KR20220084269A - Polarizing plate having a light diffusing film and a light diffusing film - Google Patents

Abstract

Provided is a light-diffusing film that can contribute to durability (particularly, humidity durability) of the optical laminate when combined with other films to form an optical laminate. The light-diffusion film of the present invention includes a shaping layer and a light diffusion layer disposed on one side of the shaping layer, wherein the shaping layer includes a base portion and an uneven portion disposed on one surface of the base portion, and the light diffusion layer includes the shaping It is disposed on the side of the base portion of the layer.

Description

Polarizing plate having a light diffusing film and a light diffusing film

The present invention relates to a light diffusing film and a polarizing plate including the light diffusing film.

In recent years, the demand for ultra-thinning of image display apparatuses (for example, liquid crystal display device, organic electroluminescent display apparatus) and improvement of designability (for example, slim bezel formation) is becoming very strong. In connection with this, the demand for the integration of the optical member and/or optical film used for an image display apparatus and/or integration of a function is also strong. As an example of such integration or integration of functions, it has been proposed to provide a light-diffusion function by directly bonding a light-diffusion film to a predetermined optical member or the like. Although excellent optical properties and workability, and durability (particularly, humidity durability) of an optical laminate including the light-diffusion film are sometimes required for a light-diffusing film, in a light-diffusion film used by direct bonding, these characteristics are It is difficult to satisfy with a good balance. In particular, it was difficult to stably produce a light-diffusion film composed of light-diffusing particles, such as frequent breakage during film forming, and it was difficult to achieve both workability and other properties (eg, optical properties).

Japanese Patent Laid-Open No. 2012-118235 Japanese Patent Laid-Open No. 2009-025774

The present invention has been made in order to solve the above conventional problems, and its main object is to have excellent workability and optical properties, and to provide durability (especially, It is to provide a light-diffusion film which can contribute to humidification durability).

The light-diffusion film of the present invention includes a shaping layer and a light diffusion layer disposed on one side of the shaping layer, wherein the shaping layer includes a base portion and an uneven portion disposed on one surface of the base portion, and the light diffusion layer includes the shaping It is disposed on the side of the base portion of the layer.

In one embodiment, the said light-diffusion layer and the said shaping|molding layer are laminated|stacked via an adhesive layer or an adhesive bond layer.

In one embodiment, the said light-diffusion layer is formed directly in the said shaping|shaping layer.

In one embodiment, the said light-diffusion layer contains light-diffusion particle|grains, and the volume average particle diameter of the said light-diffusion microparticles|fine-particles is 2 micrometers - 30 micrometers or less.

In one embodiment, the said light-diffusion film is 30 % - 95 % of haze values.

According to another aspect of the present invention, a polarizing plate is applied. This polarizing plate is provided with a polarizer and the said light-diffusion film laminated|stacked through the said polarizer and an adhesive layer.

According to the present invention, by providing a shaping layer and a light diffusion layer having an uneven portion, excellent processability and optical properties are obtained, and when an optical laminate is formed in combination with another film, the durability (particularly, humidification) of the optical laminate is obtained. durability) may be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing of the light-diffusion film by one Embodiment of this invention.
It is a schematic plan view which shows the representative example of the shape at the time of planar view of the convex part of the uneven|corrugated surface in the light-diffusion film by embodiment of this invention.
It is a schematic sectional drawing of the optical laminated body by one Embodiment of this invention.
4 is a schematic cross-sectional view of a polarizing plate according to one embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, although embodiment of this invention is described with reference to drawings, this invention is not limited to these embodiment. In addition, the drawings are schematically shown for easy viewing, and the ratios of length, width, and thickness, and the shape and detail of concavities and convexities are different from the actual ones.

A. Light diffusing film

A-1. full configuration

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing of the light-diffusion film by one Embodiment of this invention. The light-diffusion film 100 of the illustrated example includes a shaping layer 10 and a light-diffusion layer 20 disposed on one side of the shaping layer 10 . The shaping layer 10 has a base portion 11 and an uneven portion 12 formed on one side of the base portion 11 . The uneven portion 12 has a convex portion 12a and a concave portion 12b. The light diffusion layer 20 is disposed on the base portion 11 side of the shaping layer 10 (the opposite side to the uneven portion 12 ). In one embodiment, the light-diffusion film of this invention adhere|attaches the uneven|corrugated part 12 to another film, and is used.

Fig. 2 is a schematic plan view showing a representative example of a shape in a plan view of a convex portion of an uneven portion in a shaping layer of a light-diffusion film according to an embodiment of the present invention. In one embodiment, as shown in FIG. 2 , the concave portion 12b may have a cell structure formed by being surrounded by the convex portion 12a (substantially, a wall surface of the convex portion). By forming the concave portion having a cell structure, when a light-diffusion film is laminated on another film to constitute an optical laminate, moisture intrusion into the optical laminate can be prevented. Moreover, by forming the recessed part which has a cell structure, defects, such as a crack and a flaw, can be prevented in a cut part, and the light-diffusion film which can cut with good workability can be obtained. In addition, it is not necessary that all of the recesses have a cell structure, and, for example, in the vicinity of the edge of the light-diffusion film, the recesses may be opened toward the edge of the light-diffusion film.

Any suitable shape may be adopted for the planar view shape of the convex portion 12a in the concave-convex portion. The planar shape of the convex portion 12a may be, for example, a shape having regularity (eg, a lattice shape) or an irregular shape, as shown in FIG. 2 . The pitch of the convex portions (the distance between the convex portions and the convex portions) is preferably 1000 µm or less, more preferably 500 µm or less, and still more preferably 100 µm or less. When the planar shape of the convex portion has regularity, a bias may be formed at an angle of 1 degree to 90 degrees. When the planar shape of the convex portion is irregular, the pitch means an average pitch, and it is preferable that the distribution be 50% or more within ±50% of the average value of the pitch. With such a configuration, when the light-diffusion film is laminated on another film, the adhesive strength between the light-diffusion film and the other film can be secured, and good display quality can be secured. Moreover, when a light-diffusion film is laminated|stacked on another film and an optical laminated body is comprised, moisture penetration into the said optical laminated body can be prevented.

In the present invention, when an optical laminate is formed by laminating a light-diffusion film on another film by providing a shaping layer having an uneven portion, only the convex portion of the light-diffusion film (substantially the upper portion of the convex portion) is applied to the other film. can be glued. In addition, in this specification, adhesion|attachment of only a convex part may be called "adhesive adhesion" for convenience. By such adhesive adhesion, a substantially low refractive index part is defined by a recessed part (air part or a void part) in the vicinity of a sticking part. As a result, while realizing favorable light-diffusion performance, a luminance viewing angle can be enlarged. Conventionally, in an image display device, another film (eg, a polarizer (polarizing plate)) and a light-diffusing film are separated from each other, and as a result, an air layer is interposed between the polarizing plate and the light-diffusing film. The air layer is an obstacle to thinning, while the luminance and viewing angle is maintained large by retroreflection by the air layer. Integration of the light diffusion film with other films can realize ultra-thin and function integration, but the luminance viewing angle becomes small by the exclusion of the air layer. By forming the low-refractive-index portion in the vicinity of the adhesive portion, light is retroreflected efficiently as in the case where an air layer is present. Therefore, according to embodiment of this invention, while exhibiting desired light-diffusion performance by forming adhesive bonding, a brightness|luminance viewing angle can be maintained large (wide).

In one embodiment, the shaping layer does not contain light diffusing particles. The shaping layer can be produced by any suitable film forming method, but the shaping layer configured without the light diffusing particles is less likely to break during film forming and has excellent workability. It is one of the achievements of the present invention that the shape layer does not contain light-diffusing particles (that is, while having good workability), and can achieve good light-diffusion performance and increase the luminance viewing angle.

The thickness of the light-diffusion film of this invention becomes like this. Preferably they are 25 micrometers - 250 micrometers, More preferably, they are 30 micrometers - 100 micrometers.

The haze value of the light-diffusion film of the present invention is preferably 30% to 95%, more preferably 40% to 93%, still more preferably 60% to 90%. ADVANTAGE OF THE INVENTION According to this invention, the light-diffusion film which can implement|achieve the outstanding brightness|luminance viewing angle, suppressing a brightness|luminance fall, making a haze value high can be provided.

A-2. excipient layer

Any suitable resin may be employed as the resin constituting the shaping layer. Specific examples of the resin constituting the shaping layer include (meth)acrylic resins, polyester resins (eg, polyethylene terephthalate (PET)), cycloolefin resins (eg norbornene resins), and cellulose resins (eg, polyethylene terephthalate (PET)). For example, triacetyl cellulose (TAC)), polyvinyl alcohol-based resin, polycarbonate-based resin, polyamide-based resin, polyimide-based resin, polyethersulfone-based resin, polysulfone-based resin, polystyrene-based resin, polyolefin-based resin, Acetate-type resin is mentioned. These resins may be used independently and may use 2 or more types together. From a viewpoint of an optical characteristic, transparency, and versatility, (meth)acrylic-type resin, polyester-type resin, and cycloolefin-type resin are preferable, and (meth)acrylic-type resin is more preferable. In addition, in this specification, "(meth)acryl" means acryl and/or methacryl.

Any suitable (meth)acrylic resin may be employed as the (meth)acrylic resin. In addition, for the simplification of a base material, hereafter (meth)acrylic-type resin is only called an acryl-type resin. The acrylic resin typically contains, as a monomer unit, an alkyl (meth)acrylate as a main component. Examples of the alkyl (meth)acrylate constituting the main skeleton of the acrylic resin include a linear or branched alkyl group having 1 to 18 carbon atoms. These may be used alone or in combination. In addition, you may introduce|transduce arbitrary appropriate copolymerization monomers into acrylic resin by copolymerization. The type, number, copolymerization ratio, etc. of these copolymerization monomers may be appropriately set according to the purpose. The structural component (monomer unit) of the main skeleton of an acrylic resin is mentioned later, referring General formula (2).

The acrylic resin may have at least one preferably selected from a glutarimide unit, a lactone ring unit, a maleic anhydride unit, a maleimide unit, and a glutaric anhydride unit. Acrylic resin which has a lactone ring unit is described, for example in Unexamined-Japanese-Patent No. 2008-181078, description of this publication is taken in here as a reference. The glutarimide unit is preferably represented by the following general formula (1):

In the general formula (1), R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ³ is an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or a cycloalkyl group having 6 to 6 carbon atoms. 10 aryl groups are shown. In general formula (1), Preferably, R< ¹ > and R< ² > are each independently hydrogen or a methyl group, and R< ³ > is hydrogen, a methyl group, a butyl group, or a cyclohexyl group. More preferably, R ¹ is a methyl group, R ² is hydrogen, and R ³ is a methyl group.

The alkyl (meth)acrylate is typically represented by the following general formula (2):

In the general formula (2), R ⁴ represents a hydrogen atom or a methyl group, and R ⁵ represents a hydrogen atom or an optionally substituted aliphatic or alicyclic hydrocarbon group having 1 to 6 carbon atoms. As a substituent, halogen and a hydroxyl group are mentioned, for example. Specific examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, (meth)acrylic acid n-propyl, (meth)acrylate n-butyl, (meth)acrylate t-butyl, (meth)acrylic acid n -Hexyl, (meth)acrylic acid cyclohexyl, (meth)acrylic acid chloromethyl, (meth)acrylic acid 2-chloroethyl, (meth)acrylic acid 2-hydroxyethyl, (meth)acrylic acid 3-hydroxypropyl, (meth)acrylic acid 2,3,4,5,6-pentahydroxyhexyl and (meth)acrylic acid 2,3,4,5-tetrahydroxypentyl are mentioned. In the general formula (2), R ⁵ is preferably a hydrogen atom or a methyl group. Accordingly, particularly preferred alkyl (meth)acrylates are methyl acrylate or methyl methacrylate.

The said acrylic resin may contain only a single glutarimide unit, and may contain the some glutarimide unit from which R< ¹ >, R< ² > and R< ³ > in the said General formula (1) differs.

Preferably the content rate of the glutarimide unit in the said acrylic resin is 2 mol% - 50 mol%, More preferably, it is 2 mol% - 45 mol%, More preferably, it is 2 mol% - 40 mol%, Especially Preferably it is 2 mol% - 35 mol%, Most preferably, it is 3 mol% - 30 mol%. When the content ratio is less than 2 mol%, there is a possibility that the effect derived from the glutarimide unit (eg, high optical properties, high mechanical strength, thinning) may not be sufficiently exhibited. When the content ratio exceeds 50 mol%, for example, there is a possibility that heat resistance and transparency may become insufficient.

The said acrylic resin may contain only a single alkyl (meth)acrylate unit, and may contain the some alkyl (meth)acrylate unit from which R< ⁴ > and R< ⁵ > in the said General formula (2) differ.

Preferably the content rate of the alkyl (meth)acrylate unit in the said acrylic resin is 50 mol% - 98 mol%, More preferably, it is 55 mol% - 98 mol%, More preferably, it is 60 mol% - 98 mol% %, particularly preferably from 65 mol% to 98 mol%, most preferably from 70 mol% to 97 mol%. When the content rate is less than 50 mol%, there is a fear that the effect (eg, high heat resistance, high transparency) derived from the alkyl (meth)acrylate unit cannot be sufficiently exhibited. When the content is more than 98 mol%, the resin is brittle and brittle, high mechanical strength cannot be sufficiently exhibited, and there is a fear that productivity is deteriorated.

The acrylic resin may contain units other than glutarimide units and alkyl (meth)acrylate units.

In one embodiment, the acrylic resin may contain, for example, 0% by weight to 10% by weight of an unsaturated carboxylic acid unit not involved in an intramolecular imidization reaction described later. The content of the unsaturated carboxylic acid unit is preferably 0% by weight to 5% by weight, more preferably 0% by weight to 1% by weight. Transparency, retention stability, and moisture resistance can be maintained as content is such a range.

In one embodiment, the acrylic resin may contain copolymerizable vinylic monomer units (other vinylic monomeric units) other than the above. Examples of other vinyl monomers include acrylonitrile, methacrylonitrile, ethacrylonitrile, allylglycidyl ether, maleic anhydride, itaconic anhydride, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, aminoethyl acrylate, propylaminoethyl acrylate, dimethylaminoethyl methacrylate, ethylaminopropyl methacrylate, cyclohexylaminoethyl methacrylate, N-vinyldiethylamine, N-acetylvinylamine , allylamine, metaallylamine, N-methylallylamine, 2-isopropenyl-oxazoline, 2-vinyl-oxazoline, 2-acroyl-oxazoline, N-phenylmaleimide, phenylaminoethyl methacrylate , styrene, α-methylstyrene, p-glycidylstyrene, p-aminostyrene, 2-styryl-oxazoline, and the like. These may be used independently and may be used together. Preferably, they are styrene-type monomers, such as styrene and (alpha)-methylstyrene. The content of the other vinyl-based monomer units is preferably 0 to 1% by weight, more preferably 0 to 0.1% by weight. If it is such a range, expression of an undesired phase difference and the fall of transparency can be suppressed.

Preferably the imidation rate in the said acrylic resin is 2.5 % - 20.0 %. When the imidization ratio is within this range, a resin excellent in heat resistance, transparency, and moldability can be obtained, and occurrence of scorching during film molding or a decrease in mechanical strength can be prevented. In the said acrylic resin, the imidation rate is expressed by the ratio of a glutarimide unit and an alkyl (meth)acrylate unit. This ratio can be obtained from, for example, an NMR spectrum, an IR spectrum, etc. of an acrylic resin. In this embodiment, the imidation rate can be calculated|required by ¹ H-NMR measurement of resin using ¹ HNMR BRUKER Avance III (400 MHz). More specifically, let A be the area of the peak derived from the O-CH ₃ proton of the alkyl (meth)acrylate in the vicinity of 3.5 to 3.8 ppm, and the peak derived from the N-CH ₃ proton of glutarimide in the vicinity of 3.0 to 3.3 ppm. Let B be the area of , and it is obtained by the following equation.

Imidization rate Im(%) = {B/(A+B)}×100

The acrylic resin has a Tg (glass transition temperature) of preferably 110° C. or higher, more preferably 115° C. or higher, still more preferably 120° C. or higher, particularly preferably 125° C. or higher, and most preferably 130° C. or higher. . When Tg is 110 degreeC or more, the polarizing plate containing the light-diffusion film obtained from such resin tends to be excellent in durability. The upper limit of Tg is preferably 300°C or lower, more preferably 290°C or lower, still more preferably 285°C or lower, particularly preferably 200°C or lower, and most preferably 160°C or lower. When the Tg is within this range, the moldability may be excellent.

The said acrylic resin can be manufactured, for example by the following method. This method (I) copolymerizes an alkyl (meth) acrylate monomer corresponding to the alkyl (meth) acrylate unit represented by the general formula (2), an unsaturated carboxylic acid monomer and/or its precursor monomer to obtain a copolymer ( a) to obtain; and (II) treating the copolymer (a) with an imidizing agent, whereby intramolecular imposition of the alkyl (meth)acrylate monomer unit and the unsaturated carboxylic acid monomer and/or its precursor monomer unit in the copolymer (a) and introducing a glutarimide unit represented by the general formula (1) into the copolymer by performing a deoxidation reaction.

About the detail of the said acrylic resin and its manufacturing method, it describes in Unexamined-Japanese-Patent No. 2018-155812 and Unexamined-Japanese-Patent No. 2018-155813, for example. The descriptions of these publications are incorporated herein by reference.

The height H of the convex portion 12a is preferably 5% to 40% with respect to the thickness of the shaping layer. If it is such a range, favorable adhesive bonding can be implement|achieved. Moreover, it is advantageous also from a viewpoint of mechanical strength to make the height of a convex part into the said range, and by this, the shape of a recessed part is maintained suitably, and the outstanding light diffusivity and luminance viewing angle can be obtained.

The height H of the convex portion 12a is more preferably 10% to 30%, and still more preferably 10% to 20% with respect to the thickness of the shaping layer. If it is such a range, favorable adhesive bonding can be implement|achieved.

The height H of the convex portion 12a is preferably 2.5 µm to 25 µm, and more preferably 5 µm to 20 µm. If it is such a range, favorable adhesive bonding can be implement|achieved.

The average area of the recesses having a cell structure is preferably 5000 µm ² or more. If it is such a range, the light-diffusion film which can implement|achieve the outstanding brightness|luminance viewing angle can be obtained, suppressing a brightness|luminance fall. The average area of the recesses having a cell structure is more preferably 5000 µm ² to 50000 µm ² , still more preferably 7000 µm ² to 40000 µm ² , and particularly preferably 8000 µm ² to 30000 µm ² . If it is such a range, the said effect becomes remarkable and the light-diffusion film excellent in mechanical strength can be obtained. The average area of the recesses having a cell structure can be obtained using image analysis software (free software "ImageJ"). That is, the inside and outside of a recessed part are determined by the threshold value of the binary image of the shaping|molding film surface, and the outer frame of a recessed part is specified. It can be calculated|required by calculating the area in the specified frame, and calculating the average value of the calculated area.

In one embodiment, the maximum length in plan view of the concave portion serving as the cell structure is preferably 300 µm or more, more preferably 400 µm or more, and still more preferably 500 µm or more. Within this range, even when the light-diffusion film is cut and used, the light-diffusion film can effectively prevent moisture intrusion and improve durability near the end of the optical laminate. The maximum length of the concave portion serving as the cell structure means the corresponding distance at the location where the distance between the wall surfaces of the convex portions forming the concave portion is the longest.

The area ratio of the concave portion to the total area of the uneven portion in a planar view is preferably 50% or more, preferably 60% or more, and more preferably 70% or more. The upper limit of the area ratio of the concave portion may be, for example, 90%. When the area ratio of the concave portion is within this range, good diffusion performance is imparted to the light-diffusion film while keeping the luminance viewing angle wide, and adhesive strength can be secured when the light-diffusion film is laminated on another film.

In the light-diffusion film of the present invention, it is preferable that the wall surface of the convex portion 12a is present in a region within 500 µm from the edge of the light-diffusion film. In this invention, when the convex part 12a laminates|stacks a light-diffusion film on another film and comprises an optical laminated body, it can prevent moisture penetration into the said optical laminated body. By forming the wall surface of the convex portion 12a in a region within 500 µm from the edge of the light-diffusion film, moisture intrusion can be effectively prevented and durability near the edge of the optical laminate can be improved. It is more preferable that the wall surface of the convex portion 12a is present in a region within 400 μm from the edge of the light-diffusion film, and the wall surface of the convex portion 12a is present in a region within 300 μm from the edge of the light-diffusion film. more preferably. Preferably, the wall surface of the convex portion 12a is present in all regions within 500 µm (preferably within 400 µm, more preferably within 300 µm) from the edge of the light-diffusing film.

The ratio (B/A) of the cross-sectional area (B) of the concave portion to the cross-sectional area (A) of the entire concave-convex portion is preferably 50% or more, more preferably more than 50%, and still more preferably 60% or more. , particularly preferably 70% or more. The upper limit of the ratio (B/A) may be, for example, 90%. When the ratio (B/A) is within this range, good diffusion performance is imparted to the light-diffusion film while keeping the luminance viewing angle wide, and adhesive strength can be secured when the light-diffusion film is laminated to another film. In addition, the cross-sectional area (A) of the entire uneven portion is the area of the portion surrounded by the line connecting the surface of the convex portion, the line connecting the bottom of the concave portion, and the vertical line at both ends of the film (for reference, the outside of the portion is surrounded by a broken line 1), the cross-sectional area B of the concave portion is the cross-sectional area of each concave portion 22 (the line connecting the line of the wall of the adjacent convex portion and the surface of the convex portion and the line connecting the bottom of the concave portion) area) is the sum of

The thickness of the shaping layer is preferably 25 µm to 250 µm, and more preferably 40 µm to 100 µm.

The thickness of the base portion is preferably 22.5 μm to 225 μm, and more preferably 30 μm to 90 μm.

The concavo-convex portion (concave-convex shape) may be formed by any suitable method. The concavo-convex shape can be formed by, for example, a roughening method or a method of imparting concavities and convexities with fine particles. Specific examples of the roughening system include embossing and sandblasting. The concave-convex portion (concave-convex shape) can be typically formed by shaping the surface of the melt-extruded film with an embossing roll.

In one embodiment, a base material part and an uneven|corrugated part are comprised from the same material. Preferably, the base part and the uneven|corrugated part are integrally comprised by the same material.

A-3. light diffusion layer

The light-diffusion layer may be comprised of a light-diffusion element, and may be comprised with the light-diffusion adhesive or light-diffusion adhesive agent. The light diffusing element may have a structure having a fine concavo-convex structure on its surface (light diffusing layer of an outward diffusion method), or may have a structure including a matrix and light diffusing fine particles dispersed in the matrix (light diffusing layer of an internal diffusion method). In addition, the light-diffusion element applies a light-diffusion hardened layer (for example, a dispersion liquid (coating liquid for forming a light-diffusion layer) containing a resin for a matrix, light-diffusing fine particles, and, if necessary, an additive) on any suitable substrate, cured and/or dried) or a light diffusing film (for example, a commercially available film). In the light-diffusion adhesive, the matrix is composed of an adhesive, and in the light-diffusion adhesive, the matrix is composed of an adhesive. In addition, when the light-diffusion layer is composed of a light-diffusion adhesive or a light-diffusion adhesive, any suitable protective film may be disposed on the opposite side of the shaping layer of the light-diffusion layer in order to protect the surface of the light-diffusion layer.

The details of a light-diffusion element and a light-diffusion adhesive are, for example, Unexamined-Japanese-Patent No. 2012-83741, Unexamined-Japanese-Patent No. 2012-83742, Unexamined-Japanese-Patent No. 2012-83743, Unexamined-Japanese-Patent No. 2012-83744, It is described in Unexamined-Japanese-Patent No. 2013-235259 and Unexamined-Japanese-Patent No. 2014-224964. The descriptions of these publications are incorporated herein by reference. The light diffusing element of the surface uneven|corrugated type is well-known in the art.

The light diffusion layer is directly disposed on the shaping layer, or laminated with the shaping layer through the shaping layer and the pressure-sensitive adhesive layer or the adhesive layer. The directly disposed shaping layer may be formed by application. As a light-diffusion layer formed in this way, the light-diffusion layer formed by apply|coating the said coating liquid for light-diffusion layer formation, and the light-diffusion layer comprised from a light-diffusion adhesive or a light-diffusion adhesive agent, etc. are mentioned, for example. A light-diffusion film etc. are mentioned as a light-diffusion layer arrange|positioned through an adhesive layer or an adhesive bond layer. The pressure-sensitive adhesive layer for bonding the shaping layer and the light-diffusing layer includes any suitable pressure-sensitive adhesive. As said adhesive, a rubber adhesive, an acrylic adhesive, a silicone adhesive, an epoxy adhesive, a cellulose adhesive, etc. are mentioned, for example, Preferably, it is an acrylic adhesive. The adhesive layer for bonding the shaping layer and the light diffusing layer includes any suitable adhesive. Examples of the adhesive include water-based adhesives (eg, vinyl alcohol-based adhesives) and curable adhesives (eg, active energy ray-curable adhesives or heat-curable adhesives).

The light-diffusion performance of the light-diffusion layer can be expressed by, for example, a haze value. The haze value of the light-diffusion layer is preferably 20% to 90%, more preferably 30% to 87%, still more preferably 40% to 85%. The haze value of the light-diffusion layer can be controlled by adjusting the fine concavo-convex structure on the surface, the constituent material of the matrix (adhesive), and the constituent material of the light-diffusing fine particles, the volume average particle diameter, the blending amount, and the like.

The total light transmittance of the light-diffusion layer is preferably 75% or more, more preferably 80% or more, and still more preferably 85% or more.

The thickness of the light-diffusion layer can be appropriately adjusted according to the configuration, desired light-diffusion performance, and the like. Specifically, the thickness of the light-diffusion layer is preferably 2 µm to 100 µm, more preferably 5 µm to 30 µm.

In one embodiment, the light-diffusion layer is comprised from the light-diffusion adhesive. The light-diffusing pressure-sensitive adhesive typically includes a pressure-sensitive adhesive as a matrix and light-diffusing fine particles dispersed in the pressure-sensitive adhesive.

Any appropriate thing can be used as an adhesive (matrix). Specific examples of the pressure-sensitive adhesive include a rubber pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, an epoxy-based pressure-sensitive adhesive, and a cellulose pressure-sensitive adhesive, and an acrylic pressure-sensitive adhesive is preferred. By using the acrylic pressure-sensitive adhesive, a light-diffusion layer excellent in heat resistance and transparency can be obtained. An adhesive may be used independently and may be used in combination of 2 or more type.

Any appropriate thing can be used as an acrylic adhesive. The glass transition temperature of the acrylic pressure-sensitive adhesive is preferably -60°C to -10°C, more preferably -55°C to -15°C. Preferably the weight average molecular weight of an acrylic adhesive is 200,000-2 million, More preferably, it is 250,000-1.8 million. By using the acrylic pressure-sensitive adhesive having such properties, appropriate adhesiveness can be obtained. The refractive index of the acrylic pressure-sensitive adhesive is preferably 1.40 to 1.65, more preferably 1.45 to 1.60.

The acrylic pressure-sensitive adhesive is usually obtained by polymerizing a main monomer imparting tackiness, a comonomer imparting cohesiveness, and a functional group-containing monomer serving as a crosslinking point while imparting tackiness. The acrylic pressure-sensitive adhesive having the above properties can be synthesized by any suitable method, for example, Dainippon Tosho Co., Ltd. It can be synthesized by referring to the publication “Chemistry and Application of Adhesion and Adhesion” by Katsuhiko Nakamae.

Content of the adhesive in a light-diffusion layer becomes like this. Preferably they are 50 weight% - 99.7 weight%, More preferably, they are 52 weight% - 97 weight%.

Any suitable thing can be used as light-diffusion microparticles|fine-particles. Specific examples of the light diffusing fine particles include inorganic fine particles and polymer fine particles. The light diffusing fine particles are preferably polymer fine particles. Examples of the material of the polymer fine particles include polystyrene resin, polyurethane resin, melamine resin, silicone resin, acrylic resin, and styrene-acrylic copolymer resin. Since these resins have a desired refractive index difference to the pressure-sensitive adhesive and have excellent dispersibility to the pressure-sensitive adhesive, a light-diffusion layer excellent in light-diffusion performance can be obtained. Preferably, it is a polystyrene resin. The shape of the light-diffusing fine particles may be, for example, a spherical shape, a flat shape, or an irregular shape. Light-diffusing microparticles|fine-particles may be used independently and may be used in combination of 2 or more type.

The volume average particle diameter of the light diffusing fine particles is preferably larger than 1 µm and 30 µm or less, more preferably 2 µm to 30 µm, still more preferably 2 µm to 25 µm, particularly preferably 3 µm. -20 μm. By making a volume average particle diameter into the said range, the light-diffusion layer which has the outstanding optical characteristic can be obtained. In particular, when light-diffusing fine particles having a volume average particle diameter of 2 µm or more are used, a light-diffusion layer having remarkably excellent optical properties, such as preventing coloration of transmitted light, can be obtained. The volume average particle diameter can be measured using an automatic ultracentrifugal particle size distribution measuring device.

The refractive index of the light diffusing fine particles is preferably 1.50 or more, more preferably 1.55 to 1.70, still more preferably 1.58 to 1.65.

The absolute value of the refractive index difference between the light-diffusing fine particles and the pressure-sensitive adhesive (matrix) is preferably 0.05 or more, more preferably 0.07 to 0.15, and still more preferably 0.10 to 0.13.

Content of the light-diffusion microparticles|fine-particles in a light-diffusion layer becomes like this. Preferably it is 0.3 weight% - 50 weight%, More preferably, they are 3 weight% - 48 weight%. By making the compounding quantity of light-diffusion microparticles|fine-particles into the said range, the light-diffusion layer which has the outstanding light-diffusion performance can be obtained.

The light-diffusion layer may contain arbitrary appropriate additives. As an additive, an antistatic agent and antioxidant are mentioned, for example.

In another embodiment, the light-diffusion layer is comprised of a light-diffusion element. In this case, the light-diffusion layer typically includes a matrix and light-diffusing fine particles dispersed in the matrix. The matrix is composed of, for example, an ionizing ray-curable resin. As an ionizing beam, an ultraviolet-ray, visible light, infrared rays, and an electron beam are mentioned, for example. It is preferably ultraviolet, and therefore the matrix is preferably composed of an ultraviolet curable resin. As ultraviolet curable resin, an acrylic resin, an aliphatic type (for example, polyolefin) resin, and a urethane type resin are mentioned, for example. As for the light-diffusing fine particles, the same fine particles as the light-diffusing fine particles that can be used for the light-diffusing pressure-sensitive adhesive can be used. Further, in the present embodiment, the matrix may contain a resin component and an ultrafine particle component. In this case, a refractive index modulation region in which the refractive index is changed substantially continuously may be formed outside the vicinity of the surface of the light diffusing fine particles. The refractive index modulation region is typically formed by a substantial gradient in the dispersion concentration of the ultrafine particle component in the matrix. By adopting such a configuration, backscattering can be suppressed. The resin component is preferably composed of an ultraviolet curable resin (eg, acrylic resin) as described above. Specific examples of the monomer component constituting the acrylic resin include pentaerythritol triacrylate (PETA: molecular weight 298), neopentyl glycol diacrylate (NPGDA: molecular weight 212), dipentaerythritol hexaacrylate (DPHA: molecular weight 632), dipenta Erythritol pentaacrylate (DPPA: molecular weight 578) and trimethylolpropane triacrylate (TMPTA: molecular weight 296) are mentioned. The ultrafine particle component is preferably composed of an inorganic compound. As a preferable inorganic compound, a metal oxide and a metal fluoride are mentioned, for example. Specific examples of the metal oxide include zirconium oxide (zirconia) (refractive index: 2.19), aluminum oxide (refractive index: 1.56 to 2.62), titanium oxide (refractive index: 2.49 to 2.74), and silicon oxide (refractive index: 1.25 to 1.46). Specific examples of the metal fluoride include magnesium fluoride (refractive index: 1.37) and calcium fluoride (refractive index: 1.40 to 1.43). Details of the light-diffusion layer (light-diffusion element) including such a matrix are described in, for example, Japanese Patent Application Laid-Open No. 2010-250295 or Japanese Patent Application Laid-Open No. 2012-088692, and these descriptions are incorporated herein by reference. do.

B. Optical laminate

B-1. full configuration

It is a schematic sectional drawing of the optical laminated body by one Embodiment of this invention. The optical laminate 200 of the illustrated example includes a light diffusing film 100 and another film 110 disposed on one side of the light diffusing film 100 . The light-diffusion film 100 and the other film 110 are laminated so that the concave-convex portions 12 of the shaping layer 10 included in the light-diffusion film 100 and the other film 110 face each other. Typically, the light-diffusion film 100 and the other film 110 are laminated through the adhesive layer 120 .

As described above, in the concave-convex portion 12 of the light-diffusion film 100, the ratio (B/A) of the cross-sectional area (B) of the concave portion to the cross-sectional area (A) of the entire concave-convex portion (B/A) is preferably 50% or more. and more preferably more than 50%, still more preferably 60% or more, and particularly preferably 70% or more. The upper limit of the ratio (B/A) may be, for example, 90%. The ratio (B/A) may correspond to the porosity. If it is such a range, while realizing favorable light-diffusion performance, a luminance viewing angle can be enlarged, and the optical laminated body excellent in mechanical strength can be obtained.

B-2. other film

Any suitable film may be employed as the other film. As another film, For example, Optical films, such as a polarizer, a wavelength conversion film, and a polarization reflection film; glass (preferably thin glass); A resin film (for example, a protective film) etc. are mentioned.

In one embodiment, a polarizer is used as another film. In this embodiment, the said light-diffusion film functions as a polarizer protective film, and the said optical laminated body can become a polarizing plate. The details of the polarizing plate will be described later.

B-3. adhesive layer

The adhesive layer is comprised of any suitable adhesive or tackifier. The adhesive layer is typically formed of a water-based adhesive (eg, a vinyl alcohol-based adhesive) or a curable adhesive (eg, an active energy ray-curable adhesive or a heat-curable adhesive).

In one embodiment, the said adhesive layer contains an active energy ray hardening-type adhesive agent. When an adhesive layer is formed using an active energy ray hardening-type adhesive agent, an optical laminated body can be obtained, without impairing the uneven|corrugated shape of a light-diffusion film.

As the active energy ray-curable adhesive, any suitable adhesive can be used as long as it can be cured by irradiation with an active energy ray. Examples of the active energy ray curing adhesive include an ultraviolet curing adhesive and an electron beam curing adhesive. Specific examples of the curing type of the active energy ray curing adhesive include a radical curing type, a cation curing type, an anion curing type, and combinations thereof (for example, a hybrid of a radical curing type and a cation curing type).

Examples of the active energy ray-curable adhesive include, as a curing component, an adhesive containing a compound (eg, a monomer and/or an oligomer) having a radically polymerizable group such as a (meth)acrylate group or a (meth)acrylamide group. can

The specific example of the said active energy ray hardening-type adhesive agent and its hardening method is described in Unexamined-Japanese-Patent No. 2012-144690, for example. The above description is incorporated herein by reference.

As a method of applying the active energy ray-curable adhesive, any suitable method may be employed depending on the viscosity of the adhesive and the desired thickness of the adhesive layer or the like. Examples of the coating method include application by a reverse coater, a gravure coater (direct, reverse or offset), a reverse coater, a roll coater, a die coater, a bar coater, and a rod coater. Moreover, you may employ|adopt the application|coating by a dipping method.

Any suitable method can be employ|adopted as a hardening method of the said active energy ray-curable adhesive agent. Conditions, such as the wavelength of an active energy ray, irradiation amount, etc. can be set to arbitrary suitable conditions according to the kind of curable compound used, etc.

The thickness of the portion where the thickness of the adhesive layer becomes the maximum is preferably 0.5 µm to 10 µm, more preferably 0.5 µm to 5 µm. If it is such a range, the space|gap by the unevenness|corrugation of a mold film can be formed suitably, and the optical laminated body excellent in mechanical strength can be obtained. In one embodiment, the portion where the thickness of the adhesive layer becomes the maximum corresponds to a gap from the upper surface of the convex portion (the surface facing the other film) of the light-diffusion film to the lower surface of the other film (the surface opposite to the light-diffusion film) can do. In another embodiment, the portion where the thickness of the adhesive layer is maximum may be a position corresponding to the concave portion of the light-diffusion film (FIG. 4). For example, an adhesive layer may be formed so as to cover at least a part of the wall surface of the convex part of a light-diffusion film. At this time, it is preferable that the adhesive layer is not formed on the concave surface of the light-diffusion film, but has a so-called meniscus shape. In this embodiment, while ensuring a space|gap, the optical laminated body excellent in the adhesiveness of a light-diffusion film and another film can be obtained.

In one embodiment, it is preferable that the thickness (T) of the adhesive layer formed in the upper surface of the convex part of a light-diffusion film is thinner than the thickness (height) (H) of the convex part. The ratio (T/H) of the thickness T and the height H of the convex portion is preferably 50% or less, and more preferably 30% or less. If ratio (T/H) is such a range, favorable adhesive bonding can be implement|achieved. The lower limit of the ratio (T/H) may be, for example, 10%.

The light-diffusion film has concavo-convex portions, and the convex portions of the light-diffusion film and other films are adhered (that is, adhesively adhered) and laminated. It is preferable to be In other words, it is preferable that the adhesive layer covers at least a portion (preferably all) of the surface of the other film in the concave portion (void portion) of the light-diffusion film. In this way, deterioration of other films can be prevented. This effect is particularly useful when the other film is deteriorated by moisture, outside air, or the like, for example, when the other film is a polarizer. The thickness of the contact bonding layer in a space|gap part may be constant, and may not be constant. In one embodiment, the adhesive layer of the void portion has a meniscus shape and its thickness is not constant. As a method of forming an adhesive layer in a space|gap part, after forming an adhesive precursor layer on another film, for example, the method of bonding the said other film and a light-diffusion film is mentioned.

Preferably the storage elastic modulus in 25 degreeC of the said contact bonding layer is 100 kPa or more, More preferably, they are 100 kPa - 3 GPa, More preferably, they are 100 kPa - 1 GPa. If it is such a range, the space|gap by the unevenness|corrugation of a light-diffusion film can be formed suitably, and the optical laminated body excellent in mechanical strength can be obtained. In addition, the storage modulus can be calculated|required by dynamic viscoelasticity measurement. Dynamic viscoelasticity measurement is, for example, using "Advanced Rheometric Expansion System (ARES)" manufactured by Rheometric Scientific for a pressure-sensitive adhesive sample having a thickness of 2 mm × diameter 8 mm, deformation mode: torsion, measurement frequency: 1 Hz, temperature increase rate 5°C /min, measurement temperature: It can carry out at -50 degreeC - 150 degreeC.

B-4. Polarizer

As mentioned above, in one Embodiment, the said optical laminated body is a polarizing plate. 4 is a schematic cross-sectional view of a polarizing plate according to one embodiment of the present invention. The polarizing plate 200a of the illustrated example includes a polarizer 110a and a polarizer protective film 100a laminated on the polarizer 110a through an adhesive layer 120 . The polarizer protective film 100a in this embodiment corresponds to the said light-diffusion film. In addition, the polarizer 110a corresponds to the said other film. The polarizer protective film 100a is arranged so that the concave-convex portion side becomes the polarizer 110a side. The adhesive layer is as described above. Practically, another protective film 140 is disposed on the opposite side to the polarizer protective film 100a. Practically, the pressure-sensitive adhesive layer 150 is formed as the outermost layer, enabling the polarizing plate to be attached to the image display cell. In addition, a separator (not shown) is detachably attached to the surface of the pressure-sensitive adhesive layer 150 to protect the pressure-sensitive adhesive layer until the polarizing plate is actually used and to enable roll formation. The polarizing plate according to the embodiment of the present invention may be used as a rear-side polarizing plate of an image display device, or may be used as a viewing-side polarizing plate. According to embodiment of this invention, since polarizer protective film itself has light-diffusion performance and serves also as a light-diffusion film, remarkable thickness reduction can be implement|achieved by the synergistic effect with the exclusion effect of an air layer.

Any suitable polarizer may be employed as the polarizer. For example, a single-layered resin film may be sufficient as the resin film which forms a polarizer, and the laminated body of two or more layers may be sufficient as it.

As a specific example of a polarizer composed of a single-layer resin film, a polyvinyl alcohol (PVA)-based film, a partially formalized PVA-based film, an ethylene/vinyl acetate copolymer-based partially saponified film, etc. Polyene-type oriented films, such as a thing to which the dyeing process by a dichroic substance and extending|stretching process were given, the dehydration-processed material of PVA, and the dehydrochloric acid-treated material of polyvinyl chloride, etc. are mentioned. Preferably, since it is excellent in an optical characteristic, the polarizer obtained by dyeing|staining a PVA-type film with iodine and uniaxial stretching is used.

Dyeing with the said iodine is performed, for example by immersing a PVA-type film in iodine aqueous solution. Preferably the draw ratio of the said uniaxial stretching is 3-7 times. Extending|stretching may be performed after a dyeing process, and may be performed, dyeing|staining. Moreover, after extending|stretching, you may dye|dye. If necessary, a swelling treatment, a crosslinking treatment, a washing treatment, a drying treatment, and the like are applied to the PVA-based film. For example, by immersing the PVA-based film in water and washing with water before dyeing, not only can the surface of the PVA-based film be cleaned of stains and anti-blocking agents, but also the PVA-based film can be swollen to prevent staining of dyeing.

As a specific example of a polarizer obtained using a laminate, a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate and a polarizer obtained using A polarizer obtained by using a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate is applied, for example, by applying a PVA-based resin solution to the resin substrate and drying to form a PVA-based resin layer on the resin substrate, obtaining a laminate of a resin substrate and a PVA-based resin layer; It can be produced by; stretching and dyeing the laminate to use the PVA-based resin layer as a polarizer. In this embodiment, extending|stretching includes extending|stretching by immersing a laminated body in boric-acid aqueous solution typically. In addition, the stretching may further include air stretching the laminate at a high temperature (for example, 95° C. or higher) before stretching in an aqueous boric acid solution if necessary. The obtained laminate of resin substrate/polarizer may be used as it is (that is, the resin substrate may be used as a protective layer of the polarizer), and the resin substrate is peeled from the laminate of resin substrate/polarizer, may be used by laminating an appropriate protective layer of The detail of the manufacturing method of such a polarizer is described in Unexamined-Japanese-Patent No. 2012-73580, for example. The above publication is incorporated herein by reference in its entirety.

The thickness of the polarizer is, for example, 1 µm to 80 µm. In one embodiment, the thickness of a polarizer becomes like this. Preferably they are 1 micrometer - 20 micrometers, More preferably, they are 3 micrometers - 15 micrometers.

The polarizer protective film preferably has substantially optically isotropy. In this specification, "having substantially optically isotropy" means that the in-plane retardation Re(550) is 0 nm to 10 nm. The in-plane retardation Re(550) is more preferably 0 nm to 5 nm, still more preferably 0 nm to 3 nm, and particularly preferably 0 nm to 2 nm. If Re (550) of the polarizer protective film is within this range, adverse effects on display characteristics can be prevented when a polarizing plate including the polarizer protective film is applied to an image display device. In addition, Re(550) is the in-plane retardation of the film measured with the light of wavelength 550nm in 23 degreeC. Re(550) is obtained by the formula: Re(550) = (nx-ny)×d. Here, nx is the refractive index in the direction in which the in-plane refractive index is maximized (ie, the slow axis direction), ny is the refractive index in the direction orthogonal to the slow axis in the plane (ie, the fast axis direction), and d is the thickness of the film (nm).

It is so preferable that the light transmittance in 380 nm in 40 micrometers in thickness of a polarizer protective film is high. Specifically, the light transmittance is preferably 75% or more, more preferably 80% or more, and still more preferably 85% or more. If the light transmittance is within such a range, desired optical properties can be secured. The light transmittance can be measured, for example, by a method according to ASTM-D-1003.

The haze of the polarizer protective film is preferably 50% to 99%, more preferably 70% to 95%.

It is preferable that a polarizer protective film has the following characteristics. Assuming that the light transmittance at 550 nm is 100%, the difference between the light transmittances at 450 nm and 650 nm with the light transmittance at 550 nm is preferably within ±5%, more preferably within ±2%.

Regarding the luminance viewing angle of the polarizer protective film, the luminance half-maximum angle (angle at which the luminance is 50% of the front surface) is preferably 56° (28° on one side) or more, more preferably 60° to 70° (30° on one side to 35°). The angle at which the luminance is 25% of the front is preferably 90° (45° on one side) or more, more preferably 96° to 120° (48° to 60° on one side). ADVANTAGE OF THE INVENTION According to embodiment of this invention, a polarizer protective film can provide the outstanding diffusion performance, and can maintain a brightness|luminance viewing angle widely.

The refractive index (n _F ) of the entire polarizer protective film is preferably 1.3 to 1.8, more preferably 1.4 to 1.6. If the refractive index of a polarizer protective film is such a range, in a polarizing plate, the refractive index difference with the low-refractive-index part prescribed|regulated by the point adhesion with a polarizer can be made into a desired range.

The moisture permeability of the polarizer protective film is preferably 300 g/m 2 ·24 hr or less, more preferably 250 g/m 2 · 24 hr or less, still more preferably 200 g/m 2 · 24 hr or less, particularly preferably 150 g/m 2 · 24 hr or less, most preferably Preferably it is 100 g/m<2>*24hr or less. If the moisture permeability of the polarizer protective film is within this range, a polarizing plate having excellent durability and moisture resistance can be obtained.

C. Image display device

The polarizing plate may be applied to an image display device. Accordingly, the present invention also includes an image display device using such a polarizing plate. Representative examples of the image display device include a liquid crystal display device and an organic electroluminescence (EL) display device. Since the image display apparatus employs a configuration well known in the industry, a detailed description thereof will be omitted.

Example

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. The measuring method of each characteristic is as follows. In addition, unless otherwise indicated, "part" and "%" in an Example are a weight basis.

(1) workability (tear strength)

The tearing strength of the shaping|shaping layer was performed by the method according to JISK7128-1 using the trouser tearing method. A test piece was cut to a predetermined size under constant temperature conditions (23°C, 50% relative humidity), a 75 mm slit was put, and a tear test was performed at a speed of 200 mm/min. It calculated|required from the average value of the tear strength of the remaining 50 mm except 20 mm of the tear start and 5 mm before the end of a tear. The test was performed with N=5, and the average value was calculated|required.

When tearing strength is 0.5 N or less, since there exists a possibility of fracture|rupture at the time of film forming, it was set as NG.

(2) optical properties

The content of the light-diffusing fine particles is adjusted so that the haze of the light-diffusion film is 80%, the transmittance T (450) at a wavelength of 450 nm, the transmittance T (550) at a wavelength of 550 nm, the transmittance T in a wavelength of 650 nm (650) was measured.

The case where the value of (T(450)-T(650))/T(550) was within ±0.5 was regarded as pass (circle). The passed product had no coloration of transmitted light and had excellent optical properties.

(3) Humidification durability

After applying the adhesive to the surface of the polarizer in a thickness of 1 μm, the polarizer and the uneven surface of the light diffusion film (polarizer protective film) obtained in Examples and Comparative Examples are bonded, and then UV irradiated and the adhesive is cured, The polarizing plate which consists of shaping film (polarizer protective film)/adhesive layer/polarizer was obtained.

The shaping film (polarizer protective film) of the said polarizing plate and the glass plate were laminated|stacked through the acrylic adhesive. The obtained laminate was left to stand for 500 hours in an environment with a temperature of 60°C and a humidity of 90%. Then, the transmittance|permeability of the laminated body was measured with the light absorption spectrometer ("V7100" by JASCO Corporation) equipped with an integrating hole.

With respect to the transmittance before heating and humidification, the case where the transmittance after heating and humidification changed by 10% or more was regarded as fail (x), and the case where the change was less than 10% was regarded as pass (○).

<Example 1>

A methacrylic resin (manufactured by KURARAY. Co., Ltd., product name "PARAPET HR-S") is put into a single screw extruder, melt-extruded at 260 ° C. A layer (thickness: 50 µm, convex part height: 10 µm, cell size: 15000 µm ² ) was obtained.

What blended 10 parts of silica particles with a volume average particle diameter of 10 micrometers with an acrylic ultraviolet-curing resin was apply|coated to the side which does not have the uneven shape of the said shaping|shaping layer. An ultraviolet-ray was irradiated to the said coating layer, the ultraviolet curable resin was hardened, the light-diffusion layer was formed, and the light-diffusion film was obtained.

The obtained light-diffusion film was used for the said evaluation (1)-(3). A result is shown in Table 1.

<Example 2>

A light-diffusion film was obtained in the same manner as in Example 1 except that silica particles having a volume average particle diameter of 6 µm were used as the silica particles of the light-diffusion layer.

The obtained light-diffusion film was used for the said evaluation (1)-(3). A result is shown in Table 1.

<Example 3>

A light-diffusion film was obtained in the same manner as in Example 1 except that silica particles having a volume average particle diameter of 2 µm were used as the silica particles of the light-diffusion layer.

The obtained light-diffusion film was used for the said evaluation (1)-(3). A result is shown in Table 1.

<Example 4>

A shaping layer was obtained in the same manner as in Example 1.

On the side having no concavo-convex shape of the shaping layer, the shaping layer and the acrylic film were laminated through an adhesive film (light-diffusion pressure-sensitive adhesive) in which silica particles were dispersed in an acrylic pressure-sensitive adhesive to obtain a light-diffusing film.

The obtained light-diffusion film was used for the said evaluation (1)-(3). A result is shown in Table 1.

<Example 5>

A shaping layer was obtained in the same manner as in Example 1.

On the side having no concavo-convex shape of the shaping layer, the shaping layer and the light-diffusing film (manufactured by KIMOTO CO., LTD., trade name "Diffusion Film MXE") were laminated through an acrylic adhesive to obtain a light-diffusing film. The light-diffusing film was laminated|stacked with the surface on the opposite side to the diffusion layer as the shaping|shaping layer side.

The obtained light-diffusion film was used for the said evaluation (1)-(3). A result is shown in Table 1.

<Comparative Example 1>

With respect to 100 parts of methacrylic resin (manufactured by KURARAY. Co., Ltd., product name “PARAPET HR-S”), 9 parts of silicone resin fine particles (volume average particle diameter 4.5 μm) as light diffusing fine particles were put into a single screw extruder, , while melt-extruding at 260° C., an uneven shape was formed on one surface with an embossing roll to obtain a light-diffusion film (thickness: 50 µm, convex height: 10 µm, cell size: 15000 µm ² ).

The obtained light-diffusion film was used for the said evaluation (1)-(3). A result is shown in Table 1.

<Comparative Example 2>

3M Ltd. The prism film BEF2-T-155 made from the product was subjected to the above evaluation (3). In that case, after apply|coating the adhesive agent to the surface of a polarizer at 1 micrometer, adhesion|attachment with the prism side of the said prism film was performed.

(Industrial Applicability)

The light-diffusion film of the present invention can be used in various fields as a film capable of imparting a light-diffusion function. For example, the light-diffusion film of this invention is used suitably for a polarizing plate. The polarizing plate of the present invention is suitably used for an image display device. The image display apparatus of the present invention includes portable devices such as a portable information terminal (PDA), a smart phone, a mobile phone, a watch, a digital camera, and a portable game machine; OA equipment such as PC monitors, notebook computers, and photocopiers; household electrical appliances such as video cameras, televisions, and microwaves; In-vehicle devices such as a back monitor, a monitor for a car navigation system, and a car audio system; display devices such as digital signage and information monitors for commercial stores; security devices such as monitors for monitoring; Nursing care/medical equipment, such as a long-term care monitor and a medical monitor; It can be used for various uses, such as

10: excipient layer
11: Ministry of Finance
12: uneven part
12a: convex part
12b: recess
20: light diffusion layer
100: light diffusion film
110: another film
120: adhesive layer
200: optical laminate

Claims (6)

A shaping layer and a light diffusion layer disposed on one side of the shaping layer,
The shaping layer includes a base part and an uneven part disposed on one side of the base part,
The light-diffusion layer is a light-diffusion film disposed on the side of the base portion of the shaping layer. The method of claim 1,
The light-diffusion film and the light-diffusing layer are laminated through a pressure-sensitive adhesive layer or an adhesive layer. The method of claim 1,
The light-diffusion layer is a light-diffusion film formed directly on the shaping layer. 4. The method according to any one of claims 1 to 3,
The light-diffusing layer includes light-diffusing particles,
The light-diffusing film having a volume average particle diameter of the light-diffusing fine particles is 2 µm to 30 µm. 5. The method according to any one of claims 1 to 4,
A light-diffusing film having a haze value of 30% to 95%. A polarizing plate provided with a polarizer and the light-diffusion film in any one of Claims 1-5 laminated|stacked through the said polarizer and an adhesive layer.

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