Optical thin films, display devices, and components for forming color layers

Abstract

An optical thin film comprises: a substrate having an ultraviolet (UV) shielding rate of 85% or more according to JIS L 1925; an optical functional layer formed on a first side of the substrate; and a coloring layer formed on a second side of the substrate; wherein the color difference ΔE*ab of the optical thin film before and after a lightfastness test is 5 or less. The pigment contained in the coloring layer comprises at least one of the following colorants: a first colorant having a maximum absorption wavelength in the range of 470–530 nm and a half-width at half-maximum (WHM) of its absorption spectrum of 15–45 nm; a second colorant having a maximum absorption wavelength in the range of 560–620 nm and a WHM of its absorption spectrum of 15–55 nm; and a third colorant having a minimum transmittance wavelength in the range of 400–800 nm in the range of 650–800 nm; wherein the transmittance in any wavelength band of the pigment's absorption wavelength band is 1% or more and less than 50%.

Description

[Technical Field]

[0001] This invention relates to optical thin films, display devices, and compositions for forming colored layers. This application claims priority based on Japanese Patent Application No. 2021-006752, filed on January 19, 2021, the contents of which are incorporated herein by reference. [Previous Technology]

[0002] In terms of improving the color purity of a display device, it is known that a method is used to separate or correct the white light and monochromatic light emitted from the light source of the display device by using a color filter, so as to narrow the half-width at half-maximum.

[0003] When improving color purity using color filters, it is necessary to increase the concentration of the colorant or thicken the filter. Increasing the concentration of the colorant will deteriorate the photolithographic properties. Thickening the filter will deteriorate the pixel shape or viewing angle characteristics. Furthermore, color filters that improve color purity usually have low transmittance, which can easily reduce luminance efficiency.

[0004] In view of the above, a method for improving color purity without using a color filter has been proposed. Patent Document 1 discloses a display device filter in which a color correction layer is provided on a filter substrate having an anti-reflective layer and an electromagnetic wave shielding layer. Since this display device filter has a structure in which the color correction layer is provided on an anti-reflective film, no photolithography step is required during manufacturing, and the luminance efficiency is less likely to decrease. Patent Document 2 discloses a color material suitable for the color correction layer. [Prior Art Documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2007-226239 [Patent Document 2] Japanese Patent No. 6142398 [Summary of the Invention]

[0006] [The problem the invention aims to solve]

[0007] Among the functional pigments contained in the color materials used in the color correction layer, quite a few are not known for their high lightfastness, heat resistance, or resistance to damp heat. Therefore, when using color filters for display devices with such functional pigments, the functionality of the pigments decreases during use, sometimes failing to fully realize their color correction function. The inventors reviewed solutions to this problem and thus completed this invention.

[0008] The object of this invention is to provide an optical thin film with good color correction function and long-term durability. [Means for solving the problem]

[0009] To solve the above-mentioned problems, the first state of the optical film of the present invention comprises: a sheet-like substrate having an ultraviolet shielding rate of 85% or more according to JIS L 1925; an optical functional layer formed on a first side of the aforementioned substrate; and a coloring layer formed on a second side of the aforementioned substrate and containing a pigment; the color difference ΔE*ab before and after the optical film is irradiated for 120 hours with a xenon lamp with an illuminance of 60W / cm2 at a wavelength of 300-400nm under the conditions of temperature 45°C / humidity 50%RH satisfies the following formula (1): ΔE*ab≦5 Formula (1); The pigment contained in the coloring layer contains at least one of the following color materials: a first color material whose maximum absorption wavelength is in the range of 470–530 nm and whose half-width at half-maximum (WHM) of the absorption spectrum is 15–45 nm; a second color material whose maximum absorption wavelength is in the range of 560–620 nm and whose half-width at half-maximum (WHM) of the absorption spectrum is 15–55 nm; and a third color material whose minimum transmittance wavelength is in the range of 650–800 nm within the wavelength range of 400–800 nm; and the transmittance of the pigment in any wavelength band of the absorption wavelength band is 1% or more and less than 50%.

[0010] The second type of display device of the present invention includes: a light source; and a first type of optical film, the optical film being configured such that its second side faces the light source.

[0011] The third embodiment of the present invention comprises a coloring layer forming composition containing: an active energy line curing resin, a photopolymerization initiator, a pigment, an additive, and a solvent. The pigment contains at least one of the following colorants: a first colorant having a maximum absorption wavelength in the range of 470–530 nm and a half-width at half-maximum (WHM) of its absorption spectrum of 15–45 nm; a second colorant having a maximum absorption wavelength in the range of 560–620 nm and a WHM of its absorption spectrum of 15–55 nm; a third colorant having a minimum transmittance wavelength in the wavelength range of 400–800 nm in the range of 650–800 nm; and a transmittance of 1% or more and less than 50% in any wavelength band of the pigment's absorption wavelength band; the additive contains one or more of a free radical scavenger, a peroxide decomposer, or a singlet oxygen quencher. [Effects of the Invention]

[0012] According to the above description of the present invention, an optical thin film with good color correction function and long service life, a display device using the optical thin film, and a composition for forming a color layer used in manufacturing the optical thin film can be provided.

Implementation Method

[0014] [Form for implementing the invention]

[0015] Figures 1 to 4 are schematic cross-sectional views of the optical thin films 1, 1A to 1C of the first to fourth embodiments of the present invention. The upper side in Figures 1 to 4 corresponds to the observation side when observing the displayed image of the display device. Hereinafter, the first embodiment of the present invention will be described with reference to Figure 1. <First Embodiment> Figure 1 is a schematic cross-sectional view of the optical thin film 1 of the present embodiment. The optical thin film 1 includes a sheet-like transparent substrate 10, an optical functional layer 20 formed on the first surface 10a side of the transparent substrate 10, and a coloring layer 30 formed on the second surface 10b side of the transparent substrate 10. Furthermore, the transparent substrate 10 is sometimes simply referred to as substrate 10. In the present embodiment, the direction in which the coloring layer 30, the substrate 10, and the optical functional layer 20 are stacked is called the thickness direction, one side of the thickness direction (the observation side when observing the displayed image of the display device) is called the upper side, and the opposite side is called the lower side.

[0016] The substrate 10 has an ultraviolet (UV) shielding rate of 85% or higher, and the pigment contained in the coloring layer 30 functions as a UV shielding layer (UV absorption layer) for preventing ultraviolet radiation. The UV shielding rate is a value measured according to JIS L 1925 and can be calculated using the following formula: UV shielding rate (%) = 100 - Average transmittance of UV light with wavelengths of 290–400 nm (%)

[0017] Examples of materials for the substrate 10 include polyethylene, polyolefins such as polypropylene, polyesters such as polybutylene terephthalate and polyethylene naphthalate, polyamides such as nylon 6 and nylon 66, polyacrylates such as polymethyl methacrylate (PMMA), triacetyl cellulose (TAC), polyethylene terephthalate (PET), polyimide, polyarylate, polycarbonate, polyacrylate, polyvinyl alcohol, polyvinyl chloride, cyclic olefin copolymers, resins containing norbornene, transparent resins such as polyether ether and polyurethane, and inorganic glass. Among these, films made of polyethylene terephthalate (PET), films made of triacetyl cellulose (TAC), and films made of polymethyl methacrylate (PMMA) are suitable. The thickness of the substrate 10 is not particularly limited, but 10 to 100 μm is preferred. Figure 5 shows the light transmission pattern of a transparent substrate made of these materials. In Figure 5, the UV blocking rates of the substrates are shown below; any of them can be suitable for use as substrate 10. TAC: 91.7% PMMA: 90.2% PET: 88.1%

[0018] The ultraviolet absorption property of the substrate 10 may be imparted, for example, by the resin material used to form the substrate 10 itself, or by the addition of an ultraviolet absorber. There are no particular limitations on the ultraviolet absorber, and compounds based on benzophenone, benzotriazole, triazine, anilide oxalate, or cyanoacrylate may be used.

[0019] The optical functional layer 20 shown in FIG1 has: a hard coating layer 21 adjacent to the first surface 10a; and a low refractive index layer 22 formed on the hard coating layer 21.

[0020] The hard coating 21 is a hard resin layer that can improve the scratch resistance of the optical thin film 1. Furthermore, the refractive index of the hard coating 21 can be higher than that of the low refractive index layer 22. The resin constituting the hard coating 21 is a resin that polymerizes and hardens upon irradiation with active energy lines such as ultraviolet rays or electron beams. For example, monofunctional, difunctional, or trifunctional (meth)acrylate monomers can be used. In this specification, "(meth)acrylate" is a general term for both acrylate and methacrylate, and "(meth)acryl" is a general term for both acrylonitrile and methacryl.

[0021] 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, tributyl (meth)acrylate, glycidyl (meth)acrylate, acrylonitrile, N-vinylpyrrolidone, tetrahydrofurfuryl acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and isocyanate (meth)acrylate. Ester, Isodecyl (meth)acrylate, Dodecyl (meth)acrylate, Tridecyl (meth)acrylate, Hexadecyl (meth)acrylate, Octadecyl (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, methoxypolyethylene glycol (meth)acrylate, methoxypropylene glycol (meth)acrylate, 2-(meth)acrylic acid ethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-phenoxypropyl acrylate, hydrogenated 2-(meth)acrylic acid ethyl phthalate, hydrogenated 2-(meth)acrylic acid ethyl phthalate 2-(meth)propenyloxypropyl ester, hexahydrohydrogenated 2-(meth)propenyloxypropyl ester, tetrahydrohydrogenated 2-(meth)propenyloxypropyl ester, dimethylamine ethyl ester (meth)acrylate, trifluoroethyl ester (meth)acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropropyl (meth)acrylate, and adamantane derivatives such as adamantane acrylates with monovalent mono(meth)acrylates derived from 2-adamantane and adamantanediol.

[0022] Examples of difunctional (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, ethylene glycol di(meth)acrylate oxyhexanediol di(meth)acrylate, propionyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene oxide neopentyl glycol di(meth)acrylate, hydroxytrimethylacetic acid neopentyl glycol di(meth)acrylate, and other di(meth)acrylates.

[0023] Examples of trifunctional or higher (meth)acrylate compounds include: trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, tri(meth)acrylate with 2-hydroxyethyl isocyanate, glycerol tri(meth)acrylate, neopentyl tetral tri(meth)acrylate, dinepentyl tetral tri(meth)acrylate, di-trimethylolpropane tri(meth)acrylate, and other trifunctional (meth)acrylates. Ester compounds; and polyfunctional (meth)acrylate compounds with three or more functions, such as neopentyl tetroxide tetra(meth)acrylate, di-trimethylolpropane tetra(meth)acrylate, di-neopentyl tetroxide penta(meth)acrylate, di-trimethylolpropane penta(meth)acrylate, di-neopentyl tetroxide hexa(meth)acrylate, and di-trimethylolpropane hexa(meth)acrylate; and polyfunctional (meth)acrylate compounds formed by replacing a portion of these (meth)acrylates with alkyl groups or ε-caprolactones.

[0024] Furthermore, as an active energy line curable resin, urethane (meth)acrylate can also be used. Examples of urethane (meth)acrylates include those obtained by reacting a hydroxyl-containing (meth)acrylate monomer with an isocyanate monomer or prepolymer and a polyester polyol.

[0025] Examples of urethane (meth)acrylates include: neopentyl tert-acrylate hexamethylene diisocyanate urethane prepolymer, dinepentyl tert-acrylate hexamethylene diisocyanate urethane prepolymer, neopentyl tert-acrylate toluene diisocyanate urethane prepolymer, dinepentyl tert-acrylate toluene diisocyanate urethane prepolymer, neopentyl tert-acrylate isophorone diisocyanate urethane prepolymer, dinepentyl tert-acrylate isophorone diisocyanate urethane prepolymer, etc.

[0026] The above-mentioned resin may be used in combination with one type or in combination with two or more types. Furthermore, the above-mentioned resin may be a monomer or a partially polymerized oligomer in the composition for forming the hard coating. The hardness of the hard coating 21 is preferably H or higher, meaning its surface has a pencil hardness of 500g or higher.

[0027] To suppress the degradation of the pigment contained in the coloring layer 30, the hard coating layer 21 may also contain an ultraviolet absorber. Similar to the substrate 10, the ultraviolet shielding rate of the hard coating layer 21 is preferably 85% or higher. The absorption wavelength range of the ultraviolet absorber contained in the hard coating layer 21 in the ultraviolet region is preferably in the range of 290–370 nm. Examples of such ultraviolet absorbers include benzophenone-based, benzotriazole-based, triazine-based, oxaliplatin-based, and cyanoacrylate-based compounds. The ultraviolet absorber is incorporated to suppress the degradation of the pigment contained in the coloring layer 30. Therefore, an ultraviolet absorber that absorbs light in the ultraviolet region that causes degradation of the pigment contained in the coloring layer 30 is used. However, when the composition containing the ultraviolet absorber is cured, if the ultraviolet absorption of the ultraviolet absorber is excessive, the curing of the composition becomes insufficient, resulting in insufficient surface hardness of the obtained optical film. Therefore, in this embodiment, in the UV shielding layer (UV absorption layer) of the hardened film containing a composition of an energy-line hardening compound, a photopolymerization initiator, and a UV absorber, a UV absorber with an absorption wavelength range in the UV region that differs from the absorption wavelength range of the photopolymerization initiator in the UV region is used. This suppresses the UV absorber from hindering the hardening of the hardened film. Furthermore, since the hardened film can be hardened to a set degree of hardness, a hardened layer with the target hardness can be reliably obtained. As a photopolymerization initiator with an absorption wavelength range different from the absorption wavelength range of the UV absorber contained in any layer constituting the UV shielding layer (the wavelength range that contributes to the degradation of the pigment contained in the coloring layer 30), a phosphine oxide-based photopolymerization initiator is preferably used. Examples of phosphine oxide-based photopolymerization initiators include diphenyl(2,4,6-trimethylbenzyl)phosphine oxide or phenylbis(2,4,6-trimethylbenzyl)phosphine oxide. By making the absorption wavelength range of the ultraviolet absorber different from that of the photopolymerization initiator, the curing obstacle during the formation of the ultraviolet shielding layer containing the ultraviolet absorber can be suppressed, and the pigment contained in the coloring layer 30 after curing can be suppressed from deterioration due to ultraviolet radiation.

[0028] Other photopolymerization initiators used as components for hard coating formation may include, for example, 2,2-ethoxyacetophenone, 1-hydroxycyclohexylphenyl ketone, dibenzoyl, benzoin, benzoin methyl ether, benzoin ethyl ether, p-chlorobenzophenone, p-methoxybenzophenone, milchnerone, acetophenone, 2-chlorothiaxanone, etc. One of these may be used alone, or two or more may be used in combination.

[0029] Furthermore, solvents used as components for forming hard coatings may include ethers such as dibutyl ether, dimethoxymethane, dimethoxyethylene, diethoxyethylene, propylene oxide, 1,4-dimethyl ether, 1,3-dioxolane, 1,3,5-trimethyl ether, tetrahydrofuran, anisole, and phenethyl ether; ketones such as acetone, methyl ethyl ketone, diethyl ketone, diacetone, diisobutyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, and methylcyclopentanone; 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 celecoxib such as methyl celecoxib, celecoxib, butyl celecoxib, and celecoxib acetate. These may be used alone or in combination of two or more.

[0030] Furthermore, the composition for forming a hard coating may also contain metal oxide microparticles to adjust the refractive index or impart hardness. Examples of metal oxide microparticles include: zirconium oxide, titanium oxide, niobium oxide, antimony trioxide, antimony pentoxide, tin oxide, indium oxide, indium tin oxide, zinc oxide, etc.

[0031] Furthermore, the composition for forming the hard coating may also contain any one of the following: a silicon oxide, a fluorinated silane compound, a fluoroalkyl silazane, a fluoroalkyl silane, a fluorinated silicon compound, or a silane coupling agent containing a perfluoropolyether group, which imparts water-repellent and / or oil-repellent properties and improves stain resistance.

[0032] As other additives, leveling agents, defoamers, antioxidants, light stabilizers, photosensitizers, conductive materials, etc., may be added to the composition for forming hard coatings.

[0033] When the optical thin film 1 is used in a display device, the low refractive index layer 22 is disposed on the side closest to the user (visual observer) viewing the display. The low refractive index layer 22 prevents strong reflection of external light and improves the visual legibility of the display device.

[0034] The low refractive index layer 22 may be a layer containing inorganic materials or inorganic compounds. Examples of inorganic materials or inorganic compounds include microparticles such as LiF, MgF, 3NaF·AlF, AlF, and Na3AlF6, or silica microparticles. Furthermore, if the silica microparticles are porous silica microparticles or hollow silica microparticles with pores inside, they are very effective for reducing the refractive index of the low refractive index layer. In addition, the photopolymerization initiator, solvent, and other additives described in the hard coating layer 21 may also be appropriately incorporated into the composition for forming the low refractive index layer.

[0035] The refractive index of the low refractive index layer 22 only needs to be lower than that of the hard coating layer 21, preferably below 1.55. Furthermore, the film thickness of the low refractive index layer 22 is not particularly limited, but 40 nm to 1 μm is preferred.

[0036] The low refractive index layer 22 may also contain any of the following: silicon oxide, fluorinated silane compound, fluoroalkyl silazane, fluoroalkyl silane, fluorinated silicon compound, or silane coupling agent containing perfluoropolyether group. If such material is used, the low refractive index layer 22 can be endowed with water-repellent and / or oil-repellent properties, thereby improving its anti-fouling properties.

[0037] The coloring layer 30 contains a pigment for selectively absorbing wavelengths of visible light. The coloring layer 30 may be composed of a matrix resin containing a pigment in a resin comprising an active energy line curing resin. The pigment includes at least one of the three types of colorants listed below. The type of colorant is not limited to one, and may include two or more colorants. The first colorant has a maximum absorption wavelength in the range of 470 nm to 530 nm, and a full width at half maximum (FWHM) of the absorption spectrum of 15 nm to 45 nm. The second colorant has a maximum absorption wavelength in the range of 560 nm to 620 nm, and a full width at half maximum (FWHM) of the absorption spectrum of 15 nm to 55 nm. The third colorant has a minimum transmittance wavelength in the range of 400 to 800 nm, in the range of 650 to 800 nm. Furthermore, in the following description, the full width at half maximum (FWHM) of the absorption spectrum refers to the full width at half maximum (FWHM). In the coloring layer 30, the transmittance of the maximum absorption wavelength in any one of the absorption wavelength bands of the aforementioned color material is 1% or more and less than 50%. By using color materials with the above-mentioned absorption characteristics as the first to third color materials contained in the coloring layer 30, the coloring layer 30 can absorb visible light in the wavelength range with relatively low luminous intensity within the visible light emitted by the display device. For example, using the first, second, and third color materials, visible light in the wavelength range of 400 to 800 nm can be absorbed by the coloring layer 30 in the ranges of 470 nm to 530 nm, 560 nm to 620 nm, and 650 nm to 800 nm, respectively. The wavelengths absorbed by the first, second, and third color materials, for example, are in the spectroscopic spectrum of the organic EL display device shown in Figure 6 when displaying white, where the visible light emitted by the display device overlaps with the wavelength range with relatively low luminous intensity. Furthermore, the display device is not limited to an organic EL display device and can also be other display devices.

[0038] As the first to third color materials, the color materials that can be used contain one or more compounds selected from the group consisting of compounds having any one of the following structures: porphyrin, phthalocyanine, azo, cyanine, squaric acid cyanine, coumarin, polyene, quinone, tetra-diporphyrin, pyrromethene, and indigo, and their metal complexes. In particular, it is more preferable to use metal complexes having an intramolecular porphyrin, pyrromethene, phthalocyanine, or squaric acid cyanine structure. For example, a pyrromethene cobalt complex can be used as the first color material. Furthermore, a tetraazaporphyrin copper complex can be used as the second color material.

[0039] The coloring layer 30 may also contain at least one of a free radical scavenger, a singlet oxygen quencher, and a peroxide decomposer. The color material contained in the coloring layer 30 is also promoted under the influence of oxygen and deteriorates by light, heat, etc. By mixing the free radical scavenger into the coloring layer 30, free radicals during pigment oxidation and deterioration can be captured, preventing the deterioration of the color material caused by auto-oxidation, and further extending the duration of the color correction function. Furthermore, by mixing the singlet oxygen quencher into the coloring layer 30, highly reactive singlet oxygen, which has the property of easily oxidizing and deteriorating (fading) pigments, is deactivated, thereby inhibiting the oxidation and deterioration (fading) of pigments. When the peroxide decomposer is mixed into the coloring layer 30, the peroxides produced during pigment oxidation and deterioration are decomposed by the peroxide decomposer, thus stopping the auto-oxidation cycle and inhibiting pigment deterioration (fading). The free radical scavenger and the singlet oxygen quencher may also be used together. Furthermore, the peroxide decomposer may also be combined.

[0040] Hindered amine light stabilizers can be used as free radical scavengers. Hindered amine light stabilizers with a molecular weight of 2000 or higher are particularly advantageous because they provide high fading inhibition. When the molecular weight of the free radical scavenger is low, it is prone to volatility, resulting in fewer molecules remaining within the colored layer 30, making it difficult to achieve sufficient fading inhibition. Suitable materials for use as free radical scavengers include, for example, Chimassorb 2020 FDL and Chimassorb 944 FDL manufactured by BASF, Tinuvin 622, and LA-63P manufactured by ADEKA.

[0041] As singlet oxygen quenchers, examples include: transition metal complexes, pigments, amines, phenols, and sulfides. Particularly suitable materials include transition metal complexes of dialkyl phosphate, dialkyl dithiocarbamate, or benzodithiophenol or similar dithiophenols. As the central metal of such transition metal complexes, nickel, copper, or cobalt may be used.

[0042] A peroxide decomposing agent, which decomposes the peroxides produced during pigment oxidation and deterioration, thereby stopping the auto-oxidation cycle and inhibiting pigment deterioration (fading). Phosphorus-based antioxidants and sulfur-based antioxidants can be used as peroxide decomposing agents.

[0043] As phosphorus-based antioxidants, examples include: 2,2'-methylenebis(4,6-di-tertiary-butyl-1-phenoxy)(2-ethylhexyloxy)phosphine, 3,9-bis(2,6-di-tertiary-butyl-4-methylphenoxy)-2,4,8,10-tetraoxazaspiro-3,9-diphosazaspiro[5.5]undecane and 6-[3-(3-tertiary-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tertiary-butyldibenzo[d,f][1,3,2]dioxophosphazene, etc.

[0044] As sulfur-based antioxidants, examples include: 2,2-bis({[3-(dodecylthio)propionic acid]oxy}methyl)-1,3-propanediyl-bis[3-(dodecylthio)propionate], 2-mercaptobenzimidazole, dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearate-3,3'-thiodipropionate, neopentyltetroxy-tetra(3-laurylthiopropionate), 2-mercaptobenzothiazole, etc.

[0045] The optical thin film 1 can be manufactured by forming an optical functional layer 20 on a first surface 10a of a substrate 10 and a colored layer 30 on a second surface 10b. The hard coating layer 21, the low refractive index layer 22, and the colored layer 30 can be formed, for example, by coating a coating liquid containing the constituent materials of each layer and then drying it. Furthermore, the low refractive index layer 22 can also be formed, for example, by evaporation or sputtering. Either the optical functional layer 20 or the colored layer 30 can be formed first.

[0046] If a hard coating 21 is formed using an energy line curing compound such as an ultraviolet-curable resin, it can be easily formed. In this case, the hard coating 21 can be formed by coating a coating liquid containing an energy line curing compound, a polymerization initiator, and an ultraviolet absorber, and irradiating the corresponding energy line. When using an ultraviolet-curable resin, as mentioned above, it is preferable that the absorption wavelength range in the ultraviolet region of the photopolymerization initiator is different from the absorption wavelength range in the ultraviolet region of the ultraviolet absorber.

[0047] The optical thin film 1 can be used as a color correction filter and is disposed inside the display device. During disposal, the color layer 30 is positioned with the light source facing it. When light emitted from the light source passes through the color layer 30, wavelength components near the maximum absorption wavelength of the contained color material are absorbed. This improves the color purity of the display device. Furthermore, unlike a color filter, since it is not necessary to increase the color material concentration to such a high level, the brightness of the display device is not excessively reduced, thus improving color purity.

[0048] Although the colorant contained in the coloring layer 30 has excellent color correction function, its resistance to light, especially to ultraviolet light, is insufficient. Therefore, if exposed to ultraviolet light, it will deteriorate over time and become unable to absorb light near its maximum absorption wavelength. In this embodiment, when the optical thin film 1 is mounted on a display device with the first surface 10a of the substrate 10 facing the observation side and the second surface 10b facing the light source side, external light containing ultraviolet light incident on the display screen penetrates the substrate 10 and then enters the coloring layer 30. Since the substrate 10 has a high ultraviolet shielding rate, most of the ultraviolet light contained in the external light cannot penetrate the substrate 10 and cannot reach the coloring layer 30. Therefore, in the optical thin film 1, the chromaticity difference ΔE*ab before and after the lightfastness test (irradiated for 120 hours under xenon lamp illumination of 60W / cm2 (300~400nm), temperature of 45℃ / humidity of 50%RH) can satisfy the following equation (1): ΔE*ab≦5 Equation (1). That is, it can prevent the deterioration of the color material contained in the color layer 30 and make the color correction function last for a long time. Furthermore, ΔE*ab in Equation (1) is the chromaticity difference standardized according to CIE (International Commission on Illumination).

[0049] <Second Embodiment> A second embodiment of the present invention will be described with reference to FIG2. In the following description, common components to those already described are given the same reference numerals, and repeated descriptions are omitted.

[0050] Figure 2 is a cross-sectional schematic diagram showing the layer composition of the optical thin film 1A of this embodiment. The optical thin film 1A includes a transparent substrate 10, an optical functional layer 20 formed on the first surface 10a side of the substrate 10, and a coloring layer 30 formed on the second surface 10b side of the substrate 10. The optical thin film 1A includes an anti-glare layer (AG layer) 23 as the optical functional layer 20.

[0051] The anti-glare layer 23 has a surface with fine irregularities, which scatter external light to reduce the amount of external light entering the layer. The anti-glare layer 23 can be formed by coating an anti-glare layer forming composition containing an active energy line curing resin and, as needed, organic microparticles and / or inorganic microparticles, and then curing it. The active energy line curing resin used as the anti-glare layer forming composition can be the resin described in the hard coating layer 21. This improves the scratch resistance of the optical film 1A. The film thickness of the anti-glare layer 23 is not particularly limited, but 1 to 10 μm is preferred.

[0052] The organic microparticles used in the composition for forming the anti-glare layer are mainly materials that form fine irregularities on the surface of the anti-glare layer 23, giving it the function of diffusing external light. As organic microparticles, resin particles composed of light-transmitting resin materials such as acrylic resin, polystyrene resin, styrene-(meth)acrylate copolymer, polyethylene resin, epoxy resin, polysiloxane resin, polyvinylidene fluoride, and polyvinyl fluoride resin can be used. To adjust the refractive index or the dispersibility of the resin particles, two or more resin particles with different materials (refractive indices) can also be mixed and used.

[0053] The inorganic microparticles used in the composition for forming the anti-glare layer are mainly materials used to adjust the sedimentation or aggregation of organic microparticles in the anti-glare layer 23. As inorganic microparticles, silica microparticles, metal oxide microparticles, and various mineral microparticles can be used. For example, colloidal silica or silica microparticles surface-modified with reactive functional groups such as (meth)acrylic acid can be used. For example, bauxite, zinc oxide, tin oxide, antimony oxide, indium oxide, titanium oxide, and zirconium oxide can be used. For example, mica, synthetic mica, vermiculite, microcrystalline kaolinite, iron microcrystalline kaolinite, bentonite, aluminum bentonite, magnesium bentonite, lithium bentonite, talc, iron bentonite, sodium silicate, illite, sodium silicate hydrous, layered titanate, bentonite, and synthetic bentonite can be used. Mineral microparticles can be either natural or synthetic (including substitutes and derivatives), or a mixture of both. Layered organoclay is preferred among mineral microparticles. Layered organoclay refers to the introduction of organonium ions between the layers of bentonite. There are no restrictions on the organonium ions as long as they can be organically converted using the cation exchange capacity of bentonite. When using layered organoclay minerals as mineral microparticles, the aforementioned synthetic bentonite is suitable. Synthetic bentonite has the functions of increasing the viscosity of the coating liquid for forming the anti-glare layer, inhibiting the sedimentation of resin particles and inorganic microparticles, and adjusting the surface irregularities of the optical functional layer.

[0054] The composition for forming the anti-glare layer may contain any one of silicon oxide, fluorinated silane compound, fluoroalkyl silazane, fluoroalkyl silane, fluorinated silicone compound, or silane coupling agent containing perfluoropolyether group. By means of these materials, the anti-glare layer 23 can be endowed with water-repellent and / or oil-repellent properties, thereby improving its anti-fouling properties.

[0055] The anti-glare layer 23 can also be formed by unevenly distributing the material into layers with relatively high refractive index and relatively low refractive index sequentially stacked from the side (bottom side) of the colored layer 30. For example, the anti-glare layer 23 formed by unevenly distributing the material can be formed by coating a low-refractive-index material containing surface-modified silica microparticles or hollow silica microparticles, and a composition containing a high-refractive-index material, utilizing the difference in surface free energy between the two to achieve phase separation. When the anti-glare layer 23 is composed of two phase-separated layers, it is preferable to adjust the refractive index of the layer with relatively high refractive index on the side of the colored layer 30 to 1.50 to 2.40, and the refractive index of the layer with relatively low refractive index on the surface side of the optical thin film 1A to 1.20 to 1.55.

[0056] An optical film 1A can be manufactured by forming an anti-glare layer 23 on a first surface 10a of a substrate 10 and sequentially forming a coloring layer 30 on a second surface 10b of the substrate 10. The anti-glare layer 23 can be formed, for example, by coating and drying a coating liquid containing the constituent materials of each layer. The optical film 1A of this embodiment, like the first embodiment described above, can prevent the deterioration of the color material contained in the coloring layer 30 and reduce the penetration of external light.

[0057] <Third Embodiment> A third embodiment of the present invention will be described with reference to FIG3. In the following description, common components to those already described will be indicated by the same reference numerals, and repeated descriptions will be omitted. FIG3 is a cross-sectional schematic diagram showing the layer structure of the optical thin film 1B of this embodiment. The optical thin film 1B includes a transparent substrate 10, an optical functional layer 20 formed on a first surface 10a of the substrate 10, and a coloring layer 30 formed on a second surface 10b of the substrate 10. The optical thin film 1B includes an anti-glare layer 23, which is the optical functional layer 20, and a low refractive index layer 22 formed on the anti-glare layer 23. The anti-glare layer 23 only needs to have a higher refractive index than the low refractive index layer 22.

[0058] An optical thin film 1B can be manufactured by sequentially forming an anti-glare layer 23 on a first surface 10a of a substrate 10, forming a low refractive index layer 22 on the anti-glare layer 23, and forming a coloring layer 30 on a second surface 10b of the substrate 10. The optical thin film 1B of this embodiment can achieve the same effect as the embodiments described above, while also performing the optical function based on the optical functional layer 20.

[0059] <Fourth Embodiment> A fourth embodiment of the present invention will be described with reference to FIG4. In the following description, common components to those already described will be indicated by the same reference numerals, and repeated descriptions will be omitted. FIG4 is a cross-sectional schematic diagram showing the layer structure of the optical thin film 1C of this embodiment. The optical thin film 1C includes a transparent substrate 10, an optical functional layer 20 formed on a first surface 10a of the substrate 10, and a coloring layer 30 formed on a second surface 10b of the substrate 10. The optical thin film 1C includes an oxygen barrier layer 40 and an optical functional layer 20 formed on the oxygen barrier layer 40. The optical functional layer 20 includes a hard coating layer 21 and a low refractive index layer 22 formed on the hard coating layer 21.

[0060] The oxygen barrier layer 40 is a transparent layer with light transmittance, having an oxygen transmittance of 10 cc / (m²·day·atm) or less, preferably 5 cc / (m²·day·atm) or less, and further preferably 1 cc / (m²·day·atm) or less. The forming material of the oxygen barrier layer 40 is preferably containing polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer (EVOH), vinylidene chloride, or silicone resin, etc. Materials such as MAXIVE (registered trademark) manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC., EVAL manufactured by Kuraray Co., Ltd., Saran Latex from Asahi Kasei Corporation, and Saran Resin can be used. Furthermore, the thickness of the oxygen barrier layer 40 is not particularly limited, as long as the desired oxygen barrier properties are achieved.

[0061] Furthermore, inorganic particles (particles composed of inorganic compounds) may also be dispersed in the oxygen barrier layer 40. These inorganic particles further reduce oxygen penetration and inhibit the oxidative degradation (fading) of the coloring layer 30. The size or content of the inorganic particles is not particularly limited, as long as it is appropriately set according to the thickness of the oxygen barrier layer 40. It is preferable that the size (maximum length) of the inorganic particles dispersed in the oxygen barrier layer 40 is smaller than the thickness of the oxygen barrier layer 40; the smaller the better. Moreover, the size of the inorganic particles dispersed in the oxygen barrier layer 40 may be uniform or non-uniform. Specifically, examples of inorganic particles dispersed in the oxygen barrier layer 40 include silicon dioxide particles, bauxite particles, silver particles, copper particles, titanium particles, zirconium oxide particles, and tin particles.

[0062] In this embodiment, the number or position of the oxygen barrier layer 40 can be appropriately set. The oxygen barrier layer 40 only needs to be deposited on the observer side above the coloring layer 30. For example, the oxygen barrier layer 40 can be disposed between the substrate 10 and the coloring layer 30, or on the second surface 10b side of the substrate 10. Furthermore, in the optical films 1A and 1B of the second and third embodiments, the oxygen barrier layer 40 can also be further disposed between the substrate 10 and the anti-glare layer 23. Furthermore, in the optical film 1B of the third embodiment, the oxygen barrier layer 40 can also be further disposed between the anti-glare layer 23 and the low refractive index layer 22. By further disposing of the oxygen barrier layer 40, similar to the fourth embodiment, fading caused by pigment oxidation due to light, heat, etc., under the influence of oxygen in the external gas can be further suppressed.

[0063] An optical thin film 1C can be manufactured by forming an oxygen barrier layer 40 on a first surface 10a of a substrate 10, forming a hard coating layer 21 and a low refractive index layer 22 on the oxygen barrier layer 40 in sequence, and forming a coloring layer 30 on a second surface 10b of the substrate 10.

[0064] In the optical thin film 1C of this embodiment, when installed in a display device as described above, oxygen contained in the external gas will not reach the color layer if it does not penetrate the oxygen barrier layer 40. This suppresses the degradation of the color material caused by light, heat, etc., under the influence of oxygen in the external gas, allowing the color correction function to continue for a long time.

[0065] For example, other oxygen barrier layers may be further provided between the coloring layer 30 and the substrate 10 to form a structure in which the substrate 10 is held by the oxygen barrier layer.

[0066] In this invention, the optical functional layer 20 is not limited to the above-described configuration. For example, an antireflective layer consisting of multiple combinations of a low-refractive-index layer 22 and a high-refractive-index layer, an antireflective layer comprising a high-refractive-index layer and an anti-glare layer 23, an antireflective layer comprising a high-refractive-index layer, an anti-glare layer 23 and a low-refractive-index layer 22, or an antireflective layer comprising an anti-glare layer 23 are also examples of the optical functional layer 20 in this invention. Furthermore, at least one of the high-refractive-index layer, the anti-glare layer 23, or the low-refractive-index layer 22 may have antistatic properties, and at least one of the high-refractive-index layer, the anti-glare layer 23, or the low-refractive-index layer 22 may have antifouling properties. For example, adding an antistatic agent to the high-refractive-index layer and the anti-glare layer 23 can impart antistatic properties. By containing a water-repellent and / or oil-repellent material in the low-refractive-index layer 22, antifouling properties can be imparted to the function of the low-refractive-index layer 22. Furthermore, the high refractive index layer or the anti-glare layer 23 can also be endowed with anti-fouling properties. Moreover, at least one of the high refractive index layer, the anti-glare layer 23, or the low refractive index layer 22 can be endowed with both antistatic and anti-fouling properties. This allows for the endowment of more functions to the optical functional layer. Furthermore, the resin used in the composition for forming the high refractive index layer can also be the active energy line curing resin described in the hard coating layer 21. This, in addition to the function of preventing reflection, can also improve the scratch resistance of the optical thin film. [Example]

[0067] The optical thin film of the present invention will be further described using examples and comparative examples. The present invention is not limited in any way by the specific contents of the following examples.

[0068] (Examples 1-17, Comparative Examples 1-14) Optical thin films 1-24, composed of the layers shown in Tables 1 and 2 in the following Examples and Comparative Examples, were fabricated, and the characteristics of the fabricated thin films were evaluated. Furthermore, the optical characteristics of organic EL display devices 1-7 using optical thin films 7, 13, 14, 21-24 shown in Table 3 were confirmed by simulation.

[0069] [Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 Optical thin films Optical thin film 1 Optical thin film 2 Optical thin film 3 Optical thin film 4 Optical thin film 5 Optical thin film 6 Optical thin film 7 Optical thin film 8 Optical thin film 9 Optical thin film 10 Optical thin film 11 Optical thin film 12 Optical thin film 13 Optical thin film 14 Functional layer 1 Low refractive index layer 1 - Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Functional layer 2 Hard coating 2 Hard coating 2 Anti-glare layer 1 Anti-glare layer 1 Hard coating 2 Hard coating 2 Hard coating 2 Hard coating 2 Hard coating 2 Hard coating 2 Hard coating 2 Hard coating 1 Hard coating 2 Hard coating 2 Functional layer 3 - - - - - - - - - - oxygen barrier layer 1 - - Substrate TAC TAC TAC TAC TAC TAC TAC PMMA1 PET1 PET2 TAC TAC TAC TAC Color layer Color layer 1 Color layer 1 Color layer 1 Color layer 1 Color layer 5 Color layer 2 Color layer 3 Color layer 3 Color layer 3 Color layer 3 Color layer 3 Color layer 5 Color layer 6 Color layer 7

[0070] [Table 2] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Optical thin films Optical thin film 15 Optical thin film 16 Optical thin film 17 Optical thin film 18 Optical thin film 19 Optical thin film 20 Optical thin film 21 Optical thin film 22 Optical thin film 23 Optical thin film 24 Functional layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Functional layer 2 Hard coating 2 Hard coating 2 Hard coating 2 Hard coating 3 Hard coating 2 Hard coating 2 Hard coating 1 Hard coating 2 Hard coating 2 Hard coating 2 Functional layer 3 Color layer 1 Color layer 4 - - - - - - - - Substrate TAC TAC PMMA2 TAC PMMA2 PMMA2 TAC TAC TAC TAC Color layer - - Color layer 1 Color layer 1 Color layer 6 Color layer 7 - Color layer 8 Color layer 9 Color layer 10

[0071] [Table 3] Example 15 Example 16 Example 17 Comparative Example 11 Comparative Example 12 Comparative Example 13 Comparative Example 14 Organic EL display device Display device 1 Display device 2 Display device 3 Display device 4 Display device 5 Display device 6 Display device 7 Optical thin films Optical thin film 7 Optical thin film 13 Optical thin film 14 Optical thin film 21 Optical thin film 22 Optical thin film 23 Optical thin film 24 Functional layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Low refractive index layer 1 Functional layer 2 Hard coating 2 Hard coating 2 Hard coating 2 Hard coating 1 Hard coating 2 Hard coating 2 Hard coating 2 Substrate TAC TAC TAC TAC TAC TAC TAC Color layer Color layer 3 Color layer 6 Color layer 7 - Color layer 8 Color layer 9 Color layer 10

[0072] <Fabrication of Optical Thin Film> The following describes the method for forming each layer.

[0073] [Formation of Colored Layer] (Materials Used in Composition for Forming Colored Layer) The following materials are used in the composition for forming a colored layer. Furthermore, the maximum absorption wavelength and half-width at half-maximum of the colorant are calculated from the characteristic values ​​in the hardened coating film using spectral transmittance. • First colorant: Dye-1, pyrrole-methylene cobalt complex dye as described in Chemical 1 (maximum absorption wavelength 493nm, full width at half maximum 26nm) • Second colorant: Dye-2, tetraazaporphyrin copper complex dye (FDG-007 manufactured by Yamada Chemical Co., Ltd., maximum absorption wavelength 595nm, full width at half maximum 22nm) Dye-3, tetraazaporphyrin copper complex dye (PD-311S manufactured by Yamamoto Chemical Co., Ltd., maximum absorption wavelength 586nm, full width at half maximum 22nm) • Third colorant: Dye-4, phthalocyanine copper complex dye (FDN-002 manufactured by Yamada Chemical Co., Ltd., maximum absorption wavelength 800nm ​​(the wavelength with the lowest transmittance in the wavelength range of 400-800nm ​​is 800nm)) • Colorants other than the first to third colorants: Dye-5 Dye (FDG-003, manufactured by Yamada Chemical Co., Ltd., maximum absorption wavelength 545nm, half-width at half-maximum 79nm) Dye-6 dye (FDG-004, manufactured by Yamada Chemical Co., Ltd., maximum absorption wavelength 575nm, half-width at half-maximum 63nm) • Additives: Hindered amine light stabilizer Chimassorb 944 FDL (manufactured by BASF JAPAN, molecular weight 2000-3100) Hindered amine light stabilizer Tinuvin 249 (manufactured by BASF JAPAN, molecular weight 482) Singlet oxygen quencher D1781 (manufactured by Tokyo Chemical Industry Co., Ltd., nickel dithiocarbamate complex) • UV absorbers: Tinuvin 479 (manufactured by BASF JAPAN, maximum absorption wavelength 322nm) LA-36 (manufactured by ADEKA, maximum absorption wavelengths 310nm, 350nm) • Resin for curing with active energy lines: UA-306H (manufactured by Kyoeisha Chemical Co., Ltd., neopentyl terephthalate hexamethylene diisocyanate carbamate prepolymer) DPHA (dineopentyl terephthalate hexaacrylate) PETA (neopentyl terephthalate triacrylate) • Initiator (photopolymerization initiator): Omnirad TPO (manufactured by IGM Resing BV, absorption wavelength peak 275nm, 379nm) • Solvent: MEK (methyl ethyl ketone), methyl acetate

[0074] (Chemical 1)

[0075] (Coloring layer formation) (Substrate) Use the following transparent substrate. • TAC: Triacetyl cellulose film (TG60UL manufactured by Fujifilm, substrate thickness 60μm, UV blocking rate 92.9%) • PMMA1: Polymethyl methacrylate film (W001U80 manufactured by Sumitomo Chemical, substrate thickness 80μm, UV blocking rate 93.4%) • PMMA2: Polymethyl methacrylate film (W002N80 manufactured by Sumitomo Chemical, substrate thickness 80μm, UV blocking rate 13.9%) • PET1: Polyethylene terephthalate film (SRF manufactured by Toyobo, substrate thickness 80μm, UV blocking rate 88.3%) • PET2: Polyethylene terephthalate film (TOR20 manufactured by SKC, substrate thickness 40μm, UV blocking rate 88.6%) The coloring layer forming compositions shown in Table 4 are coated on one side of a transparent substrate and dried in an oven at 80°C for 60 seconds. Then, the coating is hardened by irradiation with ultraviolet light using an ultraviolet irradiation device at an irradiation linearity of 150 mJ / cm2 (manufactured by Fusion UV Systems Japan KK, light source H bulb), and the thickness of the hardened film is adjusted to 5.0 μm to form colored layers 1 to 10. Furthermore, the amount added is by mass ratio.

[0076] [Table 4] Color layer 1 Color layer 2 Color layer 3 Color layer 4 Color layer 5 Color layer 6 Color layer 7 Color layer 8 Color layer 9 Color layer 10 color material 1st color material Dye-1 - Dye-1 - Added amount 0.2% 0.2% 0.2% 0.2% 0.2% 0.1% - 0.2% - 2nd color material - Dye-2 Dye-3 / Dye-2=60 / 40 - Added amount - 0.2% 0.5% - 3rd color material - Dye-4 - - - Added amount - 1.5% - - - 4th color material - Dye-5 Dye-6 Added amount - 0.2% 0.2% Additives Kind - Chimassorb 944FDL Chimassorb 944FDL / D1781 - Tinuvin 249 - - Chimassorb 944FDL / D1781 - ratio - 100 67 / 33 - 100 - - 67 / 33 - Added amount - 1.4% 2.2% - 1.4% - - 3.2% - UV absorber Kind - Tinuvin4 79 / LA36 - ratio - 40 / 60 - Added amount - 3.20% - Active energy lines Hardened resin Kind UA-306H / DPHA / PETA ratio 70 / 20 / 10 Added amount 45.2% 43.8% 43.0% 42.0% 43.8% 43.8% 45.2% 41.5% 45.2% 45.2% Photopolymerization initiator type Omnirad TPO Added amount 4.6% solvent type MEK / methyl acetate ratio 50 / 50 Added amount 50%

[0077] [Formation of oxygen barrier layer] ・Composition for forming oxygen barrier layer: 80% aqueous solution of PVA117 (manufactured by Kuraray Co., Ltd.)

[0078] (Oxygen barrier layer formation) The above-mentioned composition for forming an oxygen barrier layer is coated on a transparent substrate and dried to form an oxygen barrier layer 1 of Table 1 with an oxygen permeability of 1cc / (m2・day・atm).

[0079] [Formation of Optical Functional Layer] (Composition for Hard Coating Formation) The following materials are used for the composition for hard coating formation: ・UV Absorber: Tinuvin 479 (manufactured by BASF JAPAN, maximum absorption wavelength 322nm) LA-36 (manufactured by ADEKA, maximum absorption wavelengths 310nm, 350nm) ・Active Energy Line Curing Resin: UA-306H (manufactured by Kyoei Chemical Co., Ltd., neopentyl terephthalate hexamethylene diisocyanate carbamate prepolymer) DPHA (dineopentyl terephthalate hexaacrylate) PETA (neopentyl terephthalate triacrylate) ・Initiator: Omnirad TPO (manufactured by IGM Resins BV, peak absorption wavelengths 275nm, 379nm) Omnirad 184 (manufactured by IGM Resins BV, peak absorption wavelengths 243nm, 331nm) ・Solvent: MEK (methyl ethyl ketone) methyl acetate

[0080] (Hard Coating Formation) The hard coating forming composition shown in Table 5 is coated onto a transparent substrate or an oxygen barrier layer, dried in an oven at 80°C for 60 seconds, and then irradiated with ultraviolet light (Fusion UV Systems Japan KK, light source H bulb) at an irradiation dose of 150 mJ / cm² to harden the coating, forming hard coatings 1 to 3 of Tables 1 and 2 with a hardened film thickness of 5.0 μm. Furthermore, since hard coatings 1 and 3 contain ultraviolet absorbers, they also serve as ultraviolet shielding layers.

[0081] [Table 5] Hard coating 1 Hard coating 2 Hard coating 3 UV absorber type Tinuvin479 / LA36 - Tinuvin479 / LA36 ratio 40 / 60 - 40 / 60 Added amount 3.2% - 3.2% Active energy lines hardened resin type UA-306H / DPHA / PETA ratio 70 / 20 / 10 Added amount 42.2% 45.4% 42.2% Photopolymerization initiator type Omnirad TPO Omnirad 184 Added amount 4.6% solvent type MEK / methyl acetate ratio 50 / 50 Added amount 50.0%

[0082] (Composition for forming anti-glare layer) The following composition for forming the anti-glare layer is used: ・Active energy line curing resin: LIGHT ACRYLATE PE-3A (manufactured by Kyoei Chemical Co., Ltd., refractive index 1.52) ・Photopolymerization initiator: Omnirad TPO (manufactured by IGM Resins BV, absorption wavelength peak 275nm, 379nm) ・Organic microparticles: Styrene-methyl methacrylate copolymer particles (refractive index 1.515, average particle size 2.0μm) ・Inorganic microparticle 1: Synthetic bentonite ・Inorganic microparticle 2: Alumina nanoparticles, average particle size 40nm ・Solvent: Toluene isopropanol

[0083] (Formation of anti-glare layer) The anti-glare layer forming composition shown in Table 6 is applied to the layer composition in Table 1 on a transparent substrate or a hard coating. The coating is dried in an oven at 80°C for 60 seconds. Then, the coating is hardened by ultraviolet irradiation (Fusion UV Systems Japan KK, light source H bulb) at an irradiation linear intensity of 150 mJ / cm2 to form the anti-glare layer of Table 1 with a hardened film thickness of 5.0 μm.

[0084] [Table 6] Anti-glare layer 1 Active energy line hardening resin type PE-3A ratio 100 Added amount 43.70% Organic microparticles type Styrene-methyl methacrylate copolymer particles Added amount 0.5% Inorganic microparticles type Synthetic bentonite / alumina nanoparticles ratio 20 / 80 Added amount 1.25% Photopolymerization initiator type Omnirad TPO Added amount 4.55% solvent type Toluene / Isopropanol ratio 30 / 70 Added amount 50%

[0085] (Composition for forming a low refractive index layer) The following materials are used as the composition for forming a low refractive index layer: ・Refractive index adjuster: Porous silica microparticle dispersion (average particle size 75 nm, solid content 20%, solvent methyl isobutyl ketone) 8.5 parts by weight ・Antifouling agent: Optool AR-110 (manufactured by Daikin Industries, Ltd., solid content 15%, solvent methyl isobutyl ketone) 5.6 parts by weight ・Active energy line curing resin: Neopentyl terephthalate triacrylate 0.4 parts by weight ・Initiator: Omnirad 184 (manufactured by IGM Resins BV) 0.07 parts by weight ・Leveling agent: RS-77 (manufactured by DIC) 1.7 parts by weight ・Solvent: Methyl isobutyl ketone 83.73 parts by weight

[0086] (Formation of low refractive index layer) The composition for forming a low refractive index layer of the above composition is coated on a hard coating layer or an anti-glare layer, dried in an oven at 80°C for 60 seconds, and then the coating is hardened by irradiation with ultraviolet light using an ultraviolet irradiation device (Fusion UV Systems Japan KK, light source H bulb) with an irradiation linearity of 200mJ / cm2, forming a hardened low refractive index layer with a film thickness of 100nm as shown in Tables 1 and 2.

[0087] [Evaluation of Thin Film Properties] (UV Shielding Rate) The UV shielding rate of the UV shielding layer (UV absorption layer) of the optical thin film is measured. The UV shielding rate of the UV shielding layer (UV absorption layer) formed on the substrate of the optical thin film is measured by peeling off the colored layer with cellophane tape according to the JIS-K5600 adhesion test, so that the UV shielding layer is transferred onto the cellophane tape in a single layer. Furthermore, the UV shielding layer (UV absorption layer) of the optical thin film is a layer in the optical thin film that has the ability to absorb UV light, such as a transparent substrate, hard coating 1, 3 or colored layer 4. The UV shielding layers (UV absorption layers) contained in each optical thin film are shown in Tables 7 and 8. The transmittance of a single layer of the UV shielding layer is measured using an automatic spectrophotometer (manufactured by Hitachi, Ltd., U-4100), and the average transmittance in the UV region (290-400 nm) is calculated. Furthermore, when the UV shielding layer is transferred as a single layer onto celluloid tape, the average transmittance is calculated using the portion of the UV shielding layer without celluloid tape as a reference. Using the obtained average transmittance, the UV shielding rate shown in Equation (2) is calculated. Equation (2): UV shielding rate (%) = 100 - Average transmittance (%) of the UV region (290~400nm)

[0088] (Pencil Hardness Test) The pencil hardness test, conducted according to JIS-K5400-1990, using a pencil (Mitsubishi Pencil Corporation UNI, pencil hardness H) with a 500g load, is performed on the surface of an optical thin film using a Clemen scratch hardness tester (TESTER SANGYO Co., Ltd., HA-301). The appearance change caused by the scratch is visually evaluated. If no scratch is observed, it is recorded as OK; if no scratch is observed, it is recorded as NG.

[0089] (Lightfastness Test) The reliability test of the optical thin film was conducted using a xenon weathering tester (manufactured by Suga Test Instrument Co. Ltd., X75). Under the conditions of xenon lamp illuminance of 60W / cm2 (300~400nm), internal temperature of 45℃ / humidity of 50%RH, a 120-hour damp heat resistance test was performed on each of the obtained optical thin films containing colored layers. Before and after the test, the transmittance was measured using an automatic spectrophotometer (manufactured by Hitachi, Ltd., U-4100). The color difference ΔE*ab of the C light source before and after the test was calculated using the transmittance difference ΔTλ before and after the test, which is the wavelength λ showing the minimum transmittance in the absorption wavelength range of the first to third color materials. A transmittance difference and color difference close to zero are considered good, and ΔE*ab≦5 is considered better.

[0090] [Evaluation of Display Device Characteristics] For the display devices using the obtained optical films 7, 13, 14, and 21-24 in Examples 15-17 and Comparative Examples 11-14 below, the characteristics of the display devices were evaluated by simulation using the following method. In the simulation, the display device was constructed by bonding the optical film to an organic EL display device (object). Furthermore, for the organic EL display device of the object bonded to the optical film, the spectroscopic spectrum is shown in FIG6 when displaying white, and the individual spectra are shown in FIG7 when displaying red, green, and blue. (Transmittance Characteristics (Transmittance Characteristics of White Display)) The transmittance of the obtained optical film was measured using an automatic spectrophotometer (manufactured by Hitachi, Ltd., U-4100). The transmittance of the optical film was multiplied by the individual spectroscopic spectrum of the organic EL display device without optical film mediation in FIG6 when displaying white, and the spectroscopic spectrum after the optical film was transmitted was calculated. The Y-value is calculated by multiplying the individual spectrum of the organic EL display device when displaying white and the spectroscopic spectrum after the optical film has passed through by the relative visual sensitivity. The Y-value obtained from the individual spectrum of the organic EL display device when displaying white is taken as the ratio when it is 100, which is used as the efficiency. This ratio is used as an indicator of the light transmission characteristics of the display device for evaluation.

[0091] (Color Reproduction) The transmittance of the obtained optical film was measured using an automatic spectrophotometer (Hitachi, Ltd., U-4100). The transmittance of the optical film was multiplied by the individual spectra of red, green and blue displays of an organic EL display device without optical film mediation, as shown in Figure 7. The individual chromaticities (x, y) of the red, green and blue monochromatic colors of the CIE (International Commission on Illumination) 1931 color system after the optical film was transmitted were calculated. The triangles obtained by connecting the chromaticities of the obtained red, green, and blue monochromatic colors are then compared with the triangles obtained by connecting the three primary colors of DCI-P3 (red, x=0.680, y=0.320), green, x=0.265, y=0.690, and blue, x=0.150, y=0.060) advocated by DCI (Digital Cinema Initiatives), and the triangles obtained by connecting the three primary colors of Adobe RGB (red, x=0.640, y=0.330), green, x=0.210, y=0.710, and blue, x=0.150, y=0.060) advocated by Adobe Systems (Japanese Patent Application Laid-Open No. 2011-17963). The overlapping area is calculated, and the coverage rate of each specification is determined as an indicator for evaluating color reproduction.

[0092] Regarding the evaluation of the optical film characteristics of optical films 1 to 20 shown in Tables 1 and 2, the results of the ultraviolet shielding layer (ultraviolet absorption layer) ultraviolet shielding rate, pencil hardness, and lightfastness test are shown in Tables 7 and 8.

[0093] [Table 7] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 Optical thin films Optical thin film 1 Optical thin film 2 Optical thin film 3 Optical thin film 4 Optical thin film 5 Optical thin film 6 Optical thin film 7 Optical thin film 8 Optical thin film 9 Optical thin film 10 Optical thin film 11 Optical thin film 12 Optical thin film 13 Optical thin film 14 Ultraviolet rays Absorption layer Substrate TAC Substrate TAC Substrate TAC Substrate TAC Substrate TAC Substrate TAC Substrate TAC substrate PMMA1 Substrate PET1 Substrate PET2 Substrate TAC Substrate TAC Substrate TAC Substrate TAC Ultraviolet rays shading rate 93.0% 93.0% 93.0% 93.0% 93.0% 93.0% 93.0% 93.5% 88.5% 88.8% 93.0% 91.4% 93.0% 93.0% Pencil hardness OK OK OK OK OK OK OK OK OK OK OK OK OK OK Color layer Lightfastness ⊿Tλ 12.8 13.0 12.1 13.2 11.7 9.0 7.4 7.6 8.0 8.1 6.1 9.7 10.1 4.0 ⊿Eab 3.6 3.6 3.3 3.6 3.3 2.8 2.6 2.6 2.7 2.7 1.5 2.3 4.0 0.7

[0094] [Table 8] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Optical thin films Optical thin film 15 Optical thin film 16 Optical thin film 17 Optical thin film 18 Optical thin film 19 Optical thin film 20 UV absorption layer - Color layer 4 substrate PMMA2 Hard coating 3 substrate PMMA2 substrate PMMA2 UV shielding rate - - 19.6% 90.5% 19.6% 19.6% Pencil hardness OK OK OK NG OK OK Color layer Lightfastness ⊿Tλ 65.9 65.4 67.0 13.5 17.8 41.2 ⊿Eab 12.6 12.5 13.0 3.6 5.1 8.0

[0095] The optical films of Examples 1-14 have a colored layer and a transparent substrate with ultraviolet absorption capability disposed above the colored layer. Furthermore, as shown in Tables 7 and 8, the ultraviolet shading rate of the ultraviolet-absorbing layer disposed above the colored layer is 85% or higher. From the results in Tables 7 and 8, it can be seen that in cases such as Comparative Example 1 where the colored layer is disposed above the substrate and there is no ultraviolet shading layer, or in cases such as Comparative Examples 3, 5, and 6 where the substrate does not have ultraviolet absorption function, or in cases such as Comparative Example 2 where the ultraviolet absorption function is disposed within the colored layer, the lightfastness of the colored layer is poor. Compared to these comparative examples, the optical film of the present invention, having a colored layer, can significantly improve the lightfastness of the colored layer by disposing of a transparent substrate with an ultraviolet shading rate of 85% or higher above the colored layer. Furthermore, from the results of Comparative Example 2, it can be seen that even adding an ultraviolet absorber to the colored layer does not significantly improve the lightfastness. Therefore, it can be seen that the UV absorption capacity is less effective when present in the coloring layer, and must be formed as other layers on top. Furthermore, by stacking oxygen barrier layers, including a high molecular weight amine light stabilizer as a free radical scavenger and a nickel dithiocarbamate complex as a singlet oxygen quencher in the coloring layer, the lightfastness can be further improved. Moreover, the results of the lightfastness of the optical film containing coloring layers 2, 3, and 5 show that either the hindered amine light stabilizer or the singlet oxygen quencher can be added, or both can be added.

[0096] In any embodiment, the pencil hardness was determined to be "OK". However, in Comparative Example 4, which has a hard coating 3, the pencil hardness was determined to be "NG". This is believed to be because the absorption wavelength peak of the initiator in the hard coating 3 overlaps with the absorption wavelength of the ultraviolet absorber. The hard coating 1 included in Example 12, although a UV shielding layer formed by an active energy line curing resin containing an ultraviolet absorber, can possess both UV shielding capability and hardness by offsetting the absorption wavelength bands of the ultraviolet absorber and the photopolymerization initiator.

[0097] Regarding the evaluation of the characteristics of display devices 1 to 7 using optical thin films 7, 13, 14 and 21 to 24, the results of simulation of white display light transmission characteristics and color reproduction are shown in Table 9.

[0098] [Table 9] Example 15 Example 16 Example 17 Comparative Example 11 Comparative Example 12 Comparative Example 13 Comparative Example 14 Display device 1 Display device 2 Display device 3 Display device 4 Display device 5 Display device 6 Display device 7 Optical thin films Optical thin film 7 Optical thin film 13 Optical thin film 14 Optical thin film 21 Optical thin film 22 Optical thin film 23 Optical thin film 24 Maximum absorption wavelength (T < 50%) 493nm 800nm 595nm - 493nm 589nm 545nm 575nm Transmittance @ Maximum Absorption Wavelength (T < 50%) 26.3% 11.2% 23.2% - 26.3% 19.5% 48.1% 48.4% White display characteristics evaluation 75 70 77 92 61 75 73 Color reproduction evaluation DCI inclusion rate 92% 91% 90% 88% 94% 88% 89% AdobeRGB inclusion rate 91% 92% 96% 93% 98% 89% 96%

[0099] As can be seen from the results in Table 9, in the display device with the optical thin film having the colored layer of the present invention, the DCI specification coverage is over 90%, and the color reproduction is improved compared to Comparative Example 11 without the colored layer. In particular, in Example 15, which has high absorption in the wavelength band of the first color material, the DCI chromaticity coverage is also greatly improved. Furthermore, in Comparative Example 12, which has deep absorption in multiple wavelength bands of the first and second color materials, the white display transmittance is low. It can be seen that when the colored layer contains multiple color materials, it is preferable that the transmittance is 1% or more and less than 50% at only one maximum absorption wavelength among the maximum absorption wavelengths of each color material. Furthermore, in Comparative Examples 13 and 14, which use color materials whose wavelength range and half-width do not meet the requirements, the color reproduction evaluation is low. In contrast, Examples 15 to 17 exhibit the established color correction function and also show excellent white display transmittance.

[0100] The various embodiments of the present invention have been described in detail above with reference to the drawings. However, the specific configuration is not limited to these embodiments and includes configuration changes and combinations that do not exceed the scope of the present invention. For example, the coloring layer 30 can be formed by a composition for forming a coloring layer containing an active energy line curing resin, a photopolymerization initiator, at least one of the first to third color materials, an additive, and a solvent. In particular, the coloring layer 30 can also be configured such that the active energy line curing resin listed in the composition of the hard coating layer 21 contains a color material. This can improve the scratch resistance of the coloring layer 30 and maintain the color correction function well. Furthermore, the scratch resistance of the object to which the optical film is attached can be further improved.

[0101] For example, by providing other layers in the optical thin film of the present invention, desired functions can be provided. Examples of such other layers include antistatic layers or antifouling layers. [Simplified Explanation of the Diagram]

[0013] Figure 1 is a cross-sectional schematic diagram of the optical thin film 1 according to the first embodiment of the present invention. Figure 2 is a cross-sectional schematic diagram of the optical thin film 1A according to the second embodiment of the present invention. Figure 3 is a cross-sectional schematic diagram of the optical thin film 1B according to the third embodiment of the present invention. Figure 4 is a cross-sectional schematic diagram of the optical thin film 1C according to the fourth embodiment of the present invention. Figure 5 shows the light transmittance spectrum of a transparent substrate. Figure 6 shows the spectrum of a light source used to evaluate light transmittance characteristics. Figure 7 shows the spectrum of a light source used to evaluate color reproduction.

Claims

1. An optical thin film comprising: a sheet-like substrate having an ultraviolet shielding rate of 85% or more according to JIS L 1925; an optical functional layer formed on a first side of the substrate; and a coloring layer formed on a second side of the substrate and containing a pigment; the color difference ΔE*ab before and after a lightfastness test of the optical thin film under conditions of 45°C / 50%RH irradiation with a xenon lamp at a wavelength of 300-400nm and an illuminance of 60W / cm2 for 120 hours satisfies the following formula (1): ΔE*ab≦5 Formula (1); the pigment contained in the coloring layer contains at least one of the following colorants: a first colorant having a maximum absorption wavelength in the range of 470-530nm and a half-width at half-maximum (WHM) of the absorption spectrum of 15-45nm; The second color material has a maximum absorption wavelength in the range of 560–620 nm and a half-width at half-maximum (FWHM) of 15–55 nm; and the third color material has a minimum transmittance wavelength in the range of 650–800 nm within the wavelength range of 400–800 nm; and the transmittance is greater than 1% and less than 50% in any of the absorption wavelength bands of the pigment, 470–530 nm and 560–620 nm.

2. The optical film of claim 1 has a surface hardness of H or higher under a 500g load.

3. The optical thin film of claim 1 or 2, wherein the colored layer contains one or more of a free radical scavenger, a peroxide decomposer, or a singlet oxygen quencher.

4. The optical thin film of claim 3, wherein the free radical scavenger is a hindered amine light stabilizer with a molecular weight of 2000 or higher.

5. The optical thin film of claim 3, wherein the singlet oxygen quencher is a dialkyl phosphate, a dialkyl dithiocarbamate, or a transition metal complex of benzene dithiophenol or a similar dithiophenol.

6. The optical film of claim 1 or 2, wherein the pigment contained in the coloring layer comprises one or more compounds selected from the group consisting of compounds having any one of the following structures: porphyrin, phthalocyanine, azo, cyanine, squaric acid cyanide, coumarin, polyene, quinone, tetra-diporphyrin, pyrromethene, and indigo, and their metal complexes.

7. The optical film of claim 1 or 2, wherein an oxygen barrier layer having an oxygen permeability of less than 10 cc / (m2・day・atm) is further provided between the substrate and the coloring layer, or on the second side of the substrate.

8. The optical thin film of claim 1 or 2, wherein the optical functional layer comprises any of the following antireflective layers: an antireflective layer comprising a high refractive index layer and a low refractive index layer, an antireflective layer comprising a high refractive index layer and an anti-glare layer, an antireflective layer comprising a high refractive index layer, an anti-glare layer and a low refractive index layer, or an antireflective layer comprising an anti-glare layer.

9. The optical film of claim 1 or 2 further comprises an antistatic layer or an antifouling layer.

10. The optical film of claim 8, wherein at least one of the high refractive index layer, the anti-glare layer, or the low refractive index layer further has antistatic properties, and at least one of the high refractive index layer, the anti-glare layer, or the low refractive index layer further has antifouling properties.

11. A display device comprising: a light source; and an optical film as claimed in any one of claims 1 to 10, the optical film being configured such that the second side of the substrate faces the light source.

12. A composition for forming a color layer, comprising an active energy line curing resin, a photopolymerization initiator, a pigment, an additive, and a solvent, wherein the pigment contains at least one of the following color materials: a first color material having a maximum absorption wavelength in the range of 470–530 nm and a half-width at half maximum (WHM) of 15–45 nm; a second color material having a maximum absorption wavelength in the range of 560–620 nm and a WHM of 15–55 nm; and a third color material having a minimum transmittance wavelength in the range of 650–800 nm in the wavelength range of 400–800 nm; and a transmittance of 1% or more and less than 50% in any one of the absorption wavelength bands of 470–530 nm and 560–620 nm; the composition for forming a color layer contains one or more of a free radical scavenger, a peroxide decomposer, or a singlet oxygen quencher as an additive.

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