JP2001337202A - Antireflection film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antireflection film which is obtained by disposing an antireflection layer comprising two or more layers different from each other in refractive index (in particular high, medium and low refractive index layers) on at least one face of a transparent film substrate by the combination of a wet process and a vapor phase process, can control reflectance in a wide wavelength range, can be produced at a low cost and is excellent particularly in the adhesion of each layer exhibiting antireflection performance. SOLUTION: The antireflection film is obtained by disposing an antireflection layer including high and low refractive index layers on at least one face of a transparent film substrate. At least one high refractive index layer is a high refractive index layer formed by a vapor phase process, at least one low refractive index layer is a silicon dioxide film formed by coating with a sol prepared by hydrolyzing an organosilicon compound and the visible light reflectance of the antireflection layer is <=1%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-reflection film, and more particularly, to an anti-reflection film which has excellent adhesion to layers constituting an anti-reflection layer, suppresses light reflection in a wider wavelength range, and can be manufactured at low cost. The present invention relates to an antireflection film useful for

[0002]

2. Description of the Related Art Many displays are used in environments where external light enters, both indoors and outdoors. External light that has entered the display is specularly reflected in the display, and reproduces a virtual image of the external light on the display screen of the display.
For this reason, an image due to external light, for example, a fluorescent lamp or the like is reflected on the screen, causing a problem that an original display image is difficult to see. In addition, the external light incident on the display is mixed with the original display light to lower the display quality of the display.

[0003] Conventionally, in order to prevent such external light from entering the display, an antireflection film is stuck on the outer surface of the display. Examples of the antireflection film include a transparent plastic film substrate (film substrate) having an antireflection layer formed by laminating a high-refractive index layer and a low-refractive index layer made of a metal oxide or the like on the surface, or a film substrate. It is known that a low refractive index layer such as an inorganic compound or an organic fluorine compound is laminated as a single layer as an antireflection layer on the surface. Apart from these, there is also a method in which a coating layer containing transparent fine particles is formed on the surface of a film substrate to make the surface uneven, thereby irregularly reflecting external light to obtain a similar effect.

[0004]

By the way, in recent years, with the office automation (OA) in offices, the frequency of using a computer has been increased, and the length of time the computer has been used has been opposed to a CRT or a liquid crystal display. For this reason, it is feared that the display quality of the display is deteriorated due to an external light reflection image or the like, causing health problems such as eye fatigue, and an anti-reflection effect having a higher anti-reflection effect over a wide range of visible light than before. There is an increasing demand for films and optical materials having such antireflection films.

[0005] Furthermore, with the spread of outdoor life, the chances of using a television or a liquid crystal display outdoors are increasing more and more. In order to further improve the display quality of such a display and to allow a displayed image to be clearly recognized, There has been a demand for an antireflection film having a higher antireflection effect over a wide range of visible light, and an optical material provided with such an antireflection film.

However, a conventional antireflection film formed of a single layer of a low refractive index material of an inorganic compound or an organic compound exhibits a U-shaped spectral reflection characteristic and cannot obtain a high antireflection effect over a wide range of visible light. . In addition, a multilayer anti-reflection layer formed by alternately laminating high-refractive-index layers and low-refractive-index layers has an effective anti-reflection effect over a wide range of visible light, but the material used is expensive. Have the problem of raising costs.

In the case of a multilayer antireflection film (layer) formed only by wet coating, a metal oxide coating layer is usually used for the high refractive index layer, and this layer is in contact with another layer. Depending on the type, the adhesiveness may be poor due to the difference in wettability, and there is a problem that an additive for improving the adhesiveness is required, and that the selection of other layers is greatly restricted.

An object of the present invention is to solve the above problems at the same time, to achieve excellent adhesion of each layer constituting the antireflection layer, to suppress light reflection in a wider wavelength range, and to manufacture the display at low cost. Another object of the present invention is to provide an anti-reflection film useful for:

[0009]

SUMMARY OF THE INVENTION According to the present invention, there is provided an antireflection method comprising providing a transparent film substrate with an antireflection layer including a high refractive index layer and a low refractive index layer on at least one surface thereof. A film, wherein at least one layer of the high refractive index layer is a high refractive index layer formed by a gas phase method, and at least one layer of the low refractive index layer is a sol obtained by hydrolysis of an organosilicon compound. This is achieved by an antireflection film, which is a silicon oxide film formed by coating, and the antireflection layer has a visible light reflectance of 1% or less.

In a preferred embodiment, the antireflection layer has a three-layer structure in which a medium refractive index layer, a high refractive index layer, and a low refractive index layer are sequentially laminated on a transparent film substrate. The refractive index layer is formed by a vapor phase method, and the middle refractive index layer and the low refractive index layer are formed by a wet method, and the vapor phase method of forming the high refractive index layer is a sputtering method. That the high refractive index layer is made of titanium oxide, zirconium oxide, tin oxide, indium tin oxide, zinc oxide, cerium oxide, niobium oxide, yttrium oxide, tantalum oxide or a mixture of two or more thereof, and the transparent film It includes that a hard coat layer is formed between the base material and the antireflection layer, and that a water repellent / antifouling layer is formed on the antireflection layer.

Further, the present invention includes an optical material having the antireflection film.

The polymer constituting the transparent film substrate in the present invention includes polyester (eg, polyethylene terephthalate (PET), polyethylene naphthalate, etc.), poly (meth) acrylic (eg, polymethyl methacrylate (PMMA), etc.), Examples thereof include polycarbonate (PC), polystyrene, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyethylene, ethylene-vinyl acetate copolymer, polyurethane, triacetate, and cellophane. Of these, PET, PC and PMMA are preferred.

The transparent film substrate may be a non-stretched film or a stretched film depending on the type of the polymer. For example, a polyester film such as PET
The film is usually a biaxially stretched film,
Films, triacetate films, cellophane films and the like are usually unstretched films.

The thickness of the transparent film substrate is appropriately determined depending on the use of the antireflection film, but is usually 1 μm to 1 μm.
0 mm.

The antireflection layer according to the present invention is provided on at least one surface of the transparent film substrate. The antireflection layer includes at least a high-refractive-index layer and a low-refractive-index layer. At least one of the high-refractive-index layers is formed by a gas phase method, and at least one of the low-refractive-index layers is formed. Is a silicon oxide film formed by applying a (silicon oxide) sol obtained by hydrolysis of silicon alkoxide, and the antireflection layer must have a visible light reflectance of 1% or less.

The anti-reflection layer is an anti-reflection layer utilizing the coherence of light, and each layer is nd = λ / 4 (where n is the refractive index of the layer, d is the layer thickness (nm), and λ is Light wavelength (n
m)). This antireflection layer is composed of two layers, a high refractive index layer and a low refractive index layer (outermost layer), or a high refractive index layer and a low refractive index layer are alternately laminated in three or more layers, and the low refractive index layer is Although a structure in which the outermost layer is formed may be used, it has a three-layer structure in which a medium refractive index layer, a high refractive index layer, and a low refractive index layer are sequentially laminated on a transparent film substrate, and the high refractive index layer is formed of a gas phase. It is preferable that the medium refractive index layer and the low refractive index layer are formed by a wet method. Here, the magnitude of the refractive index is a relative relationship between the magnitudes of the refractive indexes. For example, when a high refractive index layer and a low refractive index layer are formed, the refractive index (nH) of the high refractive index layer is 1. 6
The refractive index (nL) of the low refractive index layer is preferably 5 or more, and the refractive index (nL) of the low refractive index layer is preferably 1.5 or less. The refractive index (nH) exceeds 1.85, and the refractive index (nM) of the medium refractive index layer exceeds 1.5.
1.85, the refractive index (nL) of the low refractive index layer is preferably 1.5 or less.

The high refractive index layer in the present invention is preferably formed by a vapor phase method. In the wet method, it is difficult to form a layer having a high refractive index, and it is difficult to obtain a layer having good reflection characteristics. According to this vapor phase method, a layer having a high refractive index, which cannot be obtained by a wet method, can be formed, and it is also advantageous in terms of adhesion. In the case of the wet method, the adhesiveness of the high refractive index layer largely depends on the wettability of another layer in contact with the high refractive index layer. For example, it is difficult to form an inorganic layer (high refractive index layer) on an organic resin layer, In the case of the vapor phase method, an anchoring effect is obtained at the time of forming the layer, so that high adhesion can be exhibited regardless of the wettability of the substrate. In the case where a silicon oxide film of a low refractive index layer is formed over a high refractive index layer, the silicon oxide film has a high affinity with an inorganic layer (high refractive index layer) formed by a gas phase method and has a high affinity. Shows adhesion.

As the vapor phase method, a vacuum film forming process such as a vacuum evaporation method, a reactive evaporation method, an ion beam assisted evaporation method, a sputtering method, an ion plating method, and a plasma CVD method can be used. The sputtering method is preferred from the viewpoint of properties.

As a material for forming the high refractive index layer,
Titanium oxide, zirconium oxide, tin oxide, indium
It is preferable to use tin oxide, zinc oxide, cerium oxide, niobium oxide, yttrium oxide, tantalum oxide, or a mixture of two or more of these.

The low refractive index layer in the present invention is formed by a wet method, and at least one of the constituent layers is formed by coating a (silicon oxide) sol obtained by hydrolysis of an organic silicon compound. It is a silicon film (layer).

Materials for forming the low refractive index layer include:
A sol obtained by hydrolyzing an organic silicon compound, particularly a silicon alkoxide containing tetraalkoxysilane, is used. This sol can be prepared by dissolving an organosilicon compound in an organic solvent suitable for coating and hydrolyzing with a certain amount of water.

[0022] Preferred examples of the organic silicon compound used in the formation of the sol, the general formula R _a ¹ R _b ² a compound represented by SiX _{4- (a + b)} can be preferably exemplified. Here, R ¹ and R ² are an alkyl group, an alkenyl group, an allyl group, or a hydrocarbon group having a halogen group, an epoxy group, an amino group, a mercapto group, a methacryl group or a cyano group,
X is a hydrolyzable group selected from an alkoxyl group, an alkoxyalkoxyl group, and a halogen or acyloxy group, and a and b are each 0, 1, or 2,
+ B is 2 or less.

Specific examples of the organosilicon compound include tetramethoxysilane, tetraethoxysilane, tetran
Tetraalkoxide silanes such as -propoxysilane, tetra i-propoxysilane, tetra n-butoxysilane, tetrasec-butoxysilane, tetrat-butoxysilane; methyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxyethoxysilane, Methyltriacetoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane,
Ethyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ -Chloropropyltriethoxysilane, γ-chloropropyltriacetoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ- Mercaptopropyltriethoxysilane,
N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, β-cyanoethyltriethoxysilane, methyltriphenoxysilane, chloromethyltrimethoxysilane, chloromethyltriethoxysilane, glycidoxymethyltrimethoxysilane, Sidoxymethyltriethoxysilane, α-glycidoxyethyltrimethoxysilane, α-glycidoxyethyltriethoxysilane, β-
Glycidoxyethyltrimethoxysilane, β-glycidoxyethyltriethoxysilane, α-glycidoxypropyltrimethoxysilane, α-glycidoxypropyltriethoxysilane, β-glycidoxypropyltrimethoxysilane, β- Glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane,
γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltripropoxysilane, γ-glycidoxypropyltributoxysilane, γ-glycidoxypropyltrimethoxyethoxysilane, γ-glycidoxypropyltriphenoxysilane , Α-glycidoxybutyltrimethoxysilane, α-glycidoxybutyltriethoxysilane, β-glycidoxybutyltrimethoxysilane, β-glycidoxybutyltriethoxysilane, γ-
Glycidoxybutyltrimethoxysilane, γ-glycidoxybutyltriethoxysilane, δ-glycidoxybutyltrimethoxysilane, δ-glycidoxybutyltriethoxysilane, (3,4-epoxycyclohexyl) methyltrimethoxysilane , (3,4-epoxycyclohexyl)
Methyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, β-
(3,4-epoxycyclohexyl) ethyltripropoxysilane, β- (3,4-epoxycyclohexyl) ethyltributoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxyethoxysilane, γ- (3,4 -Epoxycyclohexyl) propyltrimethoxysilane,
β- (3,4-epoxycyclohexyl) ethyltriphenoxysilane, γ- (3,4-epoxycyclohexyl) propyltrimethoxysilane, γ- (3,4-epoxycyclohexyl) propyltriethoxysilane, δ- (3, 4-epoxycyclohexyl) butyltrimethoxysilane, δ-
Trialkoxysilanes such as (3,4-epoxycyclohexyl) butyltrimethoxysilane, trialcyloxysilane, triphenoxysilanes; dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldiethoxysilane, γ-
Chloropropylmethyldimethoxysilane, γ-chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercapto Propylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, glycidoxymethylmethyldimethoxysilane, glycidoxymethylmethyldiethoxysilane Α-glycidoxyethylmethyldimethoxysilane, α-glycidoxyethylmethyldiethoxysilane, β-glycidoxyethylmethyldimethoxysilane, β-glycidoxy -Methyldiethoxysilane, α-glycidoxypropylmethyldimethoxysilane, α-glycidoxypropylmethyldiethoxysilane, β-glycidoxypropylmethyldimethoxysilane, β-glycidoxypropylmethyldiethoxysilane, γ- Glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldipropoxysilane, γ-glycidoxypropylmethyldibutoxyethoxysilane, γ-glycidoxypropylmethyldimethoxy Ethoxysilane, γ-glycidoxypropylmethyldiphenoxysilane, γ-glycidoxypropylmethyldiacetoxysilane, γ-glycidoxypropylethyldimethoxysilane, γ-glycidoxypropylethyldiethoxysilane, γ-glycidoxypro Dialkoxysilanes, diphenoxysilanes, diacyloxysilanes such as ruvinyldimethoxysilane, γ-glycidoxypropylvinyldiethoxysilane, γ-glycidoxypropylphenyldimethoxysilane, γ-glycidoxypropylphenyldiethoxysilane And the like. Two or more of these organic silicon compounds can be used. In particular, the use of an organosilicon compound containing an epoxy group or a glycidoxy group is suitable for the purpose of suppressing the occurrence of cracks and imparting dyeing properties, and is of high added value.

The hydrolysis of the organic silicon compound is preferably carried out by dissolving the organic silicon compound in a suitable solvent. As the solvent used, for example, methyl ethyl ketone, isopropyl alcohol, methanol, ethanol, methyl isobutyl ketone, ethyl acetate, alcohols such as ethyl acetate, ketones, esters, halogenated hydrocarbons, toluene, aromatic hydrocarbons such as xylene, And mixtures thereof. The organic silicon compound is dissolved in the solvent so as to be 0.1% by weight or more, preferably 0.1 to 10% by weight in terms of SiO _2, which is generated as a result of 100% hydrolysis and condensation of the silicon compound. If the concentration of the (silicon oxide) sol is less than 0.1% by weight, the sol film to be formed cannot sufficiently exhibit desired characteristics.
If it exceeds 0% by weight, it becomes difficult to form a transparent homogeneous film.
In the present invention, an organic or inorganic binder can be used in combination as long as the solid content is within the above-mentioned range.

For the hydrolysis of the organosilicon compound, water is added to the above solution in an amount not less than the amount required for the hydrolysis, and at a temperature of 15 to 35 ° C., preferably 22 to 28 ° C., for 0.5 to 48 hours, preferably It is preferable to carry out by stirring for 2 to 24 hours. Further, it is preferable to use a catalyst for the hydrolysis. As these catalysts, acids such as hydrochloric acid, nitric acid, sulfuric acid and acetic acid are preferable, and these acids are preferably added so that the pH of the whole solution becomes 1 to 6. The (silicon oxide) sol thus obtained is colorless and transparent, is a stable liquid having a pot life of about one month, has good wettability to the film substrate, and is excellent in application suitability.

The (silicon oxide) sol obtained by hydrolysis of the organosilicon compound is in a liquid state and has a viscosity within a range applicable to ordinary coating operations.
It is preferably 0 poise or less, more preferably 1 poise or less. A liquid having a higher viscosity makes it difficult to form a uniform coating film. As a coating method, a method used in a usual coating operation can be used. For example, a spin coating method, a dip method, a spray method, a roll coater method, a meniscus coater method, a flexographic printing method, a screen printing method, a beat coater method And a microgravure coater method. After application, the coating is dried to form a low refractive index layer. The drying temperature (heat treatment temperature) is 60 to 150 ° C, and more preferably 80 to 11
0 ° C. is preferred.

In the present invention, when the low refractive index layer is composed of two or more layers, at least one layer is composed of the above-mentioned silicon oxide film. An organic material and / or an inorganic material that form a film having a lower refractive index than the refractive index layer can be used. This material will be described as a material for forming a medium refractive index layer described later, and in addition to the examples, a vinyl-based copolymer containing an aromatic group not containing an aromatic ring, various fluorine-substituted polymers, and an aromatic group It is composed of a polyester (including alkyd) copolymer containing no ring, a cellulose derivative, a silicone polymer, a hydrocarbon polymer, a prepolymer thereof, or a product obtained by adding a curable functional group thereto, and a curing agent. A composition etc. can be illustrated. In this case, the layer is preferably formed according to the method for forming the middle refractive index layer.

The medium refractive index layer in the present invention is preferably formed by a wet method. As the liquid material used for forming the medium refractive index layer, in addition to the case where only the film forming substance is used, those containing various volatile solvents in order to impart necessary coating workability can be used. Here, the liquid material has a viscosity within a range in which a normal coating operation can be applied.
Poise or less is preferred. A liquid having a higher viscosity makes it difficult to form a uniform coating film. As a coating method, a method used in a usual coating operation can be used. For example, a spin coating method, a dip method, a spray method, a roll coater method, a meniscus coater method, a flexographic printing method, a screen printing method, a beat coater method And a microgravure coater method. After application, the coating film is dried to form a medium refractive index layer. The drying temperature is preferably from 120 to 180C, more preferably from 130 to 160C. When the layer forming material contains a thermosetting material, it is preferable to select the drying temperature from the temperature at which the thermosetting reaction is performed efficiently.

The film-forming substance is a substance in which a thin film to be formed satisfies the requirement of a medium refractive index and which forms a liquid by itself or by dispersing or dissolving it in a solvent. Either organic or inorganic may be used. For example, fine particles of a degree that does not impair the transparency, in particular, inorganic fine particles may be dispersed, organic materials or film-forming inorganic materials that can be dispersed or dissolved in a solvent, or those that are themselves liquid, Alternatively, a mixture of such an inorganic material and an organic material can be used.

When these materials are used for the medium refractive index layer,
As the organic material, a film-forming substance having a relatively high refractive index, for example, polystyrene, a polystyrene copolymer,
Polycarbonate, other thermoplastic polymers (for example, a polymer having an aromatic ring, a heterocyclic ring or an aliphatic ring which may have a halogen substituent other than fluorine, or an S, N, or P atom in a polymer linear chain) , A melamine resin, a phenolic resin, an epoxy resin, a curable resin using a curing agent (eg, an epoxy compound), a polyurethane formed from an isocyanate (eg, an alicyclic isocyanate, an aromatic isocyanate, etc.) and a polyol. A modified resin (or prepolymer) having radical curability imparted by introducing a double bond into the composition, the above compound or polymer can be preferably used.

When the organic material is used by dispersing fine particles, particularly inorganic fine particles therein, the inorganic fine particles generally have a high refractive index, and therefore have a lower refractive index than when the organic material is used alone. It is preferable to adjust the refractive index of the layer by using the materials shown. In addition to the organic materials described above, vinyl polymers including acrylics, cellulose polymers, urethane polymers, and mixtures of these and various curing agents, resins having a curable functional group, and the like, An organic material having transparency and capable of stably dispersing inorganic fine particles can be used.

The inorganic material is a film-forming, dispersible in a solvent, or a liquid itself, and contains various elements (eg, silicon, titanium, aluminum,
Alkoxides, organic acid salts, and coordination compounds.

[0033] As the silicon compounds have the general formula R _a ¹ R _b ² Si
A compound represented by X _{4- (a + b)} or a hydrolysis product thereof can be preferably exemplified. Here, R ¹ and R ² are each an alkyl group, an alkenyl group, an allyl group, or a hydrocarbon group having a halogen group, an epoxy group, an amino group, a mercapto group, a methacryl group or a cyano group, and X is an alkoxyl group. A hydrolyzable group selected from an alkoxyalkoxyl group and a halogen or acyloxy group, wherein a and b are each 0, 1 or 2, but a + b is 2 or less.

Specific examples of the silicon compound include the same compounds as those used for forming the low refractive index layer.

These are sols formed by hydrolysis, for example,
It is preferably used as fine particle silica, particularly silica sol dispersed in a colloidal state, and can adjust the refractive index and improve the adhesion.

Preferred examples of the compound other than the silicon compound include titanium tetraoxide, titanium tetra-i
-Propoxide, titanium tetra-n-propoxide, titanium tetra-n-butoxy, titanium tetra-sec-butoxy, titanium tetra-tert-butoxide, aluminum triethoxide, aluminum-i-propoxide, aluminum tributoxide, antimony Triethoxide, antimony tributoxide, zirconium tetraethoxide, zirconium tetra-i-propoxide, zirconium tetra-n-propoxide, zirconium tetra-n-butoxide, zirconium tetra-s
metal alcoholate compounds such as ec-butoxide, zirconium tetra-tect-butoxy, di-isopropoxytitanium bisacetylacetonate, diptoxytitanium bisacetylacetonate, diethoxytitanium bisacetonate, diacetylacetone zirconium, aluminum acetylacetonate Chelating compounds such as aluminum acetylacetonate, aluminum di-n-butoxymonoethylacetonate, aluminum di-i-propoxide monomethylacetoacetate, and tri-n-butoxide zirconium monoacetylacetate; furthermore, zirconium ammonium carbonate or zirconium And the like. Among these compounds, those having hydrolyzability can be used after being hydrolyzed.

As the compound constituting the inorganic fine particles, for example, aluminum, titanium, zirconium,
Oxides of metal elements such as antimony and tin are preferably used. These are fine particles, powder or water and / or
Or it can be obtained as a colloidal dispersion in another solvent. These are mixed and dispersed in the above-mentioned organic material, particularly in the silicon compound. The average particle size of the inorganic fine particles is preferably from 0.03 to 0.06 μm.

As described above, the antireflection film of the present invention has an antireflection layer formed on at least one surface of a transparent film substrate. More preferably, the antireflection film has a structure as shown in FIG. A hard coat layer is provided on a transparent film substrate, and an antireflection layer consisting of a middle refractive index layer, a high refractive index layer, and a low refractive index layer is provided thereon. It is preferable that it has a structure provided with a layer.

FIG. 1 is a diagram schematically showing a cross section of an antireflection film according to a preferred embodiment of the present invention. In FIG. 1, 1 is a transparent substrate film, 2 is a hard coat layer,
3 is a medium refractive index layer, 4 is a high refractive index layer, 5 is a low refractive index layer, 6
Is a water repellent / antifouling layer. The antireflection layer 7 is a medium refractive index layer 3,
It comprises three layers, a high refractive index layer 4 and a low refractive index layer 5. In the present invention, the configuration other than the antireflection layer 7 formed by a specific method can be the same configuration as a known antireflection film.

The hard coat layer 2 is provided as necessary in order to impart a desired hardness to the antireflection film. As the hard coat layer 2, it is preferable to form a layer having transparency and appropriate hardness. The forming material is not particularly limited, and for example, a curable resin or a thermosetting resin by irradiation with ionizing radiation or ultraviolet rays can be used. In particular, ultraviolet irradiation-curable acrylic or organic silicon resins and thermosetting polysiloxane resins are preferred. Known resins can be used as these resins. further,
It is more preferable that the refractive index of the hard coat layer 2 is equal to or close to that of the transparent film substrate 1. However, when the film thickness is 3 μm or more, this point is not particularly necessary.

In forming the hard coat layer 2, the coating method is not limited, but it is preferable to form the hard coat layer 2 with a smooth and uniform surface.

In the hard coat layer 2, transparent inorganic or organic fine particles having an average particle diameter of 0.01 to 3 μm may be mixed and dispersed. As a result, a process of light diffusion and dwelling called anti-glare can be performed. By forming the anti-reflection layer 7 on the hard coat layer 2 which has been subjected to the light diffusing treatment, the blur of the image is reduced, and the image becomes clearer than when the light diffusing treatment is simply performed. Become. The fine particles are not particularly limited as long as they are transparent, but fine particles made of a low refractive index material having a refractive index of 1.6 or less are preferable. For example, silicon oxide particles, magnesium fluoride particles and the like are stable and heat resistant. It is preferable from the viewpoint of the above.

The water-repellent / stain-resistant layer 6 is formed on the anti-reflection layer 7 for protecting the surface of the anti-reflection layer 7 and further improving the stain resistance. Any material can be used without limitation as long as it has transparency and the required performance is satisfied. For example, a compound having a hydrophobic group, more specifically, a fluorocarbon, perfluorosilane, or the like, or a high molecular compound thereof can be preferably used. In addition, a polymer compound having oil repellency such as a methyl group is suitable for improving fingerprint wiping stains.

The method for forming the water-repellent / antifouling layer 6 is as follows.
Vacuum evaporation method according to the forming material. Sputtering method,
Ion plating method. Vacuum film forming processes such as plasma CVD and plasma polymerization, microgravure,
Various coating methods of a wet process such as a screen and a dip can be used.

The thickness of the water-repellent / dirt-proof layer 6 is determined by the thickness of the anti-reflection layer 7
It is necessary to set so as not to impair the function described above, and it is usually preferable that the shape film thickness is 50 nm or less.

The anti-reflection film of the present invention can be used in the same manner as a conventional anti-reflection film. For example, it is bonded to a glass plate, a plastic plate, a polarizing plate or the like using an adhesive or an adhesive. An optical member having antireflection properties can be obtained. Therefore, the present invention also covers such optical materials.

[0047]

Next, the present invention will be described in more detail with reference to embodiments. In addition, the film property was evaluated by the following method.

1. Adhesion of layer The film on which the layer was formed was cut with 6 cutters in each of vertical and horizontal directions at 2 mm intervals with a cutter knife to make 25 grids, and a Nichiban cello tape was attached on the grid, and the cello tape was turned at 90 degrees. The film is peeled at a peeling angle, and the number of remaining crosses is visually evaluated for the thin film on the film. ：: 25 remaining Δ: 20 to 24 ×: 19 or less

2. Visible Light Reflectance Using a UV-3101PC manufactured by Shimadzu Corporation, irradiating the antireflection layer side of the antireflection film, measuring in the following wavelength range, and calculating the integrated visible light reflectance based on JIS A5759.

Example 1 A biaxially oriented PET film (188 μm in thickness) was used as the transparent film substrate 1, and a UV-curable hard coating agent (JSR Desolite Z7500) was formed on one side to a thickness of about 2 μm. To form a hard coat layer, and then apply a solution of tetrabutyl titanate in ligroin: n-butanol = 3: 1 by microgravure coating on the hard coat layer. Dry for 2 minutes, nd = λ / 4
(Λ = 550 nm, n = refractive index of layer 1.78, d = layer thickness
77 (nm)). Further, a TiO ₂ layer as a high refractive index layer is further formed thereon by sputtering, and nd = λ / 4 (λ = 550 nm, n = refractive index of the layer 2.
0, d = layer thickness 69 (nm)), and a SiO ₂ sol obtained by hydrolyzing tetraethylsilane on the SiO ₂ layer is coated thereon and dried, and then nd = λ / 4
(Λ = 550 nm, n = refractive index of layer 1.45, d = layer thickness
The film was dried at 100 ° C. for 1 minute so as to have a thickness of 95 (nm). Finally, a fluorine-based surfactant was applied thereon as a stain- and water-repellent layer to a thickness of 2 nm to obtain an antireflection film.

The spectral reflection characteristics of the antireflection film by absolute reflection measurement and the adhesion of each layer were evaluated. Table 1 shows the results.

[Comparative Example 1] Example 1 except that the high refractive index layer was formed by applying an agent obtained by dispersing TiO ₂ fine particles (Ishihara Sangyo ET300W) in a binder of an acrylic resin (Mitsubishi Rayon Dianal LR637). Went the same as.

The spectral reflection characteristics of the obtained antireflection film by absolute reflection measurement and the adhesion of each layer were evaluated. Table 1 shows the results.

[0054]

[Table 1]

[0055]

According to the present invention, an antireflection layer composed of two or more layers having different refractive indexes is laminated on at least one surface of a transparent film substrate by a combination of a wet method and a gas phase method. It is possible to provide an antireflection film which can suppress the reflectance in the region and can be manufactured at a low cost, and in particular, has excellent adhesion of each layer exhibiting antireflection performance.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a cross section of an antireflection film showing one embodiment of the present invention.

[Explanation of symbols]

 1: transparent substrate 2: hard coat layer 3: medium refractive index layer 4: high refractive index layer 5: low refractive index layer 6: antifouling / water repellent layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) G09F 9/00 313 G02B 1/10 Z F term (reference) 2K009 AA05 AA06 AA15 CC03 CC42 DD02 DD04 EE05 4F100 AA17B AA17D AA20C AA20E AA21B AA21D AA25B AA25D AA27B AA27D AA28B AA28D AA33B AA33D AH06C AH06E AH06K AK42A AR00A AR00B AR00C AR00D AR00E BA05 BA06 BA07 BA10C BA10E BA13 EH66B EH66D EJ38A GB41 JB06E JB14E JK06 JK12E JL06E JN01 JN01A JN06 JN18B JN18C JN18D JN18E YY00 4K029 AA11 AA25 BA02 BA03 BA15 BA16 BA17 BA43 BA45 BA47 BA48 BA49 BB02 BC07 CA05 5G435 AA01 FF01 KK07

Claims (9)

[Claims] 1. An anti-reflection film comprising an anti-reflection layer including a high-refractive index layer and a low-refractive index layer provided on at least one surface of a transparent film substrate, wherein at least one of the high-refractive index layers is A high refractive index layer formed by a gas phase method, at least one of the low refractive index layers is a silicon oxide film formed by applying a sol obtained by hydrolysis of an organosilicon compound, and The visible light reflectance of the antireflection layer is 1
% Or less. 2. An organic compound represented by the following general formula: R _a ¹ R _b ² SiX _{4- (a + b)} (where R ¹ and R ² are an alkyl group, an alkenyl group, an allyl group or a halogen group, X is a hydrocarbon group having an epoxy group, an amino group, a mercapto group, a methacryl group or a cyano group, and X is a hydrolyzable group selected from an alkoxyl group, an alkoxyalkoxyl group, and a halogen or an acyloxy group; Is 0, 1 or 2, respectively, and a + b is 2 or less.) The antireflection film according to claim 1, wherein 3. The antireflection film according to claim 1, wherein the organosilicon compound is tetraalkoxysilane. 4. The antireflection layer has a three-layer structure in which a medium refractive index layer, a high refractive index layer, and a low refractive index layer are sequentially laminated on a film substrate, and the high refractive index layer is formed by a gas phase method. The antireflection film according to claim 1, wherein the antireflection film according to claim 1, wherein the medium refractive index layer and the low refractive index layer are formed by a wet method. 5. The antireflection film according to claim 1, wherein the vapor phase method for forming the high refractive index layer is a sputtering method. 6. The high refractive index layer is made of titanium oxide, zirconium oxide, tin oxide, indium tin oxide, zinc oxide, cerium oxide, niobium oxide, yttrium oxide, tantalum oxide or a mixture of two or more thereof. , 4-5
The antireflection film according to any one of the above. 7. The anti-reflection film according to claim 1, wherein a hard coat layer is formed between the transparent film substrate and the anti-reflection layer. 8. The anti-reflection film according to claim 1, wherein a water-repellent / anti-fouling layer is formed on the anti-reflection layer. 9. An optical material having the antireflection film according to claim 1.