JP7002840B2 - Image display device - Google Patents

Description

The present invention relates to an image display device.

In recent years, as an image display device having excellent color reproducibility, an image display device including a light emitting layer made of a light emitting material such as a quantum dot has attracted attention. For example, in a quantum dot film using quantum dots, when light is incident, the quantum dots are excited to emit fluorescence. For example, when a blue LED backlight is used, a part of the blue light is converted into red light and green light by the quantum dot film, and a part of the blue light is emitted as blue light as it is. As a result, white light can be realized. Further, it is said that by using such a quantum dot film, color reproducibility of 100% or more of NTSC ratio can be realized. On the other hand, in recent years, high-level improvements such as low power consumption and reduction of external light reflection have been required for image display devices, and even in image display devices provided with a light emitting layer as described above, the efficiency of light utilization has been improved. Therefore, it is required to reduce the power consumption and further to reduce the reflection of external light.

Japanese Unexamined Patent Publication No. 2015-11518

The present invention has been made to solve the above-mentioned conventional problems, and the main object thereof is an image display device provided with a light emitting layer, which has high light utilization efficiency and low external light reflection. To provide the device.

The image display device of the present invention includes at least a polarizing plate, a refractive index adjusting layer, and a light emitting layer in this order, and the refractive index of the refractive index adjusting layer is 1.2 or less.
In one embodiment, the light emitting layer is a layer that converts a part of the wavelength of the incident light to emit light.
In one embodiment, the light emitting layer comprises quantum dots or phosphors as wavelength conversion materials.
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 comprises a colored layer.
In one embodiment, the colored layer is arranged between the refractive index adjusting layer and the light emitting layer.
According to another aspect of the present invention, there is provided an optical laminate provided with a polarizing plate and a refractive index adjusting layer, which is used by being laminated on an optical member provided with a light emitting layer.

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 provide an image display device having high light utilization efficiency and low external light reflection.

It is a schematic sectional drawing of the image display device by one Embodiment of this invention. It is the schematic sectional drawing of the circular polarizing plate by one Embodiment of this invention. FIG. 3 is a schematic cross-sectional view of a circularly polarizing plate according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

(Definition of terms and symbols)
Definitions of terms and symbols herein are as follows.
(1) Refractive index (nx, ny, nz)
"Nx" is the refractive index in the direction in which the refractive index in the plane is maximized (that is, the slow-phase axis direction), and "ny" is the direction orthogonal to the slow-phase axis in the plane (that is, the phase-advancing axis direction). Is the refractive index of, 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 with light having a wavelength of λ nm at 23 ° C. For example, "Re (550)" is an in-plane phase difference measured with light having a wavelength of 550 nm at 23 ° C. Re (λ) is obtained by the formula: Re = (nx−ny) × d, where d (nm) is the thickness of the layer (film).
(3) Phase difference in the thickness direction (Rth)
“Rth (λ)” is a phase difference in the thickness direction measured with light having a wavelength of λ nm at 23 ° C. For example, "Rth (550)" is a phase difference in the thickness direction measured with light having a wavelength of 550 nm at 23 ° C. Rth (λ) is obtained by the formula: Rth = (nx-nz) × d, where d (nm) is the thickness of the layer (film).
(4) Nz coefficient The Nz coefficient is obtained by Nz = Rth / Re.

A. Overall Configuration of the Image Display Device FIG. 1 is a schematic cross-sectional view of the image display device according to one 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 this order from the visual recognition side. In one embodiment, the light emitting layer is a layer capable of converting a part of the wavelength of the incident light to emit light. In one embodiment, the light emitting layer converts a part of the incident blue to bluish purple light into green light and red light, and emits a part as blue light as it is, thereby producing red light and green light. It emits white light in combination with blue light. FIG. 1 illustrates a case where the image display device is a liquid crystal display device as a typical example. 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, and the polarizing plate 10, the refractive index adjusting layer 20, and the light emitting layer 30 are , Can be a member of the liquid crystal panel 110. Further, the liquid crystal panel 110 may be composed of a liquid crystal cell 40, a viewing side polarizing plate 10 arranged 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. Further, 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 light emitted from the light emitting layer to the refractive index adjusting layer 20 side (for example, the backlight transmitted through the light emitting layer). (Including light from 30) can be reflected on the side surface of the light emitting layer 30 of the refractive index adjusting layer 20. The light reflected here can be wavelength-converted again by the light emitting layer 30. As a result, the light utilization efficiency can be improved. When the refractive index adjusting layer is not arranged, most of the light emitted from the light emitting layer to the polarizing plate side passes through the polarizing plate and is on the surface opposite to the light emitting layer of the polarizing plate (for example, of the polarizing plate). Reflects at the air interface). In that case, the reflected light is absorbed by the polarizing plate, 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, it is possible to improve the efficiency of light utilization without causing absorption of the reflected light by the polarizing plate.

Preferably, the image display device 100 is configured so 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 eliminated as described above, the reflection of external light can be reduced. In the present invention, by appropriately adjusting the refractive index of the refractive index adjusting layer (details will be described later), it is possible to improve the utilization efficiency of the light emitted from the light emitting layer and suppress the reflection of external light. In addition, in this specification, "directly laminated" is a concept including laminating two members via any suitable 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 arranged between the refractive index adjusting layer and the light emitting layer. The colored layer may absorb light of a specific wavelength. The colored layer is preferably used when the polarizing plate has a λ / 4 plate and functions as a circular polarizing plate (details will be described later). A polarizing plate having a λ / 4 plate (circular polarizing plate) exhibits an antireflection function, and a colored layer is arranged, and the colored layer absorbs light of a specific wavelength to prevent reflection of the circular polarizing plate. The function can be improved. Further, by selectively absorbing light in 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. The wavelength of light absorbed by the colored layer can be appropriately adjusted according to the reflection characteristics of the reflector (for example, an image display panel such as a liquid crystal display panel or an organic EL panel) included in the image display device. .. It is preferable that there is no air layer between the refractive index adjusting layer and the colored layer, and between the colored layer and the light emitting layer. In one embodiment, the refractive index adjusting layer and the colored layer are directly laminated. Further, in one embodiment, the colored layer and the light emitting layer are directly laminated.

B. Polarizer As the above-mentioned polarizing plate, any suitable polarizing plate is used. Typically, the polarizing plate is composed of a polarizing element and a protective film arranged on one side or both sides of the polarizing element.

B-1. Polarizer, protective film As the polarizing element, any suitable polarizing element can be used. For example, a dichroic substance such as iodine or a bicolor dye is adsorbed on a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, or an ethylene / vinyl acetate copolymer partially saponified film. Examples thereof include uniaxially stretched films, polyvinyl alcohol dehydrated products, polyvinyl chloride dehydrogenated products, and other polyene-based oriented films. Among these, a decoder in which a dichroic substance such as iodine is adsorbed on a polyvinyl alcohol-based film and uniaxially stretched is particularly preferable because it has a high polarization dichroic ratio. The thickness of the stator is preferably 0.5 μm to 80 μm.

A polarizing element that is uniaxially stretched by adsorbing iodine on a polyvinyl alcohol-based film is typically produced by dyeing by immersing polyvinyl alcohol in an aqueous solution of iodine and stretching it to 3 to 7 times the original length. To. Stretching may be performed after dyeing, stretching while dyeing, or stretching and then dyeing. In addition to stretching and dyeing, it is produced by subjecting it to treatments such as swelling, cross-linking, adjustment, washing with water, and drying. For example, by immersing a polyvinyl alcohol-based film in water and washing it with water before dyeing, it is possible not only to clean the dirt and blocking inhibitor on the surface of the polyvinyl alcohol-based film, but also to swell and dye the polyvinyl alcohol-based film. It is possible to prevent unevenness and the like. The polyvinyl alcohol-based film may be a single-layer film (a film formed by molding a normal film), or may be a polyvinyl alcohol-based resin layer coated and formed on a resin substrate. The 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 coated and formed on a resin substrate is described in, for example, Japanese Patent Application Laid-Open No. 2009-098653.

The splitter preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The simple substance transmittance of the polarizing element is preferably 40% to 45.5%, more preferably 42% to 45%.

The degree of polarization of the polarizing element is 99.9% or more, preferably 99.95% or more.

As the protective film, any suitable film is used. Specific examples of the material that is the main component of such a film include cellulose-based resins such as triacetylcellulose (TAC), (meth) acrylic-based, polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, and polyimide-based. , Polyethersulfone-based, polysulfone-based, polystyrene-based, polynorbornene-based, polyolefin-based, acetate-based transparent resins and the like. Further, thermosetting resins such as acrylic, urethane, acrylic urethane, epoxy and silicone, or ultraviolet curable resins can also be mentioned. In addition to this, for example, glassy polymers such as siloxane-based polymers can also be mentioned. Further, the polymer film described in JP-A-2001-343529 (WO01 / 37007) can also be used. As the material of this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain. Can be used, and examples thereof include a resin composition having an alternating copolymer composed of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer. The polymer film can be, for example, an extruded product of the resin composition. Any suitable adhesive layer or adhesive layer is used for laminating the polarizing element and the protective film. The pressure-sensitive adhesive layer is typically formed of an acrylic pressure-sensitive adhesive. The adhesive 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, by arranging a layer that can function as a λ / 4 plate as a retardation layer, the polarizing plate functions as a circular polarizing plate. By using the circular polarizing plate, the image display device of the present invention has a remarkable effect of preventing external light reflection.

FIG. 2 is a schematic cross-sectional view of a circularly polarizing plate according to one embodiment of the present invention. The circular polarizing plate 10'includes a polarizing element 1 and a retardation layer 2a. The retardation layer 2a can function as a λ / 4 plate. The circular polarizing plate 10'can be arranged so that the polarizing element 1 is on the viewing side. In one embodiment, the circularly 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 may be omitted depending on the application, the configuration of the image display device including the circular polarizing plate, and the like. Further, the circularly polarizing plate may be provided with another protective film (also referred to as an inner protective film: not shown) between the polarizing element and the retardation layer. In the illustrated example, the inner protective film is omitted. In this case, the retardation layer 2 can also function as an inner protective film. With such a configuration, further reduction in thickness of the circularly polarizing plate can be realized.

In the present embodiment, the angle formed by the absorption axis of the polarizing element 1 and the slow axis of the retardation layer 2a is 35 ° to 55 °, preferably 38 ° to 52 °, and more preferably 40 ° to 40 °. It is 50 °, more preferably 42 ° to 48 °, and particularly preferably 44 ° to 46 °. If the angle is in such a range, the desired circular polarization function can be realized. When referring to an angle in the present specification, the angle includes an angle in both clockwise and counterclockwise directions, unless otherwise specified.

FIG. 3 is a schematic cross-sectional view of a circularly polarizing plate according to another embodiment of the present invention. The circular polarizing plate 10 ″ further includes another retardation layer 2b between the polarizing element 1 and the retardation layer 2a (λ / 4 plate). Another retardation layer 2b functions as a λ / 2 plate. In the present specification, for convenience, the retardation layer 2a (λ / 4 plate) is referred to as a first retardation layer, and another retardation layer 2b (λ / 2 plate) is referred to as a second retardation layer. In some cases. The circular polarizing plate 10 ″ of the illustrated example includes a protective film 3 on the side opposite to another retardation layer 2b of the polarizing element 1. Further, the circularly polarizing plate may be provided with another protective film (also referred to as an inner protective film: not shown) between the polarizing element and the retardation layer. In the illustrated example, the inner protective film is omitted. In this case, another 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 °. , More preferably about 75 °. Further, the angle formed by the absorption axis of the polarizing element 1 and the slow axis of the second retardation layer 2b is preferably 10 ° to 20 °, more preferably 13 ° to 17 °, still more preferably. It is about 15 °. By arranging the two retardation layers at the axial angles as described above, a circularly polarizing plate having very excellent circular polarization characteristics (as a result, very excellent antireflection characteristics) can be obtained in a wide band.

B-2-1. First phase difference layer (λ / 4 plate)
The first retardation layer can function as a λ / 4 plate as described above. The in-plane retardation Re (550) of such a 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. be. The first retardation layer typically has a refractive index ellipsoid of nx> ny = nz or nx>ny> nz. In addition, in this specification, for example, "ny = nz" includes not only exactly 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, and more preferably 1 to 1.3.

The thickness of the first retardation layer can be set so that it can function most appropriately as a λ / 4 plate. In other words, the thickness can be set to obtain the desired in-plane phase difference. Specifically, the thickness is preferably 10 μm to 80 μm, more preferably 10 μm to 60 μm, and most preferably 30 μm to 50 μm.

The first retardation layer may exhibit a reverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light, and a positive wavelength dispersion characteristic in which the retardation value decreases according to the wavelength of the measurement light. It may be shown, and may show a flat wavelength dispersion characteristic in which the phase difference value hardly changes with the wavelength of the measured light.

In one embodiment, the first retardation layer exhibits flat wavelength dispersion characteristics. By adopting the first retardation layer exhibiting a flat wavelength dispersion characteristic, excellent antireflection characteristics and oblique reflection hue 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 Re (550). It is 1.02.

In another embodiment, the first retardation layer exhibits reverse dispersion wavelength characteristics. By adopting the first retardation layer exhibiting the inverse dispersion wavelength characteristic, the reflected hue can be improved in the front direction. Further, by adopting the first retardation layer exhibiting the inverse dispersion wavelength characteristic, it is possible to improve other characteristics (for example, luminance) while maintaining a practical reflected hue. In the present embodiment, the Re (450) / Re (550) of the first retardation layer is preferably 0.5 or more and less than 1.0, and more preferably 0.7 to 0.95. The Re (650) / Re (550) of the first retardation layer preferably exceeds 1 and is 1.2 or less, and more preferably 1.01 to 1.15. In the present embodiment, the Nz coefficient of the first retardation layer is preferably 0.3 to 0.7, more preferably 0.4 to 0.6, and even more preferably 0.45 to 0. It is 55, particularly preferably about 0.5. If the Nz coefficient is in such a range, a better reflected hue can be achieved.

The λ / 4 plate is preferably a stretched film of a polymer film. Specifically, a λ / 4 plate can be obtained by appropriately selecting the type of polymer and the stretching treatment (for example, stretching method, stretching temperature, stretching ratio, stretching direction).

Any suitable resin is used as the resin for forming the polymer film. Specific examples thereof include cycloolefin resins such as polynorbornene, polycarbonate resins, cellulose resins, polyvinyl alcohol resins, polysulfone resins and other resins constituting a positive compound refraction film. Of these, norbornene-based resins and polycarbonate-based resins are preferable. Details of the resin forming the polymer film are described in, for example, Japanese Patent Application Laid-Open No. 2014-010291. This description is incorporated herein by reference.

The polynorbornene refers to a (co) polymer obtained by using a norbornene-based monomer having a norbornene ring in a part or all of a starting material (monomer). Examples of the norbornene-based monomer include norbornene and its alkyl and / or anthracene substituents, such as 5-methyl-2-norbornene, 5-dimethyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl. Polar group substituents such as these halogens such as -2-norbornene, 5-ethylidene-2-norbornene; dicyclopentadiene, 2,3-dihydrodicyclopentadiene and the like; dimethanooctahydronaphthalene, alkyl and / or alkylidene thereof. Substituents and polar group substituents such as halogens such as 6-methyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6- Ethyl-1,4: 5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-ethylidene-1,4: 5,8-dimethano-1,4 4a, 5,6,7,8,8a-octahydronaphthalene, 6-chloro-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-Cyano-1,4: 5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-pyridyl-1,4: 5,8-dimethano-1, 4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-methoxycarbonyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octa Hydronaphthalene, etc .; 3-4 dimensions of cyclopentadiene, eg, 4,9: 5,8-dimethano-3a, 4,4a, 5,8,8a, 9,9a-octahydro-1H-benzoinden, 4, Examples thereof include 11: 5,10: 6,9-trimethano-3a, 4,4a, 5,5a, 6,9,9a, 10,10a, 11,11a-dodecahydro-1H-cyclopentadiene and the like.

As the polynorbornene, various products are commercially available. Specific examples include Zeon Corporation's product names "Zeonex" and "Zeonoa", JSR's product name "Arton", TICONA's product name "Topus", and Mitsui Chemicals' product name. "APEL" can be mentioned.

As the polycarbonate-based resin, aromatic polycarbonate is preferably used. Aromatic polycarbonate can be typically obtained by reacting a carbonate precursor with an aromatic divalent phenolic compound. Specific examples of the carbonate precursor include phosgene, bischlorohomates of divalent phenols, diphenyl carbonate, di-p-tolyl carbonate, phenyl-p-tolyl carbonate, di-p-chlorophenyl carbonate, dinaphthyl carbonate and the like. Can be mentioned. Among these, phosgene and diphenyl carbonate are preferable. Specific examples of the aromatic divalent phenol compound include 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, and bis (4-hydroxyphenyl). ) Methan, 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-trimethyl Cyclohexane and the like can be mentioned. 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, and 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane are used. Used. In particular, it is preferable to use 2,2-bis (4-hydroxyphenyl) propane and 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane together.

Examples of the stretching method include horizontal uniaxial stretching, fixed-end biaxial stretching, and sequential biaxial stretching. Specific examples of the fixed-end biaxial stretching include a method of stretching the polymer film in the lateral direction (lateral direction) while running the polymer film in the longitudinal direction. This method may apparently be laterally uniaxially stretched. In addition, diagonal stretching can also be adopted. By adopting diagonal stretching, it is possible to obtain a long stretched film having an orientation axis (slow phase axis) at a predetermined angle with respect to the width direction.

The thickness of the 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 phase difference layer (λ / 2 plate)
The second retardation layer can function as a λ / 2 plate as described above. The in-plane retardation Re (550) of such a 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 typically preferably has a refractive index ellipsoid of nx> ny = nz. The Nz coefficient of the second retardation layer is, for example, 0.9 to 2, preferably 1 to 1.5, and more preferably 1 to 1.3.

The thickness of the second retardation layer can be set so that it can function most appropriately as a λ / 2 plate. In other words, the thickness can be set to obtain the desired in-plane phase difference. 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 adopted as long as the above-mentioned characteristics can be obtained. A liquid crystal material is preferable, and a liquid crystal material (nematic liquid crystal) in which the liquid crystal phase is a nematic phase is more preferable. By using the liquid crystal material, the difference between nx and ny of the obtained second retardation layer can be made much larger than that of the non-liquid crystal material. As a result, the thickness of the second retardation layer for obtaining a desired in-plane retardation can be significantly reduced. As such a liquid crystal material, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The liquid crystal expression mechanism of the liquid crystal material may be either lyotropic or thermotropic. Further, the orientation state of the liquid crystal is preferably homogenius orientation. Further, as the material of the second retardation layer, a resin forming the polymer film may be used.

The second retardation layer may exhibit a reverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light, and a positive wavelength dispersion characteristic in which the retardation value decreases according to the wavelength of the measurement light. It may be shown, and may show a flat wavelength dispersion characteristic in which the phase difference value hardly changes with the wavelength of the measured light. It is preferable to show flat wavelength dispersion characteristics. By adopting a λ / 2 plate having flat wavelength dispersion characteristics, excellent antireflection characteristics and oblique reflection hue can be realized. The retardation layer Re (450) / Re (550) 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 comprises any suitable one or more colorants. Typically, in the colored layer, the colorant is present in the matrix.

In one embodiment, the colored layer selectively absorbs light in a particular wavelength range (ie, has an absorption maximum wavelength in a particular wavelength band). In another embodiment, the colored layer functions to absorb all wavelengths in the visible light region. Preferably, the colored layer selectively absorbs light in a specific wavelength range. If the colored layer is configured to selectively absorb light in a specific wavelength range, it is possible to enhance the antireflection function of the circularly polarizing plate while suppressing a decrease in visible light transmittance (that is, a decrease in brightness). can. 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 the wavelength band in the range of 440 nm to 510 nm. By forming such a colored layer, the reflected hue can be appropriately adjusted.

In another embodiment, the colored layer has an absorption maximum wavelength in the wavelength band in the range of 560 nm to 610 nm. By forming such a colored layer, the reflected hue can be appropriately adjusted.

In yet another embodiment, the colored layer has an absorption maximum wavelength in the wavelength band in the range of 440 nm to 510 nm and 560 nm to 610 nm. With such a configuration, the image display device can be remarkably widened in color gamut. As described above, the colored layer having two or more absorption maximum wavelengths can be obtained by using a plurality of kinds of coloring materials.

The transmittance of the colored layer at the absorption maximum wavelength is preferably 0% to 80%, more preferably 0% to 70%. Within such a range, the above-mentioned effect of the present invention becomes more remarkable.

The visible light transmittance of the colored layer is preferably 30% to 90%, more preferably 30% to 80%. Within such a range, the antireflection function of the circularly polarizing plate can be enhanced while suppressing the decrease in brightness.

The haze value of the colored layer is preferably 15% or less, more preferably 10% or less. By keeping the haze value of the colored layer within such a range, the depolarization of the circularly polarized light transmitted through the retardation layer is prevented, and as a result, the antireflection function of the circularly polarizing plate is effectively exhibited. The smaller the haze value of the colored layer is, the more preferable it is, but the lower limit thereof is, for example, 0.1%.

The thickness of the colored layer is preferably 1 μm to 100 μm, more preferably 2 μm to 30 μm.

(Color material)
Specific examples of the above coloring materials include anthraquinone-based, triphenylmethane-based, naphthoquinone-based, thioindigo-based, perinone-based, perylene-based, squarylium-based, cyanine-based, porphyrin-based, azaporphyrin-based, phthalocyanine-based, subphthalocyanine-based, and quinizarin. System, Polymethin system, Rhodamine system, Oxonol system, Kinone system, Azo system, Xantene system, Azomethin system, Quinacridone system, Dioxazine system, Diketopyrrolopyrrole system, Anthraquinone system, Isodolinone system, Indanslon system, Indigo Examples thereof include dyes such as thioindigo, quinophthalone, quinoline, and triphenylmethane.

In one embodiment, anthraquinone-based, oxime-based, naphthoquinone-based, quinizarin-based, oxonol-based, azo-based, xanthene-based or phthalocyanine-based dyes are used as the coloring material. By using these dyes, it is possible to form a colored layer having an absorption maximum wavelength in a wavelength band in the range of 440 nm to 510 nm.

In one embodiment, as the coloring material, as the coloring layer having an absorption maximum wavelength in the above range, for example, an indigo-based, rhodamine-based, quinacridone-based or porphyrin-based dye is used as the coloring material. By using these dyes, it is possible to form a colored layer having an absorption maximum wavelength in a wavelength band in the range of 560 nm to 610 nm.

Further, a pigment may be used as the coloring material. Specific examples of the pigment include black pigments (carbon black, bone black, graphite, iron black, titanium black, etc.), azo pigments, phthalocyanine pigments, polycyclic pigments (quinacridone, perylene, perinone, etc.). Isoindrinone-based, isoindolin-based, dioxazine-based, thioindigo-based, anthraquinone-based, quinophthalone-based, metal complex-based, diketopyrrolopyrrole-based, dye lake pigments, white / extender pigments (titanium oxide, zinc oxide, sulfide) Zinc, clay, talc, barium sulfate, calcium carbonate, etc.), chromatic pigments (yellow lead, cadmium, chrome vermillion, nickel titanium, chrome titanium, yellow iron oxide, red iron oxide, zinc chromate, lead tan, ultramarine, dark blue, Cobalt blue, chrome green, chromium oxide, bismuth vanadate, etc.), bright material pigments (pearl pigments, aluminum pigments, bronze pigments, etc.), fluorescent pigments (zinc sulfide, strontium sulfide, strontium aluminate, etc.) and the like can be mentioned.

The content ratio of the coloring material may be any appropriate ratio depending on the type of coloring material, desired light absorption characteristics, and the like. The content ratio of the coloring material is, for example, 0.01 part by weight to 100 parts by weight, and more preferably 0.01 part by weight to 50 parts by weight with respect to 100 parts by weight of the matrix material.

When a pigment is used as the coloring material, the number average particle size of the pigment in the matrix is preferably 500 nm or less, more preferably 1 nm to 100 nm. Within such a range, a colored layer having a small haze value can be formed. The number average particle size of the pigment is measured and calculated by observing the cross section of the colored layer.

(matrix)
The matrix may be an adhesive or a resin film. It is preferably an adhesive.

When the matrix is a pressure-sensitive adhesive, any suitable pressure-sensitive adhesive can be used as the pressure-sensitive adhesive. The pressure-sensitive adhesive preferably has transparency and optical isotropic properties. Specific examples of the pressure-sensitive adhesive include rubber-based pressure-sensitive adhesives, acrylic-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, epoxy-based pressure-sensitive adhesives, and cellulose-based pressure-sensitive adhesives. A rubber-based pressure-sensitive adhesive or an acrylic-based pressure-sensitive adhesive is preferable.

The rubber-based polymer of the rubber-based pressure-sensitive adhesive (adhesive composition) is a polymer that exhibits rubber elasticity in a temperature range near room temperature. Preferred rubber-based polymers (A) include styrene-based thermoplastic elastomers (A1), isobutylene-based polymers (A2), and combinations thereof.

Examples of the styrene-based thermoplastic elastomer (A1) include a styrene-ethylene-butylene-styrene block copolymer (SEBS), a styrene-isoprene-styrene block copolymer (SIS), and a styrene-butadiene-styrene block copolymer. (SBS), styrene-ethylene-propylene-styrene block copolymer (SEPS, SIS hydrogenated product), styrene-ethylene-propylene block copolymer (SEP, styrene-isoprene block copolymer hydrogenated product), Examples thereof include styrene-based block polymers such as styrene-isobutylene-styrene block copolymer (SIBS) and styrene-butadiene rubber (SBR). Among these, styrene-ethylene-propylene-styrene block copolymer (SEPS, SIS hydrogenated product), styrene-ethylene- Butylene-styrene block copolymer (SEBS) and styrene-isobutylene-styrene block copolymer (SIBS) are preferable. A commercially available product may be used as the styrene-based thermoplastic elastomer (A1). Specific examples of commercially available products include Kuraray's SEPTON, HYBRAR, Asahi Kasei Chemicals' Tough Tech, and Kaneka's SIBSTAR.

The weight average molecular weight of the styrene-based thermoplastic elastomer (A1) is preferably about 50,000 to 500,000, more preferably about 50,000 to 300,000, and further preferably about 50,000 to 250,000. When the weight average molecular weight of the styrene-based thermoplastic elastomer (A1) is in such a range, it is preferable because both the cohesive force of the polymer and the viscoelasticity can be achieved.

The styrene content in the styrene-based thermoplastic elastomer (A1) is preferably about 5% by weight to 70% by weight, more preferably about 5% by weight to 40% by weight, still more preferably 10% by weight to 20% by weight. It is about% by weight. When the styrene content in the styrene-based thermoplastic elastomer (A1) is in such a range, viscoelasticity due to the soft segment can be ensured while maintaining the cohesive force due to the styrene moiety, which is preferable.

Examples of the isobutylene polymer (A2) include those containing isobutylene as a constituent monomer and having a weight average molecular weight (Mw) of preferably 500,000 or more. The isobutylene-based polymer (A2) may be a homopolymer of isobutylene (polyisobutylene, PIB), and is a copolymer containing isobutylene as a main monomer (that is, a copolymer in which isobutylene is copolymerized in an amount of more than 50 mol%). There may be. Examples of such copolymers include copolymers of isobutylene and normal butylene, copolymers of isobutylene and isoprene (for example, butyl rubbers such as regular butyl rubber, chlorinated butyl rubber, brominated butyl rubber, and partially crosslinked butyl rubber). Examples thereof include these sulfides and modified products (for example, those modified with functional groups such as hydroxyl groups, carboxyl groups, amino groups and epoxy groups). Among these, polyisobutylene (PIB) is preferable because it does not contain a double bond in the main chain and has excellent weather resistance. A commercially available product may be used as the isobutylene polymer (A2). Specific examples of commercially available products include OPPANOL manufactured by BASF.

The weight average molecular weight (Mw) of the isobutylene polymer (A2) is preferably 500,000 or more, more preferably 600,000 or more, and further preferably 700,000 or more. The upper limit of the weight average molecular weight (Mw) is preferably 5 million or less, more preferably 3 million or less, and further preferably 2 million or less. By setting the weight average molecular weight of the isobutylene polymer (A2) to 500,000 or more, a pressure-sensitive adhesive composition having better durability during high-temperature storage can be obtained.

The content of the rubber-based polymer (A) in the pressure-sensitive adhesive (pressure-sensitive adhesive composition) is preferably 30% by weight or more, more preferably 40% by weight or more, and further preferably 40% by weight or more, based on the total solid content of the pressure-sensitive 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, and more preferably 90% by weight or less.

In the rubber-based pressure-sensitive adhesive, the above-mentioned rubber-based polymer (A) may be used in combination with another rubber-based polymer. Specific examples of other rubber-based polymers include butyl rubber (IIR), butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), EPR (binary ethylene-propylene rubber), and EPT (ternary ethylene-propylene rubber). ), Acrylic rubber, urethane rubber, polyurethane-based thermoplastic elastomer; polyester-based thermoplastic elastomer; blend-based thermoplastic elastomer such as a polymer blend of polypropylene and EPT (ternary ethylene-propylene rubber). The blending amount of the other rubber-based polymer is preferably about 10 parts by weight or less with respect to 100 parts by weight of the rubber-based polymer (A).

Acrylic polymers of acrylic pressure-sensitive adhesives (tacket composition) typically contain an alkyl (meth) acrylate as a main component, and as a copolymerization component according to the purpose, an aromatic ring-containing (meth) acrylate, It may contain an amide group-containing monomer, a carboxyl group-containing monomer and / or a hydroxyl group-containing monomer. As used herein, the term "(meth) acrylate" means acrylate and / or methacrylate. Examples of the alkyl (meth) acrylate include linear or branched alkyl groups having 1 to 18 carbon atoms. An aromatic ring-containing (meth) acrylate is a compound having an aromatic ring structure in its structure and containing a (meth) acryloyl group. Examples of the aromatic ring include a benzene ring, a naphthalene ring, and a biphenyl ring. The aromatic ring-containing (meth) acrylate can satisfy durability (particularly, durability against a transparent conductive layer) and can improve display unevenness due to white spots in the peripheral portion. The amide group-containing monomer is a compound containing an amide group in its structure and containing a polymerizable unsaturated double bond such as a (meth) acryloyl group and a vinyl group. The carboxyl group-containing monomer is a compound containing a carboxyl group in its structure and containing a polymerizable unsaturated double bond such as a (meth) acryloyl group and a vinyl group. The hydroxyl group-containing monomer is a compound containing a hydroxyl group in its structure and containing a polymerizable unsaturated double bond such as a (meth) acryloyl group and a vinyl group. Details of the acrylic pressure-sensitive adhesive are described in, for example, Japanese Patent Application Laid-Open No. 2015-199942, and the description of the publication is incorporated herein by reference.

When the matrix 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, a thermosetting resin, or 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 epoxy, (meth) acrylate (eg, methyl methacrylate, butyl acrylate), norbornene, polyethylene, poly (vinyl butyral), poly (vinyl acetate), polyurea, polyurethane, aminosilicone (AMS), and the like. Polyphenylmethylsiloxane, polyphenylalkylsiloxane, polydiphenylsiloxane, polydialkylsiloxane, silsesquioxane, fluorinated silicones, vinyl and hydride substituted silicones, styrene-based polymers (eg, polystyrene, aminopolystyrene (APS), poly (eg, polystyrene, aminopolystyrene (APS), poly) Acrylic nitrile ethylene styrene) (AES)), polymers crosslinked with bifunctional monomers (eg, divinylbenzene), polyester-based polymers (eg, polyethylene terephthalate), cellulose-based polymers (eg, triacetyl cellulose), vinyl chloride-based polymers. , Amid-based polymer, imide-based polymer, vinyl alcohol-based polymer, epoxy-based polymer, silicone-based polymer, acrylic urethane-based polymer. These may be used alone or in combination (eg, blend, copolymer). These resins may be subjected to treatments such as stretching, heating, and pressurization after forming the film. A thermosetting resin or an ultraviolet curable resin is preferable, and a thermosetting resin is more preferable. This is because it can be suitably applied when the optical member of the present invention is manufactured by roll-to-roll.

D. Refractive index adjusting layer The refractive index of the refractive index adjusting layer is 1.2 or less, preferably 1.15 or less, and more preferably 1.01 to 1.1. Within such a range, it is possible to improve the utilization efficiency of the light emitted from the light emitting layer and suppress the reflection of external light.

The refractive index adjusting layer typically has voids inside. The porosity of the refractive index adjusting layer can be any appropriate value. The porosity is, for example, 5% to 99%, preferably 25% to 95%. When the porosity 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 voids inside may have, for example, a structure having at least one particle-like, fibrous-like, or flat plate-like shape. The structure (constituent unit) that forms particles may be real particles or hollow particles, and specific examples thereof include silicone particles, silicone particles having fine pores, silica hollow nanoparticles, and silica hollow nanoparticles. The fibrous structural unit is, for example, nanofibers having a nano-sized diameter, and specific examples thereof include cellulose nanofibers and alumina nanofibers. Examples of the flat plate-shaped structural unit include nanoclay, and specific examples thereof include nano-sized bentonite (for example, Kunipia F [trade name]). Further, in the void structure of the present invention, the single, one or more structural units forming the fine void structure are chemically, for example, directly or indirectly, through catalytic action. Includes connected parts. In the present invention, "indirectly bound" to each other means that the constituent units are bound to each other via a small amount of binder component equal to or less than the amount of the constituent units. The phrase "directly bonded" to each other means that the constituent units are directly bonded to each other without the intervention of a binder component or the like.

Any suitable material may be adopted as the material constituting the refractive index adjusting layer. As the material, for example, the materials described in International Publication No. 2004/113966, Japanese Patent Application Laid-Open No. 2013-254183, and Japanese Patent Application Laid-Open No. 2012-189802 can be adopted. Specifically, for example, silica-based compounds; hydrolyzable silanes and their partial hydrolysates and dehydration condensates; organic polymers; silicon compounds containing silanol groups; silicates in contact with acids and ion exchange resins. Active silica obtained by subjecting to; polymerizable monomers (eg, (meth) acrylic monomers and styrene monomers); curable resins (eg, (meth) acrylic resins, fluorine-containing resins, and urethane resins); These combinations can be mentioned.

Examples of the organic polymer include polyolefins (for example, polyethylene and polypropylene), polyurethanes, and fluorine-containing polymers (for example, a fluorine-containing monomer unit and a fluorine-containing copolymer having a constituent unit for imparting cross-linking reactivity as constituents). Polymers), polyesters (eg, poly (meth) acrylic acid derivatives (here, (meth) acrylic acid means acrylic acid and methacrylic acid, and "(meth)" all have such meanings. )), Polyethers, polyamides, polyimides, polyureas, and polycarbonates.

The material preferably contains a silica-based compound; hydrolyzable silanes, as well as partial hydrolysates and dehydration condensates thereof.

Examples of the silica-based compound include SiO ₂ (silicic anhydride); SiO ₂ and Na ₂ O-B ₂ O ₃ (borosilicate), Al ₂ O ₃ (alumina), B ₂ O ₃ , TiO ₂ , and the like. ZrO ₂ , SnO ₂ , Ce ₂ O ₃ , P ₂ O ₅ , Sb ₂ O ₃ , MoO ₃ , ZnO ₂ , WO ₃ , TiO ₂ -Al ₂ O ₃ , TiO ₂ -ZrO ₂ , In ₂ O ₃ -SnO ₂ and a compound containing at least one compound selected from the group consisting of Sb ₂ O ₃ -SnO ₂ (the above-mentioned "-" indicates a composite oxide);

Examples of the hydrolyzable silanes include hydrolyzable silanes containing an alkyl group which may have a substituent (for example, fluorine). The hydrolyzable silanes and their partially hydrolyzed and dehydrated condensates are preferably alkoxysilanes and silsesquioxane.

The alkoxysilane may be a monomer or an oligomer. The alkoxysilane monomer preferably has three or more alkoxyl groups. Examples of the alkoxysilane monomer include methyltrimethoxysilane, methyltriethoxysilane, phenyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, tetrapropoxysilane, diethoxydimethoxysilane, dimethyldimethoxysilane, and dimethyldi. Ethoxysilane is mentioned. As the alkoxysilane oligomer, a polycondensate obtained by hydrolysis and polycondensation of the above-mentioned monomer is preferable. By using alkoxysilane as the above material, a refractive index adjusting layer having excellent uniformity can be obtained.

Sylsesquioxane is a general term for networked polysiloxanes represented by the general formula RSiO _1.5 (where R represents an organic functional group). Examples of R include an alkyl group (which may be a straight chain or a branched chain and have 1 to 6 carbon atoms), a phenyl group, and an alkoxy group (for example, a methoxy group and an ethoxy group). Examples of the structure of silsesquioxane include a ladder type and a cage type. By using silsesquioxane as the above material, a refractive index adjusting layer having excellent uniformity, weather resistance, transparency, and hardness can be obtained.

Any suitable particles may be adopted as the particles. The particles are typically made of a silica-based compound.

The shape of the silica particles can be confirmed, for example, by observing with a transmission electron microscope. The average particle size of the particles is, for example, 5 nm to 200 nm, preferably 10 nm to 200 nm. By having the above structure, it is possible to obtain a refractive index adjusting layer having a sufficiently low refractive index, and it is possible to maintain the transparency of the refractive index adjusting layer. In the present specification, the average particle size is given by the formula of average particle size = (2720 / specific surface area) from the specific surface area (m ² / g) measured by the nitrogen adsorption method (BET method). It shall mean a value (see Japanese Patent Application Laid-Open No. 1-3171115).

Examples of the method for obtaining the refractive index adjusting layer include JP-A-2010-189212, JP-A-2008-040171, JP-A-2006-01175, Pamphlet International Publication No. 2004/113966, and their references. The method described in is mentioned. Specifically, a silica-based compound; a method for hydrolyzing and polycondensing at least one of hydrolyzable silanes and a partial hydrolyzate and dehydration condensate thereof, porous particles and / or hollow fine particles is used. A method of forming an airgel layer using a springback phenomenon, a pulverized gel obtained by pulverizing a gel obtained by a sol-gel and chemically bonding fine pore particles in the pulverized solution with a catalyst or the like. The method to be used, etc. may be mentioned. However, the refractive index adjusting layer is not limited to this manufacturing method, and may be manufactured by any manufacturing method.

The refractive index adjusting layer is attached to the light emitting layer and the polarizing plate via any suitable adhesive layer (for example, an adhesive layer, an adhesive layer: not shown). When the refractive index adjusting layer is composed of an adhesive, the adhesive layer can be omitted.

The haze of the refractive index adjusting layer is, for example, 0.1% to 30%, preferably 0.2% to 10%.

As for the mechanical strength of the refractive index adjusting layer, for example, it is desirable that the scratch resistance by Bencot (registered trademark) is 60% to 100%.

The anchoring force between the refractive index adjusting layer and the light emitting layer is not particularly limited, but 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. In order to increase the mechanical strength and anchoring force, undercoating treatment, heat treatment, humidification treatment, UV treatment, etc. Corona treatment, plasma treatment, or the like may be performed.

The thickness of the refractive index adjusting layer is preferably 100 nm to 5000 nm, more preferably 200 nm to 4000 nm, further preferably 300 nm to 3000 nm, and particularly preferably 500 nm to 2000 nm. Within such a range, it is possible to realize a refractive index adjusting layer that optically exhibits sufficient functions for light in the visible light region and has excellent durability.

E. Light emitting layer The light emitting layer typically contains a wavelength conversion material. More specifically, the light emitting layer may include a matrix and wavelength conversion materials dispersed in the matrix.

E-1. Matrix As a material constituting the matrix (hereinafter, also referred to as a matrix material), any suitable material can be used. Examples of such materials include resins, organic oxides, and inorganic oxides. The matrix material preferably has low oxygen permeability and moisture permeability, high photostability and chemical stability, a predetermined index of refraction, excellent transparency, and / or. , Has excellent dispersibility for wavelength conversion materials. Practically, the matrix can be composed of a resin film or an adhesive.

E-1-1. When the resin film matrix 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, a thermosetting resin, or 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 epoxy, (meth) acrylate (eg, methyl methacrylate, butyl acrylate), norbornene, polyethylene, poly (vinyl butyral), poly (vinyl acetate), polyurea, polyurethane, aminosilicone (AMS), and the like. Polyphenylmethylsiloxane, polyphenylalkylsiloxane, polydiphenylsiloxane, polydialkylsiloxane, silsesquioxane, fluorinated silicones, vinyl and hydride substituted silicones, styrene-based polymers (eg, polystyrene, aminopolystyrene (APS), poly (eg, polystyrene, aminopolystyrene (APS), poly) Acrylic nitrile ethylene styrene) (AES)), polymers crosslinked with bifunctional monomers (eg, divinylbenzene), polyester-based polymers (eg, polyethylene terephthalate), cellulose-based polymers (eg, triacetyl cellulose), vinyl chloride-based polymers. , Amid-based polymer, imide-based polymer, vinyl alcohol-based polymer, epoxy-based polymer, silicone-based polymer, acrylic urethane-based polymer. These may be used alone or in combination (eg, blend, copolymer). These resins may be subjected to treatments such as stretching, heating, and pressurization after forming the film. A thermosetting resin or an ultraviolet curable resin is preferable, and a thermosetting resin is more preferable.

E-1-2. When the pressure-sensitive adhesive matrix is a pressure-sensitive adhesive, any suitable pressure-sensitive adhesive can be used as the pressure-sensitive adhesive. The pressure-sensitive adhesive preferably has transparency and optical isotropic properties. Specific examples of the pressure-sensitive adhesive include rubber-based pressure-sensitive adhesives, acrylic-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, epoxy-based pressure-sensitive adhesives, and cellulose-based pressure-sensitive adhesives. A rubber-based pressure-sensitive adhesive or an acrylic-based pressure-sensitive adhesive is preferable.

E-2. Wavelength conversion material The wavelength conversion material can control the wavelength conversion characteristics of the light emitting layer. The wavelength conversion material may be, for example, a quantum dot or a phosphor.

The content of the wavelength conversion material in the light emitting layer (the total content when two or more kinds are used) is preferably 0 with respect to 100 parts by weight of the matrix material (typically, the solid content of the resin or the pressure-sensitive adhesive). It is 0.01 part by weight to 50 parts by weight, more preferably 0.01 part by weight to 30 parts by weight. When the content of the wavelength conversion material is within such a range, it is possible to realize an image display device having excellent hue balance in all RGB.

E-2-1. Quantum dots The emission center wavelength of quantum dots can be adjusted by the material and / or composition, particle size, shape, etc. of the quantum dots.

Quantum dots can be made of any suitable material. The quantum dots may be preferably composed of an inorganic material, more preferably an inorganic conductor material or an inorganic semiconductor material. Examples of the semiconductor material include II-VI group, III-V group, IV-VI group, and IV group semiconductors. Specific examples include Si, Ge, Sn, Se, Te, B, C (including diamonds), P, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdSeZn, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, GeSe, Se PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si ₃ N ₄ , Ge ₃ N ₄ , Al ₂ O ₃ , (Al, Ga, In) ₂ (S, Se, Te) ₃ , Al ₂ CO can be mentioned. These may be used alone or in combination of two or more. Quantum dots may include p-type dopants or n-type dopants. Further, the quantum dots may have a core-shell structure. In the core-shell structure, any suitable functional layer (single layer or multiple layers) may be formed around the shell depending on the purpose, and the shell surface may be surface-treated and / or chemically modified. good.

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 flaky shape, a plate shape, an elliptical spherical shape, and an amorphous shape.

As the size of the quantum dots, any appropriate size may be adopted depending on the desired emission wavelength. The size of the quantum dots is preferably 1 nm to 10 nm, more preferably 2 nm to 8 nm. When the size of the quantum dots is within such a range, each of green and red emits sharp light, and high color rendering properties can be realized. For example, green light can emit light when the size of the quantum dot is about 7 nm, and red light can emit light when the size of the quantum dot is about 3 nm. The size of the quantum dots is, for example, an average particle size when the quantum dots are spherical, and is a dimension along the minimum axis in the shape when the quantum dots have other shapes.

Details of the quantum dots are described in, for example, JP-A-2012-169271, JP-A-2015-102857, JP-A-2015-65158, JP-A-2013-544018, and JP-A-2010-533976. The description of these publications is incorporated herein by reference. Commercially available products may be used for the quantum dots.

E-2-2. Fluorescent material As the fluorescent material, any suitable fluorescent material capable of emitting light of a desired color depending on the purpose can be used. Specific examples include a red fluorescent substance and a green fluorescent substance.

Examples of the red phosphor include a complex fluoride phosphor activated with Mn ⁴⁺ . The complex fluoride phosphor contains at least one coordination center (for example, M described later), is surrounded by a fluoride ion acting as a ligand, and counterion (for example, A described later) as necessary. ) Refers to a coordination compound whose charge is compensated. Specific examples thereof include A ₂ [MF ₅ ]: Mn ⁴⁺ , A ₃ [MF ₆ ]: Mn ⁴⁺ , Zn ₂ [MF ₇ ]: Mn ⁴⁺ , A [In ₂ F ₇ ]: Mn ⁴⁺ , A ₂ [. M'F ₆ ]: Mn ⁴⁺ , E [M'F ₆ ]: Mn ⁴⁺ , A ₃ [ZrF ₇ ]: Mn ⁴⁺ , Ba _0.65 Zr _0.35 F _2.70 : Mn ⁴⁺ . Here, A is Li, Na, K, Rb, Cs, NH ₄ 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 composite fluoride phosphor having a coordination number of 6 at the coordination center is preferable. Details of such a red phosphor are described in, for example, Japanese Patent Application Laid-Open No. 2015-8427. The description of the publication is incorporated herein by reference in its entirety.

Examples of the green phosphor include a compound containing a solid solution of sialon having a β-type Si _{3N 4 crystal} structure as a main component. Preferably, the treatment is performed so that the amount of oxygen contained in such a sialon crystal is a specific amount (for example, 0.8% by mass) or less. By performing such a process, a green phosphor having a narrow peak width and emitting sharp light can be obtained. Details of such a green phosphor are described in, for example, Japanese Patent Application Laid-Open No. 2013-28814. The description of the publication is incorporated herein by reference in its entirety.

The light emitting layer may be a single layer or may have a laminated structure. When the light emitting layers have a laminated structure, each layer may typically contain wavelength conversion materials having different light emitting properties.

The thickness of the light emitting layer (in the case of having a laminated structure, the total thickness thereof) is preferably 1 μm to 500 μm, and more preferably 100 μm to 400 μm. When the thickness of the light emitting layer is within such a range, conversion efficiency and durability can be excellent. When the light emitting layer has a laminated structure, the thickness of each layer is preferably 1 μm to 300 μm, more preferably 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, it is possible to obtain an image display device having less external light reflection even if a light emitting layer having a high reflectance is used. The upper limit of the visible light reflectance is, for example, 90%.

F. Other members F-1. Backlight Examples of the light source included in the backlight include a cold cathode fluorescent lamp (CCFL), an LED light source, and the like. In one embodiment, the backlight comprises an LED light source. If 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) is used.

The backlight may be a direct type type or an edge light type.

In addition to the light source, the backlight may further include other members such as a light guide plate, a diffuser plate, and a prism sheet, if necessary.

F-2. Liquid crystal panel The liquid crystal panel 110 is typically a liquid crystal cell 40, a polarizing plate (viewing side polarizing plate) 10 arranged on the viewing side of the liquid crystal cell 40, and the liquid crystal cell. It is provided with a back side polarizing plate 50 arranged on the back side of the above. In one embodiment, the polarizing plate (viewing side polarizing plate) 10 and the back surface side polarizing plate 50 may be arranged so that their respective absorption axes are substantially orthogonal or parallel to each other.

The liquid crystal cell 40 has a pair of substrates 41, 41'and a liquid crystal layer 42 as a display medium sandwiched between the substrates. In a general configuration, one substrate 41 is provided with a color filter (light emitting layer 30) and a black matrix, and the other substrate 41'is provided with a switching element for controlling the electro-optical characteristics of the liquid crystal and this switching. A scanning line that gives a gate signal to the element, a signal line that gives a source signal, and a pixel electrode and a counter electrode are provided. The spacing (cell gap) between the substrates can be controlled by a spacer or the like. For example, an alignment film made of polyimide can be provided on the side of the substrate in contact with the liquid crystal layer.

In one embodiment, the liquid crystal layer comprises liquid crystal molecules oriented in a homeotropic arrangement in the absence of an electric field. Such a liquid crystal layer (as a result, a liquid crystal cell) typically exhibits a three-dimensional refractive index of nz> nx = ny. As a drive mode using liquid crystal molecules oriented in a homeotropic arrangement in the absence of an electric field, for example, a vertical alignment (VA) mode can be mentioned. The VA mode includes a multi-domain VA (MVA) mode.

In another embodiment, the liquid crystal layer comprises liquid crystal molecules oriented in a homogeneous arrangement in the absence of an electric field. Such a liquid crystal layer (as a result, a liquid crystal cell) typically exhibits a three-dimensional refractive index of nx> ny = nz. In addition, in this specification, 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. Typical examples of the drive mode using the liquid crystal layer exhibiting such a three-dimensional refractive index include an in-plane switching (IPS) mode, a fringe field switching (FFS) mode, and the like. The above IPS mode includes a super inplane switching (S-IPS) mode and an advanced super inplane switching (AS-IPS) mode in which a V-shaped electrode, a zigzag electrode, or the like is adopted. Further, the FFS mode described above includes an advanced fringe field switching (A-FFS) mode and an ultra fringe field switching (U-FFS) mode in which a V-shaped electrode, a zigzag electrode, or the like is adopted.

Any suitable polarizing plate can be used as the back-side polarizing plate.

G. Optical Laminates According to another aspect of the invention, optical laminates are provided. The optical laminate includes a polarizing plate and a refractive index adjusting layer. As the polarizing plate, the polarizing plate described in Section B above can be used. As described in Section B, the polarizing plate may be a polarizing plate that can function as a circular polarizing plate. As the refractive index adjusting layer, the refractive index adjusting layer described in Section D above is used. The optical laminate of the present invention is used by laminating and laminating it on an optical member provided with a light emitting layer. The light emitting layer is a layer capable of converting a part of the wavelength of the incident light to emit light, and 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 suitable adhesive or adhesive.

In one embodiment, the optical laminate may further comprise a colored layer. Preferably, the colored layer is arranged on the opposite side of the polarizing plate of the refractive index adjusting layer. The colored layer is preferably used when the polarizing plate has a λ / 4 plate and functions as a circular polarizing plate (details will be described later).

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. The measurement method for each characteristic is as follows.

[evaluation]
(1) Refractive index of the refractive index adjusting layer After forming the refractive index adjusting layer on the acrylic film, it is cut into a size of 50 mm × 50 mm and bonded to the surface of a glass plate (thickness: 3 mm) via an adhesive layer. did. The central portion (about 20 mm in diameter) of the back surface of the glass plate was painted with black magic to prepare a sample that does not reflect on the back surface of the glass plate. The above sample was set in an ellipsometer (manufactured by JA Woollam Japan: VASE), and the refractive index was measured under the conditions of a wavelength of 500 nm and an incident angle of 50 to 80 degrees.
(2) Reflectance
The total light reflectance (reflectance when light is incident from the polarizing plate side) of the laminates obtained in Examples and Comparative Examples is measured using a spectrophotometer CM-2600d manufactured by Konica Minolta. did.
(3) Front Luminance Uniform light emission illumination of blue LED (manufactured by Aitec System Co., Ltd .: model number: TMN150 × 180-22BD-) with the polarizing plate on the upper side of each of the laminates obtained in Examples and Comparative Examples. It was placed on 4), and the luminance was measured from the polarizing plate side with a luminance meter (manufactured by Konica Minolta, trade name "SR-UL1"). The emission brightness of the uniform emission illumination was set to 1300 cd / m ² .

[Production Example 1] Preparation of polarizing plate A polymer film containing polyvinyl alcohol as a main component (manufactured by Kuraray, trade name "9P75R", thickness: 75 μm, average degree of polymerization: 2,400, degree of saponification: 99.9 mol% ) Is immersed in a water bath for 1 minute and stretched 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 to be completely stretched in the transport direction while being dyed. It was stretched three times based on the uncoated film (original length). Next, while immersing this stretched film in an aqueous solution having a boric acid concentration of 4% by weight and a potassium iodide concentration of 5% by weight, the stretched film was further stretched up to 6 times in the transport direction based on the original length, and dried at 70 ° C. for 2 minutes. By doing so, a substituent was obtained.
On the other hand, an alumina colloid-containing adhesive was applied to one side of a triacetyl cellulose (TAC) film (manufactured by Konica Minolta, product name "KC4UYW", thickness: 40 μm), and this was applied to one side of the above-mentioned polarizing element. They were laminated by roll-to-roll so that the transport directions of both were parallel. The alumina colloid-containing adhesive is methylol melamine based on 100 parts by weight of a polyvinyl alcohol-based resin having an acetoacetyl group (average polymerization degree 1200, saponification degree 98.5 mol%, acetoacetylation degree 5 mol%). 50 parts by weight is dissolved in pure water to prepare an aqueous solution having a solid content concentration of 3.7% by weight, and an alumina colloid having a positive charge (average particle diameter of 15 nm) is added to 100 parts by weight of this aqueous solution to have a solid content concentration of 10. It was prepared by adding 18 parts by weight of an aqueous solution contained in% by weight. Subsequently, a similar alumina colloid-containing adhesive was applied to the opposite side of the polarizing element, and a saponified 40 μm-thick acrylic resin film was attached to prepare a polarizing plate.

[Production Example 2] Preparation of a coating solution for forming a refractive index adjusting layer (1) Gelation of a silicon compound 0.95 g of MTMS, which is a precursor of a silicon compound, is dissolved in 2.2 g of DMSO to prepare a mixed solution A. Prepared. MTMS is hydrolyzed by adding 0.5 g of a 0.01 mol / L oxalic acid aqueous solution to this mixed solution A and stirring at room temperature for 30 minutes to produce a mixed solution B containing tris (hydroxy) methylsilane. did.
To 5.5 g of DMSO, 0.38 g of 28% by weight aqueous ammonia and 0.2 g of pure water were added, and then the above mixture B was added and stirred at room temperature for 15 minutes to obtain Tris ( Hydroxy) methylsilane was gelled to obtain a mixed solution C containing a gelled silicon compound.
(2) Aging treatment The mixed solution C containing the gelled silicon compound prepared as described above was incubated as it was at 40 ° C. for 20 hours for aging treatment.
(3) Crushing Treatment Next, the gelled silicon compound aged as described above was crushed into granules having a size of several mm to several cm using a spatula. Then, 40 g of IPA was added to the mixture C, and the mixture was lightly stirred and then allowed to stand at room temperature for 6 hours to decant the solvent and catalyst in the gel. The same decantation treatment was carried out three times to replace the solvent, and a mixed solution D was obtained. Next, the gelled silicon compound in the mixed solution D was pulverized (high pressure medialess pulverization). For the pulverization treatment (high-pressure medialess pulverization), a homogenizer (manufactured by SMTE, trade name "UH-50") was used, and 1.85 g of the gel compound and IPA in the mixed solution D'were placed in a 5 cc screw bottle. After weighing .15 g, pulverization was performed for 2 minutes under the conditions of 50 W and 20 kHz.
By this pulverization treatment, the gelled silicon compound in the mixed solution D was pulverized, so that the mixed solution D'became a sol solution of the pulverized product. The volume average particle size showing the variation in the particle size of the pulverized material contained in the mixed solution D'was confirmed by a dynamic light scattering type nanotrack particle size analyzer (UPA-EX150 type manufactured by Nikkiso Co., Ltd.) and found to be 0.50 to. It was 0.70. Further, with respect to 0.75 g of this sol solution (mixed solution C'), 0.062 g of a 1.5 wt% MEK (methyl ethyl ketone) solution of a photobase generator (Wako Pure Chemical Industries, Ltd .: trade name WPBG266) was added. A 5% concentration MEK solution of bis (trimethoxysilyl) ethane was added at a ratio of 0.036 g to obtain a coating liquid for forming a refractive index adjusting layer.

[Example 1]
The coating liquid for forming the 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 coated layer was treated at a temperature of 100 ° C. for 1 minute and dried, and the dried coated layer was further irradiated with UV at a light irradiation amount (energy) of 300 mJ / cm ² using light having a wavelength of 360 nm. A laminated body a having a refractive index adjusting layer formed on the polarizing plate was obtained. The refractive index of this refractive index adjusting layer was 1.15.
A commercially available TV (manufactured by Samsung, trade name "UN65JS9000FXZA") was disassembled to obtain a wavelength conversion material contained in the backlight side, that is, a quantum dot sheet. The quantum dot sheet was used as a light emitting layer, and was bonded to the low refractive index layer side of the laminated body a via an acrylic pressure-sensitive adhesive.
As described above, a laminated body A including a polarizing plate, a refractive index adjusting layer, and a light emitting layer was obtained. The obtained laminate A was subjected to the above evaluations (2) and (3). The results are shown in Table 1.

[Example 2]
Laminated body B (polarizing plate / refractive index adjusting layer / colored layer / light emitting layer) in the same manner as in Example 1 except that the laminated body a and the quantum dot sheet (light emitting layer) are laminated via the colored layer. Got The obtained laminate B was subjected to the above evaluations (2) and (3). The results are shown in Table 1. The colored layer was formed as follows.
(Formation of colored layer)
0.3 parts by weight of a radical generator (benzoyl peroxide, manufactured by Nippon Oil & Fats Co., Ltd., trade name "Niper BMT") is added to 100 parts by weight of an acrylic polymer obtained by copolymerizing n-butyl acrylate and a hydroxyl group-containing monomer. , Isocyanate-based cross-linking agent (manufactured by Toso Co., Ltd., trade name "Coronate L") by 1 part by weight, dye (manufactured by Yamamoto Kasei Co., Ltd., trade name "PD-320") by 0.25 parts by weight, phenol-based antioxidant (manufactured by Yamamoto Kasei Co., Ltd., trade name "PD-320") A dye-containing pressure-sensitive adhesive containing 0.2 parts by weight of BASF Japan, trade name "IRGANOX1010") was produced. The above adhesive is applied to an applicator to a thickness of 20 μm on a PET substrate (manufactured by Mitsubishi Plastics, trade name “MRF38CK”) that has been treated to facilitate peeling of the adhesive, and dried at 155 ° C for 2 minutes. After that, the pressure-sensitive adhesive sample was taken out, and the pressure-sensitive adhesive surface was bonded to the refractive index adjusting layer side of the laminated body a to form a colored layer.

[Comparative Example 1]
A laminate C (polarizing plate / light emitting layer) containing 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 laminate C was subjected to the above evaluations (2) and (3). The results are shown in Table 1.

[Comparative Example 2]
A laminated body D was obtained in the same manner as in Example 1 except that the polarizing plate and the light emitting layer were laminated without forming the refractive index adjusting layer and without laminating the polarizing plate and the light emitting layer. In the laminated body D, an air layer was formed between the polarizing plate and the light emitting layer. The obtained laminate D was subjected to the above evaluations (2) and (3). The results are shown in 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 suppression of external light reflection. can. On the other hand, in Comparative Example 1, since there is no air layer, the external light reflection is small, but the front luminance is low. It is considered that this is because the light from the backlight is reflected at the interface between the polarizing plate and the air, but the reflected light is absorbed by the polarizing plate. In the present invention, by arranging the refractive index adjusting layer, reflection occurs on the back surface side of the polarizing plate (specifically, the interface between the refractive index adjusting layer and the light emitting layer), and the reflected light emits light from the light emitting layer. The amount will increase, and the efficiency of light utilization will be excellent. Further, in Comparative Example 2, due to the presence of the air layer, the light utilization efficiency is high, but the external light reflection becomes strong.

10 Polarizing plate 20 Refractive index adjustment layer 30 Light emitting layer 100 Image display device

Claims (5)

At least, a polarizing plate, a refractive index adjusting layer, a colored layer, and a light emitting layer are provided in this order.
The polarizing plate and the refractive index adjusting layer are directly laminated, the refractive index adjusting layer and the colored layer are directly laminated, and the colored layer and the light emitting layer are directly laminated.
The refractive index of the refractive index adjusting layer is 1.2 or less, and the refractive index is 1.2 or less.
The colored layer is a layer that absorbs light having a predetermined wavelength.
The light emitting layer is a layer that converts a part of the wavelength of the incident light to emit light.
Image display device. The image display device according to claim 1, wherein the light emitting layer contains a quantum dot or a phosphor as a wavelength conversion material. The image display device according to claim 1 or 2, wherein the light emitting layer is a color filter. The image display device according to any one of claims 1 to 3, wherein the polarizing plate functions as a circular polarizing plate. The image display device according to any one of claims 1 to 4, wherein the refractive index adjusting layer has a porosity of 5% to 99%.

Images