KR102223409B1 - Backlight unit and liquid crystal display device - Google Patents

Abstract

An object of the present invention is to provide a wavelength conversion member capable of exhibiting excellent luminous efficiency.
In order to solve such a problem, as a wavelength conversion member having a wavelength conversion layer including quantum dots that are excited by excitation light to emit fluorescence, the wavelength conversion layer includes the quantum dots and oxygen transmission coefficient A reducing agent is included, and the oxygen transmission coefficient converted per 1 mm of the thickness of the wavelength conversion layer is less than 150.0 cm 3 /m 2 /day/atm, and the oxygen transmission coefficient reducing agent is in the wavelength conversion layer , 30% or more of an oxygen transmission coefficient converted into 10 parts by mass of the oxygen transmission coefficient reducing agent content per 100 parts by mass of the wavelength conversion layer excluding the oxygen transmission coefficient reducing agent, per 1 mm of the thickness of the wavelength conversion layer. A wavelength converting member, a backlight unit, and a liquid crystal display device, which are compounds that exhibit reduced oxygen transmission coefficient reduction ability, are provided.

Description

Backlight unit and liquid crystal display device {BACKLIGHT UNIT AND LIQUID CRYSTAL DISPLAY DEVICE}

The present invention relates to a wavelength conversion member, a backlight unit including the wavelength conversion member, and a liquid crystal display device.

BACKGROUND ART Flat panel displays such as a liquid crystal display device (hereinafter, also referred to as an LCD (Liquid Crystal Display)) have low power consumption and are widely used year by year as a space-saving image display device. The liquid crystal display device is composed of at least a backlight and a liquid crystal cell, and usually further includes members such as a backlight-side polarizing plate and a viewing-side polarizing plate.

In the flat panel display market, improvement in color reproducibility is progressing as an improvement in LCD performance. In this regard, in recent years, as a light emitting material, quantum dots (also referred to as quantum dots, QDs, and quantum dots) are attracting attention (see Patent Document 1). For example, when excitation light enters a wavelength conversion member including quantum dots from a backlight, the quantum dots are excited to emit fluorescence. Here, by using quantum dots having different light emission characteristics, red light, green light, and blue light may be emitted to realize white light. Fluorescence by quantum dots has a small half-value width, so the obtained white light has high luminance and excellent color reproducibility. With the progress of the three-wavelength light source technology using quantum dots, the color reproduction range is expanded from 72% to 100% of the current TV standard (FHD (Full High Definition), NTSC (National Television System Committee)). have.

Japanese Special Publication No. 2013-544018

In the quantum dot, there is a problem that when contacted with oxygen, it deteriorates and the luminous efficiency decreases. It is thought that this is to cause the photooxidation reaction of the quantum dot by contact with oxygen. Therefore, in order to obtain a wavelength conversion member capable of exhibiting excellent luminous efficiency, it is necessary to suppress deterioration of the quantum dot due to oxygen.

In view of the above points, an object of the present invention is to provide a wavelength conversion member capable of exhibiting excellent luminous efficiency.

The inventors of the present invention repeated intensive studies in order to achieve the above object, as a result of the following wavelength conversion member:

A wavelength conversion member having a wavelength conversion layer including quantum dots that are excited by excitation light to emit fluorescence,

The wavelength conversion layer contains a quantum dot and an oxygen transmission coefficient reducing agent,

The oxygen transmission coefficient converted per 1 mm of the thickness of the wavelength conversion layer is less than 150.0 cm 3 /m 2 /day/atm, and

The oxygen transmission coefficient reducing agent is converted into per 10 parts by mass of the oxygen transmission coefficient reducing agent content per 100 parts by mass of the wavelength conversion layer excluding the oxygen transmission coefficient reducing agent in the wavelength conversion layer, per 1 mm of the thickness of the wavelength conversion layer. A wavelength conversion member, which is a compound exhibiting an oxygen transmission coefficient reduction ability that reduces an oxygen transmission coefficient by 30% or more,

By this, it was newly discovered that the above object can be achieved. Hereinafter, this point will be further described. In addition, in the present invention and this specification, the content of the oxygen transmission coefficient reducing agent in the wavelength conversion layer is expressed as a value obtained by excluding the oxygen transmission coefficient reducing agent and making the mass of the wavelength conversion layer 100 parts by mass. This value can be regarded as the same as the total amount of 100 parts by mass excluding the solvent and the oxygen transmission coefficient reducing agent of the quantum dot-containing polymerizable composition used to form the wavelength conversion layer. Therefore, a value calculated from the formulation of the quantum dot-containing polymerizable composition may be employed as the content of the oxygen transmission coefficient reducing agent in the wavelength conversion layer.

Regarding preventing deterioration of quantum dots due to oxygen, in Patent Document 1, in order to protect the quantum dots from oxygen, etc., a barrier film is provided on the main surface of the wavelength conversion layer containing the quantum dots (the main surface will be described later). Lamination is disclosed. In addition, Patent Document 1 discloses coating the entire outer surface including the side surface of the wavelength conversion layer in addition to the barrier film or as a replacement for the barrier film.

Laminating the barrier film as described above is one of effective means for preventing a decrease in the luminous efficiency of the quantum dots since it is possible to suppress the intrusion of oxygen from the main surface of the wavelength conversion layer. However, in a barrier film, it is not possible to prevent intrusion of oxygen from a surface (for example, a side surface) that is not protected by this layer. On the other hand, as disclosed in Patent Document 1, by coating the entire outer surface of the wavelength conversion layer, it becomes possible to suppress the intrusion of oxygen from the surface not protected by the barrier film. However, for this purpose, after the wavelength conversion member including the wavelength conversion layer is cut to a product size (for example, punched by a punching machine), a coating is applied, and productivity is lowered.

Therefore, the present inventors argue that in order to prevent a decrease in luminous efficiency due to deterioration of quantum dots while maintaining productivity, it is desirable to reduce the amount of oxygen intrusion into the layer by making the wavelength conversion layer itself difficult to transmit oxygen. I came to think. In addition, the inventors of the present invention continued to study more intensively, and as a result of including the compound having the above-described oxygen transmission coefficient reduction ability (oxygen transmission coefficient reducing agent) in the wavelength conversion layer, the oxygen transmission coefficient converted into a thickness per 1 mm , To obtain a wavelength conversion member having a wavelength conversion layer of less than 150.0 cm 3 /m 2 /day/atm, the wavelength conversion member according to an aspect of the present invention was completed.

In one embodiment, the wavelength conversion layer contains 1 to 50 parts by mass of an oxygen transmission coefficient reducing agent.

In one embodiment, the oxygen permeation coefficient reducing agent is a biphenyl compound, a hydrogenated biphenyl compound, a terphenyl compound, a bisphenol compound, a hydrogenated bisphenol compound, a trityl compound, a hydrogenated trityl compound, a rosin compound, a novolac compound, a cardo compound. , A benzophenone compound, and a dialkyl ketone compound.

In one aspect, the oxygen permeation coefficient reducing agent is a compound having a molecular weight of 2000 or less.

In one embodiment, the wavelength conversion layer is at least one selected from the group consisting of a quantum dot and an oxygen transmission coefficient reducing agent, and a monofunctional (meth)acrylate compound, a polyfunctional (meth)acrylate compound, and an epoxy compound. It is a cured layer formed by curing a polymerizable composition containing a polymerizable compound.

In one aspect, the thickness of the wavelength conversion layer is in the range of 1 to 500 µm.

In one aspect, the quantum dot,

Quantum dot A having an emission center wavelength in a wavelength band in the range of 600 nm to 680 nm,

Quantum dot B having an emission center wavelength in a wavelength band ranging from 500 nm to 600 nm, and

It is at least one type selected from the group consisting of quantum dots C having a light emission center wavelength in a wavelength band in the range of 400 nm to 500 nm.

In one aspect, the wavelength conversion member has at least one layer selected from the group consisting of an inorganic layer and an organic layer on at least one main surface of the wavelength conversion layer. Here, the "main surface" refers to the surface (surface, back surface) of the wavelength conversion layer disposed on the visible side or the backlight side when the wavelength conversion member is used.

In one aspect, the wavelength conversion member has at least one layer selected from the group consisting of an inorganic layer and an organic layer, respectively, on one major surface and the other major surface of the wavelength conversion layer.

A further aspect of the present invention relates to a backlight unit including at least the wavelength conversion member and a light source.

In one aspect, the light source has a light emission center wavelength in a wavelength band of 430 nm to 480 nm.

A further aspect of the present invention relates to a liquid crystal display device including at least the backlight unit and a liquid crystal cell.

According to one aspect of the present invention, it becomes possible to provide a wavelength conversion member capable of exhibiting excellent luminous efficiency, a backlight unit including the wavelength conversion member, and a liquid crystal display device.

1(a) and (b) are explanatory diagrams of an example of a backlight unit including a wavelength conversion member according to an aspect of the present invention.
2 is an example of a liquid crystal display device according to an aspect of the present invention.
3 is a schematic configuration diagram of an example of an apparatus for manufacturing a wavelength conversion member.
4 is a partially enlarged view of the manufacturing apparatus shown in FIG. 3.

Although the following description is made based on a typical embodiment of the present invention, the present invention is not limited to such an embodiment. In addition, in the present invention and this specification, the numerical range indicated by using "-" means a range including the numerical values described before and after "-" as a lower limit value and an upper limit value.

In the present invention and this specification, the "half width" of the peak means the width of the peak at 1/2 of the peak height. In addition, light having an emission center wavelength in a wavelength band of 400 to 500 nm, preferably 430 to 480 nm, is referred to as blue light, and light having an emission center wavelength in a wavelength band of 500 to 600 nm is referred to as green light. , Light having a light emission center wavelength in a wavelength band of 600 to 680 nm is referred to as red light.

In the present invention and the present specification, the "polymerizable composition" is a composition containing at least one polymerizable compound, and has a property of curing when polymerization treatment such as light irradiation or heating is performed. In addition, the "polymerizable compound" is a compound containing one or more polymerizable groups in one molecule. The polymerizable group is a group that may be involved in a polymerization reaction. The above details will be described later.

In addition, in the present invention and the present specification, descriptions regarding angles such as orthogonality shall include the range of errors allowed in the technical field to which the present invention belongs. For example, it means within a range of less than strict angle ±10°, and the error with the strict angle is preferably 5° or less, and more preferably 3° or less.

[Wavelength conversion member]

A wavelength conversion member according to an aspect of the present invention is a wavelength conversion member having a wavelength conversion layer including quantum dots that are excited by excitation light to emit fluorescence. Here, the wavelength conversion layer includes a quantum dot and an oxygen transmission coefficient reducing agent, and the oxygen transmission coefficient converted per 1 mm of the thickness of the wavelength conversion layer is less than 150.0 cm 3 /m 2 /day/atm, and The transmission coefficient reducing agent is converted into per 10 parts by mass of the content of the oxygen transmission coefficient reducing agent per 100 parts by mass of the wavelength conversion layer excluding the oxygen transmission coefficient reducing agent in the wavelength conversion layer, per 1 mm of the thickness of the wavelength conversion layer. It is a compound that exhibits an oxygen permeation coefficient reduction ability that reduces the oxygen permeation coefficient by 30% or more.

Hereinafter, the wavelength conversion member will be described in more detail.

<wavelength conversion layer>

(Quantum dot)

The wavelength conversion layer includes at least one type of quantum dot, and may include two or more types of quantum dots having different light emission characteristics. Known quantum dots include quantum dot A having a light emission center wavelength in a wavelength range of 600 nm to 680 nm, quantum dot B having a light emission center wavelength in a wavelength range of 500 nm to 600 nm, and 400 nm to 500 nm. There is a quantum dot C having an emission center wavelength in the wavelength band of nm. Quantum dot A is excited by excitation light to emit red light, quantum dot B emits green light, and quantum dot C emits blue light. For example, when blue light is incident on a wavelength conversion layer including quantum dot A and quantum dot B as excitation light, red light emitted by quantum dot A, green light emitted by quantum dot B, and wavelength conversion layer are transmitted. With one blue light, white light can be realized. Alternatively, red light emitted by quantum dot A, green light emitted by quantum dot B, and quantum dot C by injecting ultraviolet light as excitation light into a wavelength conversion layer including quantum dots A, B, and C. White light can be realized by the blue light emitted by the. As quantum dots, those prepared by known methods and commercially available products can be used without any limitation. Regarding the quantum dot, for example, Japanese Unexamined Patent Application Publication No. 2012-169271, paragraphs 0060 to 0066 can be referred to, but the present invention is not limited thereto. The emission wavelength of the quantum dot can usually be adjusted by the composition, size, and composition and size of the particles.

The quantum dots may be added to the composition for forming a wavelength conversion layer in the form of particles, or may be added in the form of a dispersion liquid dispersed in a solvent. Addition in the form of a dispersion is preferable from the viewpoint of suppressing agglomeration of the particles of quantum dots. The solvent used here is not particularly limited. Quantum dots can be added, for example, about 0.01 to 10 parts by mass per 100 parts by mass of the total amount of the composition for forming a wavelength conversion layer.

A specific aspect of wavelength conversion in a wavelength conversion member having a wavelength conversion layer including the above quantum dots will be described below with reference to the drawings. However, this invention is not limited to the following specific aspect.

1 is an explanatory diagram of an example of a backlight unit 1 including a wavelength conversion member according to an aspect of the present invention. In FIG. 1, the backlight unit 1 includes a light source 1A and a light guide plate 1B used as a surface light source. In the example shown in Fig. 1A, the wavelength conversion member is disposed on the path of light emitted from the light guide plate. On the other hand, in the example shown in Fig. 1(b), the wavelength conversion member is disposed between the light guide plate and the light source.

And in the example shown in Fig. 1(a), light emitted from the light guide plate 1B enters the wavelength conversion member 1C. In the example shown in Fig. 1(a), the light 2 emitted from the light source 1A disposed at the edge of the light guide plate 1B is blue light, and from the surface of the light guide plate 1B on the liquid crystal cell (not shown) side. It is emitted toward the liquid crystal cell. In the wavelength conversion member 1C disposed on the path of light (blue light 2) emitted from the light guide plate 1B, quantum dots A are excited by blue light 2 to emit red light 4, and blue light ( It contains at least the quantum dot B which is excited by 2) and emits green light 3. In this way, the excited green light 3 and the red light 4 and the blue light 2 transmitted through the wavelength conversion member 1C are emitted from the backlight unit 1. In this way, red light, green light, and blue light can be emitted to realize white light.

The example shown in FIG. 1(b) is the same as the mode shown in FIG. 1(a) except that the arrangement of the wavelength conversion member and the light guide plate is different. In the example shown in Fig. 1(b), excited green light 3 and red light 4, and blue light 2 transmitted through the wavelength conversion member 1C are emitted from the wavelength conversion member 1C and incident on the light guide plate. And a surface light source is realized.

(matrix)

In the wavelength conversion layer, the quantum dots are usually contained in a matrix. Here, the matrix refers to a portion of the wavelength conversion layer excluding quantum dots and an oxygen transmission coefficient reducing agent described later. The matrix is, for example, a polymer obtained by polymerizing a polymerizable composition by light irradiation or the like. The shape of the wavelength conversion layer is not particularly limited. For example, the wavelength conversion layer and the wavelength conversion member including this layer are in the form of a sheet or a film.

The polymerizable compound used for preparing the polymerizable composition is not particularly limited. One type of polymerizable compound may be used, or two or more types may be mixed and used. The content of the prepolymerizable compound to the total amount of the polymerizable composition is preferably about 10 to 99.99% by mass. As an example of a preferred polymerizable compound, from the viewpoint of transparency and adhesion of the cured film after curing, a monofunctional or polyfunctional (meth)acrylate monomer, a polymer thereof, or a polyfunctional (meth)acrylate compound such as a prepolymer. Can be mentioned. In addition, in this invention and this specification, the description of "(meth)acrylate" shall be used by the meaning of at least one of an acrylate and a methacrylate, or any one. The same applies to "(meth)acryloyl" and the like.

Examples of monofunctional (meth)acrylate compounds include acrylic acid and methacrylic acid, their derivatives, and more specifically, compounds having one polymerizable unsaturated bond ((meth)acryloyl group) of (meth)acrylic acid in a molecule. I can. Although the following compounds are mentioned as a specific example of these, this invention is not limited to this.

Methyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, n-octyl (meth) acrylate , An alkyl (meth)acrylate having 1 to 30 carbon atoms in an alkyl group such as lauryl (meth)acrylate and stearyl (meth)acrylate; Aralkyl (meth)acrylate having 7 to 20 carbon atoms of an aralkyl group such as benzyl (meth)acrylate; Alkoxyalkyl (meth)acrylates having 2 to 30 carbon atoms in an alkoxyalkyl group such as butoxyethyl (meth)acrylate; Aminoalkyl (meth)acrylates having 1 to 20 carbon atoms in total (monoalkyl or dialkyl) aminoalkyl groups such as N,N-dimethylaminoethyl (meth)acrylate; (Meth)acrylate of diethylene glycol ethyl ether, (meth) acrylate of triethylene glycol butyl ether, (meth) acrylate of tetraethylene glycol monomethyl ether, (meth) acrylate of hexaethylene glycol monomethyl ether, Monomethyl ether (meth)acrylate of octaethylene glycol, monomethyl ether (meth)acrylate of nonaethylene glycol, monomethyl ether (meth)acrylate of dipropylene glycol, monomethyl ether (meth)acrylic of heptapropylene glycol (Meth)acrylates of polyalkylene glycol alkyl ethers having 1 to 10 carbon atoms in the alkylene chain and 1 to 10 carbon atoms in the terminal alkyl ether, such as monoethyl ether (meth)acrylate of tetraethylene glycol; (Meth)acrylates of polyalkylene glycol aryl ethers having 1 to 30 carbon atoms in the alkylene chain and 6 to 20 carbon atoms in the terminal aryl ether, such as (meth)acrylate of hexaethylene glycol phenyl ether; Cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, isobornyl (meth) acrylate, methylene oxide-added cyclodecatriene (meth) acrylate having an alicyclic structure having a total carbon number of 4 to 30 (Meth)acrylate; Fluorinated alkyl (meth)acrylates having 4 to 30 carbon atoms, such as heptadecafluorodecyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, triethylene glycol mono (meth) acrylate, tetraethylene glycol mono (meth) ) (Meth)acrylate having a hydroxyl group such as acrylate, hexaethylene glycol mono(meth)acrylate, octapropylene glycol mono(meth)acrylate, and mono or di(meth)acrylate of glycerol; (Meth)acrylates having a glycidyl group such as glycidyl (meth)acrylate; Polyethylene glycol mono(meth)acrylate having 1 to 30 carbon atoms in the alkylene chain, such as tetraethylene glycol mono(meth)acrylate, hexaethylene glycol mono(meth)acrylate, and octapropylene glycol mono(meth)acrylate; (Meth)acrylamides such as (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, 2-hydroxyethyl (meth)acrylamide, and acryloylmorpholine And the like.

As the monofunctional (meth)acrylate compound, it is preferable to use an alkyl (meth)acrylate having 4 to 30 carbon atoms, and to use an alkyl (meth)acrylate having 12 to 22 carbon atoms, dispersibility of quantum dots. From the viewpoint of improvement, it is more preferable. As the dispersibility of the quantum dots increases, the amount of light that passes directly from the wavelength conversion layer to the emission surface increases, which is effective in improving the front luminance and the front contrast. Specifically, as a monofunctional (meth)acrylate compound, butyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, oleyl (meth)acrylate, stearyl (meth)acrylic Rate, behenyl (meth)acrylate, butyl (meth)acrylamide, octyl (meth)acrylamide, lauryl (meth)acrylamide, oleyl (meth)acrylamide, stearyl (meth)acrylamide, behenyl (Meth)acrylamide and the like are preferred. Among them, lauryl (meth)acrylate, oleyl (meth)acrylate, and stearyl (meth)acrylate are particularly preferred.

In addition, as a monofunctional (meth)acrylate compound, a group having at least one group selected from the group consisting of a hydroxy group and an aryl group from the viewpoint of further reduction of the oxygen transmission coefficient of the wavelength conversion layer or improvement of adhesion with other layers or members It is also preferable to use a functional (meth)acrylate compound.

As a group which the monofunctional (meth)acrylate compound has, a hydroxy group and a phenyl group are preferable. Preferred specific compounds include benzyl acrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, 1,4-cyclohexanedimethanol monoacrylate, 2-hydroxy-3-phenoxypropyl acrylate, and 4-hydroxy Roxybutyl acrylate is mentioned.

A polyfunctional (meth)acrylate compound having two or more (meth)acryloyl groups in a molecule with a monomer having one polymerizable unsaturated bond ((meth)acryloyl group) of the (meth)acrylic acid in a molecule You can also use together. As a specific example, although a compound is mentioned below, this invention is not limited to this.

Alkylene having 1 to 20 carbon atoms in an alkylene chain such as 1,4-butanedioldi(meth)acrylate, 1,6-hexanedioldi(meth)acrylate, and 1,9-nonanedioldi(meth)acrylate Glycol di(meth)acrylate; Polyalkylene glycol di(meth)acrylate having 1 to 20 carbon atoms in the alkylene chain such as polyethylene glycol di(meth)acrylate and polypropylene glycol di(meth)acrylate; Tri(meth)acrylates having a total carbon number of 10 to 60, such as trimethylolpropane tri(meth)acrylate and ethylene oxide-added trimethylolpropane tri(meth)acrylate; Tetra(meth)acrylate having a total carbon number of 10 to 100, such as ethylene oxide-added pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and pentaerythritol tetra(meth)acrylate; Dipentaerythritol hexa(meth)acrylate, etc. are mentioned.

The amount of polyfunctional (meth)acrylate monomer, such as bifunctional or trifunctional, is preferably 5 parts by mass or more from the viewpoint of coating film strength with respect to 100 parts by mass of the total amount of the polymerizable compound contained in the polymerizable composition. And, from the viewpoint of suppressing gelation of the composition, it is preferable to set it as 95 parts by mass or less. In addition, from the same viewpoint, the amount of monofunctional (meth)acrylate compound used is preferably 5 parts by mass or more and 95 parts by mass or less with respect to 100 parts by mass of the total amount of the polymerizable compound contained in the polymerizable composition.

As a preferred polymerizable compound, a compound having a cyclic group such as a ring-opening polymerizable cyclic ether group such as an epoxy group and an oxetanyl group may be mentioned. As such a compound, more preferably, a compound (epoxy compound) having an epoxy group is exemplified.

Examples of the epoxy compound include alicyclic epoxy compounds, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F di Glycidyl ether, brominated bisphenol S diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 1,4-butanediol Diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether; Polyglycidyl ethers of polyether polyols obtained by adding one or more alkylene oxides to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin; Diglycidyl esters of aliphatic long-chain dibasic acids; Monoglycidyl ethers of aliphatic higher alcohols; Monoglycidyl ethers of phenol, cresol, butylphenol, or polyether alcohols obtained by adding alkylene oxide to these; Glycidyl esters of higher fatty acids, etc. can be illustrated.

Examples of the epoxy compound include polyglycidyl esters of polybasic acids, polyglycidyl ethers of polyhydric alcohols, polyglycidyl ethers of polyoxyalkylene glycols, polyglycidyl ethers of aromatic polyols, and aromatic polyols. Hydrogenated compounds of polyglycidyl ethers, urethane polyepoxy compounds, and epoxidized polybutadienes.

Among these components, alicyclic epoxy compounds, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, 1,4-butanediol di Glycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, neopentyl glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene Glycol diglycidyl ether is preferred.

Commercially available products that can be suitably used as a glycidyl group-containing compound include UVR-6216 (manufactured by Union Carbide), glycidol, AOEX24, Saikuroma A200 (above, manufactured by Daicel Chemical Industries, Ltd.), Epicoat 828, and Epicoat 812. , Epicoat 1031, Epicoat 872, Epicoat CT508 (above, manufactured by Yucca Shell), KRM-2400, KRM-2410, KRM-2408, KRM-2490, KRM-2720, KRM-2750 (above, manufactured by Asahi Denka High School) ) And the like. These can be used alone or in combination of two or more.

In addition, these epoxy compounds are regardless of the manufacturing method. For example, Maruzen KK Publishing, 4th Edition Experimental Chemistry Lecture 20 Organic Synthesis II, 213~, 1992, Ed. by Alfred Hasfner, The chemistry of heterocyclic compounds-Small Ring Heterocycles part3 Oxiranes, John & Wiley and Sons, An Interscience Publication, New York, 1985, Yoshimura, Adhesion, Vol. 29, No. 12, 32, 1985, Yoshimura, Adhesion, Vol. 30 5, 42, 1986, Yoshimura, Adhesion, Vol. 30, No. 7, 42, 1986, Japanese Patent Laid-Open No. 11-100378, Japanese Patent No. 2906245, Japanese Patent No. 2926262, etc. It can be synthesized by

The polymerizable composition may contain a known radical polymerization initiator or cationic polymerization initiator as a polymerization initiator. For the polymerization initiator, for example, Japanese Patent Application Laid-Open No. 2013-043382, paragraph 0037, and Japanese Patent Application No. 2011-159924, paragraphs 0040 to 042 can be referred to. The polymerization initiator is preferably 0.1 mol% or more, and more preferably 0.5 to 5 mol% of the total amount of the polymerizable compound contained in the polymerizable composition.

(Oxygen permeation coefficient reducing agent)

A wavelength conversion member according to an aspect of the present invention includes an oxygen transmission coefficient reducing agent in the wavelength conversion layer including the quantum dots described above. The oxygen permeation coefficient reducing agent is a compound having the above-described oxygen permeation coefficient reducing ability. Therefore, according to the oxygen transmission coefficient reducing agent, the oxygen transmission coefficient converted to the thickness of the wavelength conversion layer of 1 mm, that is, the oxygen transmission coefficient per unit thickness of 1 mm, when 10 parts by mass of the oxygen transmission coefficient reducing agent is added, that is, the wavelength conversion. As the oxygen permeation coefficient reduction rate per 10 parts by mass of the oxygen permeation coefficient reducing agent content per 100 parts by mass of the layer excluding the oxygen permeation coefficient reducing agent, it can be reduced by 30% or more. In addition, the oxygen transmission coefficient reduction rate is defined as per 10 parts by mass of the oxygen transmission coefficient reduction agent content as described above, but the content of the oxygen transmission coefficient reduction agent in the wavelength conversion layer of the wavelength conversion member according to an aspect of the present invention Silver is not limited to 10 parts by mass. In the following, unless otherwise specified, the oxygen permeation coefficient is an oxygen permeation coefficient converted to a thickness of 1 mm. The oxygen permeation coefficient can be measured by a known method. For an example of the measurement method, reference may be made to Examples described later. And the above oxygen permeation coefficient reduction rate can be calculated by the following method 1 or method 2.

Method 1: The wavelength conversion layer (measurement target layer) containing 10 parts by mass of the oxygen transmission coefficient reducing agent per 100 parts by mass of the wavelength conversion layer excluding the oxygen transmission coefficient reducing agent, and the point not including the oxygen transmission coefficient reducing agent Except for the above, the oxygen transmission coefficient of the same wavelength conversion layer (reference layer) is measured and converted into a value per 1 mm of thickness. From the oxygen permeation coefficient thus obtained, the oxygen permeation coefficient reduction rate is calculated by the following equation.

Oxygen permeation coefficient reduction rate = [(oxygen permeation coefficient of reference layer-oxygen permeation coefficient of measurement target layer)/(oxygen permeation coefficient of reference layer)] × 100

Method 2: A reference sample formed from the same composition as the quantum dot-containing composition used for forming the wavelength conversion layer, except for the oxygen transmission coefficient reducing agent, and the composition used for preparing the reference sample, by mass of the composition: 100 parts by mass For the sample to be measured formed from a composition to which 10 parts by mass of an oxygen permeation coefficient reducing agent was added, the oxygen permeation coefficient was measured and converted into a value per 1 mm of thickness. From the oxygen permeation coefficient thus obtained, the oxygen permeation coefficient reduction rate is calculated by the following equation. In addition, the sample may have an arbitrary shape such as a sheet form or a film form.

Oxygen permeation coefficient reduction rate = [(oxygen permeation coefficient of reference sample-oxygen permeation coefficient of sample to be measured)/(oxygen permeation coefficient of reference sample)] × 100

The oxygen permeation coefficient reduction rate of the oxygen permeation coefficient reducing agent, as described above, is 30% or more, preferably 40% or more, more preferably 45% or more, further preferably 50% or more, and further It is preferably more than 50%. The oxygen permeation coefficient reduction rate is, for example, 90% or less, 80% or less, or 70% or less, but the upper limit is not particularly limited because it is more preferable.

The oxygen permeation coefficient reducing agent is not particularly limited as long as it has the above oxygen permeation coefficient reducing ability. Although not limited to the following, preferred embodiments of the compound used as an oxygen permeation reducing agent include those having a cyclic structure, a relatively long chain, for example, a linear or branched alkyl group having 10 to 20 carbon atoms. have. As a specific example, a biphenyl compound, a hydrogenated biphenyl compound, a terphenyl compound, a bisphenol compound, a hydrogenated bisphenol compound, a trityl compound, a hydrogenated trityl compound, a rosin compound, a novolac compound, a cardo compound, a benzophenone compound, a phenyl ether compound And at least one compound selected from the group consisting of dialkyl ketone compounds. In addition, as bisphenol compounds, bisphenol A type, bisphenol B type, bisphenol C type, bisphenol E type, bisphenol F type, bisphenol G type, bisphenol M type, bisphenol S type, bisphenol P type, bisphenol T type, bisphenol Z type compound, etc. Can be mentioned. Only one type of oxygen permeation coefficient reducing agent may be used, or two or more types thereof may be used in combination.

In one embodiment, a compound having a relatively small molecular weight tends to have a good oxygen permeation coefficient reducing ability. In this regard, the present inventors speculate whether or not the thing that is easy to enter the gap of the matrix contributes, but it is a speculation to the last, and the present invention is not limited in any way. The molecular weight is preferably 2000 or less, more preferably 1000 or less, further preferably 500 or less, and even more preferably 300 or less. The molecular weight is, for example, 100 or more, but the lower limit is not particularly limited. In addition, the molecular weight in the case where the oxygen permeation coefficient reducing agent is a polymer containing a repeating unit refers to a weight average molecular weight. In addition, in one embodiment, the oxygen permeation coefficient reducing agent may not have a polymerizable functional group in the molecule. Here, the polymerizable functional group refers to a functional group capable of causing a polymerization reaction by polymerization treatment such as light irradiation or heating.

The weight average molecular weight in the present invention and the present specification is a value obtained by converting a measured value by gel permeation chromatography (GPC) in terms of polystyrene. As an example of specific measurement conditions of the weight average molecular weight, the following measurement conditions are mentioned. The weight average molecular weight described in Examples described later is a value measured under the following conditions.

GPC device: HLC-8120 (manufactured by Tosoh Corporation):

Column: TSK gel Multipore HXL-M (Tosoh Corporation 7.8 mm ID (inner diameter) x 30.0 cm)

Eluent: Tetrahydrofuran (THF)

As the oxygen permeation coefficient reducing agent, more specifically, the following compounds can be illustrated. In addition, in the present invention and the specification of the present application, a "group" such as an alkyl group may or may not have a substituent unless specifically described. In addition, the number of carbon atoms in the case of a group in which the number of carbon atoms is described means the number including the number of carbon atoms that the substituent has. When any group has a substituent, examples of the substituent include an alkyl group (e.g., an alkyl group having 1 to 6 carbon atoms), a hydroxyl group, an alkoxy group (e.g., an alkoxy group having 1 to 6 carbon atoms), and a halogen atom (e.g., a fluorine atom or chlorine). Atom, bromine atom), a cyano group, an amino group, a nitro group, an acyl group, and a carboxyl group.

The alkyl group described below is a linear or branched alkyl group, or a cycloalkyl group is also included unless specifically described. Except for the general formula 12 described below, examples of the alkyl group include preferably an alkyl group having 1 to 5 carbon atoms, more preferably 1 to 3, and still more preferably 1 or 2. On the other hand, with respect to the following general formula 12, as the alkyl group, preferably, an alkyl group having 10 to 20 carbon atoms, more preferably 12 to 20 carbon atoms, and still more preferably 15 to 20 carbon atoms is exemplified.

The acyl group described below is represented by R(C=O)-, and R is an alkyl group.

The acyloxy group described below is represented by R(C=O)-O-, and R is a linear or branched alkyl group or a cycloalkyl group.

The details of the alkyl group represented by R of the acyl group and the linear or branched alkyl group represented by R of the acyloxy group are as described for the general formula except for the above general formula 12. About the cycloalkyl group represented by R of an acyloxy group, a cyclohexyl group is mentioned preferably.

The alkyloxy group described below is represented by R-O-, and R is an alkyl group. The details of the alkyl group are as described above for the general formula except for the general formula 12 described later.

The phenylalkylene group described below is represented by Ph-X-, Ph is a phenyl group, and X is an alkylene group. The alkylene group is preferably a linear or branched C1-C6 alkylene group, and an example is a dimethylmethylene group (-C(CH ₃ ) ₂ -).

In General Formula 1, R ¹⁰¹ to ^{R 110} each independently represent a hydrogen atom, an alkyl group, an acyl group, an alkyloxy group, or a hydroxy group. From the viewpoint of the rate of reduction of the oxygen permeation coefficient, ^{at least one of R 101} to ^{R 110} preferably represents a group other than a hydrogen atom, more preferably a hydroxy group, more preferably one or two hydroxy groups, It is even more preferable that two represent a hydroxy group.

In General Formula 2, R ²⁰¹ to ^{R 211} each independently represent a hydrogen atom, an alkyl group, an acyl group, an alkyloxy group, a hydroxy group, a phenyl group, or a cyano group. From the viewpoint of the rate of reduction of the oxygen permeation coefficient ^{, at least one of R 201} to ^{R 211} preferably represents a group other than a hydrogen atom, and more preferably represents a hydroxy group. In addition, in General Formula 2, the ^{bonding position of the other two benzene rings to the benzene ring having -(R 206} ) ₄ may be any one of an ortho position, a meta position, and a para position, preferably a para position. In addition, in -(R ²⁰⁶ ) ₄ , four R ²⁰⁶ may be the same or different from each other.

In General Formula 3, R ³⁰¹ to ^{R 312} each independently represent a hydrogen atom, an alkyl group, an acyl group, an alkyloxy group, a hydroxy group, a phenyl group, or a phenylalkylene group. It is preferable that at least one of R ³⁰¹ to ^{R 312} represents a group other than a hydrogen atom. R ³¹¹ and R ³¹² may each independently represent an alkyl group or a phenyl group, or may be linked to form a cycloalkane ring. As the cycloalkane ring, a substituted or unsubstituted cyclohexane ring is preferable, and a substituted cyclohexane ring is preferable. As the substituent, an alkyl group is preferable, and a methyl group is particularly preferable. From the viewpoint of the rate of reduction of the oxygen permeation coefficient, ^{it is preferable that at least one of R 301} to ^{R 310} is a hydroxy group, an alkyloxy group (more preferably a methoxy group), or a phenylalkylene group.

In General Formula 4, R ⁴⁰¹ to ^{R 412} each independently represent a hydrogen atom, an alkyl group, an acyl group, an acyloxy group, an alkyloxy group, a hydroxy group, or a phenyl group. From the viewpoint of the rate of reduction of the oxygen permeation coefficient ^{, it is preferable that at least one of R 401} to ^{R 412} represents a group other than a hydrogen atom, and more preferably a hydroxy group.

In formula 5, R ⁵⁰¹ ~R ⁵¹⁰ are, each independently represent a hydrogen atom, an alkyl group, an acyl group, an acyloxy group, alkyloxy group, or a hydroxyl group. From the viewpoint of the rate of reduction of the oxygen permeation coefficient, ^{at least one of R 501} to ^{R 510} preferably represents a group other than a hydrogen atom, more preferably a hydroxy group, and still more preferably two of the hydroxy groups.

In General Formula 6, R ⁶⁰¹ to ^{R 610} each independently represent a hydrogen atom, an alkyl group, an acyl group, an acyloxy group, an alkyloxy group, or a hydroxy group. From the viewpoint of the reduction rate of the oxygen permeation coefficient, ^{at least one of R 601} to ^{R 610} preferably represents a group other than a hydrogen atom, more preferably an alkyloxy group, more preferably two of the alkyloxy groups, and the above It is even more preferable that the alkyloxy group represents a methoxy group.

In the general formula 7, R ⁷⁰¹ ~R ⁷¹² comprise, each independently, represent a hydrogen atom, an alkyl group, an acyl group, an alkyloxy group, a hydroxy group, or a phenyl group. From the viewpoint of the oxygen permeation coefficient Reduction rate, at least one of R ⁷⁰¹ ~R ⁷¹² is more preferably represents a desirable, and represents a hydroxy group other than a hydrogen atom.

In General Formulas 8a and 8b, R ⁸⁰¹ to ^{R 813} each independently represent a hydrogen atom, an alkyl group, an acyl group, an alkyloxy group, a hydroxy group, a carboxyl group, or a phenyl group. From the viewpoint of the rate of reduction of the oxygen permeation coefficient ^{, it is preferable that at least one of R 801} to ^{R 813} represents a group other than a hydrogen atom, and more preferably a carboxyl group. Specific examples of commercial products include, for example, Longis R, Longis K-25, Longis K-80, and Longis K-18 (all of the above are brand names, rosin derivatives, manufactured by Arakawa Chemical Industry Co., Ltd.) Fine Crystal KR-85, Fine Crystal KR-120, Fine Crystal KR-612, Fine Crystal KR-614, Fine Crystal KE-100, Fine Crystal KE-311, Fine Crystal KE-359, Fine Crystal KE-604, Fine Crystal 30PX, Fine Crystal D-6011 , Fine Crystal D-6154, Fine Crystal D-6240, Fine Crystal KM-1500, Fine Crystal KM-1550 (all above are brand names, super pale rosin derivatives, manufactured by Arakawa Chemical Industry Co., Ltd.), Aradamu R-140, Ardaimu No R-95 (all above are brand names, polymerized rosin, manufactured by Arakawa Chemical Industry Co., Ltd.), Hyperic CH (all above are brand names, hydrogenated rosin, manufactured by Arakawa Chemical Industry Co., Ltd.), Beamset 101 (all above are brand names, rosin acrylate Arakawa Chemical Industry Co., Ltd.), and the like.

In General Formula 9, R ⁹⁰¹ and R ⁹⁰² each independently represent a hydrogen atom, an alkyl group, an acyl group, an alkyloxy group, a hydroxy group, or a phenyl group, and at least one preferably represents a group other than a hydrogen atom group. In General Formula 9, * represents a bonding position with an adjacent structure.

In the novolac compound having a structural unit represented by General Formula 9, the number of the structural units is 2 or more, for example, in the range of 2 to 10. ^{R 901} and R ⁹⁰² in the structural units present in a plurality of molecules in one molecule may be different or the same in each structural unit. From the viewpoint of the oxygen permeation coefficient Reduction rate, at least one of R ^901, R ⁹⁰² of the at least one structural unit with at least one of R ^901, R ⁹⁰² in a desirable, and at least two structural units of the hydroxy group It is more preferable that it is a hydroxy group, and in all structural units, it is more preferable that at least one of ^{R 901} and R ^{902 is a hydroxy group.}

In General Formula 10, R ¹⁰⁰¹ to ^{R 1014} each independently represent a hydrogen atom, an alkyl group, an acyl group, an alkyloxy group, a hydroxy group, or a phenyl group. From the viewpoint of the rate of reduction of the oxygen permeation coefficient ^{, it is preferable that at least one of R 1001} to ^{R 1014} represents a group other than a hydrogen atom, and more preferably a hydroxy group.

In General Formula 11, R ¹¹⁰¹ to ^{R 1110} each independently represent a hydrogen atom, an alkyl group, an acyl group, an alkyloxy group, a hydroxy group, or a phenyl group. From the viewpoint of the rate of reduction of the oxygen permeation coefficient, ^{at least one of R 1101} to ^{R 1110} preferably represents a group other than a hydrogen atom, and more preferably represents a hydroxy group.

R ¹²⁰¹ and R ¹²⁰² each independently represent an alkyl group. The details of the alkyl group are as described above. As a specific example of a preferable compound, pelargon, lauron, stearone, etc. are mentioned.

Hereinafter, specific examples of the compounds usable as an oxygen permeation coefficient reducing agent are shown, but the present invention is not limited to the following specific examples.

The oxygen permeation coefficient reducing agent described above can be synthesized by a known method, and can also be obtained as a commercial item.

The oxygen transmission coefficient reducing agent is an oxygen transmission coefficient obtained by converting the oxygen transmission coefficient of the wavelength conversion layer containing this agent per 1 mm of thickness, and converts the wavelength to an amount that can be less than 150.0 cm 3 /m 2 /day/atm. It is preferable to contain it in the layer. In this respect, the preferred content is in the range of 1 to 50 parts by mass, more preferably in the range of 1 to 30 parts by mass, and still more preferably in the range of 1 to 20 parts by mass.

(Optional ingredient)

The wavelength conversion layer may optionally contain one or more components in addition to the components described above. As an example of such an arbitrary component, light-scattering particles are mentioned. Here, the "light scattering particle" refers to a particle having a particle size of 0.10 µm or more. The scattering of light is caused by optical non-uniformity within the layer. Particles with a sufficiently small particle size do not significantly reduce the optical uniformity of the layer even if the particles are included, whereas particles with a particle size of 0.10 µm or more make the layer optically non-uniform, thereby reducing light scattering. It is a particle that can result. It is preferable from the viewpoint of brightness improvement that light-scattering particles are contained in the wavelength conversion layer.

The particle size described above is a value obtained by observing with a scanning electron microscope (SEM). Specifically, after photographing a cross section of the wavelength conversion layer at a magnification of 5000 times, the primary particle diameter is measured from the obtained image. In addition, for particles that are not spherical, the average value of the length of the major axis and the length of the minor axis is calculated, and this is adopted as the primary particle diameter. The primary particle diameter thus obtained is taken as the particle size of the particles. In addition, the average particle size of the light-scattering particles is an arithmetic average of the particle sizes of 20 particles randomly extracted from particles having a particle size of 0.10 µm or more in the above photographed image. In addition, the average particle size of the light-scattering particles shown in Examples to be described later is a value obtained by observing and measuring the cross section of the wavelength conversion layer using S-3400N manufactured by Hitachi Hi-Tech as a scanning electron microscope.

As described above, the particle size of the light scattering particles is 0.10 µm or more. From the viewpoint of the light-scattering effect, the particle size of the light-scattering particles is preferably in the range of 0.10 to 15.0 µm, more preferably in the range of 0.10 to 10.0 µm, and still more preferably in the range of 0.20 to 4.0 µm. Further, in order to improve higher luminance or adjust the distribution of luminance with respect to the viewing angle, two or more types of light-scattering particles having different particle sizes may be mixed and used.

The light scattering particles may be organic particles, inorganic particles, or organic-inorganic composite particles. Examples of the organic particles include synthetic resin particles. Specific examples include silicone resin particles, acrylic resin particles (polymethyl methacrylate (PMMA)), nylon resin particles, styrene resin particles, polyethylene particles, urethane resin particles, benzoguanamine particles, and the like. From the viewpoint of the light scattering effect, the refractive index of the light-scattering particles and other parts in the matrix of the wavelength conversion layer are preferably different, and from the viewpoint of the availability of particles having a suitable refractive index, silicone resin particles and acrylic resin particles are preferable. Do. In addition, particles having a hollow structure can also be used. In addition, as inorganic particles, particles such as diamond, titanium oxide, zirconium oxide, lead oxide, lead carbonate, zinc oxide, zinc sulfide, antimony oxide, silicon oxide, and aluminum oxide can be used. Titanium oxide and aluminum oxide are preferable from the viewpoint of easiness.

Light-scattering particles are those contained in the wavelength conversion layer at least 0.2% by volume based on the total volume of the wavelength conversion layer as 100% by volume from the viewpoint of the light-scattering effect and the brittleness of the wavelength conversion layer containing the particles. It is preferable, it is more preferable that it contains 0.2 volume%-50 volume%, It is more preferable that it contains 0.2 volume%-30 volume%, It is still more preferable that it contains 0.2 volume%-10 volume%.

In order to adjust the refractive index of the portion of the matrix excluding the light-scattering particles, particles having a smaller particle size than the light-scattering particles can be used as the refractive index adjusting particles. The particle size of the refractive index adjustment particles is less than 0.10 µm.

Examples of the refractive index adjusting particles include particles such as diamond, titanium oxide, zirconium oxide, lead oxide, lead carbonate, zinc oxide, zinc sulfide, antimony oxide, silicon oxide, and aluminum oxide. As for the refractive index adjusting particles, an amount capable of adjusting the refractive index may be used, and the content in the wavelength conversion layer is not particularly limited.

<Oxygen permeation coefficient of the wavelength conversion layer>

The oxygen transmission coefficient converted per 1 mm of the thickness of the wavelength conversion layer is less than 150.0 cm 3 /m 2 /day/atm as described above. In addition, the unit "cm 3 /m 2 /day/atm" can also be described as "cm 3 /(m 2 ·day·atm)". In the case of the wavelength conversion layer in which oxygen transmission is suppressed in this manner, for example, even when the side surface of the wavelength conversion layer is exposed to air, a decrease in luminous efficiency at the side end portion of the wavelength conversion layer can be suppressed. The present inventors speculate that this is due to the fact that the layer itself of the wavelength conversion layer is difficult to transmit oxygen, so that the invasion of oxygen from the side surface can be suppressed. The oxygen permeation coefficient converted per 1 mm of the thickness of the wavelength conversion layer is preferably 100.0 cm 3 /m 2 /day/atm or less, more preferably 50.0 cm 3 /m 2 /day/atm or less. On the other hand, the lower limit is, for example, 0.0001 cm 3 /m 2 /day/atm or more or 0.001 cm 3 /m 2 /day/atm or more. It is not.

<Method of forming a wavelength conversion layer>

As long as the wavelength conversion layer is a layer containing the components described above and a known additive that can be optionally added, the formation method is not particularly limited. After applying a quantum dot-containing polymerizable composition (composition for forming a wavelength conversion layer) prepared by simultaneously or sequentially mixing the components described above and one or more known additives added as necessary on a suitable substrate, irradiation with light By performing polymerization treatment such as heating and polymerization and curing, a wavelength conversion layer containing quantum dots and an oxygen transmission coefficient reducing agent can be formed in the matrix. Here, as an example of a known additive, for example, a silane coupling agent capable of improving adhesion to an adjacent layer can be mentioned. As the silane coupling agent, a known one can be used without any limitation. As a preferable silane coupling agent from the viewpoint of adhesion, a silane coupling agent represented by General Formula (1) described in Japanese Unexamined Patent Application Publication No. 2013-43382 can be mentioned. For details, reference can be made to the description of Japanese Unexamined Patent Application Publication No. 2013-43382, paragraphs 0011 to 0016. The amount of additives, such as a silane coupling agent, is not particularly limited and can be appropriately set. Further, for the viscosity of the quantum dot polymerizable composition, etc., a solvent may be added as necessary. The kind and amount of the solvent used in this case are not particularly limited. For example, as a solvent, an organic solvent may be used alone or in combination of two or more.

As an application method, known coating methods such as curtain coating method, dip coating method, spin coating method, printing coating method, spray coating method, slot coating method, roll coating method, slide coating method, blade coating method, gravure coating method, wire bar method, etc. There is a method. In addition, curing conditions can be appropriately set according to the kind of the polymerizable compound to be used or the composition of the polymerizable composition. In addition, when the quantum dot-containing polymerizable composition is a composition containing a solvent, before performing the polymerization treatment, a drying treatment may be performed in order to remove the solvent.

The polymerization treatment of the quantum dot-containing polymerizable composition can be performed while the composition is sandwiched between two substrates. An aspect of the manufacturing process of the wavelength conversion member including such a polymerization treatment will be described below with reference to the drawings. However, this invention is not limited to the following aspect.

3 is a schematic configuration diagram of an example of a manufacturing apparatus 100 for a wavelength conversion member, and FIG. 4 is a partially enlarged view of the manufacturing apparatus shown in FIG. 3. The manufacturing process of the wavelength conversion member using the manufacturing apparatus 100 shown in FIGS. 3 and 4,

A step of forming a coating film by applying a quantum dot-containing polymerizable composition to the surface of the first substrate (hereinafter, also referred to as “first film”) to be continuously conveyed;

A process of laminating (overlapping) a second base material (hereinafter also referred to as ``second film'') to be continuously conveyed on the coating film, and holding the coating film with the first film and the second film, and

In the state where the coating film is sandwiched between the first film and the second film, any one of the first film and the second film is wound around a backup roller, light irradiated while continuously conveying, the coating film is polymerized and cured, and the wavelength conversion layer (curing At least a step of forming a layer). By using a barrier film having barrier properties to oxygen or moisture as either of the first substrate and the second substrate, a wavelength converting member in which one side is protected by the barrier film can be obtained. Further, by using a barrier film as the first substrate and the second substrate, respectively, it is possible to obtain a wavelength converting member in which both surfaces of the wavelength converting layer are protected by the barrier film.

More specifically, first, the first film 10 is continuously conveyed to the coating unit 20 from an unillustrated delivery machine. From the delivery machine, for example, the first film 10 is delivered at a conveying speed of 1 to 50 m/min. However, it is not limited to this conveyance speed. When delivered, a tension of 20 to 150 N/m, preferably 30 to 100 N/m, is applied to the first film 10, for example.

In the coating unit 20, a quantum dot-containing polymerizable composition (hereinafter, also referred to as “coating solution”) is applied to the surface of the first film 10 to be continuously conveyed, and the coating film 22 (refer to FIG. 2) is formed. Is formed. In the coating unit 20, for example, a die coater 24 and a backup roller 26 disposed opposite to the die coater 24 are provided. The coating liquid from the discharge port of the die coater 24 on the surface of the first film 10 that is continuously conveyed by winding the surface opposite to the surface on which the coating film 22 of the first film 10 is formed is wrapped around the backup roller 26 This is applied, and the coating film 22 is formed. Here, the coating film 22 refers to a composition containing quantum dots before polymerization treatment applied on the first film 10.

In this embodiment, although the die coater 24 to which the extrusion coating method was applied was shown as the coating device, it is not limited thereto. For example, a coating apparatus to which various methods such as a curtain coating method, an extrusion coating method, a rod coating method, or a roll coating method can be used can be used.

The 1st film 10 which passed through the coating part 20 and formed the coating film 22 on it is continuously conveyed to the laminate part 30. In the laminate portion 30, the second film 50 continuously conveyed is laminated on the coating film 22, and the coating film 22 is sandwiched between the first film 10 and the second film 50.

In the laminate part 30, a laminate roller 32 and a heating chamber 34 surrounding the laminate roller 32 are provided. The heating chamber 34 is provided with an opening 36 for passing the first film 10 and an opening 38 for passing the second film 50.

A backup roller 62 is disposed at a position facing the laminate roller 32. In the first film 10 on which the coating film 22 is formed, the surface opposite to the formation surface of the coating film 22 is wound around the backup roller 62 and continuously conveyed to the lamination position P. The lamination position (P) refers to a position where the contact between the second film 50 and the coating film 22 starts. It is preferable that the first film 10 is wound around the backup roller 62 before reaching the lamination position P. This is because even when wrinkles occur in the first film 10, the wrinkles are corrected and removed by the backup roller 62 until they reach the lamination position P. Therefore, the distance L1 between the position (contact position) and the laminate position P where the first film 10 is wound around the backup roller 62 is preferably longer, and, for example, 30 mm or more is preferable. And, the upper limit value is usually determined by the diameter of the backup roller 62 and the pass line.

In this embodiment, the second film 50 is laminated by the backup roller 62 and the lamination roller 32 used in the polymerization treatment unit 60. In other words, the backup roller 62 used in the polymerization treatment unit 60 is also used as a roller used in the laminate unit 30. However, it is not limited to the above configuration, and a roller for lamination may be provided in the laminate part 30 separately from the backup roller 62 so that the backup roller 62 may not be used at the same time.

By using the backup roller 62 used in the polymerization treatment unit 60 in the laminate unit 30, the number of rollers can be reduced. Moreover, the backup roller 62 can also be used as a heat roller for the 1st film 10.

The second film 50 delivered from a delivery machine (not shown) is wound around the laminate roller 32 and continuously conveyed between the laminate roller 32 and the backup roller 62. The second film 50 is laminated on the coating film 22 formed on the first film 10 at the lamination position P. Accordingly, the coating film 22 is pinched by the first film 10 and the second film 50. Lamination refers to superimposing and laminating the second film 50 on the coating film 22.

The distance L2 between the laminate roller 32 and the backup roller 62 is the wavelength conversion layer (cured layer) 28 obtained by polymerizing and curing the first film 10 and the coating film 22, and the second film ( It is preferable that it is not less than the value of the total thickness of 50). In addition, it is preferable that L2 is less than or equal to the length obtained by adding 5 mm to the total thickness of the first film 10, the coating film 22, and the second film 50. By making the distance L2 less than or equal to the length obtained by adding 5 mm to the total thickness, it is possible to prevent air bubbles from entering between the second film 50 and the coating film 22. Here, the distance L2 between the laminate roller 32 and the backup roller 62 means the shortest distance between the outer peripheral surface of the laminate roller 32 and the outer peripheral surface of the backup roller 62.

The rotational accuracy of the laminate roller 32 and the backup roller 62 is 0.05 mm or less, preferably 0.01 mm or less due to radial vibration. The smaller the radial vibration, the smaller the thickness distribution of the coating film 22 can be.

In addition, in order to suppress thermal deformation after the coating film 22 is sandwiched between the first film 10 and the second film 50, the temperature of the backup roller 62 of the polymerization treatment unit 60 and the first film 10 ), and the difference between the temperature of the backup roller 62 and the temperature of the second film 50 are preferably 30° C. or less, more preferably 15° C. or less, and most preferably the same.

In order to reduce the difference with the temperature of the backup roller 62, when the heating chamber 34 is provided, heating the first film 10 and the second film 50 in the heating chamber 34 It is desirable. For example, hot air is supplied to the heating chamber 34 by a hot air generating device (not shown) to heat the first film 10 and the second film 50.

The first film 10 may be heated by the backup roller 62 by winding the first film 10 around the temperature-controlled backup roller 62.

On the other hand, about the 2nd film 50, the 2nd film 50 can be heated with the lamination roller 32 by using the lamination roller 32 as a heat roller.

However, the heating chamber 34 and the heat roller are not essential and can be provided as needed.

Next, in the state where the coating film 22 is pinched by the 1st film 10 and the 2nd film 50, it is conveyed continuously to the superposition|polymerization processing part 60. In the embodiment shown in the drawing, the polymerization treatment in the polymerization treatment unit 60 is performed by light irradiation, but in the case where the polymerizable compound contained in the quantum dot-containing polymerizable composition is polymerized by heating, warm air is blown. The polymerization treatment can be performed by heating such as air.

A light irradiation device 64 is provided at a position opposite the backup roller 62 and the backup roller 62. Between the backup roller 62 and the light irradiation device 64, the 1st film 10 and the 2nd film 50 which pinched the coating film 22 are conveyed continuously. The light irradiated by the light irradiation device may be determined in accordance with the kind of the photopolymerizable compound contained in the quantum dot-containing polymerizable composition, and an example is ultraviolet rays. Ultraviolet rays here shall mean light having a wavelength of 280 to 400 nm. As a light source for generating ultraviolet rays, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra-high pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, and the like can be used. The amount of light irradiation may be set in a range capable of advancing polymerization and curing of the coating film. For example, as an example, ultraviolet rays having an irradiation amount of 100 to 10000 mJ/cm 2 can be irradiated toward the coating film 22.

In the polymerization treatment unit 60, the first film 10 is wound around the backup roller 62 in a state where the coating film 22 is sandwiched by the first film 10 and the second film 50, and is continuously conveyed. While doing light irradiation from the light irradiation apparatus 64, the coating film 22 is hardened, and the wavelength conversion layer (cured layer) 28 can be formed.

In the present embodiment, the first film 10 side was wound around the backup roller 62 and continuously conveyed. However, the second film 50 may be wound around the backup roller 62 and continuously conveyed.

Winding around the backup roller 62 refers to a state in which one of the first film 10 and the second film 50 is in contact with the surface of the backup roller 62 at a certain lap angle. Therefore, during continuous conveyance, the first film 10 and the second film 50 move in synchronization with the rotation of the backup roller 62. It is sufficient to wind it around the backup roller 62 while it is irradiated with ultraviolet rays at least.

The backup roller 62 includes a main body having a cylindrical shape and a rotating shaft disposed at both ends of the main body. The main body of the backup roller 62 has a diameter of 200 to 1000 mm, for example. There is no limitation on the diameter φ of the backup roller 62. In consideration of curl deformation of the laminated film, equipment cost, and degree of rotation, it is preferable to have a diameter of 300 to 500 mm. By attaching a temperature controller to the main body of the backup roller 62, the temperature of the backup roller 62 can be adjusted.

The temperature of the backup roller 62 is the heat generation during light irradiation, the curing efficiency of the coating film 22, and the occurrence of wrinkle deformation on the backup roller 62 of the first film 10 and the second film 50. In consideration of, it can be decided. It is preferable to set the backup roller 62 in the temperature range of 10 to 95 degreeC, for example, and it is more preferable that it is 15 to 85 degreeC. Here, the temperature related to the roller shall mean the surface temperature of the roller.

The distance L3 between the lamination position P and the light irradiation device 64 can be, for example, 30 mm or more.

The coating film 22 becomes a cured layer 28 by light irradiation, and a wavelength conversion member 70 including the first film 10, the cured layer 28, and the second film 50 is manufactured. The wavelength conversion member 70 is peeled from the backup roller 62 by the peeling roller 80. The wavelength conversion member 70 is continuously conveyed by a winding machine (not shown), and then the wavelength conversion member 70 is wound up in a roll shape by a winding machine.

As mentioned above, although one aspect of the manufacturing process of a wavelength conversion member was demonstrated, this invention is not limited to the said aspect. For example, a quantum dot-containing composition may be applied on a substrate, and a wavelength conversion layer (cured layer) may be prepared by performing a polymerization treatment after drying treatment performed as necessary without laminating an additional substrate thereon. . One or more other layers may be laminated on the produced wavelength conversion layer by a known method.

The total thickness of the wavelength conversion layer is preferably in the range of 1 to 500 µm, more preferably in the range of 100 to 400 µm. In addition, the wavelength conversion layer may have a stacked structure of two or more layers, and may contain two or more types of quantum dots exhibiting different light emission characteristics in the same layer. When the wavelength conversion layer is a laminate of two or more layers, the thickness of one layer is preferably in the range of 1 to 300 µm, more preferably in the range of 10 to 250 µm, and still more preferably 30 to 150 µm. It is in the range of μm.

<Other layers, substrates>

The wavelength conversion member may have a configuration including only the wavelength conversion layer or a substrate described later in addition to the wavelength conversion layer. Alternatively, you may have at least one layer selected from the group consisting of an inorganic layer and an organic layer on at least one main surface of the wavelength conversion layer. As such an inorganic layer and an organic layer, an inorganic layer and an organic layer which comprise a barrier film mentioned later are mentioned. From the viewpoint of maintaining luminous efficiency, it is preferable that at least one layer selected from the group consisting of an inorganic layer and an organic layer, respectively, is included on both main surfaces of the wavelength conversion layer. This is because intrusion of oxygen from the main surface into the wavelength conversion layer can be prevented by such a layer. In addition, in one aspect, it is preferable that the inorganic layer and the organic layer are included as an adjacent layer in direct contact with the main surface of the wavelength conversion layer. Further, in another aspect, the main surface of the wavelength conversion layer and another layer may be bonded via a known adhesive layer. In one aspect, in the wavelength conversion member, the entire surface of the wavelength conversion layer may be covered with a coating (that is, even if it is sealed), but from the viewpoint of productivity, the entire surface is not covered with a coating, for example, both main surfaces are It is preferable that it is protected by another layer, preferably by a barrier film to be described later, and that the side surface is in a state exposed to the atmosphere. Even in such a state, since it is difficult for the wavelength conversion layer to pass oxygen, deterioration of the quantum dots due to oxygen can be suppressed.

(materials)

The wavelength converting member may have a base material in order to improve strength, easiness of film formation, and the like. The substrate may be in direct contact with the wavelength conversion layer. One or two or more substrates may be included in the wavelength converting member, and the wavelength converting member may have a structure in which a substrate, a wavelength converting layer, and a substrate are laminated in this order. When the wavelength conversion member includes two or more substrates, these substrates may be the same or different. It is preferable that the substrate is transparent to visible light. Here, the term "transparent with respect to visible light" means that the light transmittance in the visible region is 80% or more, preferably 85% or more. The light transmittance used as a transparent measure can be calculated by measuring the total light transmittance and the amount of scattered light using the method described in JIS-K7105, that is, an integrating sphere light transmittance measuring device, and subtracting the diffuse transmittance from the total light transmittance.

The thickness of the substrate is preferably in the range of 10 to 500 µm, particularly in the range of 20 to 400 µm, particularly in the range of 30 to 300 µm, from the viewpoints of gas barrier properties and impact resistance.

In addition, the base material may be used as either or both of the first film and the second film described above.

The substrate may be a barrier film. The barrier film is a film having a gas barrier function to block oxygen molecules. It is also preferable that the barrier film has a function of blocking water vapor.

The barrier film usually needs to include at least an inorganic layer, and may be a film including a support film and an inorganic layer. Regarding the support film, for example, Japanese Patent Application Laid-Open No. 2007-290369, paragraphs 0046 to 0052, and Japanese Patent Application Publication No. 2005-096108, paragraphs 0040 to 0055, can be referred to. The barrier film may include a barrier laminate including at least one inorganic layer and at least one organic layer on the support film. As an example, a laminated structure of a support film/organic layer/inorganic layer, a laminated structure of a support film/inorganic layer/organic layer, a laminated structure of a support film/organic layer/inorganic layer/organic layer (here, the two organic layers are of thickness and composition. One or both may be the same or different), etc. are mentioned. Laminating a plurality of layers in this way can further increase the barrier property. On the other hand, as the number of layers to be laminated increases, the light transmittance of the wavelength conversion member tends to decrease. , It is preferable to increase the number of laminations. Specifically, the barrier film preferably has an oxygen permeability of 1 cm 3 /(m 2 ·day·atm) or less. Here, the oxygen permeability is a value measured using an oxygen gas permeability measuring device (OX-TRAN 2/20 manufactured by MOCON: brand name) under conditions of a measurement temperature of 23°C and a relative humidity of 90%. In addition, it is preferable that the barrier film has a total light transmittance of 80% or more in a visible region. The visible light region refers to a wavelength range of 380 to 780 nm, and the total light transmittance refers to the average value of the light transmittance over the visible light region.

The oxygen permeability of the barrier film is more preferably 0.1 cm 3 /(m 2 ·day·atm) or less, and more preferably 0.01 cm 3 /(m 2 ·day·atm) or less. The total light transmittance in the visible region is more preferably 90% or more. The lower the oxygen transmittance is, the more preferable it is, and the higher the total light transmittance in the visible region is, the more preferable.

-Inorganic layer-

The "inorganic layer" is a layer mainly composed of an inorganic material, and is preferably a layer formed only of an inorganic material. On the other hand, the organic layer is a layer containing an organic material as a main component, and preferably refers to a layer in which the organic material occupies 50% by mass or more, 80% by mass or more, and particularly 90% by mass or more.

The inorganic material constituting the inorganic layer is not particularly limited, and for example, a metal or various inorganic compounds such as inorganic oxides, nitrides and oxynitrides can be used. As the elements constituting the inorganic material, silicon, aluminum, magnesium, titanium, tin, indium, and cerium are preferable, and one or two or more of them may be included. Specific examples of the inorganic compound include silicon oxide, silicon oxynitride, aluminum oxide, magnesium oxide, titanium oxide, tin oxide, indium oxide alloy, silicon nitride, aluminum nitride, and titanium nitride. Further, as the inorganic layer, a metal film such as an aluminum film, a silver film, a tin film, a chromium film, a nickel film, or a titanium film may be provided.

Among the above materials, silicon nitride, silicon oxide, or silicon oxynitride is particularly preferable. This is because the inorganic layer made of these materials has good adhesion to the organic layer, so that the barrier property can be further increased.

The method for forming the inorganic layer is not particularly limited, and for example, various film forming methods capable of evaporating or scattering the film-forming material to be deposited on the surface to be deposited can be used.

Examples of the method for forming the inorganic layer include a vacuum vapor deposition method in which inorganic materials such as inorganic oxide, inorganic nitride, inorganic oxynitride, and metal are heated and deposited; An oxidation reaction vapor deposition method in which an inorganic material is used as a raw material, oxidized by introducing oxygen gas, and deposited; A sputtering method in which an inorganic material is used as a target raw material, argon gas and oxygen gas are introduced and sputtered to evaporate; Plasma using an organosilicon compound as a raw material for physical vapor deposition (Physical Vapor Deposition method) such as ion plating method in which an inorganic material is heated by a plasma beam generated by a plasma gun to evaporate, or when a vapor-deposited film of silicon oxide is formed. The chemical vapor deposition method, etc. are mentioned. The vapor deposition may be performed on the surface of a support film, a wavelength conversion layer, an organic layer, or the like as a substrate.

The silicon oxide film is preferably formed using an organosilicon compound as a raw material and using a low-temperature plasma chemical vapor deposition method. As this organosilicon compound, specifically, 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, vinyltrimethylsilane, hexamethyldisilane, methylsilane, dimethylsilane, trimethylsilane, diethylsilane, Propylsilane, phenylsilane, vinyl triethoxysilane, tetramethoxysilane, phenyl triethoxysilane, methyl triethoxysilane, octamethylcyclotetrasiloxane, and the like. In addition, among the above organosilicon compounds, it is preferable to use tetramethoxysilane (TMOS) and hexamethyldisiloxane (HMDSO). These are because they are excellent in handling properties and characteristics of a vapor deposition film.

The thickness of the inorganic layer is, for example, 1 nm to 500 nm, preferably 5 nm to 300 nm, and more preferably 10 nm to 150 nm. This is because, when the thickness of the inorganic layer is within the above-described range, reflection in the inorganic layer can be suppressed while realizing good barrier properties, and a wavelength conversion member having a higher light transmittance can be provided.

In the wavelength conversion member, in one aspect, it is preferable that at least one main surface of the wavelength conversion layer is in direct contact with the inorganic layer. It is also preferable that the inorganic layer is in direct contact with both main surfaces of the wavelength conversion layer. In addition, in one aspect, it is preferable that at least one main surface of the wavelength conversion layer is in direct contact with the organic layer. It is also preferable that the organic layer is in direct contact with both main surfaces of the wavelength conversion layer. Here, the "main surface" refers to the surface (surface, back surface) of the wavelength conversion layer disposed on the visible side or the backlight side when the wavelength conversion member is used. The same applies to the major surfaces of other layers or members. Further, between an inorganic layer and an organic layer, between two inorganic layers, or between two organic layers may be bonded together by a known adhesive layer. From the viewpoint of improving the light transmittance, the smaller the adhesive layer is, the more preferable it is, and it is more preferable that no adhesive layer is present. In one aspect, it is preferable that the inorganic layer and the organic layer are in direct contact.

-Organic layer-

As the organic layer, Japanese Patent Application Laid-Open No. 2007-290369, paragraphs 0020 to 0402, and Japanese Patent Application No. 2005-096108, paragraphs 0074 to 0105, can be referred to. Moreover, it is preferable that an organic layer contains a cardo polymer in one aspect. This is because the adhesion of the layer adjacent to the organic layer, particularly the adhesion to the inorganic layer is improved, and further superior gas barrier properties can be realized. For details of the cardo polymer, reference can be made to Japanese Unexamined Patent Application Publication No. 2005-096108, paragraphs 0085 to 0095. The thickness of the organic layer is preferably in the range of 0.05 µm to 10 µm, and particularly preferably in the range of 0.5 to 10 µm. When the organic layer is formed by the wet coating method, the thickness of the organic layer is preferably in the range of 0.5 to 10 µm, especially in the range of 1 µm to 5 µm. Further, in the case of forming by a dry coating method, it is preferably in the range of 0.05 µm to 5 µm, and especially in the range of 0.05 µm to 1 µm. This is because the adhesion with the inorganic layer can be made more favorable when the thickness of the organic layer formed by the wet coating method or the dry coating method is within the above-described range.

In addition, in the present invention and this specification, a polymer refers to a polymer in which two or more compounds of the same or different are polymerized by a polymerization reaction, and is used in a sense including an oligomer, and its molecular weight is not particularly limited. In addition, the polymer may be a polymer having a polymerizable group, which can be further polymerized by performing a polymerization treatment according to the type of the polymerizable group such as heating or light irradiation. Moreover, polymerizable compounds, such as an epoxy compound, a monofunctional (meth)acrylate compound, and a polyfunctional (meth)acrylate compound mentioned above, may correspond to a polymer in the above meaning.

Further, the organic layer may be a cured layer formed by curing a polymerizable composition containing a (meth)acrylate polymer. The (meth)acrylate polymer is a polymer containing one or more (meth)acryloyl groups per molecule. As an example of the (meth)acrylate polymer used for forming the organic layer, a (meth)acrylate polymer containing one or more urethane bonds per molecule may be mentioned. Hereinafter, a (meth)acrylate polymer containing at least one urethane bond per molecule is described as a (meth)acrylate polymer containing a urethane bond. When the barrier layer includes two or more organic layers, a cured layer formed by curing a polymerizable composition containing a urethane bond-containing (meth)acrylate polymer and another organic layer may be included. In one aspect, it is preferable that the organic layer in direct contact with one or both of the main surfaces of the wavelength conversion layer is a cured layer formed by curing a polymerizable composition containing a urethane bond-containing (meth)acrylate polymer.

In the urethane bond-containing (meth)acrylate polymer, in one embodiment, it is preferable that the structural unit having a urethane bond is introduced into the side chain of the polymer. In the following, the main chain into which the structural unit having a urethane bond is introduced is described as an acrylic main chain.

Moreover, it is also preferable that a (meth)acryloyl group is contained in at least one terminal of the side chain which has a urethane bond. It is more preferable that a (meth)acryloyl group is contained in all of the side chains having a urethane bond. Here, it is more preferable that the (meth)acryloyl group contained in the terminal is an acryloyl group.

The urethane bond-containing (meth)acrylate polymer can generally be obtained by graft copolymerization, but is not particularly limited. The structural unit having an acrylic main chain and a urethane bond may be directly bonded or may be bonded via a linking group. Examples of the linking group include an ethylene oxide group, a polyethylene oxide group, a propylene oxide group, and a polypropylene oxide group. The urethane bond-containing (meth)acrylate polymer may contain a plurality of side chains in which structural units having a urethane bond are bonded via different linking groups (including direct bonds).

The urethane bond-containing (meth)acrylate polymer may have side chains other than the structural unit having a urethane bond. As an example of another side chain, a linear or branched alkyl group is mentioned. As a linear or branched alkyl group, a C1-C6 linear alkyl group is preferable, an n-propyl group, an ethyl group, or a methyl group is more preferable, and a methyl group is more preferable. In addition, other side chains may contain those of different structures. This point is also the same for the structural unit having a urethane bond.

The number of urethane bonds and (meth)acryloyl groups contained in one molecule of the urethane bond-containing (meth)acrylate polymer is 1 or more, preferably 2 or more, but is not particularly limited. The weight average molecular weight of the urethane bond-containing (meth)acrylate polymer is preferably 10,000 or more, more preferably 12,000 or more, and still more preferably 15,000 or more. In addition, the weight average molecular weight of the urethane bond-containing (meth)acrylate polymer is preferably 1,000,000 or less, more preferably 500,000 or less, and still more preferably 300,000 or less. The acrylic equivalent of the urethane bond-containing (meth)acrylate polymer is preferably 500 or more, more preferably 600 or more, more preferably 700 or more, and more preferably 5,000 or less, and more preferably 3,000 or less. And more preferably 2,000 or less. The acrylic equivalent is a value obtained by dividing the weight average molecular weight by the number of (meth)acryloyl groups in one molecule.

As the urethane bond-containing (meth)acrylate polymer, one synthesized by a known method may be used, or a commercial product may be used. As a commercial item, the Daisei Fine Chemical Co., Ltd. UV curable acrylic urethane polymer (8BR series) is mentioned, for example. The urethane bond-containing (meth)acrylate polymer is preferably contained in an amount of 5 to 90% by mass, and more preferably 10 to 80% by mass based on 100% by mass of the total solid content of the polymerizable composition for forming an organic layer.

In the curable compound used to form the organic layer, one or more types of urethane bond-containing (meth)acrylate polymers and one or more types of other polymerizable compounds may be used in combination. As another polymerizable compound, a compound having an ethylenically unsaturated bond in the terminal or side chain is preferable. Examples of the compound having an ethylenically unsaturated bond in the terminal or side chain include a (meth)acrylate compound, an acrylamide compound, a styrene compound, and maleic anhydride, and a (meth)acrylate compound is preferable. Rate compounds are more preferred.

As the (meth)acrylate compound, (meth)acrylate, polyester (meth)acrylate, epoxy (meth)acrylate, and the like are preferable. Specific examples of the (meth)acrylate compound include compounds described in paragraphs 0024 to 0036 of JP2013-43382A or paragraphs 0036 to 0048 of JP2013-43384A.

As the styrene-based compound, styrene, α-methylstyrene, 4-methylstyrene, divinylbenzene, 4-hydroxystyrene, 4-carboxystyrene, and the like are preferable.

The polymerizable composition used to form the organic layer may contain a known additive together with one or more polymerizable compounds. As an example of such an additive, an organometallic coupling agent is mentioned. For details, reference can be made to the above description. When the total solid content of the polymerizable composition used for forming the organic layer is 100% by mass, the organometallic coupling agent is preferably 0.1 to 30% by mass, and more preferably 1 to 20% by mass.

Moreover, as an additive, a polymerization initiator is mentioned. When a polymerization initiator is used, the content of the polymerization initiator in the polymerizable composition is preferably 0.1 mol% or more, and more preferably 0.5 to 5 mol% of the total amount of the polymerizable compound. Examples of photopolymerization initiators are the Irgacure series sold by BASF (e.g., Irgacure 651, Irgacure 754, Irgacure 184, Irgacure 2959, Irgacure 907, Irgacure) 369, Irgacure 379, Irgacure 819, etc.), Darocure series (e.g., Darocure TPO, Darocure 1173, etc.), Quantacure PDO, Lamberti A commercially available Ezacure series (eg, Ezacure TZM, Ezacure TZT, Ezacure KTO46, etc.) may be mentioned.

The curing of the polymerizable composition for forming the organic layer may be performed by treatment (light irradiation, heating, etc.) depending on the type of the component (polymerizable compound or polymerization initiator) contained in the polymerizable composition. The curing conditions are not particularly limited, and may be set according to the kind of components contained in the polymerizable composition, the thickness of the organic layer, and the like.

For other details of the inorganic layer and the organic layer, reference may be made to the description of Japanese Unexamined Patent Publication No. 2007-290369, Japanese Unexamined Patent Publication No. 2005-096108, and US2012/0113672A1.

Between an organic layer and an inorganic layer, between two organic layers, or between two inorganic layers, you may bond with a well-known adhesive layer. From the viewpoint of improving the light transmittance, the smaller the adhesive layer is, the more preferable it is, and it is more preferable that no adhesive layer is present.

[Backlight unit]

A backlight unit according to an aspect of the present invention includes at least the wavelength conversion member and a light source described above. The details of the wavelength conversion member are as described above.

(Light emission wavelength of backlight unit)

From the viewpoint of realization of high luminance and high color reproducibility, it is preferable to use a multi-wavelength light source as the backlight unit. As a preferred aspect,

Blue light having an emission center wavelength in a wavelength band of 430 to 480 nm and a peak of emission intensity having a half width of 100 nm or less; and

Green light having an emission center wavelength in a wavelength band of 500 to 600 nm and a peak of emission intensity having a half width of 100 nm or less; and

Red light having an emission center wavelength in a wavelength range of 600 to 680 nm and a peak of emission intensity with a half width of 100 nm or less

And a backlight unit that emits light.

From the viewpoint of higher luminance and improvement of color reproducibility, the wavelength band of blue light emitted by the backlight unit is preferably in the range of 440 to 480 nm, and more preferably in the range of 440 to 460 nm.

From the same point of view, the wavelength band of green light emitted by the backlight unit is preferably in the range of 510 to 560 nm, and more preferably in the range of 510 to 545 nm.

Further, from the same viewpoint, the wavelength band of the red light emitted by the backlight unit is preferably in the range of 600 to 650 nm, and more preferably in the range of 610 to 640 nm.

Further, from the same point of view, the half width of each light emission intensity of blue light, green light, and red light emitted by the backlight unit is preferably 80 nm or less, more preferably 50 nm or less, further preferably 40 nm or less, and 30 nm. It is more preferable that it is the following. Among these, it is particularly preferable that the half-value width of each emission intensity of blue light is 25 nm or less.

The backlight unit includes at least a light source together with the wavelength conversion member. In one embodiment, as a light source, one emitting blue light having a light emission center wavelength in a wavelength band of 430 nm to 480 nm, for example, a blue light emitting diode emitting blue light can be used. When a light source emitting blue light is used, it is preferable that the wavelength conversion layer includes at least quantum dots A that are excited by excitation light to emit red light, and quantum dots B that emit green light. Accordingly, white light may be realized by blue light emitted from the light source and transmitted through the wavelength conversion member, and red light and green light emitted from the wavelength conversion member.

Alternatively, in another embodiment, as a light source, an ultraviolet light emitting diode having an emission center wavelength in a wavelength band of 300 nm to 430 nm can be used, for example, an ultraviolet light emitting diode. In this case, it is preferable that the wavelength conversion layer contains quantum dots C that are excited by excitation light to emit blue light, together with quantum dots A and B. Accordingly, white light may be realized by red light, green light, and blue light emitted from the wavelength conversion member.

Further, in another aspect, the light emitting diode can be substituted as a laser light source.

(Configuration of backlight unit)

The configuration of the backlight unit may be an edge light system in which a light guide plate, a reflective plate, or the like is used as a constituent member, or a direct type system. In Fig. 1, as an embodiment, an example of an edge light type backlight unit is shown. As the light guide plate, a known one can be used without any limitation.

Further, the backlight unit may include a reflective member at the rear of the light source. The reflective member is not particularly limited, and known ones can be used, and are described in Japanese Patent No. 3416302, Japanese Patent 3363565, Japanese Patent 4091978, Japanese Patent 3448626, and the like, and the contents of these publications are It is introduced in the present invention.

In addition, the backlight unit preferably includes a well-known diffusion plate or diffusion sheet, a prism sheet (eg, BEF series manufactured by Sumitomo 3M, etc.), and a light guide. Other members are also described in Japanese Patent No. 3416302, Japanese Patent No. 3363565, Japanese Patent No. 4091978, and Japanese Patent No. 3448626, and the contents of these publications are described in the present invention. Is introduced in

[Liquid crystal display device]

A liquid crystal display device according to an aspect of the present invention includes at least the above-described backlight unit and a liquid crystal cell.

(Configuration of liquid crystal display device)

There is no particular limitation on the driving mode of the liquid crystal cell, and twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA), in-plane switching (IPS), optically compensated bend cell (OCB) Various modes such as can be used. The liquid crystal cell is preferably in a VA mode, an OCB mode, an IPS mode, or a TN mode, but is not limited thereto. As an example of the configuration of a liquid crystal display device in VA mode, the configuration shown in Fig. 2 of Japanese Unexamined Patent Application Publication No. 2008-262161 is exemplified. However, there is no particular limitation on the specific configuration of the liquid crystal display device, and a known configuration can be adopted.

In one embodiment of the liquid crystal display device, a liquid crystal cell is provided in which a liquid crystal layer is sandwiched between substrates provided with electrodes on at least one of the opposite sides, and the liquid crystal cell is configured by being disposed between two polarizing plates. A liquid crystal display device includes a liquid crystal cell in which a liquid crystal is sealed between upper and lower substrates, and displays an image by changing the alignment state of the liquid crystal by applying a voltage. In addition, it has a polarizing plate protective film, an optical compensation member for performing optical compensation, an adhesive layer, and the like accompanying a functional layer as necessary. In addition, with (or instead of) a color filter substrate, a thin layer transistor substrate, a lens film, a diffusion sheet, a hard coating layer, an antireflection layer, a low reflection layer, an anti-glare layer, etc., a front scattering layer, a primer layer, an antistatic layer, an undercoat layer, etc. The surface layer of may be disposed.

2 shows an example of a liquid crystal display device according to an aspect of the present invention. The liquid crystal display device 51 shown in FIG. 2 has a backlight-side polarizing plate 14 on the surface of the liquid crystal cell 21 on the backlight side. The backlight-side polarizing plate 14 may or may not contain the polarizing plate protective film 11 on the surface of the backlight-side polarizer 12, but is preferably included.

It is preferable that the backlight-side polarizing plate 14 has a configuration in which the polarizer 12 is sandwiched between two polarizing plate protective films 11 and 13.

In this specification, the polarizing plate protective film on the side close to the liquid crystal cell with respect to the polarizer is referred to as the inner polarizing plate protective film, and the polarizing plate protective film on the side far from the liquid crystal cell with respect to the polarizer is referred to as the outer polarizing plate protective film. In the example shown in FIG. 2, the polarizing plate protective film 13 is an inner-side polarizing plate protective film, and the polarizing plate protective film 11 is an outer-side polarizing plate protective film.

The backlight-side polarizing plate may have a retardation film as an inner-side polarizing plate protective film on the liquid crystal cell side. As such a retardation film, a known cellulose acylate film or the like can be used.

The liquid crystal display device 51 has a display-side polarizing plate 44 on a surface of the liquid crystal cell 21 on the side opposite to the surface on the backlight side. The display-side polarizing plate 44 has a configuration in which the polarizer 42 is sandwiched between two polarizing plate protective films 41 and 43. The polarizing plate protective film 43 is an inner-side polarizing plate protective film, and the polarizing plate protective film 41 is an outer-side polarizing plate protective film.

The backlight unit 1 included in the liquid crystal display device 51 is as described above.

There is no particular limitation on a liquid crystal cell, a polarizing plate, a polarizing plate protective film, and the like constituting the liquid crystal display according to an aspect of the present invention, and a product manufactured by a known method or a commercial product may be used without any limitation. In addition, it is of course possible to provide a known intermediate layer such as an adhesive layer between the respective layers.

Since the liquid crystal display device according to an aspect of the present invention described above includes a backlight unit including the wavelength conversion member, high luminance and high color reproducibility can be realized over a long period of time.

[Example]

Hereinafter, the present invention will be described in more detail based on examples. Materials, amounts used, ratios, treatment contents, treatment procedures, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention should not be limitedly interpreted by the specific examples shown below.

(Example 1)

1. Fabrication of the barrier film 10

An organic layer and an inorganic layer were sequentially formed on one side of a polyethylene terephthalate film (PET film, manufactured by Toyobo, trade name: Cosmo Shine (registered trademark) A4300, thickness 50 µm) in the following order.

Trimethylolpropane triacrylate (TMPTA manufactured by Daicel Cytech, Ltd.) and a photoinitiator (manufactured by Lanberuti, ESACURE KTO46) were prepared and weighed so that the former: the latter = 95:5 as a mass ratio, and these were methyl ethyl ketone. It dissolved in, and it was set as the coating liquid of 15 mass% of solid content concentration. This coating liquid was applied on the PET film by roll-to-roll using a die coater, and passed through a drying zone at 50° C. for 3 minutes. Thereafter, ultraviolet rays were irradiated under a nitrogen atmosphere (integrated dose of about 600 mJ/cm 2 ), cured by ultraviolet curing, and wound up. The thickness of the first organic layer formed on the support film was 1 µm.

Next, an inorganic layer (silicon nitride layer) was formed on the surface of the first organic layer using a roll-to-roll CVD (Chemical Vapor Deposition) device. As the raw material gas, silane gas (flow rate 160 sccm), ammonia gas (flow rate 370 sccm), hydrogen gas (flow rate 590 sccm), and nitrogen gas (flow rate 240 sccm) were used. As the power source, a high-frequency power source with a frequency of 13.56 MHz was used. The film forming pressure was 40 Pa and the resulting thickness was 50 nm. In this way, the barrier film 10 in which the inorganic layer was laminated on the surface of the first organic layer was produced.

2. Preparation of a composition for forming a wavelength conversion layer (a quantum dot-containing polymerizable composition)

As a quantum dot-containing polymerizable composition, the following quantum dot dispersion A was prepared, filtered through a filter made of polypropylene having a pore diameter of 0.2 µm, dried under reduced pressure for 30 minutes, and used as a coating liquid. The quantum dot concentration in the following toluene dispersion was 1% by mass.

Oxygen Permeation Coefficient Reduction 1

3. Fabrication of wavelength conversion member A

The barrier film 10 produced in the above-described procedure was used as the first and second films, and the wavelength conversion member A was obtained by the manufacturing process described with reference to FIGS. 3 and 4. Specifically, a barrier film 10 was prepared as a first film, and, while continuously conveying at a tension of 1 m/min and 60 N/m, a quantum dot-containing polymerizable composition was applied on the surface of the inorganic layer with a die coater, and 50 μm A coating film having a thickness of was formed. Next, the barrier film 10 on which the coating film was formed is wound on a backup roller, and another barrier film 10 as a second film on the coating film is laminated in a direction in which the inorganic layer surface contacts the coating film, and thereafter, two barrier films ( 10) In the state where the coating film was pinched with (1st, 2nd film), it wound up on a backup roller, and it irradiated with ultraviolet rays while conveying continuously. The diameter of the backup roller was 300 mm, and the temperature of the backup roller was 50°C. The irradiation amount of ultraviolet rays was 2000 mJ/cm 2. In addition, L1 was 50 mm, L2 was 1 mm, and L3 was 50 mm.

The coating film was cured by irradiation of the above ultraviolet rays to form a cured layer (wavelength converting layer), and a wavelength converting member A was manufactured. The thickness of the cured layer of the wavelength conversion member was about 50 µm. In this way, a wavelength conversion member A having the barrier films 10 on both surfaces of the wavelength conversion layer, and in which both main surfaces of the wavelength conversion layer are in direct contact with the inorganic layer of the barrier film, was obtained.

(Example 2)

A wavelength conversion member B was produced in the same manner as the oxygen transmission coefficient reduction first of the quantum dot dispersion A of Example 1 was changed to the following oxygen transmission coefficient reduction second.

Oxygen permeation coefficient reduction 2

(Example 3)

A wavelength conversion member C was produced in the same manner as the oxygen transmission coefficient reduction first of the quantum dot dispersion A of Example 1 was changed to the following oxygen transmission coefficient reduction third.

Oxygen Permeation Coefficient Reduction 3

(Example 4)

The wavelength conversion member D was produced in the same manner as the oxygen transmission coefficient reduction first of the quantum dot dispersion A of Example 1 was changed to the following oxygen transmission coefficient reduction fourth.

Oxygen Permeation Coefficient Reduction 4

(Example 5)

A wavelength conversion member E was produced in the same manner as the oxygen transmission coefficient reduction agent 1 of the quantum dot dispersion liquid A of Example 1 was changed to the oxygen transmission coefficient reduction agent 5 below.

Oxygen permeation coefficient reducing agent 5

(Example 6)

1. Preparation of the barrier film 11

A second organic layer was laminated on the surface of the inorganic layer of the barrier film 10. A urethane bond-containing acrylic polymer (Akuritto 8BR500 manufactured by Daisei Fine Chemicals, a weight average molecular weight of 250,000) and a photoinitiator (Irgacure 184 manufactured by BASF) were weighed in a mass ratio of 95:5, and these were dissolved in methyl ethyl ketone. , A coating liquid having a solid content concentration of 15% by mass was prepared. The prepared coating liquid was applied to the surface of the inorganic layer of the barrier film 10 by roll-to-roll using a die coater, passed through a dry zone at 100°C for 3 minutes, and wound up. The thickness of the second organic layer thus formed was 1 µm. In this way, the barrier film 11 in which the inorganic layer was laminated on the surface of the first organic layer and the second organic layer was laminated was produced.

2. Fabrication of wavelength conversion member F

The barrier film 11 produced in the above-described procedure was used as the first and second films, and a wavelength conversion member F was obtained by the manufacturing process described with reference to FIGS. 3 and 4. Specifically, a barrier film 11 was prepared as a first film, and, while continuously conveying at a tension of 1 m/min and 60 N/m, the quantum dot-containing polymerizable composition as in Example 1 (quantum The dot dispersion liquid A) was applied with a die coater to form a coating film having a thickness of 50 µm. Subsequently, the barrier film 11 on which the coating film was formed is wound on a backup roller, and another barrier film 11 as a second film on the coating film is laminated in a direction in which the second organic layer surface is in contact with the coating film, and thereafter, two barriers The film 11 (1st, 2nd film) was wound around a backup roller in the state which pinched the coating film, and it irradiated with ultraviolet rays while conveying continuously. The diameter of the backup roller was 300 mm, and the temperature of the backup roller was 50°C. The irradiation amount of ultraviolet rays was 2000 mJ/cm 2. In addition, L1 was 50 mm, L2 was 1 mm, and L3 was 50 mm.

The coating film was cured by irradiation of the above ultraviolet rays to form a cured layer (wavelength converting layer), and a wavelength converting member F was manufactured. The thickness of the cured layer of the wavelength conversion member was about 50 µm. In this way, a wavelength conversion member F was obtained having the barrier films 11 on both surfaces of the wavelength conversion layer, respectively, and in which both main surfaces of the wavelength conversion layer are in direct contact with the second organic layer of the barrier film.

(Example 7)

In Example 6, except for changing the quantum dot dispersion liquid A to the following quantum dot dispersion liquid G, it carried out similarly, and produced the wavelength conversion member G.

(Example 8)

In Example 6, except for changing the quantum dot dispersion liquid A to the following quantum dot dispersion liquid H, it carried out similarly, and produced the wavelength conversion member H. The toluene dispersions of the following quantum dots 1 and 2 are the same as those used in quantum dot dispersion A.

(Example 9)

In Example 1, except for changing the quantum dot dispersion liquid A to the following quantum dot dispersion liquid J, it carried out similarly, and produced the wavelength conversion member J. The toluene dispersions of the following quantum dots 1 and 2 are the same as those used in quantum dot dispersion A.

(Example 10)

In Example 1, except for changing the quantum dot dispersion liquid A to the following quantum dot dispersion liquid L, it carried out similarly, and produced the wavelength conversion member L. The toluene dispersions of the following quantum dots 1 and 2 are the same as those used in the quantum dot dispersion A.

(Comparative Example 1)

In Example 1, except that the oxygen transmission coefficient reducing first was not used, a wavelength conversion member I was produced in the same manner.

(Comparative Example 2)

In Example 7, except that the oxygen transmission coefficient reducing first was not used, a wavelength conversion member K was produced in the same manner.

(Comparative Example 3)

In Example 8, except that the oxygen transmission coefficient reducing first was not used, a wavelength conversion member M was produced in the same manner.

(Comparative Example 4)

In Example 9, except that the oxygen transmission coefficient reducing first was not used, the wavelength conversion member N was produced in the same manner.

(Comparative Example 5)

In Example 10, the wavelength conversion member O was produced in the same manner except that the oxygen transmission coefficient reducing agent 1 was not used.

<Evaluation of change in luminance at the end>

1. Evaluation of initial (before continuous irradiation) luminance

A commercially available tablet terminal (Amazon's Kindle (registered trademark) Fire HDX 7") was disassembled, and the backlight unit was taken out. The wavelength conversion members A to O cut out into rectangles were placed on the light guide plate of the taken out backlight unit, and on it, Two prism sheets with orthogonal directions were superimposed, and the luminance of the light emitted from the blue light source and transmitted through the wavelength conversion member and the two prism sheets was provided at a position of 740 mm in the vertical direction with respect to the surface of the light guide plate. Measurement was carried out with a meter (SR3, manufactured by TOPCON) In addition, for the measurement, a position (end) of 5 mm inside from the side edge of the wavelength conversion member was measured, and the average value (Y0) of the measurements at the four corners was used as the evaluation value. did.

2. Evaluation of luminance before and after continuous irradiation

In a room maintained at 25°C and 60% relative humidity, each wavelength conversion member was placed on a commercially available blue light source (OPTEX-FA Co., Ltd. OPSM-H150X142B), and blue light was continuously irradiated to the wavelength conversion member for 100 hours. .

The luminance (Y1) of the four corners of the wavelength conversion member after continuous irradiation was measured in the same manner as in the evaluation of the luminance before the continuous irradiation in 1. above, and the rate of change (ΔY) with the initial luminance value of the following formula It was taken as an index of luminance change.

ΔY[%]=(Y0-Y1)/Y0×100

Based on the obtained value of ΔY, the change in luminance at the end was evaluated according to the following criteria. If the evaluation results are A and B, it can be determined that the luminous efficiency at the end is maintained satisfactorily even after continuous irradiation.

(Evaluation standard)

AA ΔY≤10%

A 10%<ΔY≤20%

B 20%<ΔY<40%

C 40%≤ΔY<60%

D 60%≤ΔY

<Evaluation of the oxygen transmission coefficient of the wavelength conversion layer>

The oxygen transmission coefficient converted to the thickness of 1 mm of the wavelength conversion layer produced in Examples and Comparative Examples was evaluated by the following method.

A sample for measuring an oxygen permeation coefficient was produced in the following procedure.

The quantum dot dispersion liquid used in Examples and Comparative Examples prepared in the above procedure was applied to a support film (TD80UL manufactured by Fujifilm) with a wire bar, and a 1200W/cm air-cooled metal halide lamp (manufactured by Eye Graphics) was used while purging with nitrogen. Was irradiated from the coated surface and cured to form a film with a wavelength conversion layer having a thickness of 50 μm. Next, the oxygen transmission coefficient of the film with the wavelength conversion layer is affixed to the detection unit of the Hach Ultra type oxygen concentration meter via silicone grease, and the oxygen transmission coefficient (P0) from the equilibrium oxygen concentration value Converted to. Similarly, the oxygen transmission coefficient (P1) of only the support film was measured, and the oxygen transmission coefficient (P) per 1 mm of the thickness of each wavelength conversion layer was calculated from the following equation. The calculated values are shown in the following table. The value calculated in this way is shown in the following table as the oxygen transmission coefficient per 1 mm of the thickness of the wavelength conversion layer included in each wavelength conversion member.

P=T/((T0/P0)-(T1/P1))

[In the above formula, T is the thickness of the wavelength conversion layer, T0 is the thickness of the film with the wavelength conversion layer, and T1 is the thickness of the support film. The unit of thickness is "mm"]

<Evaluation of the oxygen permeation coefficient reducing ability of the oxygen permeation coefficient reducing agent>

The oxygen transmission coefficient reduction rate of the oxygen transmission coefficient reducing agent used in each example with respect to the wavelength conversion layer included in each wavelength conversion member was determined by the oxygen transmission coefficient of each example and the quantum dot dispersion formulation excluding the oxygen transmission coefficient reducing agent. From the oxygen permeation coefficient of such a comparative example, it can be calculated by the equation described above. Specifically, it calculated|required with the values shown in the following table about Examples 1-6 and the values shown in the following table about comparative example 1. Similarly, Comparative Example 2 for Example 7, Comparative Example 3 for Example 8, Comparative Example 4 for Example 9, and Comparative Example 5 for Example 10, and the oxygen permeation coefficient reduction rate was calculated. The results are shown in the table below.

[Table 1]

As shown in the table above, it was confirmed that the wavelength converting member of the example exhibits a good luminous efficiency even after continuous ultraviolet irradiation, since the luminance change at the end is less than that of the wavelength converting member of the comparative example. From this, it can be confirmed that in the wavelength conversion member of the example, the decrease in luminance at the end portion due to intrusion of oxygen from the side surface of the wavelength conversion layer that is not protected by the barrier film is suppressed.

The present invention is useful in the field of manufacturing a liquid crystal display device.

Claims (12)

It is a backlight unit including at least a wavelength conversion member and a light source,
The wavelength conversion member is a rectangular wavelength conversion member having a wavelength conversion layer including quantum dots that are excited by excitation light to emit fluorescence,
The wavelength conversion layer includes the quantum dot and an oxygen transmission coefficient reducing agent,
The oxygen transmission coefficient converted per 1 mm of the thickness of the wavelength conversion layer is less than 150.0 cm 3 /m 2 /day/atm, and
The oxygen transmission coefficient reducing agent is, in the wavelength conversion layer, per 10 parts by mass of the content of the oxygen transmission coefficient reducing agent to 100 parts by mass of the wavelength conversion layer excluding the oxygen transmission coefficient reducing agent, of the wavelength conversion layer. As a compound showing an oxygen permeation coefficient reduction ability that reduces the oxygen permeation coefficient converted to per 1 mm of thickness by 30% or more, a biphenyl compound, a hydrogenated biphenyl compound, a terphenyl compound, a bisphenol compound, a hydrogenated bisphenol compound, a trityl compound, It is at least one compound selected from the group consisting of a trityl hydride compound, a cardo compound, and a benzophenone compound,
A backlight unit having a rate of change ΔY of less than 40% of the luminance Y1 after 100 hours of continuous irradiation of blue light from the light source to the wavelength conversion member from the light source under an environment of a temperature of 25°C and a relative humidity of 60% by the following equation ;
ΔY[%]=(Y0-Y1)/Y0×100
In the above formula, Y0 is the average value of the luminance measured before the irradiation at a position corresponding to 4 places 5 mm inside from the edge of the side surface of the wavelength conversion member, and Y1 is the average value of the luminance measured after the irradiation at the position. Is,
The light source is a light source that emits blue light having an emission center wavelength in a wavelength range of 430 to 480 nm The method of claim 1,
The wavelength conversion layer is a backlight unit containing 1 to 50 parts by mass of the oxygen transmission coefficient reducing agent. delete The method according to claim 1 or 2,
The oxygen transmission coefficient reducing agent is a backlight unit of a compound having a molecular weight of 2000 or less. The method according to claim 1 or 2,
The wavelength conversion layer, the quantum dot and oxygen transmission coefficient reducing agent, and at least one polymerizable selected from the group consisting of a monofunctional (meth) acrylate compound, a polyfunctional (meth) acrylate compound, and an epoxy compound A backlight unit which is a cured layer formed by curing a polymerizable composition containing a compound. The method according to claim 1 or 2,
The thickness of the wavelength conversion layer is in the range of 1 to 500㎛ backlight unit. The method according to claim 1 or 2,
The quantum dot,
Quantum dot A having an emission center wavelength in a wavelength band in the range of 600 nm to 680 nm,
Quantum dot B having an emission center wavelength in a wavelength band ranging from 500 nm to 600 nm, and
A backlight unit of at least one type selected from the group consisting of quantum dots C having an emission center wavelength in a wavelength range of 400 nm to 500 nm. The method according to claim 1 or 2,
The wavelength conversion member has at least one layer selected from the group consisting of an inorganic layer and an organic layer on at least one main surface of the wavelength conversion layer. The method of claim 8,
The wavelength conversion member has at least one layer selected from the group consisting of an inorganic layer and an organic layer, respectively, on one major surface of the wavelength conversion layer and the other major surface of the wavelength conversion layer. The backlight unit according to claim 1 or 2, and
Liquid crystal cell
A liquid crystal display device comprising at least. delete delete

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