CN117396782A

CN117396782A - Optical laminate, polarizing plate, image display device, and method for manufacturing optical laminate

Info

Publication number: CN117396782A
Application number: CN202280038786.9A
Authority: CN
Inventors: 须贺田宏士; 小野哲哉; 太田隆明
Original assignee: Dexerials Corp
Current assignee: Dexerials Corp
Priority date: 2021-06-08
Filing date: 2022-05-23
Publication date: 2024-01-12

Abstract

The invention maintains antiglare property and improves scratch resistance. An optical laminate (10) of the present invention is provided with: a transparent base material (11); at least one hard coat layer (12) provided on the transparent base material (11) and formed of a resin composition; and at least one or more metal oxide layers (an adhesion layer (13) and an antireflection layer (14)) provided on the hard coat layer (12) and made of a metal oxide, wherein a concave-convex structure is formed on the surface of the hard coat layer (12) on the metal oxide layer side, and the height distribution of the surface of the concave-convex structure satisfies the following formula (1). A/1.9< P … … (1) A: when the height B of the lowest point of the surface of the concave-convex structure is set to 0, the height of the highest point of the surface of the concave-convex structure. P: when the height B of the lowest point of the surface of the concave-convex structure is set to 0, the mode of the height distribution of the surface of the concave-convex structure is set.

Description

Optical laminate, polarizing plate, image display device, and method for manufacturing optical laminate

Technical Field

The invention relates to an optical laminate, a polarizing plate, an image display device, and a method for manufacturing the optical laminate.

Background

The antireflection film is a transparent film having antireflection property. Conventionally, an optical laminate including a multilayer film in which a high refractive index layer and a low refractive index layer are sequentially laminated on a transparent substrate has been used as an antireflection film. The antireflection film is provided on a display screen of a display device such as a Liquid Crystal Display (LCD), a Plasma Display Panel (PDP), or an Organic Electro-Luminescence Display (OELD). This reduces the reflectance of the display screen by using the principle of optical interference, and suppresses the reduction in contrast and reflection of an image due to reflection of external light on the display screen.

Further, as an antireflection film, an AGAR type film having antiglare properties (anti-glare: AG) in addition to antireflection properties (anti-reflection: AR) has been developed. In order to impart antiglare properties to an antireflection film, the following techniques have been proposed: a rough surface structure using micro-sized particles (filler) is formed on the film surface, and incident light is scattered by the rough surface structure.

For example, patent document 1 discloses the following technology for imparting antiglare properties to an antireflection film: by dispersing the matte particles of 1 μm or more and 10 μm or less in the antiglare hard coat layer as the high refractive index layer, a protrusion-like structure having hillock-like protrusions corresponding to the particle shape of the matte particles is formed on the surface of the antireflection film. Further, patent document 2 discloses the following technique: the antiglare layer contains light-transmitting fine particles having a diameter of 2 μm or more and 5 μm or less or an inorganic filler, and has a protrusion-like structure having hillock-like protrusions on the film surface.

Prior art literature

Patent literature

Patent document 1: japanese patent No. 5331919

Patent document 2: japanese patent No. 4431540

Disclosure of Invention

Problems to be solved by the invention

However, if a projection-like structure is formed on the surface of the antireflection film as described in patent documents 1 and 2 in order to impart antiglare properties to the antireflection film, there is a problem that the scratch resistance of the antireflection film is lowered. For example, in the case where an antireflection film is provided on a display screen such as a touch panel of a smart phone or various operation devices, a load applied to the surface screen by an operator's finger, a pointing device, or the like is concentrated on a projecting portion of the projecting structure. Therefore, the protruding structure is easily abraded and damaged, and the abrasion resistance of the film surface is lowered. Therefore, conventionally, by eliminating the protruding structure as much as possible in the surface of the antireflection film and forming the recessed rough surface structure, an optical laminate that can maintain antiglare properties and also improve scratch resistance of the film surface has been demanded.

The present invention has been made in view of the above-described problems, and an object thereof is to provide an optical laminate which can maintain antiglare properties and improve scratch resistance, and a polarizing plate, an image display device, and a method for manufacturing an optical laminate each including the optical laminate.

Solution for solving the problem

In order to solve the above-described problems, according to one aspect of the present invention, there is provided an optical laminate comprising: a transparent substrate; at least one hard coat layer provided on the transparent substrate and formed of a resin composition; and at least one or more metal oxide layers provided on the hard coat layer and composed of a metal oxide, wherein a concave-convex structure is formed on the surface of the hard coat layer on the metal oxide layer side, and the height distribution of the surface of the concave-convex structure satisfies the following formula (1).

A/1.9<P……(1)

A: when the height B of the lowest point of the surface of the concave-convex structure is set to 0, the height of the highest point of the surface of the concave-convex structure.

P: and a mode of height distribution of the surface of the concave-convex structure when the height B of the lowest point of the surface of the concave-convex structure is set to 0.

The tops of the plurality of convex portions constituting the concave-convex structure of the hard coat layer may have substantially the same height as each other.

The outermost surface of the optical laminate may be a concave-convex surface formed to follow the shape of the concave-convex structure of the hard coat layer, and the tops of the plurality of convex portions constituting the concave-convex surface may have substantially the same height as each other.

The top portions of the plurality of convex portions constituting the concave-convex structure of the hard coat layer may each have a substantially flat surface.

The outermost surface of the optical laminate may be a concave-convex surface formed to follow the shape of the concave-convex structure of the hard coat layer, and the top portions of the plurality of convex portions constituting the concave-convex surface may each have a substantially flat surface.

The surface roughness Sa of the uneven structure of the hard coat layer may be 50nm or more and 300nm or less.

The friction tester using steel wool may be used to load the steel wool with: 1kg, contact area: 1 cm. Times.1 cm, reciprocating: the contact angle of the outermost surface of the optical laminate after rubbing the surface of the optical laminate 2000 times to water is 90 degrees or more.

The external haze value defined in JIS K7136 may be 3% or more and 40% or less.

The hard coat layer may contain metal oxide fine particles having an average particle diameter of 20nm to 100 nm.

The hard coat layer may not contain filler particles having an average particle diameter of 1 μm or more.

The metal oxide layer may include an antireflection layer, the antireflection layer may be formed of a laminate in which a low refractive index layer and a high refractive index layer are alternately laminated, the high refractive index layer having a refractive index larger than that of the low refractive index layer, and the optical laminate may be an antireflection film having an antiglare function and an antireflection function.

The metal oxide layer may include an adhesion layer provided between the hard coat layer and the anti-reflection layer.

In order to solve the above-described problems, according to another aspect of the present invention, there is provided a polarizing plate including the above-described optical laminate.

In order to solve the above-described problems, according to another aspect of the present invention, there is provided an image display device including the optical laminate.

In order to solve the above-described problems, according to another aspect of the present invention, there is provided a method for manufacturing an optical laminate, comprising: providing a hard coat layer formed of a resin composition on a transparent substrate; providing at least one or more metal oxide layers on the hard coating layer; and disposing an antifouling layer on the metal oxide layer, wherein the disposing of the hard coat layer includes: coating the resin composition on the surface of the transparent substrate; and transferring the concave-convex shape of the transfer mold to the resin composition.

Effects of the invention

According to the present invention, the scratch resistance can be improved while maintaining the antiglare property.

Drawings

Fig. 1 is a cross-sectional view showing an optical laminate according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view showing an example of the hard coat layer according to this embodiment.

Fig. 3 is a view showing a 3D image of an example of the optical layered body according to this embodiment.

Fig. 4 is a view showing a cross-sectional roughness of an example of the optical laminate of this embodiment.

Fig. 5 is a flowchart showing a method for manufacturing an optical laminate according to this embodiment.

Fig. 6 is a process diagram illustrating an example of a method for manufacturing a transfer mold according to this embodiment.

Fig. 7 is a process diagram illustrating the coating process and the transfer process of this embodiment.

Fig. 8 is a graph showing a histogram of sample a of the comparative example.

Fig. 9 is a diagram showing a histogram of sample B of the comparative example.

Fig. 10 is a graph showing a histogram of sample C of the comparative example.

Fig. 11 is a diagram showing a histogram of sample D of the comparative example.

Fig. 12 is a graph showing a histogram of sample E of the comparative example.

Fig. 13 is a graph showing a histogram of sample K of the comparative example.

Fig. 14 is a graph showing a histogram of sample F of the example.

Fig. 15 is a graph showing a histogram of sample G of the example.

Fig. 16 is a diagram showing a histogram of sample H of the example.

Fig. 17 is a graph showing a histogram of sample I of the example.

Fig. 18 is a graph showing a histogram of sample J of the example.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, other specific values, etc. shown in this embodiment are merely examples for easy understanding of the invention, and the invention is not limited thereto unless otherwise stated. In the present specification and the drawings, elements having substantially the same functions and structures are denoted by the same reference numerals, so that duplicate descriptions thereof are omitted, and elements not directly related to the present invention are omitted from illustration.

In the drawings referred to in the following description, the sizes of some of the constituent elements may be exaggerated for convenience of description. Therefore, the relative sizes of the constituent elements illustrated in the drawings do not necessarily accurately represent the actual size relationship of the constituent elements.

[1 ] integral Structure of optical laminate

First, the overall structure of an optical laminate 10 according to an embodiment of the present invention will be described with reference to fig. 1. Fig. 1 is a cross-sectional view showing an optical laminate 10 according to the present embodiment.

The optical laminate 10 of the present embodiment is used as an AGAR antireflection film having an antiglare function (anti-glare: AG) and an antireflection function (anti-reflection: AR), for example. As shown in fig. 1, the optical laminate 10 of the present embodiment is formed by laminating a transparent substrate 11, a hard coat layer 12, an adhesive layer 13, an antireflection layer 14, and an antifouling layer 15 in this order. The respective layers will be described below.

[ transparent substrate 11]

The transparent substrate 11 is formed of, for example, a transparent material that transmits light in the visible light range having a wavelength of 350nm or more and 830nm or less. In the present embodiment, the "transparent material" is a material having a transmittance of light in a wavelength region of 80% or more, for example, within a range that does not impair the effect of the optical laminate 10 of the present embodiment.

The transparent substrate 11 may be made of, for example, a plastic film as an organic material or a glass film as an inorganic material. The constituent material of the plastic film is any one or more of polyester-based resin, acetate-based resin, polyethersulfone-based resin, polycarbonate-based resin, polyamide-based resin, polyimide-based resin, polyolefin-based resin, (meth) acrylic resin, polyvinyl chloride-based resin, polyvinylidene chloride-based resin, polystyrene-based resin, polyvinyl alcohol-based resin, polyarylate-based resin, and polyphenylene sulfide-based resin, preferably any one or more of polyester-based resin, acetate-based resin, polycarbonate-based resin, and polyolefin-based resin. In the present embodiment, "(meth) acrylic acid" means methacrylic acid and acrylic acid.

The transparent substrate 11 is constituted, for example, of one or more selected from the group consisting of: polycarbonate (PC), polyethylene terephthalate (PET), cellulose Triacetate (TAC), polyimide (PI), polymethyl methacrylate (PMMA), cyclic Olefin Polymer (COP), cyclic Olefin Copolymer (COC), and glass.

In this embodiment, an example in which the transparent substrate 11 is made of cellulose Triacetate (TAC) will be described. When the transparent base material 11 is made of TAC, a permeation layer in which a part of the components constituting the hard coat layer 12 permeates is formed when the hard coat layer 12 is formed on one surface side thereof. As a result, the adhesion between the transparent substrate 11 and the hard coat layer 12 is improved, and the occurrence of interference fringes due to the difference in refractive index between the layers can be suppressed.

Further, the transparent base material 11 may contain a reinforcing material as long as the optical characteristics are not significantly impaired. The reinforcing material is, for example, cellulose nanofibers, nanosilica, etc.

The transparent substrate 11 may be a film to which one or both of an optical function and a physical function are imparted. Examples of the film having one or both of an optical function and a physical function include: a polarizing plate, a retardation compensation film, a heat ray insulation film, a transparent conductive film, a brightness enhancement film, a barrier enhancement film, and the like.

The thickness of the transparent substrate 11 is not particularly limited, and is, for example, 10 μm or more and 500 μm or less, preferably 25 μm or more and 188 μm or less, more preferably 40 μm or more and 100 μm or less, from the viewpoints of handleability, flexibility, cost and characteristics.

When the thickness of the transparent substrate 11 is 25 μm or more, the rigidity of the substrate itself is ensured, and wrinkles are less likely to occur even when stress is applied to the optical laminate 10. Further, when the thickness of the transparent base material 11 is 25 μm or more, wrinkles are less likely to occur even if the hard coat layer 12 is continuously formed on the transparent base material 11, and the production is less likely to occur. When the thickness of the transparent substrate 11 is 40 μm or more, wrinkles are less likely to occur, which is preferable.

In the case of using a roll in manufacturing the optical laminate 10, the thickness of the transparent substrate 11 is preferably 1000 μm or less, more preferably 600 μm or less. When the thickness of the transparent base material 11 is 1000 μm or less, the optical laminate 10 during production and the optical laminate 10 after production can be easily wound into a roll, and the optical laminate 10 can be efficiently produced. Further, when the thickness of the transparent substrate 11 is 1000 μm or less, the optical laminate 10 can be made thinner and lighter. When the thickness of the transparent substrate 11 is 600 μm or less, the optical laminate 10 can be manufactured more efficiently, and further, it is preferable that the thickness be reduced and the weight be further reduced.

The transparent substrate 11 may be subjected to one or more of various treatments such as sputtering, corona discharge, ultraviolet irradiation, electron beam irradiation, chemical conversion, oxidation, and other etching treatments. By performing these treatments in advance on the surface of the transparent substrate 11, the adhesion between the hard coat layer 12 formed on the transparent substrate 11 and the transparent substrate 11 can be improved. It is also preferable that the surface of the transparent substrate 11 is cleaned by solvent cleaning, ultrasonic cleaning, or the like, as necessary, before the hard coat layer 12 is formed on the transparent substrate 11, so that the surface of the transparent substrate 11 is cleaned in advance.

[ hard coating 12]

The hard coat layer 12 is provided on the transparent substrate 11. The hard coat layer 12 is an AG type hard coat layer, and an uneven structure 30 for imparting antiglare properties to the optical layered body 10 is formed on the surface of the hard coat layer 12. The hard coat layer 12 is composed of a resin such as a cured product of a resin composition. The resin constituting the hard coat layer 12 is not particularly limited, and examples thereof include: an energy ray curable resin such as an ultraviolet curable resin, an electron beam curable resin, and an infrared curable resin, a thermosetting resin, a thermoplastic resin, a two-liquid hybrid resin, and the like. Among them, an ultraviolet curable resin capable of efficiently forming the hard coat layer 12 by ultraviolet irradiation is preferably used.

Examples of the ultraviolet curable resin include: acrylic, urethane, epoxy, polyester, amide, silicone, and the like. Among them, for example, when the laminated film is used for optical applications, acrylic having high transparency is preferably used.

The acrylic ultraviolet curable resin is not particularly limited, and may be appropriately selected from monofunctional, difunctional, trifunctional or higher-functional acrylic monomers, oligomers, polymer components, and the like in view of hardness, adhesion, processability, and the like. Further, a photopolymerization initiator is blended into the ultraviolet curable resin.

Specific examples of the monofunctional acrylate component include: carboxylic acids (acrylic acid), hydroxy (2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate), alkyl or alicyclic monomers (isobutyl acrylate, t-butyl acrylate, isooctyl acrylate, lauryl acrylate, stearyl acrylate, isobornyl acrylate, cyclohexyl acrylate), other functional monomers (2-methoxyethyl acrylate, methoxyethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, ethylcarbyl acrylate, phenoxyethyl acrylate, N-dimethylaminoethyl acrylate, N-dimethylaminopropyl acrylamide, N-dimethylacrylamide, acryloylmorpholine, N-isopropylacrylamide, N-diethylacrylamide, N-vinylpyrrolidone, 2- (perfluorooctyl) ethyl acrylate, 3-perfluorohexyl-2-hydroxypropyl acrylate, 3-perfluorooctyl-2-hydroxypropyl acrylate, 2- (perfluorodecyl) ethyl acrylate, 2- (fluoro-butyl) acrylate, 3-perfluoro-2, 6-bromoethyl acrylate, 2, 6-bromophenol, 2, 6-tribromoethyl acrylate, 2, 4-bromophenol acrylate, and the like.

Specific examples of the difunctional acrylate component include: polyethylene glycol (600) diacrylate, dimethylol-tricyclodecane diacrylate, bisphenol AEO modified diacrylate, 1, 9-nonanediol diacrylate, 1, 10-decane diol diacrylate, propoxylated bisphenol A diacrylate, tricyclodecane dimethanol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, 1, 4-butanediol diacrylate, polyethylene glycol (200) diacrylate, tetraethylene glycol diacrylate, polyethylene glycol (400) diacrylate, cyclohexane dimethanol diacrylate, aliphatic urethane acrylate, polyether urethane acrylate, and the like. Specific examples of such a commercially available product include the trade name "SR610" of Sartomer (Inc.).

Specific examples of the trifunctional or higher acrylate component include: pentaerythritol triacrylate (PETA), 2-hydroxy-3-acryloxypropyl methacrylate, isocyanuric acid EO-modified triacrylate, epsilon-caprolactone-modified tris- (2-acryloxyethyl) isocyanurate, trimethylolpropane triacrylate (TMPTA), epsilon-caprolactone-modified tris (acryloxyethyl) acrylate, tris- (2-acryloxyethyl) isocyanurate, and the like. Specific examples of such commercially available products include the trade name "CN968" of Sartomer and the trade name "SR444" of Sartomer.

Specific examples of the photopolymerization initiator include: an alkylbenzene-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, a titanocene-based photopolymerization initiator, and the like. Specific examples of commercially available products include 1-hydroxycyclohexyl phenyl ketone (IRGACURE 184, BASF JAPAN, inc.), and the like.

In addition, in order to improve the smoothness, the acrylic ultraviolet curable resin preferably contains a leveling agent. Specific examples of the leveling agent include: one or two or more of silicone leveling agents, fluorine leveling agents, acrylic leveling agents, and the like may be used. Among them, from the viewpoint of film coating properties, a silicone leveling agent is preferably used. Specific examples of the commercially available products include BYK337 (polyether modified polydimethylsiloxane) which is a product of BYK-Chemie Japan.

The solvent used for the acrylic ultraviolet curable resin is not particularly limited as long as it satisfies the coatability of the resin composition, but is preferably selected in consideration of safety. Specific examples of the solvent include: propylene glycol monomethyl ether acetate, butyl acetate, methyl 3-ethoxypropionate, ethyl cellosolve acetate, ethyl lactate, methyl 3-methoxypropionate, 2-heptanone, cyclohexanone, ethyl carbitol acetate, butyl carbitol acetate, propylene glycol methyl ether, and the like, and one or two or more of them may be used. Among them, propylene glycol monomethyl ether acetate and butyl acetate are preferably used from the viewpoint of coatability. The acrylic ultraviolet curable resin may contain, in addition to the photopolymerization initiator, the leveling agent, and the solvent, a color phase adjuster, a colorant, an ultraviolet absorber, an antistatic agent, various thermoplastic resin materials, a refractive index adjusting resin, refractive index adjusting particles, and a functional imparting agent such as an adhesion imparting resin.

The resin of the hard coat layer 12 may contain fine metal oxide particles (not shown) dispersed therein. The metal oxide fine particles contained in the hard coat layer 12 of the present embodiment are nano-sized fine particles (average particle diameter smaller than 1 μm) having a particle diameter smaller than that of the filler particles, unlike the conventional micro-sized filler particles (average particle diameter of 1 μm or more) for forming a protrusion-like structure described in the above patent documents 1 and 2. By incorporating nano-sized metal oxide fine particles in the hard coat layer 12, the adhesion between the hard coat layer 12 and the adhesion layer 13 can be improved.

The metal oxide fine particles are formed by forming metal oxide into particles. The average particle diameter of the metal oxide fine particles is preferably 800nm or less, more preferably 20nm or more and 100nm or less. If the average particle diameter of the metal oxide fine particles is excessively larger than 800nm, it is difficult to use the laminated film for optical applications. On the other hand, if the average particle diameter of the metal oxide fine particles is excessively smaller than 20nm, the adhesion between the hard coat layer 12 and the adhesion layer 13 is reduced. Accordingly, when the average particle diameter of the metal oxide fine particles of the present embodiment is within the above-described range, the optical laminate 10 can be preferably used for optical applications, and the adhesion between the hard coat layer 12 and the adhesion layer 13 can be improved. In the present embodiment, the average particle diameter is a value measured by the BET method.

The content of the metal oxide fine particles is preferably 20 mass% or more and 50 mass% or less with respect to the entire solid content of the resin composition of the hard coat layer 12. If the content of the metal oxide fine particles is too small, the adhesion between the hard coat layer 12 and the adhesion layer 13 is lowered. On the other hand, if the content of the metal oxide fine particles is too large, the bendability or the like of the hard coat layer 12 is lowered. Therefore, by setting the content of the metal oxide fine particles in the present embodiment to the above range, the adhesion between the hard coat layer 12 and the adhesion layer 13 can be improved while suppressing the decrease in the bendability of the hard coat layer 12. The solid component of the resin composition means all components except the solvent, and the liquid monomer component is also contained in the solid component.

Specific examples of the metal oxide constituting the metal oxide fine particles include: siO (SiO) ₂ (silica), al ₂ O ₃ (aluminum oxide), tiO ₂ (titanium dioxide), zrO ₂ (zirconia) CeO ₂ (cerium oxide), mgO (magnesium oxide), znO, ta ₂ O ₅ 、Sb ₂ O ₃ 、SnO ₂ 、MnO ₂ Etc. Among them, for example, when the laminated film is used for optical applications, silica which can give high transparency is preferably used. Specific examples of the commercially available products include the trade name "IPA-ST-L" (silica sol) of Nissan chemical Co., ltd. In addition, functional groups such as acryl groups and epoxy groups may be introduced into the surface of the metal oxide microparticles for the purpose of improving adhesion and affinity with the resin.

The hard coat layer 12 of the present embodiment may contain the above-described nano-sized metal oxide fine particles, but may not contain filler particles having an average particle diameter of 1 μm or more (conventional micro-sized particles for forming a protrusion-like structure described in the above-described patent documents 1 and 2). However, even if the hard coat layer 12 of the present embodiment does not contain filler particles, the surface on the side of the adhesion layer 13 is formed with the uneven structure 30, and therefore, the antiglare property can be imparted to the optical laminate 10 by the uneven structure 30. The constitution of the concave-convex structure 30 of the hard coat layer 12 and the method of forming the concave-convex structure 30 will be described in detail later.

The thickness of the hard coat layer 12 is not particularly limited, and is preferably 0.5 μm or more, more preferably 1 μm or more, for example. When the thickness of the hard coat layer 12 is 0.5 μm or more, sufficient hardness is obtained, and thus scratches in production are less likely to occur. The thickness of the hard coat layer 12 is preferably 100 μm or less. When the thickness of the hard coat layer 12 is 100 μm or less, the optical layered body 10 can be thinned and reduced in weight. Further, when the thickness of the hard coat layer 12 is 100 μm or less, microcracks of the hard coat layer 12 generated when the optical laminate 10 is bent during the production are less likely to occur, and the productivity is improved.

The hard coat layer 12 may be a single layer or a layer formed by stacking a plurality of layers. Further, the hard coat layer 12 may be further provided with known functions such as ultraviolet absorption performance, antistatic performance, refractive index adjustment function, hardness adjustment function, and the like. The function imparted to the hard coat layer 12 may be imparted to a single hard coat layer or may be separately imparted to a plurality of hard coat layers.

[ sealing layer 13]

The adhesion layer 13 is a layer formed to make the hard coat layer 12 as an organic film adhere well to the antireflection layer 14 as an inorganic film. The sealing layer 13 is preferably made of a metal oxide or a metal in an oxygen deficient state. The oxygen-deficient metal oxide refers to a metal oxide in which the number of oxygen atoms is insufficient compared with the stoichiometric composition. Examples of the metal oxide in the anoxic state include: siOx, alOx, tiOx, zrOx, ceOx, mgOx, znOx, taOx, sbOx, snOx, mnOx, etc. Further, as the metal, there may be mentioned: si, al, ti, zr, ce, mg, zn, ta, sb, sn, mn, in, etc. The adhesion layer 13 may be, for example, a layer in which x in SiOx exceeds 0 and is smaller than 2.0. The sealing layer 13 may be formed of a mixture of a plurality of metals or metal oxides.

When the adhesion layer 13 is made of SiOx, the refractive index of the adhesion layer 13 is preferably 1.20 or more and 1.60 or less. That is, when the adhesion layer 13 is made of SiOx, the adhesion layer 13 also functions as a low refractive index layer 14b described later.

The thickness of the adhesion layer 13 is preferably more than 0nm and 20nm or less, particularly preferably 1nm or more and 10nm or less, from the viewpoint of maintaining transparency and adhesion to the antireflection layer 14 and obtaining good optical characteristics.

It is preferable to provide the adhesion layer 13 between the hard coat layer 12 and the antireflection layer 14, because adhesion between the two layers can be improved. However, the sealing layer 13 is not necessarily required, and the antireflection layer 14 may be directly laminated on the hard coat layer 12.

[ antireflection layer 14]

The antireflection layer 14 is an example of a metal oxide layer provided on the hard coat layer 12. The antireflection layer 14 is an example of an optical functional layer. The antireflection layer 14 is a laminate exhibiting an antireflection function. As shown in fig. 1, the antireflection layer 14 is composed of a laminate in which low refractive index layers 14b and high refractive index layers 14a are alternately laminated. In the present embodiment, the antireflection layer 14 is a laminate of four layers in total in which the high refractive index layer 14a and the low refractive index layer 14b are alternately laminated in order from the adhesive layer 13 side. The number of layers of the high refractive index layer 14a and the low refractive index layer 14b is not particularly limited, and the number of layers of the high refractive index layer 14a and the low refractive index layer 14b may be any number.

As shown in fig. 1, the stain-proofing layer 15 is in contact with the low refractive index layer 14b constituting the antireflection layer 14. Therefore, light incident from the stain-proofing layer 15 side is diffused by the antireflection layer 14. This provides an antireflection function of preventing light incident from the antifouling layer 15 side from being reflected in one direction.

The low refractive index layer 14b preferably contains an oxide of Si, preferably in SiO, from the viewpoint of easiness and cost of obtaining ₂ (oxide of Si) and the like as a main component. SiO (SiO) ₂ The single layer film is colorless and transparent. In the present embodiment, the main component of the low refractive index layer 14b means that 50 mass% or more of the component is contained in the low refractive index layer 14 b.

In the case where the low refractive index layer 14b is a layer containing an oxide of Si as a main component, other elements may be contained in an amount of less than 50 mass%. The content of the element other than the oxide of Si is preferably 10% or less. As other elements, na may be contained for the purpose of improving durability, zr, al or N may be contained for the purpose of improving hardness, and Zr and Al may be contained for the purpose of improving alkali resistance, for example.

The refractive index of the low refractive index layer 14b is preferably 1.20 or more and 1.60 or less, more preferably 1.30 or more and 1.50 or less. As the dielectric used for the low refractive index layer 14b, magnesium fluoride (MgF ₂ Refractive index 1.38), and the like.

The refractive index of the high refractive index layer 14a is preferably 2.00 or more and 2.60 or less, more preferably 2.10 or more and 2.45 or less. As the dielectric used for the high refractive index layer 14a, there can be mentioned: niobium pentoxide (Nb) ₂ O ₅ Refractive index 2.33), titanium oxide (TiO ₂ Refractive index of 2.33 or more and 2.55 or less), tungsten oxide (WO ₃ Refractive index 2.2), cerium oxide (CeO) ₂ Refractive index 2.2), tantalum pentoxide (Ta ₂ O ₅ Refractive index 2.16), zinc oxide (ZnO, refractive index 2.1), indium tin oxide (ITO, refractive index 2.06), zirconium oxide (ZrO ₂ Refractive index 2.2), and the like.

In the case where the high refractive index layer 14a is to be provided with conductive properties, for example, ITO or Indium Zinc Oxide (IZO) may be selected.

For example, niobium pentoxide (Nb) is preferably used as the antireflection layer 14 ₂ O ₅ A layer having a refractive index of 2.33) was used as the high refractive index layer 14a, and a layer made of SiO ₂ The layer is constituted as the low refractive index layer 14b.

The film thickness of the low refractive index layer 14b may be in the range of 1nm to 200nm, and may be appropriately selected depending on the wavelength region in which the antireflection function is required.

The film thickness of the high refractive index layer 14a may be, for example, 1nm or more and 200nm or less, and may be appropriately selected according to the wavelength region in which the antireflection function is required.

The film thicknesses of the high refractive index layer 14a and the low refractive index layer 14b may be appropriately selected according to the design of the antireflection layer 14, respectively. For example, the sealing layer 13 may be provided with a high refractive index layer 14a of 5nm or more and 50nm or less, a low refractive index layer 14b of 10nm or more and 80nm or less, a high refractive index layer 14a of 20nm or more and 200nm or less, and a low refractive index layer 14b of 50nm or more and 200nm or less in this order.

Among the layers forming the antireflection layer 14, the low refractive index layer 14b is arranged on the side of the antireflection layer 15. When the low refractive index layer 14b of the antireflection layer 14 is in contact with the stain-proofing layer 15, the antireflection performance of the antireflection layer 14 is preferable.

In the present embodiment, the optical functional layer provided on the hard coat layer 12 is exemplified as the antireflection layer 14, but the optical functional layer is not limited to the example. The optical functional layer is a layer that embodies an optical function. The optical function means a function of controlling reflection, transmission, and refraction, which are properties of light, and examples thereof include: antireflection function, selective reflection function, antiglare function, lens function, etc. The optical functional layer may be, for example, a selective reflection layer, an antiglare layer, or the like, in addition to the antireflection layer 14 described above. As the selective reflection layer and the antiglare layer, known selective reflection layers and antiglare layers can be used. The antireflection layer, the selective reflection layer, and the antiglare layer may be a single layer or a laminate of a plurality of layers.

[ antifouling layer 15]

The anti-fouling layer 15 is formed on the outermost surface of the anti-reflection layer 14, preventing fouling of the anti-reflection layer 14. Further, when the stain-proofing layer 15 is applied to a touch panel or the like, wear of the anti-reflection layer 14 is suppressed by abrasion resistance.

The antifouling layer 15 of the present embodiment is formed of a vapor deposited film formed by vapor deposition of an antifouling material. In the present embodiment, the antifouling layer 15 is formed by vacuum vapor deposition of a fluorine-based organic compound as an antifouling material on one surface of the low refractive index layer 14b constituting the antireflection layer 14. In the present embodiment, the antifouling material contains a fluorine-based organic compound, and thus becomes the optical laminate 10 having further excellent abrasion resistance and alkali resistance.

As the fluorine-based organic compound constituting the antifouling layer 15, a compound containing a fluorine-modified organic group and a reactive silane group (for example, alkoxysilane) is preferably used. The fluorine-based organic compound constituting the antifouling layer 15 is, for example, a silane compound having a fluoroalkyl chain or an alkoxysilane compound having a perfluoropolyether group. Examples of the commercial products include OPTOOL DSX (manufactured by Dain Co., ltd.), KY-100 series (manufactured by Xinyue chemical Co., ltd.), and the like.

By using an alkoxysilane compound having a perfluoropolyether group as the fluorine-based organic compound constituting the antifouling layer 15, the contact angle of the antifouling layer 15 with water can be made 110 degrees or more, and the hydrophobicity and antifouling property can be improved.

As the fluorine-based organic compound constituting the antifouling layer 15, a compound containing a fluorine-modified organic group and a reactive silane group (for example, alkoxysilane) is used, and SiO ₂ In the case of the low refractive index layer 14b of the antireflection layer 14 in contact with the stain-proofing layer 15, the silanol group and SiO which are the skeleton of the fluorine-based organic compound are formed as layers ₂ And forms siloxane bonds therebetween. Therefore, the adhesion between the antireflection layer 14 and the stain-proofing layer 15 becomes good, which is preferable.

The optical thickness of the stain-proofing layer 15 is not less than 1nm and not more than 20nm, preferably not less than 3nm and not more than 10 nm. When the thickness of the antifouling layer 15 is 1nm or more, abrasion resistance can be sufficiently ensured when the optical laminate 10 is applied to a touch panel or the like. Further, when the thickness of the antifouling layer 15 is 20nm or less, the time required for vapor deposition is short, and efficient production can be achieved.

The antifouling layer 15 may contain additives such as a light stabilizer, an ultraviolet absorber, a colorant, an antistatic agent, a lubricant, a leveling agent, a defoaming agent, an antioxidant, a flame retardant, an infrared absorber, and a surfactant, as necessary.

The anti-fouling layer 15 formed by vapor deposition is firmly bonded to the anti-reflection layer 14, and has a small number of voids and is dense. Thus, the stain-proofing layer 15 of the present embodiment exhibits characteristics different from those of the stain-proofing layer formed by the conventional method such as coating of the stain-proofing material.

[2 ] concave-convex Structure 30 of hard coating layer 12 ]

Next, the concave-convex structure of the hard coat layer 12 according to the present embodiment will be described with reference to fig. 1 to 4.

Fig. 2 is a cross-sectional view showing an example of the hard coat layer 12 according to the present embodiment. As shown in fig. 2, the hard coat layer 12 of the present embodiment has a surface on the side of the adhesion layer 13 formed with a concave-convex structure 30. The concave-convex structure 30 is composed of a plurality of convex portions 32 and a plurality of concave portions 34. The top portions 32a of the plurality of projections 32 constituting the concave-convex structure 30 of the hard coat layer 12 have substantially the same height as each other, and furthermore, the top portions 32a each have a substantially flat face. In addition, the plurality of concave portions 34 constituting the concave-convex structure 30 of the hard coat layer 12 do not penetrate the hard coat layer 12. That is, the bottom 34a of the recess 34 of the hard coat layer 12 is not in contact with the surface of the transparent substrate 11.

As described above, the thickness of the adhesion layer 13 (for example, about 0.005 μm), the thickness of the antireflection layer 14 (for example, about 0.2 μm), and the thickness of the antifouling layer 15 (for example, about 0.005 μm) are significantly smaller than the thickness of the hard coat layer 12 (for example, 5 μm or more and 10 μm or less). Therefore, the adhesion layer 13, the anti-reflection layer 14, and the stain-proofing layer 15 are formed to follow the uneven structure 30 of the hard coat layer 12.

Therefore, as shown in fig. 1, the surface of the adhesion layer 13 is an uneven surface 40 that follows the shape of the uneven structure 30 of the hard coat layer 12. Accordingly, the top portions of the plurality of convex portions constituting the concave-convex surface 40 of the adhesion layer 13 have substantially the same height as the top portions 32a of the convex portions 32 of the hard coat layer 12, and the top portions have substantially flat surfaces.

Similarly, the surfaces of the antireflection layer 14, that is, the surface of the high refractive index layer 14a and the surface of the low refractive index layer 14b become concave-convex surfaces 50a, 50b following the shape of the concave-convex structure 30 of the hard coat layer 12. Accordingly, the top portions of the plurality of projections constituting the concave-convex surface 50a of the high refractive index layer 14a and the top portions of the plurality of projections constituting the concave-convex surface 50b of the low refractive index layer 14b have substantially the same height as the top portions 32a of the projections 32 of the hard coat layer 12, and the top portions have substantially flat surfaces, respectively.

The surface of the stain-proofing layer 15, that is, the outermost surface of the optical laminate 10, is an uneven surface 60 which follows the shape of the uneven structure 30 of the hard coat layer 12. Therefore, the concave-convex surface 60 formed on the outermost surface of the optical laminate 10 is composed of a plurality of convex portions 62 and a plurality of concave portions 64. Therefore, the plurality of convex portions 62 constituting the concave-convex surface 60 have the same shape as the plurality of convex portions 32 of the hard coat layer 12. That is, the top portions 62a of the plurality of projections 62 constituting the uneven surface 60 have substantially the same height as the top portions 32a of the projections 32 of the hard coat layer 12, and the top portions 62a each have a substantially flat surface. The plurality of concave portions 64 constituting the concave-convex surface 60 have the same shape as the plurality of concave portions 34 of the hard coat layer 12.

Fig. 3 is a view showing a 3D image of an example of the optical layered body 10 according to the present embodiment. Fig. 4 is a view showing a cross-sectional roughness of an example of the optical laminate 10 according to the present embodiment.

As shown in fig. 3, the outermost surface of the optical laminate 10 is an uneven surface 60 composed of a plurality of convex portions 62 and a plurality of concave portions 64. In the concave-convex surface 60, the plurality of convex portions 62 are formed in a floating island shape which is arranged to be randomly dispersed in the surface direction. Each of the convex portions 62 has a substantially truncated cone shape, but the planar shape of the convex portion 62 is random. Similarly, the plurality of convex portions 32 constituting the concave-convex structure 30 of the hard coat layer 12 are also formed in a floating island shape which is randomly dispersed in the planar direction.

The top portions 62a of the plurality of convex portions 62 constituting the concave-convex surface 60 of the optical laminate 10 have substantially the same height as each other. Therefore, it can also be said that the top portions 32a of the plurality of convex portions 32 constituting the concave-convex structure 30 of the hard coat layer 12 have substantially the same height as each other. Here, the "substantially the same height" means a structure in which, for example, as shown in fig. 4, the heights of the plurality of projections 62 formed on the surface of the optical laminate 10 are substantially equal, and thus the stress can be uniformly dispersed against a load generated by an object in contact with the optical laminate 10, for example, an operator's finger, a stylus (pointing device), or the like. In the case where the heights of the top portions 62a of the plurality of projections 62 have "substantially the same height as each other", the unevenness in height of the top portions 62a of the plurality of projections 62 (i.e., the difference in height of the plurality of top portions 62 a) is desirably within 0.5 μm, more desirably within 0.2 μm. Similarly, in the case where the heights of the top portions 32a of the plurality of convex portions 32 have "substantially the same height as each other", the unevenness of the heights of the top portions 32a of the plurality of convex portions 32 (i.e., the height difference of the plurality of top portions 32 a) is desirably within 0.5 μm, and more desirably within 0.2 μm.

Further, the top portions 62a of the plurality of convex portions 62 constituting the concave-convex surface 60 of the hard coat layer 12 each preferably further have a substantially flat surface (top surface). Here, the term "substantially flat surface" means a flat surface having fine irregularities formed therein, in addition to a complete flat surface of the top 62a including the convex portion 62. The flat surface on which the fine irregularities are formed is, for example, a flat surface having a height difference of ±0.3 μm or less, preferably ±0.1 μm or less, with respect to the reference surface of the top 62 a. The reference surface is a completely flat surface virtually set at a desired height position of the convex portion 62.

Similarly, the top portions 32a of the plurality of convex portions 32 constituting the concave-convex structure 30 of the optical laminate 10 each preferably further have a substantially flat surface (top surface). Here, the term "substantially flat surface" means a surface having a flat surface formed with fine irregularities in addition to a surface having a completely flat surface at the top 32a including the convex portion 32. The flat surface on which the fine irregularities are formed is, for example, a flat surface having a height difference of ±0.3 μm or less, preferably ±0.1 μm or less, with respect to the reference surface of the top portion 32 a. The reference surface is a completely flat surface virtually set at a desired height position of the convex portion 32.

As shown in fig. 3, in the concave-convex surface 60 of the optical laminate 10, the plurality of concave portions 64 are scattered randomly in the surface direction. Each concave portion 64 is, for example, a concave portion having a random planar shape, and the depth of the bottom portion 64a of the concave portion 64 is also random. Similarly, the plurality of concave portions 34 constituting the concave-convex structure 30 of the hard coat layer 12 are also scattered randomly in the planar direction, the planar shape of each concave portion 34 is also random, and the depth of the bottom portion 34a of the concave portion 34 is also random.

As shown in fig. 4, in the concave-convex surface 60 of the optical laminate 10, the height difference between the top 62a of the convex portion 62 and the bottom 64a of the concave portion 64 is, for example, about 0.4 μm or more and 1 μm or less. Similarly, in the uneven structure 30 of the hard coat layer 12, the height difference between the top 32a of the convex portion 32 and the bottom 34a of the concave portion 34 is, for example, also about 0.4 μm or more and 1 μm or less.

In this way, the hard coat layer 12 has the concave-convex structure 30, that is, the concave-convex surface 60 is formed on the outermost surface of the optical laminate 10. As a result, the incident light is scattered by the concave-convex surface 60 of the optical laminate 10, and thus the optical laminate 10 can exhibit antiglare properties.

The height distribution of the surface of the uneven structure 30 of the hard coat layer 12 of the present embodiment satisfies the following expression (1).

A/1.9<P……(1)

A: when the height B of the lowest point of the surface of the concave-convex structure 30 is set to 0, the height of the highest point of the surface of the concave-convex structure 30.

P: when the height B of the lowest point of the surface of the concave-convex structure 30 is set to 0, the mode of the height distribution of the surface of the concave-convex structure 30 is set.

In other words, P is the maximum point of the distribution when the height distribution of the surface of the concave-convex structure 30 is represented by a histogram.

In the case where the above formula (1) is satisfied, in the concave-convex structure 30 of the hard coat layer 12, the convex portions 32 having the substantially flat top portions 32a are distributed much more than the convex portions having the top portions protruding in a hammer shape or a hill shape, the distribution area of the flat top portions 32a is wide, and the heights of the flat top portions 32a are substantially uniform. Therefore, the uneven structure 30 has a rough surface structure including a large number of the top portions 32a formed of flat surfaces, and is excellent in scratch resistance. On the other hand, when the above formula (1) is not satisfied, that is, when A/1.9. Gtoreq.P, the convex-concave structure of the hard coat layer has a large distribution of convex portions protruding into hammer-like or hilly-like top portions, and the distribution area of flat top portions becomes narrow. Therefore, the uneven structure has a protrusion-like structure with sharp protrusions, and the scratch resistance is reduced.

As described above, the outermost surface of the optical layered body 10 according to the present embodiment is the uneven surface 60 formed to follow the shape of the uneven structure 30 of the hard coat layer 12, the top portions 62a of the plurality of convex portions 62 constituting the uneven surface 60 have substantially the same height as each other, and the top portions 62a of the plurality of convex portions 62 each have substantially flat surfaces.

Therefore, a protrusion-like structure having a protrusion shape protruding in a hillock shape or a tapered shape as in the conventional technique is hardly formed on the outermost surface of the optical laminate 10. Therefore, the surface of the optical laminate 10 of the present embodiment has a mesa-like rough surface structure in which the top 62a of the convex portion 62 is a substantially flat surface. Thus, for example, when the optical layered body 10 is provided as an antireflection film on a touch panel, a load applied to the surface screen by an operator's finger, pointing device, or the like can be dispersed at the top 62a of the convex portion 62. Therefore, compared with the conventional optical laminate having a protrusion-like structure with protrusions protruding in a hillock shape or a tapered shape, the optical laminate 10 can suppress abrasion of the convex portion 62 and can improve scratch resistance. This can improve the durability of the optical laminate 10.

[3 ] Properties of the optical laminate 10 ]

Next, characteristics of the optical laminate 10 of the present embodiment will be described. The optical laminate 10 of the present embodiment has, for example, the following characteristics (a) to (C).

(A) Water contact angle (WCA Water Contact Angle)

Consider the case where the following friction test is performed: according to JIS L0849, a friction tester using steel wool was used to load steel wool: 1kg, contact area: 1 cm. Times.1 cm, reciprocating: the surface of the optical laminate 10 was rubbed 2000 times. In the optical laminate 10 of the present embodiment, the contact angle of the outermost surface of the optical laminate 10 after the friction test to water is preferably 90 degrees or more.

In the case where a projection-like structure having sharp projections as in the conventional technique is formed on the outermost surface of the optical laminate, the projections are ground by sliding of the wire wool, and chipping is generated. In this way, since the friction test is continued with the shavings interposed between the steel wool and the optical laminate, the antireflection layer and the antifouling layer are both ground from the hard coat layer. In this case, the stain-proofing layer is removed from the outermost surface of the optical laminate, so that the outermost surface of the optical laminate 10 is easily wetted, and the contact angle with water after the rubbing test is less than 90 degrees. That is, when the contact angle with water after the rubbing test is smaller than 90 degrees, it can be said that the convex portions 62 constituting the concave-convex surface 60 of the optical laminate 10 are ground together with the anti-fouling layer 15 and the scratch resistance is low by performing the rubbing test.

In contrast, the optical laminate 10 of the present embodiment has the following characteristics: even after the friction test described above is performed, the contact angle of the outermost surface of the optical layered body 10 after friction against water is 90 degrees or more. Therefore, even if the friction test is performed on the optical laminate 10 of the present embodiment, the convex portions 62 (the stain-proofing layer 15) constituting the concave-convex surface 60 of the optical laminate 10 are hardly ground. As a result, the uneven surface 60 of the optical laminate 10 of the present embodiment is less likely to be damaged, and is excellent in scratch resistance.

(B) Surface roughness Sa

The surface roughness Sa of the concave-convex structure 30 of the hard coat layer 12 is preferably 50nm or more and 300nm or less. The surface roughness Sa refers to an arithmetic mean height Sa (ISO 25178).

If the surface roughness Sa is less than 50nm, there is a problem that sufficient antiglare properties cannot be exhibited, and if the surface roughness Sa exceeds 300nm, there is a problem that it is difficult to make the top portions 62a of the plurality of projections 62 substantially the same height as each other, and sufficient scratch resistance cannot be achieved. In contrast, the surface roughness Sa of the uneven structure of the hard coat layer 12 of the optical laminate 10 of the present embodiment is 50nm or more and 300nm or less, and therefore antiglare properties and scratch resistance can be preferably achieved.

(C) External Haze value (Haze)

The external haze value of the optical laminate 10 according to the present embodiment is preferably 3% or more and 40% or less, which is defined in JIS K7136. The external haze value is a value obtained by digitizing the proportion of the diffuse light component in the total light transmittance. The external haze value is obtained by subtracting the scattering component inside the sample (optical laminate 10) from the haze value specified in JIS K7136.

If the external haze value of the optical laminate is less than 3%, the antiglare property cannot be sufficiently exhibited, and if the external haze value of the optical laminate exceeds 40%, the reproducibility of black and the vividness of an image at the time of displaying the image become low. In contrast, the optical laminate 10 of the present embodiment has an external haze value of 3% or more and 40% or less, and thus can preferably achieve antiglare properties and a high image display quality level.

As described above, the hard coat layer 12 of the optical layered body 10 of the present embodiment has the micro-scale concave-convex structure 30. Thus, the optical laminate 10 of the present embodiment can exhibit antiglare properties. The uneven structure 30 of the hard coat layer 12 of the present embodiment is formed by transfer using a transfer mold described later, and is not formed by containing filler particles as in the conventional art. Accordingly, the top portions 32a of the plurality of convex portions 32 constituting the concave-convex structure 30 of the present embodiment have substantially the same height as each other, and the top portions 32a of the plurality of convex portions 32 each have a substantially flat surface. Accordingly, the top portions 62a of the plurality of convex portions 62 also have substantially the same height as each other in the concave-convex surface 60 of the outermost surface of the optical laminate 10, and the top portions 62a of the plurality of convex portions 62 each have a substantially flat surface, and there are no protruding convex portions in the protruding shape, so that the scratch resistance of the optical laminate 10 is improved. Thus, the optical laminate 10 can maintain antiglare properties and improve scratch resistance.

[4 ] method for producing optical laminate 10]

Fig. 5 is a flowchart showing a method of manufacturing the optical layered body 10 according to the present embodiment.

As shown in fig. 5, the method for manufacturing the optical laminate 10 according to the present embodiment includes a hard coat layer forming step S110, an adhesion layer forming step S120, an antireflection layer forming step S130, and an antifouling layer forming step S140. Hereinafter, each step will be described.

[ hard coating Forming Process S110]

The hard coat layer forming step S110 is a step of providing the hard coat layer 12 on the transparent base material 11.

In the present embodiment, the hard coat layer forming step S110 includes a coating step S112 and a transfer step S114. In the transfer step S114 of the hard coat layer forming step S110, the concave-convex structure 30 is transferred to the surface of the hard coat layer 12 using a transfer mold. First, a method for manufacturing a transfer mold according to the present embodiment will be described with reference to fig. 6. Next, the coating step S112 and the transfer step S114 will be described with reference to fig. 7.

Fig. 6 is a process diagram illustrating an example of a method for manufacturing the transfer mold 150 according to the present embodiment. In fig. 6, black circles indicate filler particles 120, and white circles indicate solvent 112. As shown in fig. 6, first, a resin 100 for a transfer mold is produced. The resin 100 is, for example, a resin in which filler particles 120 are dispersed in a binder resin 110. The binder resin 110 constituting the resin 100 is not particularly limited, and is preferably a transparent resin that transmits energy rays such as ultraviolet rays, infrared rays, and electron beams, and for example, an energy ray curable resin, a thermoplastic resin, a thermosetting resin, or the like, which is a resin cured by ultraviolet rays, infrared rays, or electron beams, can be used.

The energy ray curable resin used for the binder resin 110 includes: ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methyl styrene, N-vinylpyrrolidone, carboxylic acids (acrylic acid), hydroxyl groups (2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate), alkyl or alicyclic monomers (isobutyl acrylate, tert-butyl acrylate, isooctyl acrylate, lauryl acrylate, stearyl acrylate, isobornyl acrylate, cyclohexyl acrylate), other functional monomers (2-methoxyethyl acrylate, methoxyethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, ethylcarbitol acrylate, phenoxyethyl acrylate, N-acrylate, N-dimethylaminoethyl acrylate, N-dimethylaminopropyl acrylamide, N-dimethylacrylamide, acryloylmorpholine, N-isopropylacrylamide, N-diethylacrylamide, 2- (perfluorooctyl) ethyl acrylate, 3-perfluorohexyl-2-hydroxypropyl acrylate, 3-perfluorooctyl-2-hydroxypropyl acrylate, 2- (perfluorodecyl) ethyl acrylate, 2- (perfluoro-3-methylbutyl) ethyl acrylate, 2,4, 6-tribromophenol methacrylate, 2- (2, 4, 6-tribromophenoxy) ethyl acrylate, 2-ethylhexyl acrylate, nonylphenol EO modified acrylate, and the like.

The energy ray curable resin having two or more unsaturated bonds may be, for example: trimethylolpropane tri (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, tripentaerythritol octa (meth) acrylate, tetrapentaerythritol deca (meth) acrylate, tris (meth) isocyanurate, di (meth) isocyanurate, polyester tri (meth) acrylate, polyester di (meth) acrylate, bisphenol di (meth) acrylate, diglycerol tetra (meth) acrylate, adamantyl di (meth) acrylate, isobornyl di (meth) acrylate, dicyclopentane di (meth) acrylate, tricyclodecane di (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, polyethylene glycol (600) diacrylate, dimethylol-tri (meth) acrylate, bisphenol AEO modified di (AEO) acrylate, and polyfunctional compounds such as 1, 9-nonyleneglycol diacrylate, 1, 10-decaneglycol diacrylate, propoxylated bisphenol A diacrylate, tricyclodecane dimethanol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, 1, 4-butanediol diacrylate, polyethylene glycol (200) diacrylate, tetraethylene glycol diacrylate, polyethylene glycol (400) diacrylate, cyclohexanedimethanol diacrylate, aliphatic urethane acrylate, polyether urethane acrylate, 2-hydroxy-3-acryloxypropyl methacrylate, isocyanuric acid EO-modified triacrylate, epsilon-caprolactone-modified tris- (2-acryloxyethyl) isocyanurate, trimethylolpropane triacrylate (TMPTA), epsilon-caprolactone-modified tris (acryloxyethyl) acrylate, and tris- (2-acryloxyethyl) isocyanurate. Among them, pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), and pentaerythritol tetraacrylate (PETTA) are preferably used. The "(meth) acrylate" refers to both methacrylate and acrylate. As the energy ray curable resin, a resin obtained by modifying the above compound with PO (propylene oxide), EO (ethylene oxide), CL (caprolactone) or the like can be used.

Examples of the thermoplastic resin used for the binder resin 110 include: styrene-based resins, (meth) acrylic resins, vinyl acetate-based resins, vinyl ether-based resins, halogen-containing resins, alicyclic olefin-based resins, polycarbonate-based resins, polyester-based resins, polyamide-based resins, cellulose derivatives, silicone-based resins, rubbers or elastomers, and the like. The thermoplastic resin is preferably amorphous and soluble in an organic solvent (particularly, a common solvent capable of dissolving a plurality of polymers and curable compounds). In particular, from the viewpoints of transparency and weather resistance, styrene resins, (meth) acrylic resins, alicyclic olefin resins, polyester resins, cellulose derivatives (cellulose esters and the like) and the like are preferable.

Examples of the thermosetting resin used for the binder resin 110 include: phenolic resins, urea resins, diallyl phthalate resins, melamine resins, guanamine resins, unsaturated polyester resins, polyurethane resins, epoxy resins, amino alkyd resins, melamine-urea copolycondensation resins, silicone resins (so-called silsequioxanes including cages, ladders, etc.), and the like.

Here, as the binder resin 110, an ultraviolet curable resin is exemplified. Further, a photopolymerization initiator is blended in the ultraviolet curable resin.

As the filler particles 120 contained in the binder resin 110, for example, known particles such as particles composed of inorganic oxides such as silica (Si oxide) particles and bauxite (alumina) particles, or organic particles can be used. The average particle diameter of the inorganic oxide particles such as silica particles and bauxite particles as the filler particles 120 is not particularly limited, but is preferably 0.5 μm or more and 10 μm or less, and more preferably 1 μm or more and 5 μm or less.

The organic particles as the filler particles 120 include, for example, acrylic resins and the like. The particle diameter of the organic particles is not particularly limited, but is preferably 0.5 μm or more and 10 μm or less, more preferably 1 μm or more and 5 μm or less.

When the resin 100 is applied to the mold base 130 described later, the content of the binder resin 110 in the resin 100 is adjusted to be very small so that the filler particles 120 are not buried in the binder resin 110.

Then, the produced resin 100 is coated on the surface 130a of the mold base 130. The mold base 130 is formed of, for example, a material that transmits ultraviolet rays. The mold base 130 may be formed of, for example, the same organic material or inorganic material as the transparent base 11. The surface 130a of the mold substrate 130 to which the resin 100 is applied is substantially flat. Here, "substantially flat" means that the surface 130a of the mold base 130 does not have a substantial level difference in its entirety, for example, the level difference in the entirety of the surface 130a of the mold base 130 is preferably within 0.5 μm, more preferably within 0.2 μm. Further, fine irregularities may be formed on the surface 130a of the mold base 130. The level difference of the fine irregularities formed on the surface 130a may be ±0.3 μm or less, preferably ±0.1 μm or less, with respect to the reference plane of the surface 130 a. The reference plane is a completely flat plane virtually set at a desired height position of the surface 130 a.

Then, the resin 100 applied to the mold base 130 is dried, and the resin 100 is irradiated with ultraviolet rays, so that the ultraviolet-curable resin, which is the binder resin 110 contained in the resin 100, is cured. In this way, the solvent 112 contained in the resin 100 is gasified, and the binder resin 110 is coagulated around the filler particles 120.

In this way, a transfer mold 150 is manufactured in which filler particles 120 covered with the binder resin 110 are dispersed on the surface 130a of the mold base 130. The filler particles 120 covered with the binder resin 110 are formed as protrusions protruding in any shape such as a hillock shape or a hammer shape on the surface 130a of the mold base 130. Hereinafter, the filler particles 120 covered with the binder resin 110 will be simply referred to as "protrusions 140". The plurality of protrusions 140 are formed separately from each other on the flat surface 130a of the mold base 130. Between adjacent protrusions 140, the flat surface 130a of the mold base 130 is exposed. In this way, the transfer mold 150 having the concave-convex shape 152 composed of the plurality of convex portions 142 and the plurality of concave portions 132 is manufactured. The convex portion 142 of the concave-convex shape 152 is constituted by the protrusion 140, and the bottom of the concave portion 132 is the flat surface 130a of the mold base 130.

[ coating Process S112]

Next, the coating step S112 and the transfer step S114 shown in fig. 5 will be described with reference to fig. 7. Fig. 7 is a process diagram illustrating the coating process S112 and the transfer process S114 of the present embodiment. The coating step S112 is, for example, a step of coating the surface of the transparent substrate 11 with the energy ray curable resin composition 70. The energy ray-curable resin composition 70 contains an uncured energy ray-curable resin, an energy ray polymerization initiator, and metal oxide microparticles.

The thickness (film thickness) of the energy ray curable resin composition 70 applied to the surface of the transparent substrate 11 is larger than the height of the protrusions 140 (protrusions 142) of the transfer mold 150 shown in fig. 6.

[ transfer Process S114]

The transfer step S114 is a step of transferring the concave-convex shape 152 of the transfer mold 150 to the energy ray curable resin composition 70. Specifically, the concave-convex shape 152 of the transfer mold 150 is first pressed against the energy ray-curable resin composition 70. Then, the energy ray is irradiated to cure the energy ray curable resin composition 70. As described above, the transfer mold 150 has transparency allowing transmission of energy rays. Therefore, by pressing the concave-convex shape 152 of the transfer mold 150 against the energy ray-curable resin composition 70 and irradiating the energy ray, the concave-convex shape 152 of the transfer mold 150 can be transferred to the energy ray-curable resin composition 70 and the energy ray-curable resin composition 70 can be cured.

Then, when the transfer mold 150 is peeled off from the cured energy ray-curable resin composition 70, the hard coat layer 12 having the concave-convex structure 30 is formed. The relief structure 30 of the hard coat layer 12 has an inverted shape of the relief shape 152 of the transfer mold 150. Specifically, the convex portions 32 of the concave-convex structure 30 constituting the hard coat layer 12 have a shape corresponding to the concave portions 132 of the concave-convex shape 152 of the transfer mold 150. The concave portions 34 of the concave-convex structure 30 constituting the hard coat layer 12 have a shape corresponding to the convex portions 142 (the protrusions 140) of the concave-convex shape 152 of the transfer mold 150.

Further, as described above, the surface 130a of the mold base 130 of the transfer mold 150 is substantially flat. Therefore, by transferring the concave-convex shape 152 of the transfer mold 150, the top portions 32a of the plurality of convex portions 32 constituting the concave-convex structure 30 of the hard coat layer 12 also have substantially the same height as each other. As described above, the height difference of the fine irregularities on the surface 130a of the mold base 130 of the transfer mold 150 is ±0.3 μm or less with respect to the reference surface of the surface 130 a. Therefore, by transferring the concave-convex shape 152 of the transfer mold 150, the top portions 32a of the plurality of convex portions 32 constituting the concave-convex structure 30 of the hard coat layer 12 also each have a substantially flat surface.

The concave-convex shape 152 of the transfer mold 150 is adjusted according to the desired shape of the concave-convex structure 30 of the hard coat layer 12. Specifically, when the transfer mold 150 is manufactured, the particle diameter of the filler particles 120, the content of the filler particles 120, and the like contained in the resin 100 are adjusted according to the desired shape of the concave-convex structure 30. For example, if the convex portions 32 of the concave-convex structure 30 of the hard coat layer 12 are to be enlarged, the content of the filler particles 120 may be reduced. In the case of reducing the convex portions 32 of the concave-convex structure 30 of the hard coat layer 12, the content of the filler particles 120 may be increased. In addition, in the case where the height of the convex portion 32 and the depth of the concave portion 34 of the concave-convex structure 30 of the hard coat layer 12 are to be increased, the particle diameter of the filler particles 120 may be increased. In the case where the height of the convex portion 32 and the depth of the concave portion 34 of the hard coat layer 12 are to be reduced, the particle diameter of the filler particles 120 may be reduced.

In order to reduce peeling of the transfer mold 150 and to protect the shape of the surface, a layer (not shown) may be further provided on the surface of the transfer mold 150 (the surface 130a between the filler particles 120 covered with the binder resin 110) as needed. As an example of the layer, an inorganic layer and an antifouling layer are listed in order from the binder resin 110 side. The stain-proofing layer improves the peelability when peeling after transferring the shape to the energy ray-curable resin composition 70 (hard coat layer 12). In addition, the inorganic layer has a function of making the stain-proofing layer more firmly bonded to the transfer mold 150. Here, the inorganic layer may be formed by a sputtering method or a vapor deposition method, and the number of layers may be arbitrarily set. The material of the stain-proofing layer is not limited as long as it has an effect of improving the releasability from the hard coat layer 12, and examples thereof include silane compounds having a fluorine-containing group such as a fluoroalkyl group. The method for forming the antifouling layer may be, for example, a coating drying method or a vapor deposition method. That is, in the case where the target shape can be transferred to the hard coat layer 12, another optical laminate having a shape corresponding to the desired shape may be used as the transfer mold 150.

The hard coat layer forming step S110 is not limited to the above, and may be performed by any known method. For example, the transfer of the shape by using a rigid roller to which a desired shape is imparted, the injection molding by using a stamper to which a desired shape is imparted, and the like may be performed.

[ step S120 of Forming an adhesion layer ]

Returning to fig. 5, the adhesion layer forming step S120 is a step of forming the adhesion layer 13 on the surface of the hard coat layer 12.

[ antireflection layer Forming Process S130]

The antireflection layer forming step S130 is a step of forming the antireflection layer 14 on the surface of the sealing layer 13. For example, the antireflection layer forming step S130 alternately forms the high refractive index layer 14a and the low refractive index layer 14b.

In the present embodiment, the adhesion layer forming step S120 and the antireflection layer forming step S130 are performed by a sputtering method. In this embodiment, from the viewpoint of increasing the film formation rate, a magnetron sputtering method is preferably used as the sputtering method. The sputtering method is not limited to the magnetron sputtering method, and a diode sputtering method using plasma generated by dc glow discharge or high frequency, a three-pole sputtering method with a heated cathode, or the like may be used.

[ antifouling layer Forming Process S140]

The antifouling layer forming step S140 is a step of forming an antifouling layer 15 on the surface of the antireflection layer 14. In the present embodiment, the antifouling layer forming step S140 is performed by, for example, a vacuum vapor deposition method.

By the above manufacturing method, the optical laminate 10 including the transparent substrate 11, the hard coat layer 12, the adhesion layer 13, the antireflection layer 14, and the stain-proofing layer 15 is obtained.

In the optical laminate 10 of the present embodiment, various layers may be provided on the second surface opposite to the first surface on which the hard coat layer 12 and the like are laminated, of the two surfaces of the transparent base material 11, as required. For example, an adhesive layer for bonding with other members may be provided. In addition, another optical film may be provided via the pressure-sensitive adhesive layer. Examples of the other optical film include: polarizing films (polarizing plates), retardation compensation films, films functioning as 1/2 wavelength plates and 1/4 wavelength plates, and the like.

Further, a layer having functions of antireflection, selective reflection, antiglare, polarization, phase difference compensation, viewing angle compensation or magnification, light guide, diffusion, luminance improvement, hue adjustment, conduction, or the like may be directly formed on the second surface of the transparent substrate 11.

The optical laminate 10 of the present embodiment can be applied to an optical member such as a polarizing plate or an image display device. For example, the optical layered body 10 may be provided on a display screen of an image display device such as a liquid crystal display panel or an organic EL display panel. Thus, for example, a high scratch resistance can be imparted to a touch panel display portion of a smart phone or an operating device, and an image display device having excellent durability and suitable for practical use can be realized.

The article to which the optical layered body 10 is applied is not limited to the example of the image display device described above. For example, the optical laminate 10 can be applied to various articles such as window glass, goggles, a light receiving surface of a solar cell, a screen of a smart phone, a display of a personal computer, an information input terminal, a tablet terminal, an AR (Augmented Reality: augmented Reality) device, a VR (Virtual Reality) device, an electro-optical display panel, a glass table surface, a game machine, an aircraft, a running support device for an electric car, a navigation system, a dashboard, and a surface of an optical sensor.

Examples

Hereinafter, examples and comparative examples of the present invention will be specifically described. The following examples are merely illustrative, and the optical laminate and the method for producing the optical laminate according to the present invention are not limited to the following examples.

Samples a to E and K were prepared as comparative examples, and samples F to J were prepared as examples as samples of the optical laminate. In addition, in producing samples a to J, resin a and resin B were prepared. The composition of resin A is shown in Table 1 below. The composition of resin B is shown in table 2 below. The unit of the blending ratio in tables 1 and 2 is wt%.

TABLE 1

TABLE 2

[ sample A: comparative example ]

As the transparent substrate 11, a TAC film (ZRD 60SL manufactured by fuji film) was used. Then, the resin a is contained by spin coating: 7.3 wt.%, butyl acetate: 91.2 wt% of a leveling agent BYK-377: 0.75% by weight of a water-forming organic filler SSX-101: 0.75% by weight of the mixed resin was coated on the transparent substrate 11. Spin coating conditions were set at 3500rpm. Then, the transparent substrate 11 coated with the mixed resin was dried at 80 ℃ for 1 minute, and then UV irradiation was performed to cure the mixed resin, thereby forming a hard coat layer on the transparent substrate 11. Then, after a metal oxide layer was formed on the hard coat layer using a sputtering apparatus, an antifouling layer was formed using a vapor deposition machine, and sample a was obtained.

It was confirmed that in sample a of the comparative example, a plurality of protrusion-like structures having different heights were dispersed. Further, in sample a of the comparative example, the concave portion was formed much more than the convex portion.

[ sample B: comparative example ]

Let resin a:9.8 wt.%, butyl acetate: 88 wt.% of leveling agent BYK-377: 1.2% by weight of a water-forming organic filler BMSA-18GN: sample B was obtained in the same manner as sample a except for 1.0 wt%.

In sample B of comparative example, it was confirmed that a plurality of protruding structures having different heights were dispersed in a floating island shape. Further, the concave portion of sample B of the comparative example was formed much more than the convex portion.

[ sample C: comparative example ]

Let resin a:11.1 wt%, butyl acetate: 86.5 wt.% of leveling agent BYK-377: 1.3% by weight of a water-forming organic filler BMSA-18GN: sample C was obtained in the same manner as sample A except for 1.1 wt%.

In sample C of the comparative example, a plurality of protruding structures having different heights were dispersed in a floating island shape. Further, the convex portion and the concave portion of the sample C of the comparative example are formed to be substantially equal.

[ sample D: comparative example ]

Sample D was obtained in the same manner as sample A except that the transparent substrate 11 and the hard coat layer were each a commercially available film A comprising a cured product of an acrylic resin composition containing filler particles having a particle diameter of 2 μm as a center on a TAC substrate having a thickness of 60. Mu.m.

In sample D of comparative example, a plurality of protruding structures having different heights were dispersed.

[ sample E: comparative example ]

Sample E was obtained in the same manner as sample A except that the transparent substrate 11 and the hard coat layer were each a commercially available film B comprising a cured product of an acrylic resin composition containing filler particles having a particle diameter of 5 μm as a center on a TAC substrate having a thickness of 60. Mu.m.

In sample E of the comparative example, a plurality of protruding structures having different heights were dispersed.

[ sample F: examples ]

As the transparent substrate 11, a TAC film (ZRD 60SL manufactured by fuji film) was used. The resin B was applied to the transparent substrate 11 so that the film thickness became 10 μm by a known method. Then, after the transparent substrate 11 coated with the resin B was dried at 80 ℃ for 1 minute, the sample a was laminated as the transfer mold 150. After the resin B is cured by UV irradiation, the sample a is peeled off from the transfer mold 150, and the hard coat layer 12 is formed on the transparent substrate 11. Next, after forming a metal oxide layer (the adhesion layer 13 and the antireflection layer 14) on the hard coat layer 12 using a sputtering apparatus, an antifouling layer 15 was formed using a vapor deposition machine, and a sample F was obtained.

It was confirmed that in the sample F of the example, the plurality of convex portions 62 having substantially the same height as each other were formed in a floating island shape. Further, it was confirmed that in the sample F, the top portions 62a of the convex portions 62 each have a substantially flat face. Moreover, the convex portion 62 of the sample F of the embodiment is formed much more than the concave portion 64.

[ sample G ]

Sample G was obtained in the same manner as sample F except that the transfer mold 150 to be laminated was set to sample B.

In sample G of the example, it was confirmed that the plurality of convex portions 62 having substantially the same height as each other were formed in a floating island shape. Further, it was confirmed that in the sample G, the top portions 62a of the convex portions 62 each have a substantially flat face. Moreover, the convex portion 62 of the sample G of the embodiment is formed much more than the concave portion 64.

[ sample H ]

Sample H was obtained in the same manner as sample F except that the transfer mold 150 to be laminated was set to sample C.

In sample H of the example, it was confirmed that the plurality of convex portions 62 having substantially the same height as each other were formed in a floating island shape. Further, it was confirmed that in the sample H, the top portions 62a of the convex portions 62 each have a substantially flat face. Further, the convex portion 62 and the concave portion 64 of the sample H of the embodiment are formed to be substantially equal.

[ sample I ]

Sample I was obtained in the same manner as sample F except that the transfer mold 150 to be laminated was set to sample D.

In sample I of the example, it was confirmed that the plurality of convex portions 62 having substantially the same height as each other were formed in a floating island shape.

[ sample J ]

Sample J was obtained in the same manner as sample F except that the transfer mold 150 to be laminated was set to sample E.

In sample J of the example, it was confirmed that the plurality of convex portions 62 having substantially the same height as each other were formed in a floating island shape.

[ sample K: comparative example ]

As the transparent substrate 11, a TAC film (ZRD 60SL manufactured by fuji film) was used. The resin B was applied to the transparent substrate 11 so that the film thickness became 10 μm by a known method. Then, after the transparent substrate 11 coated with the resin B was dried at 80 ℃ for 1 minute, the sample J was laminated as the transfer mold 150. After the resin B is cured by UV irradiation, the sample J is peeled off from the transfer mold 150, and a hard coat layer is formed on the transparent substrate 11. Next, after a metal oxide layer was formed on the hard coat layer using a sputtering apparatus, an antifouling layer was formed using a vapor deposition machine, and sample K was obtained.

In sample K of the comparative example, a plurality of protruding structures having different heights were dispersed.

[ evaluation of shape ]

The surface shapes of samples a to K were photographed using a scanning white interference microscope VS1800 manufactured by hitachi high technology corporation. The objective lens at the time of photographing was set to 20 times. After photographing, a csv file in which measurement data of the height of each pixel of the photographed image is recorded is obtained. Then, the lowest point of the height is detected from the csv file, and then an offset is applied to all data so that the lowest point becomes 0 (zero). Then, the highest point of the height is detected, and a histogram is created. Then, based on the histogram, the values of the height a and the mode P of the highest point shown in the above formula (1) are obtained.

Fig. 8 is a graph showing a histogram of sample a of the comparative example. Fig. 9 is a diagram showing a histogram of sample B of the comparative example. Fig. 10 is a graph showing a histogram of sample C of the comparative example. Fig. 11 is a diagram showing a histogram of sample D of the comparative example. Fig. 12 is a graph showing a histogram of sample E of the comparative example. Fig. 13 is a graph showing a histogram of sample K of the comparative example. In fig. 8 to 13, the broken line indicates the value of "a/1.9".

As shown in FIG. 8, the highest point of sample A of comparative example had a height A of 3.41 μm and mode P of 1.76. Thus, sample A became A/1.9> P. That is, in the histogram shown in fig. 8, the mode P is located on the left side of the broken line representing a/1.9.

As shown in FIG. 9, the highest point of sample B of comparative example had a height A of 2.21 μm and mode P of 0.43. Thus, sample B became A/1.9> P. That is, in the histogram shown in fig. 9, the mode P is located on the left side of the broken line representing a/1.9.

As shown in FIG. 10, the highest point of sample C of comparative example had a height A of 1.71 μm and mode P of 0.30. Thus, sample C became A/1.9> P. That is, in the histogram shown in fig. 10, the mode P is located on the left side of the broken line representing a/1.9.

As shown in FIG. 11, the highest point of sample D of comparative example had a height A of 1.29 μm and mode P of 0.30. Thus, sample D became A/1.9> P. That is, in the histogram shown in fig. 11, the mode P is located on the left side of the broken line representing a/1.9.

As shown in FIG. 12, the highest point of sample E of comparative example had a height A of 2.51 μm and mode P of 0.49. Thus, sample E became A/1.9> P. That is, in the histogram shown in fig. 12, the mode P is located on the left side of the broken line representing a/1.9.

As shown in FIG. 13, the highest point of sample K of the comparative example had a height A of 1.90 μm and mode P of 0.59. Thus, sample K became A/1.9> P. That is, in the histogram shown in fig. 13, the mode P is located on the left side of the broken line representing a/1.9.

Fig. 14 is a graph showing a histogram of sample F of the example. Fig. 15 is a graph showing a histogram of sample G of the example. Fig. 16 is a diagram showing a histogram of sample H of the example. Fig. 17 is a graph showing a histogram of sample I of the example. Fig. 18 is a graph showing a histogram of sample J of the example. In fig. 14 to 18, the broken line indicates the value of "a/1.9".

As shown in FIG. 14, the highest point of sample F of the example was 3.26 μm in height A and 2.62 in mode P. Thus, sample F became A/1.9< P. That is, in the histogram shown in fig. 14, the mode P is located on the right side of the broken line representing a/1.9.

As shown in FIG. 15, the highest point of sample G of the example was 2.66 μm in height A and 2.21 in mode P. Thus, sample G became A/1.9< P. That is, in the histogram shown in fig. 15, the mode P is located on the right side of the broken line representing a/1.9.

As shown in FIG. 16, the highest point of sample H of the example had a height A of 1.67 μm and mode P of 1.17. Thus, sample H became A/1.9< P. That is, in the histogram shown in fig. 16, the mode P is located on the right side of the broken line representing a/1.9.

As shown in FIG. 17, the highest point of sample I of the example had a height A of 1.22 μm and mode P of 0.87. Thus, sample I became A/1.9< P. That is, in the histogram shown in fig. 17, the mode P is located on the right side of the broken line representing a/1.9.

As shown in fig. 18, the highest point of sample J of the example has a height a of 2.57 μm and a mode P of 2.08. Thus, sample J becomes A/1.9< P. That is, in the histogram shown in fig. 18, the mode P is located on the right side of the broken line representing a/1.9.

From the above results, it was confirmed that samples F, G, H, I, and J of the examples satisfy the above formula (1). That is, it was confirmed that, in samples F to J of the examples, the top portions 62a of the plurality of convex portions 62 had substantially the same height as each other in the concave-convex surface 60 of the outermost surface (surface of the stain-proofing layer 15) of the optical laminate 10, and the top portions 62a of the plurality of convex portions 62 each had a substantially flat surface, and the concave-convex surface 60 had a rough surface structure excellent in scratch resistance.

On the other hand, it was confirmed that samples a, B, C, D, E, and K of the comparative examples did not satisfy the above formula (1). That is, it was confirmed that the heights of the top portions of the plurality of convex portions were not substantially the same in the concave-convex surfaces of the outermost surfaces (surfaces of the stain-proofing layers) of the optical layered body in samples a to E and K of the comparative example, and that the concave-convex surfaces had a protrusion-like structure including a large number of sharp protrusions (tips) having different heights, and the scratch resistance was poor.

[ evaluation of scratch resistance ]

Transparent PSA made using paper from bacon: (TD 06A) test pieces were produced by bonding samples A to E and K of comparative examples and samples F to J of examples to 100mm×50mm green sheet glass, respectively. Next, using a friction tester type I according to JIS L0849, the friction body was horizontally reciprocated along the surface of each test piece. As the friction body, steel wool (model #0000 manufactured by Bonstar corporation) was used. The conditions for the friction test were set to a load of 1kg, a contact area of 1 cm. Times.1 cm, a sliding distance of 50mm, and a sliding speed of 60 reciprocations/min. Further, the number of horizontal reciprocations was set to 2000. Then, the contact angle of pure water was measured.

The contact angle (WCA) for pure water was measured by an ellipsometry using a full-automatic contact angle meter DM-700 (manufactured by Kagaku Kogyo Co., ltd.) under the following conditions. Distilled water was introduced into a glass syringe, and a stainless steel needle was attached to the tip of the syringe, and pure water was added dropwise to each test piece.

The dropping amount of pure water: 2.0. Mu.L.

Measuring temperature: 25 ℃.

The contact angle after dropping pure water and passing 4 seconds was measured at any six places on the surface of the test piece, and the average value thereof was taken as the pure Water Contact Angle (WCA).

[ optical evaluation ]

External haze values of samples a to E and K of the comparative examples and samples F to J of the examples were measured. The external haze value was measured using NDH-7000, manufactured by Nippon Denshoku Co., ltd., based on JIS K7136.

The results of the measurements in samples F to J of the above examples are summarized in Table 3 below. The results of measurement in samples a to E and sample K of the comparative examples are summarized in table 4 below.

TABLE 3

TABLE 4

Referring to the results of tables 3 and 4, it is understood that the external haze values [% ] of samples F to J of examples are 3% to 40% as in samples a to E and K of comparative examples. Therefore, it was confirmed that samples F to J of examples had external haze values [% ] to the same extent as samples a to E and sample K of comparative examples.

When the results of tables 3 and 4 are referred to, it is found that the surface roughness Sa [ nm ] of samples F to J of examples is 60nm to 250nm as in samples A to E and K of comparative examples. Therefore, it was confirmed that samples F to J of examples had the same degree of surface roughness Sa as samples a to E and sample K of comparative examples.

From the above measurement results of the external haze value [% ] and the surface roughness Sa [ nm ], it is understood that samples F to J of examples have the same degree of antiglare property as samples A to E and sample K of comparative examples.

Further, when the results of table 3 were referred to, it was confirmed that samples F to J of examples satisfied the above formula (1). That is, in samples F to J of the examples, it was confirmed that the top portions 62a of the plurality of convex portions 62 constituting the concave-convex surface 60 of the outermost surface (the stain-proofing layer 15) had substantially the same height as each other, and that the top portions 62a of the plurality of convex portions 62 each had a substantially flat surface.

On the other hand, when the results of table 4 were referred to, it was confirmed that samples a to E and sample K of the comparative example did not satisfy the above formula (1). That is, it was confirmed that in samples a to E and sample K of the comparative examples, the heights of the top portions of the plurality of convex portions constituting the concave-convex surface of the outermost surface (antifouling layer) were not substantially the same, and the top portions were not flat surfaces, that is, had a protrusion-like structure having a plurality of protrusions having different heights.

Further, when the results of table 3 were referred to, it was confirmed that the contact angle of the outermost surface after the friction test was performed on samples F to J of examples to water was 90 degrees or more. Thus, it was found that samples F to J of examples have high scratch resistance.

On the other hand, when the results of table 4 were referred to, it was confirmed that the contact angle of the outermost surface of the comparative examples, samples a to E and sample K, after the friction test, was 58 degrees or less with respect to water.

That is, the contact angle of the outermost surface after the friction test was performed on samples F to J of examples to water was 1.57 to 1.96 times that of samples a to E and sample K of comparative examples.

As described above, according to the present embodiment, it is possible to provide an optical laminate 10, and a polarizing plate and an image display device including the optical laminate 10, in which the optical laminate 10 has the same degree of antiglare properties as in the conventional technique in which a concave-convex structure is formed by filler particles of about 1 μm or more and 10 μm or less, and the scratch resistance is greatly improved as compared with the conventional technique.

The embodiments of the present invention have been described above with reference to the drawings, but it is needless to say that the present invention is not limited to the embodiments. It is obvious that various changes and modifications will occur to those skilled in the art within the scope of the present invention as defined in the appended claims, and it is to be understood that these are also within the technical scope of the present invention.

In the above embodiment, the case where the optical laminate 10 includes the adhesion layer 13, the antireflection layer 14, and the stain-proofing layer 15 is exemplified. However, the optical laminate 10 may be provided with at least one or more metal oxide layers made of metal oxide on the hard coat layer 12. The metal oxide layer may be various optical functional layers described above. For example, the optical laminate 10 may include a transparent substrate 11, a hard coat layer 12, an adhesive layer 13, an optical functional layer, and an antifouling layer 15. Further, either one or both of the sealing layer 13 and the stain-proofing layer 15 may not be provided.

Description of the reference numerals

10: an optical laminate; 11: a transparent substrate; 12: a hard coat layer; 13: an adhesion layer (metal oxide layer); 14: an antireflection layer (metal oxide layer); 14a: a high refractive index layer; 14b: a low refractive index layer; 150: transferring a mold; 30: a concave-convex structure; 32: a convex portion; 32a: a top; 34: a concave portion; 60: a concave-convex surface; 62: a convex portion; 62a: a top; 64: a recess.

Claims

1. An optical laminate comprising:

a transparent substrate;

at least one hard coat layer provided on the transparent substrate and formed of a resin composition; and

at least one metal oxide layer provided on the hard coat layer and composed of a metal oxide,

a concave-convex structure is formed on the surface of the hard coat layer on the metal oxide layer side,

the height distribution of the surface of the concave-convex structure satisfies the following formula (1),

A/1.9<P……(1)

a: setting the height B of the lowest point of the surface of the concave-convex structure to 0,

2. The optical stack according to claim 1, wherein,

The tops of the plurality of convex portions of the concave-convex structure constituting the hard coat layer have substantially the same height as each other.

3. The optical stack according to claim 2, wherein,

the outermost surface of the optical laminate is a concave-convex surface following the shape of the concave-convex structure of the hard coat layer,

the tops of the plurality of convex portions constituting the concave-convex surface have substantially the same height as each other.

4. The optical laminate according to any one of claim 1 to 3, wherein,

the tops of the plurality of convex portions constituting the concave-convex structure of the hard coat layer each have a substantially flat surface.

5. The optical stack according to claim 4, wherein,

the tops of the plurality of projections constituting the concave-convex surface each have a substantially flat surface.

6. The optical laminate according to any one of claim 1 to 3, wherein,

the surface roughness Sa of the concave-convex structure of the hard coat layer is 50nm or more and 300nm or less.

7. The optical laminate according to any one of claim 1 to 3, wherein,

Using a friction tester using steel wool, loading the steel wool with: 1kg, contact area: 1 cm. Times.1 cm, reciprocating: the contact angle of the outermost surface of the optical laminate after rubbing the surface of the optical laminate 2000 times to water is 90 degrees or more.

8. The optical laminate according to any one of claim 1 to 3, wherein,

the external haze value defined in JIS K7136 is 3% or more and 40% or less.

9. The optical laminate according to any one of claim 1 to 3, wherein,

the hard coat layer contains metal oxide fine particles having an average particle diameter of 20nm or more and 100nm or less.

10. The optical laminate according to any one of claim 1 to 3, wherein,

the hard coat layer does not contain filler particles having an average particle diameter of 1 μm or more.

11. The optical laminate according to any one of claim 1 to 3, wherein,

the metal oxide layer comprises an anti-reflective layer,

the antireflection layer is constituted by a laminate in which low refractive index layers and high refractive index layers having a refractive index larger than that of the low refractive index layers are alternately laminated,

the optical laminate is an antireflection film having an antiglare function and an antireflection function.

12. The optical stack according to claim 11, wherein,

the metal oxide layer comprises a sealing layer arranged between the hard coating layer and the anti-reflection layer.

13. A polarizing plate comprising the optical laminate according to any one of claims 1 to 3.

14. An image display device provided with the optical laminate according to any one of claims 1 to 3.

15. A method for producing the optical laminate according to any one of claims 1 to 3, comprising:

a step of providing a hard coat layer formed of a resin composition on a transparent substrate;

a step of providing at least one metal oxide layer on the hard coat layer; and

a step of providing an antifouling layer on the metal oxide layer,

the step of providing the hard coat layer includes:

a step of applying the resin composition to the surface of the transparent substrate; and

and transferring the concave-convex shape of the transfer mold to the resin composition.