the hard coat layer (a region approximately 100 nm deep from the interface with the anti-reflection layer), contributing to improved surface hardness and improved adhesion to the anti-reflection layer due to surface irregularities. However, particles with a particle diameter of 40 nm or more are less likely to be distributed in the subsurface region (a region approximately 200 to 600 nm deep from the surface of the hard coat layer). In particular, when the hard coat layer is 10 μm or thicker, the distribution density of inorganic oxide particles with a particle diameter of 40 nm or more in the region 200 to 600 nm deep tends to be low. While the presence of inorganic oxide particles in the surface layer of the hard coat layer improves adhesion and surface hardness, a small particle distribution in the subsurface tends to result in a low indentation modulus and insufficient impact resistance.

[0036] Particles with a particle size of 35 nm or less tend to be distributed not only in the surface layer of the hard coat layer but also in the layers below it, so anti-reflection films whose hard coat layer contains inorganic oxide particles with a particle size of 35 nm or less have a high indentation modulus and excellent impact resistance. However, the surface irregularities formed by particles with a particle size of 35 nm or less tend to be small (the arithmetic mean height Sa of the hard coat layer surface is small), which tends to result in insufficient adhesion between the hard coat layer and the anti-reflection layer.

[0037] When the hard coat layer 11 contains first-type particles with a relatively large particle size and second-type particles with a relatively small particle size, the first-type particles tend to be distributed near the surface of the hard coat layer, and the second-type particles tend to be distributed in the layer below them, thereby suppressing the settling of inorganic oxide particles and providing an antireflection film with high adhesion between the hard coat layer and the antireflection layer, high indentation modulus, and excellent impact resistance.

[0038] The relatively large first type particles preferably have an average primary particle size of 40 to 70 nm, more preferably 45 to 60 nm, and the relatively small second type particles preferably have an average primary particle size of 15 to 35 nm, more preferably 20 to 30 nm.

[0039] When the particle diameters of the first type particles and the second type particles are close to each other, or conversely, when the particle diameters of the first type particles and the second type particles are significantly different, the effect of inhibiting particle sedimentation tends to be limited. Therefore, the average primary particle diameter of the first type particles is preferably 1.5 to 1.9 times, and more preferably 1.6 to 1.8 times, the average primary particle diameter of the second type particles.

[0040] The amount of the first type particles relative to the total amount of the first type particles and the second type particles is preferably 5 to 80% by weight, more preferably 10 to 70% by weight, even more preferably 15 to 60% by weight, and may be 20 to 50% by weight or 25 to 48% by weight. The higher the proportion of the first type particles, which have a relatively large particle size, the larger the arithmetic mean height Sa of the hard coat layer surface and the higher the adhesion of the antireflection layer tends to be. On the other hand, if the proportion of the first type particles is excessively high, the indentation modulus tends to be small and the impact resistance tends to be insufficient.

[0041] The content of inorganic oxide particles is preferably 20% by weight or more relative to the total solid content (total of binder and particles) of the hard coat layer 11. The content of inorganic oxide particles in the hard coat layer 11 is more preferably 25% by weight or more, further preferably 30% by weight or more, and may be 35% by weight or more, 40% by weight or more, or 45% by weight or more.

[0042] When the content of inorganic oxide particles having a particle size in the range of 5 to 80 nm is 20 wt % or more, the proportion of particles near the surface of the hard coat layer 11 (the interface on the anti-reflection layer 5 side) is high, which tends to form uniform unevenness throughout the entire surface of the hard coat layer 11, increase the arithmetic mean height Sa, and improve adhesion to the anti-reflection layer 5. Furthermore, when the hard coat layer contains first-type particles with relatively large particle sizes and second-type particles with relatively small particle sizes, the first-type particles tend to be aligned near the surface, while the second-type particles exist in the layer below them, which acts to suppress the settling of the first-type particles. This tends to increase the proportion of particles in the region approximately 600 nm from the surface of the hard coat layer and increase the indentation modulus. Even when the hard coat layer contains first-type and second-type particles with different particle sizes, if the content of inorganic oxide particles in the hard coat layer is less than 20%, the proportion of particles in the surface layer and the layer below is low, which tends to result in insufficient adhesion and impact resistance.

[0043] If the content of inorganic oxide particles in the hard coat layer is too high, the dispersibility of the particles and the transparency of the hard coat layer may be reduced. Therefore, the content of inorganic oxide particles in the hard coat layer 11 is preferably 70% by weight or less, more preferably 65% ​​by weight or less, and may be 60% by weight or less or 55% by weight or less.

[0044] (Formation of hard coat layer) The hard coat composition contains the above-mentioned binder resin component and inorganic oxide particles, and optionally a solvent capable of dissolving the binder resin component. When the binder resin component is a curable resin, it is preferable that an appropriate polymerization initiator is contained in the composition. For example, when the binder resin component is a photocurable resin, it is preferable that a photopolymerization initiator is contained in the composition. In addition to the above, the hard coat composition may contain additives such as a leveling agent, a thixotropic agent, an antistatic agent, an antiblocking agent, a dispersant, a dispersion stabilizer, an antioxidant, an ultraviolet absorber, an antifoaming agent, a thickener, a surfactant, and a lubricant.

[0045] A hard coat layer is formed by applying a hard coat composition to a film substrate, removing the solvent as necessary, and curing the resin. The hard coat composition can be applied by any suitable method, such as bar coating, roll coating, gravure coating, rod coating, slot orifice coating, curtain coating, fountain coating, or comma coating. The heating temperature after application may be set appropriately depending on the composition of the hard coat composition, and is, for example, about 50°C to 150°C. When the binder resin component is a photocurable resin, photocuring is carried out by irradiating it with active energy rays such as ultraviolet light. The integrated light intensity of the irradiated light is preferably 100 to 500 mJ / cm. 2 That's about it.

[0046] Before forming the antireflection layer 5 on the hard coat layer 11, the hard coat layer 11 may be subjected to a surface treatment. Examples of surface treatments include corona treatment, plasma treatment, flame treatment, ozone treatment, glow discharge treatment, alkali treatment, acid treatment, and treatment with a coupling agent, among other surface modification treatments. Vacuum plasma treatment may also be performed as the surface treatment. The surface roughness of the hard coat layer can also be adjusted by vacuum plasma treatment. For example, if vacuum plasma treatment is performed at high discharge power, the resin component on the surface of the hard coat layer is likely to be selectively etched, while inorganic oxide particles are largely left unetched. This increases the proportion of inorganic oxide particles at and near the surface of the hard coat layer, and tends to increase the arithmetic mean height Sa of the hard coat layer surface.

[0047] The atmospheric gas in the vacuum plasma treatment is preferably an inert gas such as helium, neon, argon, krypton, xenon, or radon, with argon being particularly preferred. The discharge power in the vacuum plasma treatment is, for example, about 0.08 to 4 kW. If the discharge power is excessively high, etching of the binder resin proceeds excessively, which may result in coarsening of the irregularities on the surface of the hard coat layer and easy detachment of inorganic oxide particles, resulting in a decrease in adhesion. The treatment time is preferably about 0.05 to 1.0 seconds, more preferably 0.1 to 0.6 seconds. The energy density during discharge is 0.1 to 5.0 kW / m 2 The preferred range is 0.15 to 2.0 kW / m 2 is more preferred.

[0048] (Hard Coat Layer Characteristics) As described above, by including inorganic oxide particles, a hard coat layer 11 having surface irregularities is formed, and by forming the antireflection layer 5 and the antifouling layer 7 thereon, an antireflection film having excellent interlayer adhesion is obtained. From the viewpoint of improving adhesion to the antireflection layer 5, the arithmetic mean height Sa of the surface of the hard coat layer 11 (the surface on which the antireflection layer 5 is formed) is preferably 2.6 nm or more, more preferably 2.8 nm or more, even more preferably 3.0 nm or more, and may be 3.1 nm or more or 3.2 nm or more.

[0049] The larger the arithmetic mean height Sa of the hard coat layer 11 surface, the more likely it is that the adhesion to the antireflection layer 5 improves, but if the surface irregularities of the hard coat layer become too large, sufficient adhesion may not be achieved. Therefore, the arithmetic mean height Sa of the hard coat layer surface is preferably 6 nm or less, more preferably 5 nm or less, even more preferably 4.5 nm or less, and may be 4.0 nm or less, 3.8 nm or less, 3.7 nm or less, or 3.6 nm or less.

[0050] The arithmetic mean height Sa is calculated in accordance with ISO 25178 from an image of a 1 μm square observed using an atomic force microscope (AFM).

[0051] As described above, by adjusting the particle size and content of the inorganic oxide particles, it is possible to adjust the uneven shape of the surface of the hard coat layer 11. The arithmetic mean height Sa of the hard coat layer 11 can also be increased by dry etching such as plasma treatment.

[0052] From the viewpoint of increasing the surface hardness, the thickness of the hard coat layer 11 is preferably 5 μm or more, more preferably 8 μm or more, and even more preferably 10 μm or more. The thicker the hard coat layer 11, the higher the pencil hardness of the anti-reflection film tends to be. The thickness of the hard coat layer may be 12 μm or more or 14 μm or more. If the thickness of the hard coat layer is increased to 10 μm or more in order to increase the surface hardness, the indentation modulus may decrease and impact resistance may be insufficient. However, as described above, by including first-type particles with a relatively large particle size and second-type particles with a relatively small particle size as inorganic oxide particles in the hard coat layer, it is possible to achieve both increased surface hardness and good adhesion and impact resistance.

[0053] From the viewpoint of hardness, there is no particular upper limit to the thickness of the hard coat layer 11, but an excessively thick hard coat layer may cause a decrease in transparency due to an increase in haze, or a decrease in adhesion of the antireflection layer due to a smoothing of the surface shape (a decrease in Sa). Therefore, the thickness of the hard coat layer 11 is preferably 25 μm or less, and may be 22 μm or less, 20 μm or less, or 18 μm or less.

[0054] From the viewpoints of increasing the surface hardness, increasing the indentation modulus of the antireflection film, and improving impact resistance, the hard coat layer 11 preferably has a large amount of inorganic oxide particles not only in the surface region near the interface with the antireflection layer 5, but also in a region approximately 200 to 600 nm deep from the interface with the underlying antireflection layer 5. In the cross section of the antireflection film, the area ratio occupied by inorganic oxide particles in the region 200 to 600 nm deep from the surface of the hard coat layer 11 facing the antireflection layer 5 is preferably 45% or more, more preferably 50% or more, even more preferably 52% or more, and may even be 54% or more or 55% or more. The area ratio occupied by inorganic oxide particles in the region 200 to 600 nm deep from the surface of the hard coat layer 11 facing the antireflection layer 5 may be 95% or less, 90% or less, 85% or less, 80% or less, 75% or less, or 70% or less.

[0055] The area ratio of inorganic oxide particles in the cross section of the hard coat layer is determined by image analysis of the image obtained by electron microscopy of a cross section 200 to 600 nm deep (400 nm in the depth direction) from the surface of the hard coat layer and 1000 nm in the surface direction (horizontal direction). Cross-sectional images of four locations on the anti-reflection film are obtained, and each cross-sectional image is binarized to identify the area occupied by the particles. The area ratio of particles in each cross-sectional image is calculated, and the average value is used as the area ratio occupied by the particles.

[0056] [Anti-reflection layer] The antireflection film 100 includes an antireflection layer 5 on the hard coat layer 11 of the hard coat film 1. The antireflection layer 5 is a laminate of multiple thin films with different refractive indices, and the optical film thickness (product of refractive index and thickness) of the thin films is adjusted so that the reversed phases of incident light and reflected light cancel each other out. Because the antireflection layer 5 is a multilayer laminate of multiple thin films with different refractive indices, it is possible to reduce reflectance over a wide wavelength range of visible light.

[0057] Examples of materials for the thin films constituting the antireflection layer 5 include metal oxides, nitrides, and fluorides. The antireflection layer 5 is preferably an alternate laminate of high-refractive index layers and low-refractive index layers. In order to reduce reflection at the interface with the antifouling layer, the thin film 34 provided as the outermost layer of the antireflection layer 5 is preferably a low-refractive index layer.

[0058] The high-refractive-index layers 31, 33 have a refractive index of, for example, 1.9 or more, preferably 2.0 or more. Examples of high-refractive-index materials include titanium oxide, niobium oxide, zirconium oxide, tantalum oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and antimony-doped tin oxide (ATO). Titanium oxide or niobium oxide is preferred. The low-refractive-index layers 32, 34 have a refractive index of, for example, 1.6 or less, preferably 1.5 or less. Examples of low-refractive-index materials include silicon oxide, titanium nitride, magnesium fluoride, barium fluoride, calcium fluoride, hafnium fluoride, and lanthanum fluoride. Silicon oxide is preferred. It is particularly preferred to alternately stack niobium oxide (Nb2O5) thin films 31, 33 as high-refractive-index layers and silicon oxide (SiO2) thin films 32, 34 as low-refractive-index layers. In addition to the low-refractive-index and high-refractive-index layers, a medium-refractive-index layer with a refractive index of approximately 1.6 to 1.9 may be provided.

[0059] The thickness of each of the high-refractive-index layer and the low-refractive-index layer is about 5 to 200 nm, preferably about 15 to 150 nm. The thickness of each layer can be designed so that the reflectance of visible light is low, depending on the refractive index, layer structure, etc. For example, the layer structure of the high-refractive-index layer and the low-refractive-index layer can be a four-layer structure consisting of, from the hard coat film 1 side, a high-refractive-index layer 31 with an optical thickness of about 25 nm to 55 nm, a low-refractive-index layer 32 with an optical thickness of about 35 nm to 55 nm, a high-refractive-index layer 33 with an optical thickness of about 80 nm to 240 nm, and a low-refractive-index layer 34 with an optical thickness of about 120 nm to 150 nm.

[0060] The antireflection layer 5 preferably has a primer layer 30 on the surface in contact with the hard coat layer 11, and a high refractive index layer and a low refractive index layer thereon. By providing the primer layer 30 in contact with the hard coat layer 11, which has surface irregularities formed by inorganic oxide particles, and forming a multilayer film of a high refractive index layer and a low refractive index layer that fulfills an antireflection function on the primer layer 30, an antireflection film with excellent interlayer adhesion and in which peeling of the antireflection layer is unlikely to occur can be obtained.

[0061] Examples of materials constituting the primer layer 30 include inorganic materials such as metals such as silicon, nickel, chromium, tin, indium, gold, silver, platinum, zinc, titanium, tungsten, aluminum, zirconium, and palladium; alloys of these metals; and oxides, fluorides, sulfides, and nitrides of these metals. Among these, oxides are preferred as the inorganic material for the primer layer, and those containing metals such as Si, In, Sn, Zn, and Ti are particularly preferred. The primer layer 30 may be an inorganic oxide layer having a lower oxygen content than the stoichiometric composition.

[0062] The thickness of the primer layer 30 is, for example, about 1 to 20 nm, preferably 2 to 15 nm, and more preferably 3 to 10 nm. When the thickness of the primer layer is within the above range, both adhesion to the hard coat layer 11 and high light transmittance can be achieved.

[0063] The method for forming the thin film constituting the antireflection layer 5 is not particularly limited, and either a wet coating method or a dry coating method may be used. Dry coating methods such as vacuum deposition, CVD, sputtering, and electron beam vapor deposition are preferred because they can form a thin film with a uniform thickness. Of these, sputtering is preferred because it has excellent uniformity in thickness and is easy to form a dense film.

[0064] In the sputtering method, a thin film can be continuously deposited while a long film is transported in one direction (longitudinal direction) using a roll-to-roll method. In the sputtering method, film deposition is carried out while an inert gas such as argon, and optionally a reactive gas such as oxygen, is introduced into the chamber. Deposition of an oxide layer by sputtering can be carried out using either an oxide target or reactive sputtering using a metal target. Reactive sputtering using a metal target is preferred for depositing metal oxide films at a high rate.

[0065] [Anti-fouling layer] The antireflection film has an antifouling layer 7 as the outermost layer (topcoat layer) on the antireflection layer 5. By providing the antifouling layer on the outermost surface, the influence of contamination from the external environment (fingerprints, dirt, dust, etc.) can be reduced and contaminants adhering to the surface can be easily removed.

[0066] In order to maintain the antireflection properties of the antireflection layer 5, it is preferable that the antifouling layer 7 has a small difference in refractive index from the low refractive index layer 34 on the outermost surface of the antireflection layer 5. The refractive index of the antifouling layer 7 is preferably 1.6 or less, more preferably 1.55 or less.

[0067] The material for the anti-fouling layer is preferably a fluorine group-containing silane compound or a fluorine group-containing organic compound. The anti-fouling layer can be formed by a wet method such as reverse coating, die coating, or gravure coating, or a dry method such as CVD. The thickness of the anti-fouling layer is usually about 1 to 100 nm, preferably 2 to 50 nm, and more preferably 3 to 30 nm.

[0068] [Characteristics of anti-reflective film] The arithmetic mean height Sa of the surface of the antireflection film (the surface of the antifouling layer 7) is preferably 2.6 nm or more, more preferably 2.8 nm or more, even more preferably 3.0 nm or more, and may be 3.1 nm or more or 3.2 nm or more. The arithmetic mean height Sa of the surface of the antireflection film is preferably 6 nm or less, more preferably 5 nm or less, even more preferably 4.5 nm or less, and may be 4.0 nm or less, 3.8 nm or less, 3.7 nm or less, or 3.6 nm or less.

[0069] As described above, the hard coat layer 11 contains inorganic oxide particles and has an uneven surface. Because the antireflection layer 5 and antifouling layer 7 formed on the hard coat layer 11 have small thicknesses, the surface of the antifouling layer 7 is likely to have an uneven surface that reflects the surface shape of the hard coat layer 11. By adjusting the particle size and blending amount of the fine particles in the hard coat layer 11 to adjust the surface shape of the hard coat layer, an antireflection film can be obtained in which the surface of the antifouling layer 7 has the above-mentioned Sa. As described above, the surface shape may be adjusted by subjecting the hard coat layer 11 to a surface treatment such as vacuum plasma treatment.

[0070] The haze of the antireflection film is preferably 1.5% or less, more preferably 1.2% or less, and even more preferably 1.0% or less. When the antireflection film is placed on the outermost surface of an image display device, a low haze results in clear image quality. Because the antireflection layer 5 and the antifouling layer 7 are thin and produce almost no haze, the haze of the antireflection film is approximately equal to the haze of the hard coat film. As mentioned above, the smaller the particle size and content of the inorganic oxide particles contained in the hard coat layer, the less light scattering occurs due to the particles, and the lower the haze tends to be.

[0071] The pencil hardness of the antifouling layer surface of the antireflection film is preferably 2H or more, more preferably 3H or more, even more preferably 4H or more, and may be 5H or more. By selecting a hard coat material, the hardness of the hard coat layer is increased, and accordingly, the pencil hardness of the antireflection film tends to increase. Furthermore, the thicker the hard coat layer, the higher the pencil hardness and the more improved the scratch resistance.

[0072] The indentation modulus of the surface of the antifouling layer of the antireflection film is preferably 10.0 GPa or more. The higher the indentation modulus of the antireflection film, the better the impact resistance tends to be, and the occurrence of scratches, cracks, peeling, etc. of the antireflection layer and the antifouling layer due to an impact such as dropping the device is suppressed.

[0073] The indentation modulus of an anti-reflection film is determined from the slope of the unloading curve at a depth of approximately 200 nm when an indentation test is performed by pressing the indenter of a nanoindenter into the surface of the anti-fouling layer of a sample in which the film substrate side of the anti-reflection film is bonded to the surface of a polarizing plate via an adhesive.

[0074] By selecting a hard coat material, the indentation modulus of the hard coat layer can be increased, which tends to increase the indentation modulus of the antireflection film. Furthermore, the indentation modulus tends to increase as the abundance (area ratio) of inorganic oxide particles in the cross section of the hard coat layer at a depth of 200 to 600 nm from the surface on the antireflection layer side increases.

[0075] [Usage of anti-reflective film] Antireflection films are used by being disposed on the surface of image display devices such as liquid crystal displays, organic EL displays, etc. For example, by disposing an antireflection film on the viewer-side surface of a panel including an image display medium such as a liquid crystal cell or an organic EL cell, reflection of external light can be reduced, thereby improving the visibility of the image display device.

[0076] By adjusting the blending ratio of inorganic oxide particles contained in the hard coat layer 11, the antireflection film of the present invention has high adhesion between the hard coat layer 11 and the antireflection layer 5, a high indentation modulus, and excellent impact resistance. Furthermore, by providing the antifouling layer 7 on the antireflection layer 5, the film is less susceptible to contamination from the external environment and can remove contaminants adhering to the surface. Therefore, the antireflection film is also suitable for use in image display devices that do not have a rigid cover layer such as glass.

[0077] As described above, a laminate of multiple films may be used as the film substrate 10, and the hard coat layer 11, antireflection layer 5, and antifouling layer 7 may be formed thereon. Alternatively, after the hard coat layer 11, antireflection layer 5, and antifouling layer 7 are formed on the film substrate 10, another film may be laminated to the surface of the film substrate 10 on which the hard coat layer is not formed. For example, a polarizer may be laminated to the surface of the film substrate 10 on which the hard coat layer is not formed, thereby forming a polarizing plate with an antireflection layer. The polarizing plate with an antireflection layer may be one in which a film substrate of an antireflection film is laminated to a polarizer, or one in which a polarizer protective film is laminated to a polarizer, and an antireflection film is laminated to the polarizer protective film. [Example]

[0078] The present invention will be explained in more detail below by giving examples of the preparation of anti-reflection films, but the present invention is not limited to the following examples.

[0079] [Preparation of hard-coated film] <Preparation of Hard Coat Composition> A hard coat composition was prepared by adding and mixing an organosilica sol to an ultraviolet-curable acrylic resin composition (GRANDIC PC-1070 manufactured by DIC). The organosilica sol contained silica particles with average primary particle diameters of 10 nm, 30 nm, 50 nm, and 100 nm, blended in the ratios shown in Table 1. The amount of organosilica sol was adjusted so that the amount of silica particles relative to the total solid content of the hard coat layer (total of resin and particles) would be the particle content shown in Table 1.

[0080] <Formation of hard coat layer> The above composition was applied to one side of an 80 μm thick triacetyl cellulose (TAC) film (Fujifilm Corporation, "Fujitac") so that the thickness after drying would be the value shown in Table 1, and then dried at 80° C. for 3 minutes. The applied layer was then cured by irradiating it with ultraviolet light using a high-pressure mercury lamp to form a hard coat layer.

[0081] [Preparation of anti-reflection film] After the hard coat layer of the above hard coat film was surface-treated, an antireflection layer and an antifouling layer were formed in this order on the hard coat layer to prepare an antireflection film.

[0082] <Surface treatment of hard coat layer> While the above hard coat film was being transported under a vacuum atmosphere of 0.5 Pa, the surface of the hard coat layer was subjected to argon plasma treatment with a discharge power of 0.2 kW.

[0083] <Formation of anti-reflection layer> The plasma-treated hard coat film was introduced into a roll-to-roll sputtering deposition device, and the chamber was heated to 1×10 -4 After reducing the pressure to 0.4 Pa, argon gas and oxygen gas were introduced at a volume ratio of 85:15 while the film was running, so that the pressure became 0.4 Pa, and an ITO primer layer with a thickness of 3 nm was formed by DC sputtering at a substrate temperature of 20°C. A sintered target containing indium oxide and tin oxide at a weight ratio of 90:10 was used as the target material to form the ITO primer layer.

[0084] Next, an anti-reflection layer was formed on the ITO primer layer by sequentially depositing a 16 nm Nb2O5 layer, a 19 nm SiO2 layer, a 102 nm Nb2O5 layer, and a 71 nm SiO2 layer. A Nb target was used to deposit the Nb2O5 layer, and a Si target was used to deposit the SiO2 layer. Argon and oxygen were used as sputtering gases to deposit the Nb2O5 and SiO2 layers, and the amount of oxygen introduced was adjusted using plasma emission monitoring (PEM) control to maintain the deposition mode in the transition region.

[0085] <Formation of anti-fouling layer> A 9 nm thick antifouling layer was formed on the antireflection layer by vacuum deposition using a dried and solidified fluorine-based antifouling coating agent (KY1903-1 manufactured by Shin-Etsu Chemical Co., Ltd.) as the deposition source.

[0086] [evaluation] <Particle ratio on the surface of the hard coat layer> Cross-sectional specimens were prepared from antireflection films using a focused ion beam (FIB) microsampling method with a Hitachi High-Technologies FB2200 integrated ion beam processing and observation system. FE-TEM analysis was performed using a field emission transmission electron microscope (JEOL JEM-2800) at an accelerating voltage of 200 kV and a magnification of 30,000x. Four randomly selected areas measuring 400 nm (depth) x 1000 nm (surface) were selected from the antireflection layer (primer layer) to the hard coat layer, ranging from a depth of 200 to 600 nm. Silica particles were identified and binarized using image processing software (Image-J) to determine the particle area ratio in each area. The average of the four areas was used as the particle area ratio on the hard coat layer surface.

[0087] <Arithmetic mean height Sa> The three-dimensional surface shape of the antifouling layer surface of the antireflection film was measured using an atomic force microscope (AFM) under the following conditions, and the arithmetic mean height Sa was measured in accordance with ISO 25178. Device: Bruker Dimemsion 3100, Controller: Nanoscope V Measurement mode: Tapping mode Cantilever: Si single crystal Measurement field of view: 1 μm x 1 μm

[0088] <Pencil hardness> A polarizing plate (manufactured by Nitto Denko Corporation) with transparent protective films attached to both sides of a polyvinyl alcohol polarizer was attached to the film substrate side of the antireflection film via a transparent acrylic adhesive to produce a polarizing plate with an antireflection film. Using this polarizing plate with an antireflection film as a sample, the pencil hardness of the antireflection film (antifouling layer) surface was measured under a load of 500 g in accordance with the pencil hardness test of JIS K5600-5-4.

[0089] <Indentation elastic modulus> A sample, with the film substrate side of the anti-reflection film attached to a glass slide via a transparent acrylic adhesive, was fixed with the antifouling layer facing up on the stage of a nanoindenter (Hysitron "Ti950 TriboIndenter"). Under a measurement environment of 23°C and 50% relative humidity, a Birco pitch (triangular pyramid) diamond indenter (tip curvature radius: 0.1 μm) was used to indent the sample to a depth of 200 nm at a rate of 20 nm / s, and then withdrawn at a rate of 20 nm / s. From the unloading curve, the indentation modulus Er at a depth of approximately 200 nm was calculated using the following formula:

[0090] Er=(S√π) / (2√A) S: Slope of the unloading curve π: Pi A: Projected contact area between the indenter and the sample The projected contact area A between the indenter and the sample was determined by the method described in Japanese Patent Application Laid-Open No. 2005-195357.

[0091] <Haze> The haze of the anti-reflection film was measured in accordance with JIS K7136 by irradiating light from the surface on the anti-fouling layer side using a haze meter ("HM-150" manufactured by Murakami Color Research Laboratory).

[0092] <Adhesion> A glass plate was attached to the surface of the anti-reflection film on the film substrate side (the surface without the anti-reflection layer) via a transparent acrylic adhesive, and the black panel temperature was measured at 85°C, humidity at 45%, and radiation intensity at 1500 W / m using an Iwasaki Electric metal halide weather meter "SUV-W161." 2 An accelerated weathering test was carried out for 32.5 hours under the conditions.

[0093] After the accelerated weathering test, 100 squares were cut at 1 mm intervals on the surface of the antifouling layer side of each sample. 2 mL of isopropyl alcohol was dropped onto the square area, and a polyester knit wiper (Berkshire "SuperPolx1200JSR") was slid back and forth 10 times over the area of ​​the square with a contact area of ​​10 mm x 10 mm, a load of 2.5 kg, and a sliding speed of 50 mm / s. The number of squares in which the antifouling layer and antireflection layer had peeled off over at least half of the square area was counted. For specimens with fewer than 50 peeled squares, an additional 40 strokes (50 strokes in total) were performed and similar evaluations were conducted. For specimens with fewer than 50 peeled squares, an additional 50 strokes (100 strokes in total) were performed and similar evaluations were conducted. Adhesion was evaluated according to the following criteria. A: The number of peeled cross-cuts is less than 50 in 100 round trip tests B: 50 or more peeled squares in 100 back-and-forth tests, less than 50 peeled squares in 50 back-and-forth tests C: 50 or more peeled squares in 50 back-and-forth tests, less than 50 peeled squares in 10 back-and-forth tests D: 50 or more peeled squares in 10 round trip tests

[0094] <Impact resistance>

[0095] The film substrate side of the anti-reflection film was attached to a 5 cm square black acrylic plate (1 mm thick) via a 15 μm thick transparent acrylic adhesive (Component A). A 5 cm square polystyrene sheet (manufactured by Sanko Soken, 0.4 mm thick) was cut out in the center using a utility knife to create a 1 cm square hole, and the processed portion on one side was sanded with #2000 sandpaper to remove surface burrs and smooth the surface. A 5 cm square black acrylic plate (1 mm thick) was attached to the unsmoothed side of this polystyrene sheet via a 15 μm thick transparent acrylic adhesive (Component B). Component A and Component B were overlapped so that the anti-reflection film of Component A faced the smoothed side of the polystyrene sheet of Component B, and the four edges were secured in place with tape to prepare a measurement sample.

[0096] Impact tests were conducted using a DuPont impact tester (Toyo Seiki Seisakusho, No. 451). A 1 mm thick acrylic plate was placed on the tester, and the above-mentioned test sample was placed on top of it, with component B facing up (no support). A 10 mm diameter metal cylinder was placed at the center of the test sample (at the hole in the polystyrene sheet), and a 6.35 mm radius impact die was placed on top of it. A 100 g weight was dropped from a height of 200 mm to apply impact. After 35 impact tests, components A and B were separated, and an LED light was shone on the anti-reflection film surface of component A to visually inspect for scratches. Components A and B were then re-fixed and subjected to 10 more impact tests (a total of 45 tests), and the presence or absence of scratches was confirmed. Impact resistance was evaluated according to the following criteria based on the number of tests required until scratches appeared on the anti-reflection film. A: No scratches were observed even after 45 tests B: No scratches occurred after 35 tests, but scratches occurred after 45 tests C: Scratches occurred after 35 tests [Evaluation results] Table 1 shows the structure of the hard coat layer in the antireflection films of Samples 1 to 15 (the content of silica particles, the blending ratio of silica particles, and the thickness of the hard coat layer), as well as the evaluation results of the antireflection films.

[0097] [Table 1]

[0098] The antireflection film of Sample 1, whose hard coat layer contained silica particles with an average primary particle diameter of 100 nm, had an indentation modulus of less than 10 GPa and insufficient impact resistance. Furthermore, the antireflection film of Sample 1 had a small Sa on the surface of the antifouling layer, and the adhesion of the antireflection layer was insufficient.

[0099] The anti-reflection films of Samples 2 and 3, in which the hard coat layer contained silica particles with an average primary particle size of 50 nm, had an indentation modulus of less than 10 GPa, similar to Sample 1, and were insufficient in impact resistance.

[0100] The antireflection film of sample 14, whose hard coat layer contained silica particles with an average primary particle diameter of 30 nm, exhibited good impact resistance, but the Sa of the antifouling layer surface was small and the adhesion of the antireflection layer was insufficient.The antireflection film of sample 15, whose hard coat layer contained silica particles with an average primary particle diameter of 10 nm, exhibited a smaller Sa of the antifouling layer surface than sample 14, and the adhesion of the antireflection layer was even worse.

[0101] The anti-reflection film of Sample 4, whose hard coat layer contained silica particles with an average primary particle diameter of 30 nm and silica particles with an average primary particle diameter of 50 nm, had surface hardness and adhesion equivalent to those of Sample 3, which used only silica particles with an average primary particle diameter of 50 nm. Furthermore, compared to Sample 3, Sample 4 had a significantly higher particle area ratio on the hard coat layer surface, a higher indentation modulus, and improved impact resistance.

[0102] The anti-reflection films of Samples 6, 11, and 13, which had different ratios of silica particles with an average primary particle diameter of 30 nm and silica particles with an average primary particle diameter of 50 nm, had excellent surface hardness, adhesion, and impact resistance, similar to Sample 4. A comparison of Samples 4, 6, 11, and 13 reveals that the higher the ratio of particles with relatively small particle diameters, the larger the particle area ratio on the hard coat layer surface, and the correspondingly higher the indentation modulus. In particular, Samples 6 and 11 had excellent adhesion of the anti-reflection layer.

[0103] These results show that by using a combination of relatively large and relatively small particles as inorganic oxide microparticles contained in the hard coat layer, the proportion of particles near the surface of the hard coat layer increases, increasing the indentation modulus, and the effect of the relatively large particles increases the surface roughness (arithmetic mean height Sa), thereby achieving both adhesion and impact resistance of the anti-reflection layer.

[0104] Samples 5 and 7, which had thicker hard coat layers, had excellent adhesion and impact resistance of the antireflection layer, similar to samples 4, 6, 11, and 13. However, sample 5 had higher haze than sample 4, and sample 7 had a lower particle ratio on the hard coat layer surface and a lower indentation modulus than sample 4. On the other hand, sample 12 had low haze, similar to sample 11, and adhesion and impact resistance were comparable to those of sample 11.

[0105] Sample 10, in which the thickness of the hard coat layer was reduced, had excellent adhesion and impact resistance of the antireflection layer, similar to Samples 4, 6, 11, and 13, but the pencil hardness was 3H, indicating a decrease in surface hardness.

[0106] Sample 8, which had a smaller particle content than Sample 7, had the same excellent properties as Sample 7, but Sample 9, which had an even smaller particle content, had insufficient adhesion and impact resistance.

[0107] From the above results, it can be seen that by adjusting the particle size and blending amount of inorganic oxide particles contained in the hard coat layer of an antireflection film, an antireflection film having excellent adhesion between the hard coat layer and the antireflection layer and excellent impact resistance can be obtained. [Explanation of symbols]

[0108] 1. Hard coated film 10 Film substrate 11 Hard coat layer 5 Anti-reflection layer 30 primer layer 31,33 High refractive index layer 32,34 Low refractive index layer 100 Anti-reflective film

Claims

1. An antireflection film comprising: a hard coat film having a hard coat layer on one main surface of a film substrate; an antireflection layer provided on the hard coat layer; and an antifouling layer as an outermost surface layer provided on the antireflection layer, the antireflection layer is a laminate of a plurality of thin films having different refractive indices, the hard coat layer contains a binder resin and inorganic oxide particles, the content of the inorganic oxide particles in the hard coat layer is 20 to 80% by weight, the inorganic fine particles include first type particles having a particle diameter of 40 to 80 nm and second type particles having a particle diameter of 5 to 35 nm, and the average primary particle diameter of the first type particles is within a range of 1.5 to 1.9 times the average primary particle diameter of the second type particles; Anti-reflective film.

2. 2. The anti-reflection film according to claim 1, wherein the amount of the first type particles relative to the total amount of the first type particles and the second type particles is 5 to 80% by weight.

3. 2. The antireflection film according to claim 1, wherein the area ratio of the inorganic oxide particles in the hard coat layer is 45% or more in a cross section within a depth range of 200 to 600 nm from the surface on the antireflection layer side.

4. The antireflection film according to claim 1 , wherein the antifouling layer has an arithmetic mean height Sa of 2.6 nm or more.

5. 2. The antireflection film according to claim 1, wherein the surface on the antifouling layer side has an indentation elastic modulus of 10 GPa or more.

6. 2. The anti-reflective film according to claim 1, having a haze of 1.5% or less.

7. An image display device, comprising an image display medium and an anti-reflection film according to any one of claims 1 to 6 disposed on the viewing side surface thereof.

Images