TW201827899A - Image display apparatus - Google Patents

Abstract

Provided is an image display apparatus that is provided with a light-emitting layer and that is highly efficient regarding light utilization but generates less external light reflection. An image display apparatus according to the present invention is provided with at least: a polarizing plate; a refractive index adjusting layer; and a light-emitting layer in this order, wherein the refractive index of the refractive index adjusting layer is 1.2 or less. According to one embodiment, the light-emitting layer is a layer that emits light by converting the wavelength of a portion of incident light. According to one embodiment, the light-emitting layer includes a quantum dot or a fluorescent body as a wavelength conversion material.

Description

Image display device

The present invention relates to an image display device.

In recent years, an image display device including an illuminating layer composed of a luminescent material such as a quantum dot has been attracting attention as an image display device having excellent color reproducibility. For example, for a quantum dot film using quantum dots, if light is incident, the quantum dots are excited to emit fluorescence. For example, if a backlight of a blue LED (Light Emitting Diode) is used, one part of the blue light is converted into red light and green light by the quantum dot film, and one part of the blue light directly functions as blue light. Exit. As a result, white light can be realized. Further, it is considered that by using such a quantum dot film, NTSC (National Television System Committee) can achieve color reproducibility of 100% or more. On the other hand, in recent years, the image display device has been required to have a high level of improvement in power consumption and reduction in external light reflection, and an image display device including the above-described light-emitting layer is also required to improve light use efficiency. Achieve low power consumption, which in turn requires a reduction in external light reflection. [Prior Art Document] [Patent Document] Patent Document 1: Japanese Patent Laid-Open No. 2015-111518

[Problems to be Solved by the Invention] The present invention has been made in order to solve the above-mentioned problems, and a main object thereof is to provide an image display device which is provided with a light-emitting layer and which has high light utilization efficiency and external light. Less reflection. [Means for Solving the Problem] The image display device of the present invention includes at least a polarizing plate, a refractive index adjusting layer, and a light-emitting layer, and the refractive index adjusting layer has a refractive index of 1.2 or less. In one embodiment, the light-emitting layer is a layer that converts light at a portion of the incident light to emit light. In one embodiment, the luminescent layer comprises a quantum dot or a phosphor as a wavelength converting material. In one embodiment, the light emitting layer is a color filter. In one embodiment, the polarizing plate functions as a circular polarizing plate. In one embodiment, the image display device further includes a colored layer. In one embodiment, the colored layer is disposed between the refractive index adjusting layer and the light emitting layer. According to another aspect of the present invention, an optical laminate comprising a polarizing plate and a refractive index adjusting layer and laminated on an optical member having a light-emitting layer is used. [Effects of the Invention] According to the present invention, it is possible to provide an image display device in which a refractive index adjusting layer is disposed between a polarizing plate and a light-emitting layer, and light utilization efficiency is high, and external light reflection is small.

Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited to the embodiments. (Definition of terms and symbols) The definitions of terms and symbols in this manual are as follows. (1) Refractive index (nx, ny, nz) "nx" is the refractive index in which the refractive index in the plane becomes the largest (ie, the direction of the slow axis), and "ny" is the in-plane and the retarded axis. The refractive index in the direction (ie, the direction of the phase axis), and "nz" is the refractive index in the thickness direction. (2) In-plane phase difference (Re) "Re (λ)" is an in-plane phase difference measured by light having a wavelength of λ nm at 23 °C. For example, "Re(550)" is an in-plane phase difference measured by light having a wavelength of 550 nm at 23 °C. When Re (λ) is used to set the thickness of the layer (film) to d (nm), it is obtained by the formula: Re = (nx - ny) × d. (3) Phase difference in the thickness direction (Rth) "Rth (λ)" is a phase difference in the thickness direction measured by light having a wavelength of λ nm at 23 °C. For example, "Rth(550)" is a phase difference in the thickness direction measured by light having a wavelength of 550 nm at 23 °C. Rth(λ) is obtained by using the formula: Rth=(nx-nz)×d when the thickness of the layer (film) is d (nm). (4) Nz coefficient The Nz coefficient is obtained by using Nz = Rth / Re.A. Overall composition of the image display device Fig. 1 is a schematic cross-sectional view showing an image display device according to an embodiment of the present invention. The image display device 100 includes a polarizing plate 10, a refractive index adjusting layer 20, and a light-emitting layer 30 in this order. Preferably, the polarizing plate 10, the refractive index adjusting layer 20, and the light-emitting layer 30 are arranged in order from the viewing side. In one embodiment, the light-emitting layer is a layer that converts light of a portion of incident light to emit light. In one embodiment, the illuminating layer converts one of the incident blue to blue-violet light into green light and red light, and a part of the light is directly emitted as blue light, thereby utilizing a combination of red light, green light, and blue light. White light. In FIG. 1, as a representative example, a case where the image display device is a liquid crystal display device will be described. In one embodiment, when the image display device is a liquid crystal display device, the liquid crystal display device 100 includes a liquid crystal panel 110 and a backlight 30. The polarizing plate 10, the refractive index adjusting layer 20, and the light emitting layer 30 may be liquid crystal panels. 110 components. Further, the liquid crystal panel 110 may be composed of a liquid crystal cell 40, a viewing-side polarizing plate 10 disposed on both sides of the liquid crystal cell 40, and a back side polarizing plate 50. In this case, the light emitting layer 30 may be included in the liquid crystal panel 40. More specifically, the light-emitting layer 30 can be a color filter provided in the liquid crystal panel 40. Moreover, the polarizing plate 10 can function as a viewing-side polarizing plate of the liquid crystal panel 40. In the present invention, by arranging the refractive index adjusting layer 20 between the polarizing plate 10 and the light-emitting layer 30, the self-emitting layer can be emitted to the light of the refractive index adjusting layer 20 side (for example, including the light-transmitting layer from the backlight 30). The light is reflected on the side of the light-emitting layer 30 of the refractive index adjusting layer 20. The light reflected here can be wavelength converted again by the luminescent layer 30. As a result, the light use efficiency can be improved. Further, when the refractive index adjustment layer is not disposed, most of the light emitted from the light-emitting layer to the side of the polarizing plate passes through the polarizing plate on the side opposite to the light-emitting layer of the polarizing plate (for example, the air interface of the polarizing plate) Produce reflections. In this case, the reflected light is absorbed by the polarizing plate, and it is difficult to reach the light-emitting layer, and the light utilization efficiency is lowered. In the present invention, by arranging the refractive index adjusting layer as described above, absorption of reflected light in the polarizing plate is not generated, and light use efficiency can be improved. Preferably, the image display device 100 is configured such that there is no air layer between the polarizing plate 10 and the refractive index adjusting layer 20 and between the refractive index adjusting layer 20 and the light emitting layer 30. In one embodiment, the polarizing plate 10 and the refractive index adjusting layer 20 are directly laminated. Further, in one embodiment, the refractive index adjusting layer 20 and the light-emitting layer 30 are directly laminated. If the air layer is excluded as described above, external light reflection can be reduced. In the present invention, by appropriately adjusting the refractive index of the refractive index adjusting layer (details are described below), the utilization efficiency of light emitted from the light-emitting layer can be improved, and external light reflection can be suppressed. Further, in the present specification, the term "direct lamination" includes the concept of laminating two members via any appropriate adhesive or adhesive. In one embodiment, the image display device of the present invention may further include a colored layer. Preferably, the colored layer is disposed between the refractive index adjusting layer and the light emitting layer. The colored layer can absorb light of a specific wavelength. When the polarizing plate has a λ/4 plate and functions as a circular polarizing plate (details are described below), the colored layer can be suitably used. A polarizing plate (circular polarizing plate) having a λ/4 plate exhibits an anti-reflection function, and by arranging a colored layer which absorbs light of a specific wavelength, the anti-reflection function of the circular polarizing plate can be improved. Further, by selectively absorbing light of a specific wavelength range by the colored layer, the reflected hue can be appropriately adjusted, and an image display device having a wide color gamut can be obtained. In addition, the light of which wavelength is absorbed by the colored layer can be appropriately selected according to the reflection characteristics of a reflector (for example, an image display panel such as a liquid crystal display panel or an organic EL (Electroluminescence) panel) provided in the image display device. Adjustment. Preferably, there is no air layer between the refractive index adjusting layer and the coloring layer and between the coloring layer and the light emitting layer. In one embodiment, the refractive index adjusting layer and the coloring layer are directly laminated. Further, in one embodiment, the colored layer and the light-emitting layer are directly laminated.B. Polarizer As the polarizing plate, any appropriate polarizing plate can be used. Typically, the polarizing plate is composed of a polarizing element and a protective film disposed on one side or both sides of the polarizing element. B-1. Polarizing element and protective film As the above polarizing element, any appropriate polarizing element can be used. For example, a hydrophilic polymer such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, or an ethylene-vinyl acetate copolymer-based partially saponified film is adsorbed to a dichroic substance such as iodine or a dichroic dye. The film is uniaxially stretched, and a polyene-based alignment film such as a dehydrated material of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride is used. Among these, a polarizing element in which a dichroic substance such as iodine is adsorbed to a polyvinyl alcohol-based film and uniaxially stretched is relatively high in color, and is particularly preferable. The thickness of the polarizing element is preferably from 0.5 μm to 80 μm. A polarizing element in which iodine is adsorbed on a polyvinyl alcohol-based film and uniaxially stretched is typically produced by immersing polyvinyl alcohol in an aqueous solution of iodine to carry out dyeing and extending to the original 3 to 7 times longer. The extension can be carried out after dyeing, and can be extended on one side of the dyeing layer or dyed after stretching. In addition to stretching and dyeing, for example, it is also produced by treatment such as swelling, crosslinking, conditioning, water washing, and drying. For example, by immersing the polyvinyl alcohol-based film in water and dyeing it before washing, not only the dirt or the anti-blocking agent on the surface of the polyvinyl alcohol-based film can be washed, but also the polyvinyl alcohol-based film can be swollen and prevented. Dyeing is uneven. Further, the polyvinyl alcohol-based film may be a film of a single layer (usually a film formed by a film), or may be a polyvinyl alcohol-based resin layer formed by coating on a resin substrate. A technique for producing a polarizing element from a single-layer polyvinyl alcohol-based film is well known in the art. A technique for producing a polarizing element from a polyvinyl alcohol-based resin layer formed by coating on a resin substrate is described, for example, in Japanese Laid-Open Patent Publication No. 2009-098653. The polarizing element preferably exhibits absorption dichroism at any of wavelengths from 380 nm to 780 nm. The single transmittance of the polarizing element is preferably from 40% to 45.5%, more preferably from 42% to 45%. The polarizing element has a degree of polarization of 99.9% or more, preferably 99.95% or more. As the protective film, any appropriate film can be used. Specific examples of the material which is a main component of the film include a cellulose resin such as triethyl cellulose (TAC), or a (meth)acrylic, polyester, polyvinyl alcohol or polycarbonate. Transparent resins such as esters, polyamines, polyimines, polyethers, polyfluorenes, polystyrenes, polypentenes, polyolefins, and acetates. Further, examples thereof include a thermosetting resin such as an acrylic resin, an urethane-based compound, an urethane urethane-based compound, an epoxy-based or a polyfluorene-based resin, and an ultraviolet curable resin. Other than this, for example, a glass-based polymer such as a siloxane-based polymer may be mentioned. Further, a polymer film described in JP-A-2001-343529 (WO01/37007) can also be used. As the material of the film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted quinone group in a side chain, and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in a side chain can be used. Examples of the material include a resin composition comprising an alternating copolymer of isobutylene and N-methylbutyleneimine, and an acrylonitrile-styrene copolymer. The polymer film may be, for example, an extrusion molded product of the above resin composition. Any suitable adhesive layer or adhesive layer can be used in the laminate of the polarizing element and the protective film. The adhesive layer is typically formed of an acrylic adhesive. The subsequent agent layer is typically formed of a polyvinyl alcohol-based adhesive. B-2. Circular Polarizing Plate In one embodiment, the polarizing plate further includes a retardation layer. For example, the polarizing plate functions as a circular polarizing plate by arranging a layer functioning as a λ/4 plate as a phase difference layer. By using a circular polarizing plate, the effect of the image display device of the present invention against external light reflection becomes more remarkable. Fig. 2 is a schematic cross-sectional view showing a circularly polarizing plate according to an embodiment of the present invention. The circularly polarizing plate 10' includes a polarizing element 1 and a retardation layer 2a. The phase difference layer 2a functions as a λ/4 plate. The circularly polarizing plate 10' can be disposed such that the polarizing element 1 is on the viewing side. In one embodiment, the circular polarizing plate 10' is provided with a protective film 3 on the surface of the polarizing element 1 opposite to the retardation layer 2a. The protective film 3 can be omitted depending on the application, the configuration of an image display device having a circular polarizing plate, and the like. Further, the circular polarizing plate may have another protective film (also referred to as an inner protective film, not shown) between the polarizing element and the retardation layer. In the example of the figure, the inner protective film is omitted. In this case, the phase difference layer 2 functions as an inner protective film. According to this configuration, the thickness of the circular polarizing plate can be further reduced. In the present embodiment, the angle between the absorption axis of the polarizing element 1 and the slow phase axis of the phase difference layer 2a is 35° to 55°, preferably 38° to 52°, more preferably 40° to 50°. Further preferably, it is 42° to 48°, and particularly preferably 44° to 46°. If the angle is such a range, the desired circular polarization function can be achieved. Furthermore, in the present specification, when referring to an angle, the angle includes an angle of two directions of clockwise and counterclockwise unless otherwise specified. Fig. 3 is a schematic cross-sectional view showing a circularly polarizing plate according to another embodiment of the present invention. The circular polarizing plate 10'' is disposed between the polarizing element 1 and the retardation layer 2a (λ/4 plate), and further includes another retardation layer 2b. The other retardation layer 2b functions as a λ/2 plate. In the present specification, the phase difference layer 2a (λ/4 plate) may be referred to as a first retardation layer, and the other retardation layer 2b (λ/2 plate) may be referred to as a second. Phase difference layer. The circular polarizing plate 10'' of the illustrated example is provided with a protective film 3 on the side of the polarizing element 1 opposite to the other retardation layer 2b. Further, the circular polarizing plate may have another protective film (also referred to as an inner protective film, not shown) between the polarizing element and the retardation layer. In the example of the figure, the inner protective film is omitted. In this case, the other retardation layer (second retardation layer) 2b can also function as an inner protective film. In the present embodiment, the angle formed by the absorption axis of the polarizing element 1 and the slow axis of the first retardation layer 2a is preferably 65 to 85, more preferably 72 to 78, and still more preferably 75°. Further, the angle formed by the absorption axis of the polarizing element 1 and the retardation axis of the second retardation layer 2b is preferably 10 to 20, more preferably 13 to 17, still more preferably about 15. By arranging two retardation layers at the axial angle as described above, it is possible to obtain a circularly polarizing plate having extremely excellent circularly polarized light characteristics (and, as a result, very excellent antireflection characteristics) in a wide frequency band. B-2-1. First retardation layer (λ/4 plate) The first retardation layer functions as a λ/4 plate as described above. The in-plane retardation Re(550) of the first retardation layer is 100 nm to 180 nm, preferably 110 nm to 170 nm, more preferably 120 nm to 160 nm, and particularly preferably 135 nm to 155 nm. . The first retardation layer typically has a refractive index ellipsoid of nx>ny=nz or nx>ny>nz. Furthermore, in the present specification, for example, "ny=nz" includes not only those that are strictly equal but also substantially equal. In one embodiment, the Nz coefficient of the first retardation layer is, for example, 0.9 to 2, preferably 1 to 1.5, more preferably 1 to 1.3. The thickness of the first retardation layer can be set so that the λ/4 plate functions most appropriately. In other words, the thickness can be set in such a manner that the required in-plane phase difference can be obtained. Specifically, the thickness is preferably from 10 μm to 80 μm, more preferably from 10 μm to 60 μm, and most preferably from 30 μm to 50 μm. The first retardation layer can exhibit an inverse dispersion wavelength characteristic in which the phase difference value is increased according to the wavelength of the measurement light, and can display a positive wavelength dispersion characteristic in which the phase difference value is reduced according to the wavelength of the measurement light, and can also display a phase difference value. A flat wavelength dispersion characteristic that hardly changes depending on the wavelength of the measurement light. In one embodiment, the first retardation layer exhibits a flat wavelength dispersion characteristic. By using the first retardation layer exhibiting flat wavelength dispersion characteristics, excellent anti-reflection characteristics and reflected hue in an oblique direction can be realized. In the present embodiment, Re (450) / Re (550) of the first retardation layer is preferably 0.99 to 1.03, and Re (650) / Re (550) is preferably 0.98 to 1.02. In another embodiment, the first retardation layer exhibits an inverse dispersion wavelength characteristic. By using the first retardation layer exhibiting the inverse dispersion wavelength characteristic, the reflected hue can be increased in the front direction. Further, by using the first retardation layer exhibiting the inverse dispersion wavelength characteristic, it is possible to maintain a practical reflected hue and to improve other characteristics (for example, luminance). In the present embodiment, Re (450) / Re (550) of the first retardation layer is preferably 0.5 or more and less than 1.0, more preferably 0.7 to 0.95. Further, Re (650) / Re (550) of the first retardation layer is preferably more than 1 and 1.2 or less, more preferably 1.01 to 1.15. In the present embodiment, the Nz coefficient of the first retardation layer is preferably from 0.3 to 0.7, more preferably from 0.4 to 0.6, still more preferably from 0.45 to 0.55, still more preferably about 0.5. If the Nz coefficient is in this range, a more excellent reflected hue can be achieved. The λ/4 plate is preferably a stretch film of a polymer film. Specifically, the λ/4 plate can be obtained by appropriately selecting the kind of the polymer, the stretching treatment (for example, the stretching method, the stretching temperature, the stretching ratio, and the stretching direction). As the resin forming the above polymer film, any appropriate resin can be used. Specific examples thereof include a cyclic olefin resin such as polynorthene, a polycarbonate resin, a cellulose resin, a polyvinyl alcohol resin, and a polyfluorene resin. Among them, a decene-based resin or a polycarbonate-based resin is preferable. In addition, the details of the resin which forms a polymer film are described, for example, in Japanese Patent Laid-Open No. 2014-010291. This description is incorporated herein by reference. The poly(pinerene) refers to a (co)polymer obtained by partially or completely using one of the starting materials (monomers) using a norbornene-based monomer having a norbornene ring. Examples of the norbornene-based monomer include norbornene and an alkyl group and/or an alkylene substituent thereof, for example, 5-methyl-2-northene, 5-dimethyl-2-nor Terpene, 5-ethyl-2-northene, 5-butyl-2-northene, 5-ethylidene-2-norbornene, and the like, and polar substituents such as halogen; Pentadiene, 2,3-dihydrodicyclopentadiene, etc.; dimethylene octahydronaphthalene, alkyl and/or alkylene substituents thereof, and polar substituents such as halogen, such as 6-methyl -1,4:5,8-Dimethylene-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-ethyl-1,4:5,8-dimethylene Base-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-ethylene-1,4:5,8-dimethylene-1,4,4a,5,6 , 7,8,8a-octahydronaphthalene, 6-chloro-1,4:5,8-dimethylene-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6- Cyano-1,4:5,8-dimethylene-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-pyridyl-1,4:5,8-di Methylene-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-methoxycarbonyl-1,4:5,8-dimethylene-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, etc.; 3~4 polymer of cyclopentadiene, such as 4,9:5,8-dimethylene-3a, 4,4a, 5,8, 8a,9,9a-octahydro-1H-indole, 4,11:5,10:6,9-trimethylene-3a,4,4a,5,5a,6,9,9a,10,10a , 11, 11a-dodecyl-1H-cyclopentazone and the like. As the polypyrene, various products are commercially available. Specific examples include the product name "Zeonex" manufactured by Japan Zeon Co., Ltd., "Zeonor", the product name "Arton" manufactured by JSR Corporation, the product name "TOPAS" manufactured by TICONA, and the product name manufactured by Mitsui Chemicals Co., Ltd." APEL". As the polycarbonate resin, an aromatic polycarbonate is preferably used. The aromatic polycarbonate is typically obtained by the reaction of a carbonate precursor with an aromatic diphenol compound. Specific examples of the carbonate precursor include carbonium chloride, diphenolic dichloroformate, diphenyl carbonate, di-p-tolyl carbonate, phenyl p-tolyl carbonate, and di-p-chlorophenyl carbonate. , dinaphthyl carbonate and the like. Among these, carbonium chloride and diphenyl carbonate are preferred. Specific examples of the aromatic diphenol compound include 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, and a double (4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxy-3) , 5-dimethylphenyl)butane, 2,2-bis(4-hydroxy-3,5-dipropylphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane or the like. These may be used alone or in combination of two or more. Preferably, 2,2-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3 are used. , 5-trimethylcyclohexane. It is especially preferred to use 2,2-bis(4-hydroxyphenyl)propane and 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane simultaneously. Examples of the stretching method include lateral uniaxial stretching, fixed end biaxial stretching, and sequential biaxial stretching. Specific examples of the biaxial stretching of the fixed end include a method of extending the polymer film in the longitudinal direction while extending in the longitudinal direction. The method can be apparently laterally uniaxially stretched. Also, it can be extended obliquely. By extending obliquely, a long stretched film of the alignment axis (latial phase axis) having a specific angle with respect to the width direction can be obtained. The thickness of the above-mentioned stretched film is typically 5 μm to 80 μm, preferably 15 μm to 60 μm, and more preferably 25 μm to 45 μm. B-2-2. Second retardation layer (λ/2 plate) The second retardation layer functions as a λ/2 plate as described above. The in-plane retardation Re (550) of the second retardation layer is preferably 180 to 300 nm, more preferably 210 to 280 nm, and most preferably 230 to 240 nm. The second retardation layer is typically preferably a refractive index ellipsoid having nx > ny = nz. The Nz coefficient of the second retardation layer is, for example, 0.9 to 2, preferably 1 to 1.5, more preferably 1 to 1.3. The thickness of the second retardation layer can be set so that the λ/2 plate functions most appropriately. In other words, the thickness can be set in such a manner that the required in-plane phase difference can be obtained. Specifically, the thickness is preferably 0.5 μm to 5 μm, more preferably 1 μm to 4 μm, and most preferably 1.5 μm to 3 μm. As the material of the second retardation layer, any suitable material can be employed as long as the above characteristics are obtained. It is preferably a liquid crystal material, and more preferably a liquid crystal material (nematic liquid crystal) in which the liquid crystal phase is a nematic phase. By using a liquid crystal material, the difference between nx and ny of the obtained second retardation layer can be particularly increased as compared with the non-liquid crystal material. As a result, the thickness of the second retardation layer for obtaining the desired in-plane retardation can be exceptionally reduced. As such a liquid crystal material, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The liquid crystal property of the liquid crystal material may be either liquid or thermal. Further, the alignment state of the liquid crystal is preferably horizontal alignment. Further, as the material of the second retardation layer, a resin which forms the above polymer film can be used. The second retardation layer can exhibit an inverse dispersion wavelength characteristic in which the phase difference value is increased according to the wavelength of the measurement light, and can display a positive wavelength dispersion characteristic in which the phase difference value is decreased according to the wavelength of the measurement light, and can also display a phase difference value. A flat wavelength dispersion characteristic that hardly changes depending on the wavelength of the measurement light. It is preferred to exhibit flat wavelength dispersion characteristics. By using a λ/2 plate having a flat wavelength dispersion characteristic, excellent anti-reflection characteristics and a reflected hue in an oblique direction can be achieved. The Re(450)/Re(550) of the retardation layer is preferably 0.99 to 1.03, and Re(650)/Re(550) is preferably 0.98 to 1.02.C. Colored layer The colored layer contains any suitable one or more kinds of colored materials. Typically, in the colored layer, a colored material is present in the matrix. In one embodiment, the colored layer selectively absorbs light of a particular wavelength range (ie, has an absorption maximum wavelength in a particular range of wavelength bands). In another embodiment, the colored layer functions to absorb all wavelengths in the visible light region. Preferably, the colored layer selectively absorbs light of a particular wavelength range. When the coloring layer is formed by selectively absorbing light of a specific wavelength range, the decrease in visible light transmittance (that is, the decrease in luminance) can be suppressed, and the antireflection function of the circularly polarizing plate can be improved. Further, by adjusting the wavelength of the absorbed light, the reflected hue can be made neutral, and unnecessary coloring can be prevented. In one embodiment, the colored layer has an absorption maximum wavelength in a wavelength band of 440 nm to 510 nm. When such a coloring layer is formed, the reflected hue can be appropriately adjusted. In another embodiment, the colored layer has an absorption maximum wavelength in a wavelength band ranging from 560 nm to 610 nm. When such a coloring layer is formed, the reflected hue can be appropriately adjusted. Further, in another embodiment, the colored layer has an absorption maximum wavelength in a wavelength band of 440 nm to 510 nm and 560 nm to 610 nm. According to this configuration, the image display device can be significantly broadly colored. As described above, the coloring layer having two or more absorption maximum wavelengths can be obtained by using a plurality of colored materials. The transmittance of the colored layer at the absorption maximum wavelength is preferably from 0% to 80%, more preferably from 0% to 70%. If it is such a range, the above effects of the present invention become more remarkable. The visible light transmittance of the colored layer is preferably from 30% to 90%, more preferably from 30% to 80%. If it is such a range, the fall of brightness can be suppressed, and the anti-reflection function of a circular polarizer can be improved. The haze value of the colored layer is preferably 15% or less, more preferably 10% or less. By controlling the haze value of the colored layer within such a range, it is possible to prevent the depolarized light that has passed through the phase difference layer from being polarized, and as a result, the antireflection function of the circularly polarizing plate can be effectively exhibited. The smaller the haze value of the colored layer, the better, and the lower limit is, for example, 0.1%. The thickness of the colored layer is preferably from 1 μm to 100 μm, more preferably from 2 μm to 30 μm. (Colorful material) Specific examples of the above-mentioned colored material include an anthraquinone type, a triphenylmethane type, a naphthoquinone type, a thioindigo type, a purple ring ketone type, an anthraquinone type, a squaraine type, a cyanine system, and an anthraquinone. Aromatic, azaporphyrin, phthalocyanine, phthalocyanine, anthraquinone, polymethine, rosin, oxonium, lanthanide, azo, anthraquinone, methine azo, quinacridone, diterpene, pyrrolopyrroledione, anthrapyridone, isoindolinone, indanthrene, indigo, thioindigo A dye such as a quinacridone, a quinoline or a triphenylmethane. In one embodiment, as the colored material, a lanthanoid, an anthraquinone, a naphthoquinone, an anthraquinone, an oxonium, an azo, or an anthracene can be used.A dye of the system or phthalocyanine. When these dyes are used, a coloring layer having an absorption maximum wavelength in a wavelength band of 440 nm to 510 nm can be formed. In one embodiment, as the colored material, a coloring layer having an absorption maximum wavelength in the above range can be, for example, an indigo-based, rosin-based, quinacridone-based or porphyrin-based dye as a colored material. When these dyes are used, a coloring layer having an absorption maximum wavelength in a wavelength band of 560 nm to 610 nm can be formed. Further, as the colored material, a pigment can also be used. Specific examples of the pigment include black pigment (carbon black, bone black, graphite, iron black, titanium black, etc.), azo pigment, phthalocyanine pigment, and polycyclic pigment (quinacridone). Lanthanide, purple ketone, isoindolinone, isoporphyrin, diterpene, thioindigo, lanthanide, quinophthalone, metal complex, pyrrolopyrroledione , etc.), dye lake pigments, white extender pigments (titanium oxide, zinc oxide, zinc sulfide, clay, talc, barium sulfate, calcium carbonate, etc.), color pigments (chrome yellow, cadmium, molybdenum cadmium, nickel titanium , chrome-titanium, iron oxide yellow, iron oxide, zinc chromate, lead dan, ultramarine blue, iron blue, cobalt blue, chrome green, chromium oxide, bismuth vanadate, etc.), luster pigments (pearl pigments, aluminum pigments, bronze pigments) Etc.), fluorescent pigments (zinc sulfide, barium sulfide, barium aluminate, etc.). The content ratio of the above colored material can be set to any appropriate ratio depending on the type of the colored material, the desired light absorption characteristics, and the like. The content ratio of the above colored material is, for example, 0.01 parts by weight to 100 parts by weight, more preferably 0.01 parts by weight to 50 parts by weight, per 100 parts by weight of the base material. In the case where a pigment is used as the colored material, the number average particle diameter of the pigment in the matrix is preferably 500 nm or less, more preferably 1 nm to 100 nm. If it is such a range, the coloring layer with a small haze value can be formed. The number average particle diameter of the pigment was measured and measured by the cross-sectional observation of the colored layer. (Matrix) The substrate may be an adhesive or a resin film. It is preferably an adhesive. When the substrate is an adhesive, any suitable adhesive can be used as the adhesive. The adhesive preferably has transparency and optical isotropy. Specific examples of the adhesive include a rubber-based adhesive, an acrylic adhesive, a polyoxygen-based adhesive, an epoxy-based adhesive, and a cellulose-based adhesive. A rubber-based adhesive or an acrylic adhesive is preferred. The rubber-based polymer of the rubber-based adhesive (adhesive composition) is a polymer exhibiting rubber elasticity in a temperature region near room temperature. Preferred examples of the rubber-based polymer (A) include a styrene-based thermoplastic elastomer (A1), an isobutylene-based polymer (A2), and a combination thereof. Examples of the styrene-based thermoplastic elastomer (A1) include styrene-ethylene-butylene-styrene block copolymer (SEBS) and styrene-isoprene-styrene block copolymer (SIS). , styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene-propylene-styrene block copolymer (SEPS, SIS hydride), styrene-ethylene-propylene block copolymer (SEP, hydride of styrene-isoprene block copolymer), styrene block such as styrene-isobutylene-styrene block copolymer (SIBS), styrene-butadiene rubber (SBR) Copolymer. Among these, a styrene-ethylene-propylene-styrene block copolymer is preferred in that it has a polystyrene block at both ends of the molecule and has a higher cohesive force as a polymer. SEPS, hydride of SIS), styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-isobutylene-styrene block copolymer (SIBS). A commercially available product can be used as the styrene thermoplastic elastomer (A1). Specific examples of the commercial product include SEPTON manufactured by Kuraray Co., Ltd., HYBRAR, TUFTEC manufactured by Asahi Kasei Chemical Co., Ltd., and SIBSTAR manufactured by KANEKA Co., Ltd. The weight average molecular weight of the styrene-based thermoplastic elastomer (A1) is preferably from 50,000 to 500,000, more preferably from 50,000 to 300,000, and still more preferably from 50,000 to 250,000. When the weight average molecular weight of the styrene-based thermoplastic elastomer (A1) is in this range, the cohesive force and viscoelasticity of the polymer can be achieved, which is preferable. The styrene content in the styrene-based thermoplastic elastomer (A1) is preferably from about 5% by weight to about 70% by weight, more preferably from about 5% by weight to about 40% by weight, still more preferably from about 10% by weight to about 20% by weight. . When the styrene content in the styrene-based thermoplastic elastomer (A1) is in this range, it is preferable to maintain the cohesive force based on the styrene portion and to secure the viscoelasticity based on the soft segment. The isobutylene polymer (A2) includes isobutylene as a constituent monomer, and the weight average molecular weight (Mw) is preferably 500,000 or more. The isobutylene polymer (A2) may be a homopolymer of isobutylene (polyisobutylene, PIB) or a copolymer of isobutylene as a main monomer (ie, isobutylene may be copolymerized at a ratio of more than 50 mol%). Copolymer). Examples of such a copolymer include a copolymer of isobutylene and n-butene, and a copolymer of isobutylene and isoprene (for example, ordinary butyl rubber, chlorobutyl rubber, bromobutyl rubber, and partially crosslinked). A butyl rubber such as butyl rubber), a sulfide or a modified product thereof (for example, modified by a functional group such as a hydroxyl group, a carboxyl group, an amine group or an epoxy group). Among these, polyisobutylene (PIB) is preferred in that the main chain does not contain a double bond and is excellent in weather resistance. A commercially available product can be used as the isobutylene polymer (A2). Specific examples of the commercially available product include OPPANOL manufactured by BASF Corporation. The weight average molecular weight (Mw) of the isobutylene polymer (A2) is preferably 500,000 or more, more preferably 600,000 or more, still more preferably 700,000 or more. Further, the upper limit of the weight average molecular weight (Mw) is preferably 5,000,000 or less, more preferably 3,000,000 or less, still more preferably 2,000,000 or less. By setting the weight average molecular weight of the isobutylene polymer (A2) to 500,000 or more, it is possible to obtain an adhesive composition which is more excellent in durability during storage at a high temperature. The content of the rubber-based polymer (A) in the adhesive (adhesive composition) is preferably 30% by weight or more, more preferably 40% by weight or more, based on the total solid content of the adhesive composition. It is preferably 50% by weight or more, and particularly preferably 60% by weight or more. The upper limit of the content of the rubber-based polymer is preferably 95% by weight or less, more preferably 90% by weight or less. In the rubber-based adhesive, the rubber-based polymer (A) can be used in combination with other rubber-based polymers. Specific examples of the other rubber-based polymer include butyl rubber (IIR), butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), and EPR (binary ethylene-propylene rubber). EPT (ternary ethylene-propylene rubber), acrylic rubber, urethane rubber, polyurethane thermoplastic elastomer; polyester thermoplastic elastomer; polypropylene and EPT (ternary ethylene) A blend of a polymer blend or the like of propylene rubber) is a thermoplastic elastomer. The blending amount of the other rubber-based polymer is preferably about 10 parts by weight or less based on 100 parts by weight of the rubber-based polymer (A). The acrylic polymer of the acrylic adhesive (adhesive composition) typically contains an alkyl (meth)acrylate as a main component, and may contain an aromatic ring as a copolymer component corresponding to the purpose. Acrylate, guanamine containing monomer, carboxyl containing monomer and/or hydroxyl containing monomer. In the present specification, the term "(meth)acrylate" means acrylate and/or methacrylate. The alkyl (meth)acrylate may, for example, be a linear or branched alkyl group having 1 to 18 carbon atoms. The (meth) acrylate containing an aromatic ring is a compound containing an aromatic ring structure in its structure and containing a (meth) acrylonitrile group. The aromatic ring may, for example, be a benzene ring, a naphthalene ring or a biphenyl ring. The (meth) acrylate containing an aromatic ring satisfies durability (especially for the durability of the transparent conductive layer) and improves display unevenness caused by discoloration of the peripheral portion. A monoamine-containing system comprising a guanamine group in its structure and a compound containing a polymerizable unsaturated double bond such as a (meth) acrylonitrile group or a vinyl group. The single system containing a carboxyl group contains a carboxyl group and a compound containing a polymerizable unsaturated double bond such as a (meth)acryl fluorenyl group or a vinyl group. The hydroxyl group-containing single system contains a hydroxyl group in its structure, and contains a compound of a polymerizable unsaturated double bond such as a (meth)acryl fluorenyl group or a vinyl group. The details of the acrylic adhesive are described, for example, in Japanese Laid-Open Patent Publication No. 2015-199942, the disclosure of which is incorporated herein by reference. When the substrate is a resin film, any suitable resin can be used as the resin constituting the resin film. Specifically, the resin may be a thermoplastic resin, may be a thermosetting resin, or may be an active energy ray-curable resin. Examples of the active energy ray-curable resin include an electron beam curable resin, an ultraviolet curable resin, and a visible light curable resin. Specific examples of the resin include an epoxy resin, a (meth) acrylate (for example, methyl methacrylate, butyl acrylate), norbornene, polyethylene, poly(vinyl butyral), and poly(vinyl acetate). Ester), polyurea, polyurethane, amine polyoxymethane (AMS), polyphenylmethyl oxa oxide, polyphenylalkyl siloxane, polydiphenyl siloxane, poly Alkyl oxane, sesquiterpene oxide, fluorinated polyfluorene oxide, polyoxynium substituted by vinyl and hydride, styrenic polymer (eg polystyrene, amine polystyrene (APS), Poly(acrylonitrile vinyl styrene) (AES), a polymer obtained by crosslinking with a difunctional monomer (for example, divinylbenzene), a polyester polymer (for example, polyethylene terephthalate), Cellulose-based polymer (for example, triacetyl cellulose), vinyl chloride polymer, guanamine polymer, quinone-based polymer, vinyl alcohol polymer, epoxy polymer, polyoxyl polymerization Amino acid acrylate polymer. These may be used singly or in combination (for example, blending, copolymerization). These resins may be subjected to treatment such as stretching, heating, pressurization, etc. after forming a film. It is preferably a thermosetting resin or an ultraviolet curable resin, more preferably a thermosetting resin. The reason for this is that it can be suitably applied when the optical member of the present invention is produced by roll-to-roll.D. Refractive index adjustment layer The refractive index adjusting layer has a refractive index of 1.2 or less, preferably 1.15 or less, more preferably 1.01 to 1.1. If it is such a range, the utilization efficiency of the light emitted from the light-emitting layer can be improved, and external light reflection can be suppressed. The refractive index adjusting layer typically has a void inside. The void ratio of the refractive index adjusting layer may take any appropriate value. The void ratio is, for example, 5% to 99%, preferably 25% to 95%. When the void ratio is within the above range, the refractive index of the refractive index adjusting layer can be sufficiently lowered, and high mechanical strength can be obtained. The refractive index adjusting layer having a void inside may have, for example, a structure having at least one of a particle shape, a fiber shape, and a flat shape. The structure in which the particles are formed (constituting unit) may be solid particles or hollow particles, and specific examples thereof include polyfluorene oxide particles or polycrystalline oxygen particles having fine pores, hollow cerium oxide nanoparticles or dioxide.矽 hollow nanosphere and so on. The fibrous constituent unit is, for example, a nanofiber having a diameter of a nanometer, and specific examples thereof include cellulose nanofibers and alumina nanofibers. For example, a nano-sized bentonite (for example, Kunipia F [trade name]) can be mentioned. Further, in the void structure of the present invention, a single constituent unit which forms the fine void structure or a portion in which one or a plurality of constituent units are bonded to each other by a catalyst, for example, chemically bonded directly or indirectly, is included. In the present invention, the term "indirectly bonded" to each other means that the constituent units are bonded to each other via a small amount of the binder component of the constituent unit amount or less. The term "directly bonded" to each other means that the constituent units are directly bonded to each other without passing through a binder component or the like. As the material constituting the refractive index adjusting layer, any appropriate material can be employed. As the above-mentioned materials, for example, materials described in International Publication No. 2004/113966, Japanese Patent Laid-Open Publication No. 2013-254183, and Japanese Patent Laid-Open No. 2012-189802 can be used. Specific examples thereof include a cerium oxide compound; a hydrolyzable decane, and a partial hydrolyzate and a dehydrated condensate thereof; an organic polymer; a hydrazine compound containing a stanol group; Active cerium oxide obtained by contacting ion exchange resin; polymerizable monomer (for example, (meth)acrylic monomer and styrene monomer); curable resin (for example, (meth)acrylic resin, fluorine-containing Resin, and urethane resin); and combinations of these. Examples of the organic polymer include polyolefins (for example, polyethylene and polypropylene), polyurethanes, and fluorine-containing polymers (for example, fluorine-containing monomer units are used to impart crosslinking. a fluorocopolymer as a constituent component of a reactive component, or a polyester (for example, a poly(meth)acrylic acid derivative (in the present specification, the term "(meth)acrylic acid means acrylic acid and methacrylic acid," ( Methyl)" is used in this sense), polyethers, polyamines, polyimides, polyureas, and polycarbonates. The above material preferably contains a cerium oxide compound; a hydrolyzable decane, and a partial hydrolyzate thereof and a dehydrated condensate. As the above-mentioned cerium oxide-based compound, for example, SiO is mentioned.₂ (phthalic anhydride); containing SiO₂ Selected from Na₂ O-B₂ O₃ (boronic acid), Al₂ O₃ (alumina), B₂ O₃ TiO₂ ZrO₂ , SnO₂ Ce₂ O₃ , P₂ O₅ , Sb₂ O₃ MoO₃ ZnO₂ , WO₃ TiO₂ -Al₂ O₃ TiO₂ -ZrO₂ In₂ O₃ -SnO₂ And Sb₂ O₃ -SnO₂ A compound of at least one compound of the group (the "-" is represented by a composite oxide). Examples of the hydrolyzable decanes include hydrolyzable decanes containing an alkyl group which may have a substituent (for example, fluorine). The hydrolyzable decane, and a partial hydrolyzate and a dehydrated condensate thereof are preferably alkoxy decane and sesquiterpene oxide. The alkoxydecane may be a monomer or an oligomer. The alkoxydecane monomer preferably has three or more alkoxy groups. Examples of the alkoxydecane monomer include methyltrimethoxydecane, methyltriethoxydecane, phenyltriethoxydecane, tetramethoxydecane, tetraethoxydecane, and tetrabutoxy Alkane, tetrapropoxydecane, diethoxydimethoxydecane, dimethyldimethoxydecane, and dimethyldiethoxydecane. The alkoxydecane oligomer is preferably a polycondensate obtained by hydrolysis and polycondensation of the above monomers. By using an alkoxydecane as the above material, a refractive index adjusting layer having excellent uniformity can be obtained. Sesquiterpene oxide from the general formula RSiO_1.5 A general term for a network of polyoxyalkylenes (wherein R represents an organofunctional group). Examples of R include an alkyl group (which may be a straight chain or a branched chain having a carbon number of 1 to 6), a phenyl group, and an alkoxy group (for example, a methoxy group and an ethoxy group). Examples of the structure of the sesquiterpene oxide include a ladder type and a cage type. By using sesquiterpene oxide as the above material, a refractive index adjusting layer having excellent uniformity, weather resistance, transparency, and hardness can be obtained. As the above particles, any appropriate particles can be employed. The above particles typically comprise a cerium oxide compound. The shape of the cerium oxide particles can be confirmed, for example, by observation using a transmission electron microscope. The average particle diameter of the above particles is, for example, 5 nm to 200 nm, preferably 10 nm to 200 nm. According to the above configuration, the refractive index adjusting layer having a sufficiently low refractive index can be obtained, and the transparency of the refractive index adjusting layer can be maintained. In addition, in the present specification, the average particle diameter refers to a specific surface area (m) measured by a nitrogen adsorption method (BET method).² /g), and the value obtained by the formula of the average particle diameter = (2720 / specific surface area) (refer to Japanese Patent Laid-Open No. Hei 1-317115). Examples of the method of obtaining the refractive index adjusting layer include, for example, JP-A-2010-189212, JP-A-2008-040171, JP-A-2006-011175, and WO 2004/113966. And the methods described in the references. Specifically, a method of hydrolyzing and polycondensing at least one of a cerium oxide-based compound, a hydrolyzable decane, and a partial hydrolyzate and a dehydrated condensate thereof; and using porous particles and/or hollow microparticles a method of producing an aerogel layer by using a rebound phenomenon; using a gel obtained by sol gel pulverization, and chemically combining microporous particles in the pulverized liquid with a catalyst or the like A method of pulverizing a gel or the like. However, the refractive index adjusting layer is not limited to this manufacturing method, and can be produced by any manufacturing method. The refractive index adjusting layer is bonded to the light-emitting layer and the polarizing plate via any appropriate adhesive layer (for example, an adhesive layer or an adhesive layer, not shown). In the case where the refractive index adjusting layer contains an adhesive, the adhesive layer may be omitted. The haze of the refractive index adjusting layer is, for example, 0.1% to 30%, preferably 0.2% to 10%. The mechanical strength of the refractive index adjusting layer is preferably, for example, 60% to 100% by the BEMCOT (registered trademark). The gripping force between the refractive index adjusting layer and the light-emitting layer is not particularly limited, and is, for example, 0.01 N/25 mm or more, preferably 0.1 N/25 mm or more, and more preferably 1 N/25 mm or more. Further, in order to increase the mechanical strength or the gripping force, the primer treatment, the heat treatment, the humidification treatment, and the step of before and after the formation of the coating film or before and after the bonding of any appropriate adhesive layer or other member may be performed. UV treatment, corona treatment, plasma treatment, etc. The thickness of the refractive index adjusting layer is preferably from 100 nm to 5000 nm, more preferably from 200 nm to 4000 nm, further preferably from 300 nm to 3000 nm, and particularly preferably from 500 nm to 2000 nm. In the case of such a range, the light in the visible light region sufficiently exhibits an optical function, and a refractive index adjusting layer having excellent durability can be realized.E. Luminous layer The luminescent layer typically comprises a wavelength converting material. In more detail, the light-emitting layer may comprise a matrix and a wavelength converting material dispersed in the matrix. E-1. Substrate As the material constituting the substrate (hereinafter, also referred to as a matrix material), any appropriate material can be used. Examples of such a material include a resin, an organic oxide, and an inorganic oxide. The matrix material preferably has low oxygen permeability and moisture permeability, high light stability and chemical stability, has a specific refractive index, has excellent transparency, and/or has excellent dispersion for wavelength conversion materials. Sex. The substrate may practically comprise a resin film or an adhesive. E-1-1. Resin film When the substrate is a resin film, any suitable resin can be used as the resin constituting the resin film. Specifically, the resin may be a thermoplastic resin, may be a thermosetting resin, or may be an active energy ray-curable resin. Examples of the active energy ray-curable resin include an electron beam curable resin, an ultraviolet curable resin, and a visible light curable resin. Specific examples of the resin include an epoxy resin, a (meth) acrylate (for example, methyl methacrylate, butyl acrylate), norbornene, polyethylene, poly(vinyl butyral), and poly(vinyl acetate). Ester), polyurea, polyurethane, amine polyoxymethane (AMS), polyphenylmethyl oxa oxide, polyphenylalkyl siloxane, polydiphenyl siloxane, poly Alkyl oxane, sesquiterpene oxide, fluorinated polyfluorene oxide, polyoxynium substituted by vinyl and hydride, styrenic polymer (eg polystyrene, amine polystyrene (APS), Poly(acrylonitrile vinyl styrene) (AES), a polymer obtained by crosslinking with a difunctional monomer (for example, divinylbenzene), a polyester polymer (for example, polyethylene terephthalate), Cellulose-based polymer (for example, triacetyl cellulose), vinyl chloride polymer, guanamine polymer, quinone-based polymer, vinyl alcohol polymer, epoxy polymer, polyoxyl polymerization Amino acid acrylate polymer. These may be used singly or in combination (for example, blending, copolymerization). These resins may be subjected to treatment such as stretching, heating, pressurization, etc. after forming a film. It is preferably a thermosetting resin or an ultraviolet curable resin, more preferably a thermosetting resin. E-1-2. Adhesive When the substrate is an adhesive, any suitable adhesive can be used as the adhesive. The adhesive preferably has transparency and optical isotropy. Specific examples of the adhesive include a rubber-based adhesive, an acrylic adhesive, a polyoxygen-based adhesive, an epoxy-based adhesive, and a cellulose-based adhesive. A rubber-based adhesive or an acrylic adhesive is preferred. E-2. Wavelength Conversion Material The wavelength conversion material controls the wavelength conversion characteristics of the light-emitting layer. The wavelength converting material may be, for example, a quantum dot or a phosphor. The content of the wavelength converting material in the light-emitting layer (the total amount when two or more kinds are used) is preferably 0.01 with respect to 100 parts by weight of the matrix material (typically a resin or an adhesive solid content). The parts by weight are -50 parts by weight, more preferably 0.01 parts by weight to 30 parts by weight. When the content of the wavelength converting material is within such a range, an image display device excellent in hue balance of all of RGB (Red Green Blue) can be realized. E-2-1. Quantum Dots The center wavelength of the quantum dot can be adjusted by the material and/or composition of the quantum dot, particle size, shape, and the like. Quantum dots can comprise any suitable material. The quantum dots preferably comprise an inorganic material, more preferably an inorganic conductor material or an inorganic semiconductor material. Examples of the semiconductor material include semiconductors of Groups II-VI, III-V, IV-VI, and Group IV. Specific examples include Si, Ge, Sn, Se, Te, B, and C (including diamond), P, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, and InN. , InP, InAs, InSb, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdSeZn, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, GeTe, SnS, SnSe, SnTe , PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si₃ N₄ Ge₃ N₄ Al₂ O₃ , (Al, Ga, In)₂ (S, Se, Te)₃ Al₂ CO. These may be used alone or in combination of two or more. The quantum dots may contain a p-type dopant or an n-type dopant. Also, the quantum dots may have a core-shell structure. In the core-shell structure, any suitable functional layer (single layer or plural layer) may be formed around the shell depending on the purpose, and the surface of the shell may be surface-treated and/or chemically modified. As the shape of the quantum dot, any appropriate shape can be adopted depending on the purpose. Specific examples include a true spherical shape, a scaly shape, a plate shape, an elliptical shape, and an amorphous shape. The size of the quantum dots can be any suitable size depending on the desired wavelength of illumination. The size of the quantum dots is preferably from 1 nm to 10 nm, more preferably from 2 nm to 8 nm. If the size of the quantum dot is such a range, green and red respectively show vivid light, and high color rendering can be achieved. For example, green light can be illuminated at a quantum dot size of about 7 nm, and red light can be illuminated at about 3 nm. Further, the size of the quantum dot is an average particle diameter when the quantum dot is, for example, a true spherical shape, and is a size corresponding to the smallest axis of the shape in the case of a shape other than the quantum dot. The details of the quantum dots are described, for example, in JP-A-2012-169271, JP-A-2015-102857, JP-A-2015-65158, JP-A-2013-544018, and Japan. In the specification of the Japanese Patent Application Publication No. 2010-533976, the disclosure of each of the publications is incorporated herein by reference. Commercially available products can be used for the quantum dots. E-2-2. Phosphor As a phosphor, any suitable phosphor that emits light of a desired color can be used depending on the purpose. Specific examples include a red phosphor and a green phosphor. As the red phosphor, for example, Mn can be cited.⁴⁺ Activated composite fluoride phosphor. The complex fluoride fluorescent system means that at least one coordination center (for example, M below) is surrounded by fluoride ions functioning as a ligand, and a counter ion (for example, A below) is used to compensate a charge as needed. Coordination compound. As a specific example, a₂ [MF₅ ]:Mn⁴⁺ , A₃ [MF₆ ]:Mn⁴⁺ Zn₂ [MF₇ ]:Mn⁴⁺ , A[In₂ F₇ ]:Mn⁴⁺ , A₂ [M'F₆ ]:Mn⁴⁺ , E[M'F₆ ]:Mn⁴⁺ , A₃ [ZrF₇ ]:Mn⁴⁺ Ba_0.65 Zr_0.35 F_2.70 :Mn⁴⁺ . Here, A is Li, Na, K, Rb, Cs, NH₄ Or a combination thereof. M is Al, Ga, In, or a combination thereof. M' is Ge, Si, Sn, Ti, Zr or a combination thereof. E is Mg, Ca, Sr, Ba, Zn or a combination thereof. A complex fluoride phosphor having a coordination number of 6 in the coordination center is preferred. The details of such a red phosphor are described, for example, in Japanese Laid-Open Patent Publication No. 2015-84327. The entire disclosure of this publication is incorporated herein by reference. As the green phosphor, for example, it is possible to include β-type Si.₃ N₄ A compound in which a solid solution of a crystalline structure of Sialon is used as a main component. It is preferred to carry out a treatment in which the amount of oxygen contained in the crystal of the sialon is set to a specific amount (for example, 0.8% by mass) or less. By performing such a treatment, a green phosphor that emits bright light with a narrow peak width can be obtained. The details of such a green phosphor are described, for example, in Japanese Laid-Open Patent Publication No. 2013-28814. The entire disclosure of this publication is incorporated herein by reference. The light emitting layer may be a single layer or may have a laminated structure. In the case where the light-emitting layer has a laminated structure, each layer may typically include a wavelength converting material having different light-emitting characteristics. The thickness of the light-emitting layer (the total thickness thereof in the case of a laminated structure) is preferably from 1 μm to 500 μm, more preferably from 100 μm to 400 μm. When the thickness of the light-emitting layer is in this range, the conversion efficiency and durability can be excellent. The thickness of each layer in the case where the light-emitting layer has a laminated structure is preferably from 1 μm to 300 μm, more preferably from 10 μm to 250 μm. The visible light reflectance of the light-emitting layer is preferably 20% or more, more preferably 25% or more. In the present invention, by providing the refractive index adjusting layer, even if a light-emitting layer having a high reflectance is used, an image display device having less external light reflection can be obtained. The upper limit of the visible light reflectance is, for example, 90%.F. Other components F-1. Backlight As the light source included in the backlight, for example, a cold cathode tube light source (CCFL), an LED light source, or the like can be given. In one embodiment, the backlight includes an LED light source. When an LED light source is used, an image display device having excellent viewing angle characteristics can be obtained. In one embodiment, a light source that emits blue light (preferably an LED light source) can be used. The backlight may be in a direct type or an edge illumination. In addition to the light source, the backlight may further include other members such as a light guide plate, a diffusion plate, and a cymbal sheet as needed. F-2. Liquid crystal panel The liquid crystal panel 110 is typically provided with a liquid crystal cell 40, a polarizing plate (viewing side polarizing plate) 10 disposed on the viewing side of the liquid crystal cell 40, and a liquid crystal cell disposed as shown in FIG. The back side polarizing plate 50 on the back side. In one embodiment, the polarizing plate (viewing side polarizing plate) 10 and the back side polarizing plate 50 may be disposed such that their absorption axes are substantially orthogonal or parallel. The liquid crystal cell 40 has a pair of substrates 41 and 41' and a liquid crystal layer 42 as a display medium sandwiched between the substrates. In a typical configuration, a color filter (light-emitting layer 30) and a black matrix are disposed on one substrate 41, and a switching element for controlling electro-optic characteristics of the liquid crystal is provided on the other substrate 41', and a gate signal is provided to the switching element. A scan line and a signal line, a pixel electrode, and a counter electrode that provide a source signal. The interval (cell gap) of the above substrates can be controlled by a spacer or the like. An alignment film containing polyimine or the like may be provided on the side of the substrate in contact with the liquid crystal layer, for example. In one embodiment, the liquid crystal layer includes liquid crystal molecules aligned in a vertical alignment in the absence of an electric field. Such a liquid crystal layer (resulting in a liquid crystal cell) typically exhibits a three-dimensional refractive index of nz > nx = ny. As a driving mode for liquid crystal molecules aligned in a vertical alignment in the absence of an electric field, for example, a vertical alignment (VA) mode can be cited. The VA mode includes a multi-domain VA (MVA) mode. In another embodiment, the liquid crystal layer includes liquid crystal molecules aligned in a surface in a state where no electric field exists. Such a liquid crystal layer (resulting in a liquid crystal cell) typically exhibits a three-dimensional refractive index of nx > ny = nz. Furthermore, in the present specification, the term "ny=nz" includes not only the case where ny and nz are completely the same, but also the case where ny and nz are substantially the same. A typical example of a driving mode in which a liquid crystal layer exhibiting such a three-dimensional refractive index is used is a lateral electric field effect (IPS) mode, a fringe electric field switching (FFS) mode, and the like. Furthermore, the IPS mode described above includes a super transverse electric field effect (S-IPS) mode or an advanced super transverse electric field effect (AS-IPS) mode using a V-shaped electrode or a zigzag electrode. Further, the FFS mode includes an advanced edge electric field switching (A-FFS) mode or a super fringe electric field switching (U-FFS) mode using a V-shaped electrode or a zigzag electrode. As the back side polarizing plate, any appropriate polarizing plate can be used.G. Optical laminate According to another aspect of the present invention, an optical laminate is provided. The optical laminate includes a polarizing plate and a refractive index adjusting layer. As the polarizing plate, the polarizing plate described in the above item B can be used. The polarizing plate may be a polarizing plate that functions as a circular polarizing plate as described in the item B. As the refractive index adjusting layer, the refractive index adjusting layer described in the above item D can be used. The optical laminate of the present invention can be laminated and bonded to an optical member having a light-emitting layer. As the light-emitting layer, a layer which can convert a part of the wavelength of the incident light and emit light can be used. Specifically, the light-emitting layer described in the above item E can be used. The optical laminate of the present invention can be used by being bonded to a light-emitting layer via any appropriate adhesive or adhesive. In one embodiment, the optical layered body may further include a colored layer. Preferably, the colored layer is disposed on the opposite side of the refractive index adjusting layer from the polarizing plate. When the polarizing plate has a λ/4 plate and functions as a circular polarizing plate (details are described below), the colored layer can be suitably used. EXAMPLES Hereinafter, the present invention will be specifically described by examples, but the present invention is not limited by the examples. Furthermore, the measurement method of each characteristic is as follows. [Evaluation] (1) The refractive index of the refractive index adjusting layer was formed into a refractive index adjusting layer on an acrylic film, and then cut into a size of 50 mm × 50 mm, and bonded to a glass plate via an adhesive layer (thickness: 3 mm) surface. The center portion of the back surface of the glass plate (about 20 mm in diameter) was coated with a black marking ink to prepare a sample which was not reflected on the back surface of the glass plate. The sample was attached to an ellipsometer (manufactured by J. A. Woollam Japan Co., Ltd., VASE), and the refractive index was measured at a wavelength of 500 nm and an incident angle of 50 to 80 degrees. (2) Reflectance The total light reflectance (reflectance of light incident on the side from the polarizing plate) of the laminate obtained in the examples and the comparative examples was carried out using a spectrophotometer CM-2600d manufactured by Konica Minolta Co., Ltd. Determination. (3) Front Brightness Each of the laminates obtained in the examples and the comparative examples was placed in uniform illumination of the blue LED in such a manner that the polarizing plate was on the upper side (manufactured by Aitecsystem, Model: TMN150×180-22BD-4) On the polarizing plate side, the brightness was measured by a luminance meter (manufactured by Konica Minolta Co., Ltd., trade name "SR-UL1"). Furthermore, the luminance of uniform illumination is set to 1300 cd/m.² . [Production Example 1] Production of a polarizing plate A polymer film containing polyvinyl alcohol as a main component (manufactured by Kuraray Co., Ltd., trade name "9P75R", thickness: 75 μm, average polymerization degree: 2,400, saponification degree: 99.9 mol % While immersing in a water bath for 1 minute, it was extended 1.2 times in the transport direction, and then immersed in an aqueous solution having an iodine concentration of 0.3% by weight for 1 minute, thereby dyeing the film with a completely unstretched film (original length) as a reference. It extends 3 times in the direction of transport. Then, the stretched film was immersed in an aqueous solution having a boric acid concentration of 4% by weight and a potassium iodide concentration of 5% by weight, and further extended to 6 times in the transport direction based on the original length, and dried at 70 ° C for 2 minutes. A polarizing element is obtained. On the other hand, an alumina-containing colloid-based adhesive was applied to a single side of a triacetyl cellulose (TAC) film (manufactured by Konica Minolta Co., Ltd., product name "KC4UYW", thickness: 40 μm), and both were used. The transport direction is parallelized by winding a pair of convolution layers on one side of the polarizing element obtained in the above. Further, the alumina-containing colloid-based adhesive is based on a polyvinyl alcohol-based resin having an ethyl acetate group (average degree of polymerization: 1200, degree of saponification of 98.5 mol%, degree of acetylation of 5 mol%) 100 parts by weight, 50 parts by weight of methylol melamine is dissolved in pure water to prepare an aqueous solution having a solid content concentration of 3.7% by weight, and is added in an amount of 10% by weight based on 100 parts by weight of the aqueous solution. It was prepared by using 18 parts by weight of an aqueous solution of a positively charged alumina colloid (having an average particle diameter of 15 nm). Then, the same alumina-containing colloid-containing adhesive was applied to the opposite side of the polarizing element, and the saponified 40 μm-thick acrylic resin film was bonded to each other to prepare a polarizing plate. [Production Example 2] Preparation of coating liquid for forming a refractive index adjusting layer (1) Gelation of a ruthenium compound, MTMS (Methyltrimethoxysilane, 0.95 g) as a precursor of a ruthenium compound was dissolved in 2.2 g. Mixture A was prepared in DMSO (Dimethylsulfoxide). To the mixed solution A, 0.5 g of a 0.01 mol/L aqueous oxalic acid solution was added, and the mixture was stirred at room temperature for 30 minutes to thereby hydrolyze MTMS to form a mixed liquid B containing tris(hydroxy)methylnonane. After adding 288% by weight of 28% by weight aqueous ammonia and 0.2 g of pure water to 5.5 g of DMSO, the mixed liquid B was further added thereto, and stirred at room temperature for 15 minutes to carry out tris(hydroxy)methylnonane. Gelation was carried out to obtain a mixed solution C containing a gelatinous quinone compound. (2) Ripening treatment The mixed liquid C containing the gelatinous quinone compound prepared as described above was directly cultured at 40 ° C for 20 hours to carry out a ripening treatment. (3) Crushing treatment Next, the gelatinous cerium compound which has been subjected to the aging treatment as described above is pulverized into granules having a size of several mm to several cm using a spatula. Then, 40 g of IPA (isopropyl alcohol) was added to the mixed solution C, and the mixture was gently stirred, and then allowed to stand at room temperature for 6 hours to decanse the solvent and the catalyst in the gel. The mixture D was subjected to the same decantation treatment three times to obtain a mixed liquid D. Then, the gelatinous quinone compound in the mixed solution D was pulverized (high-pressure medium-free pulverization). The pulverization treatment (high-pressure medium-free pulverization) was carried out using a homogenizer (manufactured by SMT Co., Ltd., trade name "UH-50"), and the gel-like compound in the mixture D' was weighed to 1.85 g and IPA 1.15 g and placed at 5 cc. After being placed in a screw bottle, it was pulverized at 50 W and 20 kHz for 2 minutes. The gelatinous ruthenium compound in the mixed liquid D is pulverized by the pulverization treatment, whereby the mixed liquid D' becomes a sol liquid of the pulverized product. The volume average particle diameter of the pulverized material contained in the mixed liquid D' showing uneven particle size was confirmed by a dynamic light scattering type Nanotrac particle size analyzer (manufactured by Nikkiso Co., Ltd., UPA-EX150 type), and found to be 0.50 to 0.70. Further, the sol solution (mixture C') was 0.75 g, and a solution of a photobase generator (Wako Pure Chemical Industries Co., Ltd.: trade name WPBG266) at a concentration of 1.5% by weight of a MEK (methyl ethyl ketone) solution of 0.062 g, A 5% concentration of bis(trimethoxydecyl)ethane in a MEK solution of 0.036 g was added to obtain a coating liquid for forming a refractive index adjusting layer. [Example 1] The coating liquid for forming a refractive index adjusting layer prepared in Production Example 2 was applied to the surface of the acrylic resin film of the polarizing plate produced in Production Example 1. At this time, the Wet thickness (thickness before drying) of the formed coating layer was about 27 μm. The coating layer was dried at a temperature of 100 ° C for 1 minute, and further, for the coated layer after drying, a light having a wavelength of 360 nm was used at 300 mJ/cm.² The light irradiation amount (energy) is subjected to UV irradiation to obtain a layered body a on which the refractive index adjusting layer is formed on the polarizing plate. The refractive index adjusting layer has a refractive index of 1.15. A commercially available TV (television) (manufactured by Samsung Co., Ltd., trade name "UN65JS9000FXZA") was decomposed to obtain a wavelength conversion material contained in the backlight side, that is, a quantum dot sheet. This quantum dot sheet is used as a light-emitting layer, and is bonded to the low refractive index layer side of the laminated body a via an acrylic adhesive. A laminate A having a polarizing plate, a refractive index adjusting layer, and a light-emitting layer was obtained by the above method. The obtained laminate A was supplied to the above evaluations (2) and (3). The results are shown in Table 1. [Example 2] A laminate B (polarizing plate/refractive index adjusting layer/colored layer) was obtained in the same manner as in Example 1 except that the layered product a and the quantum dot sheet (light-emitting layer) were laminated via a colored layer. / luminescent layer). The obtained layered body B was supplied to the above evaluations (2) and (3). The results are shown in Table 1. Further, the colored layer is formed in the following manner. (Formation of a colored layer) 100 parts by weight of an acrylic polymer obtained by copolymerizing n-butyl acrylate or a hydroxyl group-containing monomer, and a radical generator (manganese peroxide, manufactured by Nippon Oil & Fats Co., Ltd.) "Oyper BMT", 0.3 parts by weight, an isocyanate-based crosslinking agent (manufactured by Tosoh Co., Ltd., trade name "Coronate L"), 1 part by weight, and a pigment (manufactured by Yamamoto Chemical Co., Ltd., trade name "PD-320"), 0.25 parts by weight And a pigment-containing adhesive obtained by 0.2 part by weight of a phenolic antioxidant (manufactured by BASF Japan Co., Ltd., trade name "IRGANOX 1010"). A PET (Polyethylene Terephthalate) substrate (manufactured by Mitsubishi Plastics Co., Ltd., trade name "MRF38CK") was applied to the adhesive to facilitate the peeling of the adhesive, and the thickness of the applicator was 20 μm. After the adhesive was applied and dried at 155 ° C for 2 minutes, the adhesive sample was taken out, and the surface of the adhesive was bonded to the side of the refractive index adjusting layer of the laminate a to form a colored layer. [Comparative Example 1] A laminate C (polarizing plate/light-emitting layer) including a polarizing plate and a light-emitting layer was obtained in the same manner as in Example 1 except that the refractive index adjusting layer was not formed. The obtained layered body C was supplied to the above evaluations (2) and (3). The results are shown in Table 1. [Comparative Example 2] A layered body D was obtained in the same manner as in Example 1 except that the refractive index adjusting layer was not formed and the polarizing plate and the light emitting layer were not laminated. Further, in the laminated body D, an air layer is formed between the polarizing plate and the light-emitting layer. The obtained layered body D was supplied to the above evaluations (2) and (3). The results are shown in Table 1. [Table 1]As is clear from Table 1, according to the present invention, by arranging the refractive index adjusting layer between the polarizing plate and the light-emitting layer, it is possible to achieve both excellent front luminance and external light reflection suppression. On the other hand, in Comparative Example 1, since there was no air layer, external light reflection was small, but the front luminance was lowered. The reason is considered to be that although the light from the backlight causes reflection at the interface between the polarizing plate and the air, the reflected light is absorbed by the polarizing plate. In the present invention, by arranging the refractive index adjusting layer, reflection is generated on the back side of the polarizing plate (specifically, the interface between the refractive index adjusting layer and the light-emitting layer), and the amount of light emitted from the light-emitting layer is increased by reflecting light. The utilization efficiency of light is excellent. Further, in Comparative Example 2, since the air layer was present, the light utilization efficiency was high, but the external light reflection was enhanced.

1‧‧‧Polarized elements

2‧‧‧ phase difference layer

2a‧‧‧ phase difference layer

2b‧‧‧ phase difference layer

3‧‧‧Protective film

10‧‧‧Polar plate

10'‧‧‧Polar polarizer

10''‧‧‧ round polarizer

20‧‧‧ refractive index adjustment layer

30‧‧‧Lighting layer

40‧‧‧Liquid Crystal Unit

41‧‧‧Substrate

41'‧‧‧Substrate

42‧‧‧Liquid layer

50‧‧‧Back side polarizer

100‧‧‧Image display device

110‧‧‧LCD panel

Fig. 1 is a schematic cross-sectional view showing an image display device according to an embodiment of the present invention. Fig. 2 is a schematic cross-sectional view showing a circularly polarizing plate according to an embodiment of the present invention. Fig. 3 is a schematic cross-sectional view showing a circularly polarizing plate according to another embodiment of the present invention.

Claims (8)

An image display device comprising, at least in order, a polarizing plate, a refractive index adjusting layer, and a light emitting layer, wherein the refractive index adjusting layer has a refractive index of 1.2 or less. The image display device of claim 1, wherein the light-emitting layer is a layer that converts a part of wavelength of incident light to emit light. The image display device of claim 1 or 2, wherein the luminescent layer comprises a quantum dot or a phosphor as a wavelength converting material. The image display device according to any one of claims 1 to 3, wherein the luminescent layer is a color filter. The image display device according to any one of claims 1 to 4, wherein the polarizing plate functions as a circular polarizing plate. The image display device according to any one of claims 1 to 5, further comprising a colored layer. The image display device according to any one of claims 1 to 6, wherein the colored layer is disposed between the refractive index adjusting layer and the light emitting layer. An optical laminate comprising a polarizing plate and a refractive index adjusting layer and laminated on an optical member having a light-emitting layer.