JP6653622B2 - Wavelength conversion member, backlight unit, liquid crystal display, and quantum dot-containing polymerizable composition - Google Patents

Description

  The present invention relates to a wavelength conversion member. Further, the present invention relates to a backlight unit including the wavelength conversion member and a liquid crystal display device including the backlight unit. The present invention further relates to a polymerizable composition containing quantum dots that can be used for producing a wavelength conversion member.

  2. Description of the Related Art Flat panel displays such as liquid crystal display devices (hereinafter also referred to as LCDs (Liquid Crystal Displays)) have low power consumption and are increasingly used as space-saving image display devices year by year. The liquid crystal display device includes 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, color reproducibility is improving as LCD performance is improving. In this regard, in recent years, quantum dots (also called Quantum Dots, QDs, and quantum dots) have attracted attention as a light emitting material (see Patent Document 1). For example, when excitation light is incident on a wavelength conversion member including quantum dots from a backlight, the quantum dots are excited and emit fluorescence. Here, by using quantum dots having different emission characteristics, white light can be realized by emitting red light, green light, and blue light. Since the fluorescence by the quantum dots has a small half-value width, 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 gamut has been expanded from 72% to 100% of NTSC (National Television System Committee).

JP-T-2013-544018A International Publication No. 2011/031876 International Publication No. WO 2013/078252

  The wavelength conversion member including quantum dots has a problem that when excitation light is incident upon turning on the display, the quantum dots are exposed to a high temperature, and the emission intensity decreases with time. This problem is considered to be derived from the low light durability of the quantum dots, specifically, the reduction of the light emission intensity due to oxidation reaction or the like when oxygen or water comes into contact with the quantum dots. In this regard, Patent Document 1 proposes laminating a barrier film on a layer containing quantum dots in order to protect the quantum dots from oxygen and the like.

  Regarding the light resistance improvement of the wavelength conversion member containing quantum dots, Patent Document 2 discloses a HALS stabilizer (a hindered amine-based light stabilizer) and a UVA stabilizer (an ultraviolet absorber). A luminescence stabilizer containing a specific phosphorus compound or the like is disclosed. These measures have shown certain effectiveness with respect to stability when irradiated with excitation light. However, the technique described in Patent Document 2 has a deteriorating effect such as curing inhibition when forming a wavelength conversion member by forming a matrix from a composition containing a photocurable monomer and quantum dots.

On the other hand, the wavelength conversion member containing the quantum dots is not only stable at the time of irradiation with the excitation light, but also has the stability of the light emission intensity under storage without light irradiation after forming the wavelength conversion member, and the wavelength conversion. It was found that there was a problem that the initial light emission intensity fluctuated depending on the conditions at the time of manufacturing the member, and a new technique was required.
The present inventors have extensively studied organophosphorus compounds, and as a result, it has a structure different from that of organophosphorus phosphonic acids, phosphinic acids, phosphine oxides, and phosphines used as ligands for quantum dots and synthetic solvents. It has been found that a specific phosphite triester-based compound is effective in improving the thermal durability of the quantum dot-containing wavelength conversion member and stabilizing the emission intensity when manufacturing conditions are changed.

  The present invention has been made in view of the above circumstances, and provides, as a wavelength conversion member including quantum dots, a wavelength conversion member that has a small variation in light emission intensity during manufacture and has a low light emission intensity after storage at a high temperature. The purpose is to do. Another object of the present invention is to provide a composition having a small variation in luminous intensity and capable of producing a wavelength conversion member including a quantum dot whose luminous intensity hardly decreases after storage at a high temperature. And Another object of the present invention is to provide a highly durable backlight unit and a liquid crystal display device.

  In order to solve the above problems, the present inventors, by adding to the composition containing the quantum dots, stabilizes the initial lot-to-lot variation of the emission intensity, and suppresses the decrease in emission intensity after storage at high temperature. As a result of intensive studies on additives, the present invention has been completed.

  That is, the wavelength conversion member of the present invention is a wavelength conversion member having a wavelength conversion layer including a quantum dot that emits fluorescence when excited by excitation light, wherein the wavelength conversion layer includes an organic matrix, and the organic matrix includes a polymer and Contains phosphoric acid triesters.

  The phosphite triester is preferably a phosphite triester compound having two ester portions linked to each other and having a cyclic structure.

  Further, the phosphite triester is preferably a phosphite triester compound in which at least one of the ester portions contains an aromatic group having a tertiary alkyl group.

  The phosphite triester is preferably a phosphite triester compound having a softening point or a melting point of 40 ° C. or more and 300 ° C. or less.

  The polymer is preferably a polymer of a (meth) acrylate monomer.

  The polymer is preferably a polymer of a monofunctional (meth) acrylate monomer and a polyfunctional (meth) acrylate monomer.

  Further, it is preferable that the organic matrix of the wavelength conversion layer contains a polymer of a (meth) acrylate monomer, and further contains a compound having a ring-opening polymerizable group or a polymer thereof in the organic matrix. The organic matrix of the wavelength conversion layer contains a polymer of a monofunctional (meth) acrylate monomer and a polyfunctional (meth) acrylate monomer, and further contains a compound having a ring-opening polymerizable group or a polymer thereof in the organic matrix. Is preferred.

  The wavelength conversion layer contains at least one photopolymerization initiator, and the photopolymerization initiator is preferably a monoacylphosphine oxide-based compound.

  Further, the polymer may be a polymer of a compound having an epoxy group.

  Further, it is preferable that the wavelength conversion member of the present invention includes a substrate, and at least one surface of the wavelength conversion layer is in direct contact with the substrate.

  Further, the wavelength conversion member of the present invention includes two base materials, each of which is a barrier film including an inorganic layer, and may include a wavelength conversion layer between the two barrier films.

The oxygen permeability of each of the two barrier films is preferably 1 cm ³ / (m ² · day · atm) or less.

  In the wavelength conversion member of the present invention, the quantum dots may include a first quantum dot having an emission center wavelength of 500 nm to 600 nm and a second quantum dot having an emission center wavelength of 600 to 680 nm.

  The backlight unit of the present invention includes at least the wavelength conversion member of the present invention and a light source.

  In the backlight unit of the present invention, the light source is preferably a blue light emitting diode or an ultraviolet light emitting diode.

  The backlight unit of the present invention may further include a light guide plate, and the wavelength conversion member may be arranged on a path of light emitted from the light guide plate.

  Further, the backlight unit of the present invention may further include a light guide plate, and the wavelength conversion member may be disposed between the light guide plate and the light source.

  The liquid crystal display of the present invention includes at least the backlight unit of the present invention and a liquid crystal cell.

  The quantum dot-containing polymerizable composition of the present invention includes quantum dots that emit fluorescence when excited by excitation light, at least one of a radical polymerizable compound and a ring-opening polymerizable compound, and a phosphite triester. .

  The radical polymerizable compound is preferably a (meth) acrylate monomer.

  Further, the radical polymerizable compound may include a monofunctional (meth) acrylate monomer and a polyfunctional (meth) acrylate monomer.

  The polymerizable composition containing quantum dots of the present invention contains at least one photopolymerization initiator, and the photopolymerization initiator may be a monoacylphosphine oxide-based compound.

  The ring-opening polymerizable compound may be a compound having an epoxy group.

  Further, the quantum dot-containing polymerizable composition of the present invention contains a radical polymerizable compound and a ring-opening polymerizable compound, and the content of the ring-opening polymerizable compound is 0.05% by mass based on all polymerizable compounds. It is preferably at least 10.0 mass%.

  According to the present invention, there is provided, as a wavelength conversion member including a quantum dot, a wavelength conversion member that has a small variation in light emission intensity at the time of manufacture and has a low light emission intensity after being stored at a high temperature. Further, according to the present invention, a quantum dot-containing polymerizable composition which is a composition having a small variation in light emission intensity and which enables production of a wavelength conversion member including a quantum dot whose light emission intensity is hardly reduced after storage at a high temperature. Provided.

FIGS. 1A and 1B are schematic configuration diagrams of an example of a backlight unit including a wavelength conversion member. FIG. 2 is a schematic configuration diagram of an example of a wavelength conversion member manufacturing apparatus. FIG. 3 is a partially enlarged view of the manufacturing apparatus shown in FIG. FIG. 4 is a schematic configuration diagram illustrating an example of a liquid crystal display device.

The following description may be made based on representative embodiments of the present invention, but the present invention is not limited to such embodiments. In this specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit and an upper limit.
In this specification, the “half width” of a peak refers to the width of the peak at a peak height of ２. Further, light having a light emission center wavelength in a wavelength band of 400 to 500 nm, preferably 430 to 480 nm is called blue light, light having a light emission center wavelength in a wavelength band of 500 to 600 nm is called green light, Light having an emission center wavelength in a wavelength band of ６680 nm is referred to as red light.

  In the present specification, the “polymerizable composition” is a composition containing at least one polymerizable compound, and has a property of being cured by being subjected to polymerization treatment such as light irradiation and heating. The “polymerizable compound” is a compound containing one or more polymerizable groups in one molecule. The polymerizable group is a group that can participate in a polymerization reaction. The above details will be described later.

  Further, in this specification, a description regarding an angle such as “perpendicular” includes a range of an error allowed in a technical field to which the present invention belongs. For example, it means that the angle is within a range of a strict angle of ± 10 °, and an error from the strict angle is preferably 5 ° or less, more preferably 3 ° or less.

[Wavelength conversion member]
The wavelength conversion member only has to have a function of converting at least a part of the wavelength of the incident light and emitting light having a wavelength different from the wavelength of the incident light. The shape of the wavelength conversion member is not particularly limited, and may be any shape such as a sheet shape or a bar shape. The wavelength conversion member only needs to include the wavelength conversion layer including the quantum dots. The wavelength conversion layer is a layer containing quantum dots and an organic matrix. The wavelength conversion member can be used, for example, as a constituent member of a backlight unit of a liquid crystal display device.

FIG. 1 is a schematic configuration diagram of an example of a backlight unit 1 including a wavelength conversion member. In FIG. 1, the backlight unit 1 includes a light source 1A and a light guide plate 1B for forming a surface light source. In the example shown in FIG. 1A, the wavelength conversion member is arranged on the path of light emitted from the light guide plate. On the other hand, in the example shown in FIG. 1B, the wavelength conversion member is arranged between the light guide plate and the light source.
Then, in the example shown in FIG. 1A, the light emitted from the light guide plate 1B enters the wavelength conversion member 1C. In the example shown in FIG. 1A, the light 2 emitted from the light source 1A arranged at the edge of the light guide plate 1B is blue light, and the liquid crystal is viewed from the surface of the light guide plate 1B on the liquid crystal cell (not shown) side. The light is emitted toward the cell. The wavelength conversion member 1C disposed on the path of the light (blue light 2) emitted from the light guide plate 1B includes a quantum dot A excited by the blue light 2 to emit red light 4 and a quantum dot A excited by the blue light 2 to emit green light. And a quantum dot B that emits light 3. In this manner, the excited green light 3 and red light 4 and the blue light 2 transmitted through the wavelength conversion member 1C are emitted from the backlight unit 1. By emitting red light, green light and blue light in this way, white light can be realized.
The example shown in FIG. 1B is the same as the embodiment shown in FIG. 1A except that the arrangement of the wavelength conversion member and the light guide plate is different. In the example shown in FIG. 1B, the excited and emitted green light 3 and red light 4 and the blue light 2 transmitted through the wavelength conversion member 1C are emitted from the wavelength conversion member 1C and are incident on the light guide plate, and the surface light source Is realized.

(Wavelength conversion layer)
The wavelength conversion member has at least a wavelength conversion layer containing quantum dots. The wavelength conversion layer includes quantum dots in an organic matrix. In the present specification, the organic matrix means a portion that does not include quantum dots but includes a polymer. The wavelength conversion layer can be formed from a quantum dot-containing polymerizable composition containing a quantum dot, at least one of a radical polymerizable compound and a ring-opening polymerizable compound, and a phosphite triester compound. The wavelength conversion layer may optionally contain one or more components in addition to the components described above. The polymer may be a polymer obtained by polymerization of at least one of a radical polymerizable compound and a ring-opening polymerizable compound described below. The shape of the wavelength conversion layer is not particularly limited, and may be any shape such as a sheet shape or a bar shape.
In this specification, the “main surface” of the wavelength conversion layer refers to the front surface (front surface, back surface) of the wavelength conversion layer disposed on the viewing side or the backlight side when the wavelength conversion member is used.

(Quantum dot-containing polymerizable composition)
The quantum dot-containing polymerizable composition contains a quantum dot and a polymerizable compound. As the polymerizable compound, at least one of a radical polymerizable compound and a ring-opening polymerizable compound is used, and the quantum dot-containing polymerizable composition includes a phosphite triester compound. The quantum dot-containing polymerizable composition may contain other components such as a polymerization initiator and a silane coupling agent.

(Quantum dot)
The quantum dots emit fluorescence when excited by the excitation light. The wavelength conversion layer includes at least one type of quantum dot, and may also include two or more types of quantum dots having different emission characteristics. Known quantum dots include a quantum dot (A) having an emission center wavelength in a wavelength band of 600 nm to 680 nm, a quantum dot (B) having an emission center wavelength in a wavelength band of 500 nm to 600 nm, and 400 nm to 500 nm. There is a quantum dot (C) having a light emission center wavelength in a wavelength band of, the quantum dot (A) is excited by excitation light to emit red light, the quantum dot (B) emits green light, and the quantum dot (C) Emits blue light. For example, when blue light is incident as excitation light on a wavelength conversion layer containing quantum dots (A) and quantum dots (B), as shown in FIG. 1, red light and quantum dots emitted by quantum dots (A) are emitted. White light can be realized by the green light emitted by (B) and the blue light transmitted through the wavelength conversion layer. Alternatively, by emitting ultraviolet light as excitation light to the wavelength conversion layer containing the quantum dots (A), (B), and (C), red light and quantum dots (B) emitted by the quantum dots (A) are emitted. White light can be embodied by the green light emitted by the device and the blue light emitted by the quantum dot (C). As the quantum dots, those prepared by a known method and commercial products can be used without any limitation. Regarding quantum dots, for example, JP-A-2012-169271, paragraphs 0060 to 0066 can be referred to, but the quantum dots are not limited to those described here. The emission wavelength of a quantum dot can usually be adjusted by the composition and size of the particles, and the composition and size. It is preferable that the quantum dot includes at least one of a group II compound semiconductor, a group III compound semiconductor, a group V compound semiconductor, and a group VI compound semiconductor. More specifically, the core nanocrystal is preferably Cdse, InGaP, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe, or HgS. The shell nanocrystal is preferably made of CuZnS, CdSe, CdTe, ZnSe, ZnTe, ZnS, HgTe, or HgS.

  It is preferable that the light conversion layer in the light conversion member according to one embodiment of the present invention emits fluorescent light having at least a part of polarization of incident light, from the viewpoints of luminance improvement and low power consumption. As a specific example of a light conversion layer capable of emitting fluorescence while maintaining at least a part of polarization of incident light, a quantum rod type quantum described in Non-Patent Document (THE PHYSICAL CHEMISTRY LETTERS 2013, 4, 502-507) Dots may be used. To emit fluorescent light partially retaining the polarization of the incident light means that when excitation light having a polarization degree of 99.9% is incident on the light conversion sheet, the fluorescence degree emitted by the light conversion sheet is not 0%. And the degree of polarization is preferably 10 to 99.9%, more preferably 80 to 99.9%. There is no particular upper limit, but in actual use, it includes the effect of eliminating the polarization caused by the manufacturing variation of the quantum rod and the variation in the film formation, so that the polarization of the emitted fluorescent light is substantially increased. The degree can be less than 99% or even less than 90%.

  The quantum dots may be added to the polymerizable composition in the form of particles, or may be added in the form of a dispersion dispersed in a solvent. The addition in the state of a dispersion is preferred from the viewpoint of suppressing the aggregation of quantum dot particles. The solvent used here is not particularly limited. Quantum dots can be added, for example, in an amount of about 0.01 to 10 parts by mass based on 100 parts by mass of the total amount of the polymerizable composition containing quantum dots.

(Radical polymerizable compound)
The radical polymerizable compound is not particularly limited. From the viewpoints of transparency, adhesion and the like of the cured film after curing, (meth) acrylate compounds such as monofunctional or polyfunctional (meth) acrylate monomers, and polymers and prepolymers thereof are preferred. In addition, in this specification, description of "(meth) acrylate" shall use at least one of acrylate and methacrylate, or any meaning. The same applies to “(meth) acryloyl” and the like.

Monofunctional (meth) acrylate monomers include acrylic acid and methacrylic acid, derivatives thereof, and more specifically, monomers having one polymerizable unsaturated bond of (meth) acrylic acid ((meth) acryloyl group) in the molecule. Can be mentioned. The compounds are listed below as specific examples thereof, but the present invention is not limited thereto.
Methyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, stearyl ( Alkyl (meth) acrylate having an alkyl group having 1 to 30 carbon atoms such as meth) acrylate; aralkyl (meth) acrylate having an aralkyl group having 7 to 20 carbon atoms such as benzyl (meth) acrylate; butoxyethyl (meth) ) An alkoxyalkyl (meth) acrylate having 2 to 30 carbon atoms in an alkoxyalkyl group such as acrylate; and a (monoalkyl or dialkyl) aminoalkyl group such as N, N-dimethylaminoethyl (meth) acrylate having a total carbon number of 1-2 Aminoalkyl (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, Octaethylene glycol monomethyl ether (meth) acrylate, nonaethylene glycol monomethyl ether (meth) acrylate, dipropylene glycol monomethyl ether (meth) acrylate, heptapropylene glycol monomethyl ether (meth) acrylate, tetraethylene glycol monoethyl Alkylene chains such as ether (meth) acrylates having 1 to 10 carbon atoms and terminal alkyl (Meth) acrylates of polyalkylene glycol alkyl ethers having 1 to 10 carbon atoms of ether; alkylene chains such as (meth) acrylate of hexaethylene glycol phenyl ether have 1 to 30 carbon atoms and terminal aryl ethers have 6 carbon atoms. Alicyclic structures such as cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, isobornyl (meth) acrylate, and methylene oxide-added cyclodecatriene (meth) acrylate; A (meth) acrylate having a total number of carbon atoms of 4 to 30; a fluorinated alkyl (meth) acrylate having a total number of carbon atoms of 4 to 30, 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) acrylate, hexaethylene glycol mono (meth) acrylate, octapropylene glycol mono (Meth) acrylate having a hydroxyl group such as (meth) acrylate or glycerol mono- or di (meth) acrylate; (meth) acrylate having a glycidyl group such as glycidyl (meth) acrylate; tetraethylene glycol mono (meth) acrylate, hexa Polyethylene glycol mono (meth) acrylates having an alkylene chain of 1 to 30 carbon atoms such as ethylene glycol mono (meth) acrylate and octapropylene glycol mono (meth) acrylate ) Acrylate; (meth) acrylamide, N, N- dimethyl (meth) acrylamide, N- isopropyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide, acryloyl morpholine (meth) acrylamide and the like.

  As the monofunctional (meth) acrylate monomer, an alkyl (meth) acrylate having 4 to 30 carbon atoms is preferably used, and an alkyl (meth) acrylate having 12 to 22 carbon atoms is preferably used to improve the dispersibility of quantum dots. From the viewpoint of, it is more preferable. As the dispersibility of the quantum dots improves, the amount of light perpendicular to the emission surface from the wavelength conversion layer increases, which is effective in improving the front luminance and the front contrast. Specifically, monofunctional (meth) acrylate monomers include butyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, oleyl (meth) acrylate, stearyl (meth) acrylate, and 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 preferable. Among them, lauryl (meth) acrylate, oleyl (meth) acrylate, and stearyl (meth) acrylate are particularly preferable.

In addition, the monofunctional (meth) acrylate compound is selected from the group consisting of a hydroxyl group and an aryl group from the viewpoint of further reducing the oxygen transmission coefficient of the wavelength conversion layer and improving the adhesion to another layer or member. It is also preferable to use a monofunctional (meth) acrylate compound having one or more groups.
As a group which a monofunctional (meth) acrylate compound has, a hydroxy group and a phenyl group are preferred. Preferred specific compounds include benzyl acrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, 1,4-cyclohexanedimethanol monoacrylate, 2-hydroxy-3-phenoxypropyl acrylate, and 4-hydroxybutyl acrylate.

A monomer having one polymerizable unsaturated bond ((meth) acryloyl group) of (meth) acrylic acid in one molecule and a polyfunctional (meth) acrylate monomer having two or more (meth) acryloyl groups in one molecule They can be used together.
Of the bifunctional or higher (meth) acrylate monomers, the bifunctional (meth) acrylate monomers include neopentyl glycol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, and tripropylene glycol di (meth) acrylate. ) Acrylate, ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate hydroxypivalate, polyethylene glycol di (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclo Pentenyloxyethyl (meth) acrylate, dicyclopentanyl di (meth) acrylate and the like are mentioned as preferred examples.

  Further, among the bifunctional or higher functional (meth) acrylate monomers, the trifunctional or higher functional (meth) acrylate monomers include ECH (epichlorohydrin) -modified glycerol tri (meth) acrylate and EO (ethylene oxide) -modified glycerol tri ( (Meth) acrylate, PO (propylene oxide) -modified glycerol tri (meth) acrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, EO-modified triphosphate phosphate, trimethylolpropane tri (meth) acrylate, caprolactone-modified trimethylolpropane tri ( (Meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, tris (acryloxy) Ethyl) isocyanurate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, dipentaerythritol hydroxypenta (meth) acrylate, alkyl-modified dipentaerythritol penta (Meth) acrylate, dipentaerythritol poly (meth) acrylate, alkyl-modified dipentaerythritol tri (meth) acrylate, ditrimethylolpropanetetra (meth) acrylate, pentaerythritolethoxytetra (meth) acrylate, pentaerythritoltetra (meth) acrylate And the like are preferred examples.

  In the quantum dot-containing polymerizable composition, a (meth) acrylate monomer having a ratio of weight average molecular weight Mw as a radical polymerizable compound to the number F of (meth) acryloyl groups per molecule, Mw / F of 200 or less, is used. Is also preferable. Mw / F is more preferably 150 or less, and most preferably 100 or less. The (meth) acrylate monomer having a low Mw / F can reduce the oxygen permeability of the wavelength conversion layer formed by curing the polymerizable composition containing quantum dots, and as a result, the heat resistance and light resistance of the wavelength conversion member It is because it can improve. Further, the use of a (meth) acrylate monomer having a small Mw / F is also preferable in that the crosslink density of the polymer in the wavelength conversion layer can be increased and breakage of the wavelength conversion layer can be prevented.

In addition, the weight average molecular weight in this specification is a value obtained by converting a value measured by gel permeation chromatography (GPC) into polystyrene. Examples of specific measurement conditions for the weight average molecular weight include the following measurement conditions. The weight average molecular weight described in the examples described below is a value measured under the following conditions.
GPC device: HLC-8120 (manufactured by Tosoh Corporation)
Column: TSK gel Multipore HXL-M (7.8 mm ID (inner diameter) x 30.0 cm, manufactured by Tosoh Corporation)
Eluent: tetrahydrofuran (THF)

  Specific examples of the (meth) acrylate monomer having Mw / F of 200 or less include pentaerythritol triacrylate, pentaerythritol tetraacrylate, trimethylolpropane trimethacrylate, dipentaerythritol hexaacrylate, and tricyclodecane dimethanol diacrylate. Acrylate and the like.

The amount of the polyfunctional (meth) acrylate monomer used is preferably 5 parts by mass or more from the viewpoint of coating film strength, based on 100 parts by mass of the total amount of the polymerizable compound contained in the quantum dot-containing polymerizable composition. Preferably, from the viewpoint of suppressing gelation of the composition, the content is preferably 95 parts by mass or less.
The radical polymerizable compound is preferably contained in an amount of 10 to 99.9 parts by mass, more preferably 50 to 99.9 parts by mass, based on 100 parts by mass of the total amount of the quantum dot-containing polymerizable composition. Is more preferable, and it is particularly preferable that it is contained in an amount of 80 to 99 parts by mass.

(Ring-opening polymerizable compound)
In another preferred embodiment of the present invention, a compound containing an epoxy group can be used as a polymerizable compound for forming an organic matrix, and one or two alicyclic epoxy groups are contained in one molecule. Preferably, a compound is used.
The alicyclic epoxy compound may be only one kind or two or more kinds having different structures. In the following, when two or more types of alicyclic epoxy compounds having different structures are used, the content related to the alicyclic epoxy compound refers to the total content of these. The alicyclic epoxy compound has better curability by light irradiation than the aliphatic epoxy compound. The use of a polymerizable compound having excellent photocurability is advantageous not only in improving productivity but also in that a layer having uniform physical properties can be formed on the light irradiation side and the non-irradiation side. Thereby, curling of the wavelength conversion layer can be suppressed and a wavelength conversion member having uniform quality can be provided. In general, epoxy compounds also tend to have a small curing shrinkage during photocuring.

  The alicyclic epoxy compound has at least one alicyclic epoxy group. Here, the alicyclic epoxy group means a monovalent substituent having a condensed ring between an epoxy ring and a saturated hydrocarbon ring, and preferably a monovalent substituent having a condensed ring between an epoxy ring and a cycloalkane ring. It is. More preferred alicyclic epoxy compounds include those having one or more of the following structures in a molecule in which an epoxy ring and a cyclohexane ring are condensed.

  Two or more of the above structures may be contained in one molecule, and preferably one or two are contained in one molecule. Further, the above structure may have one or more substituents. Examples of the substituent include an alkyl group (for example, an alkyl group having 1 to 6 carbon atoms), a hydroxyl group, an alkoxy group (for example, an alkoxy group having 1 to 6 carbon atoms), a halogen atom (for example, a fluorine atom, a chlorine atom, and a bromine atom). Groups, amino groups, nitro groups, acyl groups, carboxyl groups and the like. The above structure is preferably unsubstituted.

  Further, the alicyclic epoxy compound may have a polymerizable functional group other than the alicyclic epoxy group. The polymerizable functional group refers to a functional group capable of causing a polymerization reaction by radical polymerization or cationic polymerization, and includes, for example, a (meth) acryloyl group. In addition, the compound which has a (meth) acryloyl group with an alicyclic epoxy group shall calculate the content mentioned later as an alicyclic epoxy compound.

  Commercial products that can be suitably used as the alicyclic epoxy compound include Celloxide 2000, Celloxide 2021P, Celloxide 3000, Celloxide 8000, Cyclomer M100, Eporide GT301, Eporide GT401, and Sigma-Aldrich Co., Ltd. of Daicel Chemical Industries, Ltd. -Vinylcyclohexene dioxide, D-limonene oxide of Nippon Terpene Chemical Co., Ltd., and Sansocizer E-PS of Shin Nippon Rika Co., Ltd. These can be used alone or in combination of two or more. Among them, the following alicyclic epoxy compounds A and B are particularly preferable from the viewpoint of improving the adhesion between the wavelength conversion layer and the adjacent layer. The alicyclic epoxy compound A can be obtained as a commercial product as Daicel Chemical Industries, Ltd. Celloxide 2021P. The alicyclic epoxy compound B can be obtained as a commercial product as CYCLOMER M100 from Daicel Chemical Industries, Ltd.

  Further, the alicyclic epoxy compound can also be produced by a known synthesis method. Although the synthesis method is not limited, for example, Maruzen KK Publishing, 4th edition Experimental Chemistry Course 20, Organic Synthesis II, 213-, 1992, Ed. by Alfred Hasfner, The Chemistry of Heterocyclic Compounds-Small Ring Heterocycles Part 3, Oxiranes, John 19, 29, Yen, Wince and Sons, Anc. No. 5, 42, 1986, Yoshimura, Adhesion, Vol. 30, No. 7, 42, 1986, Japanese Patent Application Laid-Open No. H11-100378, and Japanese Patent No. 2926262 can be synthesized.

--- Polymerizable compound usable in combination with alicyclic epoxy compound--
The polymerizable composition for the wavelength conversion layer may contain only one or more alicyclic epoxy compounds as the polymerizable compound, and one or more other polymerizable compounds together with one or more alicyclic epoxy compounds. May be included. Hereinafter, another polymerizable compound is also described as a second polymerizable compound.

As the second polymerizable compound, one or two or more of various polymerizable compounds having a polymerizable functional group other than a polyfunctional (meth) acrylate compound and a (meth) acryloyl group can be used. For example, a polyfunctional alcohol (meth) acryloyl ester compound can be mentioned.
The second polymerizable compound can be used, for example, in an amount of 1 part by mass or more, preferably 40 parts by mass or less, and more preferably 30 parts by mass, based on 100 parts by mass of the alicyclic epoxy compound contained in the polymerizable composition. It is more preferable to use it below.
In another embodiment, the second polymerizable compound can be used in an amount of, for example, 40 parts by mass or more and 300 parts by mass or less with respect to 100 parts by mass of the alicyclic epoxy compound; It can be not less than 200 parts by mass and not more than parts by mass.

  In another preferred embodiment of the present invention, the polymerizable compound is a mixture of a radical polymerizable compound and a ring-opening polymerizable compound, and the content of the ring-opening polymerizable compound in the total polymerizable compound is 0.05% by mass or more. 0.0% by mass or less, more preferably 0.10% by mass or more and 6.0% by mass or less. It should be noted that a compound having both a ring-opening polymerizable group and a radical polymerizable group in one molecule shall be treated as a ring-opening polymerizable compound in the above definition of the mass ratio. By using the polymerizable compound at this mass ratio, the variation in the initial light emission intensity when the phosphite triester compound described below is used in combination is small, and the reduction of the light emission intensity during storage at a high temperature of the wavelength conversion member is suppressed. Has excellent effects. In particular, it has a remarkable effect on suppressing a decrease in emission intensity when the wavelength conversion member is stored under high humidity. Although the specific action is not clear, the ring-opening polymerizable compound is present in the wavelength conversion layer or an acidic compound generated upon storage (including, for example, a decomposition product of the phosphite triester compound of the present application described later). It is presumed that the deterioration effect of preservation due to the above is suppressed.

Examples of the ring-opening polymerizable compound include an oxetane compound in addition to the alicyclic epoxy compound described above. The oxetane compound is not particularly limited as long as it has one or more oxetane structures in one molecule, and may have two or more oxetane structures in one molecule. Further, an oxetane structure and a (meth) acryloyl group can be contained in one molecule.
Specific examples of the compound include 2-ethylhexyloxetane (Alonoxetane OXT-212, manufactured by Toagosei Co., Ltd.), xylylenebisoxetane (Aronoxetane OXT-121, manufactured by Toagosei Co., Ltd.), 3-ethyl-3} [ [Methoxy] methyl} oxetane (Aron oxetane OXT-221 manufactured by Toagosei Co., Ltd.), (3-ethyloxetane-3-yl) methyl acrylate (OXE-10 manufactured by Osaka Organic Chemical Industry Co., Ltd.), (3-ethyloxetane-3) -Yl) methyl methacrylate (OXE-30 manufactured by Osaka Organic Chemical Industry Co., Ltd.) and the like.
Among these ring-opening polymerizable compounds, a compound having two or more ring-opening polymerizable groups in the molecule or a ring-opening polymerizable compound having a (meth) acryloyl group in the molecule is preferable. ) Epoxy compounds having an acryloyl group are more preferred.

(Phosphorous acid triester compound)
The present inventors have found that by adding a phosphite triester compound to a composition containing a quantum dot together with a polymerizable compound, the emission of the quantum dot can be stabilized. Further, the phosphite triester compound does not inhibit the polymerization of the polymerizable compound, and can provide sufficient physical strength of the obtained wavelength conversion member.

Examples of the phosphite triester compound used in the present invention include triphenyl phosphite, trisnonylphenyl phosphite, tricresyl phosphite, tris (2-ethylhexyl) phosphite, tridecyl phosphite, Trilauryl phosphite, tris (tridecyl) phosphite, trioleyl phosphite, diphenyl mono (2-ethylhexyl) phosphite, diphenyl monodecyl phosphite, diphenyl mono (tridecyl) phosphite, trilauryl trithiophosphite, tetra Phenyldipropylene glycol diphosphite, tetraphenyl (tetratridecyl) pentaerythritol tetraphosphite, tetra (C12-C15 alkyl) -4,4′-isopropylidenediphenylphosphite A mixture of bis (tridecyl) pentaerythritol diphosphite and bis (nonylphenyl) pentaerythritol diphosphite, bis (decyl) pentaerythritol diphosphite, bis (tridecyl) pentaerythritol diphosphite, tristearyl phosphite, Stearyl pentaerythritol diphosphite (PEP-8: softening point 50-62 ° C), tris (2,4-di-tert-butylphenyl) phosphite (2112: melting point 180-190 ° C), hydrogenated bisphenol A.penta Erythritol phosphite polymer (softening point: about 80 ° C), hydrogenated bisphenol A phenyl phosphite polymer (softening point: about 80 ° C), 2,2'-methylenebis (4,6-di-tert-butylphenyl)- 2-ethylhexyl phosphite (HP-10: melting point 146-152 ° C), bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite (PEP-24: melting point 160-178 ° C), bis (2,6-di- tert-butyl-4-methylphenyl) pentaerythritol diphosphite (PEP-36: melting point 234 to 240 ° C.), 6-tert-butyl-4- [3- (2,4,8,10-tetra-tert- Butyldibenzo [d, f] [1,3,2] dioxaphosphepin-6-yloxy) propyl] -o-cresol (Sumilyzer GP: melting point> 115 ° C.).

Specific product names include phosphites JP-360, JP-351, JP-3CP, JP-308E, JP-310, JP-312L, JP-333E, JP-318-, manufactured by Johoku Chemical Co., Ltd. O, JPM-308, JPM-311, JPM-313, JPS-312, JPP-100, JPP-613M, JA-805, JPP-88, JPE-10, JPE-13R, JP-13R, JP-318E, JP-2000PT, JP-650, JPH-3800, and HBP.
Adeka Co., Ltd. Adekastab phosphite antioxidant PEP-8, PEP-36, PEP-36A, HP-10, 2112, 2112RG, 1178, 1500, C, 135A, 3010 manufactured by Adeka Corporation.
Further, a processing stabilizer Sumilizer GP manufactured by Sumitomo Chemical Co., Ltd. may, for example, be mentioned.

Among these compounds, those in which the two ester portions of the phosphite triester are linked to each other and have a cyclic structure have a small variation in the initial light emission intensity and suppress the decrease in the light emission intensity when the wavelength conversion member is stored at a high temperature. It was found to have excellent effects. Further, at least one of the ester portions of the phosphite triester has an excellent effect of suppressing a decrease in emission intensity of the wavelength conversion member containing an aromatic group having a tertiary alkyl group when stored at a high temperature. I understood. Furthermore, it was found that one of the ester portions of the phosphite triester containing an aromatic group having a tertiary alkyl group and two ester portions connected to each other to form a cyclic structure was particularly excellent in effect.
In addition, from the viewpoint of suppressing a decrease in emission intensity after storage of the wavelength conversion member at a high temperature, the phosphite triester compound is preferably solid at room temperature (25 ° C), and has a softening point or a melting point of 40 ° C or higher. More preferably, the softening point or melting point is more preferably 60 ° C or higher, and particularly preferably, the melting point is 100 ° C or higher and 300 ° C or lower.

  The amount of the phosphite triester-based compound to be used is 0.001 to 10 parts by mass, preferably 0.005 to 5 parts by mass, more preferably 0.01 to 100 parts by mass in the quantum dot-containing matrix. ３3 parts by mass. When used in this range, the solubility in the matrix is excellent and the effect of thermal stability can be exhibited. Similarly, in the quantum dot-containing composition, 0.001 to 10 parts by mass, preferably 0.005 to 5 parts by mass, more preferably 0.01 to 3 parts by mass with respect to 100 parts by mass of the polymerizable compound for matrix formation. Department.

  The quantum dot-containing polymerizable composition of the present invention may contain additives such as an antioxidant and a hindered amine light stabilizer in addition to the phosphite triester compound.

  Particularly preferable examples of these additives include phenol-based, sulfur-based antioxidants, and hindered amine-based light stabilizers. Particularly, the combined use with phenol-based antioxidants is excellent in the effect of improving thermal stability. preferable.

  Examples of phenolic antioxidants include 2,6-di-tert-butyl-p-cresol, 2,6-diphenyl-4-octadecyloxyphenol, and stearyl (3,5-di-tert-butyl-4-hydroxy). Phenyl) -propionate, distearyl (3,5-di-tert-butyl-4-hydroxybenzyl) phosphonate, thiodiethylene glycol bis [(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,6- Hexamethylene bis [(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,6-hexamethylene bis [(3,5-di-tert-butyl-4-hydroxyphenyl) propionamide], 4,4'-thiobis (6-tert-butyl-m-cresol), 2,2'-methylenebis (4-methyl-6-tert. Butylphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), bis [3,3-bis (4-hydroxy-3-tert-butylphenyl) butyric acid] glycol ester, 4′-butylidenebis (6-tert-butyl-m-cresol), 2,2′-ethylidenebis (4,6-di-tert-butylphenol), 2,2′-ethylidenebis (4-tert-butyl-6- Tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, bis [2-tert-butyl-4-methyl-6- (2-hydroxy-3) -Tert-butyl-5-methylbenzyl) phenyl] terephthalate, 1,3,5-tris (2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate 1,3,5-tris (3,5-di-tert-butyl-4-hydroxylbenzyl) isocyanurate, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl)- 2,4,6-trimethylbenzene, 1,3,5-tris [(3,5-ditert-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanurate, tetrakis [methylene-3- (3 ′, 5 '-Di-tert-butyl-4'-hydroxyphenyl) propionate] methane, 2-tert-butyl-4-methyl-6- (2-acryloyloxy-3-tert-butyl-5-methylbenzyl) phenol, 3, 9-bis [1,1-dimethyl-2-{(3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl] -2,4,8,10-tetraoxaspiro [ 5.5] Undecane, triethylene glycol bis [(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], 2- [1- (2-hydroxy-3,5-ditert-pentylphenyl) [Ethyl] -4,6-ditertiary pentylphenyl acrylate and the like.

  Examples of the sulfur-based antioxidants include, for example, dialkylthiodipropionates such as dilauryl thiodipropionate, dimyristyl and distearyl, and β-alkyl mercapto such as polyols such as pentaerythritol tetra (β-dodecylmercaptopropionate). And propionates.

  Examples of the hindered amine-based light stabilizer include, for example, 2,2,6,6-tetramethyl-4-piperidylbenzoate and N- (2,2,6,6-tetramethyl-4-piperidyl) dodecylsuccinimide , 1-[(3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxyethyl] -2,2,6,6-tetramethyl-4-piperidyl- (3,5-di-tert-butyl-4 -Hydroxyphenyl) propionate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis (1,2 , 2,6,6-Pentamethyl-4-piperidyl) -2-butyl-2- (3,5-ditert-butyl-4-hydroxybenzyl) malonate, N, N'-bis (2,2, , 6-tetramethyl-4-piperidyl) hexamethylenediamine, tetra (2,2,6,6-tetramethyl-4-piperidyl) butanetetracarboxylate, tetra (1,2,2,6,6-pentamethyl- 4-piperidyl) butanetetracarboxylate, bis (2,2,6,6-tetramethyl-4-piperidyl) di (tridecyl) butanetetracarboxylate, bis (1,2,2,6,6-pentamethyl- 4-piperidyl) di (tridecyl) butanetetracarboxylate, 3,9-bis [1,1-dimethyl-2- {tris (2,2,6,6-tetramethyl-4-piperidyloxycarbonyloxy) butyl Carbonyloxydiethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane, 3,9-bis [1,1- Methyl-2- {tris (1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyloxy) butylcarbonyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane , 1,5,8,12-tetrakis [4,6-bis {N- (2,2,6,6-tetramethyl-4-piperidyl) butylamino} -1,3,5-triazin-2-yl ] -1,5,8,12-tetraazadodecane, 1- (2-hydroxyethyl) -2,2,6,6-tetramethyl-4-piperidinol / dimethyl succinate condensate, 2-tert-octylamino -4,6-dichloro-s-triazine / N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) hexamethylenediamine condensate, N, N′-bis (2,2 6,6-tetrame Tyl-4-piperidyl) hexamethylenediamine / dibromoethane condensate.

  The amount of the compound that can be used in combination with the phosphite triester is 0.001 to 10 parts by mass, preferably 0.005 to 5 parts by mass, and more preferably 100 parts by mass of the matrix in the quantum dot-containing matrix. 0.01 to 3 parts by mass. In the quantum dot-containing composition, the amount is 0.001 to 10 parts by mass, preferably 0.005 to 5 parts by mass, more preferably 0.01 to 3 parts by mass with respect to 100 parts by mass of the polymerizable compound for matrix formation. .

(Polymerization initiator)
The quantum dot-containing polymerizable composition may contain a known radical initiator or cationic polymerization initiator as a polymerization initiator. For the polymerization initiator, for example, JP-A-2013-043382, paragraph 0037 and JP-A-2011-159924, paragraphs 0040 to 0042 can be referred to. Among them, the polymerization initiator is preferably a photopolymerization initiator, and as the photopolymerization initiator, a monoacylphosphine oxide compound is preferably used. Examples of the monoacylphosphine oxide-based compound include ethoxyphenyl (2,4,6-trimethylbenzoyl) phosphine oxide and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide.

  The amount of the photopolymerization initiator is preferably from 0.1% by mass to 10% by mass with respect to the total mass of the wavelength conversion layer. It is more preferably from 3% by mass to 9% by mass, and further preferably from 4% by mass to 8% by mass.

  It is preferable that the amount of the polymerization initiator is in the above range, because a decrease in luminance during storage at a high temperature can be suppressed. Further, it is preferable to use a monoacylphosphine oxide-based compound as a polymerization initiator because a decrease in initial luminance and an increase in half width can be suppressed.

(Silane coupling agent)
The quantum dot-containing polymerizable composition may further include a silane coupling agent, and the wavelength conversion layer formed from the polymerizable composition including the silane coupling agent may have a layer adjacent to the silane coupling agent. Since the adhesion is strong, more excellent light resistance can be exhibited. This is mainly because the silane coupling agent contained in the wavelength conversion layer forms a covalent bond with the surface of an adjacent layer or a component of the layer by a hydrolysis reaction or a condensation reaction. At this time, it is also preferable to provide an inorganic layer described later as an adjacent layer. Further, when the silane coupling agent has a reactive functional group such as a radical polymerizable group, the silane coupling agent can form a crosslinked structure with a monomer component constituting the wavelength conversion layer, and can also improve adhesion between the wavelength conversion layer and an adjacent layer. Can contribute. In the present specification, the silane coupling agent contained in the wavelength conversion layer is used in a sense that the silane coupling agent in the form after the reaction as described above is included.
As the silane coupling agent, a known silane coupling agent can be used without any limitation. As a preferable silane coupling agent from the viewpoint of adhesion, a silane coupling agent represented by the general formula (1) described in JP-A-2013-43382 can be exemplified. For details, the description in paragraphs 0011 to 0016 of JP-A-2013-43382 can be referred to. The amount of the additive such as the silane coupling agent is not particularly limited, and can be set as appropriate.

(solvent)
The quantum dot polymerizable composition may contain a solvent as needed. The type and amount of the solvent used in this case are not particularly limited. For example, one or a mixture of two or more organic solvents can be used as the solvent.

(Method of forming wavelength conversion layer)
The wavelength conversion layer can be formed by applying the polymerizable composition containing a quantum dot on an appropriate substrate, and then performing polymerization treatment such as light irradiation and heating to polymerize and cure. Known coating methods include curtain coating, dip coating, spin coating, print coating, spray coating, slot coating, roll coating, slide coating, blade coating, gravure coating, and wire bar method. Coating method.
Curing conditions can be appropriately set according to the type of the polymerizable compound used and the composition of the polymerizable composition. When the polymerizable composition containing a quantum dot is a composition containing a solvent, a drying treatment may be performed to remove the solvent before performing the polymerization treatment.

  The curing of the quantum dot-containing polymerizable composition may be performed in a state where the quantum dot-containing polymerizable composition is sandwiched between two substrates. One embodiment of a process for manufacturing a wavelength conversion member including such a polymerization treatment will be described below with reference to the drawings. However, the present invention is not limited to the following embodiments.

  FIG. 2 is a schematic configuration diagram of an example of the wavelength conversion member manufacturing apparatus 100, and FIG. 3 is a partially enlarged view of the manufacturing apparatus shown in FIG. In the manufacturing process of the wavelength conversion member using the manufacturing apparatus 100 illustrated in FIGS. 2 and 3, the quantum dot-containing polymerizable composition is formed on the surface of a first substrate (hereinafter, referred to as “first film”) that is continuously conveyed. And forming a coating film, and laminating (overlapping) a second substrate (hereinafter, also referred to as a “second film”) which is continuously conveyed on the coating film. A step of sandwiching the coating film between the film and the second film, and backing up any one of the first film and the second film in a state where the coating film is sandwiched between the first film and the second film. Forming a wavelength conversion layer (cured layer) by polymerizing and curing the coating film by irradiating the film with a roller and irradiating light while continuously transporting the film. By using a barrier film having a barrier property against oxygen and moisture as one of the first base material and the second base material, a wavelength conversion member whose one surface is protected by the barrier film can be obtained. Moreover, by using a barrier film as each of the first base material and the second base material, a wavelength conversion member in which both surfaces of the wavelength conversion layer are protected by the barrier film can be obtained.

  More specifically, first, the first film 10 is continuously conveyed to the coating unit 20 from a sending device (not shown). For example, the first film 10 is sent from the feeder at a transport speed of 1 to 50 m / min. However, it is not limited to this transport speed. When being sent out, for example, a tension of 20 to 150 N / m, preferably 30 to 100 N / m is applied to the first film 10.

  In the application section 20, a quantum dot-containing polymerizable composition (hereinafter, also referred to as “application liquid”) is applied to the surface of the first film 10 that is continuously conveyed, and a coating film 22 (see FIG. 3) is formed. Is done. In the application section 20, for example, a die coater 24 and a backup roller 26 arranged opposite to the die coater 24 are installed. The surface of the first film 10 opposite to the surface on which the coating film 22 is formed is wound around a backup roller 26, and the coating liquid is applied to the surface of the continuously transported first film 10 from the discharge port of the die coater 24. Thus, a coating film 22 is formed. Here, the coating film 22 refers to the quantum dot-containing polymerizable composition applied on the first film 10 before the polymerization treatment.

  In the present embodiment, the die coater 24 to which the extrusion coating method is applied is shown as the coating apparatus, but the coating apparatus is not limited to this. For example, an application apparatus to which various methods such as a curtain coating method, a rod coating method, and a roll coating method are applied can be used.

  The first film 10 having passed through the coating unit 20 and having the coating film 22 formed thereon is continuously transported to the laminating unit 30. In the laminating unit 30, the second film 50 that is 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.

  The laminating unit 30 is provided with a laminating roller 32 and a heating chamber 34 surrounding the laminating roller 32. 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 laminating roller 32. The first film 10 on which the coating film 22 is formed is wound around the backup roller 62 on the surface opposite to the surface on which the coating film 22 is formed, and is continuously transported to the lamination position P. The lamination position P means 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 if wrinkles occur in the first film 10, the wrinkles are corrected by the backup roller 62 before reaching the lamination position P and can be removed. Therefore, it is preferable that the distance L1 between the position (contact position) at which the first film 10 is wound around the backup roller 62 and the lamination position P is long, for example, 30 mm or more, and the upper limit is usually It is determined by the diameter of the backup roller 62 and the pass line.

  In the present embodiment, the lamination of the second film 50 is performed by the backup roller 62 and the laminating roller 32 used in the polymerization processing unit 60. That is, the backup roller 62 used in the curing unit 60 is also used as a roller used in the laminating unit 30. However, the present invention is not limited to the above-described embodiment, and a laminating roller may be provided in the laminating section 30 separately from the backup roller 62 so that the laminating section 30 does not double as the backup roller 62.

  By using the backup roller 62 used in the curing unit 60 in the laminating unit 30, the number of rollers can be reduced. Further, the backup roller 62 can also be used as a heat roller for the first film 10.

  The second film 50 sent from a not-shown sending device is wound around the laminating roller 32 and is continuously conveyed between the laminating 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 laminating position P. Thus, the coating film 22 is sandwiched between the first film 10 and the second film 50. Lamination refers to laminating and laminating the second film 50 on the coating film 22.

  The distance L2 between the laminating roller 32 and the backup roller 62 is a value of the total thickness of the first film 10, the wavelength conversion layer (cured layer) 28 obtained by polymerizing and curing the coating film 22, and the second film 50. It is preferable that it is above. Further, it is preferable that L2 is equal to or less than a 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 setting the distance L2 to be equal to or less than the length obtained by adding 5 mm to the total thickness, it is possible to prevent bubbles from entering between the second film 50 and the coating film 22. Here, the distance L2 between the laminating roller 32 and the backup roller 62 refers to the shortest distance between the outer peripheral surface of the laminating roller 32 and the outer peripheral surface of the backup roller 62.

  The rotational accuracy of the laminating roller 32 and the backup roller 62 is 0.05 mm or less in radial deflection, preferably 0.01 mm or less. The smaller the radial run-out, the smaller the thickness distribution of the coating film 22 can be.

  Further, 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 processing section 60 and the temperature of the first film 10 are reduced. The difference 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.

  When the heating chamber 34 is provided, it is preferable to heat the first film 10 and the second film 50 in the heating chamber 34 in order to reduce the difference from the temperature of the backup roller 62. For example, hot air is supplied to the heating chamber 34 by a hot air generator (not shown), so that the first film 10 and the second film 50 can be heated.

  The first film 10 may be heated by the backup roller 62 by being wound around the backup roller 62 whose temperature has been adjusted.

On the other hand, the second film 50 can be heated by the laminating roller 32 by using the laminating 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 a state where the coating film 22 is sandwiched between the first film 10 and the second film 50, the coating film 22 is continuously conveyed to the polymerization processing unit 60. In the embodiment shown in the drawing, the polymerization treatment in the polymerization treatment section 60 is performed by light irradiation. However, when the polymerizable compound contained in the quantum dot-containing polymerizable composition is polymerized by heating, blowing of hot air is performed. By such heating, the polymerization treatment can be performed.

A light irradiation device 64 is provided at the backup roller 62 and at a position facing the backup roller 62. The first film 10 and the second film 50 sandwiching the coating film 22 are continuously transported between the backup roller 62 and the light irradiation device 64. The light irradiated by the light irradiation device may be determined according to the type of the photopolymerizable compound contained in the quantum dot-containing polymerizable composition, and an example is ultraviolet light. Here, the ultraviolet light refers to light having a wavelength of 280 to 400 nm. As a light source that generates ultraviolet light, 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 light irradiation amount may be set within a range in which the polymerization and curing of the coating film can proceed. For example, ultraviolet light having an irradiation amount of 100 to 10000 mJ / cm ² can be applied to the coating film 22 as an example.

  In the polymerization processing unit 60, the first film 10 is wound around the backup roller 62 in a state where the coating film 22 is sandwiched between the first film 10 and the second film 50, and the light irradiation device 64 is continuously transported. The light is irradiated from above to cure the coating film 22 to form the wavelength conversion layer (cured layer) 28.

  In the present embodiment, the first film 10 is wound around the backup roller 62 and transported continuously, but the second film 50 may be wound around the backup roller 62 and transported continuously.

  Wrapping 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 wrap 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. What is necessary is just to wind around the backup roller 62 at least during irradiation of ultraviolet rays.

  The backup roller 62 includes a cylindrical main body, and rotating shafts disposed at both ends of the main body. The main body of the backup roller 62 has, for example, a diameter of 200 to 1000 mm. There is no limitation on the diameter φ of the backup roller 62. In consideration of the curl deformation of the laminated film, the equipment cost, and the rotation accuracy, the diameter is preferably φ300 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 determined in consideration of the heat generated during light irradiation, the curing efficiency of the coating film 22, and the occurrence of wrinkle deformation of the first film 10 and the second film 50 on the backup roller 62. , Can be determined. For example, the backup roller 62 is preferably set in a temperature range of 10 to 95 ° C, and more preferably 15 to 85 ° C. Here, the temperature relating to the roller refers to 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 the cured layer 28 by light irradiation, and the 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 separated from the backup roller 62 by the separation roller 80. The wavelength conversion member 70 is continuously conveyed to a winding machine (not shown), and then the wavelength conversion member 70 is wound into a roll by the winding machine.

  As described above, one embodiment of the manufacturing process of the wavelength conversion member has been described, but the present invention is not limited to the above embodiment. For example, the wavelength conversion layer by applying the quantum dot-containing polymerizable composition on a substrate, without drying a further substrate without laminating a further substrate thereon, followed by a polymerization treatment if necessary. (Curing layer) may be prepared. On the produced wavelength conversion layer, one or more other layers can be laminated 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 15 to 400 µm. When used for a small to medium-sized display, it is preferably a thin layer, preferably 1 to 100 μm, more preferably 10 to 70 μm, and most preferably 15 to 55 μm. In applications where it is important to increase the rigidity of the sheet itself rather than the need for thinning, such as a large display, the thickness is preferably 15 to 500 μm, more preferably 40 to 300 μm, and most preferably 50 to 200 μm.
Further, the wavelength conversion layer may have a stacked structure of two or more layers, and may include two or more kinds of quantum dots exhibiting different 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 5 to 250 μm, and still more preferably 15 to 250 μm. The range is 100 μm. It is preferable that the thickness be 1 μm or more, since a high wavelength conversion effect can be obtained. Further, when the thickness is 500 μm or less, the backlight unit can be made thinner when incorporated in the backlight unit, which is preferable.

<Other layers and substrates>
The wavelength conversion member may have a configuration including only the wavelength conversion layer or a base material described later in addition to the wavelength conversion layer. Alternatively, at least one main surface of the wavelength conversion layer may have at least one layer selected from the group consisting of an inorganic layer and an organic layer. Examples of such an inorganic layer and an organic layer include an inorganic layer and an organic layer constituting a barrier film described later. From the viewpoint of maintaining the luminous efficiency, it is preferable that both main surfaces of the wavelength conversion layer include at least one layer selected from the group consisting of an inorganic layer and an organic layer. This is because such a layer can prevent oxygen from entering the wavelength conversion layer from the main surface. In one embodiment, the inorganic layer and the organic layer are preferably included as an adjacent layer directly in contact with the main surface of the wavelength conversion layer. In another embodiment, the main surface of the wavelength conversion layer and another layer may be bonded via a known adhesive layer. In one aspect, the wavelength conversion member may be such that the entire surface of the wavelength conversion layer is covered with the coating (that is, may be sealed), but from the viewpoint of productivity, the entire surface is covered with the coating. For example, it is preferable that both main surfaces are protected by another layer, preferably by a barrier film described later, and the side surfaces are exposed to the atmosphere. Even in such a state, since the wavelength conversion layer does not easily pass oxygen, deterioration of the quantum dots due to oxygen can be suppressed.

(Base material)
The wavelength conversion member may have a base material for improving strength, forming a film easily, and the like. The substrate may be in direct contact with the wavelength conversion layer. The base material may be included in the wavelength conversion member one or more, and the wavelength conversion member may have a structure in which the base material, the wavelength conversion layer, and the base material are laminated in this order. Good. When the wavelength conversion member includes two or more substrates, the substrates may be the same or different. The substrate is preferably transparent to visible light. Here, "transparent to visible light" means that the line transmittance in the visible light region is 80% or more, preferably 85% or more. The light transmittance used as a measure of transparency is determined by the method described in JIS-K7105, that is, the total light transmittance and the amount of scattered light are measured using an integrating sphere light transmittance measurement device, and the diffuse transmittance is calculated from the total light transmittance. It can be calculated by subtracting the rate.

  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 viewpoint of gas barrier properties, impact resistance and the like.

  Further, the base material can be used as one or both of a first base material and a second base material described later.

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

The barrier film usually needs to contain at least an inorganic layer, and may be a film containing a support film and an inorganic layer. With respect to the support film, for example, JP-A-2007-290369, paragraphs 0046 to 0052 and JP-A-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 a support film. As an example, a laminated structure of a support film / organic layer / organic layer, a laminated structure of a support film / organic layer / organic layer, a laminated structure of a support film / organic layer / inorganic layer / organic layer (here, a two-layer structure) One or both of the thickness and the composition of the organic layer may be the same or different). By stacking a plurality of layers in this manner, the barrier property can be further enhanced.On the other hand, as the number of layers to be stacked increases, the light transmittance of the wavelength conversion member tends to decrease. It is desirable to increase the number of layers within a range that can maintain a high light transmittance. 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: trade name, manufactured by MOCON) under the conditions of a measurement temperature of 23 ° C. and a relative humidity of 90%. is there. The barrier film preferably has a total light transmittance of 80% or more in the visible light region. The visible light region refers to a wavelength region of 380 to 780 nm, and the total light transmittance indicates an average value of light transmittance over the visible light region. The oxygen permeability of 1 cm ³ / (m ² · day · atm) is 1.14 × 10 ^-1 fm / Pa · s when converted to the SI unit system.
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 light region is more preferably 90% or more. The oxygen permeability is preferably as low as possible, and the total light transmittance in the visible light region is preferably as high as possible.

(Inorganic layer)
The “inorganic layer” is a layer containing an inorganic material as a main component, and is preferably a layer formed of only an inorganic material. On the other hand, the organic layer is a layer containing an organic material as a main component, preferably a layer in which the organic material accounts for 50% by mass or more, further 80% by mass or more, particularly 90% by mass or more. I do.
The inorganic material constituting the inorganic layer is not particularly limited, and for example, metals or various inorganic compounds such as inorganic oxides, nitrides, and oxynitrides can be used. As elements constituting the inorganic material, silicon, aluminum, magnesium, titanium, tin, indium and cerium are preferable, and one or more of these 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, a metal film such as an aluminum film, a silver film, a tin film, a chromium film, a nickel film, and a titanium film may be provided as the inorganic layer.

Among the above materials, silicon nitride, silicon oxide, or silicon oxynitride is particularly preferred. This is because the inorganic layer made of such a material has good adhesion to the organic layer, so that the barrier property can be further enhanced.
The method for forming the inorganic layer is not particularly limited, and for example, various film forming methods capable of evaporating or scattering a film forming material and depositing the material on a surface to be deposited can be used.

  Examples of the method for forming the inorganic layer include a vacuum deposition method of heating and depositing an inorganic material such as an inorganic oxide, an inorganic nitride, an inorganic oxynitride, and a metal; using an inorganic material as a raw material, and introducing oxygen gas. Oxidation reaction deposition method of oxidizing and depositing by sputtering; sputtering method of depositing by sputtering by using an inorganic material as a target material and introducing argon gas and oxygen gas; plasma generated by a plasma gun on the inorganic material In the case of forming a deposited film of silicon oxide by a physical vapor deposition method such as an ion plating method in which the film is heated and vapor-deposited by a beam, or a plasma-enhanced chemical vapor deposition method using an organic silicon compound as a raw material when a deposited film of silicon oxide is formed. (Chemical Vapor Deposition method) and the like. Vapor deposition may be performed on the surface using 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 by a low-temperature plasma chemical vapor deposition method. Specific examples of the organosilicon compound include 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, vinyltrimethylsilane, hexamethyldisilane, methylsilane, dimethylsilane, trimethylsilane, diethylsilane, propyl Examples include silane, phenylsilane, vinyltriethoxysilane, tetramethoxysilane, phenyltriethoxysilane, methyltriethoxysilane, and octamethylcyclotetrasiloxane. Further, among the above organosilicon compounds, it is preferable to use tetramethoxysilane (TMOS) and hexamethyldisiloxane (HMDSO). This is because these are excellent in handleability and characteristics of the deposited 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. When the thickness of the inorganic layer is within the above-described range, it is possible to provide a wavelength conversion member that can suppress reflection in the inorganic layer and achieve higher light transmittance while realizing good barrier properties. Because.

  In one aspect of the wavelength conversion member, 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 one embodiment, at least one main surface of the wavelength conversion layer is preferably 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 (front surface, back surface) of the wavelength conversion layer disposed on the viewing side or the backlight side when the wavelength conversion member is used. The same applies to the main surfaces of other layers and members. Further, between the inorganic layer and the organic layer, between the two inorganic layers, or between the two organic layers may be bonded with a known adhesive layer. From the viewpoint of improving the light transmittance, the smaller the adhesive layer, the more preferable it is. In one embodiment, the inorganic layer and the organic layer are preferably in direct contact.

(Organic layer)
As the organic layer, JP-A 2007-290369, paragraphs 0020 to 0042, and JP-A 2005-096108, paragraphs 0074 to 0105 can be referred to. In one embodiment, the organic layer preferably contains a cardo polymer. Thereby, the adhesion between the organic layer and the adjacent layer, particularly the adhesion between the inorganic layer and the inorganic layer is improved, and more excellent gas barrier properties can be realized. For details of the cardo polymer, see paragraphs 0085 to 0095 of JP-A-2005-096108. The thickness of the organic layer is preferably in the range of 0.05 μm to 10 μm, particularly preferably in the range of 0.5 to 10 μm. When the organic layer is formed by a wet coating method, the thickness of the organic layer is preferably in the range of 0.5 to 10 μm, particularly preferably in the range of 1 to 5 μm. When formed by a dry coating method, the thickness is preferably in the range of 0.05 μm to 5 μm, particularly preferably in the range of 0.05 μm to 1 μm. This is because when the thickness of the organic layer formed by the wet coating method or the dry coating method is within the above range, the adhesion to the inorganic layer can be further improved.

  In the present specification, a polymer refers to a polymer obtained by polymerizing two or more compounds that are the same or different from each other by a polymerization reaction, and is used in a meaning including an oligomer, and the molecular weight is not particularly limited. Further, the polymer may be a polymer having a polymerizable group, which can be further polymerized by being subjected to a polymerization treatment according to the type of the polymerizable group such as heating or light irradiation. The polymerizable compound such as the alicyclic epoxy compound, the monofunctional (meth) acrylate compound, and the polyfunctional (meth) acrylate compound described above may correspond to the polymer in the above meaning.

  Further, the organic layer may be a cured layer obtained by curing a polymerizable composition containing a (meth) acrylate polymer. The (meth) acrylate polymer is a polymer containing one or more (meth) acryloyl groups in one 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 in one molecule can be given. Hereinafter, a (meth) acrylate polymer containing one or more urethane bonds in one molecule will be referred to as a urethane bond-containing (meth) acrylate polymer. When the barrier layer includes two or more organic layers, a cured layer obtained by curing a polymerizable composition containing a urethane bond-containing (meth) acrylate polymer and another organic layer may be included. In one embodiment, the organic layer that is in direct contact with one or both main surfaces of the wavelength conversion layer is preferably a cured layer obtained by curing a polymerizable composition containing a urethane bond-containing (meth) acrylate polymer.

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

  It is also preferable that at least one terminal of the side chain having a urethane bond contains a (meth) acryloyl group. More preferably, all the side chains having a urethane bond contain a (meth) acryloyl group. Here, the (meth) acryloyl group contained in the terminal is more preferably an acryloyl group.

  The urethane bond-containing (meth) acrylate polymer can be generally obtained by graft copolymerization, but is not particularly limited. The acrylic main chain and the structural unit having 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 include a plurality of types of side chains in which structural units having urethane bonds are bonded via different linking groups (including direct bonds).

  The urethane bond-containing (meth) acrylate polymer may have a side chain other than the structural unit having a urethane bond. Examples of the other side chain include a linear or branched alkyl group. As the linear or branched alkyl group, a linear alkyl group having 1 to 6 carbon atoms is preferable, an n-propyl group, an ethyl group, or a methyl group is more preferable, and a methyl group is further preferable. The other side chain may have a different structure. This is 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 one or more, and is preferably two 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 even more preferably 15,000 or more. Further, 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 at least 500, more preferably at least 600, even more preferably at least 7,00, and the acrylic equivalent is at most 5,000. , Preferably 3,000 or less, more preferably 2,000 or less. The acrylic equivalent is a value obtained by dividing the number of (meth) acryloyl groups in one molecule by the weight average molecular weight.

  As the urethane bond-containing (meth) acrylate polymer, a polymer synthesized by a known method may be used, or a commercially available product may be used. Examples of commercially available products include UV-curable acrylic urethane polymer (8BR series) manufactured by Taisei Fine Chemical Co., Ltd. The urethane bond-containing (meth) acrylate polymer is preferably contained in an amount of 5 to 90% by mass, more preferably 10 to 80% by mass, based on 100% by mass of the total solid content of the polymerizable composition for forming the organic layer. Is more preferred.

In the curable compound used to form the organic layer, one or more urethane bond-containing (meth) acrylate polymers and one or more other polymerizable compounds may be used in combination. As the other polymerizable compound, a compound having an ethylenically unsaturated bond at a terminal or a side chain is preferable. Examples of the compound having an ethylenically unsaturated bond at a terminal or a side chain include a (meth) acrylate compound, an acrylamide compound, a styrene compound, and maleic anhydride. A (meth) acrylate compound is preferable, and an acrylate compound. Is 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, for example, compounds described in paragraphs 0024 to 0036 of JP-A-2013-43382 or paragraphs 0036 to 0048 of JP-A-2013-43384.
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 can include a known additive together with one or more polymerizable compounds. An example of such an additive includes an organometallic coupling agent. For details, reference can be made to the above description. The organic metal coupling agent is preferably 0.1 to 30% by mass, more preferably 1 to 20% by mass, when the total solid content of the polymerizable composition used to form the organic layer is 100% by mass.

  Further, examples of the additive include a polymerization initiator. When a polymerization initiator is used, the content of the polymerization initiator in the polymerizable composition is preferably 0.1 mol% or more of the total amount of the polymerizable compound, and is preferably 0.5 to 5 mol%. More preferred. Examples of the photopolymerization initiator include Irgacure (registered trademark) series available from BASF (eg, Irgacure 651, Irgacure 754, Irgacure 184, Irgacure 2959, Irgacure 907, Irgacure 369, Irgacure 379, Irgacure 819, etc. ), Darocure® series (eg, Darocure TPO, Darocure 1173, etc.), Quantacure PDO, Ezacure series commercially available from Lamberti (eg, Ezacure TZM, Ezacure TZT, Ezacure KTO46, etc.).

  The curing of the polymerizable composition for forming the organic layer may be performed by a treatment (light irradiation, heating, or the like) according to 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 types 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 can be made to JP-A-2007-290369, JP-A-2005-096108, and further description of US2012 / 0113672A1.

  A known adhesive layer may be used to bond between an organic layer and an inorganic layer, between two organic layers, or between two inorganic layers. From the viewpoint of improving the light transmittance, the smaller the adhesive layer, the more preferable it is.

[Light scattering function]
The wavelength conversion member can have a light scattering function in order to efficiently extract the fluorescence of the quantum dots to the outside. The light scattering function may be provided in the wavelength conversion layer, or a layer having a light scattering function may be separately provided as the light scattering layer.
As one embodiment, it is also preferable to add light scattering particles inside the wavelength conversion layer.
As another aspect, it is also preferable to provide a light scattering layer on the surface of the wavelength conversion layer. Scattering in the light scattering layer may depend on light scattering particles, or may depend on surface irregularities.

(Light scattering particles, etc.)
In the present specification, “light scattering particles” refer to particles having a particle size of 0.10 μm or more. Light scattering is caused by optical inhomogeneities in the layers. Particles having a sufficiently small particle size do not significantly reduce the optical uniformity of the layer even if they are contained, whereas particles having a particle size of 0.10 μm or more optically impair the layer. Particles that can be homogenized, thereby causing light scattering. It is preferable that light scattering particles are included in the wavelength conversion layer from the viewpoint of improving luminance.
The above-mentioned particle size is a value obtained by observing with a scanning electron microscope (Scanning Electron Microscope; SEM). Specifically, after the cross section of the wavelength conversion layer is photographed at a magnification of 5,000, the primary particle diameter is measured from the obtained image. For particles that are not spherical, the average value of the length of the major axis and the length of the minor axis is determined, and this is adopted as the primary particle diameter. The primary particle diameter determined in this way is defined as the particle size of the above-mentioned particles. The average particle size of the light scattering particles is the arithmetic average of the particle sizes of 20 particles randomly extracted from particles having a particle size of 0.10 μm or more in a captured image. The average particle size of the light-scattering particles shown in the examples described below is a value obtained by observing and measuring the cross section of the wavelength conversion layer using Hitachi High-Tech S-3400N as a scanning electron microscope. .

  As described above, the particle size of the light scattering particles is 0.10 μm or more. In light 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 0.10 to 10.0 μm, and more preferably 0.20 to 4 μm. More preferably, it is 0.0 μm. Further, in order to further improve the luminance and adjust the distribution of the luminance with respect to the viewing angle, two or more kinds 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. For example, 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, it is preferable that the refractive index of the light scattering particles and the other parts in the matrix of the wavelength conversion layer be different, and from this viewpoint, the silicone is preferable from the viewpoint of the availability of particles having a suitable refractive index. Resin particles and acrylic resin particles are preferred. Further, particles having a hollow structure can also be used. In addition, as the 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, and have a suitable refractive index. Titanium oxide and aluminum oxide are preferred from the viewpoint of the availability of particles.

  From the viewpoint of the light scattering effect and the brittleness of the wavelength conversion layer containing the particles, the light scattering particles should be included in the wavelength conversion layer in an amount of 0.2% by volume or more based on 100% by volume of the entire wavelength conversion layer. Is preferably contained, more preferably from 0.2 to 50% by volume, even more preferably from 0.2 to 30% by volume, and even more preferably from 0.2 to 10% by volume. .

In order to adjust the refractive index of the portion of the matrix other than 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 adjusting particles is less than 0.10 μm.
Examples of the refractive index adjusting particles include particles of diamond, titanium oxide, zirconium oxide, lead oxide, lead carbonate, zinc oxide, zinc sulfide, antimony oxide, silicon oxide, aluminum oxide, and the like. The refractive index adjusting particles may be used in an amount capable of adjusting the refractive index, and the content in the wavelength conversion layer is not particularly limited.

[Backlight unit]
The wavelength conversion member can be used as a constituent member of the backlight unit. The backlight unit includes at least a wavelength conversion member and a light source.

(Emission wavelength of backlight unit)
From the viewpoint of realizing high luminance and high color reproducibility, it is preferable to use a backlight unit that has a multi-wavelength light source. As a preferred embodiment, a blue light having an emission center wavelength in a wavelength band of 430 to 480 nm, a blue light having an emission intensity peak whose half width is 100 nm or less, and an emission center wavelength in a wavelength band of 500 to 600 nm A green light having an emission intensity peak whose half width is 100 nm or less, and a red light having an emission intensity peak having a light emission center wavelength in a wavelength band of 600 to 680 nm and a half width of 100 nm or less. A backlight unit that emits light can be given.
From the viewpoint of further improving luminance and color reproducibility, the wavelength band of the blue light emitted by the backlight unit is preferably in a range of 440 to 480 nm, and more preferably in a range of 440 to 460 nm.
From the same viewpoint, the wavelength band of the 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.
In addition, 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.

  In addition, from the same viewpoint, the half width of each of the emission intensities of the blue light, green light, and red light emitted by the backlight unit is preferably 80 nm or less, more preferably 50 nm or less, and more preferably 40 nm or less. Is more preferable, and more preferably 30 nm or less. Among these, it is particularly preferable that the half 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, a light source that emits 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 that emits blue light can be used. When a light source that emits blue light is used, the wavelength conversion layer preferably contains at least quantum dots A that emit red light and quantum dots B that emit green light when excited by excitation light. Thus, white light can be realized by the blue light emitted from the light source and transmitted through the wavelength conversion member, and the red light and green light emitted from the wavelength conversion member.

Alternatively, in another aspect, a light source that emits ultraviolet light having an emission center wavelength in a wavelength band of 300 nm to 430 nm, for example, an ultraviolet light emitting diode can be used. In this case, the wavelength conversion layer preferably contains quantum dots C that emit blue light when excited by the excitation light, in addition to the quantum dots A and B. Thereby, white light can be realized by the red light, green light, and blue light emitted from the wavelength conversion member.
In yet another embodiment, the light emitting diode can be replaced by a laser light source.

(Structure of backlight unit)
The configuration of the backlight unit may be an edge light type using a light guide plate, a reflection plate or the like as a constituent member, or a direct type. FIG. 1 illustrates an example of an edge light type backlight unit as one embodiment. As the light guide plate, a known one can be used without any limitation.

  Further, the backlight unit may include a reflection member at a rear portion of the light source. Such a reflecting member is not particularly limited, and a known member can be used. The reflecting member is described in, for example, Japanese Patent No. 3416302, Japanese Patent No. 33363565, Japanese Patent No. 4091978, and Japanese Patent No. 3448626. Are incorporated in the present invention.

  The backlight unit also preferably includes a known diffusion plate, diffusion sheet, prism sheet (for example, BEF series manufactured by Sumitomo 3M Limited), and a light guide. Other members are also described in respective publications such as Japanese Patent No. 3416302, Japanese Patent No. 33363565, Japanese Patent No. 4091978, and Japanese Patent No. 3448626, and the contents of these publications are incorporated in the present invention.

[Liquid crystal display]
A liquid crystal display device according to one embodiment of the present invention may have a structure including 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. Twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA), in-plane switching (IPS), optically compensated bend cell (OCB) And various other modes 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 a configuration of a VA mode liquid crystal display device, a configuration shown in FIG. 2 of JP-A-2008-262161 is given as an example. However, the specific configuration of the liquid crystal display device is not particularly limited, and a known configuration can be employed.

  In one embodiment of the liquid crystal display device, the liquid crystal display device includes a liquid crystal cell in which a liquid crystal layer is sandwiched between substrates provided with electrodes on at least one of the opposing electrodes, and the liquid crystal cell is arranged between two polarizing plates. The liquid crystal display device includes a liquid crystal cell in which 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. Further, if necessary, it has a polarizing plate protective film, an optical compensation member for performing optical compensation, and an accompanying functional layer such as an adhesive layer. In addition to (or instead of) a color filter substrate, a thin-layer transistor substrate, a lens film, a diffusion sheet, a hard coat layer, an antireflection layer, a low reflection layer, an antiglare layer, etc., a forward scattering layer, a primer layer, and an antistatic layer. A surface layer such as an undercoat layer may be disposed.

FIG. 4 is a schematic diagram illustrating an example of a liquid crystal display device according to one embodiment of the present invention. The liquid crystal display device 51 shown in FIG. 4 has the 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 include the polarizing plate protective film 11 on the backlight-side surface of the backlight-side polarizer 12, but preferably includes it.
The backlight-side polarizing plate 14 preferably has a configuration in which the polarizer 12 is sandwiched between two polarizing plate protective films 11 and 13.
In this specification, the polarizer protective film on the side closer to the liquid crystal cell with respect to the polarizer is referred to as the inner polarizer protective film, and the polarizer protective film on the side farther from the liquid crystal cell with respect to the polarizer is referred to as the outer polarizer. It is called a protective film. In the example shown in FIG. 4, the polarizing plate protective film 13 is an inner polarizing plate protective film, and the polarizing plate protective film 11 is an outer 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 the surface of the liquid crystal cell 21 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 polarizing plate protective film, and the polarizing plate protective film 41 is an outer polarizing plate protective film.

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

  The liquid crystal cell, the polarizing plate, the polarizing plate protective film, and the like included in the liquid crystal display device according to one embodiment of the present invention are not particularly limited, and those manufactured by a known method or commercially available products can be used without any limitation. it can. It is also possible to provide a known intermediate layer such as an adhesive layer between the layers.

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

  Hereinafter, the present invention will be described more specifically based on examples. Materials, usage amounts, ratios, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples described below.

[Wavelength conversion members 101 to 116]
(1. Production of barrier film 10A)
A barrier laminate was formed on one side of a polyethylene terephthalate film (PET film, manufactured by Toyobo Co., Ltd., trade name: Cosmoshine A4300, thickness 50 μm) according to the following procedure.
TMPTA (trimethylolpropane triacrylate, manufactured by Daicel Ornex) and a photopolymerization initiator (manufactured by Lamberti, ESACURE KTO46) were prepared, weighed to a mass ratio of 95: 5, and dissolved in methyl ethyl ketone. Thus, a coating solution having a solid content of 15% was obtained. This coating solution was applied on the PET film with a roll-to-roll using a die coater, and passed through a drying zone at 50 ° C. for 3 minutes. Thereafter, the film was irradiated with ultraviolet rays (integrated irradiation amount of about 600 mJ / cm ² ) in a nitrogen atmosphere, cured by UV curing, and wound up. The thickness of the first organic layer formed on the support film (the PET film) was 1 μm.

  Next, an inorganic layer (silicon nitride layer) was formed on the surface of the organic layer using a roll-to-roll CVD apparatus. As source gas, silane gas (flow rate 160 sccm (standard condition at 0 ° C., 1 atm, the same applies hereinafter)), ammonia gas (flow rate 370 sccm), hydrogen gas (flow rate 590 sccm), and nitrogen gas (flow rate 240 sccm) were used. A high-frequency power supply having a frequency of 13.56 MHz was used as a power supply. The film forming pressure was 40 Pa, and the ultimate film thickness was 50 nm.

  Next, a second organic layer having a thickness of 1 μm was formed on the inorganic layer by the same composition and in the same process as the first organic layer. Thus, a barrier film 10A in which the organic layer / inorganic layer / organic layer was laminated on the support film in this order was produced.

(2. Preparation of polymerizable composition containing quantum dots)
The following quantum dot-containing polymerizable composition 1 was prepared, filtered through a polypropylene filter having a pore size of 0.2 μm, dried under reduced pressure for 30 minutes, and used as a coating liquid.

-Quantum dot-containing polymerizable composition 1-
3.0 parts by mass of toluene dispersion of quantum dot 1 (maximum emission: 530 nm) (quantum dot 1: INP530-25 manufactured by NN-labs)
0.3 parts by mass of toluene dispersion liquid of quantum dot 2 (maximum emission: 620 nm) (quantum dot 2: INP620-25 manufactured by NN-labs)
Lauryl methacrylate 85.0 parts by mass Trimethylolpropane triacrylate 15.0 parts by mass Phosphorous triester compound 0.2 parts by mass (ADEKA STAB PEP-36 (manufactured by ADEKA CORPORATION))
1.0 part by mass of photopolymerization initiator (Irgacure 819 (manufactured by BASF))

  The quantum dots used in the above, INP530-25 and INP620-25 manufactured by NN Labs, are quantum dots using InP as the core, ZnS as the shell, and oleylamine as the ligand, and 3% by mass in toluene. It was dispersed in concentration.

(3. Preparation of wavelength conversion layer)
The first barrier film 10A is prepared, and the quantum dot-containing polymerizable composition 1 is applied on the organic layer surface by a die coater while continuously transporting the film at a tension of 1 N / m at 1 m / min. A coating was formed. Next, the first barrier film 10A on which the coating film is formed is wound around a backup roller, and the second barrier film 10A is laminated on the coating film so that the organic layer surface is in contact with the coating film. The film was wound around a backup roller with the coating film sandwiched between the second barrier films 10A, and irradiated with ultraviolet rays while being continuously conveyed.

The diameter of the backup roller was φ300 mm, and the temperature of the backup roller was 50 ° C. The irradiation amount of ultraviolet rays was 2000 mJ / cm ² . In FIG. 3, L1 was 50 mm, L2 was 1 mm, and L3 was 50 mm.

  The coating film was cured by irradiation with ultraviolet rays to form a cured layer (wavelength conversion layer), thereby producing a laminated film (wavelength conversion member 101). The thickness of the cured layer of the laminated film was 50 ± 2 μm. No wrinkles were observed in the laminated film. This manufacturing condition is referred to as manufacturing condition A.

  The wavelength conversion member 102 was prepared in the same manner as the wavelength conversion member 101 except that the kind and amount of the phosphite triester compound were changed as described in Table 1 during the production of the quantum dot-containing polymerizable composition 1. To 112 were produced.

  When producing the quantum dot-containing polymerizable composition 1, the wavelength conversion was performed except that the two compounds described in Table 1 were added in the amounts shown in Table 1 instead of the phosphite triester compound. In the same manner as the member 101, wavelength conversion members 113 to 116 were obtained.

(Evaluation of fresh brightness)
A commercially available tablet terminal (Kindle (registered trademark) Fire HDX 7 manufactured by Amazon) was disassembled, and the backlight unit was taken out. The wavelength conversion members 101 to 116 cut out in a rectangular shape were placed on the light guide plate of the backlight unit taken out, and two prism sheets whose surface unevenness patterns were perpendicular to each other were placed thereon. The luminance of light emitted from the blue light source and transmitted through the wavelength conversion member and the two prism sheets was measured by a luminance meter (SR3, manufactured by TOPCON) placed at a position of 740 mm in a direction perpendicular to the surface of the light guide plate. . The measurement of the luminance was performed at the center of the wavelength conversion member, and the fresh luminance (Y0) was used as the evaluation value.

(Evaluation of brightness after storage at high temperature)
The sample whose fresh luminance was measured was stored at 85 ° C. for 300 hours. The luminance (Y1) at the center of the wavelength conversion member after storage at 85 ° C. was measured in the same manner as the evaluation of the luminance before storage, and the change rate (ΔY) of the following equation was taken as an index of the change in luminance. The results are shown in Table 1.
ΔY = (Y0−Y1) ÷ Y0 × 100

(Evaluation of luminance variation during manufacturing of wavelength conversion member)
In the manufacturing condition A in which the wavelength conversion member 101 was manufactured, manufacturing conditions BD in which only the following process conditions were changed were set. In each of the wavelength conversion members 101 to 116, the brightness of the fresh light when the production conditions were changed to B to D was measured.

(Measurement of half width)
The luminance at 380 nm to 780 nm was measured using a luminance meter (SR3, manufactured by TOPCON) by the method described in the evaluation of the luminance of fresh light, and the half-value width of green light and red light was calculated.

Production condition B: The steps of coating the first barrier film to form a coating film and thereafter laminating with the second barrier film were performed in a nitrogen atmosphere having an oxygen concentration of 200 ppm.
Preparation condition C: The steps of coating on the first barrier film to form a coating film and thereafter laminating with the second barrier film were performed in a nitrogen atmosphere having an oxygen concentration of 200 ppm. Further, the irradiation amount of ultraviolet rays was 900 mJ / cm ² .
Manufacturing condition D: The temperature of the backup roller during irradiation with ultraviolet rays was set to 65 ° C.

The difference between the maximum value and the minimum value of the luminance was calculated among four different production conditions A to D, and the percentage (ΔL) with respect to Y0 under the condition A was used as an index of the luminance variation at the time of manufacturing. The results are shown in Table 1.
ΔL = (maximum luminance value-minimum luminance value among production conditions A to D) ÷ Y0 × 100

  The details of the compounds in Table 1 will be described below. In addition, the addition amount in Table 1 shows the addition amount with respect to 100 mass parts of curable monomers in total by mass part.

PEP-36 (manufactured by ADEKA CORPORATION): bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite HP-10 (manufactured by ADEKA CORPORATION): 2,2′-methylenebis (4 , 6-Di-tert-butylphenyl) -2-ethylhexyl phosphite 2112 (made by Adeka Corporation): Tris (2,4-di-tert-butylphenyl) phosphite PEP-8 (made by Adeka Corporation) : Distearyl pentaerythritol diphosphite Sumilizer GP80 (manufactured by Sumitomo Chemical Co., Ltd.): 6-tert-butyl-4- [3- (2,4,8,10-tetra-tert-butyldibenzo [d, f]] [1,3,2] dioxaphosphepin-6-yloxy) propyl] -o-cresol ADEKA STAB C (manufactured by ADEKA CORPORATION): diphenylmonodecyl phosphite A0-20 (manufactured by ADEKA CORPORATION): 1,3 , 5-to (3,5-ditert-butyl-4-hydroxylbenzyl) isocyanurate Sumilizer GS (manufactured by Sumitomo Chemical Co., Ltd.): triethylene glycol bis [(3-tert-butyl-4-hydroxy-5-methyl) Phenyl) propionate], 2- [1- (2-hydroxy-3,5-di-tert-pentylphenyl) ethyl] -4,6-di-tert-pentylphenyl acrylate A0-412S (manufactured by Adeka Corporation): pentaerythritol Tetra (β-dodecylmercaptopropionate)
LA-77Y (made by Adeka Corporation): bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate

  From the results shown in Table 1, it can be seen that the wavelength conversion member using the phosphite triester of the present invention suppresses a decrease in the emission intensity after storage at high temperatures. Further, among the phosphite triesters, a phosphite triester compound in which two ester portions are connected to each other to form a cyclic structure, or a compound in which at least one of the ester portions is an aromatic group having a tertiary alkyl group. It can be seen that the improvement effect is excellent.

  When producing the quantum dot-containing polymerizable composition, the wavelength conversion member 101 except that the type and amount of the polymerization initiator and the type and amount of the phosphite triester were changed as described in Table 2 below. In the same manner as in the above, wavelength conversion members 117 to 125 were produced.

  As shown in Table 2, when the amount of the polymerization initiator is increased, a decrease in luminance after storage at a high temperature is suppressed. In the wavelength conversion member using Irgacure 819, while the half width of red light increases as the amount of the polymerization initiator increases, ethoxyphenyl (2,4,6-trimethylbenzoyl) phosphine oxide and 2,4,6-trimethyl In the wavelength conversion members 122 and 125 using benzoyl-diphenyl-phosphine oxide, the half width of red light is maintained at 30 nm or less even when the amount of the polymerization initiator is 5 parts by mass. It can be seen that the storage brightness is excellent.

[Wavelength conversion members 201 to 209]
The quantum dot-containing polymerizable composition 2 was prepared by changing the composition of the quantum dot-containing polymerizable composition 1 as follows.
-Quantum dot-containing polymerizable composition 2-
3.2 parts by mass of toluene dispersion of quantum dot 1 (maximum emission: 530 nm) (quantum dot 1: INP530-25 manufactured by NN-labs)
0.3 parts by mass of toluene dispersion liquid of quantum dot 2 (maximum emission: 620 nm) (quantum dot 2: INP620-25 manufactured by NN-labs)
Lauryl methacrylate 85.0 parts by mass 1,9-nonanediol diacrylate 10.0 parts by mass Trimethylolpropane triacrylate 5.0 parts by mass Phosphorous triester compound 0.2 parts by mass (ADEKA STAB PEP-36 (ADEKA CORPORATION) Made)
0.2 parts by mass of photopolymerization initiator (Irgacure 819 (manufactured by BASF))

Each of the quantum dots used in the above, INP530-25 and INP620-25 manufactured by NN Labs, is a quantum dot using InP as a core, ZnS as a shell, and oleylamine as a ligand, and 3% by mass in toluene. It was dispersed in concentration.
The quantum dot-containing polymerizable composition 2 was prepared, filtered through a polypropylene filter having a pore size of 0.2 μm, and then dried under reduced pressure for 30 minutes to be used as a coating solution.

  In preparing the quantum dot-containing polymerizable composition, the quantum dot dispersion and the photopolymerization initiator were kept constant, and the types and amounts of other polymerizable compounds and phosphite triester compounds were as shown in Table 3. Except for the change, wavelength conversion members 201 to 209 were manufactured in the same manner as the wavelength conversion member 101. The same evaluation as the wavelength conversion member 101 was performed. Further, as another evaluation, the following evaluation of the luminance after storage at high humidity was performed.

(Evaluation of luminance after storage at high humidity)
The sample for which the fresh luminance was measured was stored at 60 ° C./90% relative humidity for 300 hours. The luminance (Y2) of the central part of the wavelength conversion member after storage was measured by the same method as the evaluation of the luminance before storage, and the change rate (ΔY) of the following equation was used as an index of the luminance change.
ΔY = (Y0−Y2) ÷ Y0 × 100
The results are shown in Table 3.

The details of the compounds in Table 3 will be described below.
LMA: lauryl methacrylate NDA: 1,9-nonanediol diacrylate TMPTA: trimethylolpropane triacrylate OXE-10: (3-ethyloxetane-3-yl) methyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.)
M-100: 3,4-epoxycyclohexylmethyl methacrylate (alicyclic epoxy compound B exemplified in the text)

  From the results shown in Table 3, it can be seen that the wavelength conversion member using the phosphite triester of the present invention suppresses a decrease in emission intensity after storage at high temperatures. In addition, it can be seen that by using a compound having a ring-opening polymerizable epoxy group or oxetane group in combination, the effect is further remarkable, and a decrease in luminescence intensity especially after storage at high humidity is suppressed.

Reference Signs List 1 backlight unit 1A light source 1B light guide plate 1C wavelength conversion member 100 manufacturing device 10 first film 11, 13, 41, 43 polarizing plate protective film 12, 42 polarizer 14 backlight side polarizing plate 20 coating unit 21 liquid crystal cell 22 Coating film 24 Die coater 26 Backup roller 28 Wavelength conversion layer (cured layer)
Reference Signs List 30 laminating section 32 laminating roller 34 heating chamber 44 display-side polarizing plate 50 second film 60 curing section 62 backup roller 64 ultraviolet irradiation device 70 laminated film 80 peeling roller

Claims (20)

A wavelength conversion member having a wavelength conversion layer including a quantum dot that emits fluorescence when excited by excitation light,
The wavelength conversion layer includes an organic matrix,
The organic matrix is a monofunctional (meth) acrylate monomer and a polyfunctional (meth) acrylate monomer (excluding the monofunctional (meth) acrylate monomer having an aliphatic polycyclic substituent.) And (meth) acrylic Lilo yl A wavelength conversion member comprising a polymer of a polyfunctional (meth) acrylate monomer having two or more groups in one molecule and a phosphite triester.   2. The wavelength conversion member according to claim 1, wherein the phosphite triester is a phosphite triester compound in which two ester portions are connected to each other and has a cyclic structure. 3.   The wavelength conversion member according to claim 1 or 2, wherein the phosphite triester is a phosphite triester compound in which at least one of the ester portions contains an aromatic group having a tertiary alkyl group.   4. The wavelength conversion member according to claim 1, wherein the phosphite triester is a phosphite triester compound having a softening point or a melting point of 40 ° C. or more and 300 ° C. or less. 5.   The wavelength conversion member according to any one of claims 1 to 4, wherein the organic matrix further contains a compound having a ring-opening polymerizable group or a polymer of the compound.   The wavelength conversion member according to any one of claims 1 to 5, wherein the wavelength conversion layer includes at least one type of photopolymerization initiator, and the photopolymerization initiator is a monoacylphosphine oxide-based compound.   The wavelength conversion member according to any one of claims 1 to 6, including a base material, wherein at least one surface of the wavelength conversion layer is in direct contact with the base material.   The wavelength conversion member according to claim 7, wherein the wavelength conversion member includes two of the base materials, each of the base films being a barrier film including an inorganic layer, and including the wavelength conversion layer between the two barrier films. The barrier oxygen permeability of the film, the wavelength converting member according to claim 8 either at ^{1cm 3 / (m 2 · day} · atm) or less.   The said quantum dot contains the 1st quantum dot which has a luminescence center wavelength in 500 nm-600 nm, and the 2nd quantum dot which has a luminescence center wavelength in 600-680 nm. 2. The wavelength conversion member according to 1.   A backlight unit including at least the wavelength conversion member according to any one of claims 1 to 10 and a light source.   The backlight unit according to claim 11, wherein the light source is a blue light emitting diode or an ultraviolet light emitting diode.   13. The backlight unit according to claim 11, further comprising a light guide plate, wherein the wavelength conversion member is arranged on a path of light emitted from the light guide plate.   13. The backlight unit according to claim 11, further comprising a light guide plate, wherein the wavelength conversion member is disposed between the light guide plate and the light source.   A liquid crystal display device comprising at least the backlight unit according to claim 11 and a liquid crystal cell. Is excited by the excitation light (except where the monofunctional (meth) acrylate monomer having an aliphatic polycyclic substituent.) And quantum dots emit fluorescence, monofunctional (meth) acrylate monomers and (meth) acrylic Lilo A quantum dot-containing polymerizable composition comprising: a radical polymerizable compound containing a polyfunctional (meth) acrylate monomer having two or more yl groups in one molecule; and a phosphite triester.   17. The quantum dot-containing polymerizable composition according to claim 16, further comprising a ring-opening polymerizable compound.   18. The quantum dot-containing polymerizable composition according to claim 17, wherein the ring-opening polymerizable compound is a compound having an epoxy group.   The quantum dot-containing polymerizable composition according to claim 17 or 18, wherein the content of the ring-opening polymerizable compound is 0.05% by mass or more and 10.0% by mass or less based on all polymerizable compounds.   The quantum dot according to any one of claims 16 to 19, wherein the quantum dot-containing polymerizable composition contains at least one photopolymerization initiator, and the photopolymerization initiator is a monoacylphosphine oxide-based compound. Dot-containing polymerizable composition.