JP7201965B2 - Optical laminate and image display device - Google Patents

Description

The present invention relates to an optical laminate and an image display device.

On the image display surface of an image display device such as a liquid crystal display (LCD), a cathode ray tube display (CRT), a plasma display (PDP), an electroluminescence display (ELD), a field emission display (FED), an observer and An antiglare film having an uneven surface and an antireflection film having an antireflection layer on the outermost surface are provided in order to suppress reflection of the background of the observer.

The antiglare film scatters external light on the uneven surface of the antiglare layer to suppress reflection of the observer and the background of the observer. and an antiglare layer having an uneven surface provided on the material.
The antiglare layer in such an antiglare film usually contains a binder resin and fine particles present in the binder resin for forming an uneven surface.
However, when such a conventional antiglare film is placed on the surface of an image display device, there is a risk that image light will be scattered by the uneven surface of the antiglare layer, resulting in so-called glare.

In order to solve such problems, it has been proposed to increase the internal haze of the antiglare film to suppress the glare. An antiglare film intended to suppress glare by increasing it is described, and for example, Patent Document 2 and the like disclose an antiglare film intended to suppress glare by increasing the internal haze by fine particles contained in the antiglare layer. is described.

However, conventional anti-glare films with increased internal haze are capable of suppressing glare, but have the problem of lowering the contrast and brightness of the image displayed on the image display device. In other words, with conventional anti-glare films, if the internal haze is increased in order to suppress the occurrence of glare, it will lead to a decrease in contrast and brightness. I had a problem.

JP 2014-126598 A JP 2016-035575 A

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical layered body and an image display device capable of suppressing the occurrence of glare, having excellent luminance and preventing a decrease in contrast.

The present invention provides an optical laminate having an optical control layer and an optical layer having an uneven surface, wherein the optical control layer has a low refractive index region and a refractive index higher than that of the low refractive index region. The low refractive index region and the high refractive index region are provided in a columnar shape continuously from one surface to the other surface of the optical control layer, and the optical When light is incident from the normal direction of one surface of the control layer and the transmitted light intensity is measured, the transmitted light intensity at a diffusion angle of 5° is T5, the transmitted light intensity at a diffusion angle of 10° is T10, and the diffusion angle is 20. The optical layered body satisfies the following formulas (1) and (2), where T20 is the transmitted light intensity at 40° and T40 is the transmitted light intensity at a diffusion angle of 40° .
T5/T10≦5 (1)
T20/T40≧50 (2)

In the optical laminate of the present invention, the low refractive index region preferably has a refractive index of 1.40 to 1.50, and the high refractive index region preferably has a refractive index of 1.50 to 1.65.
The shortest distance between adjacent low refractive index regions and/or the shortest distance between adjacent high refractive index regions at the interface on the optical layer side or the interface opposite to the optical layer side of the optical control layer is 0.1. It is preferably ˜15 μm.
In the optical layered body of the present invention, the optical layer having an uneven shape on the surface has an average distance between the unevenness of the surface as Sm, an average inclination angle of the unevenness as θa, and an arithmetic mean roughness of the unevenness as Ra. Assuming that the ten-point average roughness of the unevenness is Rz, it is preferable to satisfy the following formula.
50 μm<Sm<600 μm
0.1°<θa<1.5°
0.02 μm<Ra<0.25 μm
0.30 μm<Rz<2.00 μm
Further, it is preferable that the optical layer having an uneven surface contains silica fine particles, organic fine particles, and a binder resin, and the uneven surface is formed of the silica fine particles and the organic fine particles.

The present invention also provides an image display device comprising the optical layered body of the present invention.
The present invention will be described in detail below.

As a result of intensive studies, the present inventors have found that, in a conventional antiglare film in which fine particles are added to a light diffusion layer or the like for the purpose of suppressing glare to give a high internal haze, light incident on the light diffusion layer is refracted against fine particles and emitted from the light diffusion layer to suppress glare. Furthermore, it was found that total reflection at the interface (surface) with the outside and an excessively large refraction angle of the light emitted from the light diffusing layer cause the contrast and brightness of the display screen to decrease.
As a result of further studies based on such knowledge, it was found that in an optical layered body having a structure in which an optical control layer and an optical layer having an uneven surface are stacked, the optical control layer has regions having different refractive indices continuously. By forming it in the thickness direction, it is possible to suppress a decrease in contrast and brightness when applied to an image display device, and to exhibit excellent anti-glare performance. The present invention has been completed. rice field.

The optical laminate of the present invention has an optical control layer and an optical layer having an uneven surface.
In the optical laminate of the present invention, the optical control layer and the optical layer having an uneven surface are preferably directly laminated. Between the control layer and the optical layer, a gap (air layer) or any layer such as a known transparent substrate layer or clear hard coat layer may be provided.
The optical layered body of the present invention may be in the form of a film in which the optical control layer and the optical layer are self-supporting, or the optical control layer may be laminated on a light-transmitting substrate.

The light-transmitting substrate is not particularly limited as long as it has light-transmitting properties. Examples include a cellulose acylate substrate, a cycloolefin polymer substrate, a polycarbonate substrate, an acrylate-based polymer substrate, a polyester substrate, or , glass substrates, and the like.

Examples of the cellulose acylate base material include cellulose triacetate base material and cellulose diacetate base material.
Examples of the cycloolefin polymer substrate include substrates made of polymers such as norbornene-based monomers and monocyclic cycloolefin monomers.

Examples of the polycarbonate base material include aromatic polycarbonate base materials based on bisphenols (bisphenol A, etc.), aliphatic polycarbonate base materials such as diethylene glycol bisallyl carbonate, and the like.

Examples of the acrylate-based polymer base include polymethyl (meth)acrylate base, polyethyl (meth)acrylate base, and methyl (meth)acrylate-butyl (meth)acrylate copolymer base. materials. In this specification, (meth)acrylic acid means acrylic acid or methacrylic acid.

Examples of the polyester base material include base materials containing at least one of polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate as a constituent component.

Examples of the glass substrate include glass substrates such as soda lime silica glass, borosilicate glass, and alkali-free glass.

Among these, the cellulose acylate base is preferred because of its excellent retardation and easy adhesion to the polarizer, and among the cellulose acylate bases, the triacetyl cellulose base (TAC base) is more preferred. The triacetylcellulose base material is a light-transmitting base material capable of having an average light transmittance of 50% or more in the visible light range of 380 to 780 nm. The triacetylcellulose base material preferably has an average light transmittance of 70% or more, more preferably 85% or more.
In addition to pure triacetyl cellulose, the triacetyl cellulose base material may also be a fatty acid that forms an ester with cellulose, such as cellulose acetate propionate or cellulose acetate butyrate, in combination with a component other than acetic acid. good too. In addition, other cellulose lower fatty acid esters such as diacetyl cellulose, or various additives such as plasticizers, ultraviolet absorbers, and lubricants may be added to these triacetyl celluloses, if necessary.

A cycloolefin polymer base material is preferable from the viewpoint of excellent retardation and heat resistance, and a polyester base material is preferable from the viewpoint of mechanical properties and heat resistance.

Although the thickness of the light-transmitting substrate is not particularly limited, it can be 5 μm or more and 1000 μm or less, and the lower limit of the thickness of the light-transmitting substrate is preferably 15 μm or more from the viewpoint of handling properties. 25 μm or more is more preferable. The upper limit of the thickness of the light-transmitting substrate is preferably 80 μm or less from the viewpoint of thinning.

The optical control layer is preferably a layer laminated on the light-transmitting substrate, and has a low refractive index region and a high refractive index region having a higher refractive index than the low refractive index region. The low refractive index region and the high refractive index region are provided in a columnar shape continuously from one surface to the other surface of the optical control layer. The optical control layer having such a structure has the effect of suppressing glare caused by the optical layer, which will be described later, by, for example, emitting light incident from the interface on the side of the light-transmitting substrate in an appropriately diffused state. .
FIG. 1 is a cross-sectional view schematically showing a part of the optical control layer in the optical laminate of the present invention. As shown in FIG. 1, in the optical laminate of the present invention, the optical control layer 10 , a low refractive index region 11 and a high refractive index region 12 are continuously provided in a columnar shape in the thickness direction. For this reason, the incident light from the side surface of the light-transmissive substrate (not shown) repeats total reflection when the incident angle at the interface between the low refractive index region 11 and the high refractive index region 12 is equal to or less than the critical angle. Then, the incident light is emitted from the side surface of the optical control layer 10 opposite to the light-transmitting substrate side. When the incident angle of the incident light at the interface between the low refractive index region 11 and the high refractive index region 12 exceeds the critical angle, the incident light is not totally reflected but is transmitted and emitted from the optical control layer 10 . Since the incident light is transmitted through the optical control layer 10 in this manner, the light that hits the fine particles and is reflected back or refracted by the fine particles exits the light diffusion layer like the conventional light diffusion layer containing the fine particles described above. It is possible to suppress total reflection at the interface (surface) with the outside or excessive refraction angle of the light emitted from the light diffusion layer, and as a result, the optical laminate of the present invention is added to the image display device. When the body is used, it is possible to suppress the decrease in the contrast and brightness of the display screen.

In the optical laminate of the present invention, the shape of the low refractive index region and the high refractive index region in the optical control layer is not particularly limited as long as it has a columnar structure that is continuous in the thickness direction of the optical control layer. First, for example, like the optical control layer 20 shown in FIG. ), or a structure (a sea-island structure) in which a plurality of cylindrical low refractive index regions 31 are provided in a high refractive index region 32, as in the optical control layer 30 shown in FIG. .
With a louver structure like the optical control layer 20 shown in FIG. 2, the light transmitted through the optical control layer 20 is emitted in a state of being diffused in one direction, that is, in the horizontal direction in FIG. With the sea-island structure of the optical control layer 30, the light transmitted through the optical control layer 30 is emitted in all directions, that is, isotropically diffused.
In the optical layered body of the present invention, for example, the low refractive index region and the high refractive index region shown in FIGS. 2 and 3 may be provided oppositely. In addition, the low refractive index region 21 and the high refractive index region 22 in FIG. 2 may be plate-shaped with uneven thickness, and the low refractive index region 31 shown in FIG. Both sides may be circular, elliptical, polygonal, or any other shape.
FIG. 2 is a perspective view schematically showing one example of the optical layered body of the present invention, and FIG. 3 is a perspective view schematically showing another example of the optical layered body of the present invention.

The optical control layer having such a low refractive index region and a high refractive index region is formed by, for example, stirring two polymerizable compounds having different refractive indices under high temperature conditions of 40 to 80° C. to form a uniform liquid mixture. , After adding additives such as a photopolymerization initiator to the mixed solution as desired, the mixture is stirred until uniform, and a diluent solvent is added as necessary to achieve the desired viscosity. It can be formed by using the composition for the optical control layer prepared as above.

Of the two polymerizable compounds having different refractive indices, the type of polymerizable compound having a higher refractive index (hereinafter also referred to as component (A)) is not particularly limited, but its main component contains a plurality of aromatic rings. It is preferable to use a (meth)acrylic acid ester.
By including a specific (meth) acrylic acid ester as the component (A), sufficient compatibility with a polymerizable compound having a lower refractive index (hereinafter, also referred to as component (B)) at the monomer stage However, it is presumed that the compatibility with the component (B) can be reduced to a predetermined range at the stage of multiple connections in the polymerization process, and the predetermined internal structure can be formed more efficiently. be done.
Furthermore, by including a specific (meth)acrylic acid ester as the component (A), the refractive index of the high refractive index region derived from the component (A) in the optical control layer is increased, thereby increasing the refractive index of the high refractive index region derived from the component (A). ) component, the difference from the refractive index of the low refractive index region can be adjusted to a predetermined value or more. Therefore, by including a specific (meth)acrylic acid ester as the component (A), in combination with the properties of the component (B) described later, a predetermined optical control layer composed of regions with different refractive indices can be efficiently obtained. be able to.
In the present specification, "(meth)acrylic acid ester containing multiple aromatic rings" means a compound having multiple aromatic rings in the ester residue portion of (meth)acrylic acid ester, and "( "Meth)acrylic acid" means acrylic acid and methacrylic acid.

Examples of (meth)acrylic acid esters containing a plurality of aromatic rings as the component (A) include biphenyl (meth)acrylate, naphthyl (meth)acrylate, anthracyl (meth)acrylate, (meth)acryl Examples include benzylphenyl acid, fluorene (meth)acrylate, and the like, and those partially substituted with halogen, alkyl, alkoxy, halogenated alkyl, and the like.

The weight molecular weight of component (A) is preferably in the range of 200-2500.
Therefore, the molecular weight of the component (A) is more preferably in the range of 240-1500, more preferably in the range of 260-1000.
The weight average molecular weight of the component (A) can be obtained from the molecular composition and the calculated value obtained from the atomic weight of the constituent atoms, and is measured as the weight average molecular weight using gel permeation chromatography (GPC). can also

It is preferable to set the refractive index of the component (A) to a value within the range of 1.50 to 1.65.
By setting the refractive index of the component (A) to a value within this range, the refractive index of the high refractive index region derived from the component (A) and the refractive index of the low refractive index region derived from the component (B) difference can be more easily adjusted to more efficiently obtain an optical control layer with a predetermined internal structure.
If the refractive index of the component (A) is less than 1.50, the difference from the refractive index of the component (B) will be too small, making it difficult to obtain an effective light diffusion angle region. On the other hand, when the refractive index of the component (A) exceeds 1.65, although the difference from the refractive index of the component (B) becomes large, even an apparent compatible state with the component (B) It can be difficult to form.
The refractive index of component (A) is more preferably in the range of 1.55 to 1.60, more preferably in the range of 1.56 to 1.59.
In addition, the refractive index of the (A) component mentioned above means the refractive index of the (A) component before hardening by light irradiation.
Further, the refractive index can be measured according to JIS K0062, for example.

The content of component (A) in the composition for the optical control layer is preferably in the range of 25 to 400 parts by mass per 100 parts by mass of component (B) described below. When the amount is less than 25 parts by mass, the ratio of component (A) to component (B) is reduced, and the width of the high refractive index region derived from component (A) is reduced to the low refractive index derived from component (B). It may become too small compared to the width of the region, making it difficult to obtain an optical control layer with a predetermined internal structure. In addition, the length of the predetermined internal structure in the thickness direction of the optical control layer becomes insufficient, and the light diffusibility may not be exhibited. On the other hand, when the content of component (A) exceeds 400 parts by mass, the proportion of component (A) relative to component (B) increases, and the width of the high refractive index region derived from component (A) increases. , the width of the low refractive index region derived from the component (B) becomes excessively large, and conversely, it may become difficult to obtain an optical control layer with a predetermined structure. In addition, the length of the predetermined internal structure in the thickness direction of the optical control layer becomes insufficient, and the light diffusibility may not be exhibited. Therefore, the content of the component (A) is more preferably in the range of 40 to 300 parts by mass, more preferably in the range of 50 to 200 parts by mass, per 100 parts by mass of the component (B). It is more preferable that

Of the two polymerizable compounds having different refractive indices, the type of the polymerizable compound having a lower refractive index (component (B)) is not particularly limited, and examples thereof include compounds having functional groups such as acrylates. and compounds having one or more unsaturated bonds.
Examples of the compound having an unsaturated bond in 1 above include ethyl (meth)acrylate and ethylhexyl (meth)acrylate.
Examples of the compound having two or more unsaturated bonds include diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene di(meth)acrylate, (meth)acrylate, dioxane glycol di(meth)acrylate, methoxypolyethylene glycol di(meth)acrylate, methoxypolypropylene glycol di(meth)acrylate, dicyclopentane di(meth)acrylate, tricyclodecane di(meth)acrylate, tri Methylolpropane tri(meth)(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, tripentaerythritol octa(meth)acrylate, tetrapentaerythritol deca (Meth)acrylate, isocyanurate tri(meth)acrylate, isocyanurate di(meth)acrylate, epoxy (meth)acrylate, urethane (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, silicone (meth)acrylate acrylates and the like.

It is preferable to set the refractive index of the component (B) to a value within the range of 1.40 to 1.50. By setting the refractive index of component (B) to a value within this range, the difference between the refractive index of the high refractive index region derived from component (A) and the refractive index of the low refractive index region derived from component (B) is It can be adjusted more easily to obtain an optical control layer with predetermined polygonal areas more efficiently.
That is, when the refractive index of the component (B) is less than 1.40, although the difference from the refractive index of the component (A) is large, the compatibility with the component (A) is extremely deteriorated. may not be able to form the internal structure of On the other hand, when the refractive index of the component (B) exceeds 1.50, the difference from the refractive index of the component (A) becomes too small, making it difficult to obtain the desired incident angle dependence. Sometimes.
Therefore, the refractive index of the component (B) is more preferably in the range of 1.45 to 1.49, more preferably in the range of 1.46 to 1.48.
In addition, the refractive index of the (B) component mentioned above means the refractive index of the (B) component before hardening by light irradiation.

Moreover, it is preferable that the difference between the refractive index of the component (A) and the refractive index of the component (B) be 0.01 or more.
By setting the refractive index difference to a value within a predetermined range, it is possible to obtain an optical control layer having better incident angle dependence in light transmission and diffusion and a wider light diffusion incident angle region. .
That is, when the difference in refractive index is less than 0.01, the range of angles in which incident light is totally reflected within the predetermined optical control layer becomes narrower, and the opening angle in light diffusion may become excessively narrow. be. On the other hand, if the difference in refractive index becomes an excessively large value, the compatibility between the components (A) and (B) is so deteriorated that the desired internal structure may not be formed.
Therefore, it is more preferable that the difference between the refractive index of the component (A) and the refractive index of the component (B) is in the range of 0.05 to 0.5, more preferably 0.1 to 0.2. It is more preferable to set the value within the range of

The content of component (B) in the composition for optical control is preferably in the range of 10 to 80% by mass with respect to 100% by mass of the total amount of the composition for optical control layer. When the content of the component (B) is less than 10% by mass, the proportion of the component (B) relative to the component (A) decreases, and the width of the low refractive index region derived from the component (B) becomes This is because the width becomes excessively small compared to the width of the high refractive index region derived from the component (A), and it may become difficult to obtain a predetermined internal structure having good incident angle dependence. In addition, the length of the predetermined internal structure in the thickness direction of the optical control layer may be insufficient. On the other hand, when the content of the component (B) exceeds 80% by mass, the ratio of the component (B) to the component (A) increases, and the low refractive index region derived from the component (B) The width becomes excessively large compared to the width of the high refractive index region derived from the component (A), and conversely, it may be difficult to obtain a predetermined internal structure with good incident angle dependence. Because. Also, the length of the predetermined internal structure in the thickness direction of the optical control layer may be insufficient.
Therefore, the content of component (B) is more preferably in the range of 20 to 70% by mass, more preferably 30 to 60% by mass, relative to 100% by mass of the total amount of the composition for the optical control layer. A value within the range is more preferable.

If desired, the composition for the optical control layer preferably contains a photopolymerization initiator as the component (C).
By including the photopolymerization initiator, a predetermined internal structure can be efficiently formed when the composition for the optical control layer is irradiated with active energy rays.
Here, the photopolymerization initiator refers to a compound that generates radical species upon irradiation with active energy rays such as ultraviolet rays.

Such photopolymerization initiators include, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone. , 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl] -2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4-diethylaminobenzophenone, dichlorobenzophenone, 2 -methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylamine benzoate, oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propane and the like, one of which may be used alone, or two or more may be used in combination.
When the photopolymerization initiator is contained, the content may be in the range of 0.2 to 20 parts by weight with respect to 100 parts by weight of the total amount of components (A) and (B). Preferably, the value is in the range of 0.5 to 15 parts by weight, and more preferably in the range of 1 to 10 parts by weight.

Further, other additives can be added as appropriate within a range that does not impair the effects of the present invention.
Other additives include, for example, antioxidants, ultraviolet absorbers, antistatic agents, polymerization accelerators, polymerization inhibitors, infrared absorbers, plasticizers, diluent solvents, and leveling agents.
The content of other additives is generally preferably within the range of 0.01 to 5 parts by mass with respect to 100 parts by mass of the total amount of components (A) and (B). A value in the range of 0.02 to 3 parts by mass is more preferable, and a value in the range of 0.05 to 2 parts by mass is even more preferable.

In order to form the optical control layer using the composition for the optical control layer, first, the composition for the optical control layer is applied onto the above-described light-transmitting substrate to form a coating layer.
Examples of methods for applying the composition for the optical control layer onto the light-transmissive substrate include knife coating, roll coating, bar coating, blade coating, die coating, comma coating, and gravure coating. It can be performed by a conventionally known method such as a method.
At this time, it is preferable to set the thickness of the coating layer to a value within the range of 100 to 700 μm.

Next, the coating layer is irradiated with an active energy ray to form an optical control layer comprising a plurality of regions having different refractive indices.
Specifically, the coating layer is irradiated with parallel light having a high degree of parallelism.
Here, the term "parallel light" means substantially parallel light that does not spread when viewed from any direction.
More specifically, for example, as shown in FIG. 6(a), irradiation light 50 from a point light source 202 is converted into parallel light 60 by a lens 204, and then the coating layer 101 provided on the process sheet 102 is irradiated with the light. Alternatively, as shown in FIGS. 6B and 6C, the irradiation light 50 from the linear light source 125 is converted into parallel light 60 by the irradiation light collimating member 200 (200a, 200b), and then the coating layer 101 It is preferable to irradiate to

In addition, as shown in FIG. 6(d), the irradiation light collimating member 200, among the direct light from the linear light source 125, in a direction parallel to the axial direction of the linear light source 125, in which the light direction is random, For example, direct light from the linear light source 125 can be converted into parallel light by unifying the direction of light using the light shielding member 210 such as the plate member 210a and the cylindrical member 210b.
More specifically, of the direct light from the linear light source 125, light that is less parallel to the light shielding member 210 such as the plate-like member 210a or the cylindrical member 210b comes into contact with these and is absorbed.
Therefore, only light that is highly parallel to the light shielding member 210 such as the plate member 210a and the cylindrical member 210b, that is, only parallel light passes through the irradiation light parallelizing member 200. As a result, the linear light source 125 is converted into parallel light by the irradiation light collimating member 200 .
The material of the light shielding member 210 such as the plate-like member 210a and the cylindrical member 210b is not particularly limited as long as it can absorb light with low parallelism to the light shielding member 210. For example, heat-resistant black A coated Ulster steel plate or the like can be used.

Moreover, it is preferable to set the parallelism of the irradiation light to a value of 10° or less.
The reason for this is that the optical control layer having the predetermined internal structure can be efficiently and stably formed by setting the parallelism of the irradiation light to a value within this range.
Therefore, it is more preferable to set the parallelism of the irradiation light to a value of 5° or less, and more preferably to a value of 2° or less.

As for the irradiation angle of the irradiation light, as shown in FIG. 7, the irradiation angle θ3 when the angle of the normal to the surface of the coating layer 101 is 0° is normally within the range of −80 to 80°. value.
The reason for this is that when the irradiation angle is outside the range of −80 to 80°, the influence of reflection on the surface of the coating layer 101 increases, and the optical function layer having the predetermined internal structure described above cannot be formed. This is because it may be difficult to
In addition, FIG. 7 is explanatory drawing of an active energy irradiation process.

Moreover, although ultraviolet rays, electron beams, and the like can be used as irradiation light, it is preferable to use ultraviolet rays.
The reason for this is that in the case of electron beams, the polymerization rate is very high, so that the components (A) and (B) cannot be sufficiently phase-separated during the polymerization process, and the optical control layer having the above-described predetermined internal structure is formed. This is because it may be difficult to form. On the other hand, when compared with visible light, etc., ultraviolet rays have a wide variety of ultraviolet curable resins that are cured by irradiation and photopolymerization initiators that can be used. This is because it is possible to expand the range of choices for

As for the irradiation conditions of the ultraviolet rays, it is preferable to set the peak illuminance on the surface of the coating layer to a value within the range of 0.1 to 10 mW/cm ² .
The reason for this is that if the peak illuminance is less than 0.1 mW/cm ² , it may be difficult to clearly form the optical control layer having the predetermined internal structure described above. On the other hand, if the peak illuminance exceeds 10 mW/cm ² , the components (A) and (B) are cured before the phase separation progresses, and conversely, the optical control layer with a specific structure becomes clear. This is because it may be difficult to form the
Therefore, it is more preferable to set the peak illuminance of the coating layer surface in ultraviolet irradiation to a value within the range of 0.3 to 8 mW/cm ² , and more preferably to a value within the range of 0.5 to 6 mW/cm ² . preferable.

Further, it is more preferable to set the integrated amount of light on the coating layer surface in ultraviolet irradiation to a value within the range of 5 to 200 mJ/cm ² .
The reason for this is that if the integrated amount of light is less than 5 mJ/cm ² , it may be difficult to sufficiently extend the high refractive index region and the low refractive index region from above to below. be. On the other hand, if the integrated amount of light exceeds 200 mJ/cm ² , the obtained optical control layer may be colored.
Therefore, it is more preferable to set the integrated amount of light on the coating layer surface in ultraviolet irradiation to a value within the range of 7 to 150 mJ/cm ² , and more preferably to a value within the range of 10 to 100 mJ/cm ² .
In addition, it is preferable to optimize the peak illuminance and the integrated amount of light according to the internal structure formed in the film.

Moreover, it is preferable to irradiate the coating layer with an active energy ray in a non-oxygen atmosphere. By performing active energy ray irradiation in a non-oxygen atmosphere, the influence of oxygen inhibition can be suppressed, and an optical control layer having a predetermined internal structure can be efficiently formed.
If the active energy ray irradiation is performed in an oxygen atmosphere rather than in a non-oxygen atmosphere, it is possible to form a predetermined internal structure at a very shallow position near the surface of the coating layer by irradiating with high illuminance. Although it can be done, it may be difficult to obtain the refractive index difference necessary for light diffusion. On the other hand, when irradiated with low illuminance, it may be difficult to form a predetermined internal structure due to the influence of oxygen inhibition.
The term "under a non-oxygen atmosphere" means that the upper surface of the coating layer is not in direct contact with an oxygen atmosphere or an oxygen-containing atmosphere.
Therefore, for example, it is possible to laminate a film on the upper surface of the coating layer, or to perform active energy ray irradiation in a state where the air is replaced with nitrogen gas and nitrogen purge is performed, in a "non-oxygen atmosphere". corresponds to active energy ray irradiation.

Further, as the active energy ray irradiation under the above-mentioned "non-oxygen atmosphere", it is particularly preferable to perform the active energy ray irradiation in a state where the active energy ray permeable sheet is laminated on the upper surface of the coating layer.
By performing active energy ray irradiation in this manner, the influence of oxygen inhibition can be effectively suppressed, and an optical control layer having a predetermined internal structure can be formed more efficiently.
For example, by laminating an active energy ray-transmitting sheet on the upper surface of the coating layer, while stably preventing the upper surface of the coating layer from coming into contact with oxygen, the sheet is transmitted and efficiently coated. Active energy rays can be applied to the layer.
As the active energy ray-transmitting sheet, any sheet can be used without any particular limitation as long as it can transmit the active energy ray.

In the active energy ray-transmitting sheet, the arithmetic average roughness of the surface on the side not in contact with the coating layer is preferably 2 μm or less, more preferably less than 1 μm. With such an arithmetic mean roughness, it is possible to effectively prevent the active energy ray from being diffused by the active energy ray permeable sheet, and to efficiently form the predetermined internal structure.
The above arithmetic mean roughness can be determined according to JIS B 0601.
From the same point of view, the haze value of the active energy ray-transmitting sheet is preferably within the range of 0 to 8%, particularly preferably within the range of 0.1 to 5%.
The haze value can be obtained according to JIS K7136.

Further, the image definition (slit width: 0.125 mm, 0.25 mm, 0.5 mm, 1 mm and 2 mm) of the active energy ray-transmitting sheet is preferably a value within the range of 200 to 500. , 300-490 are particularly preferred. If the image definition is within this range, the active energy ray can be transmitted through the coating layer without loss in the sheet, and the desired internal structure can be efficiently formed.
The image definition can be determined according to JIS K7374.
From the same point of view, the transmittance of the active energy ray-transmitting sheet to light with a wavelength of 360 nm is preferably in the range of 30 to 100%, more preferably in the range of 45 to 95%. Especially preferred.

In addition to the above steps, it is also preferable to irradiate active energy rays so that the amount of light sufficient to cure the coating layer is sufficient.
Since the purpose of the active energy rays at this time is to sufficiently cure the coating layer, it is preferable to use irradiation light that travels in random directions.

In the predetermined internal structure of the optical control layer, the difference in refractive index between regions having different refractive indices, that is, the difference between the refractive index of the high refractive index region and the refractive index of the low refractive index region is 0.01 or more. value is preferred. By setting the difference in refractive index to a value of 0.01 or more, it is possible to stably reflect incident light within a predetermined internal structure.
The refractive index difference is preferably 0.05 or more, more preferably 0.1 or more. It should be noted that the larger the refractive index difference described above, the better, but from the viewpoint of selecting a material capable of forming a predetermined internal structure, the upper limit is considered to be about 0.3.

Also, in the predetermined internal structure, it is preferable to set the refractive index of the high refractive index region to a value within the range of 1.50 to 1.65. When the refractive index of the high refractive index region is less than 1.50, the difference from the low refractive index region becomes too small, and it may become difficult to obtain a predetermined internal structure. When the refractive index of exceeds 1.65, the compatibility between materials in the composition for the optical function layer may become excessively low.
It is more preferable to set the refractive index of the high refractive index region in the predetermined internal structure to a value within the range of 1.55 to 1.60, and further to a value within the range of 1.56 to 1.59. preferable.
The refractive index of the high refractive index region can be measured according to JIS K 0062, for example.

Also, in the predetermined internal structure, it is preferable to set the refractive index of the low refractive index region to a value within the range of 1.40 to 1.50. If the refractive index of the low refractive index region is less than 1.40, the rigidity of the resulting optical control layer may decrease. becomes too small, making it difficult to obtain a desired internal structure.
The refractive index of the low refractive index region in the predetermined internal structure is more preferably a value within the range of 1.45 to 1.49, more preferably a value within the range of 1.46 to 1.48. preferable.
The refractive index of the low refractive index region can be measured according to JIS K 0062, for example.

In the optical layered body of the present invention, the shortest distance between adjacent low refractive index regions and/or is preferably 0.1 to 15 μm. By setting the interval between these regions to a value within the range of 0.1 to 15 μm, the incident light can be stably reflected within the predetermined internal structure.
If the distance between the adjacent high refractive index regions and the adjacent low refractive index regions is less than 0.1 μm, it may be difficult to exhibit light diffusion regardless of the incident angle of incident light. On the other hand, when the interval between the adjacent high refractive index regions and the adjacent low refractive index regions exceeds 15 μm, the amount of light traveling straight through the predetermined internal structure increases, and the uniformity of diffused light may deteriorate. be.
Therefore, at the interface on the optical layer side of the optical control layer or the interface on the side opposite to the optical layer side, the shortest distance between adjacent low refractive index regions and the shortest distance between adjacent high refractive index regions are 0.5 to 10 μm. is more preferably a value within the range of 1 to 5 μm.
Here, the shortest distance between adjacent low refractive index regions and/or the shortest distance between adjacent high refractive index regions at the optical layer side interface or the interface opposite to the optical layer side of the optical control layer is the The optical laminate of the invention can be measured by observing with an optical digital microscope from the optical layer side or the side opposite to the optical layer side.
The shortest distance between adjacent low refractive index regions and/or the shortest distance between adjacent high refractive index regions at the optical layer side interface or the interface opposite to the optical layer side of the optical control layer is 2 or more. can be regarded as the interval between the adjacent high refractive index region and the adjacent low refractive index region in the cross section in the thickness direction of the optical control layer where the high refractive index region and two or more low refractive index regions appear. The distance between the adjacent high refractive index region and the adjacent low refractive index region in the cross section in the thickness direction of the optical control layer can also be measured by observing with an optical digital microscope.

It is preferable that the film thickness of the optical control layer is set to a value within the range of 30 to 300 μm. If the total film thickness of the optical control layer is less than 30 μm, the amount of incident light that travels straight through the internal structure may increase, making it difficult to exhibit light diffusion. When forming a predetermined internal structure by irradiating the composition for the optical control layer with an active energy ray, the initially formed internal structure causes the direction of photopolymerization to diffuse, resulting in the formation of the predetermined internal structure. can be difficult to form. The thickness of the optical control layer is more preferably in the range of 40 to 250 μm, more preferably in the range of 50 to 200 μm.

When light is incident on one surface of the optical control layer from the normal direction of the optical control layer and the transmitted light intensity is measured, the transmitted light intensity at a diffusion angle of 5° is T5, and the transmitted light intensity at a diffusion angle of 10° is T5. When the transmitted light intensity is T10, the transmitted light intensity at a diffusion angle of 20° is T20, and the transmitted light intensity at a diffusion angle of 40° is T40, it is preferable to satisfy the following formulas (1) and (2).
T5/T10≦5 (1)
T20/T40≧50 (2)
By satisfying the above formula (1), a change in intensity of transmitted light in the vicinity of the specular transmission direction (diffusion angle of 0°) is reduced, so that there is sufficient diffused light to suppress glare. The left side of the above formula (1) is more preferably 4 or less, still more preferably 3 or less.
Further, by satisfying the above formula (2), diffused light is rapidly reduced at an angle away from the specular transmission direction, so deterioration of brightness and contrast can be suppressed. The left side of the above formula (2) is more preferably 100 or more, still more preferably 200 or more.
In addition, in the specification of the present invention, the measurement of the transmitted light intensity can be performed with a variable angle photometer. Although the goniophotometer is not particularly limited, "GC5000L" manufactured by Nippon Denshoku Industries Co., Ltd. was used in the present invention.
The transmitted light intensity is a value at each diffusion angle when calibration is performed without a sample installed and the transmitted light intensity in the specular transmission direction (diffusion angle of 0°) at that time is 100000. In the measurement of the transmitted light intensity, the sample is placed in the apparatus, a light beam is incident from the normal direction of the sample surface, and the specular transmission direction of the transmitted and diffused light is assumed to be a diffusion angle of 0 °. Measure the intensity of the transmitted diffuse light. Here, the transmitted light intensity is assumed to be the average value of the - side and the + side. For example, the transmitted light intensity at a diffusion angle of 10° is obtained as the average value of the transmitted light intensity at a diffusion angle of −10° and the transmitted light intensity at a diffusion angle of +10°. Further, when the denominator is 0 in calculating the above formulas (1) and (2), the left side of each formula is regarded as infinite.
The above formulas (1) and (2) can be satisfactorily satisfied, for example, by appropriately controlling the parameters of the uneven surface shape of the optical layer, which will be described later.

In the optical laminate of the present invention, an optical layer having an uneven surface is laminated on the side of the optical control layer opposite to the light-transmitting substrate side.
The optical layer has an uneven surface and is a layer that ensures the antiglare performance of the optical layered body of the present invention.
In order to obtain the uneven shape described above, (1) a composition containing fine particles and a binder resin is applied to a light-transmitting substrate to form unevenness, and (2) two types of mutually incompatible binder resins are included. The composition is applied to a light-transmitting substrate to form unevenness by phase separation. (3) A binder resin is applied to the light-transmitting substrate and an embossing roll having unevenness is transferred to form unevenness. and the like. Among these, the method (1) is preferable from the viewpoint of ease of production, and will be described in detail below.

When the optical layer is obtained by the method (1) above, the optical layer preferably contains inorganic fine particles and/or organic fine particles and a binder resin as fine particles, and the uneven shape of the surface of the optical layer is It is more preferable to be formed of aggregates of inorganic fine particles and organic fine particles, which will be described later.
Such uneven shapes formed on the surface of the optical layer are formed on the surface of the optical layer by single fine particles (eg, organic fine particles) or aggregates of single particles (eg, aggregates of inorganic fine particles). It is preferable that the slope of the convex portion is gentler and the shape is smoother than the concave and convex shape described above.
This is presumed to be because the inorganic fine particles and the organic fine particles are distributed in a specific state in the optical layer, as will be described later.

It is preferable that the inorganic fine particles form aggregates and are loosely and densely contained in the optical layer. Since the aggregates of the inorganic fine particles are coarsely and densely distributed in the optical layer, a smooth irregular shape is formed on the surface of the optical layer.
The above-mentioned "sparsely and densely distributed in the optical layer" means that in the optical layer, the aggregates of the inorganic fine particles are densely distributed (electron microscope (preferably transmission type such as TEM, STEM) a region where the area ratio of aggregates of inorganic fine particles in a 2 μm square observation region is 5% or more when an arbitrary cross section in the thickness direction of the optical layer is observed under conditions of a magnification of 10,000 times at , and When an arbitrary cross section in the thickness direction of the optical layer is observed at a magnification of 10,000 times with an electron microscope (preferably a transmission type such as TEM or STEM) in a region where aggregates of inorganic fine particles are coarsely distributed. , areas in which the area ratio of aggregates of inorganic fine particles in a 2 μm square observation area is less than 1%). That is, the aggregates of the inorganic fine particles are non-uniformly dispersed in the optical layer.
The distribution of such aggregates of inorganic fine particles can be easily determined by cross-sectional electron microscope observation in the thickness direction of the optical layer. The area ratio of the inorganic fine particle aggregates can be calculated using, for example, image analysis software.
Although such inorganic fine particles are not particularly limited, silica fine particles are preferable, for example. Hereinafter, the inorganic fine particles will be described as silica fine particles.

The silica fine particles are preferably surface-treated. By surface-treating the silica fine particles, it is possible to suitably control the extent to which the aggregates of the silica fine particles are coarsely and densely distributed in the optical layer, and the silica fine particles are densely distributed around the organic fine particles. You can control the effect within a moderate range. In addition, it is possible to improve the chemical resistance and saponification resistance of the silica fine particles themselves.

Examples of the surface treatment include a method of treating the silica fine particles with a silane compound having an octyl group.
Here, hydroxyl groups (silanol groups) are usually present on the surface of the silica fine particles, but the hydroxyl groups on the surface of the silica fine particles are reduced by the surface treatment, and the silica fine particles are treated by the BET method. As the specific surface area to be measured becomes smaller, the silica fine particles can be prevented from excessively aggregating, and the above-described effects are exhibited.

Further, the silica fine particles are preferably made of amorphous silica. When the silica fine particles are made of crystalline silica, the Lewis acidity of the silica fine particles becomes strong due to lattice defects contained in the crystal structure, and excessive aggregation of the silica fine particles described above may not be controlled.

As such fine silica particles, for example, fumed silica is preferably used because it is likely to agglomerate itself and easily form aggregates described later. Here, the fumed silica refers to amorphous silica having a particle size of 200 nm or less produced by a dry method, and is obtained by reacting a volatile compound containing silicon in a gas phase. Specific examples include silicon compounds such as those produced by hydrolyzing SiCl ₄ in a flame of oxygen and hydrogen. Specific examples thereof include AEROSIL R805 (manufactured by Nippon Aerosil Co., Ltd.).

Although the content of the silica fine particles is not particularly limited, it is preferably 0.1 to 5.0% by mass in the optical layer. If it is less than 0.1% by mass, it may not be possible to sufficiently form a dense distribution around the organic fine particles described above, and if it exceeds 5.0% by mass, aggregates are excessively generated, resulting in internal diffusion and/or Since the optical layer has large surface unevenness, the problem of white blurring may occur. A more preferable lower limit is 0.5% by mass, and a more preferable upper limit is 3.0% by mass.

The fine silica particles preferably have an average primary particle size of 1 to 100 nm. If it is less than 1 nm, it may not be possible to sufficiently form a dense distribution around the organic fine particles, and if it exceeds 100 nm, it may not be possible to sufficiently form a dense distribution around the organic fine particles. The light is diffused, and the darkroom contrast of the image display device using the optical layered body of the present invention may be deteriorated. A more preferable lower limit is 5 nm, and a more preferable upper limit is 50 nm.
The average primary particle diameter of the silica fine particles is a value measured from an image of a cross-sectional electron microscope (preferably a transmission type such as TEM or STEM with a magnification of 50,000 times or more) using image processing software. be.

Further, in the present invention, it is preferable that the aggregate of the silica fine particles forms a structure in which the silica fine particles described above are linked in a beaded (pearl necklace shape) in the optical layer.
By forming aggregates in which the silica fine particles are linked in a beaded manner in the optical layer, the uneven surface shape of the optical layer can be suitably smoothed as described later. The structure in which the silica fine particles are linked in a beaded shape includes, for example, a structure in which the silica fine particles are linked in a straight line (straight chain structure), a structure in which a plurality of the straight chain structures are entangled, and the straight chain structure. An arbitrary structure such as a branched structure having one or two or more side chains in which a plurality of silica fine particles are continuously formed may be mentioned.

Further, the aggregate of silica fine particles preferably has an average particle size of 100 nm to 1 μm. If it is less than 100 nm, it may not be possible to sufficiently form a dense distribution around the organic fine particles, and if it exceeds 1 μm, it may not be possible to sufficiently form a dense distribution around the organic fine particles. Light is diffused by the aggregates, and the darkroom contrast of an image display device using the optical layered body of the present invention may be poor. A more preferable lower limit of the average particle size of the aggregates is 200 nm, and a more preferable upper limit thereof is 800 nm.
The average particle diameter of the aggregates of silica fine particles is determined by observing a cross-sectional electron microscope (about 10,000 to 20,000 times) and selecting a 5 μm square region containing a large amount of aggregates of silica fine particles. The particle diameters of aggregates of fine particles are measured, and the particle diameters of the top 10 aggregates of silica fine particles are averaged. In addition, the above-mentioned "particle diameter of the aggregate of silica fine particles" is defined as two such that when the cross section of the aggregate of silica fine particles is sandwiched between two arbitrary parallel straight lines, the distance between the two straight lines is the maximum. Measured as the distance between straight lines in a combination of straight lines in a book. In addition, the particle diameter of the aggregate of silica fine particles may be calculated using image analysis software.

Preferably, the optical layer contains organic fine particles, and aggregates of the silica fine particles are densely distributed around the organic fine particles.
As described above, the silica fine particle aggregates are contained in the optical layer in a coarse and dense manner, and in the optical layer, a large number of silica fine particle aggregates are present around the organic fine particles. It is preferable that a region in which only the aggregates of the silica fine particles are densely distributed is formed.
Here, when the cross section of the optical layer is observed with an electron microscope, aggregates of silica fine particles densely distributed around the organic fine particles are found not only in the cross section passing through the center of the organic fine particles, but also in the cross section that deviates from the center of the organic fine particles. A dense distribution is also observed in the cross section.
In addition, the above-mentioned "the silica fine particle aggregates are densely distributed around the organic fine particles" means that the optical layer was observed under the condition of 20,000 times magnification with an electron microscope (preferably a transmission type such as TEM or STEM). When the section where the organic fine particles are observed in the thickness direction is observed under a microscope, the area ratio of the silica fine particle aggregates in the area excluding the organic fine particles within the circumference of 200 nm outside the organic fine particles is 10. % or more.

In addition, the aggregate of silica fine particles densely distributed around the organic fine particles adheres to the surface of the organic fine particles and/or is impregnated with a part of the silica fine particles constituting the aggregate. is preferable (hereinbelow, such aggregates of silica fine particles are also referred to as adhering to the surfaces of organic fine particles). Since the aggregates of the silica fine particles are attached to the surface of the organic fine particles, the different organic fine particles are obtained by utilizing the cohesive force acting between the aggregates of the silica fine particles attached to the surfaces of the different organic fine particles. can bring them together. Therefore, even if the amount of the organic fine particles added is small, it is possible to form an uneven shape having sufficient antiglare properties.
It should be noted that gathering the organic fine particles does not mean that the organic fine particles are completely adhered to each other, but that the closest distance between the organic fine particles when observing the cross section of the optical layer is smaller than the average particle diameter of the particles. Alternatively, it means that a plurality of aggregates of the silica fine particles are continuously connected between the organic fine particles.
Aggregates of silica fine particles adhering to the surface of the organic fine particles can be easily confirmed by observing a cross section of the optical layer with an electron microscope.

Examples of the method for adhering the aggregates of the silica fine particles to the surface of the organic fine particles include a method of hydrophilizing the surface of the organic fine particles, as described later.
Further, as a method of impregnating a part of the silica fine particles constituting the silica fine particle aggregate from the surface of the organic fine particles to the inside thereof, for example, a method of lowering the degree of cross-linking of the organic fine particles when forming the optical layer. and a method in which a solvent capable of swelling organic fine particles is used in the composition for an optical layer, which will be described later.
It is preferable that the organic fine particles have aggregates of the silica fine particles evenly adhered to almost the entire surface thereof.
The ratio of the silica fine particle aggregates attached to the surface of the organic fine particles to the silica fine particle aggregates densely distributed around the organic fine particles is preferably determined by an electron microscope (TEM, STEM, etc. transmission type). ) under the condition of a magnification of 20,000 times, a region within a circumference of 200 nm outside the organic fine particles and excluding the organic fine particles when a cross section in which the organic fine particles are observed in the thickness direction of the optical layer is observed under a microscope. Among the silica fine particle aggregates, the area ratio is preferably 50% or more. If it is less than 50%, the effect of gathering together the organic fine particles in the optical layer may be insufficient, making it impossible to form unevenness sufficient to provide sufficient antiglare performance.

Further, when the surface of the organic fine particles is partially impregnated with the silica fine particles constituting the aggregate of the silica fine particles, the aggregate of the silica fine particles is impregnated up to 500 nm from the surface of the organic fine particles. preferably. In order to impregnate the surface of the organic fine particles with the silica fine particles constituting aggregates of silica fine particles exceeding 500 nm, it is necessary to swell the organic fine particles excessively. Therefore, a uniform coating film may not be obtained. In addition, it may not be possible to form a gentle concave-convex shape, which will be described later, on the surface of the optical layer.

Since the optical layer contains the aggregates of silica fine particles linked in a beaded state and the organic fine particles in such a specific state, the optical layer has irregularities formed by single fine particles or aggregates thereof. The slope of the convex portion is gentler than the shape, resulting in a smooth shape. As a result, the optical layered body of the present invention can improve bright room and dark room contrast while maintaining antiglare properties. Since the uneven convex portions formed on the surface of the optical layer have a gentle slope and a smooth shape, only the edge portion of the image reflected on the surface of the optical layer can be made invisible. Anti-glare property is guaranteed. Furthermore, since the optical layer having such an uneven shape can eliminate large diffusion, it is possible to prevent the generation of stray light, and it is also possible to have an appropriate amount of specular transmission. In addition, the contrast in a bright room and a dark room can be excellent (having a feeling of blackness).
This is presumed to be due to the following reasons.
That is, when the optical layer composition is applied and dried to evaporate the solvent, if the viscosity is low, the binder resin tends to conform to the shape of the organic fine particles. Furthermore, the volume of the binder resin shrinks when it hardens, but the organic fine particles do not shrink. Therefore, when only the binder resin shrinks, the projections formed on the surface at positions corresponding to the organic fine particles become steep. slope.
However, since aggregates of silica fine particles are densely distributed around the organic fine particles, the viscosity of the optical layer composition around the organic fine particles increases, and when the solvent evaporates, the binder resin changes to the shape of the organic fine particles. In addition, the binder (composed of binder resin and silica fine particles) in that portion is difficult to cure and shrink, and as a result, the protrusions formed on the surface of the position corresponding to the organic fine particles tend to have a gentle slope. .
For this reason, it is presumed that the inclination angle of the uneven shape (convex portion) formed on the surface of the optical layer by the organic fine particles is gentler than the inclination angle of the uneven shape (convex portion) formed by the fine particles alone. be.

In addition, the organic fine particles are preferably fine particles having relatively uniform particle diameters that mainly form unevenness on the surface of the optical layer. It is preferably an aggregate that is distributed and has a relatively large variation in particle size in the optical layer. Since the optical layer contains two kinds of fine particles having such a relationship in particle size, the optical layered body of the present invention can have a uniform particle size of the organic fine particles in the optical layer. It is easy to form a structure in which aggregates of silica fine particles having a large particle diameter are incorporated, and the above-described smooth uneven shape can be suitably formed on the surface of the optical layer.
Here, the above-mentioned "fine particles with relatively uniform particle diameters" means that when the average particle diameter of the fine particles by weight average is MV, the cumulative 25% diameter is d25, and the cumulative 75% diameter is d75, (d75-d25) /MV is 0.25 or less, and the above-mentioned "aggregate with relatively large variation in particle size" means the case where (d75-d25)/MV exceeds 0.25. In addition, the cumulative 25% diameter refers to the particle diameter at 25% by mass, counting from the smaller particles in the particle size distribution, and the cumulative 75% diameter means 75 masses counted in the same manner. %. The average particle size, cumulative 25% diameter, and cumulative 75% diameter of fine particles by weight average can be measured as a weight average diameter by the Coulter counter method.

Further, in the optical layer, the organic fine particles and silica fine particles preferably have a spherical shape in a single particle state. Since the single particles of the organic fine particles and the silica fine particles have such a spherical shape, when the optical layered body of the present invention is applied to an image display device, a high-contrast display image can be obtained.
In addition, the above-mentioned "spherical shape" includes, for example, a true spherical shape, an elliptical spherical shape, and the like, and is meant to exclude so-called irregular shapes.

The organic fine particles are fine particles that mainly form the uneven surface shape of the optical layer, and are fine particles whose refractive index and particle size can be easily controlled. By containing such organic fine particles, it becomes easy to control the size of the concave-convex shape formed in the optical layer and the refractive index of the optical layer, and it is possible to control the anti-glare property and suppress the occurrence of glare and white blurring. .

The organic fine particles are made of at least one material selected from the group consisting of acrylic resins, polystyrene resins, styrene-acrylic copolymers, polyethylene resins, epoxy resins, silicone resins, polyvinylidene fluoride resins, and polyethylene fluoride resins. Fine particles are preferred. Among them, styrene-acrylic copolymer fine particles are preferably used.

The organic fine particles are preferably surface-hydrophilized. When the organic fine particles are surface-hydrophilized, the affinity with the silica fine particles is increased, and the aggregates of the silica fine particles can adhere to the surfaces of the organic fine particles. In addition, it becomes easy to densely distribute the aggregates of the silica fine particles around the organic fine particles.
The hydrophilization treatment is not particularly limited and includes known methods. Examples thereof include a method of copolymerizing a monomer having a functional group such as a carboxylic acid group or a hydroxyl group on the surface of the organic fine particles.
In general, organic fine particles whose surface has been hydrophilized cannot be loosely gathered in the optical layer, so that the surface of the optical layer cannot be formed with a sufficient irregular shape, resulting in poor antiglare performance. Become. However, in the present invention, the silica fine particles form aggregates and are loosely and densely contained in the optical layer, and the silica fine particle aggregates are densely distributed around the organic fine particles. Even an optical layer containing treated organic fine particles can form a desired uneven shape.

The content of the organic fine particles is preferably 0.5 to 10.0% by mass in the optical layer. If it is less than 0.5% by mass, the antiglare performance may be insufficient, and if it exceeds 10.0% by mass, the problem of white blurring may occur, and the optical layered body of the present invention may be deteriorated. When used in an image display device, the contrast of the displayed image may be poor. A more preferable lower limit is 1.0% by mass, and a more preferable upper limit is 8.0% by mass.

The size of the organic fine particles is appropriately determined according to the thickness of the optical layer, etc., but the average particle size is preferably 0.3 to 5.0 μm, for example. If it is less than 0.3 μm, the dispersibility of the organic fine particles may become uncontrollable. A more preferable lower limit is 1.0 μm, and a more preferable upper limit is 3.0 μm.
Further, the average particle diameter of the organic fine particles is preferably 20 to 60% of the thickness of the optical layer. If it exceeds 60%, the organic fine particles may protrude to the outermost surface of the coating film layer, and the unevenness caused by the organic fine particles may become steep. If it is less than 20%, it may become impossible to form a sufficient irregular shape on the surface of the optical layer, resulting in insufficient antiglare performance.
The average particle diameter of the organic fine particles can be measured as a weight average diameter by the Coulter counter method when measuring the organic fine particles alone. On the other hand, the average particle size of the organic fine particles in the optical layer is obtained by averaging the maximum sizes of 10 particles in observation of the optical layer with a transmission optical microscope. Alternatively, if it is not suitable, diffusion particles 30 that are of the same type and are observed to have approximately the same particle size in electron microscopic (preferably transmission type such as TEM or STEM) observation of a cross section passing through the vicinity of the particle center. It is a value calculated as the average value of the selected pieces (the number n is increased because it is unknown which part of the particle the cross section is) and the maximum particle size of the cross section is measured. Since both are determined from images, they may be calculated using image analysis software.

Moreover, the thickness of the optical layer is preferably 2.0 to 7.0 μm. If it is less than 2.0 μm, the surface of the optical layer may be easily damaged, and if it exceeds 7.0 μm, the optical layer may be easily cracked. A more preferable range for the thickness of the optical layer is 2.0 to 5.0 μm. The thickness of the optical layer can be measured by cross-sectional microscopic observation.

In the optical layer, the silica fine particles and the organic fine particles are preferably dispersed in a binder resin.
As the binder resin, it is preferable to use a polyfunctional acrylate monomer containing no hydroxyl group in the molecule as a main material. The above-mentioned "mainly composed of a polyfunctional acrylate monomer containing no hydroxyl group in the molecule" means that the content of the polyfunctional acrylate monomer containing no hydroxyl group in the molecule is the highest among the raw material monomers of the binder resin. do. Since the polyfunctional acrylate monomer containing no hydroxyl group in the molecule is a hydrophobic monomer, in the optical laminate of the present invention, the binder resin constituting the optical layer is preferably a hydrophobic resin. When the binder resin is mainly composed of a hydrophilic resin having a hydroxyl group, a highly polar solvent (eg, isopropyl alcohol) described later is difficult to evaporate, making it difficult for the silica fine particles to adhere to and/or impregnate the organic fine particles. As a result, aggregation of the silica fine particles alone proceeds thereafter, and there is a risk of forming protrusions that worsen the glare on the surface of the optical layer.

Examples of polyfunctional acrylate monomers containing no hydroxyl group in the molecule include pentaerythritol tetraacrylate (PETTA), 1,6-hexanediol diacrylate (HDDA), dipropylene glycol diacrylate (DPGDA), tripropylene glycol diacrylate. Acrylate (TPGDA), PO-modified neopentyl glycol diacrylate, tricyclodecanedimethanol diacrylate, trimethylolpropane triacrylate (TMPTA), trimethylolpropane ethoxy triacrylate, dipentaerythritol hexaacrylate (DPHA), pentaerythritol ethoxytetra Acrylate, ditrimethylolpropane tetraacrylate, and the like. Among them, pentaerythritol tetraacrylate (PETTA) is preferably used.

As other binder resins, transparent ones are preferable. For example, ionizing radiation-curable resins, which are resins that are cured by ultraviolet rays or electron beams, are preferably cured by irradiation with ultraviolet rays or electron beams.
In this specification, the term "resin" is a concept that includes monomers, oligomers, polymers, etc., unless otherwise specified.

Examples of the ionizing radiation-curable resin include compounds having one or more unsaturated bonds, such as compounds having functional groups such as acrylates. Examples of compounds having one unsaturated bond include ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, N-vinylpyrrolidone and the like. Examples of compounds having two or more unsaturated bonds include trimethylolpropane tri(meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol. Hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate ) acrylate, dipentaerythritol penta(meth)acrylate, tripentaerythritol octa(meth)acrylate, tetrapentaerythritol deca(meth)acrylate, isocyanurate tri(meth)acrylate, isocyanurate di(meth)acrylate, polyester tri(meth)acrylate ) acrylate, polyester di (meth) acrylate, bisphenol di (meth) acrylate, diglycerin tetra (meth) acrylate, adamantyl di (meth) acrylate, isobornyl di (meth) acrylate, dicyclopentane di (meth) acrylate, tricyclode Polyfunctional compounds such as Kandi(meth)acrylate and the like can be mentioned. In addition, in this specification, "(meth)acrylate" refers to methacrylate and acrylate. Further, in the present invention, as the ionizing radiation-curable resin, the above-described compound modified with PO, EO, or the like can also be used.

In addition to the above compounds, relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, etc. having unsaturated double bonds are also used. It can be used as an ionizing radiation curable resin.

The above ionizing radiation-curable resin is used in combination with a solvent-drying resin (a resin such as a thermoplastic resin that forms a film simply by drying the solvent added to adjust the solid content at the time of coating). can also By using the solvent-drying type resin together, it is possible to effectively prevent film defects on the coating surface of the coating liquid when forming the optical layer.
The solvent-drying resin that can be used in combination with the ionizing radiation-curable resin is not particularly limited, and generally thermoplastic resins can be used.
The thermoplastic resin is not particularly limited, and examples thereof include styrene-based resins, (meth)acrylic-based resins, vinyl acetate-based resins, vinyl ether-based resins, halogen-containing resins, alicyclic olefin-based resins, polycarbonate-based resins, and polyester-based resins. Resins, polyamide-based resins, cellulose derivatives, silicone-based resins, rubbers, elastomers, and the like can be mentioned. The thermoplastic resin is preferably amorphous and soluble in an organic solvent (in particular, a common solvent capable of dissolving a plurality of polymers and curable compounds). In particular, styrene-based resins, (meth)acrylic-based resins, alicyclic olefin-based resins, polyester-based resins, cellulose derivatives (cellulose esters, etc.), and the like are preferable from the viewpoint of film formability, transparency, and weather resistance.

Moreover, the optical layer may contain a thermosetting resin.
The thermosetting resin is not particularly limited, and examples thereof include phenol resins, urea resins, diallyl phthalate resins, melamine resins, guanamine resins, unsaturated polyester resins, polyurethane resins, epoxy resins, aminoalkyd resins, and melamine-urea cocondensation. Resins, silicon resins, polysiloxane resins and the like can be mentioned.

The optical layer containing the silica fine particles, the organic fine particles, and the binder resin is formed by, for example, applying the optical layer composition containing the silica fine particles, the organic fine particles, the monomer components of the binder resin, and the solvent onto a polyester base material. It can be formed by curing a coating film formed by drying by irradiation with ionizing radiation or the like.

In the optical layer composition, the silica fine particles form the above aggregates in the composition, but are preferably in a state of being uniformly dispersed. It is preferable that the particles are distributed and further densely distributed around the organic fine particles. Unless the aggregates of the silica fine particles are uniformly dispersed in the optical layer composition, aggregation proceeds excessively in the optical layer composition, resulting in huge aggregates of the silica fine particles. , it becomes impossible to form an optical layer having a smooth uneven shape as described above.
Here, since the silica fine particles are a material capable of increasing the viscosity of the optical layer composition, the inclusion of the silica fine particles can suppress sedimentation of the organic fine particles contained in the optical layer composition. . That is, the silica fine particles are presumed to have the function of promoting the formation of a predetermined distribution of aggregates of the organic fine particles and the silica fine particles, and also the function of improving the pot life of the optical layer composition.

In addition, the silica fine particles are dispersed uniformly as aggregates in the optical layer composition, and the aggregates of the silica fine particles are coarse and dense in the coating film, and around the organic fine particles. As a method for densely distributing, for example, a method of adding a predetermined amount of a solvent having high polarity and a high volatilization rate as a solvent to be added to the optical layer composition can be mentioned. By containing such a solvent having a high polarity and a high volatilization rate, it is possible to prevent excessive agglomeration of aggregates of silica fine particles in the optical layer composition. On the other hand, when forming a coating film by coating and drying it on the polyester base material, the solvent with a high polarity and a high volatilization rate volatilizes before other solvents, so the composition at the time of coating film formation is denatured, and as a result, the silica fine particle aggregates gather around the organic fine particles in the coating film, and the silica fine particle aggregates also gather together, resulting in a coarse and dense state of the silica fine particle aggregates. In addition, a densely distributed state can be formed around the organic fine particles.
In this specification, the term "highly polar solvent" means a solvent having a solubility parameter of 10 [(cal/ ^cm3 ) ^1/2 ] or more, and the term "a solvent with a high volatilization rate" refers to relative evaporation A solvent with a velocity of 150 or higher is meant. Therefore, the above-mentioned "solvent with high polarity and high volatilization rate" means a solvent that satisfies both requirements of the above-mentioned "solvent with high polarity" and "solvent with high volatilization rate".
As used herein, the solubility parameter is calculated by the method of Fedors. The Fedors method is described, for example, in "SP Value Basics/Applications and Calculation Methods" (written by Hideki Yamamoto, published by Information Organization Co., Ltd., 2005). In the Fedors method, the solubility parameter is calculated from the following formula.
Solubility parameter = [ΣE _coh /ΣV] ²
In the above formula, E _coh is the cohesive energy density and V is the molar molecular volume. Solubility parameters can be calculated by obtaining ΣE _coh and ΣV, which are the sums of E _coh and V, based on E _coh and V determined for each atomic group.
In the present specification, the relative evaporation rate refers to the relative evaporation rate when the evaporation rate of n-butyl acetate is 100, and is an evaporation rate measured in accordance with ASTM D3539-87, which is expressed by the following formula: Calculated by Specifically, it is calculated by measuring the evaporation time of n-butyl acetate and the evaporation time of each solvent at 25° C. under dry air.
Relative evaporation rate = (Time required for 90% by weight of n-butyl acetate to evaporate)/(Time required for 90% by weight of measured solvent to evaporate) x 100

Examples of the solvent having a high polarity and a high volatilization rate include ethanol and isopropyl alcohol. Among them, isopropyl alcohol is preferably used.
Moreover, the content of isopropyl alcohol in the solvent is preferably 20% by mass or more in the total solvent. If it is less than 20% by mass, aggregates of silica fine particles may occur in the optical layer composition. The isopropyl alcohol content is preferably 40% by mass or less.

Examples of other solvents contained in the optical layer composition include ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), ethers (dioxane, tetrahydrofuran, etc.), and aliphatic hydrocarbons (hexane, etc.). , alicyclic hydrocarbons (cyclohexane, etc.), aromatic hydrocarbons (toluene, xylene, etc.), halogenated carbons (dichloromethane, dichloroethane, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, etc.), alcohols (butanol, cyclohexanol, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, etc.), cellosolve acetates, sulfoxides (dimethyl sulfoxide, etc.), amides (dimethylformamide, dimethylacetamide, etc.), etc., and mixtures thereof. may be

The optical layer composition preferably further contains a photopolymerization initiator.
The photopolymerization initiator is not particularly limited, and known ones can be used. phenones, benzils, benzoins, acylphosphine oxides. Moreover, it is preferable to mix and use a photosensitizer, and specific examples thereof include n-butylamine, triethylamine, poly-n-butylphosphine, and the like.

As the photopolymerization initiator, when the binder resin is a resin system having a radically polymerizable unsaturated group, acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether, etc. may be used alone or in combination. preferable. Further, when the binder resin is a resin system having a cationic polymerizable functional group, the photopolymerization initiator includes aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, metallocene compounds, benzoin sulfonate esters, and the like. are preferably used alone or as a mixture.

The content of the photopolymerization initiator in the optical layer composition is preferably 0.5 to 10.0 parts by mass with respect to 100 parts by mass of the binder resin. If it is less than 0.5 parts by mass, the hard coat performance of the optical layer to be formed may be insufficient. I don't like it.

The content ratio (solid content) of the raw material in the optical layer composition is not particularly limited, but is usually 5 to 70% by mass, preferably 25 to 60% by mass.

Conventionally known dispersants, surfactants, antistatic agents, and silane cups are added to the optical layer composition according to the purpose of increasing the hardness of the optical layer, suppressing curing shrinkage, controlling the refractive index, and the like. Ringing agents, thickeners, anti-coloring agents, coloring agents (pigments, dyes), defoaming agents, leveling agents, flame retardants, UV absorbers, adhesion promoters, polymerization inhibitors, antioxidants, surface modifiers, A lubricating agent or the like may be added.
Examples of the leveling agent include silicone oil and fluorine-based surfactants. Preferably, fluorine-based surfactants containing perfluoroalkyl groups are used to prevent the optical layer from forming a Benard cell structure. preferred from When a resin composition containing a solvent is applied and dried, a difference in surface tension or the like is generated between the coating surface and the inner surface within the coating film, thereby causing a large number of convection currents within the coating film. A structure caused by this convection is called a Benard cell structure, and causes problems such as citrus peel and coating defects in the formed optical layer.
In addition, in the Benard cell structure, the unevenness of the surface of the optical layer becomes excessively large, which adversely affects white blurring and glare. The use of a leveling agent as described above can prevent this convection, so that not only is it possible to obtain an uneven film free from defects and unevenness, but also the shape of the unevenness can be easily adjusted.

Further, the optical layer composition may be used by mixing a photosensitizer, and specific examples thereof include n-butylamine, triethylamine, poly-n-butylphosphine, and the like.

The method for preparing the optical layer composition is not particularly limited as long as each component can be uniformly mixed, and for example, it can be carried out using a known device such as a paint shaker, bead mill, kneader, mixer, and the like.

The method for applying the optical layer composition onto the polyester substrate is not particularly limited. Known methods such as a printing method, a screen printing method, and a speed coater method can be used.
After applying the optical layer composition by any of the above methods, the formed coating film is transported to a heated zone to dry the coating film and evaporate the solvent by various known methods. Here, by selecting the solvent relative evaporation rate, solid content concentration, coating liquid temperature, drying temperature, drying air speed, drying time, solvent atmospheric concentration in the drying zone, etc., the distribution state of the aggregates of organic fine particles and silica fine particles can be adjusted.
In particular, the method of adjusting the distribution state of aggregates of organic fine particles and silica fine particles by selecting drying conditions is simple and preferable. The specific drying temperature is preferably 30 to 120° C., and the drying air speed is preferably 0.2 to 50 m/s. And the distribution state of aggregates of silica fine particles can be adjusted to a desired state.

Further, as a method of irradiating ionizing radiation when curing the coating film after drying, for example, a light source such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a black light fluorescent lamp, a metal halide lamp is used. method.
As the wavelength of ultraviolet rays, a wavelength range of 190 to 380 nm can be used. Specific examples of the electron beam source include various electron beam accelerators such as Cockcroftwald type, Vandegraft type, resonance transformer type, insulating core transformer type, linear type, dynamitron type, and high frequency type.

In another aspect of the optical layer, the inorganic fine particles are roughly distributed around the organic fine particles, and are uniformly distributed in the optical layer except around the organic fine particles. is preferred.
By controlling the inorganic fine particles and the organic fine particles so as to be in such a specific state, the uneven shape is formed more uniformly and evenly as compared with the optical layers of conventional optical laminates. An optical layered body having such an optical layer can suppress the occurrence of glare at an extremely high level while having good antiglare properties, and can obtain an excellent display image with high contrast. .
In addition, the above-mentioned "the inorganic fine particles are roughly distributed around the organic fine particles" means that the thickness of the optical layer is measured under the condition of 10,000 times magnification with an electron microscope (preferably a transmission type such as TEM or STEM). Mn is the area ratio of the inorganic fine particles in the area excluding the organic fine particles within the circumference 500 nm outside the organic fine particles when a cross section in which the organic fine particles are observed is observed under a microscope. It means that Mf/Mn is 1.5 or more, where Mf is the area ratio of the inorganic fine particles in the region outside the circumference of 500 nm from the center.
Further, the above-mentioned "uniformly distributed in the antiglare layer" means that the organic fine particles in the thickness direction of the optical layer are observed under the condition of 10,000 times magnification with an electron microscope (preferably a transmission type such as TEM or STEM). When 10 arbitrary cross-sections are observed from unobserved positions, the area ratio of silica fine particles in a 5 μm square observation area is measured for each cross-section, and the average value is M and the standard deviation is S. , S/M≦0.1.

In the optical layer according to the above another aspect, the inorganic fine particles, the organic fine particles, the binder resin, the photopolymerization initiator, and the solvent can be the same as those described in the optical layer described above. It is preferable that the organic fine particles in the optical layer according to the aspect of (1) are not surface-hydrophilized. If the organic fine particles are surface-hydrophilized, the affinity with the inorganic fine particles may be too high, making it difficult to distribute the inorganic fine particles roughly around the organic fine particles.
In addition, the method for producing the optical body according to the above another aspect is not particularly limited as long as it is a method that can be controlled so that the organic fine particles and the inorganic fine particles are contained in the optical layer in the above-described state. It can be manufactured by a layer manufacturing method.

In the optical layer according to another aspect, the content of the silica fine particles is not particularly limited, but is preferably 1.0 to 10.0% by mass in the optical layer. If it is less than 1.0% by mass, the organic fine particles described above may not be present so as to form a uniform uneven shape. If it rises too much, the applicability may deteriorate. A more preferable lower limit is 3.0% by mass, and a more preferable upper limit is 8.0% by mass.

In the optical layer according to another aspect, the content of the organic fine particles is preferably 1 to 50% by mass in solid content in the antiglare layer composition. If it is less than 1% by mass, the antiglare performance of the laminate to be produced may be insufficient, and if it exceeds 50% by mass, the problem of white blurring may occur, and the produced laminate may not be imaged. When used in a display device, the contrast of the displayed image may be poor. A more preferable lower limit is 5% by mass, and a more preferable upper limit is 20% by mass.

In the optical layer according to the above another aspect, the size of the organic fine particles is appropriately determined according to the thickness of the antiglare layer to be formed. Preferably. If it is less than 0.3 μm, the dispersibility of the organic fine particles may become uncontrollable, and if it exceeds 6.0 μm, the unevenness of the surface of the antiglare layer becomes large, which may cause glare. A more preferable lower limit is 2.0 μm, and a more preferable upper limit is 4.0 μm.
The average particle diameter of the organic fine particles is preferably 20 to 90% of the thickness of the antiglare layer to be formed. If it exceeds 90%, there is a possibility that the unevenness of the antiglare layer may be formed due to the strong influence of the unevenness of the film thickness. If it is less than 20%, it may become impossible to form a sufficient irregular shape on the surface of the antiglare layer, resulting in insufficient antiglare performance.

なお、上記式（ａ）中、Ａ＝Ｌｘ×Ｌｙを表す。
また、Ｘ軸方向にｉ番目、Ｙ軸方向にｊ番目の点の位置における高さをＺｉ，ｊとすると、上記算術平均粗さＳａは、下記式（ｂ）で算出される。

なお、上記式（ｂ）中、Ｎは、全点数を表す。
このような３次元での算術平均粗さＳａを得る装置としては、接触式表面粗さ計や非接触式の表面粗さ計（例えば、干渉顕微鏡、共焦点顕微鏡、原子間力顕微鏡等）が挙げられる。これらの中でも、測定の簡便性から干渉顕微鏡を用いて測定することが好ましい。このような干渉顕微鏡としては、Ｚｙｇｏ社製の「Ｎｅｗ Ｖｉｅｗ」シリーズ等が挙げられる。 Further, the uneven shape of the surface of the optical layer according to the above another aspect is obtained by dividing the surface of the optical layer into 100 μm square measurement areas, obtaining the arithmetic average roughness Sa in each measurement area, and calculating the arithmetic average roughness Sa is Ma, and the standard deviation of the arithmetic mean roughness Sa is Sq, the ratio of Ma to Sq (Sq/Ma) is preferably 0.15 or less.
Since the resolution of the human eye is about 100 μm, if there is a large variation in each 100 μm square, the human eye perceives the distortion of the transmitted light and observes it as glare. Therefore, when the ratio of Ma to Sq (Sq/Ma) exceeds 0.15, the distortion of the transmitted light of the laminate of the present invention is recognized and observed as glare. The above (Sq/Ma) is preferably 0.12 or less, more preferably 0.10 or less.
The average value (Ma) of Ra is preferably 0.10 μm or more and 0.40 μm or less. If it is less than 0.10 μm, the antiglare property of the laminate of the present invention may be insufficient, and if it exceeds 0.40 μm, the contrast of the laminate of the present invention may deteriorate.
The arithmetic mean roughness Sa is obtained by extending the arithmetic mean roughness Ra, which is a two-dimensional roughness parameter described in JIS B0601: 1994, to three dimensions, and the orthogonal coordinate axes X and Y axes are on the reference plane. , where Z(x, y) is the roughness curved surface, and Lx and Ly are the sizes of the measurement area surface.

In addition, in the above formula (a), A=Lx×Ly is represented.
If the height at the i-th point in the X-axis direction and the j-th point in the Y-axis direction is Zi,j, the arithmetic mean roughness Sa is calculated by the following formula (b).

In addition, in the above formula (b), N represents the total number of points.
Devices for obtaining such a three-dimensional arithmetic mean roughness Sa include contact surface roughness meters and non-contact surface roughness meters (for example, interference microscopes, confocal microscopes, atomic force microscopes, etc.). mentioned. Among these, it is preferable to measure using an interference microscope because of the simplicity of the measurement. Examples of such an interference microscope include the "New View" series manufactured by Zygo.

In the optical laminate of the present invention, as described above, silica fine particles and organic fine particles form unevenness on the surface of the optical layer, so that the unevenness can be made smooth. Specifically, the uneven shape of the surface of the optical layer is defined as follows: Sm is the average spacing of the unevenness on the surface of the optical layer; θa is the average inclination angle of the uneven portion; When the 10-point average roughness is Rz, only the edge part of the reflected image is not clearly visible to ensure anti-glare properties, eliminate large diffusion to prevent stray light generation, and regular transmission It is preferable to satisfy the following formula from the viewpoint of obtaining an optical layered body having a bright image and excellent contrast in a bright room and a dark room by providing an appropriate portion. If θa, Ra, and Rz are less than the lower limits, reflection of external light may not be suppressed. Also, if θa, Ra, and Rz exceed the upper limits, the brightness of the image will decrease due to the decrease in the specular transmission component, the bright room contrast will decrease due to the increase in the diffuse reflection of external light, and the stray light from the transmitted image light will increase. As a result, the darkroom contrast may be lowered. In the configuration of the present invention, if Sm is less than the lower limit, it may become difficult to control aggregation. On the other hand, if Sm exceeds the upper limit, there is a possibility that the fineness of the image cannot be reproduced, resulting in a poor quality image.
50 μm<Sm<600 μm
0.1°<θa<1.5°
0.02 μm<Ra<0.25 μm
0.30 μm<Rz<2.00 μm

Further, from the above viewpoint, the uneven shape of the optical layer more preferably satisfies the following formula.
100 μm<Sm<400 μm
0.1°<θa<1.2°
0.02 μm<Ra<0.15 μm
0.30 μm<Rz<1.20 μm
More preferably, the uneven shape of the optical layer satisfies the following formula.
120 μm<Sm<300 μm
0.1°<θa<0.5°
0.02 μm<Ra<0.12 μm
0.30 μm<Rz<0.80 μm
In this specification, the above Sm, Ra and Rz are values obtained by a method conforming to JIS B 0601-1994, and θa is a surface roughness measuring instrument: SE-3400 instruction manual (1995.07 _.20 revision) ₍ Kosaka Laboratory Co., Ltd.), and as shown in FIG. _{3 + .} ^_ _{_ _ _}
Such Sm, θa, Ra, and Rz can be obtained by measuring with, for example, a surface roughness measuring instrument: SE-3400/manufactured by Kosaka Laboratory Ltd., or the like.

The optical laminate of the present invention preferably has a total light transmittance of 85% or more. If it is less than 85%, color reproducibility and visibility may be impaired when the optical layered body of the present invention is mounted on the surface of an image display device. The total light transmittance is more preferably 90% or more, and even more preferably 91% or more.
The above total light transmittance can be measured according to JIS K7361 with "HM-150" manufactured by Murakami Color Research Laboratory Co., Ltd., or the like.

Further, the optical layered body of the present invention preferably has a total haze of less than 5.0%. The above total haze is a haze value (%) obtained by measuring the haze of the entire optical layered body according to JIS K-7136 with "HM-150" manufactured by Murakami Color Research Laboratory. The optical layer may consist of an internal haze due to internal diffusion due to fine particles contained and an external haze due to the irregular shape of the outermost surface, and the internal haze due to internal diffusion is preferably in the range of 0% or more and less than 5.0%. , more preferably 0% or more and less than 4.0%, and even more preferably 0% or more and less than 2.5%. The external haze of the outermost surface is preferably in the range of 0% or more and less than 2.0%, more preferably in the range of 0% or more and less than 1.0%. When the reflection and/or transmission has an intensity at a diffusion angle of 1.0 degrees or more and less than 2.5 degrees, the internal haze and/or external haze is most preferably 0%. If the optical layer does not have diffusion with a diffusion angle of 1.0 degree or more due to surface unevenness, the anti-glare effect cannot be seen. This is because the Here, "having an intensity at a diffusion angle of 1.0 degrees or more and less than 2.5 degrees" means that the intensity of diffused light is measured every 0.1 degrees from a diffusion angle of 0 degrees to 2.4 degrees. It means that the sum of the intensity of diffused light with a diffusion angle of 1.0 degrees to 2.4 degrees is 10% or more with respect to the sum of the time.
In the optical layered body of the present invention, by using fumed silica as the silica fine particles, the internal haze and the external haze of the optical layer can be independently controlled. For example, by using fumed silica, since the average particle size of the fumed silica is small, internal haze does not occur, and only external haze can be adjusted. The internal haze can be adjusted by controlling the ratio of the refractive index of the organic fine particles and the refractive index of the binder resin, or by impregnating the organic fine particles with the monomer of the binder resin to change the refractive index of the organic particle interface. can do.
Further, the internal haze is obtained as follows.
A resin having a refractive index equal to or less than 0.02 in refractive index with the resin forming the surface unevenness is applied to the unevenness on the surface of the optical layer of the anti-glare film with a wire bar to a dry film thickness of 8 μm (completely After drying at 70° C. for 1 minute, it is cured by irradiating ultraviolet rays of 100 mJ/cm 2 . As a result, irregularities on the surface are flattened, and a film with a flat surface is obtained. However, if a leveling agent or the like is contained in the composition for forming the optical layer having an uneven shape, and the resin applied to the surface of the optical layer is easy to repel and difficult to get wet, the surface of the optical layer may be coated in advance. is saponified (immersed in a 2 mol/L NaOH (or KOH) solution at 55 ° C for 3 minutes, washed with water, completely removed with Kimwipe (registered trademark) or the like, and then dried in an oven at 50 ° C for 1 minute. ) to make it hydrophilic.
This flattened film does not have surface irregularities, so it has only an internal haze. The internal haze can be obtained by measuring the total haze of this film in accordance with JIS K-7136 in the same manner as for the total haze.
Also, the external haze can be obtained as (total haze - internal haze).

In addition, the optical layered body of the present invention preferably has a low refractive index layer on the optical layer, because it can more preferably prevent the occurrence of white blurring.
The low refractive index layer is a layer that plays a role of lowering the reflectance when external light (for example, fluorescent light, natural light, etc.) is reflected on the surface of the optical layered body. The low refractive index layer preferably includes 1) a resin containing low refractive index particles such as silica and magnesium fluoride, 2) a fluorine-based resin that is a low refractive index resin, and 3) a fluorine containing silica or magnesium fluoride. 4) a thin film of a low refractive index substance such as silica, magnesium fluoride, or the like. As the resin other than the fluororesin, the same resin as the binder resin constituting the optical layer can be used.
In addition, the silica described above is preferably hollow silica fine particles, and such hollow silica fine particles can be produced, for example, by the production method described in Examples of JP-A-2005-099778.
These low refractive index layers preferably have a refractive index of 1.45 or less, particularly 1.42 or less.
The thickness of the low-refractive-index layer is not limited, but may be appropriately set within a range of approximately 30 nm to 1 μm.
In addition, although the effect can be obtained with a single layer of the low refractive index layer, two or more low refractive index layers may be appropriately provided for the purpose of adjusting a lower minimum reflectance or a higher minimum reflectance. . When two or more low refractive index layers are provided, it is preferable to provide a difference in refractive index and thickness of each low refractive index layer.

As the fluororesin, a polymerizable compound containing at least a fluorine atom in the molecule or a polymer thereof can be used. The polymerizable compound is not particularly limited, but preferably has a curing reactive group such as a functional group that cures with ionizing radiation or a polar group that cures with heat. A compound having these reactive groups at the same time may also be used. In contrast to this polymerizable compound, a polymer does not have any of the above reactive groups.

As the polymerizable compound having a functional group that is cured by ionizing radiation, a wide range of fluorine-containing monomers having an ethylenically unsaturated bond can be used. More specifically, fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluorobutadiene, perfluoro-2,2-dimethyl-1,3-dioxole, etc.) are exemplified. can be done. Those having a (meth)acryloyloxy group include 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3,3-pentafluoropropyl (meth)acrylate, 2-(perfluorobutyl ) ethyl (meth) acrylate, 2-(perfluorohexyl) ethyl (meth) acrylate, 2-(perfluorooctyl) ethyl (meth) acrylate, 2-(perfluorodecyl) ethyl (meth) acrylate, α-trifluoro (Meth)acrylate compounds having a fluorine atom in the molecule, such as methyl methacrylate and ethyl α-trifluoromethacrylate; There are also fluorine-containing polyfunctional (meth)acrylic acid ester compounds having a cycloalkyl group or fluoroalkylene group and at least two (meth)acryloyloxy groups.

Preferred examples of the thermosetting polar group include hydrogen bond forming groups such as hydroxyl, carboxyl, amino and epoxy groups. These are excellent not only in adhesion to coating films but also in affinity with inorganic ultrafine particles such as silica. Polymerizable compounds having a thermosetting polar group include, for example, 4-fluoroethylene-perfluoroalkyl vinyl ether copolymer; fluoroethylene-hydrocarbon-based vinyl ether copolymer; epoxy, polyurethane, cellulose, phenol, polyimide and the like. Fluorine-modified products of each resin and the like can be mentioned.
Examples of the polymerizable compound having both a functional group that cures with ionizing radiation and a polar group that cures with heat include partially and fully fluorinated alkyl, alkenyl, and aryl esters of acrylic or methacrylic acid, fully or partially fluorinated vinyl ethers, fully Alternatively, partially fluorinated vinyl esters, fully or partially fluorinated vinyl ketones, and the like can be exemplified.

Moreover, as a fluorine-type resin, the following can be mentioned, for example.
A polymer of a monomer or a monomer mixture containing at least one fluorine-containing (meth)acrylate compound of the polymerizable compound having an ionizing radiation-curable group; at least one fluorine-containing (meth)acrylate compound and methyl (meth) Copolymers with (meth)acrylate compounds containing no fluorine atom in the molecule such as acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate; fluoroethylene , vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, 3,3,3-trifluoropropylene, 1,1,2-trichloro-3,3,3-trifluoropropylene, hexafluoropropylene. homopolymers or copolymers of monomers; A silicone-containing vinylidene fluoride copolymer obtained by adding a silicone component to these copolymers can also be used. In this case, the silicone component includes (poly)dimethylsiloxane, (poly)diethylsiloxane, (poly)diphenylsiloxane, (poly)methylphenylsiloxane, alkyl-modified (poly)dimethylsiloxane, azo group-containing (poly)dimethylsiloxane, Dimethylsilicone, phenylmethylsilicone, alkyl/aralkyl-modified silicone, fluorosilicone, polyether-modified silicone, fatty acid ester-modified silicone, methyl hydrogen silicone, silanol group-containing silicone, alkoxy group-containing silicone, phenol group-containing silicone, methacrylic-modified silicone, acrylic Modified silicone, amino-modified silicone, carboxylic acid-modified silicone, carbinol-modified silicone, epoxy-modified silicone, mercapto-modified silicone, fluorine-modified silicone, polyether-modified silicone and the like are exemplified. Among them, those having a dimethylsiloxane structure are preferable.

Furthermore, non-polymers or polymers composed of the following compounds can also be used as the fluororesin. That is, a fluorine-containing compound having at least one isocyanato group in the molecule is reacted with a compound having at least one functional group that reacts with the isocyanato group such as an amino group, hydroxyl group or carboxyl group in the molecule. Compounds obtained; Compounds obtained by reacting fluorine-containing polyols such as fluorine-containing polyether polyols, fluorine-containing alkyl polyols, fluorine-containing polyester polyols, and fluorine-containing ε-caprolactone-modified polyols with compounds having isocyanato groups, etc. can be used.

Further, each binder resin as described for the optical layer can be mixed and used together with the above-described polymerizable compound or polymer having a fluorine atom. Furthermore, a curing agent for curing reactive groups and the like, and various additives and solvents for improving coatability and imparting antifouling properties can be used as appropriate.

In the formation of the low refractive index layer, the viscosity of the low refractive index layer composition to which a low refractive index agent and a resin are added is set to 0.5 to 5 mPa·s (25° C.) at which preferable coating properties can be obtained. It is preferably in the range of 0.7 to 3 mPa·s (25°C). It is possible to realize an antireflection layer excellent in visible light, to form a uniform thin film without coating unevenness, and to form a low refractive index layer having particularly excellent adhesiveness.

The means for curing the resin may be the same as that described for the optical layer described above. When a heating means is used for the curing treatment, it is preferable to add a thermal polymerization initiator to the fluororesin composition to generate, for example, radicals by heating to initiate polymerization of the polymerizable compound.

The layer thickness (nm) d _A of the low refractive index layer is expressed by the following formula (3):
d _A =mλ/(4n _A ) (3)
(In the above formula,
n _A represents the refractive index of the low refractive index layer,
m represents a positive odd number, preferably 1;
λ is the wavelength, preferably a value in the range 480-580 nm)
is preferably satisfied.

Further, in the present invention, the low refractive index layer has the following formula (4):
120<n _A d _A <145 (4)
is preferably satisfied in terms of low reflectance.

The optical layered body of the present invention may also contain other layers (antistatic layer, antifouling layer, adhesive layer, other hard coat layer, etc.) as necessary within a range that does not impair the effects of the present invention. One layer or two or more layers can be formed as appropriate. Among them, it is preferable to have at least one layer of an antistatic layer and an antifouling layer. These layers may be similar to known antireflection laminates.

The optical laminate of the present invention preferably has a contrast ratio of 80% or higher, more preferably 90% or higher. If it is less than 80%, the optical layered body of the present invention may be inferior in darkroom contrast and visibility may be impaired when the optical layered body of the present invention is mounted on the surface of a display. The contrast ratio in this specification is a value measured by the following method.
That is, as a backlight unit, a cold cathode tube light source with a diffusion plate is used, and two polarizing plates (AMN-3244TP manufactured by Samsung) are used. The value (L _max /L _min ) obtained by dividing the luminance L _max by the luminance L _min of the light that passes when set in Cross Nicol is defined as the contrast, and the contrast of the optical laminate (polyester base material + optical layer, etc.) The value obtained by dividing (L ₁ ) by the contrast (L ₂ ) of the polyester base material (L ₁ /L ₂ )×100 (%) is defined as the contrast ratio.
The above luminance measurement is performed in a dark room. A color luminance meter (BM-5A manufactured by Topcon Co., Ltd.) is used to measure the above luminance, the measurement angle of the color luminance meter is set to 1°, and the field of view on the sample is φ5 mm. In addition, the amount of light of the backlight is set so that the luminance becomes 3600 cd/m ² when two polarizing plates are set in parallel Nicols with no sample set.

The optical layered body of the present invention is produced by forming an optical layer on the optical control layer using, for example, an optical layer composition containing silica fine particles, organic fine particles, a monomer component of a binder resin, and a solvent. can do.
As for the composition for the optical layer and the method for forming the optical layer, the same materials and methods as those described as the method for forming the optical layer in the above-described optical layered body can be used.

The optical layered body of the present invention can be made into a polarizing plate by providing the optical layered body of the present invention on the surface of the polarizing element on the side opposite to the side on which the optical layer is present in the optical layered body.

The polarizing element is not particularly limited, and for example, a polyvinyl alcohol film, a polyvinyl formal film, a polyvinyl acetal film, a saponified ethylene-vinyl acetate copolymer film, etc. dyed with iodine or the like and stretched can be used. In laminating the polarizing element and the antiglare film of the present invention, it is preferable to saponify the polyester base material. The saponification treatment improves adhesion and provides an antistatic effect.

The present invention also provides an image display device comprising the optical layered body or the polarizing plate of the present invention described above.
A liquid crystal display (LCD), which is a representative example of the above, includes a transmissive display and a light source device for illuminating the transmissive display from behind. When the image display device of the present invention is an LCD, the optical laminate or polarizing plate of the present invention is formed on the surface of this transmissive display.

When the present invention is a liquid crystal display device having the optical layered body, the light source of the light source device irradiates from below the optical layered body. A retardation plate may be inserted between the liquid crystal display element and the polarizing plate. An adhesive layer may be provided between each layer of the liquid crystal display device, if necessary.

Here, in the case where the present invention is a liquid crystal display device having the optical layered body, the optical layered body is the combination of the slow axis of the optical layered body and the polarizing plate (the polarizing plate placed on the viewing side of the liquid crystal cell). By setting the angle with the absorption axis to 45°±15°, good visibility can be obtained even when the liquid crystal display device is observed through a polarizing plate such as sunglasses.
Further, when the present invention is a liquid crystal display device having the optical layered body, the optical layered body has the slow axis of the optical layered body and the absorption of the polarizing plate (the polarizing plate arranged on the viewing side of the liquid crystal cell). More preferably, the angle formed with the axis is 0°±30° or 90°±30°. When the angle formed by the slow axis of the optical layered body and the absorption axis of the polarizing plate is within the above range, it is possible to extremely highly suppress the occurrence of rainbow unevenness in the displayed image of the liquid crystal display device of the present invention. . Although the reason for this is not clear, it is considered to be due to the following reasons.
That is, in an environment without external light or fluorescent light (hereinafter, such an environment is also referred to as a “dark place”), the slow axis of the optical laminate of the liquid crystal display device of the present invention and the absorption of the polarizing plate The occurrence of rainbow spots can be suppressed regardless of the angle formed with the axis. However, in an environment with external light or fluorescent light (hereinafter referred to as "bright place"), external light or fluorescent light has a continuous broad spectrum. Therefore, unless the angle formed by the slow axis of the optical layered body and the absorption axis of the polarizing plate is within the above range, rainbow-like unevenness occurs and the display quality deteriorates.
Furthermore, since the backlight transmitted through the color filter does not always have a continuous broad spectrum, the angle formed by the slow axis of the optical laminate and the absorption axis of the polarizing plate must be within the above range. , it is speculated that the display quality is degraded due to the occurrence of rainbow unevenness.

In the liquid crystal display device of the present invention, the backlight source is not particularly limited, but is preferably a white light emitting diode (white LED).
The above-mentioned white LED is an element that emits white light by combining a light-emitting diode that uses a compound semiconductor and emits blue light or ultraviolet light with a phosphor. In particular, white light emitting diodes, which are composed of light emitting elements that combine blue light emitting diodes using compound semiconductors and yttrium-aluminum-garnet-based yellow phosphors, have a continuous and broad emission spectrum, and thus improve hazing. It is suitable for the above-mentioned backlight source in the present invention because it is effective for light emission and has excellent luminous efficiency. In addition, since white LEDs with low power consumption can be widely used, it is possible to achieve the effect of saving energy.

The plasma display (PDP), which is the image display device, includes a front glass substrate (electrodes are formed on the surface) and a back glass substrate (electrodes and micro-grooves are formed on the surface, and red, green and blue phosphor layers are formed in the grooves). When the image display device of the present invention is a PDP, it is also provided with the optical laminate described above on the surface of the surface glass substrate or its front plate (glass substrate or film substrate).

The above image display device is an ELD device that displays by vapor-depositing zinc sulfide or a diamine substance: a luminescent material on a glass substrate and controlling the voltage applied to the substrate, or an electric signal is converted into light. Alternatively, it may be a CRT or the like that generates an image visible to the human eye. In this case, the optical layered body of the present invention is provided on the surface of each image display device as described above or on the surface of the front plate thereof.
Moreover, the optical layered body of the present invention can also be suitably used for the image display surface of a touch panel.

Since the optical layered body of the present invention has the structure described above, it is possible to suppress the occurrence of glare, and to have excellent brightness and prevent deterioration of contrast.
Therefore, the optical laminate of the present invention can be used for image display in image display devices such as liquid crystal display devices (LCD), plasma displays (PDP), organic/inorganic electroluminescence displays (LED), electronic paper, ELD, CRT, and touch panels. It can be used suitably for the surface.

FIG. 2 is a cross-sectional view schematically showing part of the optical control layer in the optical layered body of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows typically an example of the optical laminated body of this invention. FIG. 4 is a perspective view schematically showing another example of the optical layered body of the present invention; It is explanatory drawing of the measuring method of (theta)a. 4 is a cross-sectional micrograph of an optical control layer according to an example. (a) to (d) are explanatory diagrams of the activation energy irradiation step. It is explanatory drawing of an activation energy irradiation process.

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited only to these examples and comparative examples.
In the text, "parts" and "%" are based on mass unless otherwise specified.

(Example 1)
(Composition for optical control layer 1)
High refractive index resin (fluor orange acrylate, refractive index: 1.62 50 parts by mass) Low refractive index resin (polypropylene glycol diacrylate, refractive index: 1.45)
50 parts by mass Photopolymerization initiator (1-hydroxy-cyclohexyl-phenyl-ketone) 4 parts by mass

(Production of optical control layer 1)
A composition for the optical control layer 1 having the above composition was prepared and coated on a light-transmitting PET substrate having a thickness of 100 μm so that the film thickness after curing was 100 μm to form a coating film. Then, a light-transmitting PET substrate having a thickness of 100 μm was laminated on the coating film.
Parallel UV rays were irradiated perpendicularly to the coating film surface from above the light-transmitting PET substrate at 5 mW/cm ² for 30 seconds. An optical control layer 1 was obtained by peeling the PET on both sides from the coating film. When a cross section of the optical control layer 1 cut along a plane perpendicular to the film surface was observed with an optical microscope, as shown in FIG. 5, a columnar structure continuous from one surface to the other surface was formed. Observation of the cross section was performed before peeling off the PET on both sides.

(Optical layer composition 1)
Pentaerythritol triacrylate 38 parts by mass Isocyanuric acid EO-modified triacrylate 22 parts by mass Photopolymerization initiator (1-hydroxy-cyclohexyl-phenyl-ketone) 5 parts by mass Silicone-based leveling agent 0.1 parts by mass Translucent particles (spherical poly Acrylic-styrene copolymer; average particle diameter 3.5 μm, refractive index 1.525) 12 parts by mass Inorganic ultrafine particles (silica with reactive functional groups introduced on the surface, solvent MIBK, solid content 30%, average primary particles Diameter 12 nm) 120 parts by mass Solvent (toluene) 135 parts by mass

(Production of optical layer 1)
Optical layer composition 1 having the above composition was prepared, and as a transparent substrate layer, the optical layer composition 1 was coated on a TAC substrate having a thickness of 80 μm so that the film thickness after curing was 5 μm. After drying for 60 seconds in an oven at 120° C., non-parallel ultraviolet rays were irradiated so that the irradiation amount was 120 mJ/cm ² to cure the coating film, thereby obtaining an optical layer 1 having an uneven surface.

An optical layered body according to Example 1 was manufactured by adhering the optical control layer 1 to the surface of the transparent substrate layer opposite to the surface on which the optical layer 1 was formed via a transparent adhesive.

(Example 2)
(Production of optical control layer 2)
An optical control layer 2 was produced in the same manner as the optical control layer 1, except that the film thickness after curing was set to 200 μm.
An optical laminate according to Example 2 was produced in the same manner as in Example 1, except that the optical control layer 2 was used instead of the optical control layer 1 .

(Comparative example 1)
(Composition for optical control layer 3)
Pentaerythritol triacrylate 100 parts by mass Photopolymerization initiator (1-hydroxy-cyclohexyl-phenyl-ketone) 3 parts by mass Silicone leveling agent 0.1 parts by mass Translucent particles (spherical melamine particles, average particle size 1.2 μm, Refractive index 1.66) 7.5 parts by mass Solvent (toluene) 130 parts by mass

(Production of optical control layer 3)
A composition for the optical control layer 3 having the above composition was prepared, and the composition for the optical control layer 3 was coated on a TAC substrate having a thickness of 80 μm as a light-transmitting substrate so that the film thickness after curing was 20 μm. After drying the coating film in an oven at 70 ° C. for 60 seconds, the coating film is cured by irradiating non-parallel ultraviolet rays so that the irradiation amount is 120 mJ / cm ² . A control layer 3 (diffusion film) was obtained.

An optical laminate according to Comparative Example 1 was prepared in the same manner as in Example 1, except that the optical control layer 3 was bonded via a transparent adhesive to the surface of the optical layer 1 opposite to the surface on which the uneven shape was formed. body.

(Comparative example 2)
(Composition for optical layer 2)
Pentaerythritol triacrylate 90 parts by mass Acrylic polymer (molecular weight 75,000) 10 parts by mass Photopolymerization initiator (1-hydroxy-cyclohexyl-phenyl-ketone) 3 parts by mass Silicone leveling agent 0.1 parts by mass Translucent particles ( Spherical polystyrene particles; particle size 3.5 μm, refractive index 1.59) 12 parts by mass Solvent 1 (toluene) 145 parts by mass Solvent 2 (cyclohexanone) 60 parts by mass

(Production of optical layer 2)
An optical layer composition 2 having the above composition was prepared and coated on a TAC substrate having a thickness of 80 μm as a light-transmitting substrate so that the optical layer composition 2 was cured to a thickness of 4.5 μm. After drying for 60 seconds in an oven at 70° C., non-parallel ultraviolet light is irradiated so that the irradiation amount is 120 mJ/cm ² to cure the coating film, thereby obtaining an optical layer 2 having an uneven surface. rice field.
An optical layered body according to Comparative Example 2 was obtained by forming the optical layer 2 on the obtained TAC base material.

The optical layered bodies obtained in Examples and Comparative Examples were evaluated as follows. Table 1 shows the results.

(glare)
In each of the optical layered bodies obtained in Examples and Comparative Examples, the surface on which the optical layer of the optical layered body is not formed and the glass surface on which the black matrix (glass thickness: 0.7 mm) corresponding to 350 ppi is not formed. were pasted together with a transparent adhesive to prepare a sample.
A white surface light source (LIGHTBOX manufactured by HAKUBA, average luminance 1000 cd/m ² ) was installed on the black matrix side of the thus obtained sample to generate pseudo glare.
This was photographed from the optical laminate side with a CCD camera (KP-M1, C-mount adapter, close-up ring; PK-11A Nikon, camera lens; 50 mm, F1.4s NIKKOR). The distance between the CCD camera and the optical layered body was set to 250 mm, and the focus of the CCD camera was adjusted to match the optical layered body. Images taken with a CCD camera were loaded into a personal computer and analyzed as follows using image processing software (ImagePro Plus ver. 6.2; manufactured by Media Cybernetics).

First, an evaluation point of 200×160 pixels was selected from the captured image, and the evaluation point was converted to 16-bit gray scale. Next, a low-pass filter was selected from the emphasis tab of the filter command, and the filter was applied under the conditions of "3 x 3, number of times: 3, strength: 10". This removed the component derived from the black matrix pattern.
Next, flattening was selected, and shading correction was performed under the conditions of "background: dark, object width 10".
Next, the contrast was enhanced with the contrast enhancement command "contrast: 96, brightness: 48".
The resulting image was converted to 8-bit grayscale, and the variation in value for each pixel of 150×110 pixels was calculated as the standard deviation value to quantify glare. It can be said that the smaller the digitized glare value, the less the glare.

(contrast ratio)
In the measurement of the contrast ratio, a cold cathode tube light source with a diffusion plate was used as a backlight unit, two polarizing plates (AMN-3244TP manufactured by Samsung) were used, and the polarizing plates were set in parallel Nicols. By dividing L _max of the luminance of light passing through the cross Nicol by L _min of the luminance of light passing when installed in Cross Nicol, the optical laminate according to the example and the comparative example when placed on the outermost surface Obtain the contrast (L ₁ ) and the contrast (L ₂ ) when only the light-transmitting substrate is placed on the outermost surface, and calculate the contrast ratio by calculating (L ₁ /L ₂ ) × 100 (%) was calculated.
The luminance was measured using a color luminance meter (BM-5A manufactured by Topcon Co., Ltd.) under a darkroom environment with an illuminance of 5 Lx or less. The measurement angle of the color luminance meter was set to 1°, and the measurement was performed with a field of view of φ5 mm from the vertical direction on the sample. The amount of light of the backlight was set so that the luminance would be 3600 cd/m ² when two polarizing plates were set in parallel Nicols without any sample.

(transmitted light intensity)
The transmitted light intensity of each optical laminate obtained in Examples and Comparative Examples was measured as follows.
Using a variable angle photometer (GC-5000L, manufactured by Nippon Denshoku Industries Co., Ltd.), set the light source angle to 0 degrees and the sensitivity setting to 1000 times in transmission measurement, and the side opposite to the surface on which the optical layer is formed. The surface of the sample is set on the light source side, and the intensity of the transmitted light of the optical laminate is scanned with the light receiver in the range of -40 degrees to +40 degrees, ±5 degrees, ±10 degrees, ±20 degrees, and Light intensity was measured at ±40 degrees. Then, the average of the light intensity value at +5 degrees and the light intensity value at -5 degrees was taken as the light intensity at 5 degrees. Similar calculations were made for 10 degrees, 20 degrees, and 40 degrees. Then, T5/T10 and T20/T40 were calculated. The value of the light intensity is a relative value when the light intensity at 0 degrees when no sample is installed is 100000.

The optical layered bodies according to the examples had an optical control layer in which a columnar structure was continuously formed from one surface to the other surface, so that glare was small and the contrast ratio was excellent. On the other hand, in the optical laminate according to Comparative Example 1, the optical control layer did not have a continuous columnar structure from one surface to the other surface, and translucent fine particles were dispersed in the resin component. Also, the optical layered body according to Comparative Example 2 was not provided with an optical control layer. All of the comparative examples had light diffusing properties due to conventional particles, and thus were inferior to the optical layered bodies according to the examples in terms of glare and contrast ratio.

The optical layered body of the present invention can suppress the occurrence of glare, has excellent luminance, and can prevent a decrease in contrast.

10, 20, 30 optical control layers 11, 21, 31 low refractive index regions 12, 22, 32 high refractive index region 50 irradiation light 60 parallel light 101 coating layer 102 process sheet 125 linear light source 202 point light source 204 lens 200 (200a , 200b) Irradiation light collimating member 210 Light shielding member 210a Plate member 210b Cylindrical member

Claims (2)

An optical laminate having an optical control layer and an optical layer having an uneven surface,
The optical control layer has a low refractive index region and a high refractive index region having a higher refractive index than the low refractive index region,
The low refractive index region and the high refractive index region are provided in a columnar shape continuously from one surface to the other surface of the optical control layer,
When light is incident from the normal direction of one surface of the optical control layer and the transmitted light intensity is measured, the transmitted light intensity at a diffusion angle of 5° is T5, the transmitted light intensity at a diffusion angle of 10° is T10, and the diffusion When the transmitted light intensity at an angle of 20° is T20 and the transmitted light intensity at a diffusion angle of 40° is T40, the following formulas (1) and (2) are satisfied,
The low refractive index region has a refractive index of 1.40 to 1.50, the high refractive index region has a refractive index of 1.50 to 1.65,
The shortest distance between the adjacent low refractive index regions and/or the shortest distance between the adjacent high refractive index regions is 0.1 at the optical layer side interface or the interface opposite to the optical layer side of the optical control layer. ~15 μm,
In the optical layer having an uneven shape on the surface, the average spacing of the unevenness on the surface is Sm, the average inclination angle of the unevenness is θa, the arithmetic average roughness of the unevenness is Ra, and the ten-point average roughness of the unevenness is Rz. 50 μm<Sm<600 μm that satisfies the following formula
0.1°<θa<1.5°
0.02 μm<Ra<0.25 μm
0.30 μm<Rz<2.00 μm
An optical layered body characterized by:
T5/T10≦5 (1)
T20/T40≧50 (2) An image display device comprising the optical layered body according to claim 1 .

Images