Optical laminate and display device using the same

Abstract

To provide an optical laminate which is suitably usable as a component of a flexible display, etc., and with which defects hardly occur even when bent with a small radius of curvature, and with which it is possible to lower the reflectivity and heighten the luminance of a display device, and a display device using the optical laminate.SOLUTION: Provided is an optical laminate comprising a sheet-like substrate, a functional layer formed on one surface of the substrate, and a coloring layer formed on the second surface of the substrate, with its tensile fracture elongation measured in conformity with JIS K 7127(7161) satisfying the condition below in both longer direction (MD) and width direction (TD). |Lb-La|<|La×0.1|, where La represents a tensile fracture elongation (%) while functional layer is formed on substrate, Lb represents tensile fracture elongation (%) while functional layer and colored layer are formed on substrate.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In the display surface of a self-emitting display device such as an organic EL display device, metal electrodes and wirings are formed. Since these metal electrodes and wirings reflect light incident from the outside (i.e., external light), it is easy to cause a decrease in display quality such as a decrease in contrast. In order to improve the display quality, a configuration in which a polarizing plate and a retardation plate (circular polarizing plate) are provided has been proposed. However, when the light emitted from the display device passes through the circular polarizing plate and is emitted to the outside, most of the light is lost, which easily leads to an increase in power consumption and a decrease in the element life.

[0003] As a display device different from the above-described configuration, for example, Patent Document 1 describes a configuration including an optical filter containing a dye that selectively absorbs a predetermined wavelength band. Since the optical filter described in Patent Document 1 selectively absorbs light in a wavelength band that particularly reduces color purity among the light emitted from the display device, the loss of light necessary for the display of the three primary colors can be suppressed, and the visibility of the display image can be improved.

[0004] In recent years, the adoption of flexible displays has been progressing, and in addition to the optical characteristics and durability conventionally required for the members forming the display device, there is a tendency to require bending resistance. An optical filter that can be dealt with by additional formation on a functional layer has high affinity for a flexible display compared to a circular polarizing plate that is difficult to be thinned due to its own thickness.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] A hard coat film having surface protection characteristics and flex resistance is used on the surface of the flexible display. When an optical filter layer (coloring layer) that selectively absorbs a predetermined wavelength band is applied to such a hard coat film, considering reliability such as light resistance and heat resistance, when constructing a flexible display, in order from the inside of the display, for example, the layer structure is an optical filter layer / base material / functional layer, or an optical filter layer / functional layer / base material / functional layer. Thus, the optical filter layer is provided.

[0007] In the case of a conventional optical laminate, when it is curved so that the radius of curvature gradually becomes smaller, even at a stage with a relatively large radius of curvature, fine cracks are likely to occur in the coloring layer on the outer side of the bent portion. Considering application to a display device that can be curved or folded, it is required that the optical laminate is less likely to cause defects even when curved with 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, is less likely to cause defects even when curved with a small radius of curvature, and can achieve a lower reflectance and higher brightness of the display device, and a display device using the same.

Means for Solving the Problems

[0009] The optical laminate according to the present invention includes a sheet-like base material, a functional layer formed on the first surface side of the base material, and a coloring layer formed on the second surface side of the base material, and the tensile fracture elongation 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| Here, La: Tensile fracture elongation amount (%) in the state where the functional layer is formed on the base material Lb: Tensile fracture elongation amount (%) in the state where the functional layer and the coloring layer are formed on the base material That is.

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

Advantages of the Invention

[0011] According to the present invention, it can be suitably used as a component such as a flexible display, and even when curved with a small radius of curvature, it is less likely to cause defects, and an optical laminate capable of reducing the reflectance and increasing the brightness of the display device, and a display device using the same can be provided.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0013] FIG. 1 and FIG. 2 are cross-sectional views showing the schematic configurations of the display devices according to the first embodiment and the second embodiment, respectively. The upper sides in FIGS. 1 and 2 correspond to the observation sides when observing the display images of the display devices. Further, when the display device is a flexible display, the upper surfaces in FIGS. 1 and 2 are the inner surfaces 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 wirings, etc. are provided in the display surface. The optical laminate 10 includes a base material 1, a functional layer 2 laminated on the first surface side (observation side) of the base material 1, and a coloring layer 3 laminated on the second surface side (display panel 8 side) of the base material 1. The optical laminate 10 is bonded to the display panel 8 such that the coloring layer 3 faces the display panel 8 side.

[0015] The display device 200 shown in Fig. 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 base material 1, a functional layer 2 laminated on the first surface side (observation side) of the base material 1, and an ultraviolet absorption layer 4 and a coloring layer 3 laminated on the second surface side (display panel 8 side) of the base material 1. The optical laminate 20 is bonded to the display panel 8 such that the coloring layer 3 faces the display panel 8 side.

[0016] A part of the external light incident on the display panel 8 is reflected by the metal electrodes and metal wirings of the display panel 8. Since the light reflected inside the display devices 100 and 200 causes deterioration in the contrast and visibility of the display image on the display panel 8, conventionally, a circular polarizing plate has been used to reduce the reflected light on the surface of the display panel 8. Since 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, a part of the incident external light is absorbed. A part of the remaining external light that is not absorbed by the coloring layer 3 is reflected by the display panel 8, but a part of the reflected light is absorbed by the coloring layer 3. As a result, the internal reflectance of the external light is significantly reduced. Further, by making the absorption wavelength range of the dye contained in the coloring layer 3 not overlap with the peak wavelength of the light emitted from the display panel 8, it is possible to suppress a decrease in the luminance of the three primary colors emitted from the display panel 8 as compared with the case where a circular polarizing plate is provided, and it is possible to improve the visibility of the display image on the display panel 8.

[0017] In addition, the tensile fracture elongation amounts of the optical laminates 10 and 20 according to the present invention satisfy the following conditions in both the longitudinal direction (MD) and the width direction (TD). The tensile fracture elongation amount is a value measured in accordance with JIS K 7127 (7161). |Lb - La| < |La × 0.1| Here, La: Tensile fracture elongation amount (before forming the coloring layer) in a state where the functional layer is formed on the base material Lb: Tensile fracture elongation amount (after forming the coloring layer) in a state where the functional layer and the coloring layer are formed on the base material is.

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

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

[0020] (Base material) The base material 1 is a film that serves as the base of the optical laminates 10 and 20. As the base material 1, a material made of a material excellent in the transparency of visible light and the mechanical strength required for a flexible display is selected. Examples of the material for forming the base material 1 include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyimide (PI). The thickness of the base material 1 is preferably 10 to 100 μm, and more preferably 20 to 60 μm. When the thickness of the base material 1 is below the upper limit value, it can be made lighter, which is advantageous for thinning the display device. When the thickness of the base material 1 is above the lower limit value, 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 characteristics of the optical laminates 10 and 20, and may include one or more of a hard coat layer, an antireflection layer including a high refractive index layer or a low reflectivity layer, and an antiglare 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 composition for forming a hard coat layer containing an active energy ray curable resin, a photoinitiator, 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 hardness of the hard coat layer may be insufficient. If the thickness of the hard coat layer 22 exceeds 10 μm, it 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 according to the surface hardness required for the optical laminate and the overall thickness.

[0023] The active energy ray curable resin is a resin that polymerizes and cures by irradiation with active energy rays such as ultraviolet rays and electron beams. For example, monofunctional, bifunctional, or trifunctional or higher (meth)acrylate monomers 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. It 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, acryloylmorpholine, N-vinylpyrrolidone, tetrahydrofurfuryl acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isobornyl (meth)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-modified phenoxy (meth)acrylate, nonylphenol (meth)acrylate, ethylene oxide-modified nonylphenol (meth)acrylate, propylene oxide-modified nonylphenol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxypolythylene 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)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,Examples of adamantyl acrylate derivatives mono(meth)acrylates such as adamantyl acrylate having a monovalent mono(meth)acrylate derived from adamantanediol can be mentioned.

[0025] Examples of bifunctional (meth)acrylate compounds include 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, hydroxypivalic acid neopentyl glycol di(meth)acrylate, and other di(meth)acrylates.

[0026] Examples of (meth)acrylate compounds having three or more functional groups 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; trifunctional (meth)acrylate compounds such as pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, and ditrimethylolpropane tri(meth)acrylate; 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 part of these (meth)acrylates is substituted with an alkyl group or ε-caprolactone.

[0027] Also, urethane (meth)acrylate can be used as the active energy ray-curable resin. 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 prepolymer.

[0028] Examples of urethane (meth)acrylate 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, dipentaerythritol pentaacrylate isophorone diisocyanate urethane prepolymer, and the like.

[0029] The above-mentioned active energy ray-curable resin may be used alone or in combination of two or more. Also, in the above-mentioned active energy ray-curable resin and the composition for forming a hard coat layer, it may be a monomer or a partially polymerized oligomer.

[0030] As the photoinitiator used in the composition for forming a hard coat layer, for example, 2,2-ethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, dibenzoyl, benzoin, benzoin methyl ether, benzoin ethyl ether, p-chlorobenzophenone, p-methoxybenzophenone, Michler's ketone, acetophenone, 2-chlorothioxanthone, etc. can be used. One of these may be used alone or two or more may be used in combination.

[0031] In addition, examples of the solvent used in the composition for forming the hard coat layer 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] In addition, the composition for forming the hard coat layer may contain metal oxide fine particles for the purpose of adjusting the refractive index and imparting hardness. Examples of the 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] In addition, the composition for forming the hard coat layer may contain any one of silicon oxide, a fluorine-containing silane compound, fluoroalkylsilazane, fluoroalkylsilane, a fluorine-containing silicon-based compound, and a perfluoropolyether group-containing silane coupling agent to impart water repellency and / or oil repellency and enhance antifouling properties.

[0034] (Antireflection layer) The antireflection layer is a layer that suppresses external light reflection 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 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. As the high refractive index fine particles, 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 can be used. As the active energy ray curable resin, photopolymerization initiator, and solvent, the compounds exemplified in the hard coat layer can be used.

[0036] The thickness of the high refractive index layer is not particularly limited, but is preferably 10 to 300 nm. Also, 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. In the composition for forming a low refractive index layer, fine particles such as LiF, MgF, 3NaF·AlF3, AlF, and silica fine particles may be blended for refractive index adjustment. Also, as the silica fine particles, those having voids inside the particles such as porous silica fine particles and hollow silica fine particles are effective for reducing the refractive index of the low refractive index layer. As the active energy ray curable resin, photopolymerization initiator, and solvent, the compounds exemplified in the hard coat layer can be used.

[0038] The thickness of the low refractive index layer is not particularly limited, but is preferably 40 to 300 nm. Also, 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 one of silicon oxide, a fluorine-containing silane compound, a fluoroalkylsilazane, a fluoroalkylsilane, a fluorine-containing silicon-based compound, and a perfluoropolyether group-containing silane coupling agent. These materials can enhance the antifouling property by imparting water repellency and / or oil repellency to the low refractive index layer.

[0040] Alternatively, an 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 from the substrate 1. The medium refractive index layer only needs to 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 can be formed by applying and curing a composition for forming a medium refractive index layer in which metal oxide fine particles described in the high refractive index layer are added to the active energy ray curable resin, photoinitiator, and solvent described in the hard coat layer to adjust the refractive index on the substrate 1.

[0041] (Antiglare layer) The antiglare layer is a layer that has fine irregularities on its surface and reduces the reflection of external light by scattering the external light with these irregularities. The antiglare layer can be formed by applying and curing a composition for forming an antiglare layer in which organic fine particles and / or inorganic fine particles are added to the active energy ray curable resin, photoinitiator, and solvent as necessary. As the active energy ray curable resin, photoinitiator, and solvent, the compounds exemplified in the hard coat layer can be used.

[0042] The film 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 the antiglare layer are materials that mainly form fine irregularities on the surface of the antiglare layer and impart a function of diffusing external light. As the organic fine particles, resin particles made of a light-transmitting resin material such as acrylic resin, polystyrene resin, styrene-(meth)acrylate copolymer, polyethylene resin, epoxy resin, silicone resin, polyvinylidene fluoride, and polyfluoroethylene-based resin can be used. In order to adjust the refractive index and the dispersibility of the resin particles, two or more types of resin particles having different materials (refractive indices) may be mixed and used.

[0044] The inorganic fine particles used in the composition for forming the antiglare layer are mainly materials for adjusting the sedimentation and aggregation of the organic fine particles in the antiglare layer. 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 reactive functional groups such as (meth)acryloyl groups, 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. As the mineral fine particles, for example, mica, synthetic mica, vermiculite, montmorillonite, iron montmorillonite, bentonite, beidellite, saponite, hectorite, stevensite, nontronite, magadiite, illite, kanemite, layered titanic acid, smectite, synthetic smectite, etc. can be used. The mineral fine particles may be either natural products or synthetic products (including substituents and derivatives), or a mixture of both may be used. Among the mineral fine particles, layered organic clay is more preferable. The layered organic clay refers to a material in which organic onium ions are introduced between the layers of the swellable clay. The organic onium ions are not limited as long as they can be organically modified by utilizing the cation exchangeability of the swellable clay. When using layered organic clay minerals as the mineral fine particles, the above-mentioned synthetic smectite can be preferably used. The synthetic smectite has a function of increasing the viscosity of the coating liquid for forming the antiglare layer, suppressing the sedimentation of the resin particles and the inorganic fine particles, and adjusting the uneven shape of the surface of the optical functional layer.

[0045] The composition for forming the antiglare layer may contain any one of silicon oxide, fluorine-containing silane compound, fluoroalkylsilazane, fluoroalkylsilane, fluorine-containing silicon-based compound, and perfluoropolyether group-containing silane coupling agent. These materials can enhance the antifouling property by imparting water repellency and / or oil repellency to the antiglare layer.

[0046] (Coloring layer) The coloring layer 3 is a layer for reducing the light emitted from the display panel 8 and transmitted through the optical laminates 10 and 20, and the reflected light that is reflected by the metal electrode member or the reflecting member of the display panel 10 and re-emitted, and contains a dye for selectively absorbing a specific wavelength band of visible light. The coloring layer can be formed by applying and curing a composition for forming a coloring layer containing an active energy ray curable resin, a dye, a photoinitiator, and a solvent, and optionally additives described later. As the active energy ray curable resin, photoinitiator, and solvent used for forming the coloring layer 3, the compounds exemplified in the hard coat layer can be used.

[0047] The coloring layer 3 contains, as a dye, one or more of the color materials shown below. By using those having the following absorption characteristics, the coloring layer 3 can absorb the visible light in the wavelength range where the relative emission intensity is low among the visible light emitted from the display panel 8. (1) A first color material having a maximum absorption wavelength in the range of 470 nm or more and 530 nm or less, and a half-value width of the absorption spectrum in the range of 15 nm or more and 45 nm or less (2) A second color material having a maximum absorption wavelength in the range of 560 nm or more and 620 nm or less, and a half-value width of the absorption spectrum in the range of 15 nm or more and 55 nm or less (3) A third color material having the wavelength with the lowest transmittance in the wavelength range of 400 nm or more and 780 nm or less in the range of 650 nm or more and 780 nm or less

[0048] The thickness of the coloring layer 3 is not particularly limited, but is preferably 0.5 to 10 μm. When the thickness of the coloring layer 3 is less than 0.5 μm, the dye concentration contained in the coloring layer 3 may not be sufficient, and the light absorption may be insufficient. When the thickness of the coloring layer 3 is less than 0.5 μm, if the dye concentration is increased to ensure light absorption, it is not preferable because abnormalities occur in the appearance. On the other hand, when the thickness of the coloring layer 3 exceeds 10 μm, it is not preferable because it is disadvantageous for thinning the optical laminates 10 and 20.

[0049] As the dye to be incorporated into the coloring layer 3, dyes, pigments, nano metals, etc. can be used, but it is preferably at least one compound 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 tetrapyridylporphyrin structure, a pyromethene structure, and an indigo structure, and metal complexes thereof. In particular, metal complexes having a porphyrin structure, a pyromethene structure, or a phthalocyanine structure, and compounds having a squarylium structure are more preferred because of their excellent reliability. These compounds may be contained alone or in combination of two or more. Further, depending on the color adjustment and the intended optical properties, a dye having a wide half-value width of the absorption spectrum may be used in combination.

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

Chemical formula

[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, and R brepresents a hydrogen atom or an alkyl group having 30 or fewer carbon atoms, X represents a single bond, an ester group, an aliphatic alkyl chain having 30 or fewer carbon atoms, an aromatic chain, a polyethylene glycol chain, or a linking group formed by combining these, and any of them may contain a spirodioxane ring.

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

[0053] In addition, the resin having an amine structure with radical scavenging ability is mainly composed of a copolymer of a structural unit represented by the formula (1) and a copolymerizable component having any of the repeating units described below (the component with the largest mass percentage among the components). By being a copolymer, the compatibility with other components can be controlled.

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

[0055] Examples of the (meth)acrylate-based repeating unit include repeating units derived from (meth)acrylate-based monomers having a linear or branched alkyl group in the side chain, repeating units derived from (meth)acrylate-based monomers having a hydroxy group in the side chain, and the like.

[0056] Examples of the repeating unit derived from the (meth)acrylate monomer having the above linear or branched alkyl group in the side chain include monomer-derived components such as 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, isooctyl (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 these, (meth)acrylate repeating units having a linear or branched alkyl group with 1 to 4 carbon atoms in the side chain can be preferably used.

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

[0058] Examples of the olefin-based repeating unit include olefin-based monomer-derived components such as ethylene, propylene, isoprene, and butadiene. 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 and vinylidene chloride. These may be used alone or in combination of two or more.

[0060] Examples of the styrene-based repeating unit 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 the vinyl acetate-based repeating unit include ester compounds of saturated carboxylic acids such as vinyl acetate and vinyl propionate and vinyl alcohol. These may be used alone or in combination of two or more. Examples of the vinyl alcohol-based repeating unit include vinyl alcohol, which may have a 1,2-glycol bond in the side chain.

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

[0062] For the polymerization method for obtaining the copolymer, radical polymerization can be used. Radical polymerization is preferable in that industrial production is easy. Radical polymerization may be a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a suspension polymerization method, or the like. It is preferable to use the solution polymerization method for radical polymerization. By using the solution polymerization method, the control of the molecular weight in the copolymer is easy.

[0063] In radical polymerization, after diluting the above-described monomer with a polymerization solvent, a polymerization initiator may be added to polymerize the monomer.

[0064] The polymerization solvent may be, for example, an ester solvent, an alcohol ether solvent, a ketone solvent, an aromatic solvent, an amide solvent, an alcohol solvent, etc. The ester solvent may be, for example, methyl acetate, ethyl acetate, n-butyl acetate, isobutyl acetate, t-butyl acetate, methyl lactate, ethyl lactate, etc. The alcohol ether solvent may be, for example, 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, 3-methoxy-3-methyl-1-butanol, etc. The ketone solvent may be, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc. The aromatic solvent may be, for example, benzene, toluene, xylene, etc. The amide solvent may be, for example, formamide, dimethylformamide, etc. 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. In addition, in the above-mentioned polymerization solvent, one kind may be used alone, or two or more kinds may be mixed and used.

[0065] The radical polymerization initiator may be, for example, a peroxide and 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 captures radicals during the oxidative degradation of the dye, functions to suppress auto-oxidation, and suppresses dye degradation (fading). As an amine structure having radical scavenging ability, when it is a hindered amine structure with a molecular weight of 2000 or more, many molecules remain in the colored layer, and a sufficient fading suppression effect can be obtained, which is preferable. In addition, flexibility is imparted to the coating film, and when bending stress is applied by bending, local deformation is suppressed and defects such as cracks are suppressed, which is preferable.

[0067] In addition, as the active energy ray curable resin used for forming the colored layer 3, monofunctional, bifunctional or trifunctional or higher (meth)acrylate monomers, urethane (meth)acrylate, etc. can be used.

[0068] The content of the active energy ray curable resin is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, based on the total mass other than the solvent of the composition for forming the colored layer. The content of the structural unit represented by formula (1) is preferably 1 to 95 mol%, more preferably 10 to 90 mol%, based on the total molar amount of the monomers constituting the active energy ray curable resin. When the content is at least the above lower limit value, the fading suppression effect can be further enhanced. When the content is at most the above upper limit value, the ease of stretching during bending of the colored layer 3 can be improved.

[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 contains any of these, further deterioration of the dye can be suppressed and the light absorption performance by the colored layer 3 can be maintained.

[0070] (Singlet oxygen quencher) The singlet oxygen quencher has the function of inactivating highly reactive singlet oxygen, which has the property of easily oxidatively degrading (fading) the dye, and suppressing the oxidative degradation (fading) of the dye. Examples of the singlet oxygen quencher include transition metal complexes, dyes, amines, phenols, and sulfides. Particularly preferred materials include dialkyl phosphates, dialkyldithiocarbamates, benzenedithiol, and their transition metal complexes. Nickel, copper, or cobalt is preferably used as the central metal of the transition metal complex. In addition, the compound represented by the following formula (2) can also be preferably used. [Chemical formula] Here, R 1 each independently represents an alkyl group, an alkenyl group, an aryl group, a heterocyclic group, or a group represented by R 9 CO - , R 10 SO 2- or R 11 NHCO - . R 9 , R 10 , and R 11 each independently represents an alkyl group, an alkenyl group, an aryl group, or a heterocyclic group. R 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 to R 8 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an aryl group. These can be used individually or in combination.

[0071] (Peroxide decomposer) The peroxide decomposer has the function of decomposing the peroxide generated when the dye is oxidatively degraded, stopping the auto-oxidation cycle, and suppressing the dye degradation (fading). As the peroxide decomposer, phosphorus-based antioxidants and sulfur-based antioxidants can be used.

[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), 2-mercaptobenzothiazole, and the like.

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

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

[0076] In either the case where either the base 1 or the functional layer 2 is used as the ultraviolet absorbing layer, or the case where a separate ultraviolet absorbing layer 4 is provided, the ultraviolet shielding rate of the ultraviolet absorbing layer is preferably 85% or more. Here, the ultraviolet shielding rate is a value measured in accordance with JIS L 1925 and is calculated by the following formula. Ultraviolet ray shielding rate (%) = 100 - Average transmittance (%) of ultraviolet rays with wavelengths from 290 to 400 nm

[0077] As the ultraviolet ray absorber, benzophenone-based, benzotriazole-based, triazine-based, oxalic acid anilide-based, and cyanoacrylate-based compounds can be used. Since the ultraviolet ray absorber is blended to suppress the deterioration of the dye contained in the colored layer 3, an absorber having light absorption properties in the wavelength range that contributes to the deterioration of the dye contained in the colored layer 3 among the ultraviolet ray regions is used.

[0078] In addition, leveling agents, defoaming agents, antioxidants, light stabilizers, photosensitizers, conductive materials, etc. may be added as other additives to the composition for forming each layer.

[0079] As described above, in the optical laminates 10 and 20 according to the present invention, the absolute value of the difference in the tensile fracture elongation amount before and after the lamination of the colored layer 3 is less than 10% of the tensile fracture elongation amount before the formation of the colored layer. That is, the colored layer 3 easily stretches following the bending of the base material 1 and has high followability with respect to the bending of the base material 1. Therefore, even when a bending load is applied by 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 constituent members of a flexible display or the like, and defects are less likely to occur even when bent with a small radius of curvature. Further, the high-value laminates 10 and 20 according to the present invention can achieve a lower reflectance and higher brightness of the display device by having the colored layer 3 that absorbs light in a specific wavelength range in the visible light region.

Example

[0080] Hereinafter, examples of specifically implementing the present invention will be described.

[0081] (Base material) The following materials were used as the base material. ·PET1: Polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, O700, base material thickness 38 μm, ultraviolet ray shielding rate 87.9%) ·PET2: Polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, O700, base material thickness 50 μm, UV shielding rate 88.5%) ·PET3: Polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, O700, base material thickness 75 μm, UV shielding rate 89.0%)

[0082] (Composition for forming hard coat layer) The resin material, photoinitiator, and additive were mixed at the ratios shown below, and diluted with methyl isobutyl ketone so that the total solid content became 40%, thereby adjusting the composition for forming a hard coat layer. · Actinic energy ray curable resin Light acrylate PE-3A, manufactured by Kyoeisha Chemical Co., Ltd... 62 parts by mass SMP-250AP, manufactured by Kyoeisha Chemical Co., Ltd... 33 parts by mass Karex MT (registered trademark) PE1, manufactured by Showa Denko K.K... 1 part by mass · Photoinitiator OMNIRAD (registered trademark) 184, manufactured by IGM RESIN... 3.5 parts by mass · Levelling agent KY-1203, manufactured by Shin-Etsu Chemical Co., Ltd... 0.5 part by mass

[0083] (Composition for forming colored layer) The dye, resin material, photoinitiator, solvent, and additive were mixed at the ratios shown in Table 1 below to adjust the colored layer forming compositions 1 to 3 (colored layers 1 to 3). The ratios of the respective components shown in Table 1 are in mass%. The materials used are as follows.

Table 1

[0084] (Dye) · First colorant (Dye-1): Pyromethene cobalt complex dye obtained in the following production example (absorption maximum wavelength 493 nm, half-value width 26 nm). <Production example of Dye-1> Ethyl 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylate (2.5 g) was sealed in a reaction vessel, dissolved in methanol (50 mL), and then 47% hydrobromic acid (45 g) was added, followed by refluxing for 1 hour. By filtering off the precipitated solid, hydrobromide of 3,3’,5,5’-tetramethyl-4,4’-di-ethoxycarbonyl-2,2’-dipyrromethene (2.6 g) was obtained. Hydrobromide of 3,3’,5,5’-tetramethyl-4,4’-di-ethoxycarbonyl-2,2’-dipyrromethene (0.6 g) was sealed in a reaction vessel, and methanol (5 mL), triethylamine (0.17 g), and cobalt(II) acetate tetrahydrate (0.18 g) were added, followed by refluxing for 2 hours. By filtering off the precipitated solid, Dye-1 (0.42 g) was obtained. · Second colorant: A mixture of the following Dye-2 and Dye-3 in a mass ratio of 60:40 was used. (Dye-2): Tetraazaporphyrin copper complex dye (manufactured by Yamamoto Kasei Co., Ltd., PD-311S, maximum absorption wavelength 586 nm, half-value width 22 nm) (Dye-3): Tetraazaporphyrin copper complex dye (manufactured by Yamada Chemical Industry Co., Ltd., FDG-007, maximum absorption wavelength 595 nm, half-value width 22 nm) · Third colorant (Dye-4): Copper phthalocyanine complex dye (manufactured by Yamada Chemical Industry Co., Ltd., FDN-002, minimum transmittance wavelength at 400 - 780 nm: 780 nm)

[0085] (Resin material) · Resin 1: A polymer represented by the following formula (3) (in formula (1), R a is CH3, R b is CH3, X is a single bond, weight average molecular weight: 50000)

Chemical formula

[0086] <Manufacturing example of Resin 1> 2.4 g of 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate (manufactured by Showa Denko Materials Co., Ltd., FA-711MM), 5.6 g of methyl methacrylate (manufactured by Kanto Chemical Co., Inc.), 31 g of cyclohexanone (manufactured by Kanto Chemical Co., Inc.), and 0.11 g of 2,2'-azobis(isobutyronitrile) (manufactured by Fujifilm Wako Pure Chemical Corporation) were placed in a reaction vessel and heated with stirring at 70°C for 8 hours under a nitrogen gas atmosphere. Thereafter, the mixture was heated with stirring at 100°C for 1 hour to obtain a polymer solution. The precipitate formed by pouring this polymer solution into 400 mL of methanol (manufactured by Kanto Chemical Co., Inc.) was filtered and dried to obtain Resin 1 copolymerized at 15:85 [mol%] of 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate:methyl methacrylate.

[0087] By performing additional heating and stirring at 100°C for 1 hour, 2,2'-azobis(is obutyronitrile), which is an initiator, can be completely decomposed, and deterioration of the optical film due to the residual initiator can be suppressed. Further, by pouring the polymer solution into methanol, unreacted monomers, polymerization solvents, decomposition products of the initiator, etc. can be removed, and deterioration of the optical film can be suppressed.

[0088] · 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)

[0089] (Photoinitiator) · Omnirad (registered trademark) TPO: 2,4,6-Trimethylbenzoyl diphenylphosphine oxide (manufactured by IGM Resins B.V.).

[0090] (Additive) ·D1781: Singlet oxygen quencher, nickel(II) bis(dibutyldithiocarbamate) (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.)

[0091] After applying the composition for forming a hard coat layer on the first surface of the base material shown in Table 2 below and drying it, ultraviolet rays were irradiated to cure the coating film to form a hard coat layer. The coating amount of the composition for forming a hard layer was adjusted so that the film thickness after curing would be 9 μm. Next, after applying the composition for forming a colored layer shown in Table 2 on the second surface of the base material and drying it, ultraviolet rays were irradiated to cure the coating film to form a colored layer. The coating amount of the composition for forming a colored layer was adjusted so that the film thickness after curing would be 6 μm.

[0092] (Tensile elongation at break) The tensile elongation at break of the laminate before and after forming the colored layer according to each example and each comparative example was measured using a material testing machine (manufactured by A&D Company, Ltd., STB-1225L). Specifically, the laminate before and after forming the colored layer was cut into a dumbbell shape No. 5 (conforming to JIS K7127 Type 5) to prepare samples. The samples prepared in a room adjusted to a temperature of 23°C and a humidity of 50% RH were set in the testing machine so that the distance between chucks would be 80 mm, and then pulled at a speed of 50 mm / min. The tensile elongation at break in the longitudinal and width directions of the film was obtained by the following formula. Tensile elongation at break (%) = 100×(L - L0) / L0 In the above formula, L is the distance between the gauge points at the time of break (mm), and L0 is the distance between the gauge points at the measurement origin (80 mm).

[0093] For each of the examples and comparative examples before and after forming the colored layer, measurements were taken 5 times each in the longitudinal and width directions of the film, and the arithmetic mean value was used as the evaluation value.

[0094] (Flexural resistance) Test pieces were cut out from the optical laminates of each example and each comparative example with a length of 80 mm in the machine direction (MD) and a width of 30 mm in the transverse direction (TD). The test pieces were set in a bending tester (manufactured by Yuasa System Devices Co., Ltd., DLDMLH-FS) so that the colored layer was on the outer bend, and the test pieces were bent 200,000 times with a bending radius (R) of 4 mm along the direction perpendicular to the longitudinal direction, and then the bending resistance (MD) was evaluated. For the bending resistance (TD), test pieces were cut out with a length of 30 mm in the machine direction (MD) and a width of 80 mm in the transverse direction (TD), and the test pieces were bent 200,000 times with a bending radius (R) of 4 mm along the direction perpendicular to the transverse direction, and then the bending resistance (TD) was evaluated. The test was conducted under the conditions of 25 °C, 50% RH, and a bending speed of 60 times / min. If no defects occurred in the test pieces after the bending test with a bending radius (R) of 4 mm, the bending radius (R) was reduced by 1 mm with the same test pieces, and the same test was conducted until the bending radius (R) reached 2 mm. According to the bending radius and the presence or absence of defects, the bending resistance was evaluated according to the following criteria. ○: No defects occurred even at a bending radius (R) of 2 mm △: No defects occurred at a bending radius (R) of 3 mm, but defects occurred at a bending radius (R) of 2 mm ×: No defects occurred at a bending radius (R) of 4 mm, but defects occurred at a bending radius (R) of 3 mm ××: Defects occurred at a bending radius (R) of 4 mm

[0095] Table 2 shows the layer configurations and evaluation results of Examples 1 to 4 and Comparative Examples 1 to 5.

Table 2

[0096] As shown in Table 2, for the optical laminates according to Examples 1 to 4, the absolute value of the difference in the elongation at break before and after the formation of the colored layer was less than 10% of the elongation at break before the formation of the colored layer in both the MD direction and the TD direction. As a result, as shown in the results of the bending resistance test, the colored layer was easy to stretch, and the followability of the colored layer to the bending of the substrate was good. Even when the bending resistance test was conducted at a bending radius of 2 mm, no defects such as cracks occurred in the colored layer.

[0097] On the other hand, in the optical laminate according to Comparative Examples 1 to 5, in the TD direction, or in both the MD direction and the TD direction, the absolute value of the difference in the tensile elongation at break before and after the formation of the colored layer exceeds 10% of the tensile elongation at break before the formation of the colored layer, and the result of the bending resistance test in the corresponding direction was inferior to that of the Examples.

Industrial Applicability

[0098] The present invention can be used as a protective film for a display device, and is particularly suitable as a protective film for a foldable flexible display.

Explanation of Signs

[0099] 1 Substrate 2 Functional layer 3 Colored layer 4 Ultraviolet absorption layer 8 Display panel 10, 20 Optical laminate 100, 200 Display device

Claims

1. A sheet-like substrate, a functional layer formed on the first surface side of the substrate, and a colored layer formed on the second surface side of the substrate, An optical laminate in which the tensile fracture elongation 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| Here, La: Tensile fracture elongation (%) in the state where the functional layer is formed on the substrate Lb: Tensile fracture elongation (%) in the state where the functional layer and the colored layer are formed on the substrate is.

2. The colored layer contains, as a pigment, a first colorant having a maximum absorption wavelength in the range of 470 nm or more and 530 nm or less and a half-value width of the absorption spectrum in the range of 15 nm or more and 45 nm or less, a second colorant having a maximum absorption wavelength in the range of 560 nm or more and 620 nm or less and a half-value width of the absorption spectrum in the range of 15 nm or more and 55 nm or less, and at least one of a third colorant having a wavelength with the lowest transmittance in the wavelength range of 400 nm or more and 780 nm or less in the range of 650 nm or more and 780 nm or less, The optical laminate according to claim 1, comprising a polymer containing a structural unit represented by the following formula (1). 【Chemical 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, and any of them may contain a spirodioxane ring.

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

4. The optical laminate according to claim 3, wherein the singlet oxygen quencher contains any one of dialkyl phosphate, dialkyldithiocarbamate, benzenedithiol and their transition metal complexes, and a compound represented by the following formula (2). [Chemical 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 NHCO － and the groups represented by R ９ R １０ and R １１ each independently represent an alkyl group, an alkenyl group, an aryl group or a heterocyclic group. R ２ and R ３ each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an alkoxy group or an alkenyloxy group, and R ４ to R ８ each independently represent a hydrogen atom, an alkyl group, an alkenyl group or an aryl group.

5. The optical laminate according to claim 2, wherein the pigment contains 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 tetraporphyrin structure, a pyromethene structure and an indigo structure and their metal complexes.

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

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

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

9. The optical laminate according to claim 1, wherein the functional layer includes 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. A display device comprising the optical laminate of claim 1.

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