JPH10319211A - Antireflection film and image display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily produce an antireflection film having a high antireflection effect and superior scratch resistance by using a low refractive index layer composed of fluorine-contg. polymer particles and a polymerizable monomer and/or a polymerizable oligomer and/or a polymerizable polymer. SOLUTION: This antireflection film contains a low refractive index layer 1 obtd. by piling up two or more fine particles 2 of a fluorine-contg. polymer (fluororesin) having 5-200 nm average particle diameter on a substrate 11 and forming microvoids among the fine particles. The low refractive index layer 1 is composed of the fluorine-contg. polymer particles 2 and a polymerizable monomer and/or a polymerizable oligomer and/or a polymerizable polymer. The layer 1 is preferably used in combination with a high refractive index layer 4 formed on the substrate 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display (L).
The present invention relates to an antireflection film effective for lowering the reflectance of an image display surface of an image display device such as a CD) and an image display device having an antireflection film.

[0002]

2. Description of the Related Art Hitherto, as an antireflection film for light having a wide wavelength range such as visible light, a multilayer film formed by laminating transparent thin films of a metal compound such as a metal oxide has been used. When a single-layer film having a low refractive index is used instead of a multilayer film as an antireflection film, it is effective for monochromatic light, but a single-layer film is effective for light having a wide wavelength range to some extent. Does not show a protective effect. In the above-described multilayer film, the more the number of layers, the more effective the antireflection film for light having a wider wavelength range. Therefore, as the conventional antireflection film, a film obtained by laminating three or more layers of metal oxide or the like by means such as physical or chemical vapor deposition has been used. However, in order to form an antireflection film having a multilayer structure, physical vapor deposition whose thickness is controlled with high precision in accordance with the relationship between the refractive index and the film thickness of each layer that is optimally designed in advance is performed by the number of layers. It must be done, is cumbersome and very expensive. Further, in order to improve the anti-contamination property such as scratch resistance or fingerprint adhesion of the surface, it is necessary to newly provide a layer made of a fluorine-containing resin, for example.

In addition to the above-described method using a multilayer film, a method for obtaining an antireflection effect by a film whose refractive index gradually changes in the film thickness direction from the interface with air is known. For example, JP-A-2-245702 discloses that an ultrafine particle of SiO ₂ having an intermediate refractive index between a glass substrate and MgF ₂ and an ultra fine particle of MgF ₂ are mixed and applied to a glass substrate, and then applied from the glass substrate surface. SiO gradually toward the film surface
By decreasing the mixing ratio of ₂ to increase the mixing ratio of MgF _2, with greatly changes in the refractive index of the coating layer, the coating layer and the air, and the refractive index change at the interface between the coating layer and the glass substrate It is described that an anti-reflection effect can be obtained by making it gentle. The thus formed anti-reflection film exhibits a high anti-reflection effect because the change in the refractive index between the bottom surface and the glass surface is small.

[0004] Also, Japanese Patent Application Laid-Open No. 5-13021 discloses that
An antireflection film comprising two layers using ultrafine particles having MgF ₂ and SiO ₂ dispersed in ethyl silicate is disclosed. For example, the first layer is composed of 7 MgF ₂ / SiO _2.
The second layer is a layer in which MgF ₂ / SiO ₂ is 1/1, the refractive index of the first layer is 1.42, and the refractive index of the second layer is 1.44. Therefore, the change in the refractive index cannot be said to be large, and a sufficient antireflection effect cannot be obtained.

[0005] Japanese Patent Application Laid-Open No. 7-92305 discloses that
Refractive index of 1.428 consisting of core and surrounding shell
An anti-reflection film is disclosed which comprises an upper layer portion (low refractive index) having irregularities on the surface formed of air and fine particles and a lower layer portion formed only of fine particles.
And the core of the ultrafine particles is methyl methacrylate, methacrylic acid, trifluoroethyl acrylate,
Formed from N-isobutoxymethylacrylamide,
The shell part is formed from styrene, acrylic acid, and butyl acrylate.

Further, Japanese Patent Application Laid-Open No. Hei 7-168006 discloses that the surface formed of air and fine particles (eg, MgF ₂ ) has an irregular upper layer portion (low refractive index) and a fine particle only middle layer portion (medium refractive index). ), And an antireflection film comprising fine particles and a lower layer portion formed of a binder.

[0007] However, the above-mentioned Japanese Patent Application Laid-Open No. Hei 2-2457.
02, JP-A-5-13021, JP-A-7-
The antireflection films described in JP-A-92305 and JP-A-7-168006 utilize the principle that the refractive index to air gradually changes in the thickness direction. These antireflection films require complicated operations and skillful techniques for their preparation, and the obtained films do not have a satisfactory antireflection effect.

In view of this, Japanese Patent Application No. 8-344688 discloses a low refractive index layer in which microvoids are formed between fine particles by stacking at least two fine particles of a fluoropolymer having an average particle size in the range of 5 to 200 nm. By forming an antireflection film characterized by including at least one layer in the light interference layer on the surface of various displays, it is disclosed that an antireflection film having excellent antireflection performance can be obtained. The light interference layer has a problem that the scratch resistance is poor.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an antireflection film which can be easily formed and has a high antireflection effect and excellent scratch resistance. Another object of the present invention is to provide an image display device which can be easily formed and has an antireflection film exhibiting a high antireflection effect and excellent scratch resistance.

[0010]

According to the present invention, there is provided 1) a method in which at least two or more fine particles of a fluoropolymer having an average particle size in the range of 5 to 200 nm are stacked on a base material to form fine particles. An anti-reflection film comprising a low refractive index layer formed by forming microvoids in the antireflection film, wherein the low refractive index layer has fluorine-containing polymer particles, a polymerizable monomer and / or a polymerizable oligomer and / or An object of the present invention is to provide an antireflection film made of a polymer having polymerizability and having excellent scratch resistance and the like. Preferred embodiments of the antireflection film of the present invention are as follows. 2) The light interference layer is composed of a plurality of layers including at least one layer having a higher refractive index than any of the low refractive index layer and the base material, and each layer includes a common monomer and / or oligomer and / or polymer as a binder. Included as 3) A hard coat layer having a thickness of 0.5 to 10 microns is provided between the light interference layer and the substrate on which the light interference layer is provided. 4) An image display device having the antireflection film according to 1), 2) or 3).

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The antireflection film of the present invention comprises a low refractive index layer composed of the above-mentioned fluoropolymer fine particles and microvoids formed on a high refractive index layer having a higher refractive index. It is preferred that the layer be composed of layers. Further, it is preferable that these layers are provided on a support (preferably a transparent film). Further, in the antireflection film of the present invention, a low refractive index layer composed of the above-mentioned fluoropolymer fine particles and microvoids is formed on a high refractive index layer having a higher refractive index, and further a high refractive index layer is formed. And three layers formed on a middle refractive index layer having a lower refractive index and a higher refractive index than the low refractive index layer. Further, it is preferable that these layers are provided on a support (preferably a transparent film).

The present invention also provides an image display device having at least one of the above antireflection films.

The antireflection film of the present invention basically has a low refractive index composed of fine particles of a fluororesin (fluorine-containing polymer), a polymerizable monomer and / or a polymerizable oligomer and / or a polymerizable polymer. With layers. The low-refractive-index layer contains the fine particles at least 2 times.
Includes microvoids formed between particles by stacking more than one.

FIG. 1 shows a typical configuration example of the antireflection film of the present invention. Low refractive index layer 1, high refractive index layer 4, medium refractive index layer 7
The light interference layer and the hard coat layer 10 composed of the three layers described above are sequentially formed on a transparent film (support) 11.
The low-refractive-index layer is formed of fluorine resin fine particles 2 and microvoids formed between the fine particles. In the low-refractive-index layer, microvoids are formed between the fine particles by overlapping at least two fine particles of the fluororesin in the film thickness direction. Therefore, the microvoids are generally uniformly arranged in the low refractive index layer. The fluorine resin fine particles are generally melted or softened by removing or heating the solvent, and partially adhere to each other via the binder 3. Alternatively, when the fluororesin fine particles have a functional group (reactive group), the particles can be strongly bonded to each other by a reaction between the functional groups or between the functional group and the binder. Also, the fine particles of the fluororesin can be adhered to each other by using a very small amount of a silane coupling agent. Particularly in the present invention, a hard low refractive index film having excellent scratch resistance is obtained by including a very small amount of a binder composed of a polyfunctional monomer and / or oligomer and / or polymer. Here, the monomer generally refers to a starting material capable of forming a polymer by a polymerization reaction. In general, an oligomer refers to a polymer of monomers having a degree of polymerization of about 2 to 20, but here, a polymer having a low polymerizability obtained by introducing a polymerizable functional group into such a relatively low to medium molecular weight polymer. Oligomers include substances of medium to medium molecular weight. Polymers are higher in molecular weight than oligomers,
Refers to all substances having a molecular weight in the region where high polymerity is exhibited. In the present invention, it is preferable to use a polymerizable monomer or a polymerizable oligomer. In general, when the light interference layer is composed of multiple layers, a problem of adhesion between each light interference layer and between the light interference layer and the hard code layer occurs. However, in the antireflection film of the present invention, each light interference layer has Since it contains a binder of the same material selected from the above, a film having excellent interlayer adhesion is obtained.

The fine particles generally have a thickness of one particle and are arranged in a plane direction to form a particle layer, and a plurality of particle layers are stacked to form a low refractive index layer of the present invention. . For this reason, the microvoids formed between the particles have substantially the same particle size, and thus are usually formed uniformly in the size of the voids and at intervals between the voids. The low refractive index layer of the present invention is fine particles in a microscopic scale, but can be regarded as an optically uniform layer when viewed on the order of the wavelength of light.

The refractive index of the air on the surface of the low refractive index layer of the present invention is 1, and the refractive index of the fine particles of the fluororesin of the present invention is higher than the refractive index of air, generally 1.25 to 1.45. Between. The low refractive index layer of the present invention is located between the refractive index of the air layer and the refractive index of the fine particles themselves. Therefore, the refractive index of the low refractive index layer of the present invention can be made lower than the refractive index of the material by the volume fraction of microvoids by making the fluororesin fine particles smaller.
The average particle size of the fluorine resin fine particles is generally in the range of 5 to 200 nm, preferably 5 to 50 nm. The thickness of the low refractive index layer is generally in the range of 5 to 400 nm,
200 nm is preferred.

As an example of a multilayer antireflection film, in an antireflection film having two layers, a high refractive index layer and a low refractive index layer generally satisfy the following conditions (1) and (2), respectively. mλ / 4 × 0.7 <n1 d1 <mλ / 4 × 1.3 (1) nλ / 4 × 0.7 <n2 d2 <nλ / 4 × 1.3 (2) In the above equation, m is Positive integer (typically 1, 2, or 3)
Where n 1 represents the refractive index of the high refractive index layer, d 1 represents the layer thickness (nm) of the high refractive index layer, n represents a positive odd number (generally 1), and n 2 represents the low refractive index layer. Represents the refractive index, and d2 represents the layer thickness (nm) of the low refractive index layer.
The refractive index n1 of the high refractive index layer is generally at least 0.05 higher than the transparent film, and the refractive index n1 of the low refractive index layer is higher.
2 is generally at least 0.1% higher than the refractive index of the high refractive index layer.
Low and at least 0.05 lower than the transparent film. Further, the refractive index n1 of the high refractive index layer is generally 1.5 to 1.7.
In the range.

The above conditions (1) and (2) are well-known conditions, for example, as disclosed in Japanese Patent Application Laid-Open No. 59-5040.
No. 1 publication.

As another example of the multilayer antireflection film, in an antireflection film having three layers, the middle, high and low refractive index layers generally satisfy the following conditions (3) to (5), respectively. hλ / 4 × 0.7 <n3 d3 <hλ / 4 × 1.3 (3) kλ / 4 × 0.7 <n4 d4 <kλ / 4 × 1.3 (4) jλ / 4 × 0.7 < n5 d5 <jλ / 4 × 1.3 (5) In the above formula, h is a positive integer (generally 1, 2, or 3)
, N3 represents the refractive index of the medium refractive index layer, d3 represents the layer thickness (nm) of the medium refractive index layer, k represents a positive integer (generally 1, 2 or 3), and n4 represents the high refractive index. Represents the refractive index of the refractive index layer, d4 represents the layer thickness (nm) of the high refractive index layer, j represents a positive odd number (generally 1), n5 represents the refractive index of the low refractive index layer, and d5 represents the thickness (nm) of the low refractive index layer. The refractive index n3 of the medium refractive index layer is generally in the range of 1.5 to 1.7, and the refractive index n3 of the high refractive index layer is
4 is generally in the range of 1.7 to 2.2.

The average particle diameter of the fine particles of the fluororesin (fluoropolymer) used in the present invention is generally in the range of 5 to 200 nm, and is 5 to 50 nm. Such fine particles are obtained, for example, from a polymer latex. As the particle size of the fine particles increases, scattering on the film surface increases,
If it exceeds nm, film haze occurs, which is not preferable. The fluororesin used for the antireflection film of the present invention is crystalline,
Any amorphous material can be used. Until now, crystalline fluororesin could not be used as an optical material film to reduce light transmittance,
By using fine particles having a particle size sufficiently smaller than the wavelength of light, even those having crystallinity can be used as an antireflection film without reducing light transmittance. The fluororesin fine particles generally have a glass transition temperature (Tg) of room temperature or higher, and preferably 100 ° C or higher. Tg
When the temperature is lower than room temperature, the fine particles are excessively softened and easily deformed and fused, so that microvoids disappear and the refractive index increases. As the fluorine resin fine particles, fine particles of two or more kinds of fluorine resins having different Tg can be used. In this case, the difference in Tg is generally at least 5 ° C.
C. or higher is preferred.

The fluororesin fine particles of the polymer latex are
For example, a core portion containing a large amount of fluorine atoms and contributing to lowering the refractive index of the material, and a shell portion having a relatively low fluorine atom content may be used. For this reason, the shell part
The adhesion between the fine particles or between the fine particles and the lower layer can be improved. The surface of the shell may have a functional group such as an acryloyl group or an epoxy group.

The monomers forming the fluorine-containing polymer of the present invention include compounds represented by the following general formula.

[0023]

Embedded image

Wherein R ¹ represents a hydrogen atom, a methyl group or a fluorine atom, and p and n each represent a positive integer;

[0025]

Embedded image

(Where n is an integer)

[0027]

Embedded image

(Where x is an integer of 1 to 4) Examples of the fluororesin obtained from the above monomer are shown below.

[0029]

Embedded image

(Provided that l + m + n is 1 to 6;
Is an integer from 0 to 5, m is an integer from 1 to 4, n is an integer from 0 to 1, and R is F or CF _2.

[0031]

Embedded image

(Provided that o + p + q is 1 to 6,
o, p and q are each an integer of 0 to 5)

[0033]

Embedded image

(Where R ¹ and R ² are each F or CF ₃ )

[0035]

Embedded image

[0036]

Embedded image

(However, R ¹ represents a hydrogen atom, a methyl group, or a fluorine atom, and p and n each represent a positive integer.)

[0038]

Embedded image

The refractive index of the fluorine resin decreases almost linearly in proportion to the content of fluorine atoms, and the refractive index of the low refractive index layer further decreases as the content of microvoids increases. By increasing the content of both, the refractive index of the low refractive index layer can be sufficiently reduced. Therefore, the fluorine resin is generally used in an amount of 0.30 weight fraction or more (preferably, 0.3% by weight).
0 to 0.75 weight fraction, especially 0.35 to 0.75 weight fraction), and the low refractive index layer is
~ 0.50 volume fraction microvoids, and
A volume fraction of 10 to 0.50 is preferable, especially 0.10 to
A 0.28 volume fraction is preferred.

When fine particles having a monodispersed particle size are closest packed, voids (microvoids) of 26% (0.26 volume fraction) are formed between the fine particles. Increase to%. In the actual system (low refractive index layer),
Due to the presence of some distribution of particle sizes, these values are not met. The porosity also changes depending on the conditions for forming the low-refractive-index layer (that is, the method of fusing the particles and the conditions for fusing). If the content of microvoids is too high, the mechanical strength of the film decreases, so that the volume fraction of microvoids is preferably 0.50 or less. Since a very small amount of binder is used in the present invention, the porosity changes depending on the ratio of the binder to the fine particles. If the microvoids (voids) thus formed have a size of several tens to several hundreds of nm (less than the wavelength of light), the material is selected from the viewpoint of the refractive index,
Then, by adjusting the volume fraction of the formed microvoids, a transparent film having a target refractive index can be formed.

In the present invention, since a small amount of binder is used in the low refractive index layer, it is necessary to use the minimum amount required to achieve the close contact between the fine particles so as not to overfill the microvoids formed between the fine particles. Preferred examples of the binder include various water-soluble polyfunctional epoxy monomers and water-dispersible polyfunctional isocyanates in the case of aqueous coating. In the case of applying an organic solvent, acrylic resins such as polymethyl methacrylate and polymethyl acrylate, (meth) acrylic monofunctional / polyfunctional monomers, oligomers and oligomers such as polyester acrylate and urethane acrylate can be exemplified. Particularly, from the viewpoint of film strength, the following specific examples can be given as those preferably used as the monofunctional / polyfunctional monomer. Examples of trifunctional or higher polyfunctional monomers include pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, and dipentaerythritol tetra (meth) acrylate. Acrylate, dipentaerythritol penta (meth) acrylate, pentaerythritol hexa (meth) acrylate, and the like. As the bifunctional monomer, ethylene glycol di (meth) acrylate, 1,
3 propylene glycol di (meth) acrylate, 1,
6 hexanediol di (meth) acrylate, etc.
Monofunctional monomers include methyl (meth) acrylate,
Examples include ethyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, and t-butyl acrylate.

In the case of water-based or alcohol-based coating, an organic-substituted silicon-based compound can be included in this. These silicon compounds have the general formula:

R ₁₁ aR ₁₂ bSiX _{4- (a + b)} (where R ₁₁ and R ₁₂ are each an alkyl group, an alkenyl group, an allyl group, or a carbon substituted with halogen, epoxy, amino, mercapto, methacryloyl or cyano, respectively) X represents a hydrogen group, X represents a hydrolyzable group selected from an alkoxyl group, an alkoxyalkoxyl group, a halogen atom and an acyloxy group, and under the condition that a + b is 1 or 2, a and b each represent 0, 1
Or 2. ) Or a hydrolysis product thereof. When the fluororesin fine particles are an aqueous dispersion, the use of the above water-soluble resin is preferred. When the fluororesin fine particles are dispersed in an organic solvent, they are sufficiently dissolved in the solvent used, have an affinity for the fine particles and the support, and have high transparency (that is, the acrylic resin and the cellulose derivative). Is preferably used. In addition, by using a monomer having a polymerizable group as described above as a binder, after forming a fine particle layer, crosslinking is performed by a treatment such as UV or heating, so that a stronger low refractive index layer is obtained.
As the amount of the binder to be added, the minimum amount required to obtain the adhesion between the fine particles is used. The amount of the binder added is generally preferably 25% by weight or less, particularly preferably 15% by weight or less.

The antireflection film of the present invention generally comprises a support and a low refractive index layer provided thereon. The support is usually a transparent film. Materials for forming the transparent film include cellulose derivatives (eg, diacetylcellulose, triacetylcellulose (TAC), propionylcellulose, brylcellulose, acetylpropionylcellulose, and nitrocellulose), polyamides, polycarbonates (eg, US Pat. No. 3,023,101). Described), polyesters (polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, poly-1,4-cyclohexane dimethylene terephthalate, polyethylene-1,2-diphenoxyethane-4,4'-dicarboxylate, and Tokubyosho) 48-4
0414), polystyrene, polyolefins (eg, polyethylene, polypropylene and polymethylpentene), polymethyl methacrylate, syndiotactic polystyrene, polysulfone,
Polyethersulfone, polyetherketone, polyetherimide and polyoxyethylene can be mentioned. Triacetyl cellulose, polycarbonate and polyethylene terephthalate are preferred. The refractive index of the transparent film is preferably from 1.40 to 1.60.

When the antireflection film of the present invention is a multilayer film, the low-refractive-index layer generally has at least one layer having a higher refractive index than the low-refractive-index layer. (Refractive index layer). As an organic material for forming a layer having a higher refractive index than the above, a thermoplastic resin (eg, polystyrene, polystyrene copolymer,
A polymer having an aromatic ring, a heterocyclic ring, an alicyclic group other than polycarbonate or polystyrene, or a polymer having a halogen group other than fluorine); a thermosetting resin composition (eg, a melamine resin, a phenol resin, or an epoxy resin) A curing agent); a urethane-forming composition (eg, a combination of an alicyclic or aromatic isocyanate and a polyol); and a radically polymerizable composition (a double bond is formed in the above compound (polymer or the like). A composition containing a modified resin or a prepolymer which is capable of radical curing by being introduced). Materials having high film forming properties are preferred. For the layer having a higher refractive index than the above, inorganic fine particles dispersed in an organic material can also be used. As the organic material used in the above, an inorganic fine particle generally has a high refractive index, so that a material having a lower refractive index than that of a case where the organic material is used alone can be used. As such material examples, in addition to the organic materials described above, vinyl-based copolymers including acrylics, polyesters, alkyd resins, cellulose-based polymers, urethane resins and various curing agents for curing these,
Various organic materials that are transparent and can stably disperse inorganic fine particles, such as a composition having a curable functional group, can be given. Particularly, from the viewpoint of film strength, the following specific examples can be given as those preferably used as the composition having the curable functional group. Trifunctional or higher functional monomers include pentaerythritol tetra (meth) acrylate and pentaerythritol tri (meth)
Acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, pentaerythritol hexa (meth) acrylate, and the like. Examples of the functional monomer include ethylene glycol di (meth) acrylate, 1,3 propylene glycol di (meth) acrylate, and 1,6 hexanediol di (meth) acrylate. Monofunctional monomers include methyl (meth) acrylate and ethyl ( Examples include (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, and t-butyl acrylate.

In the case of water-based coating or alcohol-based coating, an organic-substituted silicon-based compound can be included in this. These silicon compounds have the general formula:

R ₁₁ aR ₁₂ bSiX _{4- (a + b)} (where R ₁₁ and R ₁₂ are each an alkyl group, an alkenyl group, an allyl group, or a carbon substituted with halogen, epoxy, amino, mercapto, methacryloyl or cyano. X represents a hydrogen group, X represents a hydrolyzable group selected from an alkoxyl group, an alkoxyalkoxyl group, a halogen atom and an acyloxy group, and under the condition that a + b is 1 or 2, a and b each represent 0, 1
Or 2. ) Or a hydrolysis product thereof.

Preferred inorganic compounds of the inorganic fine particles dispersed therein include oxides of metal elements such as aluminum, titanium, zirconium, antimony and tin. These compounds are in the form of fine particles,
That is, it is commercially available as a powder or a colloidal dispersion in water and / or other solvents. These are further mixed and dispersed in the above organic material or organosilicon compound for use.

As a material for forming a layer having a higher refractive index, inorganic materials which are film-forming and can be dispersed in a solvent or are themselves liquid (eg, alkoxides of various elements, salts of organic acids, A coordination compound (eg, a chelate compound) bonded to a coordination compound, an active inorganic polymer) can be exemplified. Preferred examples thereof include titanium tetraethoxide, titanium tetra-i-propoxide, titanium tetra-n-propoxide, titanium tetra-n-butoxide, titanium tetra-sec-butoxide, titanium tetra-tert-butoxide, Aluminum triethoxide,
Aluminum tri-i-propoxide, aluminum tributoxide, antimony triethoxide, antimony tributoxide, zirconium tetraethoxide, zirconium tetra-i-propoxide, zirconium tetra-n-propoxide, zirconium tetra-n-butoxide, zirconium Metal alcoholate compounds such as tetra-sec-butoxide and zirconium tetra-tert-butoxide; diisopropoxytitanium bis (acetylacetonate), dibutoxytitanium bis (acetylacetonate), diethoxytitanium bis (acetylacetonate), Bis (acetylacetone zirconium), aluminum acetylacetonate, aluminum di-n-butoxide monoethylacetoacetate,
Chelating compounds such as aluminum di-i-propoxide monomethyl acetoacetate and tri-n-butoxide zirconium monoethyl acetoacetate; and active inorganic polymers mainly containing zirconium ammonium zirconate or zirconium. In addition to those described above, various alkyl silicates or hydrolysates thereof, particularly fine particles of silica, particularly silica gel dispersed in a colloidal form can be used as those having a relatively low refractive index but which can be used in combination with the above compounds. .

The antireflection film of the present invention can be treated so that the surface has an antiglare function (that is, a function of scattering incident light on the surface to prevent a scene around the film from shifting to the film surface). . For example, an antireflection film having such a function forms fine irregularities on the surface of a transparent film, and forms an antireflection film (eg, a low refractive index layer, etc.) on the surface.
Is obtained. The formation of the fine irregularities is performed, for example, by forming a layer containing inorganic or organic fine particles on the surface of the transparent film. Or,
Fine particles having a particle diameter of 50 nm to 5 μm, which are different from the fluororesin fine particles, are introduced into the coating solution for forming the low refractive index layer in an amount of 0.1 to 50% by weight of the fluororesin fine particles. Unevenness may be formed on the surface. An anti-reflection film having an anti-glare function (ie, an anti-glare treatment)
Generally, it has a haze of 3 to 30%.

The antireflection film of the present invention (preferably an antireflection film having an antiglare function) is used for a liquid crystal display (LC).
D), an image display device such as a plasma display (PDP), an electroluminescence display (ELD), and a cathode ray tube display (CRT).
In the image display device having such an antireflection film, reflection of incident light is prevented, and visibility is remarkably improved. A liquid crystal display (LCD) provided with the antireflection film of the present invention has, for example, the following configuration. A liquid crystal display comprising a pair of substrates having transparent electrodes, a nematic liquid crystal sealed between the substrates, and a polarizing plate disposed on both sides of the liquid crystal cell, wherein at least one of the polarizing plates has a surface on which the present invention is applied. Liquid crystal display device having an anti-reflection film.

The low-refractive-index layer of the antireflection film of the present invention may be formed, for example, by applying a coating solution (fluorine resin fine particles dispersed in water and / or an organic solvent) for forming this layer to a curtain flow coat or a dip coat. It is formed by applying to a transparent film or a high or middle refractive index layer or the like by an application method such as spin coating, roll coating or the like, and drying.

In the present invention, a hard coat layer, an anti-moisture layer, an anti-static layer and the like may be provided on the transparent film as an intermediate layer. As the hard coat layer, in addition to acrylic-based, urethane-based, and epoxy-based polymers and / or oligomers and monomers, silica-based materials can also be used.

[0054]

【Example】

Example 1 25 parts by weight of dipentaerythritol penta / hexaacrylate (trade name: DPHA, manufactured by Nippon Kayaku Co., Ltd.)
25 parts by weight of a urethane acrylate oligomer (trade name: UV-6300B, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.),
2 parts by weight of a photopolymerization initiator (trade name: Irgacure-90)
7, Ciba-Geigy) and 0.5 parts by weight of a sensitizer (trade name: Kayacure-DETX, manufactured by Nippon Kayaku Co., Ltd.)
Was dissolved in 50 parts by weight of methyl ethyl ketone, and the solution was applied onto a TAC film using a bar coater, and the applied film was irradiated with ultraviolet light to form a hard coat layer (layer thickness: 5
μm). Subsequently, fluororesin fine particles (average particle size: 30 nm, refractive index: 1.421) obtained by emulsion copolymerization of hexafluoroisopropyl methacrylate-divinylbenzene-hydroxyethyl methacrylate;
UV-6300B of the composition used for the hard coat layer
Wherein DP is replaced by DPHA (refractive index: 1.535)
(Solid content: 1% by weight; fluororesin fine particles / binder = 84/16, weight ratio), was applied onto the high refractive index layer using a spin coater, and dried at 120 ° C. By irradiating the coating film with ultraviolet rays, a low-refractive-index layer having a thickness of 91 nm comprising fluororesin fine particles and a very small amount of binder was formed, and an antireflection film was obtained. The refractive index of the low refractive index layer (n
layer) was determined from the following formula based on the reflectance (R) and the refractive index (nbase) of the TAC film (transparent support).

[0055]

(Equation 1)

The volume fraction (Vlayer) of the microvoids in the low-refractive-index layer is represented by the refractive index (nlayer) of the low-refractive-index layer,
The average refractive index (nmaterial) of the refractive index of the fluorine-containing fine particles and the refractive index of the binder was determined by the following equation. Vlayer = (nlayer-nmaterial) / (1-nmateri
al) As a result, the reflectance of the antireflection film (TAC film and low refractive index layer) is 1.75 at a wavelength of 550 nm.
It was 945%, and the refractive index of the low refractive index layer was calculated to be 1.400, indicating that the low refractive index layer contained microvoids of about 0.10 volume fraction. Further, when the low refractive index layer was observed with an electron microscope, it was confirmed that approximately three fluororesin fine particles overlapped in the film thickness direction to form microvoids. The pencil hardness was 3H, and the surface was not scratched by rubbing with # 0000 steel wool, indicating that the scratch resistance was excellent.

Example 2 25 parts by weight of dipentaerythritol penta / hexa
Crylate (trade name: DPHA, manufactured by Nippon Kayaku Co., Ltd.),
25 parts by weight of urethane acrylate oligomer (product
Name: UV-6300B, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
2 parts by weight of a photopolymerization initiator (trade name: Irgacure-90)
7, Ciba-Geigy) and 0.5 parts by weight of a sensitizer
(Product name: Kayacure-DETX, manufactured by Nippon Kayaku Co., Ltd.)
Coating solution in which is dissolved in 50 parts by weight of methyl ethyl ketone
On a TAC film using a bar coater,
The coating film is irradiated with ultraviolet light to form a hard coat layer (layer thickness: 5
μm). TiO_TwoAs a fine dispersion and binder
UV-6300B of the composition used for the hard coat layer
In which DPHA was replaced by DPHA (refractive index after polymerization: 1.
535) (solid content: 2% by weight, TiO2)_Two/
Binder = 22/78, weight ratio)
Coated with a spin coater and dried at 120 ° C
After that, ultraviolet irradiation is performed to obtain a medium refractive index layer (refractive index: 1.62,
(Layer thickness: 78 nm). TiO_TwoOf fine dispersion and above
Coating solution containing the binder (solid content: 2% by weight, TiO _Two
/ Binder = 68/32, weight ratio) on the middle refractive index layer
And then dried at 120 ° C using a spin coater
The coating film is irradiated with ultraviolet rays to form a high refractive index layer (refractive index: 2.
00, layer thickness: 127 nm). Furthermore, hexa
Fluoroisopropyl methacrylate-divinylbenze
By emulsion copolymerization of 1-hydroxyethyl methacrylate.
Resin particles (average particle size: 30 nm, refraction
Index: 1.421) and the bi-layer used for the middle / high refractive index layer.
(Refractive index: 1.535) to obtain a coating solution (solid
Form fraction: 1% by weight; fine particles of fluororesin / binder = 84/1
6, weight ratio) on the high refractive index layer using a spin coater.
After applying and drying at 120 ° C., the applied film is irradiated with ultraviolet rays.
This makes it possible to use fluororesin fine particles and a very small amount of binder.
Forming a low refractive index layer having a thickness of 91 nm to obtain an antireflection film.
Was. As a result, the refractive index of the low refractive index layer is 1.400.
Contains about 0.10 volume fraction of microvoids
It has been suggested. Furthermore, the low refractive index layer was observed with an electron microscope.
It was found that almost three fluororesin fine particles
It is recognized that they overlap to form microvoids
Was. Anti-reflection film (TAC film and low refractive index layer)
The anti-irradiation effect is in the wavelength range from 450 nm to 650 nm.
Has a reflectance of less than 0.5% and has been used in the past.
Must be equivalent to multi-layer anti-reflective coating by physical vapor deposition
all right. The pencil hardness is 3H, and the pencil hardness is # 0000.
Scratched with steel wool, no scratch on surface, scratch resistant
It turned out to be excellent.

Comparative Example Hexafluoroisopropyl methacrylate (trade name:
Viscort 6FM, manufactured by Osaka Organic Chemical Co., Ltd.), 0.48
Emulsion polymerization was carried out to obtain fluorine resin fine particles (average particle diameter: 30 nm, refractive index: 1.387). A dispersion medium of water / methanol = 9/1 in which 15 parts by weight of polyvinyl alcohol (trade name: PVA203, Kuraray Co., Ltd., refractive index: 1.520) is added as a binder to 85 parts by weight of the fluororesin fine particles. Triacetyl cellulose (TAC) coated with a hard coat layer in the same manner as in Examples 1 and 2 using the dispersed coating solution (solid content: 1% by weight)
The film is coated on the film using a spin coater and dried at a temperature of 40 ° C.
Was formed to obtain an antireflection film. Further, when the low refractive index layer was observed with an electron microscope, it was confirmed that approximately three fluororesin fine particles overlapped in the film thickness direction to form microvoids. The reflectance of the antireflection film (TAC film and low refractive index layer) is 1.331% (wavelength 55
0 nm light) and the refractive index of the low refractive index layer is 1.366 (containing about 0.10 volume fraction of microvoids).
It was calculated. However, it was inferior in scratch resistance, had a pencil hardness of B, and when rubbed with # 0000 steel wool, a part of the light interference layer dropped off.

[0059]

The low refractive index layer constituting the antireflection film of the present invention is formed of fluorine resin fine particles and microvoids formed between the fine particles. The low refractive index layer has a refractive index lower than that of the material and has an extremely low refractive index, and also has excellent scratch resistance because fine particles are tightly bound to each other via a very small amount of binder. In particular, an antireflection film using this low refractive index layer together with at least one layer having a high refractive index exhibits a high antireflection effect.

[Brief description of the drawings]

FIG. 1 shows a cross-sectional view of a typical example of an antireflection film of the present invention.

[Explanation of symbols]

 Reference Signs List 1 low refractive index layer 2 fluorine-containing fine particles 3, 6, 9 binder 4 high refractive index layer 5, 8 metal oxide fine particles 7 medium refractive index layer 10 hard coat layer 11 transparent film

Claims (4)

[Claims] 1. A low-refractive-index layer comprising microvoids formed between fine particles by stacking at least two fine particles of a fluoropolymer having an average particle size in the range of 5 to 200 nm on a substrate. Wherein the low refractive index layer comprises fluorine-containing polymer particles, a polymerizable monomer and / or a polymerizable oligomer and / or a polymerizable polymer. Characteristic anti-reflection film. 2. The light interference layer comprises a plurality of layers including at least one layer having a higher refractive index than any of a low refractive index layer and a substrate, and each layer has a common monomer and / or oligomer and / or The anti-reflection film according to claim 1, wherein a polymer is contained as a binder. 3. The method according to claim 1, further comprising a hard coat layer having a thickness of 0.5 to 10 μm between the light interference layer and a substrate on which the light interference layer is provided. The antireflection film as described in the above. 4. An image display device comprising the antireflection film according to claim 1.