WO2023224104A1

WO2023224104A1 - Optical laminate and image display device using same

Info

Publication number: WO2023224104A1
Application number: PCT/JP2023/018649
Authority: WO
Inventors: 怜士金田; 拓也木▲崎▼; 匠齋藤
Original assignee: 凸版印刷株式会社
Priority date: 2022-05-20
Filing date: 2023-05-18
Publication date: 2023-11-23

Abstract

Provided is an optical laminate having excellent optical characteristics and fingerprint wipeability, and an image display device that uses the optical laminate. Provided is an optical laminate having recesses and protrusions in the outermost surface shape thereof, the optical laminate being characterized by satisfying conditions (1) through (3) simultaneously.　(1): 40,000 ≤ A ≤ 300,000. (2): 300 ≤ B ≤ 1,000. (3): 30 ≤ C ≤ 500. Here, when a spatial frequency f is calculated by performing frequency analysis by fast Fourier transform of an image based on three-dimensional data of the recess/protrusion height of the recessed/protruding shape measured by an optical interference method or a contact method, A is the average value of the power spectrum intensity in a range of 0 < f ≤ 100 cycles/mm, B is the average value of the power spectrum intensity in a range of 100 cycles/mm < f ≤ 200 cycles/mm, and C is the average value of the power spectrum intensity in a range of 200 cycles/mm < f ≤ 300 cycles/mm.

Description

Optical laminate and image display device using the same

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

The AG (anti-glare) film is equipped with an anti-glare layer having fine irregularities on its surface, and the fine irregularities diffuse reflected light, thereby suppressing the reflection of external light. Furthermore, an AGLR film is known in which a low refractive index layer (LR) is laminated on an anti-glare layer and further uses optical interference to suppress reflected light, and is used in various displays.

The anti-glare properties of AG films and AGLR films are mainly determined by the uneven shape of the surface of the anti-glare layer. Conventionally, a suitable uneven shape on the surface of an anti-glare layer has often been expressed using a surface roughness parameter defined in ISO 25178 or a line roughness parameter defined in JIS B 0601 (for example, Patent Document (See 1 to 3).

Furthermore, AG films and AGLR films for use in displays with touch panels are required to have good anti-glare properties as well as ease of wiping away fingerprints and the like that adhere to the film during operation.

Patent No. 5360616 Patent No. 5382034 Patent No. 6135131

The fingerprint wiping properties required for optical laminates for use in displays with touch panels vary depending on the shape of the irregularities on the outermost surface. Therefore, as a method for expressing the fingerprint wiping property of an optical laminate, it is possible to employ the above-mentioned roughness parameter and design an optical laminate having good fingerprint wiping property based on the roughness parameter.

However, the conventional roughness parameters described above cannot represent all random uneven shapes and complex uneven shapes. For example, the arithmetic mean height Sa specified in ISO 25178 is an index commonly used when evaluating surface roughness, but even if the Sa value is the same, the uneven shape and fingerprint wiping performance are It may vary greatly. Therefore, conventional roughness parameters are not suitable for expressing fingerprint wiping properties.

An object of the present invention is to provide an optical laminate with excellent optical properties and fingerprint wiping properties, and an image display device using the same.

The optical laminate according to the present invention is characterized in that it has an uneven shape on its outermost surface and satisfies the following conditions (1) to (3) at the same time.
40,000≦A≦300,000 (1)
300≦B≦1,000 (2)
30≦C≦500 (3)
Here, the three-dimensional data of the height of the unevenness measured by the optical interference method or the contact method is converted into first image data whose pixel value is the height of the unevenness, and the first image data is subjected to fast Fourier transformation. Convert it to a second image by , and calculate the spatial frequency f of the X coordinate of the power spectrum of the image that passes through the origin and within a range of ±20 pixels on the positive X axis and Y axis direction. In the case that
A: average value of power spectrum intensity in the range of 0<f≦100cycle/mm,
B: average value of power spectrum intensity in the range of 100cycle/mm<f≦200cycle/mm,
C: Average value of power spectrum intensity in the range of 200 cycles/mm<f≦300 cycles/mm.

An image display device according to the present invention includes the optical laminate described above.

According to the present invention, it is possible to provide an optical laminate with excellent optical properties, appearance, and fingerprint wiping properties, and an image display device using the same.

FIG. 1 is a cross-sectional view schematically showing an example of an optical laminate according to an embodiment. FIG. 2 is a cross-sectional view schematically showing another example of the optical laminate according to the embodiment. FIG. 3 is a diagram showing a method for evaluating anti-glare properties. FIG. 4 is a diagram showing an example of evaluation of anti-glare properties.

FIG. 1 is a cross-sectional view schematically showing an example of an optical laminate according to an embodiment.

The optical laminate 11 includes a transparent support 2 and an anti-glare layer 3 (AG layer) laminated on one side of the transparent support 2. The optical laminate 11 is an optical film that suppresses reflection of external light by scattering incident light with fine irregularities on the outermost surface (also referred to as "AG film").

The transparent support 2 is a film that serves as the base of the optical laminate 11, and is made of a material that has excellent visible light transmittance. Materials for forming the transparent support 2 include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyacrylates such as polymethyl methacrylate, polyamides such as nylon 6 and nylon 66, polyimides, Transparent resins such as polyarylate, polycarbonate, triacetyl cellulose, polyacrylate, polyvinyl alcohol, polyvinyl chloride, cycloolefin copolymer, norbornene-containing resin, polyether sulfone, polysulfone, and inorganic glass can be used. The thickness of the transparent support 2 is not particularly limited, but is preferably 10 to 200 μm. Furthermore, when a low water vapor permeability is required, it is preferable to use a film made of a material with a low water vapor permeability such as polyethylene terephthalate, cycloolefin polymer, polypropylene, or the like.

The surface of the transparent support 2 may be subjected to surface modification treatment in order to improve adhesion to other layers to be laminated. Examples of the surface modification treatment include alkali treatment, corona treatment, plasma treatment, sputtering treatment, application of a surfactant or silane coupling agent, Si vapor deposition, and the like.

The anti-glare layer 3 is a functional layer that forms fine irregularities on the outermost surface of the optical laminate 11.

The anti-glare layer 3 is formed by applying a coating solution containing an active energy ray-curable compound and organic fine particles and/or inorganic fine particles (filler) to the transparent support 2 and curing the coating film. .

As the active energy ray-curable compound, for example, a monofunctional, bifunctional, or trifunctional or more functional (meth)acrylate monomer can be used. In this specification, "(meth)acrylate" is a generic term for both acrylate and methacrylate, and "(meth)acryloyl" is a generic term for both acryloyl and methacryloyl.

Examples of monofunctional (meth)acrylate compounds include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, n-butyl (meth)acrylate, and isobutyl (meth)acrylate. meth)acrylate, t-butyl(meth)acrylate, glycidyl(meth)acrylate, acryloylmorpholine, N-vinylpyrrolidone, tetrahydrofurfuryl acrylate, cyclohexyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, isobornyl(meth)acrylate, ) acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, benzyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 3- Methoxybutyl (meth)acrylate, ethyl carbitol (meth)acrylate, phosphoric acid (meth)acrylate, ethylene oxide modified phosphoric acid (meth)acrylate, phenoxy (meth)acrylate, ethylene oxide modified phenoxy (meth)acrylate, propylene oxide modified Phenoxy (meth)acrylate, nonylphenol (meth)acrylate, ethylene oxide-modified nonylphenol (meth)acrylate, propylene oxide-modified nonylphenol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypropylene glycol ( meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-phenoxypropyl(meth)acrylate, 2-(meth)acryloyloxyethyl hydrogen phthalate, 2-(meth)acryloyloxy Propyl hydrogen phthalate, 2-(meth)acryloyloxypropyl hexahydrohydrogen phthalate, 2-(meth)acryloyloxypropyl tetrahydrohydrogen phthalate, dimethylaminoethyl (meth)acrylate, trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth) ) acrylate, hexafluoropropyl (meth)acrylate, octafluoropropyl (meth)acrylate, 2-adamantane, adamantane derivative mono(meth)acrylate such as adamantyl acrylate having a monovalent mono(meth)acrylate derived from adamantane diol etc.

Examples of difunctional (meth)acrylates include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, and nonanediol di(meth)acrylate. , ethoxylated hexanediol di(meth)acrylate, propoxylated hexanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, ) acrylate, neopentyl glycol di(meth)acrylate, ethoxylated neopentyl glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, di(meth)acrylate such as neopentyl glycol hydroxypivalate di(meth)acrylate Examples include acrylate.

Examples of trifunctional or higher functional (meth)acrylates include trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, and tris-2-hydroxyethyl isocyanate. Trifunctional tri(meth)acrylates such as nurate tri(meth)acrylate, glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, and ditrimethylolpropane tri(meth)acrylate (meth)acrylate compounds, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, ditrimethylolpropane penta(meth)acrylate Acrylate, dipentaerythritol hexa(meth)acrylate, ditrimethylolpropane hexa(meth)acrylate, and other polyfunctional (meth)acrylate compounds with three or more functionalities, or some of these (meth)acrylates with an alkyl group or ε-caprolactone. Examples include substituted polyfunctional (meth)acrylate compounds.

Additionally, urethane (meth)acrylate can also be used as a polyfunctional monomer. Examples of urethane (meth)acrylate include those obtained by reacting a (meth)acrylate monomer having a hydroxyl group with a product obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer. .

Examples of urethane (meth)acrylates include pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, dipentaerythritol pentaacrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate toluene diisocyanate urethane prepolymer, dipentaerythritol pentaacrylate toluene diisocyanate Examples include urethane prepolymer, pentaerythritol triacrylate isophorone diisocyanate urethane prepolymer, dipentaerythritol pentaacrylate isophorone diisocyanate urethane prepolymer.

The above-mentioned polyfunctional monomers may be used alone or in combination of two or more. Further, the above-mentioned polyfunctional monomer may be a monomer in the coating liquid, or may be a partially polymerized oligomer.

The organic fine particles are a material that mainly forms fine irregularities on the surface of the anti-glare layer 3 and provides a function of diffusing external light. Organic fine particles are made of translucent resin materials such as acrylic resin, polystyrene resin, styrene-(meth)acrylate copolymer, polyethylene resin, epoxy resin, silicone resin, polyvinylidene fluoride, and polyethylene fluoride resin. Resin particles can be used. In order to adjust the refractive index and the dispersion of the resin particles, two or more types of resin particles having different materials (refractive indexes) may be mixed and used.

The inorganic fine particles added to the composition for forming an anti-glare layer are preferably nanoparticles with an average particle size of 10 to 200 nm.

The inorganic fine particles are a material mainly for adjusting sedimentation and aggregation of the organic fine particles in the anti-glare layer 3. As the inorganic fine particles, silica fine particles, metal oxide fine particles, various mineral fine particles, etc. can be used. As the silica fine particles, for example, colloidal silica, silica fine particles surface-modified with a reactive functional group such as a (meth)acryloyl group, etc. can be used. As the metal oxide fine particles, for example, alumina, zinc oxide, tin oxide, antimony oxide, indium oxide, titania, zirconia, etc. can be used. Examples of mineral fine particles include mica, synthetic mica, vermiculite, montmorillonite, iron-montmorillonite, bentonite, beidellite, saponite, hectorite, stevensite, nontronite, magadiite, islarite, kanemite, layered titanate, smectite, and synthetic. Smectite etc. can be used. The mineral fine particles may be either natural products or synthetic products (including substituted products and derivatives), and a mixture of both may be used. Among the mineral fine particles, layered organic clay is more preferable. Layered organic clay refers to a swellable clay in which organic onium ions are introduced between the layers. The organic onium ion is not limited as long as it can be organicized using the cation exchange properties of the swelling clay. When using a layered organic clay mineral as the mineral fine particles, the above-mentioned synthetic smectite can be suitably used. Synthetic smectite has the function of increasing the viscosity of the composition for forming an anti-glare layer, suppressing sedimentation of resin particles and inorganic fine particles, and adjusting the uneven shape of the surface of the optical functional layer.

A polymerization initiator may be added to cure the composition for forming an anti-glare layer by irradiating ultraviolet rays. As the polymerization initiator, a polymerization initiator that generates radicals upon irradiation with ultraviolet light can be used. As the polymerization initiator, radical polymerization initiators such as acetophenone, benzophenone, thioxanthone, benzoin, benzoin methyl ether, and acylphosphine oxide can be used. As a polymerization initiator, for example, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,2-diethoxyacetophenone, 1-hydroxycyclohexylphenyl ketone , 2,2-dimethoxy-phenylacetophenone, dibenzoyl, benzoin, benzoin methyl ether, benzoin ethyl ether, p-chlorobenzophenone, p-methoxybenzophenone, Michler's ketone, acetophenone, 2-chlorothioxanthone, and the like. One type of these may be used alone, or two or more types may be used in combination.

Furthermore, it is preferable to add an antifouling agent, a leveling agent, an oil repellent, a water repellent, and an anti-fingerprint agent to the composition for forming an anti-glare layer as components for improving antifouling properties. As these additives, fluorine-containing compounds and silicone compounds can be suitably used. By adding an antifouling compound to the antiglare layer 3, which is the outermost layer, fingerprint wiping properties can be further improved. Other additives include antistatic agents, antifoaming agents, antioxidants, ultraviolet absorbers, infrared absorbers, colorants, light stabilizers, polymerization inhibitors, photosensitizers, antibacterial agents, antiviral agents, etc. may be added as necessary.

Furthermore, a solvent may be added to the composition for forming an anti-glare layer, if necessary. Examples of solvents include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, butanol, isopropyl alcohol, and isobutanol, ketones such as acetone, methyl ethyl ketone, cyclohexanone, and methyl isobutyl ketone, and ketone alcohols such as diacetone alcohol. , aromatic hydrocarbons such as benzene, toluene, xylene, glycols such as ethylene glycol, propylene glycol, hexylene glycol, ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, diethyl cellosolve, diethyl carbitol, propylene glycol Glycol ethers such as monomethyl ether, esters such as methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, amyl acetate, ethers such as dimethyl ether and diethyl ether, N-methylpyrrolidone, dimethylformamide, etc. , one type or a mixture of two or more types can be used.

FIG. 2 is a cross-sectional view schematically showing another example of the optical film according to the embodiment.

The optical laminate 12 includes a transparent support 2, an anti-glare layer 3 laminated on one side of the transparent support 2, and a low refractive index layer 4 (AR layer) laminated on the surface of the anti-glare layer 3. . The optical laminate 12 is an optical film that suppresses reflection and reflection of external light by utilizing scattering of incident light and optical interference due to minute irregularities on the outermost surface (also referred to as "AGLR film"). .

The low refractive index layer 4 is a functional layer that has a refractive index lower than that of the anti-glare layer 3 below, and suppresses reflection by optical interference.

The low refractive index layer 4 can be formed by applying a composition containing an active energy ray-curable compound to the surface of the anti-glare layer 3 and curing the coating film. The low refractive index layer 4 may contain low refractive index fine particles to adjust the refractive index.

Examples of low refractive index fine particles include fine particles such as LiF, MgF, 3NaF・AlF, or AlF (all have a refractive index of 1.4), or Na ₃ AlF ₆ (cryolite, a refractive index of 1.33), Silica fine particles having voids inside can be preferably used. Silica fine particles having voids inside can have the refractive index of air (approximately 1) in the void portion, and are therefore free to lower the refractive index of the low refractive index layer 4. Specifically, porous silica particles and shell-structured silica particles can be used. Note that the low refractive index fine particles are not necessarily necessary, and if the refractive index of the active energy ray-curable compound after curing is lower than the refractive index of the anti-glare layer 3, the low refractive index fine particles may be omitted.

As the active energy ray-curable compound, the polymerizable compounds described in the anti-glare layer can be used. Further, the above-mentioned polymerization initiator and solvent may be appropriately added to the composition for forming a low refractive index layer.

Since the low refractive index layer 4 is a functional layer that is the outermost layer, the composition for forming the low refractive index layer contains an antifouling agent, a leveling agent, an oil repellent, and a water repellent as components for improving antifouling properties. It is preferable to add an anti-fingerprint agent. As these additives, fluorine-containing compounds and silicone compounds can be suitably used. Other additives include antistatic agents, antifoaming agents, antioxidants, ultraviolet absorbers, infrared absorbers, colorants, light stabilizers, polymerization inhibitors, photosensitizers, antibacterial agents, antiviral agents, etc. may be added as necessary.

The antibacterial agent and antiviral agent mentioned above may be a component that functions as either an antibacterial agent or an antiviral agent, or a component that functions as both an antibacterial agent and an antiviral agent, It may be a component whose function as an antibacterial agent or an antiviral agent changes depending on conditions such as the amount added.

The antibacterial agent and antiviral agent may be an inorganic material or an organic material. Further, the antibacterial agent and antiviral agent may or may not be particulate. When the antibacterial agent or antiviral agent is in particulate form, the average particle diameter is preferably 1 μm or less.

Functional components of inorganic materials that can be used as antibacterial agents and antiviral agents include, for example, metals such as silver, copper, and zinc, metal oxides such as zinc oxide, and metal hydroxides such as calcium hydroxide. The above-mentioned metal may be a metal particle, or may be in the form of an ion, a complex, or a salt. Further, the metal may be supported on a carrier. Examples of the carrier include zeolite, phosphate carriers such as zirconium phosphate, silica gel, activated carbon, and glass materials. Further, the functional component of the inorganic material may be a non-photocatalyst such as titania phosphate or a compound that functions as a photocatalyst such as titanium oxide. These compounds may be used in combination with the above metals. Among the above, as the functional component of the inorganic material, inorganic particles containing a metal or a metal oxide are preferably used, and in particular, a material containing silver is suitably used.

The functional component of the organic material that can be used as an antibacterial agent or antiviral agent may be a synthetic component or a natural component. Examples of synthetic components include quaternary ammonium salts, biguanide compounds such as polyhexamethylene biguanide, and triclosan. Examples of natural ingredients are hinokitiol, terpenes, etc.

A hard coat layer, a high refractive index layer, a medium refractive index layer, an antistatic layer, an electromagnetic wave blocking layer, an infrared absorbing layer, an ultraviolet absorbing layer, a color correction layer, etc. are provided between the transparent support 2 and the anti-glare layer 3. One or more functional layers may be stacked.

The coating method of the anti-glare layer forming composition and the low refractive index layer forming composition described above is not particularly limited, and examples thereof include a spin coater, a roll coater, a reverse roll coater, a gravure coater, a microgravure coater, a knife coater, Coating can be performed using a bar coater, wire bar coater, die coater, dip coater, spray coater, applicator, etc.

Here, details of the surface unevenness shape of the optical laminate according to this embodiment will be explained.

The uneven shape on the outermost surface of the optical functional laminate according to this embodiment satisfies the following conditions (1) to (3) at the same time.
40,000≦A≦300,000 (1)
300≦B≦1,000 (2)
30≦C≦500 (3)
Here, A, B, and C are images obtained by fast Fourier transform (hereinafter referred to as "FFT") of the image data generated from the measurement data of the height of unevenness on the surface of the optical laminate. This is a value derived from the spatial frequency f calculated from a predetermined range. A is the average value of the power spectrum intensity in the range of 0<f≦100cycle/mm, B is the average value of the power spectrum intensity in the range of 100cycle/mm<f≦200cycle/mm, and C is the average value of the power spectrum intensity in the range of 200cycle/mm. /mm<f≦300cycle/mm.

The method for calculating the values of A, B, and C above is as follows.

First, three-dimensional data of the height of the unevenness on the outermost surface of the optical laminate is obtained by measurement. The three-dimensional data of the height of the unevenness includes the position within the measurement plane and the height of the unevenness. The three-dimensional data of the height of the irregularities on the outermost surface can be measured by an optical interference method or a contact method. The acquired three-dimensional data is converted into an image (first image) whose pixel value is the height of the unevenness. Next, FFT is performed on the first image to obtain an image after FFT processing (second image). Next, the X coordinate of the power spectrum in a predetermined range in the second image after FFT processing is converted into a spatial frequency f. From the obtained spatial frequency, the average value of the antilog of the power spectrum intensity in the range of 0<f≦100cycle/mm, the range of 100cycle/mm<f≦200cycle/mm, and the range of 200cycle/mm<f≦300cycle/mm are calculated and set as the values of A, B, and C above.

Conventionally, in order to improve fingerprint wiping properties, it is common to include antifouling ingredients such as fluorine compounds and silicone compounds in the outermost layer, but adding antifouling ingredients alone does not improve fingerprint wiping properties. There was a limit. The inventors of the present invention have conducted studies and found that the fingerprint wiping property is affected not only by the material of the outermost surface and the components contained therein, but also by the shape of the surface irregularities. In addition, when the inventors of the present application investigated uneven shapes that can improve fingerprint wiping performance, it was found that the power spectrum intensity around a spatial frequency of 50 cycles/mm is greatly related to fingerprint wiping performance; It was found that the higher the power spectrum intensity (that is, the higher the unevenness height), the better the fingerprint wiping property was.

When the above conditions (1) to (3) are met, fingerprint wiping performance is improved due to the oil-repellent effect (lotus effect) due to the unique surface unevenness, and because the surface unevenness is physically easy to wipe off. This is thought to be due to a combination of factors such as the easy-to-use shape. If any value of A to C is out of the range of conditions (1) to (3), fingerprint wiping performance will deteriorate, or surface scattering will become stronger, resulting in higher haze or whitish appearance. etc., the optical properties deteriorate. In addition, mechanical properties such as scratch resistance may also deteriorate.

The optical laminates 11 and 12 according to the present embodiment have excellent fingerprint wiping properties because the uneven shape of the outermost surface satisfies the conditions (1) to (3) above. Further, by adding an antifouling component such as an antifouling agent to the functional layer serving as the outermost layer, the fingerprint wiping property can be further improved.

The optical laminates 11 and 12 according to this embodiment are used on the outermost surface of a device that can be touched with a finger. Due to the recent social situation regarding the new coronavirus, the optical laminates 11 and 12 are also required to have antibacterial and antiviral properties. Therefore, by adding an antibacterial agent and/or an antiviral agent to the antiglare layer 3 or the low refractive index layer 4, antibacterial and/or antiviral properties can be imparted. If an antibacterial agent and/or an antiviral agent is added to the outermost layer of the optical laminate, it is easy to obtain a higher antibacterial and/or antiviral effect; Even when an antibacterial and/or antiviral agent is added to layer 3, if the antibacterial component or antiviral component is eluted, the antibacterial and/or antiviral property will be exhibited.

The values of A to C are controlled by adjusting the particle size and amount of the filler added to the anti-glare layer 3, the amount of additive, the thickness of the anti-glare layer 3, and the agglomeration state of the filler in the film forming process. be able to.

The optical laminates 11 and 12 according to this embodiment can be used to configure an image display device by being laminated to the outermost surface of an image display panel such as a liquid crystal panel or an organic EL panel. A touch panel may be provided between the optical laminates 11 and 12 and the image display panel. The optical laminates 11 and 12 according to this embodiment have excellent fingerprint wiping properties and are therefore suitable as optical films provided on the outermost surface of an image display device.

Examples in which the present invention was specifically implemented will be described below.

(Example 1a)
The following hard coat (HC) compositions were prepared.

(HC composition 1: for forming anti-glare layer)
Using a paint shaker, organic fine particles (manufactured by Techpolymer, SSX-2035) with an average particle size of 3.5 μm were dispersed in toluene for 40 minutes, and then 5.0 parts by mass of organic fine particles, pentaerythritol expressed by the following formula, and 92.0 parts by mass of a condensate of acrylic acid (manufactured by Osaka Organic Chemical Industry Co., Ltd., Viscoat #300, hereinafter referred to as "PETA"), 3.0 parts by mass of a photopolymerization initiator (manufactured by IGM Resins B.V., Omnirad 184) 1 part toluene. The total solid content concentration in the composition was adjusted to 50% by mass. The mixture was stirred in a paint shaker for 40 minutes to obtain HC composition 1.

(HC composition 2: for forming a low refractive index layer)
45.0 parts by mass of PETA (Viscoat #300, manufactured by Osaka Organic Chemical Industry Co., Ltd.), 50.0 parts by mass of hollow silica particles dispersed in isopropyl alcohol with an average particle size of 75 nm, and a photopolymerization initiator for UV curing. Add 3.0 parts by mass of a photoinitiator and 2.0 parts by mass of a fluorine-based antifouling agent (manufactured by Shin-Etsu Chemical Co., Ltd., KY-1203) to isopropyl alcohol so that the total solid concentration is 3.5% by mass. The mixture was stirred in a paint shaker for 40 minutes to obtain HC Composition 2.

Next, using a triacetyl cellulose (TAC) film (manufactured by Fuji Film, TJ40) with a thickness of 60 μm as a transparent support, HC composition 1 was applied to one side of the transparent support using a bar coater, and a dryer was used. It was dried at 100°C for 1 minute. Using a high-pressure mercury UV device, the coating film is irradiated with ultraviolet rays in a nitrogen atmosphere (oxygen concentration 500 ppm or less) so that the cumulative exposure amount is 200 mJ/ ^cm2 , and the coating film is cured to form an anti-glare layer. did. The coating amount of HC composition 1 was adjusted so that the film thickness after curing was 5 μm.

Next, HC composition 2 was applied onto the anti-glare layer using a bar coater, and dried in a dryer at 100° C. for 1 minute. Using a high-pressure mercury UV device, the coating film was irradiated in a nitrogen atmosphere (oxygen concentration of 500 ppm or less) with a cumulative exposure dose of 200 mJ/cm ² to harden the coating film and form a low refractive index layer. . The coating amount of HC composition 2 was adjusted so that the optical film thickness nd (nd = refractive index n x film thickness d (nm)) after curing was 550/4 nm.

(Example 2a)
An optical laminate was produced in the same manner as in Example 1a, except that no fluorine-based antifouling agent was added to HC composition 2 and 47.0 parts by mass of PETA was blended.

(Example 3a)
The blending amount of PETA in HC composition 1 was 90.0 parts by mass, 2.0 parts by mass of a fluorine-based antifouling agent (manufactured by Shin-Etsu Chemical Co., Ltd., KY-1203) was added, and a low refractive index layer was not formed. Except for this, an optical laminate was produced in the same manner as in Example 1a.

(Example 4a)
An optical laminate was produced in the same manner as in Example 1a, except that the low refractive index layer was not formed.

(Example 5a)
An optical laminate was produced in the same manner as in Example 1a, except that in HC Composition 1, the time for dispersing organic particles using a paint shaker and the stirring time for the coating liquid were both 60 minutes.

(Example 6a)
An optical laminate was produced in the same manner as in Example 1a, except that the time for dispersing the organic fine particles using the paint shaker in HC Composition 1 was 60 minutes.

(Example 7a)
An optical laminate was produced in the same manner as in Example 1a, except that the organic fine particles in HC Composition 1 were changed to organic fine particles (manufactured by Techpolymer, SSX-103) with an average particle size of 3.0 μm.

(Example 8a)
An optical laminate was produced in the same manner as in Example 7a, except that no fluorine-based antifouling agent was added to HC composition 2 and the amount of PETA was 47.0 parts by mass.

(Example 9a)
The blending amount of PETA in HC composition 1 was 90.0 parts by mass, 2.0 parts by mass of a fluorine-based antifouling agent (manufactured by Shin-Etsu Chemical Co., Ltd., KY-1203) was added, and a low refractive index layer was not formed. Except for this, an optical laminate was produced in the same manner as in Example 7a.

(Example 10a)
An optical laminate was produced in the same manner as in Example 7a, except that the low refractive index layer was not formed.

(Example 11a)
An optical laminate was produced in the same manner as in Example 1a, except that the coating amount of HC Composition 1 was changed so that the film thickness after curing was 6.0 μm.

(Example 12a)
An optical laminate was produced in the same manner as in Example 11a, except that no fluorine-based antifouling agent was added to HC composition 2 and the amount of PETA was 47.0 parts by mass.

(Example 13a)
The blending amount of PETA in HC composition 1 was 90.0 parts by mass, 2.0 parts by mass of a fluorine-based antifouling agent (manufactured by Shin-Etsu Chemical Co., Ltd., KY-1203) was added, and a low refractive index layer was not formed. Except for this, an optical laminate was produced in the same manner as in Example 11a.

(Example 14a)
An optical laminate was produced in the same manner as in Example 11a, except that the low refractive index layer was not formed.

(Example 1b-1)
5.0 parts by mass of PETA of HC composition 1, particles of an antibacterial and antiviral agent (silver-based antibacterial and antiviral agent (manufactured by Dainichiseika Chemical Co., Ltd.: PTC-NT (ST)) were crushed with a bead mill and subjected to dispersion treatment, average An optical laminate was produced in the same manner as in Example 1a, except that the particles were replaced with particles (particle size: 0.5 μm).

(Example 1b-2)
Examples except that 10.0 parts by weight of PETA in HC composition 1 was replaced with an antibacterial and antiviral agent (a quaternary ammonium salt-based antibacterial and antiviral agent (manufactured by Kobayashi Pharmaceutical: KOBA-GUARD, non-particle)) An optical laminate was produced in the same manner as 1a.

(Example 1c)
Optical lamination was performed in the same manner as in Example 1a, except that the transparent support in Example 1b-1 was replaced with a 75 μmm thick polyethylene terephthalate (PET) film (Lumirror #75-U34, manufactured by Toray Industries). The body was created.

(Examples 2b to 14b)
5.0 parts by mass of PETA of HC composition 1, particles of an antibacterial and antiviral agent (silver-based antibacterial and antiviral agent (manufactured by Dainichiseika Chemical Co., Ltd.: PTC-NT (ST)) were crushed with a bead mill and subjected to dispersion treatment, average Optical laminates were produced in the same manner as in Examples 2a to 14a, except that the particles were replaced with particles (particle size: 0.5 μm).

(Comparative example 1)
An optical laminate was produced in the same manner as in Example 1a, except that the coating amount of HC composition 1 was changed so that the film thickness after curing was 4.0 μm.

(Comparative example 2)
An optical laminate was produced in the same manner as in Example 1a, except that the coating amount of HC Composition 1 was changed so that the film thickness after curing was 7.0 μm.

(Comparative example 3)
An optical laminate was produced in the same manner as in Example 1a, except that the organic fine particles in HC Composition 1 were changed to organic fine particles (manufactured by Techpolymer, SSX-105) with an average particle size of 5.0 μm.

(Comparative example 4)
An optical laminate was produced in the same manner as in Example 1a, except that the organic fine particles in HC Composition 1 were changed to organic fine particles (manufactured by Techpolymer, SSX-102) with an average particle size of 2.5 μm.

(Comparative example 5)
The optical composition was prepared in the same manner as in Example 1a, except that the amount of PETA in HC Composition 1 was 90.0 parts by mass, and the amount of organic fine particles (manufactured by Techpolymer, SSX-2035) was 7.0 parts by mass. A laminate was produced.

(Comparative example 6)
An optical laminate was produced in the same manner as in Example 1a, except that the amount of PETA in HC Composition 1 was 94.0 parts by mass, and the amount of organic fine particles was 3.0 parts by mass.

(Comparative example 7)
An optical laminate was produced in the same manner as in Example 1a, except that the time for dispersing organic particles using a paint shaker in HC Composition 1 was changed to 20 minutes.

(Comparative example 8)
An optical laminate was produced in the same manner as Comparative Example 7, except that no fluorine-based antifouling agent was added to HC Composition 2 and the amount of PETA was 47.0 parts by mass.

(Comparative example 9)
The blending amount of PETA in HC composition 1 was 90.0 parts by mass, 2.0 parts by mass of a fluorine-based antifouling agent (manufactured by Shin-Etsu Chemical Co., Ltd., KY-1203) was added, and a low refractive index layer was not formed. An optical laminate was produced in the same manner as Comparative Example 7 except for this.

(Comparative example 10)
An optical laminate was produced in the same manner as Comparative Example 7 except that the low refractive index layer was not formed.

(Comparative Example 11)
An optical laminate was produced in the same manner as in Example 1a, except that in HC Composition 1, the time for dispersing organic particles using a paint shaker and the stirring time for the coating liquid were changed to 80 minutes.

(Comparative example 12)
An optical laminate was produced in the same manner as Comparative Example 11, except that no fluorine-based antifouling agent was added to HC Composition 2 and the amount of PETA was 47.0 parts by mass.

(Comparative example 13)
The blending amount of PETA in HC composition 1 was 90.0 parts by mass, 2.0 parts by mass of a fluorine-based antifouling agent (manufactured by Shin-Etsu Chemical Co., Ltd., KY-1203) was added, and a low refractive index layer was not formed. An optical laminate was produced in the same manner as Comparative Example 11 except for this.

(Comparative example 14)
An optical laminate was produced in the same manner as Comparative Example 11 except that the low refractive index layer was not formed.

The optical laminates according to each Example and each Comparative Example were evaluated as follows.

<Evaluation 1: Surface unevenness shape>
(Acquisition of 3D data)
Using Vertscan (manufactured by Ryoka System Co., Ltd., R3300H Lite), three-dimensional data of the uneven shape of the outermost surface of the optical laminate was measured by an optical interference method. The measurement conditions are as follows. The height of the unevenness was based on the lowest position within the measurement range.
・Camera model: Sony HR-50 1/3
・Objective lens magnification: 5XTI
・Lens barrel: 1X
・Zoom lens: 1X
・Light source: 530white
・Wavelength filter: 520nm
・Measurement device: Piezo ・Measurement mode: Phase
・Scan speed: 4μm/sec
・Scan range: 10μm to -10μm
・Number of effective pixels: 0%
・Measurement range: 940.8μm x 705.6μm, 640pixel x 480pixel
・XY direction resolution: 1 pixel 1.47 μm

(FFT analysis)
FFT analysis was performed using free software "ImageJ 1.53h" under Windows (registered trademark) 10 environment. The steps are as follows.
1. The three-dimensional data was converted to TIFF image data in which the height is the pixel value.
2. FFT was performed with reference to the original three-dimensional data values (height measurements). The image size after FFT processing was 1024 pixels x 1024 pixels.
3. The image after the FFT processing was processed to restore the power spectrum intensity to the actual measured value.
4. In the processed image, a range of ±20 pixels on the positive X axis passing through the origin was specified, and the power spectrum intensity was output.
5. The X coordinate of the output power spectrum was converted into a spatial frequency f based on the pixel size of the original three-dimensional data.
6. From the calculated spatial frequency, the average value (A ~C value) was calculated.

<Evaluation 2. Optical properties>
The optical properties of the optical laminate were evaluated according to the following criteria based on the evaluation of haze, antiglare, and reflectance shown below.
◎: There is one or more evaluations ◎ for haze, anti-glare property, reflectance, and the remaining evaluations are 〇〇: All evaluations for haze, anti-glare property, reflectance are 〇×: Haze, anti-glare property, reflectance There is one or more × rating in

(Haze)
The haze was measured using a haze meter (NDH7000, manufactured by Nippon Denshoku Kogyo Co., Ltd.) in accordance with the haze test method of JIS K 7136, a method for testing optical properties of plastics. The evaluation criteria for optical properties are as follows.
◎: Haze is 6% or more and less than 8% 〇: Haze is 4% or more and less than 6%, or 8% or more and less than 10% ×: Haze is less than 4% or 10% or more

(Anti-glare)
FIG. 3 is a diagram showing a method for evaluating anti-glare properties, and FIG. 4 is a diagram showing an example of evaluating anti-glare properties.

The obtained optical laminate was bonded to a blackboard using an optical adhesive so that the functional side faced the surface. In addition, three-wavelength fluorescent lamps and optical laminates were installed so that the light hits the functional surfaces perpendicularly. Observe the surface of the optical laminate from the direction in which the line connecting the viewpoint and the image of the three-wavelength fluorescent lamp reflected on the functional surface is 70° to the perpendicular drawn from the three-wavelength fluorescent lamp to the functional surface, and observe the following. Anti-glare properties were evaluated according to standards.
〇: The outline of the three-wavelength fluorescent lamp can be seen, but the edges are blurry and unclear.

(reflectance)
The spectral reflectance of the functional layer surface of the obtained optical laminate at an incident angle of 5° was measured using an automatic spectrophotometer (U-4100, manufactured by Hitachi, Ltd.), and evaluated according to the following criteria. During the measurement, a matte black paint was applied to the back surface of the TAC film (the surface on which no functional layer was formed) to prevent reflection.
◎: Reflectance is less than 0.5% 〇: Reflectance is 0.5% or more and less than 1% ×: Reflectance is 1% or more

<Rating 3. Fingerprint wiping performance>
The optical laminate was attached to a blackboard using an optical adhesive so that the functional side faced the surface. The artificial leather coated with the olive oil reagent was pressed onto the functional surface to coat it with olive oil, and the attached olive oil was repeatedly wiped off using tissue paper (Scotty (registered trademark), manufactured by Nippon Paper Kracie Co., Ltd.) under a load of 1 kg. After each wipe, the reflection spectrum of the olive oil-attached area was measured using a spectrophotometer (CM-2500d, manufactured by Konica Minolta). The measurement conditions are as follows.
・Measurement diameter: Φ8mm
・Item: SCI/SCE
・Light source: D65
・UV setting: 100%
・Observation field of view: 10°
The color difference ΔE*ab before and after wiping off the olive oil was calculated, and the number of times of wiping when the color difference ΔE*ab became 0.5 or less was used as an evaluation value, and the evaluation was made according to the following criteria.
◎: The number of times of wiping is less than 5 times (fingerprint wiping performance is very good)
○: Number of times of wiping is 5 or more and less than 10 times (good fingerprint wiping performance)
△: The number of times of wiping is 10 or more and less than 30 times (difficult to wipe off fingerprints)
×: The number of times of wiping is 30 times or more (fingerprints are very difficult to wipe off or cannot be wiped off)

<Rating 4. Antibacterial>
Antibacterial tests against Escherichia coli and Staphylococcus aureus were conducted on the functional surface of the optical laminate in accordance with JIS Z 2801. A polyethylene film was used as an unprocessed sample and evaluated according to the following criteria.
○: Antibacterial activity value of both E. coli and Staphylococcus aureus is 2.0 or more ×: Antibacterial activity value of at least one of E. coli and Staphylococcus aureus is less than 2.0

<Rating 5. Antiviral>
Antiviral tests against influenza A virus and feline calicivirus were conducted on the functional surface of the optical laminate in accordance with ISO 21702. A polyethylene film was used as an unprocessed sample and evaluated according to the following criteria.
○: Antiviral activity value of at least one of influenza A virus and feline calicivirus is 2.0 or more ×: Antiviral activity value of both influenza A virus and feline calicivirus is less than 2.0

<Rating 6. Scratch resistance>
The obtained optical laminate was set in a Gakushin type abrasion fastness tester (AB-301, manufactured by Tester Sangyo Co., Ltd.), and 500 g/cm ² of steel wool (Bonstar #0000) was applied to the surface of the optical laminate. A scratch resistance test was conducted by making contact with pressure and reciprocating 10 times. After the scratch resistance test, the surface of the optical laminate was visually observed and evaluated according to the following criteria.
〇: No scratches ×: One or more scratches

<Rating 7. Water vapor transmission rate>
The moisture permeability of the obtained optical film and the moisture permeability of the above-mentioned transparent base material were measured at 40°C in accordance with the moisture permeability test method (cup method) for moisture-proof packaging materials specified in JIS Z 0208:1976. It was measured under the condition of 90RH% and evaluated according to the following criteria.
〇: Moisture permeability value 150g/(m ²・day) or less ×: Moisture permeability value exceeding 150g/(m ²・day)

Tables 1 to 3 show the evaluation results.

As shown in Table 1, the optical laminates according to Examples 1a to 14a satisfy conditions (1) to (3) in A to C, have excellent optical properties and fingerprint wiping properties, and have excellent scratch resistance. was also good. The fingerprint wiping property was good even when no antifouling agent was added to the outermost functional layer, but it became very good when an antifouling agent was added to the outermost functional layer. In addition, the optical laminates according to Examples 1b-1, 1b-2, 1c, and 2b to 14b also satisfy conditions (1) to (3) in A to C, and have excellent optical properties, fingerprint wiping properties, and resistance. It had excellent scratch resistance. In addition, the optical laminates according to Examples 1b-1, 1b-2, 1c, and 2b to 14b had both antibacterial and antiviral properties because the antibacterial and antiviral agent was contained in the antiglare layer. . The optical laminate according to Example 1c had a reduced water vapor permeability because a PET film with low moisture permeability was used as the transparent support.

On the other hand, in the optical laminates according to Comparative Examples 1 to 14, one or more of A to C did not satisfy the above conditions, and the evaluation of one or both of optical properties and fingerprint wiping properties was low.

From the above, it was confirmed that by simultaneously satisfying conditions (1) to (3) for A to C described above, an optical laminate with excellent optical properties and fingerprint wiping properties can be realized.

The present invention can be used as an optical film provided on the outermost surface of an image display device.

1 Optical laminate 2 Transparent support 3 Anti-glare layer 4 Low refractive index layer

Claims

An optical laminate having an uneven shape on the outermost surface,
An optical laminate characterized by simultaneously satisfying the following conditions (1) to (3).
40,000≦A≦300,000 (1)
300≦B≦1,000 (2)
30≦C≦500 (3)
Here, the three-dimensional data of the height of the unevenness measured by the optical interference method or the contact method is converted into first image data whose pixel value is the height of the unevenness, and the first image data is subjected to fast Fourier transformation. Convert it to a second image by , and calculate the spatial frequency f of the X coordinate of the power spectrum of the image that passes through the origin and within a range of ±20 pixels on the positive X axis and Y axis direction. In the case that
A: average value of power spectrum intensity in the range of 0<f≦100cycle/mm,
B: average value of power spectrum intensity in the range of 100cycle/mm<f≦200cycle/mm,
C: Average value of power spectrum intensity in the range of 200 cycles/mm<f≦300 cycles/mm.
The optical laminate includes a transparent support and a first functional layer laminated on at least one surface of the transparent support, and the uneven shape of the outermost surface is formed by the first functional layer. The optical laminate according to claim 1, characterized in that:
The optical laminate according to claim 2, further comprising a second functional layer having a refractive index lower than the refractive index of the first functional layer on the first functional layer.
The optical laminate according to claim 2, wherein the first functional layer contains an antifouling agent.
The optical laminate according to claim 3, wherein the second functional layer contains an antifouling agent.
The optical laminate according to claim 2, wherein the first functional layer contains a fluorine-containing compound or a silicone compound.
The optical laminate according to claim 3, wherein the second functional layer contains a fluorine-containing compound or a silicone compound.
The optical laminate according to claim 2, wherein the first functional layer contains an antibacterial agent and/or an antiviral agent.
The optical laminate according to claim 3, wherein the first functional layer or the second functional layer contains an antibacterial agent and/or an antiviral agent.
The optical laminate according to claim 2, wherein the transparent support is made of a material with low moisture permeability.
An image display device comprising the optical laminate according to any one of claims 1 to 10.