JP2020067582A - Antireflection film - Google Patents

Abstract

To provide an antireflection film having excellent reflection characteristics (low reflectivity) in a broad band, with suppressed coloring.SOLUTION: An antireflection film comprises a transparent base material, and an adhesive layer, a first NbOlayer, a first SiOlayer, a second NbOlayer, a second SiOlayer, and an antifouling layer in this order from the transparent base material. The first NbOlayer has an optical film thickness of 28 nm to 33 nm, the first SiOlayer has an optical film thickness of 43 nm to 57 nm, the second NbOlayer has an optical layer thickness of 264 nm to 288 nm, and the second SiOlayer has an optical film thickness of 113 nm to 129 nm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an antireflection film.

  BACKGROUND ART Conventionally, in order to prevent external light from being reflected on a display screen of a CRT, a liquid crystal display device, a plasma display panel, etc., an antireflection film arranged on the surface of the display screen has been widely used. As the antireflection film, for example, a multilayer film having a plurality of layers having different refractive indexes is known. It is known that high antireflection performance (low reflectance in a wide band) can be obtained by using such a multilayer film. The antireflection performance of the antireflection film is generally evaluated by the luminous reflectance Y (%), and the lower the luminous reflectance, the better the antireflection performance. However, there is a problem that the reflection hue tends to be colored when trying to lower the luminous reflectance.

Japanese Patent Laid-Open No. 11-204065 Patent No. 5249054

  The present invention has been made to solve the above conventional problems, and an object thereof is to have an excellent reflection characteristic (low reflection property) in a wide band, and an antireflection film in which coloring is suppressed. To provide.

The antireflection film of the present invention comprises a transparent base material, an adhesion layer, a first Nb ₂ O ₅ layer, a first SiO ₂ layer, a second and a second Nb _{2 in} order from the transparent base material. and O ₅ layer, a second SiO ₂ layer, and an antifouling layer in this order, the optical film thickness of the first _Nb 2 _{O 5} layer is 28Nm～33nm, optical of the first SiO ₂ layer The film thickness is 43 nm to 57 nm, the optical film thickness of the second Nb ₂ O ₅ layer is 264 nm to 288 nm, and the optical film thickness of the second SiO ₂ layer is 113 nm to 129 nm.
In one embodiment, the antifouling layer has a refractive index of 1.00 to 1.50.
In one embodiment, the thickness of the antifouling layer is 3 nm to 15 nm.
In one embodiment, the antireflection film has a maximum reflectance of 0.5% or less in a wavelength range of 420 nm to 660 nm.
In one embodiment, the transparent substrate contains a hard coat layer.
In one embodiment, the antireflection film further comprises an optical film on the surface of the transparent substrate opposite to the adhesion layer.
According to another aspect of the present invention, an image display device is provided. This image display device includes the antireflection film.

According to the present invention, by appropriately adjusting the optical film thicknesses of a plurality of Nb ₂ O ₅ layers and SiO ₂ layers arranged, it has excellent reflection characteristics (low reflectivity) in a wide band and is colored. A suppressed antireflection film can be provided.

1 is a schematic sectional view of an antireflection film according to one embodiment of the present invention. It is a reflectance spectrum of the antireflection film obtained by the Example and the comparative example.

A. Overview of Antireflection Film FIG. 1 is a schematic cross-sectional view of an antireflection film according to one embodiment of the present invention. The antireflection film 100 includes a transparent substrate 10, an adhesive layer 20, a first Nb ₂ O ₅ layer 30, a first SiO ₂ layer 40, and a second Nb _{2 in} order from the transparent substrate 10. It has an O ₅ layer 50, a second SiO ₂ layer 60, and an antifouling layer 70 in this order. Note that, in FIG. 1, the scales such as the thickness in the drawing are different from the actual scale in order to make it easy to see.

In the present invention, the optical film thickness (refractive index × physical film thickness) of the first Nb ₂ O ₅ layer is 28 nm to 33 nm. The optical film thickness of the first SiO ₂ layer is 43 nm to 57 nm. The optical film thickness of the second Nb ₂ O ₅ layer is 264 nm to 288 nm. The optical film thickness of the second SiO ₂ layer is 113 nm to 129 nm.

In the present invention, the first Nb ₂ O ₅ layer 30, the first SiO ₂ layer 40, the second Nb ₂ O ₅ layer 50, and the second SiO ₂ layer 60 are laminated in this order. Thereby, an antireflection film having excellent reflection characteristics (low reflectivity) can be obtained. Furthermore, by adjusting the optical film thickness of each layer within a specific range as described above, an antireflection film having a neutral reflection hue can be provided as an antireflection film having an antifouling layer. Further, by adjusting the optical film thickness of each layer within a specific range, it is possible to obtain an antireflection film that exhibits low reflectance with respect to incident light of short wavelength and long wavelength. As an antireflection film having an antifouling layer, it is one of the achievements of the present invention that an antireflection film capable of satisfying both excellent reflection characteristics (low reflectivity) in a wide band and neutral reflection hue can be provided. .

  The maximum value of the reflectance of the antireflection film in the wavelength range of 420 nm to 660 nm is 0.5% or less, preferably 0.4% or less, and more preferably 0.3% or less. The lower the “maximum value of reflectance in the wavelength range of 420 nm to 660 nm” is, the more preferable, but the lower limit thereof is, for example, 0.05% (preferably 0.03%). In this specification, the reflectance means the luminous reflectance Y. The measuring method will be described later.

  Although not shown, the antireflection film may further include any appropriate other layer or film. For example, an optical film may be arranged on the surface of the transparent substrate opposite to the adhesion layer.

  In one embodiment, an image display device including the antireflection film is provided. The image display device is not particularly limited, and examples thereof include a CRT, a liquid crystal display device, and a plasma display. In one embodiment, in the image display device, the antireflection film is provided on the outermost side on the viewing side.

B. Transparent Substrate The transparent substrate may be composed of any appropriate resin film as long as the effects of the present invention can be obtained. Specific examples of the resin constituting the resin film include a polyolefin resin (for example, polyethylene and polypropylene), a polyester resin (for example, polyethylene terephthalate and polyethylene naphthalate), and a polyamide resin (for example, nylon-6 and nylon-66). ), Polystyrene resin, polyvinyl chloride resin, polyimide resin, polyvinyl alcohol resin, ethylene vinyl alcohol resin, (meth) acrylic resin, (meth) acrylonitrile resin, cellulosic resin (for example, triacetyl cellulose, diacetyl cellulose, cellophane). Can be mentioned. The transparent substrate may be a single layer, a laminate of a plurality of resin films, or a laminate of a resin film (single layer or laminate) and the hard coat layer described below. . The transparent substrate (essentially the composition for forming the transparent substrate) may contain any suitable additive. Specific examples of the additives include antistatic agents, ultraviolet absorbers, plasticizers, lubricants, colorants, antioxidants, and flame retardants. The material forming the transparent base material is well known in the art, and thus detailed description thereof will be omitted.

  The transparent substrate can function as a hard coat layer in one embodiment. That is, the transparent substrate may be a laminate of a resin film (single layer or laminate) and a hard coat layer described below as described above, and the hard coat layer alone constitutes the transparent substrate. May be. When the transparent substrate is composed of a laminate of a resin film and a hard coat layer, the hard coat layer may be arranged adjacent to the adhesion layer. In one embodiment, the hard coat layer is a cured layer of any suitable ionizing radiation curable resin. Examples of ionizing rays include ultraviolet rays, visible light, infrared rays, and electron beams. It is preferably ultraviolet light, and therefore the ionizing radiation curable resin is preferably an ultraviolet light curable resin. Examples of the ultraviolet curable resin include (meth) acrylic resin, silicone resin, polyester resin, urethane resin, amide resin, and epoxy resin. For example, a representative example of the (meth) acrylic resin is a cured product (polymerized product) obtained by curing a polyfunctional monomer containing a (meth) acryloyloxy group with ultraviolet light. The polyfunctional monomers may be used alone or in combination of two or more. Any suitable photoinitiator may be added to the polyfunctional monomer. Since the material forming the hard coat layer is well known in the art, detailed description thereof will be omitted.

Any appropriate inorganic or organic fine particles can be dispersed in the hard coat layer. The particle size of the fine particles is, for example, 0.01 μm to 3 μm. Alternatively, an uneven shape can be formed on the surface of the hard coat layer. By adopting such a configuration, a light diffusing function generally called antiglare can be imparted. As the fine particles to be dispersed in the hard coat layer, silicon oxide (SiO ₂ ) can be preferably used from the viewpoint of refractive index, stability, heat resistance and the like. Further, the hard coat layer (essentially, the composition for forming the hard coat layer) may contain any appropriate additive. Specific examples of the additive include a leveling agent, a filler, a dispersant, a plasticizer, an ultraviolet absorber, a surfactant, an antioxidant, and a thixotropic agent.

  The hard coat layer preferably has a hardness of H or higher, more preferably 3H or higher in a pencil hardness test. The pencil hardness test can be measured according to JIS K 5400.

  The thickness of the transparent base material can be appropriately set depending on the purpose, the configuration of the transparent base material, and the like. When the transparent substrate is formed as a single layer or a laminate of resin films, the thickness is, for example, 10 μm to 200 μm. When the transparent substrate includes the hard coat layer or is composed of the hard coat layer alone, the thickness of the hard coat layer is, for example, 1 μm to 50 μm.

  The light transmittance of the transparent substrate is preferably 60% to 99%, more preferably 80% to 99%.

  The refractive index of the transparent substrate (when the transparent substrate has a laminated structure, the refractive index of the layer adjacent to the adhesion layer) is preferably 1.45 to 1.65, more preferably 1.50 to 1 .60. In the present specification, “refractive index” refers to a refractive index measured based on JIS K 7105 at a temperature of 25 ° C. and a wavelength of λ = 580 nm, unless otherwise specified.

C. Adhesion Layer The adhesion layer is a layer that can be provided to enhance the adhesion between adjacent layers (for example, the transparent substrate and the first Nb ₂ O ₅ layer). The adhesion layer may be composed of silicon, for example. The thickness of the adhesion layer is, for example, 2 nm to 5 nm.

The adhesion layer is between the transparent substrate and the first Nb ₂ O ₅ layer, and also between the first Nb ₂ O ₅ layer and the first SiO ₂ layer and between the first SiO ₂ layer and the second SiO ₂ layer. Between the _second Nb ₂ O ₅ layer and the second Nb ₂ O ₅ layer and the second SiO ₂ layer.

  The adhesion layer is typically formed by a dry process. Specific examples of the dry process include a PVD (Physical Vapor Deposition) method and a CVD (Chemical Vapor Deposition) method. Examples of the PVD method include a vacuum vapor deposition method, a reactive vapor deposition method, an ion beam assist method, a sputtering method, and an ion plating method. Examples of the CVD method include a plasma CVD method. When performing in-line processing, a sputtering method can be used suitably.

D. First Nb ₂ O ₅ Layer The first Nb ₂ O ₅ layer is composed of Nb ₂ O ₅ (refractive index: 2.34). In the present invention, the refractive index of the first Nb ₂ O ₅ layer (and the following first SiO ₂ layer, second Nb ₂ O ₅ layer and second SiO ₂ layer) is set to an appropriate value. Not only that, but by specifying the material forming the layer, an antireflection film having a neutral reflection hue can be obtained.

The first Nb ₂ O ₅ layer (and the following first SiO ₂ layer, second Nb ₂ O ₅ layer and second SiO ₂ layer) can be formed by a so-called dry process. Specific examples of the dry process include a PVD (Physical Vapor Deposition) method and a CVD (Chemical Vapor Deposition) method. Examples of the PVD method include a vacuum vapor deposition method, a reactive vapor deposition method, an ion beam assist method, a sputtering method, and an ion plating method. Examples of the CVD method include a plasma CVD method. In one embodiment, the sputtering method can be preferably used. By using the sputtering method, it is possible to reduce variations in reflected tint.

As described above, the optical film thickness of the first Nb ₂ O ₅ layer is 28 nm to 33 nm. The optical film thickness of the first Nb ₂ O ₅ layer is preferably 28 nm to 32 nm, more preferably 28 nm to 30 nm. Within such a range, an antireflection film having a neutral reflection hue can be obtained.

The ratio of the optical thickness of the first SiO ₂ layer to the optical thickness of the first Nb ₂ O ₅ layer is preferably 1.4 to 2.1, more preferably 1.7 to 2.1. is there. Within such a range, it is possible to obtain an antireflection film having excellent reflection characteristics and a neutral reflection hue.

The thickness of the first Nb ₂ O ₅ layer is preferably 12.0 nm to 14.1 nm, more preferably 12.0 nm to 13.7 nm, and further preferably 12.0 nm to 12.8 nm.

E. First SiO ₂ Layer The first SiO ₂ layer is composed of SiO ₂ (refractive index: 1.46).

As described above, the optical film thickness of the first SiO ₂ layer is 43 nm to 57 nm. Within such a range, an antireflection film having a neutral reflection hue can be obtained.

The ratio of the optical film thickness of the second Nb ₂ O ₅ layer to the optical film thickness of the first SiO ₂ layer is preferably 4.7 to 6.7, and more preferably 5.1 to 6.1. is there. Within such a range, it is possible to obtain an antireflection film having excellent reflection characteristics and a neutral reflection hue.

The thickness of the first SiO ₂ layer is preferably 29.5 nm to 39.0 nm.

F. Second Nb ₂ O ₅ Layer The second Nb ₂ O ₅ layer is composed of Nb ₂ O ₅ (refractive index: 2.34).

As described above, the optical film thickness of the second Nb ₂ O ₅ layer is 264 nm to 288 nm. Within such a range, an antireflection film having a neutral reflection hue can be obtained.

The ratio of the optical film thickness of the second SiO ₂ layer to the optical film thickness of the second Nb ₂ O ₅ layer is preferably 0.40 to 0.48, more preferably 0.43 to 0.44. is there. Within such a range, it is possible to obtain an antireflection film having excellent reflection characteristics and a neutral reflection hue.

The thickness of the second Nb ₂ O ₅ layer is preferably 112.8 nm to 123.1 nm.

G. Second SiO ₂ Layer The second SiO ₂ layer is composed of SiO ₂ (refractive index: 1.46).

As described above, the optical film thickness of the second SiO ₂ layer is 113 nm to 129 nm. Within such a range, an antireflection film having a neutral reflection hue can be obtained.

The thickness of the first SiO ₂ layer is preferably 77.4 nm to 88.4 nm.

H. Antifouling Layer The antifouling layer provided as needed is a layer capable of imparting water repellency, oil repellency, sweat resistance, antifouling property, etc. to the surface of the antireflection film. In the present invention, the presence of an antifouling layer is taken into consideration, and the above-mentioned inorganic layer (first Nb ₂ O ₅ layer, first SiO ₂ layer, second Nb ₂ O ₅ layer and second SiO ₂ layer). One of the features is that the optical film thickness of is adjusted.

A fluorine-containing compound is preferable as a material forming the antifouling layer. The fluorine-containing compound imparts antifouling property and can contribute to lowering the refractive index. Among these, a fluoropolymer having a perfluoropolyether skeleton is preferable because it has excellent water repellency and can exhibit high antifouling property. From the viewpoint of enhancing the antifouling property, perfluoropolyether having a main chain structure that can be rigidly arranged in parallel is particularly preferable. As the structural unit of the main chain skeleton of perfluoropolyether, perfluoroalkylene oxide which may have a branch having 1 to 4 carbon atoms is preferable, and examples thereof include perfluoromethylene oxide and (—CF ₂ O—). , perfluoro ethylene oxide _{(-CF 2} CF ₂ O-), perfluoro propylene oxide _{(-CF 2 CF 2 CF 2 O-} ), perfluoroisopropylene oxide _{(-CF (CF 3) CF 2} O-) and the like include To be

The antifouling layer has a refractive index of preferably 1.00 to 1.50, more preferably 1.10 to 1.50, and further preferably 1.20 to 1.45. Within such a range, the optical film thicknesses of the first Nb ₂ O ₅ layer, the first SiO ₂ layer, the second Nb ₂ O ₅ layer and the second SiO ₂ layer can be set within the above range. It is possible to provide an antireflection film that has a greater effect, has excellent reflection characteristics (low reflectivity) in a wide band, and has suppressed coloring.

In one embodiment, the antireflection film of the present invention is configured so that the difference between the refractive index of the antifouling layer and the refractive index of the second SiO ₂ layer is small. The difference between the refractive index of the antifouling layer and the refractive index of the second SiO ₂ layer (refractive index of the second SiO ₂ layer−refractive index of the antifouling layer) is preferably −0.1 to 0.3. Yes, more preferably -0.05 to 0.2, and further preferably 0 to 0.15.

The thickness of the antifouling layer is preferably 3 nm to 15 nm, more preferably 3 nm to 10 nm. Within such a range, it is possible to form an antifouling layer having little color unevenness and excellent antifouling performance. If the thickness of the antifouling layer is within the above range, the optical film thickness of the first Nb ₂ O ₅ layer, the first SiO ₂ layer, the second Nb ₂ O ₅ layer and the second SiO ₂ layer. It is possible to provide an antireflection film having an excellent reflection property (low reflectivity) in a wide band and being suppressed in coloring, by further increasing the effect of the above range.

  The method of forming the antifouling layer is, depending on the material to be formed, physical vapor deposition such as vapor deposition and sputtering, chemical vapor deposition, reverse coating, die coating, wet coating such as gravure coating, etc. Can be used.

I. Optical Film Examples of the optical film provided as necessary include a polarizing plate, a retardation film, a brightness enhancement film, a diffusion film, a conductive film and the like. The optical film may be laminated to the transparent substrate via any suitable pressure sensitive adhesive or adhesive.

  Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. The tests and evaluation methods in the examples are as follows. In addition, "%" in the examples is based on weight unless otherwise specified.

<Evaluation method>
(1) Physical thickness The thickness of each layer was measured by observing a TEM cross section.
(2) Refractive Index The refractive index of each layer was measured by a spectroscopic ellipsometer using an evaluation sample corresponding to each layer.
(3) Optical film thickness The optical film thickness was calculated by multiplying the physical thickness and the refractive index.
(4) Reflection characteristic E
A light-shielding black acrylic plate was attached to the transparent substrate side of the antireflection film via an adhesive to prepare an evaluation sample.
Then, the values of the luminous reflectance Y, the reflection L, the reflection hue a ^* , and the reflection hue b ^* of the antireflection surface were 5 ° specular reflection (wavelength: 380 nm to 780 nm) using a spectrophotometer “U4100” manufactured by Hitachi, Ltd. The measurement was carried out under the conditions of).
The E value was calculated by the following formula. The E value is an index for evaluating the tint, and the lower the E value is, the closer the reflection hue becomes to neutral.
The reflectance spectrum obtained in the above evaluation is shown in FIG.

[Example 1]
(Creation of transparent base material)
100 parts by weight of urethane acrylate resin (manufactured by Dainippon Ink and Chemicals, Inc., product name “UNIDIC V4025”, refractive index 1.52) and nano silica particles as inorganic particles (manufactured by Nissan Chemical Co., Ltd., product name “MEK-ST-L”) 50 parts by weight (average particle size 50 nm) and 5 parts by weight of BASF's trade name “Irgacure 184” as a UV initiator were mixed. Then, a mixed solution of MEK and PGM as a diluting solvent was added to the above solution to adjust the solvent ratio to MEK / PGM = 40/60 to obtain a composition for forming a hard coat layer.
The composition for forming a hard coat layer was applied to one side of a resin film (TAC: manufactured by Fuji Film Co., Ltd., trade name “TD80UL”) so that the thickness after drying was 5 μm, and dried at 80 ° C. for 2 minutes. After that, a high pressure mercury lamp was used to irradiate with ultraviolet rays having an integrated light amount of 300 mJ / cm ² to cure the coating layer and form a hard coat layer on the resin film.
(Formation of inorganic layer)
The Si sputtering target was set in a magnetron sputtering apparatus, and an adhesion layer (thickness 5 nm) composed of a SiOx layer was formed on the hard coat layer.
Next, the Nb target was set in a magnetron sputtering device and reactive sputtering was performed to form a first Nb ₂ O ₅ layer (thickness 12 nm, refractive index 2.34) on the adhesion layer.
Next, the Si target was set in a magnetron sputtering apparatus and reactive sputtering was performed to form a first SiO ₂ layer (thickness 39 nm, refractive index 1.46) on the first Nb ₂ O ₅ layer.
Then, a second Nb ₂ O ₅ layer (thickness 119 nm, refractive index 2.34) is formed on the first SiO ₂ layer by the same method as the method for forming the first Nb ₂ O ₅ layer. did. Further, a second SiO ₂ layer (thickness: 78 nm, refractive index 1.46) was formed on the second Nb ₂ O ₅ layer by the same method as the method for forming the first SiO ₂ layer.
(Formation of antifouling layer)
The second SiO ₂ layer on the fluorine-based resin (in the main chain skeleton _- (CF 2 _-CF 2 -O) - and - _(CF 2 -O) - fluororesin containing perfluoroether containing) solution Was coated by a gravure coating method to form an antifouling layer having a thickness of 9 nm and a refractive index of 1.32.
In this way, the transparent substrate (resin film / hard coat layer) / adhesion layer (SiOx layer) / first Nb ₂ O ₅ layer / first SiO ₂ layer / second Nb ₂ O ₅ layer / second An antireflection film having the structure of SiO ₂ layer / antifouling layer ₂ ) was obtained. The obtained antireflection film was subjected to the above evaluation. The results are shown in Table 1.

[Examples 2 to 6, Comparative Examples 1 to 6]
Implementation except that the thicknesses of the first Nb ₂ O ₅ layer, the first SiO ₂ layer, the second Nb ₂ O ₅ layer, the second SiO ₂ layer and the antifouling layer were set to the thicknesses shown in Table 1. An antireflection film was obtained in the same manner as in Example 1. The obtained antireflection film was subjected to the above evaluation. The results are shown in Table 1.

[Comparative Example 7]
A transparent substrate was prepared in the same manner as in Example 1.
Next, ZrO ₂ was set in a vacuum vapor deposition apparatus and vacuum vapor deposition was performed to form a first ZrO ₂ layer (thickness 13 nm, refractive index 2.22) on the transparent substrate.
Next, MgF ₂ was set in a vacuum vapor deposition apparatus and vacuum vapor deposition was performed to form a first MgF ₂ layer (thickness: 34 nm, refractive index: 1.38) on the first ZrO ₂ layer.
Then, a second ZrO ₂ layer (thickness 118 nm, refractive index 2.22) was formed on the first MgF ₂ layer by the same method as the method for forming the first ZrO ₂ layer. Further, a second MgF ₂ layer (thickness 91 nm, refractive index 1.38) was formed on the second ZrO ₂ layer by the same method as the method for forming the first MgF ₂ layer.
A second MgF ₂ layer on a fluorine-based resin (in the main chain skeleton _- (CF 2 _-CF 2 -O) - and - _(CF 2 -O) - fluororesin containing perfluoroether containing) solution Was coated by a gravure coating method to form an antifouling layer having a thickness of 5 nm and a refractive index of 1.32.
In this way, the transparent substrate (resin film / hard coat layer) / adhesion layer (SiOx layer) / first ZrO ₂ layer / first MgF ₂ layer / second ZrO ₂ layer / second MgF ₂ An antireflection film having a structure of (layer / antifouling layer) was obtained. The obtained antireflection film was subjected to the above evaluation. The results are shown in Table 1.

  As is clear from Table 1, the antireflection film of the present invention has a low reflection property by providing a plurality of layers composed of a specific inorganic substance and controlling the optical film thickness of each layer to a specific value. However, the reflection hue is neutral. Further, as is clear from FIG. 2, the antireflection film of the present invention has excellent reflection characteristics in a wide band (specifically, the maximum value of reflectance in the wavelength range of 420 nm to 660 nm is 1.5% or less). Have.

  INDUSTRIAL APPLICABILITY The antireflection film of the present invention can be suitably used for preventing reflection of external light in image display devices such as CRTs, liquid crystal display devices, and plasma display panels.

10 Transparent Substrate 20 Adhesion Layer 30 First Nb ₂ O ₅ Layer 40 First SiO ₂ Layer 50 Second Nb ₂ O ₅ Layer 60 Second SiO ₂ Layer 70 Antifouling Layer 100 Antireflection Film

Claims (7)

A transparent substrate, in order from the transparent substrate, and the adhesion layer, a first _Nb 2 _{O 5} layer, a first SiO ₂ layer and the second, a second _Nb 2 _{O 5} layer, a second It has a SiO ₂ layer and an antifouling layer in this order,
The optical thickness of the first Nb ₂ O ₅ layer is 28 nm to 33 nm,
The optical thickness of the first SiO ₂ layer is 43 nm to 57 nm,
The optical thickness of the second Nb ₂ O ₅ layer is 264 nm to 288 nm,
The optical thickness of the second SiO ₂ layer is 113 nm to 129 nm,
Anti-reflection film.   The antireflection film according to claim 1, wherein the antifouling layer has a refractive index of 1.00 to 1.50.   The antireflection film according to claim 1, wherein the antifouling layer has a thickness of 3 nm to 15 nm.   The antireflection film according to any one of claims 1 to 3, wherein a maximum value of reflectance in a wavelength range of 420 nm to 660 nm is 0.5% or less.   The antireflection film according to claim 1, wherein the transparent substrate includes a hard coat layer.   The antireflection film according to claim 1, further comprising an optical film on a surface of the transparent substrate opposite to the adhesive layer. An image display device comprising the antireflection film according to claim 1.