Quantum dots, quantum dot-containing sheet and method for manufacturing same, and backlight device or display device

Abstract

The purpose of the present invention is to provide: quantum dots that make it possible to attain a sheet that is capable of having a quantum dot layer thickness of 50 μm or less and demonstrates excellent durability starting at the edges of the sheet over time; a quantum dot-containing sheet using said quantum dots; and a backlight device or a display device. The quantum dots of the present invention are characterized by containing no RoHS restricted substances and having a higher absorption coefficient at 450 nm than InP. In the present invention, the quantum dots preferably include a core formed from a I-III-VI chalcopyrite system. It is preferable that group I contains at least one of Ag and Cu, group III contains at least one of Ga and In, and group VI contains at least one of S, Se, and Te. A quantum dot-containing sheet obtained by curing a quantum dot-containing composition containing the quantum dots of the present invention is characterized by having a quantum dot layer thickness of 50 μm or less. The length of deterioration starting from the edges of the sheet is preferably 500 μm or shorter.

Description

Quantum dots, quantum dot-containing sheet and manufacturing method thereof, and backlight device or display device

[0001] The present invention relates to quantum dots, a quantum dot-containing sheet and a method for producing the same, and a backlight device or a display device.

[0002] Suppressing deterioration from the edges of a sheet containing quantum dots is thought to depend largely on the structure of the quantum dots and the resin in which the quantum dots are dispersed. The following patent documents aim to improve durability by focusing on the resin used in the resin composition containing quantum dots and the structure of the laminated form. However, they do not specifically disclose quantum dots that can suppress deterioration from the edges of the sheet while reducing the layer thickness of the sheet.

[0003] Japanese Patent Publication No. 2016-511709 Japanese Patent No. 5940079 International Publication No. 2018 / 056469 Korean Patent No. 10-1969561 Japanese Patent Publication No. 2017-032918 Japanese Patent Publication No. 2019-086555 Japanese Patent Publication No. 2018-124412 Japanese Patent Publication No. 2017-214486

[0004] The present invention has been made in consideration of the above-mentioned current situation, and aims to provide quantum dots that enable the quantum dot layer thickness to be 50 μm or less and that make it possible to obtain a sheet with excellent durability over time from the sheet edge, as well as a quantum dot-containing sheet using the same, a method for manufacturing the same, and a backlight device or a display device.

[0005] The quantum dots of the present invention are characterized by not containing any RoHS restricted substances and having a higher absorption coefficient at 450 nm than InP.

[0006] By using the quantum dots of the present invention, the thickness of the quantum dot layer can be reduced to 50 μm or less, and a sheet having excellent durability over time from the sheet edge can be obtained.

[0007] 11B is a schematic diagram of quantum dots. FIG. 11C is a longitudinal sectional view of a quantum dot-containing sheet showing a first embodiment of the present invention. FIG. 11D is a longitudinal sectional view of a quantum dot-containing sheet showing a second embodiment of the present invention. FIG. 11E is a longitudinal sectional view of a quantum dot-containing sheet showing a third embodiment of the present invention. FIG. 11F is a perspective view of a quantum dot-containing sheet of the present embodiment. FIG. 11G is a longitudinal sectional view of a display device using the quantum dot-containing sheet of the present embodiment. FIG. 11H is a longitudinal sectional view of a display device different from that shown in FIG. 6, using the quantum dot-containing sheet of the present embodiment. FIG. 11I is a longitudinal sectional view of a liquid crystal display element using the quantum dot-containing sheet of the present embodiment. FIG. 11I is a cross-sectional view showing an example of the quantum dot-containing sheet of the present embodiment. FIG. 11I is a cross-sectional view showing an example of the production of the quantum dot-containing sheet of the present embodiment. FIG. 11I is a cross-sectional view of a quantum dot-containing sheet provided with base films on both sides of a quantum dot layer. FIG. 11I is a cross-sectional view of a quantum dot-containing sheet provided with a base film only on one side of the quantum dot layer by peeling off one of the base films shown in FIG. 11A. FIG. 11I is a conceptual diagram showing a production apparatus for producing a quantum dot-containing sheet of the present embodiment. FIG. 11I is a graph showing the relationship between wavelength and absorption coefficient for chalcopyrite quantum dots of an example and InP of a comparative example. 1 is a graph showing the relationship between wavelength and absorption coefficient for chalcopyrite quantum dots of an example and InP of a comparative example. The upper row is EDX mapping of Ag and Ga, and the lower row is a schematic diagram of a portion thereof. The upper row is EDX mapping of Zn and S, and the lower row is a schematic diagram of a portion thereof. This is a graph showing the relationship between wavelength (400 nm to 700 nm) and luminance, obtained using a quantum dot-containing direct-type optical element equipped with a partial reflection sheet and a quantum dot-containing direct-type optical element not equipped with a partial reflection sheet. This is a graph showing the relationship between wavelength (400 nm to 700 nm) and luminance, obtained using a quantum dot-containing direct-type optical element (with DBEF) equipped with a partial reflection sheet and a quantum dot-containing direct-type optical element (with DBEF) not equipped with a partial reflection sheet. 10 is a graph showing the relationship between wavelength (500 nm to 700 nm) and brightness when using a quantum dot-containing direct-type optical element with a partially reflective sheet and a quantum dot-containing direct-type optical element without a partially reflective sheet.1 is a graph showing the relationship between wavelength (500 nm to 700 nm) and luminance when using a quantum dot-containing direct-type optical element (with DBEF) equipped with a partial reflection sheet and a quantum dot-containing direct-type optical element (with DBEF) without a partial reflection sheet. 2 is a graph showing the relationship between wavelength (400 nm to 700 nm) and luminance when using a quantum dot-containing direct-type optical element equipped with a partial reflection sheet and a quantum dot-containing direct-type optical element without a partial reflection sheet. 3 is a graph showing the relationship between wavelength (400 nm to 700 nm) and luminance when using a quantum dot-containing direct-type optical element equipped with a partial reflection sheet and a quantum dot-containing direct-type optical element without a partial reflection sheet. 4 is a graph showing the relationship between wavelength (500 nm to 700 nm) and luminance when using a quantum dot-containing direct-type optical element equipped with a partial reflection sheet and a quantum dot-containing direct-type optical element without a partial reflection sheet. 1 is a graph showing the relationship between wavelength (500 nm to 700 nm) and brightness, obtained by using a quantum dot-containing direct-type optical element equipped with a partially reflective sheet and a quantum dot-containing direct-type optical element without a partially reflective sheet. FIG. 1 is a schematic diagram of Sample 7. FIG. 1 is a schematic diagram of Sample 8. FIG. 1 is a schematic diagram of Sample 9. FIG. 10 is a schematic diagram of Sample 11. FIG. 12 is a schematic diagram of Sample 13. FIG. 14 is a backlight emission spectrum. FIG. 15 is an emission spectrum of Example 1. FIG. 16 is an emission spectrum of Example 2. FIG. 17 is a photograph and a schematic diagram showing a degradation mode of this example. FIG. 18 is a schematic diagram showing an application example of the quantum dot-containing sheet of this example.

[0008] The following describes in detail an embodiment of the present invention, but the following description is an example (typical example) of the embodiment of the present description, and the present invention is not limited to these details as long as it does not deviate from the gist of the present invention. Furthermore, the notation "to" used below includes both the lower limit and the upper limit within the range.

[0009] <Quantum Dots> The quantum dots used in this embodiment are nanoparticles with a particle size of about several nm to several tens of nm, and are materials that absorb excitation light and emit light efficiently. The peak wavelength of emission can be controlled by the composition and particle size of the nanoparticles, and quantum dots that emit red and green light are preferably used for display material applications. In some cases, quantum dots that emit blue light may also be used, and quantum dots with a suitable wavelength can be used in this embodiment as well.

[0010] The quantum dots of this embodiment are characterized by not containing any RoHS-regulated substances and having a higher absorption coefficient at 450 nm than InP. As such, the quantum dots do not contain any RoHS-regulated substances such as cadmium or lead as elements contained therein. Furthermore, the quantum dots of this embodiment have a higher absorption coefficient at 450 nm than InP, which is a commercially available cadmium-free quantum dot.

[0011] The quantum dots of this embodiment have a core made of a I-III-VI type chalcopyrite system. That is, the core is an Ag—Ga—S2 system, and the Group I element may be Cu instead of Ag, or may contain both Ag and Cu.

[0012] Furthermore, the group III element may be In instead of Ga, or may contain both Ga and In.

[0013] Furthermore, the Group VI element may be Se or Te instead of S, or may contain S and Se, S and Te, Se and Te, or S, Se and Te.

[0014] In this embodiment, for example, the quantum dots are AgIn ｘ Ga １－ｘ S ｙ Se １－ｙ system, or ZnAgIn ｘ Ga １－ｘ S ｙ Se １－ｙThe quantum dots are nanocrystals containing at least silver (Ag), gallium (Ga), and sulfur (S), or silver (Ag), gallium (Ga), and selenium (Se), and are preferably nanocrystals containing no cadmium (Cd). The quantum dots may also contain Ag, Ga, and S, or Ag, Ga, and Se, and may further contain indium (In) or zinc (Zn).

[0015] Here, the term "nanocrystal" refers to nanoparticles having a particle size of about several nanometers to several tens of nanometers. In this embodiment, a large number of quantum dots can be produced with a substantially uniform particle size.

[0016] The ratio of Ag to Ga contained in the quantum dots, Ag / Ga, is preferably in the range of 0.05 to 10. The ratio Ag / Ga is more preferably in the range of 0.05 to 5, and even more preferably in the range of 0.1 to 3.

[0017] The ratio of Zn to Ga that can be contained in the quantum dots is preferably in the range of Zn / Ga = 0.1 or more and 10 or less. The ratio Zn / Ga is more preferably in the range of 0.1 or more and 5 or less. By controlling this ratio, it is possible to adjust the emission wavelength. In this embodiment, the fluorescence wavelength can be adjusted from the green wavelength region to the red wavelength region. In particular, in this embodiment, the fluorescence wavelength can be appropriately adjusted within the range of 400 nm or more and 700 nm or less. In this embodiment, the fluorescence wavelength can also be adjusted within the range of 500 nm or more and 650 nm or less.

[0018] In the quantum dot of this embodiment, a shell layer is formed on the surface of the core via a buffer layer. The buffer layer is a region in which at least some or all of the elements constituting the core and at least some or all of the elements constituting the shell layer are mixed. The shell layer is preferably made of ZnS. It is also preferable that the surface of the shell layer is provided with a ligand.

[0019] Fig. 1 is a schematic diagram of a quantum dot. As shown in Fig. 1, the quantum dot 5 comprises a core 5a, a shell layer 5b formed on the surface of the core 5a, and organic ligands 6 disposed on the surface of the shell layer 5b. In order to suppress aggregation of the quantum dots 5 and obtain excellent optical properties, it is preferable that a large number of organic ligands 6 are coordinated on the surface of the quantum dot 5.

[0020] The ligand used in this embodiment is not limited to the following, but for example, oleylamine: C １８ H ３５ NH ２ , stearyl(octadecyl)amine: C １８ H ３７ NH ２ , dodecyl(lauryl)amine: C １２ H ２５ NH ２ , decylamine: C １０ H ２１ NH ２ , octylamine: C ８ H １７ NH ２ aliphatic amine compounds such as:

[0021] Fatty acids, oleic acid: C １７ H ３３ COOH, stearic acid: C １７ H ３５ COOH, palmitic acid: C １５ H ３１ COOH, myristic acid: C １３ H ２７ COOH, lauryl (dodecanoic) acid: C １１ H ２３ COOH, decanoic acid: C ９ H １９ COOH, octanoic acid: C ７ H １５ fatty acid compounds such as COOH;

[0022] Octadecanethiol: C １８ H ３７ SH, hexanedecanethiol: C １６ H ３３ SH, tetradecanethiol: C １４ H ２９ SH, dodecanethiol: C１２ H ２５ SH, decanethiol: C １０ H ２１ SH, octanethiol: C ８ H １７ Thiol compounds such as SH; trioctylphosphine: (C ８ H １７ ) ３ P, triphenylphosphine: (C ６ H ５ ) ３ P, tributylphosphine: (C ４ H ９ ) ３ P

[0023] Phosphine oxide series, trioctylphosphine oxide: (C ８ H １７ ) ３ P═O, triphenylphosphine oxide: (C ６ H ５ ) ３ P═O, tributylphosphine oxide: (C ４ H ９ ) ３ These may be used alone or in any combination of two or more.

[0024] Although not shown in Fig. 1, a buffer layer is formed between the core 5a and the shell layer 5b. The shell layer 5b is preferably made of ZnS, but may be made of ZnSe instead.

[0025] In this embodiment, the structure is a core / buffer layer (a mixed layer of core and shell layers) / shell layer. The buffer layer is, for example, AgGaS ２ , (AgZnGa)S ２ , AgGaSe ２ , (AgZnGa)Se ２ In Fig. 1, the boundary between the core 5a and the shell layer 5b is shown by a dotted line, but this means that the boundary between the core 5a and the shell layer 5b does not necessarily have to be clearly confirmed by analysis. Although not shown in the drawing, a buffer layer is interposed in the dotted line portion.

[0026] The quantum dots used in this embodiment are preferably quantum dots that emit green light with a peak wavelength of 520 to 560 nm (hereinafter referred to as green quantum dots) and quantum dots that emit red light with a peak wavelength of 600 to 680 nm (hereinafter referred to as red quantum dots). The quantum dots of this embodiment absorb blue light of 450 nm and have a higher absorption coefficient than InP.

[0027] In this embodiment, quantum dots having a fluorescence full width at half maximum (FWHM) of 40 nm or less, preferably 35 nm or less, and more preferably 30 nm or less are suitably used.

[0028] The amount of quantum dots contained in the quantum dot-containing composition described below is preferably in the range of 0.03% by mass to 2% by mass, more preferably 0.05% by mass to 1% by mass, relative to 100% by mass of the sum of the polyfunctional (meth)acrylate and the polyfunctional thiol. Thus, when the amount of quantum dots is in the range of 0.03 to 2% by mass, sufficient luminescence intensity derived from the quantum dots can be obtained.

[0029] <Quantum Dot-Containing Composition> In this embodiment, a quantum dot-containing composition containing the quantum dots described above is produced. In addition to the quantum dots, the composition contains a polyfunctional (meth)acrylate, a polyfunctional thiol, and a reaction retarder.

[0030] In this embodiment, by adjusting the composition of the quantum dots, the core-shell structure, and the ligands, and optimizing the dispersion resin, it is possible to realize a thin sheet and effectively suppress deterioration of the sheet edge. Below, each substance contained in the quantum dot-containing composition will be described.

[0031] (Polyfunctional (meth)acrylate) A polyfunctional (meth)acrylate has two or more (meth)acrylate groups in one molecule. In this embodiment, a cured coating can be obtained by radically polymerizing a polyfunctional (meth)acrylate and a polyfunctional thiol described below using a photopolymerization initiator described below. This cured film can dramatically improve the durability of the quantum dots of this embodiment. In addition, when producing a quantum dot-containing sheet, it also functions as an adhesive for bonding two plastic films together.

[0032] The polyfunctional monomer used in the present embodiment is not limited to the following, but examples thereof include 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, tetrapropylene glycol diacrylate, polypropylene glycol diacrylate, neopentyl glycol diacrylate, neopentyl glycol PO-modified diacrylate, hydroxypivalic acid neopentyl glycol ester diacrylate, caprolactone adduct diacrylate of hydroxypivalic acid neopentyl glycol ester, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, tetrapropylene glycol diacrylate, polypropylene glycol diacrylate, neopentyl glycol diacrylate, hydroxypivalic acid neopentyl glycol ester ... bifunctional acrylate monomers such as ,6-hexanediol bis(2-hydroxy-3-acryloyloxypropyl)ether, bis(4-acryloxypolyethoxyphenyl)propane, 1,9-nonanediol diacrylate, pentaerythritol diacrylate, pentaerythritol diacrylate monostearate, pentaerythritol diacrylate monobenzoate, bisphenol A diacrylate, EO-modified bisphenol A diacrylate, PO-modified bisphenol A diacrylate, bisphenol F diacrylate, EO-modified bisphenol F diacrylate, PO-modified bisphenol F diacrylate, EO-modified tetrabromobisphenol A diacrylate, tricyclodecane dimethylol diacrylate, isocyanuric acid EO-modified diacrylate, and 2-hydroxy-1,3-diacryloxypropane; trifunctional acrylate monomers such as glycerin PO-modified triacrylate, trimethylolpropane triacrylate, trimethylolpropane EO-modified triacrylate, trimethylolpropane PO-modified triacrylate, isocyanuric acid EO-modified triacrylate, isocyanic acid EO-modified ε-caprolactone-modified triacrylate, 1,3,5-triacryloylhexahydro-s-triazine, pentaerythritol triacrylate, and dipentaerythritol triacrylate tripropionate;Examples of the acrylate monomer include tetrafunctional or higher acrylate monomers such as pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate monopropionate, dipentaerythritol hexaacrylate, tetramethylolmethane tetraacrylate, oligoester tetraacrylate, and tris(acryloyloxy)phosphate. These may be used alone or in any combination of two or more.

[0033] The average number of functional groups per molecule of the polyfunctional (meth)acrylate used in the present embodiment is preferably 2 or more, more preferably 2.5 or more, and even more preferably 3 or more. When the number of functional groups is 2 or more, a sufficient degree of crosslinking can be obtained as a cured film, and excellent durability can be obtained.

[0034] (Polyfunctional Thiol) The polyfunctional thiol used in the present embodiment has two or more mercapto groups in one molecule. The polyfunctional thiol is used to impart excellent oxygen barrier properties to a cured film when combined with a polyfunctional (meth)acrylate.

[0035] The polyfunctional thiol used in the present embodiment is not limited to the following, but examples thereof include ethylene glycol bis(3-mercaptopropionate), diethylene glycol bis(3-mercaptopropionate), tetraethylene glycol bis(3-mercaptopropionate), 1,2-propylene glycol bis(3-mercaptopropionate), diethylene glycol bis(3-mercaptobutyrate), 1,4-butanediol bis(3-mercaptopropionate), 1,4-butanediol bis(3-mercaptobutyrate), 1,8-octanediol bis(3-mercaptopropionate), 1,8-octanediol bis(3-mercaptobutyrate), hexanediol bisthioglycolate, trimethylolpropane tris(3-mercaptopropionate), trimethylolpropane tris(3-mercaptobutyrate), trimethylolpropane tris(3-mercaptobutyrate), and hexanediol bisthioglycolate. trimethylolpropane tris(3-mercaptobutyrate), trimethylolpropane tristhioglycolate, tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolethane tris(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis Examples thereof include tetrakis(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptoisobutyrate), dipentaerythritol hexakis(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptobutyrate), dipentaerythritol hexakis(3-mercaptoisobutyrate), pentaerythritol tetrakisthioglycolate, dipentaerythritol hexakis-cisthioglycolate, etc. These may be used alone or in any combination of two or more.

[0036] The average number of functional groups per molecule of the polyfunctional thiol used in the present embodiment is preferably 2 or more, more preferably 2.5 or more, and even more preferably 3 or more. When the number of functional groups is 2 or more, a sufficient degree of crosslinking can be obtained as a cured film, and excellent durability can be obtained.

[0037] The ratio of the number of moles of (meth)acrylate groups in the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups in the polyfunctional thiol used in this embodiment (number of moles of acrylate groups / number of moles of mercapto groups) is preferably in the range of 0.6 to 9.0, more preferably in the range of 0.8 to 5.5, and even more preferably in the range of 1.0 to 2.5. When the molar ratio of mercapto groups to (meth)acrylate groups is in the range of 0.6 to 9.0, preferably in the range of 0.8 to 5.5, a film with high crosslink density is formed after the curing reaction, and excellent durability is obtained. Alternatively, the ratio of the number of moles of (meth)acrylate groups in the polyfunctional (meth)acrylate to the number of moles of mercapto groups in the polyfunctional thiol used in this embodiment (number of moles of acrylate groups / number of moles of mercapto groups) is preferably in the range of 1.52 to 9.0.

[0038] (Reaction retarder) The reaction retarder used in the present embodiment is added to delay the reaction between the (meth)acrylate group and the mercapto group when the polyfunctional (meth)acrylate and the polyfunctional thiol are mixed, thereby obtaining an excellent pot life.

[0039] Examples of the reaction retarder used in this embodiment include, but are not limited to, phenolic compounds, phosphorous compounds, dithiocarbamate compounds, and the like. Among these, it is preferable to select at least one of phosphorous compounds and dithiocarbamate compounds, from the viewpoint that an excellent pot life can be obtained with a small amount of compounding. Examples of phenolic compounds include, but are not limited to, 4-methoxyphenol and hydroquinone. Examples of phosphorous compounds include, but are not limited to, dimethyl phosphite, diethyl phosphite, dibutyl phosphite, diisopropyl phosphite, diisobutyl phosphite, diphenyl phosphite, dibenzyl phosphite, bis(2,2,2-trifluoroethyl) phosphite, trimethyl phosphite, triethyl phosphite, triisopropyl phosphite, tributyl phosphite, trihexyl phosphite, triethylhexyl phosphite, trioctyl phosphite, triisodecyl phosphite, trilauryl phosphite, triphenyl phosphite, and tri-o-tolyl phosphite. Examples of dithiocarbamate compounds include, but are not limited to, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetraisopropylthiuram disulfide, tetrabutylthiuram disulfide, tetramethylthiuram monosulfide, and dipentamethylenethiuram tetrasulfide. These compounds may be used alone or in any combination of two or more. In this embodiment, it is more preferable to use a dithiocarbamate compound as the reaction retarder.

[0040] The amount of the reaction retarder used in this embodiment is preferably in the range of 0.0005% by mass to 1% by mass, more preferably 0.0005% by mass to 0.5% by mass, relative to 100% by mass of the sum of the polyfunctional (meth)acrylate and the polyfunctional thiol. When the amount is 0.0005% by mass or more, a sufficient reaction retardation effect is obtained, resulting in a good pot life. Furthermore, when the amount is 0.5% by mass or less, curing inhibition during the curing reaction during the production of the quantum dot-containing sheet can be suppressed, resulting in excellent durability.

[0041] (Scattering Agent) In this embodiment, a scattering agent can be further included. The scattering agent used in this embodiment can scatter the excitation light of the quantum dots, thereby extending the optical path length and efficiently increasing the emission intensity of the quantum dots.

[0042] Examples of scattering agents used in this embodiment include organic scattering agents, inorganic scattering agents, and organic-inorganic hybrid scattering agents. Examples of organic scattering agents used in this embodiment include, but are not limited to, resin fine particles such as polystyrene-based fine particles, polymethyl methacrylate-based fine particles, polyurethane-based fine particles, polyethylene-based fine particles, polypropylene-based fine particles, melamine-based fine particles, and benzoguanamine-based fine particles. These may be used alone, or two or more types may be used in any combination. Furthermore, these are generally obtained by heterogeneous polymerization such as suspension polymerization, and may be internally crosslinked or have functional groups such as acrylate groups on the surface.

[0043] Examples of inorganic scattering agents used in the present embodiment include, but are not limited to, silica particles such as colloidal silica, fumed silica, and precipitated silica, inorganic oxides such as alumina particles, zirconia particles, titania particles, and zinc oxide particles, talc, mica, kaolin, and clay. These may be used alone or in any combination of two or more. Furthermore, these may be surface-treated with a silane coupling agent or the like.

[0044] The organic-inorganic hybrid used in the present embodiment includes, but is not limited to, silica-containing resin particles, titania-containing resin particles, silica-modified resin particles, etc. These may be used alone or in any combination of two or more.

[0045] The scattering agent used in this embodiment is preferably fine particles having at least one of a melamine structure and a benzoguanamine structure, from the viewpoint that the scattering efficiency is high due to the high refractive index and the quantum yield is high due to the high transparency.

[0046] The amount of the scattering agent used in this embodiment is preferably in the range of 0.05% by mass or more and 10% by mass or less, and more preferably in the range of 0.1% by mass or more and 8% by mass or less, relative to 100% by mass of the sum of the polyfunctional (meth)acrylate (A) and the polyfunctional thiol.

[0047] (Photopolymerization initiator) In this embodiment, it is preferable to further include a photopolymerization initiator. The photopolymerization initiator used in this embodiment is used to efficiently promote the curing reaction due to crosslinking of the polyfunctional (meth)acrylate and the polyfunctional thiol. During the curing reaction, it is preferable to use active energy rays such as ultraviolet rays or electron beams, and more preferably ultraviolet rays. The wavelength and irradiation amount of the active energy rays can be appropriately set, and for example, ultraviolet rays with a wavelength of 280 to 400 nm can be used at 100 mJ / cm. ２ ~5000mJ / cm ２ Examples of light sources for generating ultraviolet light include known light sources such as low-pressure mercury lamps, high-pressure mercury lamps, metal halide lamps, and xenon lamps. These may be used alone or in any combination of two or more.

[0048] As the photopolymerization initiator used in the present embodiment, known photopolymerization initiators can be used, for example, acetophenones such as diethoxyacetophenone, 2-hydroxy-1-phenylpropan-1-one, benzyl methyl ketal, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butane, oligo{2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone}, 2-hydroxy-1-{4-(2-hydroxy-2-methylpropionyl)benzyl}phenyl}-2-methylpropan-1-one; benzoins such as benzoin methyl ether and benzoin ethyl ether; Examples of the phosphines include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; and phenyl glyoxylic methyl ester. These may be used alone or in any combination of two or more.

[0049] The amount of the photopolymerization initiator used in this embodiment is preferably in the range of 0.05% by mass or more and 5% by mass or less, and more preferably 0.1% by mass or more and 4% by mass or less, relative to 100% by mass of the sum of the polyfunctional (meth)acrylate and the polyfunctional thiol.

[0050] In this embodiment, a photosensitizer can be used in combination with the photopolymerization initiator in order to further enhance curability. Known photosensitizers can be used as the photosensitizer, and examples thereof include unsaturated ketones such as chalcone derivatives and dibenzalacetone, 1,2-diketones such as benzil and camphorquinone, polymethine dyes such as benzoin derivatives, fluorene derivatives, naphthoquinone derivatives, anthraquinone derivatives, xanthene derivatives, thioxanthene derivatives, xanthone derivatives, thioxanthone derivatives, coumarin derivatives, ketocoumarin derivatives, cyanine derivatives, merocyanine derivatives, and oxonol derivatives, acridine derivatives, azine derivatives, thiazine derivatives, oxazine derivatives, and indoline. derivatives, azulene derivatives, azulenium derivatives, squarylium derivatives, porphyrin derivatives, tetrapyrazinoporphyrazine derivatives, phthalocyanine derivatives, tetraazaporphyrazine derivatives, tetraquinoxalylporphyrazine derivatives, naphthalocyanine derivatives, subphthalocyanine derivatives, pyrylium derivatives, thiopyrylium derivatives, tetraphylline derivatives, annulene derivatives, spiropyran derivatives, spirooxazine derivatives, thiospiropyran derivatives, metal arene complexes, organic ruthenium complexes, Michler's ketone derivatives, biimidazole derivatives, etc. These may be used alone or in any combination of two or more.

[0051] The amount of the photosensitizer used in this embodiment is preferably in the range of 0.05% by mass or more and 5% by weight or less, relative to 100% by mass of the sum of the polyfunctional (meth)acrylate and the polyfunctional thiol.

[0052] (Dispersion Resin) In this embodiment, it is preferable to further include a dispersion resin. The dispersion resin used in this embodiment is used for the purpose of improving the compatibility of the quantum dots and scattering agent with the polyfunctional (meth)acrylate and polyfunctional thiol. By improving the compatibility, it is possible to suppress the in-plane variation in the brightness of the cured film made of the quantum dot-containing composition, and also to suppress the decrease in luminescence quantum yield due to aggregation of the quantum dots.

[0053] The dispersing resin used in the present embodiment is not limited to the following, but examples thereof include acrylic resins, polyurethane resins, polyester resins, polyolefin resins, polycarbonate resins, polyethyleneimine resins, epoxy resins, thioether resins, etc. In particular, from the viewpoint of excellent compatibility with polyfunctional (meth)acrylates and polyfunctional thiols, at least one resin selected from acrylic resins, polyurethane resins, polyester resins, and polyethyleneimine resins is preferred.

[0054] The acrylic resin used in this embodiment is obtained by polymerizing a monomer having an unsaturated group such as a (meth)acrylate group, a vinyl group, or an allyl group by a known polymerization method such as radical polymerization, living radical polymerization, anionic polymerization, cationic polymerization, etc. The urethane resin used in this embodiment is obtained by subjecting a polyol and a polyisocyanate to a urethanization reaction using a known method.

[0055] The polyester resin used in the present embodiment can be obtained by esterifying a polybasic acid and a polyol using a known method, or by ring-opening polymerization of a cyclic ester compound such as caprolactone or butyrolactone using a known method.

[0056] Polyolefin resins are obtained by polymerizing olefin monomers such as ethylene, propylene, butene, and isobutene using known polymerization methods such as coordination polymerization, etc. Polycarbonate resins are obtained by carbonation reaction of polyols and polyfunctional carbonates such as diethyl carbonate using known methods.

[0057] Polyethyleneimine resins can be obtained by ring-opening polymerization of an aziridine compound. Polyethyleneimine resins grafted with polyester resins can also be used, which are obtained by reacting a cyclic ester compound with the amino group generated after the reaction and then ring-opening polymerization. Epoxy resins can be obtained by ring-opening polymerization of a compound having two or more glycidyl groups using a known method.

[0058] Furthermore, from the viewpoint of effectively obtaining excellent compatibility by adsorbing to the quantum dots and the scattering agent, the dispersing resin preferably has a polar functional group such as a carboxyl group, a sulfonic acid group, a phosphate group, an amino group, a mercapto group, or a hydroxyl group, and more preferably a phosphate group, an amino group, or a mercapto group. These are preferred not only because they can obtain excellent compatibility but also because they can increase the luminescence quantum yield of the quantum dots.

[0059] The blending amount of the dispersion resin used in this embodiment is preferably in the range of 0.1% by mass or more and 5% by mass or less, and more preferably in the range of 0.2% by mass or more and 4% by mass or less, relative to 100% by mass of the sum of the polyfunctional (meth)acrylate and the polyfunctional thiol.

[0060] In this embodiment, a known organic solvent may be used as a dilution solvent for the quantum dots, as a reaction solvent during synthesis of the dispersion resin, or for the purpose of adjusting the viscosity during application of the quantum dot-containing composition. Note that the known organic solvent is preferably removed during the curing process described below.

[0061] Examples of solvents used in the present embodiment include, but are not limited to, ester-based solvents such as ethyl acetate, propyl acetate, and butyl acetate, ketone-based solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, ether-based solvents such as dioxane and tetrahydrofuran, aliphatic hydrocarbon-based solvents such as n-hexane, cyclohexane, and methylcyclohexane, aromatic hydrocarbon-based solvents such as toluene and xylene, alcohol-based solvents such as methanol, ethanol, and isopropanol, amide-based solvents such as dimethylformamide, and water. These solvents may be used alone or in any combination of two or more.

[0062] The quantum dot-containing composition of the present embodiment described above contains a polyfunctional (meth)acrylate, a polyfunctional thiol, a reaction retarder, and quantum dots, and more preferably contains at least one of a scattering agent, a photopolymerization initiator, and a dispersion resin. The amounts of these substances are as described above.

[0063] A preferred embodiment of the quantum dot-containing composition of the present invention comprises a polyfunctional (meth)acrylate, a polyfunctional thiol, a reaction retarder, and quantum dots, and the reaction retarder comprises a dithiocarbamate compound. Among dithiocarbamate compounds, the inclusion of tetraethylthiuram disulfide makes it possible to obtain a good pot life.

[0064] Furthermore, a preferred embodiment of the quantum dot-containing composition in this embodiment comprises a polyfunctional (meth)acrylate, a polyfunctional thiol, a reaction retarder, a scattering agent, a photopolymerization initiator, and quantum dots, and is characterized in that the ratio of the number of moles of (meth)acrylate groups in the polyfunctional (meth)acrylate to the number of moles of mercapto groups in the polyfunctional thiol is in the range of 0.8 or more and 5.5 or less, or the ratio of the number of moles of (meth)acrylate groups in the polyfunctional (meth)acrylate to the number of moles of mercapto groups in the polyfunctional thiol is in the range of 1.52 or more and 9.0 or less.

[0065] The quantum dot-containing composition used in this embodiment may further contain known additives depending on the purpose, as long as the effects of this embodiment are not impaired. Examples of known additives include antioxidants, ultraviolet absorbers, antistatic agents, lubricants, surface conditioners, and viscosity modifiers. These may be used alone or in any combination of two or more.

[0066] Quantum dot-containing sheet member As shown in Fig. 2, by curing the quantum dot-containing composition of the present embodiment, for example, a quantum dot-containing sheet 1 containing quantum dots can be obtained. Here, the term "sheet" refers to a form in which the thickness is thinner than the plane, and may also be called a film.

[0067] 3, for example, a quantum dot layer (ink layer) 3 obtained by curing a quantum dot-containing composition on a substrate film 2 such as plastic can be formed to obtain a quantum dot-containing sheet 1 having a laminated structure. The quantum dot-containing sheet 1 may have the quantum dot layer 3 formed on one side of the substrate film 2. However, when applied to a backlight device described later, the quantum dot layer 3 is preferably in the form of a film. From the viewpoint of achieving excellent durability of the quantum dots (D), the quantum dot-containing sheet 1 preferably has a laminated structure in which the substrate film 2 is bonded to both sides of the film-like quantum dot layer 3, as shown in FIG. 4. When bonding the substrate film 2 and the quantum dot layer 3 together, they may be bonded using a known adhesive, or the quantum dot-containing composition of the present embodiment itself may be used as an adhesive and cured to bond them together.

[0068] An example of a schematic diagram of the quantum dot-containing sheet 1 used in this embodiment is shown in Figure 5. In Figure 5, the quantum dot-containing sheet 1 is formed in the shape of a thin plate (sheet or film) with a length dimension L, a width dimension W, and a thickness dimension T, and L, W, and T can be changed to optimal values ​​depending on the application. The quantum dot-containing sheet 1 may be formed with a constant thickness, or may have a shape in which the thickness varies depending on the location, or gradually changes in the length direction or width direction, or changes in stages.

[0069] Furthermore, the quantum dot-containing sheet 1 used in this embodiment is formed by curing a quantum dot-containing composition, and thus, compared to conventional methods, can more effectively suppress deterioration over time and discoloration of the quantum dot layer located near the end (edge) of the quantum dot-containing sheet 1. The reasons why deterioration can be suppressed by this embodiment are thought to be the core-shell structure of the quantum dots, the improved durability and dispersibility of the quantum dots themselves due to the ligands, the fact that the obtained quantum dot layer is a cured film with a high crosslink density due to the polyfunctional (meth)acrylate and polyfunctional thiol, and the fact that the polyfunctional thiol can effectively suppress the intrusion of oxygen.

[0070] The substrate film 2 of the quantum dot-containing sheet 1 used in this embodiment may include, but is not limited to, polyester, polypropylene, polyethylene, polystyrene, AS resin, ABS resin, acrylic resin, methacrylic resin, polyvinyl chloride, polyacetal, polyamide, polycarbonate, modified polyphenylene ether, polybutylene terephthalate, polyethylene terephthalate, polysulfone, polyethersulfone, polyphenylene sulfide, polyamideimide, polymethylpentene, liquid crystal polymer, epoxy resin, phenolic resin, urea resin, melamine resin, epoxy resin, diallyl phthalate resin, unsaturated polyester resin, polyimide, polyurethane, silicone resin, styrene-based thermoplastic elastomer, etc. These may be used alone or in any combination of two or more. Among these, polyester is preferred from the viewpoint of excellent light transmittance, thermal stability, dimensional stability, and adhesion between the substrate film 2 and the quantum dot layer 3, and polyethylene terephthalate is more preferred. In order to improve the adhesion between the quantum dot layer 3 and the substrate film 2, the substrate surface (the surface that comes into contact with the quantum dot layer 3) may be subjected to a pretreatment such as plasma treatment, corona treatment, or ozone treatment, or an adhesive layer (primer treatment) may be provided between the quantum dot layer 3 and the substrate film 2.

[0071] In this embodiment, the quantum dot layer thickness can be set to 50 μm or less, preferably 2 to 30 μm or less. The sheet thickness can be measured, for example, using a micrometer to obtain the average value of the sheet thickness measured at three or more points.

[0072] The surface (outer surface) of the base film of the quantum dot-containing sheet 1 used in this embodiment may be subjected to a matte treatment in order to efficiently take in excitation light and extract emitted light.

[0073] The total light transmittance of the quantum dot-containing sheet 1 used in this embodiment is preferably 55% or more, and more preferably 65% ​​or more. The total light transmittance is determined by measuring in accordance with the measurement method of JIS K 7136:2000.

[0074] The haze value of the quantum dot-containing sheet 1 in this embodiment is preferably 85% or more, more preferably 90% or more, and even more preferably 95% or more, in order to enable efficient use of excitation light. The haze value is determined by measurement in accordance with the measurement method of JIS K 7136:2000.

[0075] The quantum dot-containing sheet 1 of this embodiment can be incorporated into, for example, a backlight device 55 shown in Fig. 6. In Fig. 6, the backlight device 55 is configured with a plurality of light-emitting elements 20 (LEDs) and the quantum dot-containing sheet 1 of this embodiment facing the light-emitting elements 20. As shown in Fig. 6, each light-emitting element 20 is supported on the surface of a support 52. In Fig. 6, the backlight device 55 is arranged on the back side of a display unit 54 such as a liquid crystal display to configure a display device 50.

[0076] Although not shown in Figure 6, in addition to the quantum dot-containing sheet 1, a diffusion plate that diffuses light and other sheets may be interposed between the light-emitting element 20 and the display unit 54.

[0077] 6 is formed from a single sheet, it is also possible to join multiple quantum dot-containing sheets 1 together to obtain a predetermined size. Hereinafter, a configuration in which multiple quantum dot-containing sheets 1 are joined together by tiling will be referred to as a composite quantum dot-containing sheet.

[0078] Here, we consider a configuration in which a composite quantum dot-containing sheet is placed in place of the quantum dot-containing sheet 1 of the display device 50 in Figure 6, and a diffuser is placed between the light-emitting element 20 and the composite quantum dot-containing sheet, i.e., a configuration of light-emitting element 20 / diffuser / composite quantum dot-containing sheet / display unit 54. In this configuration, light emitted from the light-emitting element 20 and diffused by the diffuser is incident on the composite quantum dot-containing sheet. Because the light diffused by the diffuser is incident on the composite quantum dot-containing sheet, the light intensity distribution due to the distance from the light-emitting element 20 is suppressed. Furthermore, since the distance between the light-emitting element 20 and the composite quantum dot-containing sheet is greater than when a diffuser is not present, the impact of heat generated by the light-emitting element 20 on the quantum dots contained in the composite sheet is reduced.

[0079] 7, the light emitting elements 20, the quantum dot-containing sheet 21, the diffusion plate 22, and the display unit 54 may be arranged in this order. This allows appropriate suppression of color unevenness in the display of the display unit 54, even if unevenness in the emitted light occurs at the joints of the quantum dot-containing sheets 1 due to diffuse reflection or deterioration of the quantum dots due to water vapor entering through the joints. That is, the light emitted from the quantum dot-containing sheet 21 is diffused by the diffusion plate 22 before entering the display unit 54, thereby suppressing color unevenness in the display of the display unit 54.

[0080] When the quantum dot-containing sheet 21 is used, it is preferable to place a diffusion plate on the light-emitting surface side of the quantum dot-containing sheet 21, regardless of whether it is applied to the display device shown in FIG.

[0081] As shown in FIG. 8 , the quantum dot-containing sheet 1 of this embodiment can be incorporated into a liquid crystal display element 60. The liquid crystal display element 60 includes, from the bottom, a direct-type LED sheet 80, a partial reflection sheet (partial reflection layer) 81, a prism sheet 63, a diffusion sheet 64, a polarizing plate 65, a retardation film 66, a liquid crystal cell 67 composed of a glass substrate / liquid crystal / color filter, a retardation film 68, and a polarizing plate 69, stacked in this order. A dichroic filter (e.g., "BLT" manufactured by 3M) can be used as the partial reflection sheet. The quantum dot-containing sheet 1 is provided on the surface of the partial reflection sheet 81. The quantum dot-containing sheet 1 may be coated on the surface of the partial reflection sheet 81, or the quantum dot-containing sheet 1 may be a sheet and the quantum dot-containing sheet 1 may be attached to the surface of the partial reflection sheet 81.

[0082] FIG. 8 shows a direct type in which a plurality of LEDs are arranged directly below the light source, and the direct type is used for large displays and the like.

[0083] The LED emits blue light. Therefore, part of the blue light is transmitted through the partial reflection sheet 81 and is wavelength-converted to red light and / or green light in the quantum dot-containing sheet 1. The wavelength-converted red light and green light are emitted upward by the partial reflection sheet 81, not downward.

[0084] Here, when a blue LED is used, in a configuration without a partial reflection sheet 81, color unevenness and brightness unevenness (halo phenomenon) may occur due to diffusion, diffuse reflection, etc., when the blue light is wavelength-converted by the quantum dot-containing sheet 1. Therefore, by providing a partial reflection sheet 81 as in the present embodiment, it is possible to suppress the halo phenomenon. This is particularly effective when the number of LEDs is increased in a direct-type LED, as shown in FIG. 8. Furthermore, by reducing the transmission of blue light with the partial reflection sheet 81, the amount of blue light reused can be increased, thereby improving brightness (luminous intensity). Therefore, high brightness can be obtained even if the quantum dots do not contain regulated heavy metals such as Cd and Pb.

[0085] The quantum dot-containing sheet 1 used in this embodiment can more effectively suppress changes in luminescence intensity over time than conventional ones. Therefore, when the quantum dot-containing sheet 1 of this embodiment is used in a backlight device 55, a liquid crystal display element, or the like, the wavelength conversion characteristics can be stabilized, and the life of the backlight device 55 or the liquid crystal display element can be extended.

[0086] The quantum dot-containing sheet 1 used in this embodiment can be in the form of a flexible sheet, so that the quantum dot-containing sheet 1 can be appropriately placed on a curved surface or the like.

[0087] The quantum dot-containing sheet 1 used in this embodiment can ensure a normalized illuminance of 0.6 or more after 1000 hours of durability testing, for example. Preferably, the normalized illuminance is 0.75 or more, more preferably, 0.85 or more, and even more preferably, 0.9 or more.

[0088] 9, the quantum dot-containing sheet 1 of this embodiment can have a structure in which the substrate film 2 is provided on only one side of the quantum dot layer 3, and the optical member 70 is in contact with the surface of the quantum dot layer 3 opposite the substrate film 2. This allows one side of the quantum dot layer 3 to be protected by the substrate film 2, while the optical member 70 can be closely attached to the surface opposite the quantum dot layer 3. A light guide plate or a diffusion plate can be preferably used as the optical member 70. This quantum dot-containing sheet 1 can be used in backlight devices, display devices, and lighting devices.

[0089] The quantum dot-containing sheet 1 shown in FIG. 9 can be formed by applying the quantum dot-containing composition of the present embodiment directly to the surface of the optical member 70, then overlaying the substrate film 2 and thermally curing the composition to form a laminated structure of the optical member / quantum dot layer / substrate film.

[0090] 10 , the surface of a quantum dot-containing sheet 71 having a substrate film 2 provided on only one side of the quantum dot layer 3, on which the substrate film 2 is not provided, is placed facing an optical member 70, and the quantum dot-containing sheet 71 and the optical member 70 are brought into close contact with each other. At this time, the quantum dot-containing sheet 71 and the optical member 70 may be joined via an adhesive layer, or the quantum dot-containing sheet 71 may be directly brought into close contact with the surface of the optical member 70.

[0091] 11A , the quantum dot-containing sheet 71 includes, for example, a first substrate film 73 bonded to one side of the quantum dot layer 3 via a primer layer 72, and a second substrate film 74 bonded directly to the surface of the quantum dot layer 3 opposite the first substrate film 73. This allows both sides of the quantum dot layer 3 to be protected by the substrate films 73 and 74. As an example, the substrate films 73 and 74 can be formed from PET films. Alternatively, the first substrate film 73 can be a PET film, and the second substrate film 74 can be a PE film. Alternatively, a PEN (polyethylene naphthalate) film can be used instead of the PET film or PE film.

[0092] In the quantum dot-containing sheet 71, the adhesion between the first base film 73 and the quantum dot layer 3 is stronger than the adhesion between the second base film 74 and the quantum dot layer 3. Then, as shown in Fig. 10, when the quantum dot-containing sheet 71 is attached to the surface of the optical member 70, the quantum dot-containing sheet 1 shown in Fig. 9 can be obtained by going through a step of peeling off the second base film 74 of the quantum dot-containing sheet 71 and a step of attaching the surface of the quantum dot layer 3 exposed by peeling it to the surface of the optical member 70.

[0093] A conceptual diagram showing a manufacturing apparatus for manufacturing the quantum dot-containing sheet 1 of this embodiment is shown in Fig. 12. Fig. 12 discloses an example of a manufacturing method for the quantum dot-containing sheet 1, which is formed by applying a quantum dot-containing composition to the substrate film 2 shown in Fig. 4 and curing the composition to form the quantum dot layer 3.

[0094] As shown in Figure 12, the apparatus is configured to include a first raw roll 30a that feeds out a resin film 10a that becomes the base film 2, a second raw roll 30b that feeds out a resin film 10b that similarly becomes the base film 2, a take-up roll 32, a joining section 35 formed by a pair of nip rolls 33 and 34, an application means 36, a drying section 38, and a curing reaction section 41.

[0095] 12 , a resin film 10a is fed from a first raw roll 30a, and a quantum dot-containing composition 37 containing quantum dots is applied to the surface of the resin film 10a using a coating means 36. Examples of methods for applying the quantum dot-containing composition 37 include coating methods using a known coating coater or impregnation coating coater. Examples include a gravure coater, curtain coater, dip coater, comma knife coater, die coater, and roll coater.

[0096] 12, the resin film 10a having the quantum dot-containing composition 37 applied to its surface is heated in a drying section 38 equipped with a heating device such as a heater or a hot air oven, and the solvent contained therein is evaporated. Note that if the quantum dot-containing composition 37 does not contain a solvent, the drying section 38 need not be used.

[0097] Next, in the bonding section 35, a pressure bonding device bonds the interface between the quantum dot-containing composition 37 applied to the resin film 10a and the resin film 10b fed from the second raw roll 30b. During bonding, heat may be applied as necessary. Note that if the quantum dot layer 3 is not sandwiched between the resin films 10a and 10b, the above bonding operation is not necessary.

[0098] Next, the layer is irradiated with active energy rays in a curing reaction section 40 equipped with an active energy ray irradiator such as an ultraviolet ray irradiator or an electron beam irradiator, thereby forming a hardened quantum dot layer 3 (see FIG. 4 ). The active energy ray irradiation may be performed before or after the bonding step at the bonding section 35.

[0099] Then, a sheet-like quantum dot-containing sheet 39 consisting of the resin film 10a / quantum dot layer 3 / resin film 10b is taken up by a take-up roll 32. The taken-up quantum dot-containing sheet 39 is cut to a predetermined size to obtain the quantum dot-containing sheet 1 having the predetermined shape shown in Fig. 4. The quantum dot-containing composition 37 of this embodiment has an excellent pot life, and the quantum dot-containing sheet 39 can be mass-produced.

[0100] In order to allow the curing reaction to proceed completely, the quantum dot-containing sheet 1 of this embodiment can be aged for an appropriate time in an environment at an appropriate aging temperature. The appropriate aging temperature is not limited to the following, but is preferably in the range of 20 to 60°C, and more preferably in the range of 30 to 50°C. The appropriate aging time is preferably in the range of 6 to 48 hours, and more preferably in the range of 10 to 24 hours.

[0101] The average thickness of the quantum dot layer 3 in the quantum dot-containing sheet 1 of this embodiment is not limited to the following, but is preferably in the range of 70 μm, preferably 50 μm or less, and more preferably 2 to 30 μm. The average thickness of the quantum dot layer 3 in the quantum dot-containing sheet 1 is calculated, for example, by measuring the thickness of the quantum dot-containing sheet 1 at three or more points using a micrometer, and then subtracting the average thickness of half the base film used from the average thickness.

[0102] Furthermore, using the manufacturing apparatus shown in FIG. 12, it is possible to manufacture a quantum dot-containing sheet 71 in which the adhesion strength between the quantum dot layer 3 and the substrate film 73 is varied by providing a primer layer 72 on only one side of the quantum dot layer 3, as shown in FIG. 11A.

[0103] 12, it is possible to manufacture a quantum dot-containing film member in which a substrate film is provided on only one side of the quantum dot layer. In this case, there is no need to use the second raw roll 30b and nip rolls 33 and 34.

[0104] The effects of the present invention will be explained below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0105] <Quantum Dot Experiment> In this example, I-III-VI type chalcopyrite quantum dots containing no RoHS-regulated substances were fabricated as cadmium-free quantum dots. Specifically, Ag—Ga—S quantum dots were fabricated. As a comparative example, commercially available InP was used.

[0106] The graph shown in Figure 13A shows experimental results for green quantum dots, with the horizontal axis representing wavelength and the vertical axis representing absorption coefficient. As shown in Figure 13A, it was found that the chalcopyrite quantum dots of this example have a higher absorption coefficient at 450 nm than InP. The absorption coefficient at 450 nm for this example is about 5 times, preferably about 6 times, and more preferably about 7 times, higher than that of the comparative example (in experiments, it was about 6 times, preferably about 7 times).

[0107] The graph in Figure 13B shows experimental results for red quantum dots, with the horizontal axis representing wavelength and the vertical axis representing absorption coefficient. As shown in Figure 14, the chalcopyrite quantum dots of this example were found to have a higher absorption coefficient at 450 nm than InP. The absorption coefficient at 450 nm for this example was approximately 1.5 times, preferably approximately 2 times, higher than that of the comparative example.

[0108] The upper part of Figure 13C shows EDX mapping of Ag and Ga in the quantum dots of this example, and the lower part is a schematic diagram showing a portion of the mapping. The more Ag and Ga detected, the darker the blue color. This shows that Ag and Ga are mainly present in the core of the quantum dots.

[0109] The upper part of Figure 13D shows EDX mapping of Zn and S in the quantum dots of this example, and the lower part is a schematic diagram showing a portion of the mapping. The more Zn and S detected, the darker the yellow color. This indicates that Zn and S are mainly present in the shells of the quantum dots.

[0110] Next, the following quantum dot-containing compositions were formed: First, the methods for measuring various physical properties will be described.

[0111] <Measurement of Number Average Molecular Weight> The number average molecular weight was measured by gel permeation chromatography (GPC) using a dispersion resin as a sample. For samples soluble in tetrahydrofuran, tetrahydrofuran was used as the eluent, and the measurement was performed using a Tosoh Corporation HLC-8220 GPC system equipped with two TSKgel Super HZM-N columns connected as the measuring instrument, under conditions of a column temperature of 40°C and a flow rate of 0.35 ml per minute. The sample was prepared by dissolving 2 mg of the sample in 5 ml of the above eluent. The number average molecular weight was calculated in terms of standard polystyrene. Note that the number average molecular weight was not calculated for samples that were insoluble in the eluent or samples that could not be measured due to adsorption to the column, etc.

[0112] <Measurement of quantum yield> Using quantum dots and quantum dot-containing sheets as samples, the quantum yield of luminescence was measured at an excitation wavelength of 450 nm using an absolute PL quantum yield measurement device (Quantaurus-QY C11347-01, manufactured by Hamamatsu Photonics K.K.) Note that for the quantum dots, a toluene solution prepared so that the absorbance at 450 nm when using a 1 cm cell was 1 was used as the sample.

[0113] <Measurement of Emission Peak Wavelength and Half-Width> Using quantum dots as samples, the emission peak wavelength and half-width were measured using a spectrofluorometer (FP-8500, manufactured by JASCO Corporation) at an excitation wavelength of 450 nm. Note that a toluene solution of quantum dots prepared so that the absorbance at 450 nm when using a 1 cm cell was 1 was used as the sample. <Viscosity Measurement> Using the quantum dot-containing composition described below as a sample, viscosity was measured at 25°C using a B-type viscometer (TVB-10M, manufactured by Toki Sangyo Co., Ltd.).

[0114] <Measurement of Film Thickness> The thickness of the quantum dot-containing sheet obtained as described below was measured at three or more points using a micrometer (high-precision digimatic micrometer MDH-25MB, manufactured by Mitutoyo Corporation), and the thickness was determined from the average value.

[0115] <Measurement of total light transmittance and haze> The quantum dot-containing sheet obtained below was cut into a sample having a width of 50 mm and a length of 50 mm, and the total light transmittance and haze value were measured three times using a spectroscopic haze meter (SH7000, manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with the measurement method of JIS K 7136: 2000. The average values ​​of the three measurements were used as the total light transmittance and haze value.

[0116] <Quantum Dots> In the experiment, quantum dot powders with an emission peak wavelength of 530 nm (green), a half-width of 30 nm, and an emission quantum yield of 90% in toluene solution (hereinafter referred to as green quantum dots) were used, and quantum dot powders with an emission peak wavelength of 630 nm (red), a half-width of 30 nm, and an emission quantum yield of 90% in toluene solution (hereinafter referred to as red quantum dots) were used. Both of these are I-III-VI type chalcopyrites and have a higher absorption coefficient at 450 nm than InP.

[0117] <Production of Dispersion Resins> Dispersion resins (G-1) to (G-6) were produced according to the following method. Table 1 shows the raw materials and their blending amounts, as well as the properties of the resulting dispersion resins.

[0118] <Production Example (1)> A reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping tube, and nitrogen inlet tube was charged with 25.8 parts of toluene, 56.6 parts of n-butyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), and 3.5 parts of pentaerythritol tetrakis(3-mercaptopropionate) (manufactured by Tokyo Chemical Industry Co., Ltd.) while blowing nitrogen gas into the reaction vessel, and the mixture was stirred at room temperature for 30 minutes. Next, after heating to 90 ° C, a solution of 0.02 parts of 2,2'-azobis(isobutyronitrile) dissolved in 2.5 parts of toluene was added dropwise over 6 hours, and then the mixture was stirred for another 3 hours at 90 ° C to allow the polymerization reaction. Thereafter, the reaction solution was cooled to room temperature, and the solvent was removed by vacuum drying to obtain a solid dispersion resin (G-1). Note that "parts" refers to "parts by mass." The same applies to the following experiments. The dispersion resin (G-1) thus obtained was an acrylic resin having a number average molecular weight of 2,500 and containing a mercapto group.

[0119] <Production Example (2)> A reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping tube, and nitrogen inlet tube was charged with 25.7 parts of toluene, 28.9 parts of n-butyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), 28.9 parts of 2-ethylhexyl methacrylate, and 2.1 parts of pentaerythritol tetrakis(3-mercaptopropionate) (manufactured by Tokyo Chemical Industry Co., Ltd.) while blowing nitrogen gas into the reaction vessel, and the mixture was stirred at room temperature for 30 minutes. Next, after heating to 90 ° C, a solution of 0.02 parts of 2,2'-azobis(isobutyronitrile) dissolved in 2.5 parts of toluene was added dropwise over 6 hours, and then the mixture was stirred for another 3 hours at 90 ° C to allow the polymerization reaction. Thereafter, the reaction solution was cooled to room temperature, and the solvent was removed by vacuum drying to obtain a viscous liquid dispersion resin (G-2). The dispersion resin (G-2) thus obtained was an acrylic resin having a number average molecular weight of 3,300 and a mercapto group.

[0120] <Production Example (3)> A reaction vessel equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and vacuum piping was charged with 86.9 parts of pentaerythritol tetrakis (3-mercaptopropionate) (manufactured by Tokyo Chemical Industry Co., Ltd.), and the pressure in the reaction vessel was reduced with stirring using a vacuum pump and maintained for 30 minutes. Thereafter, 13.0 parts of tris (2-acryloyloxyethyl) isocyanurate (manufactured by Tokyo Chemical Industry Co., Ltd.) heated to 60 ° C. was added with stirring, and the mixture was stirred until homogeneous. 0.1 parts of triethylamine was added, and the mixture was stirred for 3 hours to obtain a viscous liquid dispersion resin (G-3). The dispersion resin (G-3) thus obtained was a thioether resin having a number average molecular weight of 2100 and a mercapto group.

[0121] <Production Example (4)> SOLSPERSE (registered trademark) 24000GR (a polyethyleneimine resin having an amino group, manufactured by Lubrizol Japan Co., Ltd.) was used as the dispersing resin (G-4).

[0122] Production Example (5) AJISPER (registered trademark) PB821 (manufactured by Ajinomoto Fine-Techno Co., Inc., polyester resin having an amino group) was used as the dispersing resin (G-5).

[0123] <Production Example (6)> DISPERBYK (registered trademark)-111 (manufactured by BYK Japan, polyester resin having a phosphate group) was used as the dispersing resin (G-6).

[0124]

[0125] <Production of Quantum Dot-Containing Compositions> Quantum dot-containing compositions (X-1) to (X-21) were produced according to the following method. Tables 2 and 3 show the blending amounts of raw materials used in the production and the results of the pot life evaluation described below.

[0126] Experimental Example 1 60 parts of A-DCP (dimethylol-tricyclodecane diacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd., (meth)acrylate group amount: 6.58 mmol / g) as the polyfunctional (meth)acrylate (A), EGMP-4 (tetraethylene glycol, manufactured by SC Organic Chemical Co., Ltd.) as the polyfunctional thiol (B) were used. 40 parts of bis(3-mercaptopropionate), mercapto group amount 5.38 mmol / g), 1 part of hydroquinone (manufactured by Tokyo Chemical Industry Co., Ltd.) as a reaction retarder (C), 0.4 parts of green quantum dots, 0.07 parts of red quantum dots as quantum dots (D), 5 parts of Eposter (registered trademark) MS (manufactured by Nippon Shokubai Co., Ltd., benzoguanamine-formaldehyde condensate particles) as a scattering agent (E), 0.3 parts of Irgacure (registered trademark) 184 (manufactured by BASF) as a photopolymerization initiator (F), 1.37 parts of dispersion resin (G-1) as a dispersion resin (G) were blended, and the mixture was gently shaken by hand, and then stirred with a homodisper until the whole was uniform. In the quantum dot-containing composition (X-1) thus obtained, the ratio of the number of moles of (meth)acrylate groups in the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups in the polyfunctional thiol (B) was 1.84.

[0127] Experimental Example 2 A mixture of 50 parts of A-TMPT (manufactured by Shin-Nakamura Chemical Co., Ltd., trimethylolpropane triacrylate, (meth)acrylate group amount: 10.0 mmol / g) as the polyfunctional (meth)acrylate (A), 5 parts of Shikoh UV-7650B (manufactured by Nippon Synthetic Chemicals, urethane acrylate resin, acrylate group amount: 0.0004 parts), and 5 parts of TMMP (manufactured by SC Organic Chemical Co., Ltd., trimethylolpropane tris(3-mercaptopropionate), mercapto group amount: 7.53 mmol / g) as the polyfunctional thiol (B) was used. ) 45 parts, reaction retarder (C) triphenyl phosphite (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.5 parts, quantum dots (D) as, 0.4 parts green quantum dots, 0.07 parts red quantum dots, scattering agent (E) Eposter MS (manufactured by Nippon Shokubai Co., Ltd., benzoguanamine-formaldehyde condensate particles) 5 parts, photopolymerization initiator (F) Irgacure 184 (manufactured by BASF) 0.6 parts, blended, gently shaken by hand, and then stirred until the whole was uniform with a homodisper. The ratio of the number of moles of (meth)acrylate groups of the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups of the polyfunctional thiol (B) of the quantum dot-containing composition (X-2) thus obtained was 1.48.

[0128] Experimental Example 3 20 parts of A-TMPT (manufactured by Shin-Nakamura Chemical Co., Ltd., trimethylolpropane triacrylate, (meth)acrylate group amount 10.0 mmol / g) as the polyfunctional (meth)acrylate (A), 30 parts of AD-TMP (manufactured by Shin-Nakamura Chemical Co., Ltd., ditrimethylolpropane tetraacrylate, (meth)acrylate group amount 8.51 mmol / g), 50 parts of PEMP (manufactured by SC Organic Chemical Co., Ltd., pentaerythritol tetrakis(3-mercaptopropionate), mercapto group amount 8.19 mmol / g) as the polyfunctional thiol (B), and a reaction delay As the agent (C), tetraethyl thiuram disulfide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as 0.002 parts, quantum dots (D) were used as 0.4 parts of green quantum dots, and red quantum dots were used as 0.07 parts, scattering agent (E) was used as 5 parts of Techpolymer (registered trademark) MBX-5 (manufactured by Sekisui Plastics Co., Ltd., cross-linked polymethyl methacrylate particles), photopolymerization initiator (F) was used as 0.2 parts of Irgacure 184 (manufactured by BASF), and dispersion resin (G) was used as 1.37 parts of dispersion resin (G-4), which was gently shaken by hand and then stirred until the entire mixture was uniform with a homodisper. The ratio of the number of moles of (meth)acrylate groups in the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups in the polyfunctional thiol (B) of the quantum dot-containing composition (X-3) thus obtained was 1.12.

[0129] Experimental Example 4 45 parts of AD-TMP (manufactured by Shin-Nakamura Chemical Co., Ltd., ditrimethylolpropane tetraacrylate, (meth)acrylate group content: 8.51 mmol / g) as the polyfunctional (meth)acrylate (A), 40 parts of PEMP (manufactured by SC Organic Chemical Industry, pentaerythritol tetrakis(3-mercaptopropionate), mercapto group content: 8.19 mmol / g) as the polyfunctional thiol (B), 40 parts of DPMP (manufactured by SC Organic Chemical Industry, dipentaerythritol hexakis(3-mercaptopropionate), mercapto group content: 7.66 mmol / g) ) 15 parts, reaction retarder (C) triphenyl phosphite (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.3 parts, quantum dots (D) as, 0.4 parts green quantum dots, 0.07 parts red quantum dots, scattering agent (E) D-918 (manufactured by Sakai Chemical Industry Co., Ltd., rutile type titanium oxide) 0.25 parts, Optobeads (registered trademark) 2000M (manufactured by Nissan Chemical Co., Ltd., melamine resin-silica composite particles) 4 parts, photopolymerization initiator (F) Irgacure TPO (manufactured by BASF) 0.3 parts, dispersion resin (G) as dispersion resin (G-6) 1.37 parts were blended, and after gently shaking by hand, the whole was stirred until uniform with a homodisper. The ratio of the number of moles of acrylate groups of the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups of the polyfunctional thiol (B) of the quantum dot-containing composition (X-4) thus obtained was 0.87.

[0130] Experimental Example 5 80 parts of A-TMPT (manufactured by Shin-Nakamura Chemical Co., Ltd., trimethylolpropane triacrylate, (meth)acrylate group amount: 10.0 mmol / g) as the polyfunctional (meth)acrylate (A), 20 parts of TMMP (manufactured by SC Organic Chemical Industry Co., Ltd., trimethylolpropane tris(3-mercaptopropionate), mercapto group amount: 7.53 mmol / g) as the polyfunctional thiol (B), 0.001 parts of tetraethylthiuram disulfide (manufactured by Tokyo Chemical Industry Co., Ltd.) as the reaction retarder (C), 0.001 parts of tetraethylthiuram disulfide (manufactured by Tokyo Chemical Industry Co., Ltd. ... As dots (D), 0.4 parts of green quantum dots, 0.07 parts of red quantum dots, 0.2 parts of D-918 (manufactured by Sakai Chemical Industry Co., Ltd., R-type titanium oxide) as scattering agent (E), 6 parts of Optobeads 2000M (manufactured by Nissan Chemical Co., Ltd., melamine resin-silica composite particles), 0.8 parts of Irgacure TPO (manufactured by BASF) as photopolymerization initiator (F), 1.37 parts of dispersion resin (G-6) as dispersion resin (G) were blended, and after gently shaking by hand, the whole was stirred until uniform with a homodisper. The ratio of the number of moles of (meth)acrylate groups of the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups of the polyfunctional thiol (B) was 5.31.

[0131] Experimental Example 6 50 parts of A-TMPT (manufactured by Shin-Nakamura Chemical Co., Ltd., trimethylolpropane triacrylate, (meth)acrylate group amount: 10.0 mmol / g) as the polyfunctional (meth)acrylate (A), 5 parts of A-DPH (manufactured by Shin-Nakamura Chemical Co., Ltd., dipentaerythritol hexaacrylate, (meth)acrylate group amount: 0.010 mmol / g), 35 parts of PEMP (manufactured by SC Organic Chemical Co., Ltd., pentaerythritol tetrakis(3-mercaptopropionate), mercapto group amount: 8.19 mmol / g) as the polyfunctional thiol (B), DPMP (manufactured by SC Organic Chemical Co., Ltd., dipentaerythritol hexakis(3-mercaptopropionate), mercapto group amount: 7.66 mmol / g), and ) 10 parts, reaction retarder (C) triphenyl phosphite (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.3 parts, quantum dots (D) as, 0.4 parts green quantum dots, 0.07 parts red quantum dots, scattering agent (E) Eposter MS (manufactured by Nippon Shokubai Co., Ltd., benzoguanamine-formaldehyde condensate particles) 7 parts, photopolymerization initiator (F) Irgacure 184 (manufactured by BASF) 0.8 parts, dispersion resin (G) as dispersion resin (G-3) 1.37 parts were blended, and after gently shaking by hand, the whole was stirred until uniform with a homodisper. The ratio of the number of moles of (meth)acrylate groups of the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups of the polyfunctional thiol (B) of the quantum dot-containing composition (X-6) thus obtained was 1.52.

[0132] Experimental Example 7 50 parts of A-TMPT (manufactured by Shin-Nakamura Chemical Co., Ltd., trimethylolpropane triacrylate, (meth)acrylate group amount 10.0 mmol / g) as the polyfunctional (meth)acrylate (A), 15 parts of AD-TMP (manufactured by Shin-Nakamura Chemical Co., Ltd., trimethylolpropane triacrylate, (meth)acrylate group amount 10.0 mmol / g), 35 parts of PEMP (manufactured by SC Organic Chemical Co., Ltd., pentaerythritol tetrakis(3-mercaptopropionate), mercapto group amount 8.19 mmol / g) as the polyfunctional thiol (B), and a reaction delay As the agent (C), tetraethyl thiuram disulfide (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.002 parts, as quantum dots (D), 0.4 parts of green quantum dots, 0.07 parts of red quantum dots, as scattering agent (E), D-918 (manufactured by Sakai Chemical Industry Co., Ltd., rutile-type titanium oxide) 1.0 parts, as photopolymerization initiator (F) Irgacure 184 (manufactured by BASF) 0.4 parts, as dispersion resin (G) dispersion resin (G-1) 1.0 parts, dispersion resin (G-6) 1.37 parts were blended, and after gently shaking by hand, the whole was stirred until uniform with a homodisper. The quantum dot-containing composition (X-7) thus obtained, the ratio of the number of moles of (meth)acrylate groups of the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups of the polyfunctional thiol (B) was 2.19.

[0133] Experimental Example 8 40 parts of A-TMPT (manufactured by Shin-Nakamura Chemical Co., Ltd., trimethylolpropane triacrylate, (meth)acrylate group amount: 10.0 mmol / g) as the polyfunctional (meth)acrylate (A), 15 parts of AD-TMP (manufactured by Shin-Nakamura Chemical Co., Ltd., ditrimethylolpropane tetraacrylate, (meth)acrylate group amount: 8.51 mmol / g), and Karenz (registered trademark) MT as the polyfunctional thiol (B) were mixed. 45 parts of PE1 (Showa Denko K.K., pentaerythritol tetrakis (3-mercaptobutyrate), mercapto group amount 7.34 mmol / g), 0.002 parts of tetraethyl thiuram disulfide (Tokyo Chemical Industry Co., Ltd.) as a reaction retarder (C), 0.4 parts of green quantum dots as quantum dots (D), 0.07 parts of red quantum dots, 5 parts of Eposter MS (Nippon Shokubai Co., Ltd., benzoguanamine formaldehyde condensate particles) as a scattering agent (E), 0.3 parts of Irgacure 184 (BASF) as a photopolymerization initiator (F), 1.37 parts of dispersion resin (G-2) as a dispersion resin (G) were blended, and the mixture was gently shaken by hand, and then stirred with a homodisper until the whole was uniform. In the quantum dot-containing composition (X-8) thus obtained, the ratio of the number of moles of (meth)acrylate groups in the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups in the polyfunctional thiol (B) was 1.60.

[0134] Experimental Example 9 50 parts of A-TMPT (manufactured by Shin-Nakamura Chemical Co., Ltd., trimethylolpropane triacrylate, (meth)acrylate group amount: 10.0 mmol / g) as the polyfunctional (meth)acrylate (A), 10 parts of AD-TMP (manufactured by Shin-Nakamura Chemical Co., Ltd., ditrimethylolpropane tetraacrylate, (meth)acrylate group amount: 8.51 mmol / g), 40 parts of PEMP (manufactured by SC Organic Chemical Co., Ltd., pentaerythritol tetrakis(3-mercaptopropionate), mercapto group amount: 8.19 mmol / g) as the polyfunctional thiol (B), and tetraethylthiuramdisulfide (Tetraethylthiuramdisulfide) as the reaction retarder (C). Rufide (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.003 parts, quantum dots (D), 0.4 parts of green quantum dots, 0.07 parts of red quantum dots, scattering agent (E), D-918 (manufactured by Sakai Chemical Industry Co., Ltd., rutile-type titanium oxide) 0.2 parts, Optobeads 2000M (manufactured by Nissan Chemical Industries, melamine resin-silica composite particles) 4.5 parts, photopolymerization initiator (F) Irgacure 184 (manufactured by BASF) 0.2 parts, Irgacure TPO 0.1 parts, dispersion resin (G) as dispersion resin (G-4) 1.37 parts were blended, and after gently shaking by hand, the whole was stirred until uniform with a homodisper. The quantum dot-containing composition (X-9) thus obtained, the ratio of the number of moles of (meth)acrylate groups of the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups of the polyfunctional thiol (B) was 1.79.

[0135] Experimental Example 10 50 parts of A-TMPT (manufactured by Shin-Nakamura Chemical Co., Ltd., trimethylolpropane triacrylate, (meth)acrylate group amount: 10.0 mmol / g) as the polyfunctional (meth)acrylate (A), 10 parts of AD-TMP (manufactured by Shin-Nakamura Chemical Co., Ltd., ditrimethylolpropane tetraacrylate, (meth)acrylate group amount: 8.51 mmol / g), 40 parts of PEMP (manufactured by SC Organic Chemical Co., Ltd., pentaerythritol tetrakis(3-mercaptopropionate), mercapto group amount: 8.19 mmol / g) as the polyfunctional thiol (B), and tetraethylthiuramdisulfide (Tetraethylthiuramdisulfide) as the reaction retarder (C). Rufide (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.003 parts, quantum dots (D), 0.4 parts of green quantum dots, 0.07 parts of red quantum dots, scattering agent (E), D-918 (manufactured by Sakai Chemical Industry Co., Ltd., rutile-type titanium oxide) 0.2 parts, Optobeads 2000M (manufactured by Nissan Chemical Co., Ltd., melamine resin-silica composite particles) 4.5 parts, photopolymerization initiator (F) Irgacure 184 (manufactured by BASF) 0.2 parts, Irgacure TPO 0.1 parts, dispersion resin (G) as dispersion resin (G-5) 1.37 parts were blended, and after gently shaking by hand, the whole was stirred until uniform with a homodisper. The quantum dot-containing composition (X-10) thus obtained, the ratio of the number of moles of acrylate groups of the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups of the polyfunctional thiol (B) was 1.79.

[0136] Experimental Example 11 A mixture of 50 parts of A-TMPT (manufactured by Shin-Nakamura Chemical Co., Ltd., trimethylolpropane triacrylate, (meth)acrylate group amount: 10.0 mmol / g) and 10 parts of AD-TMP (manufactured by Shin-Nakamura Chemical Co., Ltd., ditrimethylolpropane tetraacrylate, (meth)acrylate group amount: 8.51 mmol / g) as the polyfunctional (meth)acrylate (A) and 30 parts of PEMP (manufactured by SC Organic Chemical Industry, pentaerythritol tetrakis(3-mercaptopropionate), mercapto group amount: 8.19 mmol / g) and DPMP (manufactured by SC Organic Chemical Industry, dipentaerythritol hexakis(3-mercaptopropionate), mercapto group amount: 7.66 mmol / g) as the polyfunctional thiol (B) was used. ) 10 parts, reaction retarder (C) tetraethyl thiuram disulfide (Tokyo Chemical Industry Co., Ltd.) 0.003 parts, quantum dots (D) as, 0.4 parts of green quantum dots, 0.07 parts of red quantum dots, scattering agent (E), D-918 (Sakai Chemical Industry Co., Ltd., rutile type titanium oxide) 0.2 parts, Optobeads 2000M (Nissan Chemical Co., Ltd., melamine resin / silica composite particles) 4.5 parts, photopolymerization initiator (F) Irgacure 184 (BASF Corporation) 0.2 parts, Irgacure TPO 0.1 parts, dispersion resin (G) as dispersion resin (G-6) 1.37 parts were blended, and after shaking lightly by hand, it was stirred until the whole was uniform with a homodisper. In the quantum dot-containing composition (X-11) thus obtained, the ratio of the number of moles of (meth)acrylate groups in the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups in the polyfunctional thiol (B) was 1.82.

[0137] Experimental Example 12: 100 parts of A-TMPT (manufactured by Shin-Nakamura Chemical Co., Ltd., trimethylolpropane triacrylate, (meth)acrylate group amount 10.0 mmol / g) as polyfunctional (meth)acrylate (A), 0.002 parts of tetraethyl thiuram disulfide (manufactured by Tokyo Chemical Industry Co., Ltd.) as reaction retarder (C), 0.4 parts of green quantum dots as quantum dots (D), 0.07 parts of red quantum dots, 5 parts of Eposter MS (manufactured by Nippon Shokubai Co., Ltd., benzoguanamine-formaldehyde condensate particles) as scattering agent (E), 0.4 parts of Irgacure 184 (manufactured by BASF) as photopolymerization initiator (F), 1.37 parts of dispersion resin (G-6) as dispersion resin (G) were blended, and the mixture was gently shaken by hand, and then stirred with a homodisper until the whole was uniform. In the quantum dot-containing composition (X-12) thus obtained, the ratio of the number of moles of (meth)acrylate groups in the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups in the polyfunctional thiol (B) was 1 / 0 (infinity due to division by zero).

[0138] Experimental Example 13 100 parts of TMMP (manufactured by SC Organic Chemical Industry Co., Ltd., trimethylolpropane tris (3-mercaptopropionate), mercapto group amount 7.53 mmol / g) as polyfunctional thiol (B), 0.002 parts of tetraethyl thiuram disulfide (manufactured by Tokyo Chemical Industry Co., Ltd.) as reaction retarder (C), 0.4 parts of green quantum dots and 0.07 parts of red quantum dots as quantum dots (D), 5 parts of Eposter MS (manufactured by Nippon Shokubai Co., Ltd., benzoguanamine-formaldehyde condensate particles) as scattering agent (E), 0.4 parts of Irgacure 184 (manufactured by BASF) as photopolymerization initiator (F), and 1.37 parts of dispersion resin (G-6) as dispersion resin (G) were blended, and the mixture was gently shaken by hand, and then stirred with a homodisper until the whole was uniform. In the quantum dot-containing composition (X-13) thus obtained, the ratio of the number of moles of (meth)acrylate groups in the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups in the polyfunctional thiol (B) was 0.

[0139] Experimental Example 14 As the polyfunctional thiol (B), 50 parts of PEMP (manufactured by SC Organic Chemical Industry Co., Ltd., pentaerythritol tetrakis(3-mercaptopropionate), mercapto group amount 8.19 mmol / g) was used, as other compounds, 50 parts of isobornyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd., (meth)acrylate group amount 4.50 mmol / g) was used, 0.002 parts of tetraethyl thiuram disulfide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the reaction retarder (C), and 0.002 parts of tetraethyl thiuram disulfide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the reaction retarder (D). As the dots (D), 0.4 parts of green quantum dots, 0.07 parts of red quantum dots, 5 parts of Eposter MS (manufactured by Nippon Shokubai Co., Ltd., benzoguanamine-formaldehyde condensate particles) as the scattering agent (E), 0.4 parts of Irgacure 184 (manufactured by BASF) as the photopolymerization initiator (F), 1.37 parts of dispersion resin (G-6) as the dispersion resin (G) were blended, and after gently shaking by hand, the whole was stirred with a homodisper until uniform. In the quantum dot-containing composition (X-14) thus obtained, the ratio of the number of moles of (meth)acrylate groups of the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups of the polyfunctional thiol (B) was 0.

[0140] <Experimental Example 15> As polyfunctional (meth) acrylate (A), AD-TMP (manufactured by Shin-Nakamura Chemical Co., Ltd., ditrimethylolpropane tetraacrylate, acrylate group amount 8.51 mmol / g) 50 parts, as other compounds octyl thioglycolate (manufactured by Tokyo Chemical Industry Co., Ltd., mercapto group amount 4.89 mmol / g) 50 parts, as reaction retarder (C), triphenyl phosphite (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.5 parts, as quantum dots (D), 0.4 parts of green quantum dots, 0.07 parts of red quantum dots, as scattering agent (E), Eposter MS (manufactured by Nippon Shokubai Co., Ltd., benzoguanamine formaldehyde condensate particles) 5 parts, as photopolymerization initiator (F), Irgacure 184 (manufactured by BASF Corporation) 0.4 parts, as dispersion resin (G), dispersion resin (G-6) 1.37 parts were blended, and after shaking lightly by hand, the whole was stirred until uniform with a homodisper. In the quantum dot-containing composition (X-15) thus obtained, the ratio of the number of moles of (meth)acrylate groups in the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups in the polyfunctional thiol (B) was 0.43 / 0 (infinity due to division by zero).

[0141] <Experimental Example 16> As other compounds, 20 parts of triallyl isocyanurate (manufactured by Tokyo Chemical Industry Co., Ltd., allyl group amount 12.0 mmol / g), 25 parts of isobornyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd., (meth) acrylate group amount 4.50 mmol / g), 0.4 parts of green quantum dots as quantum dots (D), 0.07 parts of red quantum dots, 5 parts of Eposter MS (manufactured by Nippon Shokubai Co., Ltd., benzoguanamine-formaldehyde condensate particles) as scattering agent (E), 1 part of Irgacure TPO-L (manufactured by BASF) as photopolymerization initiator (F), and 54 parts of dispersion resin (G-3) as dispersion resin (G) were blended, and the mixture was lightly shaken by hand, and then stirred with a homodisper until the whole was uniform. In the quantum dot-containing composition (X-16) thus obtained, the ratio of the number of moles of (meth)acrylate groups in the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups in the polyfunctional thiol (B) was 0 / 0 (infinity due to division by zero).

[0142] <Experimental Example 17> As the polyfunctional (meth) acrylate (A), AD-TMP (manufactured by Shin-Nakamura Chemical Co., Ltd., ditrimethylolpropane tetraacrylate, (meth) acrylate group amount 8.51 mmol / g) 60 parts, as the polyfunctional thiol (B), PEMP (manufactured by SC Organic Chemical Co., Ltd., pentaerythritol tetrakis (3-mercaptopropionate) mercapto group amount 8.19 mmol / g) 40 parts, as quantum dots (D), 0.4 parts of green quantum dots, 0.07 parts of red quantum dots, 5 parts of Eposter MS (manufactured by Nippon Shokubai Co., Ltd., benzoguanamine formaldehyde condensate particles) as scattering agent (E), 0.4 parts of Irgacure 184 (manufactured by BASF) as photopolymerization initiator (F), 1.37 parts of dispersion resin (G-2) as dispersion resin (G) were blended, and after shaking lightly by hand, the whole was stirred uniformly with a homodisper. In the quantum dot-containing composition (X-17) thus obtained, the ratio of the number of moles of (meth)acrylate groups in the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups in the polyfunctional thiol (B) was 1.56.

[0143] <Experimental Example 18> As the polyfunctional (meth) acrylate (A), AD-TMP (manufactured by Shin-Nakamura Chemical Co., Ltd., ditrimethylolpropane tetraacrylate, (meth) acrylate group amount 8.51 mmol / g) was used as 60 parts, as the polyfunctional thiol (B), PEMP (manufactured by SC Organic Chemical Co., Ltd., pentaerythritol tetrakis (3-mercaptopropionate), mercapto group amount 8.19 mmol / g) was used as 40 parts, as the reaction retarder (C), triphenyl phosphite (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as 0.5 parts, as the quantum dots (D), 0.4 parts of green quantum dots, 0.07 parts of red quantum dots, 0.4 parts of Irgacure 184 (manufactured by BASF) was used as the photopolymerization initiator (F), and 1.37 parts of the dispersion resin (G-2) was used as the dispersion resin (G-2). After gently shaking the mixture by hand, the mixture was stirred with a homodisper until the whole was uniform. In the quantum dot-containing composition (X-18) thus obtained, the ratio of the number of moles of (meth)acrylate groups in the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups in the polyfunctional thiol (B) was 1.56.

[0144] <Experimental Example 19> As the polyfunctional (meth) acrylate (A), AD-TMP (manufactured by Shin-Nakamura Chemical Co., Ltd., ditrimethylolpropane tetraacrylate, (meth) acrylate group amount 8.51 mmol / g) 60 parts, as the polyfunctional thiol (B), PEMP (manufactured by SC Organic Chemical Co., Ltd., pentaerythritol tetrakis (3-mercaptopropionate), mercapto group amount 8.19 mmol / g) 40 parts, as the reaction retarder (C), tetraethyl thiuram disulfide (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.004 parts, as the quantum dots (D), 0.4 parts of green quantum dots, 0.07 parts of red quantum dots, as the scattering agent (E), Eposter MS (manufactured by Nippon Shokubai Co., Ltd., benzoguanamine formaldehyde condensate particles) 5 parts, as the dispersion resin (G), 1.37 parts of dispersion resin (G-2) were blended, and after shaking lightly by hand, the whole was stirred uniformly with a homodisper. In the quantum dot-containing composition (X-19) thus obtained, the ratio of the number of moles of (meth)acrylate groups in the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups in the polyfunctional thiol (B) was 1.56.

[0145] Experimental Example 20 35 parts of AD-TMP (ditrimethylolpropane tetraacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd., (meth)acrylate group amount: 8.51 mmol / g) as the polyfunctional (meth)acrylate (A), 65 parts of PEMP (pentaerythritol tetrakis(3-mercaptopropionate), mercapto group amount: 8.19 mmol / g) as the polyfunctional thiol (B), and tetraethylthiuram disulfide (manufactured by Tokyo Chemical Industry Co., Ltd.) as the reaction retarder (C). (manufactured by Nippon Shokubai Co., Ltd.) 0.004 parts, quantum dots (D) as 0.4 parts of green quantum dots, 0.07 parts of red quantum dots, scattering agent (E) as 5 parts of Eposter MS (manufactured by Nippon Shokubai Co., Ltd., benzoguanamine-formaldehyde condensate particles), photopolymerization initiator (F) as 0.4 parts of Irgacure 184 (manufactured by BASF), dispersion resin (G) as 1.37 parts of dispersion resin (G-2) were blended, and after gently shaking by hand, the whole was stirred with a homodisper until uniform. The ratio of the number of moles of (meth)acrylate groups of the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups of the polyfunctional thiol (B) of the quantum dot-containing composition (X-20) thus obtained was 0.56.

[0146] Experimental Example 21 90 parts of AD-TMP (ditrimethylolpropane tetraacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd., (meth)acrylate group amount: 8.51 mmol / g) as the polyfunctional (meth)acrylate (A), 10 parts of PEMP (pentaerythritol tetrakis(3-mercaptopropionate), mercapto group amount: 8.19 mmol / g) as the polyfunctional thiol (B), and tetraethylthiuram disulfide (manufactured by Tokyo Chemical Industry Co., Ltd.) as the reaction retarder (C). (manufactured by Nippon Shokubai Co., Ltd.) 0.004 parts, quantum dots (D), 0.4 parts green quantum dots, 0.07 parts red quantum dots, 5 parts Eposter MS (manufactured by Nippon Shokubai Co., Ltd., benzoguanamine-formaldehyde condensate particles) as scattering agent (E), 0.4 parts Irgacure 184 (manufactured by BASF) as photopolymerization initiator (F), 1.37 parts of dispersion resin (G-2) as dispersion resin (G) were blended, and after gently shaking by hand, the whole was stirred with a homodisper until uniform. The ratio of the number of moles of (meth)acrylate groups of the polyfunctional (meth)acrylate (A) to the number of moles of mercapto groups of the polyfunctional thiol (B) of the quantum dot-containing composition (X-21) thus obtained was 9.36.

[0147] <Pot Life Evaluation of Quantum Dot-Containing Composition (X)> The viscosity of the resulting quantum dot-containing compositions (X-1) to (X-21) was measured immediately after preparation. The quantum dot-containing compositions were then transferred to a lidded sample tube and allowed to stand at 25°C for 24 hours while stirring with a roller stirrer. The viscosity of the quantum dot-containing composition was then measured again. The viscosity immediately after preparation and the viscosity increase rate after 24 hours were calculated using the following formula to evaluate the pot life of each quantum dot-containing composition. Viscosity Increase Rate (%) = (Viscosity after 24 hours / Viscosity immediately after preparation) × 100 Viscosity after 24 hours (cps) Viscosity immediately after preparation (cps) The evaluation criteria are as follows: ◎: Increase rate less than 120%. Good. ◯: Increase rate 120% or more but less than 150%. Acceptable for practical use. △: Increase rate 150% or more but less than 200%. Lower limit of practical use. ×: Increase rate 200% or more or gel formation. Not practical.

[0148]

[0149]

[0150] The meanings of the abbreviations in Tables 2 and 3 are as follows: A-DCP: A-DCP (dimethylol-tricyclodecane diacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd. A-TMPT: A-TMPT (trimethylolpropane triacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd. AD-TMP: AD-TMP (ditrimethylolpropane tetraacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd. A-DPH: A-DPH (dipentaerythritol hexaacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd. UV-7650B: Shikou UV-7650B (urethane acrylate) manufactured by Nippon Synthetic Chemical Industry Co., Ltd. EGMP-4: EGMP-4 (tetraethylene glycol bis(3-mercaptopropionate)) manufactured by SC Organic Chemical Industry Co., Ltd. TMMP: TMMP (trimethylolpropane tris(3-mercaptopropionate)) manufactured by SC Organic Chemical Industry Co., Ltd. PEMP: PEMP (pentaerythritol tetrakis(3-mercaptopropionate)) manufactured by SC Organic Chemical Industries, Ltd. MT PE1: Karenz MT PE1 (pentaerythritol tetrakis(3-mercaptobutyrate)) manufactured by Showa Denko K.K. DPMP: DPMP (dipentaerythritol hexakis(3-mercaptopropionate)) manufactured by SC Organic Chemical Industries, Ltd. D-918: D-918 (rutile-type titanium oxide) manufactured by Sakai Chemical Industry Co., Ltd. MBX-5: Techpolymer MBX-5 (crosslinked polymethyl methacrylate particles) manufactured by Sekisui Plastics Co., Ltd. MS: Eposter MS (benzoguanamine-formaldehyde condensate particles) manufactured by Nippon Shokubai Co., Ltd. 2000M: Optobeads 2000M (melamine resin-silica composite particles) manufactured by Nissan Chemical Industries, Ltd. Irg184: Irgacure 184 (alkylphenone-based photopolymerization initiator), manufactured by BASF Corporation. TPO: Irgacure TPO (acylphosphine oxide-based photopolymerization initiator), manufactured by BASF Corporation. TPO-L: Irgacure TPO-L (acylphosphine oxide-based photopolymerization initiator), manufactured by BASF Corporation.

[0151] <Production of quantum dot-containing sheets> Sheet members (Y-1) to (Y-21) having a laminated structure were obtained according to the method described below using the quantum dot-containing compositions (X-1) to (X-21) of Experimental Examples 1 to 21. Tables 4 and 5 show the properties of the quantum dot-containing compositions and sheet members used in the production, as well as the results of the performance tests described below.

[0152] The quantum dot-containing compositions (X-1) to (X-21) were each applied to the primer-treated surface of a 125 μm-thick PET film (one side of which was matte-treated and the other side was primer-treated, and the film had no barrier layer) using a roll coater so that the quantum dot layer thickness was approximately 50 μm or less (preferably 2 to 30 μm), and a 125 μm-thick PET film of the same configuration was attached so that the primer-treated surface was the ink-coated surface. Then, using an ultraviolet irradiation device (120 W / cm ２ A high-pressure mercury lamp was used, with an integrated light intensity of 1000 mJ / cm ２ A curing treatment was carried out by irradiating ultraviolet rays so that the curing reaction reached a temperature of 40°C. Thereafter, the sheet was left to stand for 12 hours at 40°C to complete the curing reaction. In this way, sheet members (Y-1) to (Y-21) having a thickness of approximately 350 µm were obtained.

[0153] (Performance Test) <Evaluation of Haze Value and Total Light Transmittance> The haze value and total light transmittance of the sheet members (Y-1) to (Y-21) were measured by the above-mentioned method. <Evaluation of Luminescence Quantum Yield of Sheet Members> The luminescence quantum yield of the sheet members (Y-1) to (Y-21) was measured by the above-mentioned method. The evaluation criteria are as follows: ◎: Quantum yield of 85% or more. Good. ○: Quantum yield of 75% or more but less than 85%. Acceptable for practical use. △: Quantum yield of 65% or more but less than 75%. Lower limit for practical use. ×: Quantum yield of less than 65%. Not suitable for practical use.

[0154] <Evaluation of Adhesion> Using a 100 mm x 100 mm blade manufactured by Dumbbell Co., 10 sheets each of the sheet members (Y-1) to (Y-21) were punched out. The presence or absence of lifting or peeling at the edge of the sheet member was evaluated visually. The evaluation criteria are as follows: ⊚: 0 lifting or peeling. Good. ○: 1 lifting or peeling. Acceptable for practical use. △: 2 lifting or peeling. Lower limit for practical use. ×: 3 or more lifting or peeling. Unacceptable.

[0155] <Evaluation of Durability Over Time> Each of the sheet members (Y-1) to (Y-21) was cut into three pieces measuring 50 mm x 50 mm, and stored for 1000 hours under the following three conditions. The retention rates of the emission peak intensity of green light and red light before and after storage were calculated using the following formula: Retention rate of emission peak intensity (%) = (Emission peak intensity after 1000 hours of storage / Emission peak intensity before storage) x 100 The storage conditions over time were as follows: Condition 1: 60°C, 90% RH, blue LED lit Condition 2: 65°C, 95% RH, blue LED not lit Condition 3: 85°C, blue LED not lit The evaluation criteria for durability over time are as follows: ⊚: Retention rate of 90% or more. Good ◯: Retention rate of 75% or more but less than 90%. Acceptable for practical use △: Retention rate of 60% or more but less than 75%. Lower limit for practical use ×: Retention rate of less than 60%. Not suitable for practical use

[0156] <Evaluation of Edge Discoloration of Sheet Members> For the sheet members (Y-1) to (Y-21) stored for 1000 hours under Condition 1 in the evaluation of durability over time, the lengths of the discolored portions from the edges were measured at three points using a digital microscope (Keyence Corporation, VHS-5000), and discoloration was evaluated from the average length. The evaluation criteria are as follows: ⊚: Discolored portion is 100 μm or less. Good. ○: Discolored portion is 100 μm or more and 200 μm or less. Acceptable for practical use. △: Discolored portion is 200 μm or more and 500 μm or less. Lower limit for practical use. ×: Discolored portion is 500 μm or more. Not suitable for practical use.

[0157]

[0158]

[0159] As shown in Tables 4 and 5, in Experimental Example 33, since polyfunctional thiol (B) was not used, the oxygen barrier of the cured film was insufficient, and the durability and edge discoloration resistance were significantly deteriorated.

[0160] In Experimental Example 34, since the polyfunctional (meth)acrylate (A) was not used, the quantum dot-containing composition did not harden, the adhesive strength and oxygen barrier properties were insufficient, and the adhesion, durability, and edge discoloration were significantly deteriorated.

[0161] In Experimental Example 35, a monofunctional (meth)acrylate was used instead of the polyfunctional (meth)acrylate (A), and therefore the crosslinking density of the cured film was insufficient, sufficient oxygen barrier properties were not obtained, and durability and edge discoloration resistance were significantly deteriorated.

[0162] In Experimental Example 36, a monofunctional thiol was used instead of the polyfunctional thiol (B), and therefore the crosslink density of the cured film was insufficient, sufficient oxygen barrier properties were not obtained, and durability and edge discoloration were significantly deteriorated.

[0163] In Experimental Example 37, a monofunctional (meth)acrylate and a low-reactivity polyfunctional arylate were used instead of the polyfunctional (meth)acrylate (A), and therefore a relatively good pot life was obtained even without using the reaction retarder (C). However, the degree of crosslinking of the cured film was insufficient, and sufficient oxygen barrier properties were not obtained, resulting in significant deterioration in durability and edge discoloration.

[0164] In Experimental Example 38, since the reaction retarder (C) was not used, after uniform stirring, a significant increase in viscosity occurred within about 10 minutes, making it impossible to coat the laminate, and it was therefore not possible to evaluate the various performances of the laminate.

[0165] Experimental Example 39 is an example in which the scattering agent (E) was not used. Although excellent results were obtained in terms of durability and edge discoloration, it was found that the wavelength of the excitation light was not converted by the quantum dots (D), making it difficult to select a sufficient optical path length.

[0166] Experimental Example 40 is an example in which the photopolymerization initiator (F) was not used. In this example, the crosslinking reaction hardly progressed upon ultraviolet irradiation, resulting in delamination, making it impossible to evaluate the various performances of the laminate. For this reason, it is necessary to use the photopolymerization initiator (F) or to use an additive in place of the photopolymerization initiator (F).

[0167] In Experimental Examples 41 and 42, the ratio of the number of moles of (meth)acrylate groups in the polyfunctional (meth)acrylate to the number of moles of mercapto groups in the polyfunctional thiol was either too small or too large, resulting in insufficient crosslinking density, insufficient oxygen barrier properties, and a tendency toward deterioration in durability and edge discoloration.

[0168] On the other hand, Examples 22 to 32 are sheet members made using quantum dot-containing compositions containing polyfunctional (meth)acrylate (A), polyfunctional thiol (B), reaction retarder (C), scattering agent (D), photopolymerization initiator (E), and quantum dot emitter (F) in suitable ranges, and the haze value, total light transmittance, luminescence quantum yield of the laminate, adhesion, durability, and edge fading were well balanced. Among the above experimental examples, Experimental Examples 29 to 32 showed excellent performance.

[0169] In Experimental Examples 29 to 32, the average number of functional groups per molecule of the polyfunctional (meth)acrylate (A) and the polyfunctional thiol (B) was within the preferred range of 2.5 or more, and therefore sufficient crosslinking density of the cured film was obtained, and excellent durability and edge discoloration resistance were obtained compared to Experimental Example 1, which was outside the range. Experimental Examples 29 to 32, which used dispersant (G), therefore, showed superior luminescence quantum yield compared to Experimental Example 23, which did not use dispersant (G).

[0170] In Experimental Examples 29 to 32, fine particles having a melamine and / or benzoguanamine structure were used as a scattering agent, and therefore superior luminescence quantum yields were obtained compared to Experimental Examples 24 and 28, in which no scattering agent was used.

[0171] In Experimental Examples 29 to 32, the ratio of the number of moles of (meth)acrylate groups in the polyfunctional (meth)acrylate to the number of moles of mercapto groups in the polyfunctional thiol was in the more preferable range of 1.0 to 2.5, and therefore sufficient crosslinking density of the cured film was obtained, and excellent durability and edge discoloration resistance were obtained compared to Experimental Examples 25 and 26, which were outside the range.

[0172] In Experimental Examples 29 to 32, the dispersant (G) used was at least one selected from an acrylic resin, a polyurethane resin, a polyester resin, and a polyethyleneimine resin. Therefore, the compatibility of the quantum dots (D) was improved compared to Experimental Example 27, which used a thioether resin, and an excellent luminescence quantum yield was obtained.

[0173] In this example, the deterioration could be suppressed to 500 μm or less from the edge of the sheet, preferably 250 μm or less, more preferably 150 μm or less, and most preferably 50 μm or less.

[0174] <Brightness experiment with and without partial reflection sheet (dichroic filter)> The following samples were used in the experiment: (Sample 1) Direct BL (blue light) + QD sheet + prism (Sample 2) Direct BL (blue light) + QD-coated dichroic filter + prism (Sample 3) Direct BL (blue light) + dichroic filter + QD sheet + prism (Sample 4) Direct BL (blue light) + QD sheet + prism + DBEF (Sample 5) Direct BL (blue light) + QD-coated dichroic filter + prism + DBEF (Sample 6) Direct BL (blue light) + dichroic filter + QD sheet + prism + DBEF

[0175] The QD sheet contains quantum dots that emit red and green light. The QD-coated dichroic filter is a dichroic filter whose surface is coated with a QD solution containing quantum dots that emit red and green light to form a QD layer. DBEF is a reflective polarizing film (Dual Brightness Enhancement Film) manufactured by 3M.

[0176] In the experiment, the relationship between wavelength and luminance (emission intensity) was measured for samples divided into two groups: Samples 1 to 3 and Samples 4 to 6. The emission intensity was measured using a spectrofluorometer (FP-8500, manufactured by JASCO Corporation).

[0177] Fig. 14 is a graph showing the relationship between wavelengths of 400 nm to 700 nm and emission intensity for Samples 1 to 3. Fig. 15 is a graph showing the relationship between wavelengths of 400 nm to 700 nm and emission intensity for Samples 4 to 6. Fig. 16 is a graph showing the relationship between wavelengths of 500 nm to 700 nm and emission intensity for Samples 1 to 3. Fig. 17 is a graph showing the relationship between wavelengths of 500 nm to 700 nm and emission intensity for Samples 4 to 6.

[0178] 14 and 15, Sample 1 and Sample 4, which do not have a partial reflection sheet, showed high blue emission intensity. In contrast, Samples 2, 3, 5, and 6, which have a partial reflection sheet, were able to suppress the blue emission intensity. In particular, in this example, I-III-VI type chalcopyrite, which has a higher absorption coefficient at 450 m than InP, was used as the quantum dots, and therefore the blue emission intensity could be more effectively weakened.

[0179] Furthermore, as shown in Figures 16 and 17, in Samples 1 and 4, which do not have a partial reflective sheet, the red luminescence intensity and green luminescence intensity decreased, while in comparison, in Samples 2, 3, 5, and 6, which have a partial reflective sheet, the red luminescence intensity and green luminescence intensity were able to be increased.

[0180] (Sample 7: see Figure 22) Direct BL (blue light) + QD sheet + prism (Sample 8: see Figure 23) Direct BL (blue light) + dichroic filter + QD sheet + prism + DBEF (Sample 9: see Figure 24) Direct BL (blue light) + (dichroic filter + QD sheet) composite sheet + prism + DBEF (Sample 10: see Figure 25) Direct BL (blue light) + QD sheet + prism + DBEF (Sample 11: see Figure 26) Direct BL (blue light) + (dichroic filter + QD sheet + prism) composite sheet + DBEF (Sample 12: see Figure 27) Direct BL (blue light) + (dichroic filter + QD sheet + prism + DBEF) composite sheet

[0181] Fig. 18 is a graph showing the relationship between wavelengths of 400 nm to 700 nm and emission intensity for Samples 7 to 9. Fig. 19 is a graph showing the relationship between wavelengths of 400 nm to 700 nm and emission intensity for Samples 7 to 9. Fig. 20 is a graph showing the relationship between wavelengths of 500 nm to 700 nm and emission intensity for Samples 7 to 9. Fig. 21 is a graph showing the relationship between wavelengths of 500 nm to 700 nm and emission intensity for Samples 10 to 12. Note that in Figs. 20 and 21, the range of emission intensity on the vertical axis is expanded compared to Figs. 18 and 19.

[0182] As shown in Figures 18 and 19, Samples 7 and 10, which do not have a partial reflective sheet, had high blue luminescence intensity, while Samples 8, 9, 11, and 12, which had a partial reflective sheet, were able to suppress the blue luminescence intensity.

[0183] Furthermore, as shown in Figures 20 and 21, in Samples 7 and 10, which do not have a partial reflective sheet, the red luminescence intensity and green luminescence intensity decreased, while in comparison, in Samples 8, 9, 11, and 12, which have a partial reflective sheet, the red luminescence intensity and green luminescence intensity were able to be increased.

[0184] As described above, it has been found that by using a partially reflective sheet, it is possible to increase the red and green emission intensities while suppressing the blue emission intensity, thereby increasing the brightness of the white light emitted by wavelength-converting the light from the blue LED and suppressing brightness unevenness.

[0185] In this example, in particular, since I-III-VI type chalcopyrite, which has an absorption coefficient 450 m higher than that of InP, is used as the quantum dot, it was possible to more effectively weaken the blue emission intensity and increase the OD (Optical Density) value.

[0186] <Sheet Thickness Experimental Results> In the experiment, a quantum dot-containing sheet containing 40% green quantum dots, 15% dispersant, and the remainder transparent resin was formed to a sheet thickness of 10 μm and placed in a blue backlight (Example 1). Also, a quantum dot-containing sheet containing 30% red quantum dots, 5% dispersant, and the remainder transparent resin was formed to a sheet thickness of 10 μm and placed in a blue backlight (Example 2).

[0187] 28A shows the emission spectrum of the backlight, FIG. 28B shows the emission spectrum of Example 1, and FIG. 28C shows the emission spectrum of Example 2.

[0188] The ratio of the blue wavelength emission intensity to the peak intensity of the backlight in Example 1 was 1.2%, and the ratio of the blue wavelength emission intensity to the peak intensity of the backlight in Example 2 was 10.3%. As described above, the leakage of blue light was successfully suppressed in both Examples 1 and 2, but the effect was particularly pronounced in Example 1, which was a green quantum dot-containing sheet.

[0189] Furthermore, the peak intensity ratio of Example 1 shown in FIG. 28B to the peak intensity of the backlight in FIG. 28A was approximately 246.3%, and the peak intensity ratio of Example 2 shown in FIG. 28C to the peak intensity of the backlight in FIG. 28A was approximately 61.4%. Color conversion was performed efficiently in both cases, but the effect was particularly noticeable in Example 1, the green quantum dot-containing sheet.

[0190] <Experiment on Deterioration from the Sheet Edges> Fig. 29 shows the results of an experiment in which the quantum dot-containing sheet of Example 1 was used in an RA lighting test at a temperature of 60% and a humidity of 90%, and the deterioration mode was confirmed from 0 to 1000 hours. The upper row of Fig. 29 shows photographs, and the lower row of Fig. 29 shows a schematic diagram. After about 1000 hours, the edges became somewhat darker, and deterioration of about 150 μm was observed, but it was found that the deterioration could be suppressed to 500 μm or less.

[0191] The QD sheet of this example can be effectively applied to display methods, and is preferably applied to the MiNiLED shown in Figure 30, for example. However, the QD sheet of this example has a high absorption coefficient and is also effective for the QD OLED and μLED shown in Figure 30.

[0192] In order to obtain the same absorption coefficient as in this example using InP as a comparative example, the sheet thickness must be increased. In particular, in the case of the green quantum dots shown in FIG. 13A, in order to obtain a similar absorption coefficient and high emission intensity in InP, the sheet thickness must be approximately six times thicker. Therefore, InP cannot be applied to QD OLEDs and μLEDs, which require particularly thin films. However, in this example, high emission intensity can be obtained even with a sheet thickness of 50 μm or less, preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less (see the experimental results in FIGS. 13A, 13B, 28B, and 28C).

[0193] The present invention provides quantum dots that can reduce the quantum dot layer thickness to 50 μm or less and enable a sheet to be obtained that has excellent durability over time from the sheet edge, as well as a quantum dot-containing sheet, backlight device, or display device that uses the quantum dots.The quantum dot-containing sheet of the present invention can be used to realize backlight devices, display devices, liquid crystal display elements, etc. that have stable wavelength conversion characteristics.

[0194] This application is based on Japanese Patent Application No. 2023-170553, filed on September 29, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. Quantum dots that do not contain RoHS restricted substances and have a higher absorption coefficient at 450 nm than InP.

2. The quantum dot according to claim 1, characterized in that the quantum dot comprises a core made of a I-III-VI type chalcopyrite system.

3. A quantum dot according to claim 2, characterized in that group I includes at least one of Ag or Cu, group III includes at least one of Ga or In, and group VI includes at least one of S, Se, and Te.

4. The quantum dot according to claim 1, characterized in that it contains Ga and Zn, and the ratio of Zn to Ga is Zn / Ga = 0.1 or more and 10 or less.

5. The quantum dot described in claim 1, characterized in that the quantum dot is composed of a core, a shell layer formed on the surface of the core via a buffer layer, and ligands formed on the surface of the shell layer, and the shell layer is formed of ZnS.

6. A quantum dot-containing sheet obtained by curing a quantum dot-containing composition containing the quantum dots according to claim 1, characterized in that the quantum dot layer has a thickness of 50 μm or less.

7. The quantum dot-containing sheet according to claim 6, characterized in that the deterioration from the edge of the sheet is 500 μm or less.

8. The quantum dot-containing sheet according to claim 6, characterized in that the sheet is an integrated sheet with a dichroic filter or a prism sheet.

9. A backlight device or a display device, comprising the quantum dot-containing sheet according to claim 6 and configured with a narrow frame.

10. A display device, characterized in that the quantum dot-containing sheet is applied to a QD OLED or a μLED.

11. A method for producing a quantum dot-containing sheet according to claim 6, comprising the steps of: producing a quantum dot-containing composition containing the quantum dots; and curing the quantum dot-containing composition to obtain the quantum dot-containing sheet, wherein the quantum dot-containing composition contains the quantum dots, a polyfunctional (meth)acrylate, a polyfunctional thiol, and a reaction retarder.

12. The method for producing a quantum dot-containing sheet according to claim 11, characterized in that at least one of a phosphorous acid compound and a dithiocarbamate compound is selected as the reaction retarder.

13. The method for producing a quantum dot-containing sheet according to claim 11, wherein the reaction retarder is a dithiocarbamate compound.

14. The method for producing a quantum dot-containing sheet according to claim 11, further comprising the step of selecting a scattering agent having at least one of a melamine structure and a benzoguanamine structure as the scattering agent.

15. A method for producing a quantum dot-containing sheet as described in claim 11, further comprising a dispersing resin, the dispersing resin being at least one selected from the group consisting of acrylic resins, polyurethane resins, polyester resins, and polyethyleneimine resins.

16. The method for producing a quantum dot-containing sheet according to claim 11, characterized in that the average number of functional groups per molecule of the multifunctional (meth)acrylate and the multifunctional thiol is 2.5 or more.

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