Optical laminate and display device using same

Abstract

Provided are: an optical laminate which can be suitably used as a constituent member of a flexible display or the like, is unsusceptible to defects even when curved at a small radius of curvature, and can achieve low reflectance and high luminance in a display device; and a display device using the same. This optical laminate comprises: a sheet-like base material; a functional layer formed on a first surface side of the base material; and a colored layer formed on a second surface side of the base material. The tensile elongation at break measured in accordance with JIS K 7127 (7161) satisfies the following conditions in both the longitudinal direction (MD) and the width direction (TD).　|Lb−La|<|La×0.1| where La is the tensile elongation at break (%) in a state in which the functional layer is formed on the base material and Lb is the tensile elongation at break (%) in a state in which the functional layer and the colored layer are formed on the base material.

Description

Optical laminate and display device using the same

[0001] The present invention relates to an optical laminate and a display device using the same.

[0002] Metal electrodes and wiring are formed within the display surface of a self-luminous display device such as an organic EL display device. These metal electrodes and wiring reflect light incident from the outside (i.e., external light), which can easily lead to deterioration in display quality, such as a decrease in contrast. To improve display quality, a configuration has been proposed in which a polarizing plate and a phase retardation plate (circular polarizing plate) are provided. However, when light emitted from the display device passes through the circular polarizing plate and is released to the outside, most of the light is lost, which can easily lead to increased power consumption and a shortened device lifespan.

[0003] As a display device having a different configuration from the above, for example, Patent Document 1 describes a configuration including an optical filter containing a dye that selectively absorbs a predetermined wavelength band. The optical filter described in Patent Document 1 selectively absorbs light emitted from the display device, particularly light in a wavelength band that reduces color purity, thereby reducing the loss of light necessary for displaying the three primary colors and improving the visibility of the displayed image.

[0004] Furthermore, with the increasing adoption of flexible displays in recent years, the components that make up display devices are increasingly being required to have bending resistance in addition to the optical properties and durability that have traditionally been required. While circular polarizers are difficult to make thin due to their own thickness, optical filters can be made by adding them to the functional layer, making them highly compatible with flexible displays.

[0005] Japanese Patent Application Laid-Open No. 2019-56865

[0006] A hard coat film having surface protection properties and flex resistance is used on the surface of a flexible display. When an optical filter layer (colored layer) that selectively absorbs a predetermined wavelength band is provided on such a hard coat film, the optical filter layer is provided in a layer configuration, for example, optical filter layer / substrate / functional layer or optical filter layer / functional layer / substrate / functional layer, from the inside of the display when the flexible display is constructed, taking into consideration reliability such as light resistance and heat resistance.

[0007] When a conventional optical laminate is bent so that the radius of curvature gradually decreases, fine cracks tend to occur in the colored layer on the outer side of the bent portion, even at a relatively large radius of curvature. When considering application to bendable or foldable display devices and the like, the optical laminate is required to be less likely to develop defects even when bent at a small radius of curvature.

[0008] Therefore, an object of the present invention is to provide an optical laminate that can be suitably used as a component of a flexible display or the like, that is less likely to cause defects even when bent with a small radius of curvature, and that can achieve low reflectance and high brightness in the display device, and a display device using the same.

[0009] The optical laminate according to the present invention comprises a sheet-like substrate, a functional layer formed on a first surface of the substrate, and a colored layer formed on a second surface of the substrate, and the tensile elongation at break measured in accordance with JIS K 7127 (7161) satisfies the following condition in both the longitudinal direction (MD) and the transverse direction (TD): |Lb - La| < |La x 0.1|, where, La: tensile elongation at break (%) when the functional layer is formed on the substrate, and Lb: tensile elongation at break (%) when the functional layer and colored layer are formed on the substrate.

[0010] A display device according to the present invention includes the above optical laminate.

[0011] According to the present invention, it is possible to provide an optical laminate that can be suitably used as a component of a flexible display or the like, that is less likely to cause defects even when bent with a small radius of curvature, and that can achieve low reflectance and high brightness in a display device, and a display device using the same.

[0012] Fig. 1 is a cross-sectional view showing a schematic configuration of a display device according to a first embodiment, and Fig. 2 is a cross-sectional view showing a schematic configuration of a display device according to a second embodiment.

[0013] 1 and 2 are cross-sectional views showing the schematic configurations of display devices according to the first and second embodiments, respectively, and the upper sides in Fig. 1 and Fig. 2 correspond to the observation side when observing a displayed image on the display device. In addition, when the display device is a flexible display, the upper side in Fig. 1 and Fig. 2 is the surface that becomes the inside when bent (folded).

[0014] The display device 100 shown in Fig. 1 includes a display panel 8 and an optical laminate 10 provided on the display surface side of the display panel 8. The display panel 8 is, for example, a self-luminous display panel such as an organic EL panel or a micro LED panel, and metal electrodes, metal wiring, etc. are provided within the display surface. The optical laminate 10 includes a substrate 1, a functional layer 2 laminated on a first surface side (observation side) of the substrate 1, and a colored layer 3 laminated on a second surface side (display panel 8 side) of the substrate 1. The optical laminate 10 is bonded to the display panel 8 so that the colored layer 3 faces the display panel 8.

[0015] 2 includes a display panel 8 and an optical laminate 20 provided on the display surface side of the display panel 8. The optical laminate 20 includes a substrate 1, a functional layer 2 laminated on a first surface side (observation side) of the substrate 1, and an ultraviolet absorbing layer 4 and a colored layer 3 laminated on a second surface side (display panel 8 side) of the substrate 1. The optical laminate 20 is bonded to the display panel 8 so that the colored layer 3 faces the display panel 8.

[0016] A portion of the external light incident on the display panel 8 is reflected by the metal electrodes and metal wiring of the display panel 8. Light reflected within the display devices 100 and 200 impairs the contrast and visibility of the image displayed on the display panel 8, and thus, conventionally, a circular polarizer has been used to reduce the reflected light on the surface of the display panel 8. The optical laminates 10 and 20 according to the present embodiment include a coloring layer 3 containing a dye that absorbs light in a specific wavelength range in the visible light region, and therefore absorb a portion of the incident external light. The remaining portion of the external light not absorbed by the coloring layer 3 is reflected by the display panel 8, while a portion of the reflected light is absorbed by the coloring layer 3. As a result, the internal reflectance of the external light is significantly reduced. Furthermore, by ensuring that the absorption wavelength range of the dye contained in the coloring layer 3 does not overlap with the maximum wavelength of the light emitted by the display panel 8, a decrease in the luminance of the three primary colors emitted from the display panel 8 can be suppressed compared to when a circular polarizer is provided, and the visibility of the image displayed on the display panel 8 can be improved.

[0017] Furthermore, the tensile elongation at break of the optical laminates 10 and 20 according to the present invention satisfies the following condition in both the longitudinal direction (MD) and the width direction (TD). The tensile elongation at break is a value measured in accordance with JIS K 7127 (7161). |Lb - La| < |La x 0.1| Where, La: tensile elongation at break in a state where a functional layer is formed on a substrate (before forming a colored layer), Lb: tensile elongation at break in a state where a functional layer and a colored layer are formed on a substrate (after forming a colored layer).

[0018] When the optical laminate 10 or 20 is applied to a foldable display device, the functional layer 2 becomes the innermost layer of the bent portion when folded, and the colored layer 3 becomes the outermost layer of the bent portion. Tensile stress concentrates at the bent portion of the colored layer 3, which may cause cracks to occur in the colored layer 3. In the optical laminates 10 and 20 according to the present invention, the absolute value of the difference in tensile elongation at break before and after lamination of the colored layer 3 is less than 10% of the tensile elongation at break before the formation of the colored layer 3, and therefore the colored layer 3 has high conformability to the substrate 1. Therefore, even when a bending load is applied due to folding, local deformation of the optical laminates 10 and 20 is suppressed, and the occurrence of defects such as cracks is suppressed.

[0019] Hereinafter, each layer included in the optical laminates 10 and 20 will be described in detail.

[0020] (Substrate) The substrate 1 is a film that serves as the base of the optical laminates 10 and 20. The substrate 1 is selected from a material that has excellent visible light transmittance and mechanical strength required for flexible displays. Examples of materials for forming the substrate 1 include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyimide (PI). The thickness of the substrate 1 is preferably 10 to 100 μm, and more preferably 20 to 60 μm. When the thickness of the substrate 1 is equal to or less than the upper limit, the display device can be made lighter, which is advantageous for making it thinner. When the thickness of the substrate 1 is equal to or greater than the lower limit, the strength of the optical laminate can be further increased.

[0021] (Functional Layer) The functional layer 2 is a layer for adjusting the surface hardness and optical properties of the optical laminates 10 and 20, and may include one or more of a hard coat layer, an anti-reflection layer including a high refractive index layer or a low reflectance layer, and an anti-glare layer.

[0022] (Hard Coat Layer) The hard coat layer is a layer for imparting hardness to the optical laminates 10 and 20, and can be formed by applying and curing a hard coat layer-forming composition containing an active energy ray-curable resin, a photopolymerization initiator, and a solvent. The thickness of the hard coat layer is not particularly limited, but is preferably 3 to 10 μm. If the thickness of the hard coat layer is less than 3 μm, the hard coat layer may not have sufficient hardness. If the thickness of the hard coat layer 22 exceeds 10 μm, this is not preferable because it is disadvantageous for thinning the optical laminates 10 and 20. However, the film thickness of the hard coat layer can be appropriately set depending on the surface hardness and overall thickness required for the optical laminate.

[0023] The active energy ray-curable resin is a resin that is polymerized and cured by irradiation with active energy rays such as ultraviolet rays or electron beams, and for example, a monofunctional, difunctional, trifunctional or higher functional (meth)acrylate monomer can be used. In this specification, "(meth)acrylate" is a general term for both acrylate and methacrylate, and "(meth)acryloyl" is a general term for both acryloyl and methacryloyl.

[0024] Examples of monofunctional (meth)acrylate compounds include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, glycidyl (meth)acrylate, acryloylsulfoline, N-vinylpyrrolidone, tetrahydrofurfuryl acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and 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, phosphate (meth)acrylate, ethylene oxide-modified phosphate (meth)acrylate, phenoxy (meth)acrylate, ethylene oxide-modified phenoxy (meth)acrylate, propylene oxide ethylene 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-2-hydroxypropyl phthalate, ) acryloyloxyethyl hydrogen phthalate, 2-(meth)acryloyloxypropyl 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)acrylates such as adamantyl acrylate having a monovalent mono(meth)acrylate derived from adamantanediol, etc.

[0025] Examples of bifunctional (meth)acrylate compounds include di(meth)acrylates such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, 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, neopentyl glycol di(meth)acrylate, ethoxylated neopentyl glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and hydroxypivalic acid neopentyl glycol di(meth)acrylate.

[0026] Examples of trifunctional or higher functional (meth)acrylate compounds include tri(meth)acrylates such as trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, tris-2-hydroxyethyl isocyanurate tri(meth)acrylate, and glycerin tri(meth)acrylate, as well as trifunctional (meth)acrylate compounds such as pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, and ditrimethylolpropane tri(meth)acrylate. and polyfunctional (meth)acrylate compounds having three or more functional groups such as pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, ditrimethylolpropane penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and ditrimethylolpropane hexa(meth)acrylate; and polyfunctional (meth)acrylate compounds in which a portion of these (meth)acrylates is substituted with an alkyl group or ε-caprolactone.

[0027] Urethane (meth)acrylates can also be used as the active energy ray-curable resin. Examples of urethane (meth)acrylates include those obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer, and then reacting the resulting product with a (meth)acrylate monomer having a hydroxyl group.

[0028] 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 urethane prepolymer, pentaerythritol triacrylate isophorone diisocyanate urethane prepolymer, and dipentaerythritol pentaacrylate isophorone diisocyanate urethane prepolymer.

[0029] The active energy ray-curable resins described above may be used alone or in combination of two or more. In addition, the active energy ray-curable resins described above may be monomers in the composition for forming a hard coat layer, or may be partially polymerized oligomers.

[0030] Examples of photopolymerization initiators that can be used in the hard coat layer-forming composition include 2,2-ethoxyacetophenone, 1-hydroxycyclohexylphenyl ketone, dibenzoyl, benzoin, benzoin methyl ether, benzoin ethyl ether, p-chlorobenzophenone, p-methoxybenzophenone, Michler's ketone, acetophenone, and 2-chlorothioxanthone. One of these may be used alone, or two or more may be used in combination.

[0031] Examples of solvents used in the hard coat layer-forming composition include ethers such as dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5-trioxane, tetrahydrofuran, anisole, and phenetole, ketones such as acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, and methylcyclohexanone, esters such as ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, n-pentyl acetate, and γ-butyrolactone, and cellosolves such as methyl cellosolve, cellosolve, butyl cellosolve, and cellosolve acetate. These may be used alone or in combination of two or more.

[0032] The composition for forming a hard coat layer may contain metal oxide fine particles for the purpose of adjusting the refractive index or imparting hardness. Examples of metal oxide fine particles include zirconium oxide, titanium oxide, niobium oxide, antimony trioxide, antimony pentoxide, tin oxide, indium oxide, indium tin oxide, antimony tin oxide, and zinc oxide.

[0033] The composition for forming a hard coat layer may also contain any of silicon oxides, fluorine-containing silane compounds, fluoroalkyl silazanes, fluoroalkyl silanes, fluorine-containing silicon compounds, and perfluoropolyether group-containing silane coupling agents, which impart water repellency and / or oil repellency and enhance antifouling properties.

[0034] (Antireflection Layer) The antireflection layer is a layer that suppresses reflection of external light by canceling out light reflected at different interfaces. The antireflection layer can be composed of, for example, a laminate in which a high refractive index layer and a low refractive index layer are laminated in this order from the substrate 1 side, or a low refractive index layer laminated on the substrate 1.

[0035] The high refractive index layer can be formed by applying and curing a composition for forming a high refractive index layer containing an active energy ray-curable resin, high refractive index fine particles, a photopolymerization initiator, and a solvent. Examples of the high refractive index fine particles include metal oxide fine particles such as zirconium oxide, titanium oxide, niobium oxide, antimony trioxide, antimony pentoxide, tin oxide, indium oxide, indium tin oxide, antimony tin oxide, and zinc oxide. The active energy ray-curable resin, photopolymerization initiator, and solvent can be the same compounds as those exemplified for the hard coat layer.

[0036] The thickness of the high refractive index layer is not particularly limited, but is preferably 10 to 300 nm, and the refractive index of the high refractive index layer is preferably 1.55 to 2.20.

[0037] The low refractive index layer can be formed by applying and curing a composition for forming a low refractive index layer containing an active energy ray curable resin, a photopolymerization initiator, and a solvent. The composition for forming a low refractive index layer contains LiF, MgF, 3NaF.AlF for adjusting the refractive index. ３ Alternatively, fine particles such as AlF or silica fine particles may be blended. Furthermore, the use of silica fine particles having voids inside the particles, such as porous silica fine particles or hollow silica fine particles, is effective in lowering the refractive index of the low refractive index layer. The active energy ray-curable resin, photopolymerization initiator, and solvent may be the same compounds as those exemplified for the hard coat layer.

[0038] The thickness of the low refractive index layer is not particularly limited, but is preferably 40 to 300 nm, and the refractive index of the low refractive index layer 23 is preferably 1.25 to 1.40.

[0039] The low refractive index layer may contain any of silicon oxide, fluorine-containing silane compounds, fluoroalkyl silazane, fluoroalkyl silane, fluorine-containing silicon compounds, and perfluoropolyether group-containing silane coupling agents, which can impart water and / or oil repellency to the low refractive index layer, thereby improving the antifouling properties.

[0040] The antireflection layer may be formed by laminating a medium refractive index layer, a high refractive index layer, and a low refractive index layer in this order on the substrate 1. The medium refractive index layer may have a refractive index between that of the high refractive index layer and that of the low refractive index layer. The medium refractive index layer may be formed by applying to the substrate 1 a composition for forming a medium refractive index layer, the refractive index of which is adjusted by adding metal oxide fine particles described in the high refractive index layer to the active energy ray-curable resin, photopolymerization initiator, and solvent described in the hard coat layer, and then curing the composition.

[0041] (Antiglare Layer) The antiglare layer has fine irregularities on its surface, and the irregularities scatter external light, thereby reducing the glare of external light. The antiglare layer can be formed by applying and curing an antiglare layer-forming composition containing an active energy ray-curable resin, a photopolymerization initiator, and a solvent, and optionally adding organic fine particles and / or inorganic fine particles. The active energy ray-curable resin, photopolymerization initiator, and solvent can be the same compounds as those exemplified for the hard coat layer.

[0042] The thickness of the antiglare layer is not particularly limited, but is preferably 3 to 10 μm.

[0043] The organic fine particles used in the composition for forming an antiglare layer are a material that mainly forms fine irregularities on the surface of the antiglare layer and provides the function of diffusing external light. Examples of organic fine particles that can be used include resin particles made of a light-transmitting resin material such as acrylic resin, polystyrene resin, styrene-(meth)acrylic acid ester copolymer, polyethylene resin, epoxy resin, silicone resin, polyvinylidene fluoride, and polyethylene fluoride resin. Two or more types of resin particles made of different materials (refractive indexes) may be mixed and used to adjust the refractive index and dispersibility of the resin particles.

[0044] The inorganic fine particles used in the antiglare layer-forming composition are primarily materials for controlling the sedimentation and aggregation of organic fine particles in the antiglare layer. Examples of inorganic fine particles that can be used include silica fine particles, metal oxide fine particles, and various mineral fine particles. Examples of silica fine particles include colloidal silica and silica fine particles surface-modified with reactive functional groups such as (meth)acryloyl groups. Examples of metal oxide fine particles that can be used include alumina, zinc oxide, tin oxide, antimony oxide, indium oxide, titania, and zirconia. Examples of mineral fine particles that can be used include mica, synthetic mica, vermiculite, montmorillonite, iron-montmorillonite, bentonite, beidellite, saponite, hectorite, stevensite, nontronite, magadiite, ilealite, kanemite, layered titanic acid, smectite, and synthetic smectite. The mineral fine particles may be either natural or synthetic (including substituted or derivative) materials, or a mixture of both. Among mineral fine particles, layered organic clay is more preferred. Layered organic clay refers to a swelling clay in which organic onium ions are introduced between the layers. The organic onium ions are not limited as long as they can be organized by utilizing the cation exchange properties of the swelling clay. When a layered organic clay mineral is used as the mineral fine particles, the above-mentioned synthetic smectite can be preferably used. Synthetic smectite has the function of increasing the viscosity of the coating liquid for forming the antiglare layer, suppressing the sedimentation of resin particles and inorganic fine particles, and adjusting the uneven shape of the surface of the optical functional layer.

[0045] The composition for forming an antiglare layer may contain any of silicon oxide, a fluorine-containing silane compound, a fluoroalkylsilazane, a fluoroalkylsilane, a fluorine-containing silicon compound, and a perfluoropolyether group-containing silane coupling agent. These materials can impart water repellency and / or oil repellency to the antiglare layer, thereby improving the antifouling properties.

[0046] (Colored Layer) The colored layer 3 is a layer for reducing light emitted from the display panel 8 and transmitted through the optical laminates 10 and 20, and reflected light that is external light reflected and re-emitted by the metal electrode members and reflective members of the display panel 10, and contains a dye for selectively absorbing a specific wavelength band of visible light. The colored layer can be formed by applying and curing a colored layer-forming composition that contains an active energy ray-curable resin, a dye, a photopolymerization initiator, and a solvent, and, if necessary, additives described below. The active energy ray-curable resin, photopolymerization initiator, and solvent used to form the colored layer 3 can be the compounds exemplified for the hard coat layer.

[0047] The coloring layer 3 contains one or more of the following coloring materials as a dye. By using a material having the following absorption characteristics, it is possible to make the coloring layer 3 absorb visible light in a wavelength range with relatively low emission intensity among the visible light emitted by the display panel 8: (1) A first coloring material having a maximum absorption wavelength in the range of 470 nm to 530 nm and a half-width of the absorption spectrum in the range of 15 nm to 45 nm; (2) A second coloring material having a maximum absorption wavelength in the range of 560 nm to 620 nm and a half-width of the absorption spectrum in the range of 15 nm to 55 nm; (3) A third coloring material having the lowest transmittance in the wavelength range of 400 nm to 780 nm in the range of 650 nm to 780 nm.

[0048] The thickness of the colored layer 3 is not particularly limited, but is preferably 0.5 to 10 μm. If the thickness of the colored layer 3 is less than 0.5 μm, the dye concentration contained in the colored layer 3 may be insufficient, resulting in insufficient light absorption. If the thickness of the colored layer 3 is less than 0.5 μm, increasing the dye concentration to ensure light absorption is undesirable because it causes abnormalities in the appearance. On the other hand, if the thickness of the colored layer 3 exceeds 10 μm, it is undesirable because it is disadvantageous for thinning the optical laminates 10 and 20.

[0049] The dye contained in the colored layer 3 can be a dye, pigment, nanometal, or the like. However, it is preferable to use one or more compounds selected from the group consisting of compounds having any of a porphyrin structure, a merocyanine structure, a phthalocyanine structure, an azo structure, a cyanine structure, a squarylium structure, a coumarin structure, a polyene structure, a quinone structure, a tetradiporphyrin structure, a pyrromethene structure, and an indigo structure, and metal complexes thereof. In particular, metal complexes having a porphyrin structure, a pyrromethene structure, or a phthalocyanine structure, or compounds having a squarylium structure, are more preferable due to their excellent reliability. These compounds may be contained alone or in combination of two or more. Furthermore, depending on the color adjustment and the desired optical properties, a dye having a wide half-width of the absorption spectrum may be used in combination.

[0050] The colored layer forming composition used to form the colored layer 3 is preferably a polymer having a structural unit represented by the following formula (1) that has the ability to capture radicals (radical scavenging ability).

[0051] In the above formula (1), R ａ represents a hydrogen atom, a halogen atom, a carboxyl group, a sulfo group, a cyano group, a hydroxy group, an alkyl group having 10 or less carbon atoms, an alkoxycarbonyl group having 10 or less carbon atoms, an alkylsulfonylaminocarbonyl group having 10 or less carbon atoms, an arylsulfonylaminocarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, an acylaminosulfonyl group having 10 or less carbon atoms, an alkoxy group having 10 or less carbon atoms, an alkylthio group having 10 or less carbon atoms, an aryloxy group having 10 or less carbon atoms, a nitro group, an alkoxycarbonyloxy group, an aryloxycarbonyloxy group, an acyloxy group having 10 or less carbon atoms, an acyl group having 10 or less carbon atoms, a carbamoyl group, a sulfamoyl group, an aryl group having 10 or less carbon atoms, a substituted amino group, a substituted ureido group, a substituted phosphono group, or a heterocyclic group; R ｂ represents a hydrogen atom or an alkyl group having 30 or less carbon atoms, and X represents a single bond, an ester group, an aliphatic alkyl chain having 30 or less carbon atoms, an aromatic chain, a polyethylene glycol chain, or a linking group formed by combining these, any of which may contain a spirodioxane ring.

[0052] R ａ R is preferably a hydrogen atom, a hydroxy group, or an alkyl group having 10 or less carbon atoms. The number of carbon atoms in the alkyl group is preferably 1 to 6, and more preferably 1 to 3. ｂ is preferably a hydrogen atom or an alkyl group having 10 or less carbon atoms. The number of carbon atoms in the alkyl group is preferably 1 to 6, and more preferably 1 to 3. X is preferably a single bond or an aliphatic alkyl chain having 30 or less carbon atoms. The number of carbon atoms in the aliphatic alkyl chain is preferably 10 or less, preferably 1 to 6, and more preferably 2 to 4.

[0053] The resin having an amine structure with radical scavenging ability mainly comprises a copolymer (the component with the largest mass %) of a structural unit represented by formula (1) and a copolymerization component having one of the repeating units described below. By using a copolymer, it is possible to control the compatibility with other components.

[0054] Examples of the repeating unit include (meth)acrylate repeating units, olefin repeating units, halogen atom-containing repeating units, styrene repeating units, vinyl acetate repeating units, and vinyl alcohol repeating units.

[0055] Examples of the (meth)acrylate repeating unit include a repeating unit derived from a (meth)acrylate monomer having a linear or branched alkyl group on the side chain, and a repeating unit derived from a (meth)acrylate monomer having a hydroxyl group on the side chain.

[0056] Examples of the repeating unit derived from a (meth)acrylate monomer having the linear or branched alkyl group on the side chain include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, and isopropyl (meth)acrylate. Examples of monomer-derived components include octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, myristyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, and octadecyl (meth)acrylate. These may be used alone or in combination of two or more. Among the above, (meth)acrylate-based repeating units having a linear or branched alkyl group having from 1 to 4 carbon atoms in the side chain are preferred.

[0057] Examples of the repeating unit derived from a (meth)acrylic monomer having a hydroxyl group in the side chain include components derived from monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, hydroxyphenyl (meth)acrylate, etc. These may be used alone or in combination of two or more.

[0058] Examples of the olefin repeating unit include components derived from olefin monomers such as ethylene, propylene, isoprene, butadiene, etc. These may be used alone or in combination of two or more.

[0059] Examples of the halogen atom-containing repeating unit include components derived from monomers such as vinyl chloride, vinylidene chloride, etc. These may be used alone or in combination of two or more.

[0060] Examples of styrene-based repeating units include components derived from styrene-based monomers such as styrene, α-methylstyrene, and vinyltoluene. These may be used alone or in combination of two or more. Examples of vinyl acetate-based repeating units include esters of saturated carboxylic acids and vinyl alcohol, such as vinyl acetate and vinyl propionate. These may be used alone or in combination of two or more. Examples of vinyl alcohol-based repeating units include vinyl alcohol, which may have a 1,2-glycol bond in the side chain.

[0061] The copolymer may have any of the structures of a random copolymer, an alternating copolymer, a block copolymer, and a graft copolymer. If the copolymer has a random structure, the manufacturing process and preparation with other components are easy. Therefore, a random copolymer is preferable to other copolymers.

[0062] Radical polymerization can be used as a polymerization method for obtaining the copolymer. Radical polymerization is preferred because it is easy to produce industrially. Radical polymerization may be a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a suspension polymerization method, or the like. For radical polymerization, it is preferable to use a solution polymerization method. By using a solution polymerization method, it is easy to control the molecular weight of the copolymer.

[0063] In the radical polymerization, the above-mentioned monomer may be diluted with a polymerization solvent, and then a polymerization initiator may be added to polymerize the monomer.

[0064] Examples of the polymerization solvent include ester-based solvents, alcohol ether-based solvents, ketone-based solvents, aromatic solvents, amide-based solvents, and alcohol-based solvents. Examples of the ester-based solvent include methyl acetate, ethyl acetate, n-butyl acetate, isobutyl acetate, t-butyl acetate, methyl lactate, and ethyl lactate. Examples of the alcohol ether-based solvent include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether, 3-methoxy-1-butanol, and 3-methoxy-3-methyl-1-butanol. Examples of the ketone-based solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Examples of the aromatic solvent include benzene, toluene, and xylene. Examples of the amide-based solvent include formamide and dimethylformamide. The alcohol solvent may be, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, s-butanol, t-butanol, diacetone alcohol, 2-methyl-2-butanol, etc. The above-mentioned polymerization solvents may be used alone or in combination of two or more.

[0065] The radical polymerization initiator may be, for example, a peroxide or an azo compound. The peroxide may be, for example, benzoyl peroxide, t-butyl peroxyacetate, t-butyl peroxybenzoate, di-t-butyl peroxide, etc. The azo compound may be, for example, azobisisobutyronitrile, azobisamidinopropane salt, azobiscyanovaleric acid (salt), 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], etc.

[0066] A polymer containing a structural unit represented by formula (1) having radical scavenging ability has the function of scavenging radicals when a dye undergoes oxidative degradation, suppressing autoxidation and thereby suppressing dye degradation (fading). When the amine structure having radical scavenging ability is a hindered amine structure having a molecular weight of 2000 or more, many molecules remain in the colored layer, which is preferable because a sufficient effect of suppressing fading can be obtained. In addition, this is preferable because it imparts flexibility to the coating film, which suppresses local deformation when bending is applied, thereby suppressing defects such as cracks.

[0067] In addition, as the active energy ray curable resin used to form the colored layer 3, monofunctional, difunctional, trifunctional or higher functional (meth)acrylate monomers, urethane (meth)acrylates, etc. can be used.

[0068] The content of the active energy ray-curable resin is preferably 50 to 70%, and more preferably 55 to 65%, of the total mass of all solids excluding the solvent in the colored layer-forming composition. The content of the structural unit represented by formula (1) is preferably 1 to 95 mol%, and more preferably 10 to 90 mol%, relative to the total molar amount of the monomers constituting the active energy ray-curable resin. When the content is equal to or greater than the above-mentioned lower limit, the effect of suppressing fading can be further enhanced. When the content is equal to or less than the above-mentioned upper limit, the colored layer 3 can be made more stretchable when bent.

[0069] The colored layer 3 preferably contains at least one of a peroxide decomposer and a singlet oxygen quencher as an additive. When the colored layer 3 contains either of these, deterioration of the dye can be further suppressed and the light absorption performance of the colored layer 3 can be maintained.

[0070] (Singlet Oxygen Quencher) A singlet oxygen quencher inactivates highly reactive singlet oxygen, which tends to cause oxidative degradation (fading) of dyes, and serves to suppress oxidative degradation (fading) of the dye. Examples of singlet oxygen quenchers include transition metal complexes, dyes, amines, phenols, and sulfides. Particularly preferred materials include dialkyl phosphates, dialkyl dithiocarbamates, benzenedithiols, and their transition metal complexes. Nickel, copper, or cobalt is preferably used as the central metal of the transition metal complex. Compounds represented by the following formula (2) can also be used. Here, R １ are each independently an alkyl group, an alkenyl group, an aryl group, a heterocyclic group, or R ９ CO － , R １０ SO ２－ or R １１ NHCO － R represents a group represented by ９ , R １０ , and R １１ R each independently represents an alkyl group, an alkenyl group, an aryl group, or a heterocyclic group. ２ and R ３ each independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an alkoxy group, or an alkenyloxy group; R ４ ~R ８ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an aryl group, which may be used alone or in combination.

[0071] (Peroxide decomposer) A peroxide decomposer decomposes peroxides generated when a dye undergoes oxidative degradation, stops the autoxidation cycle, and inhibits dye degradation (fading). Phosphorus-based antioxidants and sulfur-based antioxidants can be used as peroxide decomposers.

[0072] Examples of phosphorus-based antioxidants include 2,2'-methylenebis(4,6-di-t-butyl-1-phenyloxy)(2-ethylhexyloxy)phosphorus, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, and 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-t-butyldibenz[d,f][1,3,2]dioxaphosphepine.

[0073] Examples of sulfur-based antioxidants include 2,2-bis({[3-(dodecylthio)propionyl]oxy}methyl)-1,3-propanediyl-bis[3-(dodecylthio)propionate], 2-mercaptobenzimidazole, dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, pentaerythrityl-tetrakis(3-laurylthiopropionate), and 2-mercaptobenzothiazole.

[0074] 2 absorbs ultraviolet rays that deteriorate the pigment contained in the colored layer 3. The ultraviolet absorbing layer 4 can be formed by applying to the substrate 1 and curing a composition for forming an ultraviolet absorbing layer, the composition containing an active energy ray-curable resin, an ultraviolet absorber (UVA), a photopolymerization initiator, and a solvent.

[0075] In the optical laminate 10 shown in FIG. 1, either the substrate 1 or the functional layer 2 may contain an ultraviolet absorber to serve as an ultraviolet absorbing layer.

[0076] In both cases where either the base 1 or the functional layer 2 is used as the ultraviolet absorbing layer, and where a separate ultraviolet absorbing layer 4 is provided, the ultraviolet absorbing layer preferably has an ultraviolet shading rate of 85% or more. Here, the ultraviolet shading rate is a value measured in accordance with JIS L 1925 and is calculated by the following formula: ultraviolet shading rate (%) = 100 - average transmittance (%) of ultraviolet light with a wavelength of 290 to 400 nm.

[0077] The ultraviolet absorber may be a benzophenone-based, benzotriazole-based, triazine-based, oxalic acid anilide-based, or cyanoacrylate-based compound. The ultraviolet absorber is blended to suppress deterioration of the pigment contained in the colored layer 3, and therefore, an ultraviolet absorber that has the ability to absorb light in the wavelength range that contributes to deterioration of the pigment contained in the colored layer 3 is used.

[0078] The compositions for forming each layer may contain other additives such as a leveling agent, an antifoaming agent, an antioxidant, a light stabilizer, a photosensitizer, and a conductive material.

[0079] The overall thickness (total thickness) of the optical laminates 10 and 20 is preferably 35 to 100 μm. The ratio of the thickness of the substrate 1 to the overall thickness of the optical laminates 10 and 20 is preferably 70 to 95%, and more preferably 75 to 90%. When the ratio of the thickness of the substrate 1 to the overall thickness of the optical laminates 10 and 20 is 70% or more, more preferably 75% or more, the flexibility of the optical laminates 10 and 20 can be improved, and when the ratio of the thickness of the substrate 1 to the overall thickness of the optical laminates 10 and 20 is 95% or less, more preferably 90% or less, the functions of the functional layer and the colored layer can be sufficiently obtained.

[0080] As described above, the optical laminates 10 and 20 according to the present invention have an absolute value of the difference in tensile elongation at break before and after lamination of the colored layer 3 that is less than 10% of the tensile elongation at break before the colored layer is formed. In other words, the colored layer 3 easily elongates to follow the bending of the substrate 1, and has high followability to the bending of the substrate 1. Therefore, even when a bending load is applied due to bending, local deformation of the optical laminates 10 and 20 is suppressed, and the occurrence of defects such as cracks is suppressed. Therefore, the optical laminates 10 and 20 according to the present invention can be suitably used as components of flexible displays, etc., and are less likely to develop defects even when bent with a small radius of curvature. Furthermore, the optical laminates 10 and 20 according to the present invention have a colored layer 3 that absorbs light in a specific wavelength range in the visible light region, thereby enabling display devices to have low reflectance and high brightness.

[0081] Examples of specific implementations of the present invention will be described below.

[0082] (Substrate) The following materials were used as the substrate: PET1: polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, O700, substrate thickness 38 μm, UV shielding rate 87.9%) PET2: polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, O700, substrate thickness 50 μm, UV shielding rate 88.5%) PET3: polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, O700, substrate thickness 75 μm, UV shielding rate 89.0%)

[0083] (Hard Coat Layer Forming Composition) A resin material, photopolymerization initiator, and additives were mixed in the ratios shown below, and diluted with methyl isobutyl ketone to a total solids content of 40%, to prepare a hard coat layer forming composition. Active energy ray curable resin Light Acrylate PE-3A, Kyoeisha Chemical Co., Ltd....62 parts by mass SMP-250AP, Kyoeisha Chemical Co., Ltd....33 parts by mass Karenz MT (registered trademark) PE1, Showa Denko K.K....1 part by mass Photopolymerization initiator OMNIRAD (registered trademark) 184, IGM Resin...3.5 parts by mass Leveling agent KY-1203, Shin-Etsu Chemical Co., Ltd....0.5 parts by mass

[0084] (Colored layer forming composition) Colored layer forming compositions 1 to 3 (colored layers 1 to 3) were prepared by mixing the dye, resin material, photopolymerization initiator, solvent, and additives in the proportions shown in Table 1 below. The proportions of each component shown in Table 1 are in mass %. The materials used are as follows:

[0085] (Dye) First coloring material (Dye-1): Pyrromethene cobalt complex dye (maximum absorption wavelength: 493 nm, full width at half maximum: 26 nm) obtained in the following production example. <Production example of Dye-1> Ethyl 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylate (2.5 g) was sealed in a reaction vessel and dissolved in methanol (50 mL), after which 47% hydrobromic acid (45 g) was added and refluxed for 1 hour. The precipitated solid was filtered off to obtain 3,3',5,5'-tetramethyl-4,4'-diethoxycarbonyl-2,2'-dipyrromethene hydrobromide (2.6 g). 3,3',5,5'-Tetramethyl-4,4'-diethoxycarbonyl-2,2'-dipyrromethene hydrobromide (0.6 g) was placed in a reaction vessel, and methanol (5 mL), triethylamine (0.17 g), and cobalt acetate tetrahydrate (0.18 g) were added, followed by refluxing for 2 hours. The precipitated solid was filtered off to obtain Dye-1 (0.42 g). Second coloring material: A mixture of the following Dye-2 and Dye-3 in a mass ratio of 60:40 was used. (Dye-2): Tetraazaporphorin copper complex dye (manufactured by Yamamoto Chemical Industry Co., Ltd., PD-311S, maximum absorption wavelength 586 nm, half width 22 nm) (Dye-3): Tetraazaporphorin copper complex dye (manufactured by Yamada Chemical Industry Co., Ltd., FDG-007, maximum absorption wavelength 595 nm, half width 22 nm) Third coloring material (Dye-4): Phthalocyanine copper complex dye (manufactured by Yamada Chemical Industry Co., Ltd., FDN-002, minimum transmittance wavelength in the range of 400 to 780 nm: 780 nm)

[0086] (Resin Materials) Resin 1: A polymer having a structural unit represented by the following formula (3) (in formula (1), R ａ is CH ３ , R ｂ is CH ３ , X is a single bond, weight average molecular weight: 50,000)

[0087] <Production Example of Resin 1> 2.4 g of 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate (FA-711MM, manufactured by Showa Denko Materials Co., Ltd.), 5.6 g of methyl methacrylate (Kanto Chemical Co., Ltd.), 31 g of cyclohexanone (Kanto Chemical Co., Ltd.), and 0.11 g of 2,2'-azobis(isobutyronitrile) (Fujifilm Wako Pure Chemical Industries, Ltd.) were placed in a reaction vessel and heated with stirring at 70°C for 8 hours under a nitrogen gas atmosphere. The mixture was then heated with stirring at 100°C for 1 hour to obtain a polymer solution. This polymer solution was poured into 400 mL of methanol (Kanto Chemical Co., Ltd.), and the resulting precipitate was filtered and dried to obtain Resin 1, which was copolymerized with 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate and methyl methacrylate in a ratio of 15:85 [mol %].

[0088] By further heating and stirring at 100°C for 1 hour, the initiator 2,2'-azobis(isobutyronitrile) can be completely decomposed, and deterioration of the optical film due to residual initiator can be suppressed. Furthermore, by pouring the polymer solution into methanol, unreacted monomers, polymerization solvent, decomposition products of the initiator, etc. can be removed, and deterioration of the optical film can be suppressed.

[0089] UA-306H: Pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer (manufactured by Kyoeisha Chemical Co., Ltd.) DPHA: Dipentaerythritol hexaacrylate PE3A: Pentaerythritol triacrylate (manufactured by Kyoeisha Chemical Co., Ltd. Light Acrylate PE-3A)

[0090] (Photopolymerization initiator) Omnirad (registered trademark) TPO: 2,4,6-trimethylbenzoyldiphenylphosphine oxide (manufactured by IGM Resins BV).

[0091] (Additives) D1781: Singlet oxygen quencher, bis(dibutyldithiocarbamate)nickel(II) (manufactured by Tokyo Chemical Industry Co., Ltd.) T1477: Singlet oxygen quencher, 3,3,3',3'-tetramethyl-5,5',6,6'-tetrapropoxy-1,1'-spirobiindane (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0092] A hard coat layer-forming composition was applied to the first surface of the substrate shown in Table 2 below, dried, and then irradiated with ultraviolet light to cure the coating, forming a hard coat layer. The coating amount of the hard layer-forming composition was adjusted so that the film thickness after curing would be 9 μm. Next, a colored layer-forming composition shown in Table 2 was applied to the second surface of the substrate, dried, and then irradiated with ultraviolet light to cure the coating, forming a colored layer. The coating amount of the colored layer-forming composition was adjusted so that the film thickness after curing would be 6 μm.

[0093] (Tensile Breaking Elongation) The tensile breaking elongation of the laminate before and after the formation of the colored layer in each example and comparative example was measured using a materials testing machine (STB-1225L, manufactured by A&D Co., Ltd.). Specifically, the laminate before and after the formation of the colored layer was cut into a dumbbell shape No. 5 (compliant with JIS K7127 Type 5) to prepare a sample. The sample prepared in a room adjusted to a temperature of 23°C and a humidity of 50% RH was set in the testing machine so that the distance between chucks was 80 mm, and the sample was pulled at a rate of 50 mm / min, and the tensile breaking elongation in each of the longitudinal and width directions of the film was calculated using the following formula: Tensile breaking elongation (%) = 100 × (L - L ０ ) / L ０ In the above formula, L is the gauge length (mm) at break, and L ０ is the gauge length of the measurement origin (80 mm).

[0094] For each of the Examples and Comparative Examples, measurements were taken five times in the longitudinal and transverse directions of the film before and after the formation of the colored layer, and the arithmetic mean value was used as the evaluation value.

[0095] (Flexibility) A test specimen measuring 80 mm in the longitudinal direction (MD) and 30 mm in the transverse direction (TD) was cut out from the optical laminate of each Example and Comparative Example. The test specimen was set in a bending tester (DLDMLH-FS, manufactured by Yuasa System Co., Ltd.) so that the colored layer was bent outward, and the test specimen was bent 200,000 times along a direction perpendicular to the longitudinal direction with a bending radius (R) of 4 mm, and then the bending resistance (MD) was evaluated. The bending resistance (TD) was evaluated by cutting out a test specimen measuring 30 mm in the longitudinal direction (MD) and 80 mm in the transverse direction (TD), and bending the test specimen 200,000 times along a direction perpendicular to the transverse direction with a bending radius (R) of 4 mm. The test was performed under conditions of 25°C, 50% RH, and a bending speed of 60 times / min. If no defects occurred in the test piece after the bending test with a bending radius (R) of 4 mm, the bending radius (R) was reduced by 1 mm using the same test piece, and the same test was performed up to a bending radius (R) of 2 mm. The bending resistance was evaluated according to the following criteria depending on the bending radius and the presence or absence of defects. ○: No defects occurred even with a bending radius (R) of 2 mm △: No defects occurred with a bending radius (R) of 3 mm, but defects occurred with a bending radius (R) of 2 mm ×: No defects occurred with a bending radius (R) of 4 mm, but defects occurred with a bending radius (R) of 3 mm XX: Defects occurred with a bending radius (R) of 4 mm

[0096] Table 2 shows the layer structures and evaluation results of Examples 1 to 4 and Comparative Examples 1 to 5.

[0097] As shown in Table 2, the absolute value of the difference in tensile elongation at break before and after formation of the colored layer in the optical laminates according to Examples 1 to 4 was less than 10% of the tensile elongation at break before formation of the colored layer in both the MD and TD directions. As a result, as shown in the results of the bending resistance test, the colored layer was easy to stretch and had good conformability to bending of the substrate, and even when a bending resistance test was performed with a bending radius of 2 mm, defects such as cracks did not occur in the colored layer.

[0098] In contrast, in the optical laminates according to Comparative Examples 1 to 5, the absolute value of the difference in tensile breaking elongation before and after the formation of the colored layer in the TD direction or in both the MD and TD directions exceeded 10% of the tensile breaking elongation before the formation of the colored layer, and the results of the bending resistance test in the corresponding directions were inferior to those of the Examples.

[0099] The present invention can be used as a protective film for display devices, and is particularly suitable as a protective film for bendable flexible displays.

[0100] REFERENCE SIGNS LIST 1 substrate 2 functional layer 3 colored layer 4 ultraviolet absorbing layer 8 display panel 10, 20 optical laminate 100, 200 display device

Claims

1. An optical laminate comprising a sheet-like substrate, a functional layer formed on a first surface of the substrate, and a colored layer formed on a second surface of the substrate, the tensile elongation at break measured in accordance with JIS K 7127 (7161) satisfying the following condition in both the longitudinal direction (MD) and the transverse direction (TD): |Lb-La|<|La x 0.1|, where La: tensile elongation at break (%) when the functional layer is formed on the substrate, Lb: tensile elongation at break (%) when the functional layer and the colored layer are formed on the substrate.

2. The optical laminate according to claim 1, wherein the colored layer contains as a pigment at least one of the following: a first coloring material having a maximum absorption wavelength in the range of 470 nm or more and 530 nm or less and a half-width of an absorption spectrum in the range of 15 nm or more and 45 nm or less; a second coloring material having a maximum absorption wavelength in the range of 560 nm or more and 620 nm or less and a half-width of an absorption spectrum in the range of 15 nm or more and 55 nm or less; and a third coloring material having a wavelength of 400 nm or more and 780 nm or less with the lowest transmittance in the wavelength range of 650 nm or more and 780 nm or less; and wherein the optical laminate contains a polymer containing a structural unit represented by the following formula (1): Here, R ａ represents a hydrogen atom, a halogen atom, a carboxyl group, a sulfo group, a cyano group, a hydroxy group, an alkyl group having 10 or less carbon atoms, an alkoxycarbonyl group having 10 or less carbon atoms, an alkylsulfonylaminocarbonyl group having 10 or less carbon atoms, an arylsulfonylaminocarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, an acylaminosulfonyl group having 10 or less carbon atoms, an alkoxy group having 10 or less carbon atoms, an alkylthio group having 10 or less carbon atoms, an aryloxy group having 10 or less carbon atoms, a nitro group, an alkoxycarbonyloxy group, an aryloxycarbonyloxy group, an acyloxy group having 10 or less carbon atoms, an acyl group having 10 or less carbon atoms, a carbamoyl group, a sulfamoyl group, an aryl group having 10 or less carbon atoms, a substituted amino group, a substituted ureido group, a substituted phosphono group, or a heterocyclic group; R ｂ represents a hydrogen atom or an alkyl group having 30 or less carbon atoms, X represents a single bond, an ester group, an aliphatic alkyl chain having 30 or less carbon atoms, an aromatic chain, a polyethylene glycol chain, or a linking group formed by combining these, any of which may contain a spirodioxane ring.

3. The optical laminate according to claim 2, wherein the colored layer further comprises at least one of a singlet oxygen quencher and a peroxide decomposer.

4. The optical laminate according to claim 3, wherein the singlet oxygen quencher comprises any one of dialkyl phosphate, dialkyl dithiocarbamate, benzenedithiol, and transition metal complexes thereof, and a compound represented by the following formula (2): Here, R １ each independently represents an alkyl group, an alkenyl group, an aryl group, a heterocyclic group, or R ９ CO － , R １０ SO ２－ Or R １１ N.H.C.O. － R represents a group represented by ９ , R １０ , and R １１ R each independently represents an alkyl group, an alkenyl group, an aryl group, or a heterocyclic group. ２ and R ３ each independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an alkoxy group, or an alkenyloxy group; R ４ ~R ８ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an aryl group.

5. The optical laminate according to claim 2, wherein the dye comprises one or more compounds selected from the group consisting of compounds having any one of a porphyrin structure, a merocyanine structure, a phthalocyanine structure, an azo structure, a cyanine structure, a squarylium structure, a coumarin structure, a polyene structure, a quinone structure, a tetradiporphyrin structure, a pyrromethene structure, and an indigo structure, and metal complexes thereof.

6. The optical laminate according to claim 1, wherein the substrate or the functional layer is an ultraviolet absorbing layer having an ultraviolet shielding rate of 85% or more in accordance with JIS L 1925.

7. The optical laminate according to claim 1, further comprising an ultraviolet absorbing layer between the substrate and the colored layer, the ultraviolet absorbing layer having an ultraviolet shielding rate of 85% or more in accordance with JIS L 1925.

8. The optical laminate according to claim 1, wherein the substrate is made of any one of polyethylene terephthalate, polyethylene naphthalate, and polyimide.

9. The optical laminate according to claim 1, wherein the functional layer comprises any one of a hard coat layer, an antireflection layer including a high refractive index layer or a low reflectance layer, and an antiglare layer.

10. The optical laminate according to claim 1, wherein the ratio of the thickness of the substrate to the total thickness of the optical laminate is 70% or more and 95% or less.

11. The optical laminate according to claim 1, wherein the colored layer is a cured film of a composition containing an active energy ray curable resin, the dye, and a photopolymerization initiator, and the active energy ray curable resin contains (meth)acrylate or urethane (meth)acrylate.

12. The optical laminate according to claim 11, wherein the content of the active energy ray-curable resin in the composition is 50 to 70 mass % of the total solid content.

13. The optical laminate according to claim 12, wherein the ratio of the thickness of the substrate to the total thickness of the optical laminate is 75% or more and 90% or less, and the content of the active energy ray-curable resin in the composition is 55 to 65% by mass of the total solid content.

14. A display device comprising the optical laminate of claim 1.

15. A foldable display device comprising the optical laminate of claim 14, wherein the optical laminate is arranged in the order of the functional layer, the base material, and the colored layer from the inside in the folding direction of the display device.

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