JP2017214486A - Light wavelength conversion composition, light wavelength conversion particle, light wavelength conversion member, light wavelength conversion sheet, backlight device, and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light wavelength conversion composition having excellent heat resistance and moisture heat resistance after curing, a light wavelength conversion particle, a light wavelength conversion member and a light wavelength conversion sheet having excellent heat resistance and moisture heat resistance, and a backlight device and an image conversion device equipped with such a light wavelength conversion member or a wavelength conversion sheet.SOLUTION: A light wavelength conversion composition includes a quantum dot, a compound including a heterocyclic group containing an oxygen atom, and a thiol compound .SELECTED DRAWING: Figure 2

Description

  The present invention relates to a light wavelength conversion composition, a light wavelength conversion particle, a light wavelength conversion member, a light wavelength conversion sheet, a backlight device, and an image display device.

  2. Description of the Related Art A transmissive image display device such as a liquid crystal display device generally includes a backlight device that is disposed on the back side of a transmissive image display panel such as a liquid crystal display panel and illuminates the transmissive image display panel.

  Currently, in order to improve color reproducibility, it has been studied to incorporate a light wavelength conversion member including quantum dots into an image display device (see, for example, Patent Document 1). Quantum dots can absorb light (primary light) and emit light of different wavelengths (secondary light). The wavelength of light emitted from the quantum dot mainly depends on the particle diameter of the quantum dot. Therefore, in an image display device incorporating a light wavelength conversion member, various colors can be reproduced while using a light source that projects light in a single wavelength region. For example, when a light source that emits blue light is used, the light wavelength conversion member can absorb blue light and emit green light and red light. Since an image display device incorporating such a light wavelength conversion member has excellent color purity, it has excellent color reproducibility.

  In the light wavelength conversion member, the quantum dots are deteriorated by moisture or oxygen, and the light emission efficiency may be reduced. For this reason, in an optical wavelength conversion sheet which is one form of an optical wavelength conversion member and includes an optical wavelength conversion layer including quantum dots, a barrier for suppressing the transmission of moisture and oxygen on both surfaces of the optical wavelength conversion layer A film is provided. Since the barrier film is provided so as to sandwich the light wavelength conversion layer, the conventional light wavelength conversion sheet has a structure in which a barrier film, a light wavelength conversion layer, and a barrier film are laminated in this order.

JP 2015-1111518 A

  However, a heat wavelength test in which a barrier film is provided on both sides of the light wavelength conversion layer and left in an environment of 80 ° C. for 500 hours or in an environment of 60 ° C. and 90% relative humidity for 500 hours. When the moisture and heat resistance test is performed, the quantum dot deteriorates at the peripheral portion of the light wavelength conversion sheet or the point-like defects such as pinholes and cracks in the barrier film, and the luminance is lowered. is there.

  In addition, in the light wavelength conversion member in a form other than the light wavelength conversion sheet, the light wavelength conversion member may be disposed at a position close to the light source or the light source. It has been demanded.

  The present invention has been made to solve the above problems. That is, a light wavelength conversion composition having excellent heat resistance and heat and moisture resistance after curing, light wavelength conversion particles having excellent heat resistance and heat and moisture resistance, a light wavelength conversion member, and a light wavelength conversion sheet, such light wavelength conversion An object of the present invention is to provide a backlight device and an image conversion device provided with a member and a light wavelength conversion sheet.

  As a result of intensive research on the above problems, the present inventors have found that when a compound having a heterocyclic group containing an oxygen atom and a cured product of a thiol compound are used as a binder resin, light wavelength conversion particles and light wavelength conversion are used. It has been found that excellent heat resistance and moist heat resistance can be obtained in layers and the like. The present invention has been completed based on such findings.

  According to one aspect of the present invention, there is provided a light wavelength conversion composition comprising a quantum dot, a compound having a heterocyclic group containing an oxygen atom, and a thiol compound. Things are provided.

  According to another aspect of the present invention, the resin composition includes quantum dot-containing resin particles including a binder resin and quantum dots encapsulated in the binder resin, wherein the quantum dot-containing resin particles are the light wavelength conversion composition described above. The light wavelength conversion particle | grains which are the hardened | cured material of this are provided.

  According to the other aspect of this invention, the light wavelength conversion member containing the light wavelength conversion layer which consists of hardened | cured material of said light wavelength conversion composition, or said light wavelength conversion particle is provided.

  According to the other aspect of this invention, it is a light wavelength conversion sheet | seat, Comprising: The light wavelength conversion layer which consists of hardened | cured material of said light wavelength conversion composition, or the light wavelength conversion layer containing said light wavelength conversion particle | grains is provided. A light wavelength conversion sheet is provided.

  According to the other aspect of this invention, a backlight apparatus provided with a light source and said light wavelength conversion member or said light wavelength conversion sheet which receives the light from the said light source is provided.

  According to another aspect of the present invention, there is provided an image display device comprising the light wavelength conversion member, the light wavelength conversion sheet, or the backlight device.

  According to one aspect of the present invention, since a compound having a heterocyclic group containing an oxygen atom and a thiol compound are used, an optical wavelength conversion composition having excellent heat resistance and moist heat resistance after curing is provided. be able to. According to another aspect of the present invention, a light wavelength conversion particle, a light wavelength conversion member, and a light wavelength conversion sheet having excellent heat resistance and heat and moisture resistance, such a light wavelength conversion member or a light wavelength conversion sheet are provided. A backlight device and an image display device can be provided.

It is a schematic block diagram of the light wavelength conversion particle which concerns on embodiment. It is a schematic block diagram of the light wavelength conversion sheet which concerns on embodiment. It is a figure which shows the effect | action of the light wavelength conversion sheet which concerns on embodiment. It is a schematic block diagram of the other light wavelength conversion sheet which concerns on embodiment. It is a schematic block diagram of the other light wavelength conversion sheet which concerns on embodiment. It is a schematic block diagram of the other light wavelength conversion sheet which concerns on embodiment. It is a schematic block diagram of the other light wavelength conversion sheet which concerns on embodiment. It is sectional drawing along the II line of the light wavelength conversion sheet | seat of FIG. It is a schematic block diagram of the other light wavelength conversion sheet which concerns on embodiment. It is a schematic block diagram of the other light wavelength conversion sheet which concerns on embodiment. It is a figure which shows typically the manufacturing process of the light wavelength conversion sheet which concerns on embodiment. It is a figure which shows typically the manufacturing process of the light wavelength conversion sheet which concerns on embodiment. 1 is a schematic configuration diagram of an image display device including a backlight device according to an embodiment. FIG. 14 is a perspective view of the lens sheet shown in FIG. 13. It is sectional drawing along the II-II line of the lens sheet of FIG. It is a schematic block diagram of the other backlight apparatus which concerns on embodiment. It is a schematic block diagram of the other backlight apparatus which concerns on embodiment. It is a schematic block diagram of the light source shown by FIG. It is a schematic block diagram of the other backlight apparatus which concerns on embodiment. FIG. 20 is an enlarged view near the light incident surface of the optical plate shown in FIG. 19. It is a schematic block diagram of the other image display apparatus which concerns on embodiment. FIG. 22 is an enlarged view near the color filter shown in FIG. 21.

  Hereinafter, a light wavelength conversion composition, a light wavelength conversion particle, a light wavelength conversion member, a light wavelength conversion sheet, a backlight device, and an image display device according to embodiments of the present invention will be described with reference to the drawings. In this specification, terms such as “sheet” and “film” are not distinguished from each other only based on the difference in designation. Thus, for example, “sheet” is used to include a member that may also be referred to as a film, and “film” is used to include a member that may also be referred to as a sheet. FIG. 1 is a schematic configuration diagram of a light wavelength conversion particle according to this embodiment, FIG. 2 is a schematic configuration diagram of a light wavelength conversion sheet according to this embodiment, and FIG. 3 is a light wavelength conversion sheet according to this embodiment. 4 to 7, 9, and 10 are schematic configuration diagrams of another light wavelength conversion sheet according to the present embodiment, and FIG. 8 is a diagram of the light wavelength conversion sheet I in FIG. 7. FIG. 11 is a cross-sectional view taken along line −I, and FIGS. 11 and 12 are diagrams schematically illustrating a manufacturing process of the optical wavelength conversion sheet according to the present embodiment.

<<< Light wavelength conversion composition >>>
The light wavelength conversion composition contains quantum dots, a compound having a heterocyclic group containing an oxygen atom, and a thiol compound. The compound having a heterocyclic group and the thiol compound become a binder resin after curing. The light wavelength conversion composition may further contain a curing agent. The light wavelength conversion composition preferably contains light diffusing particles.

  When forming a light wavelength conversion layer using a light wavelength conversion composition, it is preferable that the viscosity of a light wavelength conversion composition is 10 mPa * s or more and 10,000 mPa * s or less. When the viscosity of the light wavelength conversion composition is less than 10 mPa · s, it may be difficult to form a sufficient film thickness. When the viscosity exceeds 10,000 mPa · s, the light wavelength conversion composition may be applied. Coating may be difficult and leveling properties may be deteriorated. The lower limit of the viscosity of the light wavelength conversion composition is preferably 10 mPa · s or more, and the upper limit of the viscosity of the light wavelength conversion composition is preferably 10,000 mPa · s or less.

<< Quantum dots >>
Quantum dots are nano-sized semiconductor particles having a quantum confinement effect. The particle diameter and average particle diameter of the quantum dots are, for example, 1 nm or more and 20 nm or less. When the quantum dot absorbs light from the excitation source and reaches an energy excited state, the quantum dot emits energy corresponding to the energy band gap of the quantum dot. Therefore, by adjusting the particle size of the quantum dots or the composition of the substance, the energy band gap can be adjusted, and energy in various levels of wavelength bands can be obtained. In particular, quantum dots can generate strong fluorescence in a narrow wavelength band.

  Specifically, the energy band gap of the quantum dot increases as the particle size decreases. That is, as the crystal size decreases, the light emission of the quantum dots shifts to the blue side, that is, to the high energy side. Therefore, by changing the particle diameter of the quantum dots, the emission wavelength can be adjusted over the entire wavelength range of the ultraviolet region, the visible region, and the infrared region. For example, when the quantum dot is composed of CdSe / ZnS described later, blue light is emitted when the particle diameter of the quantum dot is 2.0 nm or more and 4.0 nm or less, and the particle diameter of the quantum dot is 3.0 nm. When it is 6.0 nm or less, green light is emitted, and when the particle size of the quantum dots is 4.5 nm or more and 10.0 nm or less, red light is emitted. In the above, the particle diameter range of the quantum dot emitting blue light and the particle diameter range of the quantum dot emitting green light partially overlap, and the particle diameter of the quantum dot emitting green light and the red light Although the range of the particle diameter of the emitted quantum dots partially overlaps, even if the quantum dots have the same particle diameter, the emission color may vary depending on the size of the quantum dot core, so there is no contradiction. Not what you want. The average particle diameter of the quantum dots is obtained by measuring the particle diameter of 20 quantum dots in the cross-sectional observation of the light wavelength conversion particles using a transmission electron microscope or a scanning transmission electron microscope, and calculating the average value. .

  As the quantum dot, one kind of quantum dot may be used, but it is also possible to use two or more kinds of quantum dots each having an emission band in a single wavelength region by different particle diameters or materials. . The quantum dot may include a first quantum dot and a second quantum dot having a light emission band in a wavelength region different from that of the first quantum dot.

  Quantum dots can generate strong fluorescence in a desired narrow wavelength range. For this reason, the backlight device using the light wavelength conversion sheet can illuminate the display panel with light of three primary colors having excellent color purity. In this case, the display panel has excellent color reproducibility.

  The quantum dot is composed of, for example, a core made of a first semiconductor compound, a shell made of a second semiconductor compound that covers the core and is different from the first semiconductor compound, and a ligand bonded to the surface of the shell. Has been.

  Examples of the first semiconductor compound constituting the core include MgS, MgSe, MgTe, CaS, CaSe, CaTe, SrS, SrSe, SrTe, BaS, BaSe, BaTe, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, II-VI semiconductor compounds such as HgS, HgSe and HgTe, III such as AlN, AlP, AlAs, AlSb, GaAs, GaP, GaN, GaSb, InN, InAs, InP, InSb, TiN, TiP, TiAs and TiSb A semiconductor crystal containing a semiconductor compound or a semiconductor such as a group V semiconductor compound, a group IV semiconductor such as Si, Ge, and Pb can be given. Alternatively, a semiconductor crystal including a semiconductor compound containing three or more elements such as InGaP can be used. Among these, semiconductor crystals such as CdS, CdSe, CdTe, InP, and InGaP are preferable from the viewpoints of ease of production and controllability of particle diameters that can obtain light emission in the visible range.

  As the second semiconductor compound constituting the shell, a semiconductor compound having a band gap higher than that of the first semiconductor compound constituting the core is preferably used so that excitons are confined in the core. Thereby, the luminous efficiency of a quantum dot can be improved. Examples of the second semiconductor compound constituting the shell include ZnS, ZnSe, CdS, GaN, CdSSe, ZnSeTe, AlP, ZnSTe, and ZnSSe.

  As a specific combination of the core-shell structure (core / shell) composed of a core and a shell, for example, CdSe / ZnS, CdSe / ZnSe, CdSe / CdS, CdTe / CdS, InP / ZnS, Gap / ZnS, Si / ZnS, Examples include InN / GaN, InP / CdSSe, InP / ZnSeTe, InGaP / ZnSe, InGaP / ZnS, Si / AlP, InP / ZnSTe, InP / ZnSSe, InGaP / ZnSTe, and InGaP / ZnSSe.

  The ligand is for stabilizing unstable quantum dots. Examples of the ligand include sulfur compounds such as thiols, phosphorus compounds such as phosphine compounds or phosphine oxides, nitrogen compounds such as amines, and carboxyl group-containing compounds.

  The shape of the quantum dot is not particularly limited, and may be, for example, a spherical shape, a rod shape, a disk shape, or other shapes. The particle diameter of the quantum dots can be a true spherical value having the same volume when the shape of the quantum dots is not spherical.

  Information such as the particle diameter, average particle diameter, shape, and dispersion state of the quantum dots can be obtained by a transmission electron microscope or a scanning transmission electron microscope. In addition, since the emission color of the quantum dot changes depending on the particle diameter, the particle diameter of the quantum dot can be obtained from confirmation of the emission color of the quantum dot. In addition, the crystal structure and crystallite size of the quantum dots can be known by X-ray crystal diffraction (XRD). Furthermore, the information regarding the particle diameter etc. of a quantum dot can also be obtained with an ultraviolet-visible (UV-Vis) absorption spectrum.

  The content of quantum dots in the light wavelength conversion composition is preferably 0.01% by mass or more and 2% by mass or less, and more preferably 0.03% by mass or more and 1% by mass or less. If the content of quantum dots is less than 0.01% by mass, sufficient emission intensity may not be obtained. If the content of quantum dots exceeds 2% by mass, sufficient transmitted light of excitation light is transmitted. There is a risk that strength cannot be obtained.

<< Compound having a heterocyclic group containing an oxygen atom >>
The compound having a heterocyclic group has a heterocyclic group containing an oxygen atom. One or more oxygen atoms may be contained in the heterocyclic group, and two or more oxygen atoms may be contained. Moreover, the heterocyclic group should just be contained 1 or more in 1 molecule.

  Examples of the heterocyclic group include a cyclic ether group (epoxy group, oxetanyl group, oxacyclopentyl group, 3,4-epoxycyclohexyl group, oxolanyl group, etc.), cyclic acetal group (1,3-dioxolanyl group, 1,3 , 5-trioxanyl group, 1,3-dioxepanyl group, 1,3,6-trioxacyclooctanyl group and the like) and cyclic imino ether group (for example, oxazoline group and the like). Among these, a cyclic ether group is preferable from the viewpoint of easy reactivity, and an epoxy group exhibiting high reactivity is preferable among the cyclic ether groups.

  Although it does not specifically limit as a compound which has an epoxy group, For example, bisphenol A type epoxy compound, bisphenol F type epoxy compound, bisphenol S type epoxy compound, biphenyl type epoxy compound, fluorene type epoxy compound, novolak phenol type epoxy compound, cresol Novolak type epoxy compounds, aromatics such as modified products thereof, or alkylene glycol diglycidyl ethers such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether or 1,6-hexanediol diglycidyl ether, glycerin or alkylene thereof Polyglycidyl ether of polyhydric alcohol such as di- or triglycidyl ether of oxide adduct, polyethylene glycol or its alcohol Diglycidyl ether of sharp emission oxide adducts, polypropylene glycol or polyalkylene glycol diglycidyl ether diglycidyl ether of alkylene oxide adduct thereof, and aliphatic, such as alkylene oxide. Here, as the alkylene oxide, aliphatic epoxy compounds such as ethylene oxide and propylene oxide, 3 ′, 4′-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 3,4-epoxycyclohexylmethyl methacrylate and the like Examples thereof include alicyclic epoxy compounds containing one or more epoxy groups and one or more ester groups in the molecule.

  Examples of the compound having a heterocyclic group other than an epoxy group include (3-ethyloxetane-3-yl) methyl acrylate, (3-ethyloxetane-3-yl) methyl methacrylate, (2-methyl-2-ethyl- 1,3-dioxolan-4-yl) methyl acrylate, 2,2-bis (2-oxolanyl) propane, 2,4,4-trimethyl-2-oxazoline, 4- (4-oxanyl) -3-butene-2 -ON etc. are mentioned.

  The weight average molecular weight of the compound having a heterocyclic group is preferably 100 or more and 10,000 or less because viscosity is appropriate and processing is easy. In this specification, the “weight average molecular weight” is a value obtained by dissolving in a solvent such as tetrahydrofuran (THF) and converting to polystyrene by a conventionally known gel permeation chromatography (GPC) method. The lower limit of the weight average molecular weight of the compound having a heterocyclic group is more preferably 200 or more, and the upper limit is more preferably 2000 or less.

  Whether or not the compound having the heterocyclic group is contained in the light wavelength conversion composition is (1) infrared spectroscopic analysis (IR), (2) gas chromatography analysis (GCMS), (3) gel permeation This can be confirmed by using a combination of chromatographic analysis (GPC) and nuclear magnetic resonance spectroscopy (NMR spectroscopy). Specifically, in infrared spectroscopic analysis, the compounds contained in the light wavelength conversion composition can be roughly specified, and in gas chromatography analysis, the molecular weight of the compound contained in the light wavelength conversion composition can be specified. In permeation chromatography analysis, compounds contained in the light wavelength conversion composition can be separated, and in nuclear magnetic resonance spectroscopy, the structural formula of the compound contained in the light wavelength conversion composition can be specified. By using it, it can be confirmed whether the compound which has the said heterocyclic group is contained in the light wavelength conversion composition.

  The content of the compound having a heterocyclic group in the light wavelength conversion composition is preferably 5% by mass or more and 80% by mass or less. When the content of the compound having a heterocyclic group is less than 5% by mass, the light wavelength conversion composition is hardly cured, and when the content of the compound having a heterocyclic group exceeds 80% by mass, a cured product is obtained. Becomes difficult to process, and the content of the thiol compound decreases, so that there is a possibility that sufficient durability cannot be obtained. The content of the compound having a heterocyclic group can be confirmed by the following method. Specifically, for example, the compound having the heterocyclic group contained in the light wavelength conversion composition is identified (identified) by nuclear magnetic resonance spectroscopy, and then gas chromatography corresponding to the compound having the heterocyclic group is identified. From the peak area ratio obtained by graphic analysis or gel permeation chromatography analysis, the content of the compound having the heterocyclic group in the light wavelength conversion composition can be determined. When a plurality of compounds having the heterocyclic group are used, the content means the total content of the compounds having a plurality of types of the heterocyclic group. The lower limit of the content of the compound having a heterocyclic group in the light wavelength conversion composition is more preferably 10% by mass or more, and the upper limit is more preferably 60% by mass or less.

<< thiol compound >>
A thiol compound is a compound containing a thiol group. The compound having a heterocyclic group and the thiol compound are bonded by reacting with heat or ionizing radiation as described later. The sulfur component can be fixed in the binder resin by bonding the compound having the heterocyclic group and the thiol compound.

  Although the thiol compound should just have 1 or more thiol groups in 1 molecule, it is preferable to have 2 or more thiol groups in 1 molecule from the following viewpoints. That is, the thiol compound undergoes an addition reaction with the compound having the above heterocyclic group by heat or ionizing radiation, and is thioetherified after the reaction (after curing), but the reaction product should have an unreacted thiol group. It is preferable because it has a high function of protecting quantum dots from deterioration. In the thiol compound, when there are two or more thiol groups in one molecule, unreacted thiol groups are likely to exist in the reaction product, so the thiol compound has two or more thiol groups in one molecule. It is preferable to have.

  As the thiol compound, a primary thiol compound is particularly preferable because it is excellent in curability by heat and ionizing radiation, but a secondary thiol compound or a tertiary thiol compound may be used. When a secondary thiol compound or a tertiary thiol compound is used, the pot life at the time of coating is long, and odor can be suppressed.

  The primary thiol compound means a compound in which one hydrocarbon group is bonded to the carbon to which the thiol group is bonded, and the secondary thiol compound means two carbonized carbons to the carbon to which the thiol group is bonded. A compound in which a hydrogen group is bonded is meant, and a tertiary thiol compound means a compound in which three hydrocarbon groups are bonded to carbon to which a thiol group is bonded.

式中、Ｒ^１は水素原子、置換されていてもよい炭素原子数１〜１０のアルキル基であり、Ｒ^２は置換されていてもよい炭素原子数１〜１０のアルキレン基であり、Ｒ^３は炭素原子以外の原子を含んでいてもよい炭素原子数１〜１５のｎ価の脂肪族基であり、ｍは１〜２０の整数であり、ｎは１〜３０の整数である。 Although it does not specifically limit as a thiol compound, The compound shown by following General formula (1) from the viewpoint of the sclerosis | hardenability in the case of formation of a light wavelength conversion layer, the heat resistance of a quantum dot, and heat-and-moisture resistance improvement is preferable.

In the formula, R ¹ is a hydrogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, R ² is an optionally substituted alkylene group having 1 to 10 carbon atoms, and R ³ Is an n-valent aliphatic group having 1 to 15 carbon atoms which may contain atoms other than carbon atoms, m is an integer of 1 to 20, and n is an integer of 1 to 30.

The alkyl group for R ¹ may be linear or branched. Examples of the alkyl group for R ¹ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, n-pentyl group, neopentyl group, tert-pentyl group, isopentyl group, 2-methylbutyl group, 1-ethylpropyl group, hexyl group, isohexyl group, 4-methylpentyl group, 3-methylpentyl group, 2-methylpentyl group, 1-methylpentyl group, 3 , 3-dimethylbutyl group, 2,2-dimethylbutyl group, 1,1-dimethylbutyl group, 1,2-dimethylbutyl group, 1,3-dimethylbutyl group, 2,3-dimethylbutyl group, 1-ethylbutyl Group, 2-ethylbutyl group, heptyl group, octyl group, nonyl group, decyl group and the like.

The alkylene group for R ² may be linear or branched. Examples of the alkylene group for R ² include a methylene group, an ethylene group, a trimethylene group, a propylene group, and an isopropylidene group.

When the alkyl group of R ¹ or the alkylene group of R ² is substituted, examples of the substituent include a halogen atom, a hydroxyl group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, a carboxyl group, and a phenyl group. Examples include selected groups. Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom.

One methylene group or two or more non-adjacent methylene groups in the alkyl group of R ¹ or the alkylene group of R ² are —O—, —S—, —SO ₂ —, —CO—, —COO—, — It may be substituted with at least one group selected from the group consisting of OCO—, —NR ⁴ —, —CONR ⁴ —, —NR ⁴ CO—, —N═CH— and —CH═CH— (formula In the formula, each R ⁴ independently represents hydrogen or an alkyl group having 1 to 5 carbon atoms.)

Examples of atoms other than carbon atoms that may be contained in the aliphatic group of R ³ include a nitrogen atom, an oxygen atom, and / or a sulfur atom. When the aliphatic group of R ³ contains a sulfur atom, the sulfur atom may be contained in the aliphatic as a thiol group, a thioether group, and / or a disulfide group.

Among these, R ¹ is a hydrogen atom or an optionally substituted alkyl group having 1 to 5 carbon atoms from the viewpoints of curability at the time of forming the binder resin, heat resistance of the quantum dots, and improvement in heat and humidity resistance. , R ² is an optionally substituted alkylene group having 1 to 5 carbon atoms, R ³ is an aliphatic group having 1 to 10 carbon atoms, m is 1 to 10, and n is 1 to 1 A secondary thiol compound of 15 is preferred. One methylene group or two or more methylene groups not adjacent to each other in the alkylene group represented by R ² may be substituted with the same group as described above.

  Specific examples of primary thiol compounds include hexanedithiol, decanedithiol, ethylene glycol bisthioglycolate, 1,4-butanediol bisthioglycolate, trimethylolpropane tristhioglycolate, pentaerythritol tetrakisthioglycolate, ethylene Glycol bis (3-mercaptopropionate), 1,2-propylene glycol bis (3-mercaptopropionate), 1,3-propylene glycol bis (3-mercaptopropionate), 1,4-butanediol bis (3-mercaptopropionate), glycerin tris (3-mercaptopropionate), trimethylolpropane tris (3-mercaptopropionate), trimethylolethane tris (3-mercaptopropionate) ), Pentaerythritol tetrakis (3-mercaptopropionate), dipentaerythritol hexakis (3-mercaptopropionate) and the like.

  Specific examples of the secondary thiol compound include 1,4-bis (3-mercaptobutyryloxy) butane, 1,3,5-tris (3-mercaptobutyloxyethyl) -1,3,5-triazine-2 , 4, 6 (1H, 3H, 5H) -trione, pentaerythritol tetrakis (3-mercaptobutyrate), trimethylolpropane tris (3-mercaptobutyrate), trimethylolethane tris (3-mercaptobutyrate), etc. Can be mentioned. Specific examples of the tertiary thiol compound include tert-butyl mercaptan.

  Whether or not the thiol compound is contained in the light wavelength conversion composition can be confirmed by the same method as that for the compound having the heterocyclic group.

  The content of the thiol compound in the light wavelength conversion composition is preferably 5% by mass or more and 80% by mass or less. When the content of the thiol compound is 5% by mass or more, deterioration of the quantum dots can be further suppressed during a heat resistance test or a moist heat resistance test, and when the content of the thiol compound is 80% by mass or less, the light wavelength The conversion composition can be sufficiently cured. The content of the thiol compound can be determined by the same method as the content of the compound having a heterocyclic group. The lower limit of the content of the thiol compound in the light wavelength conversion composition is more preferably 20% by mass or more, and the upper limit is more preferably 60% by mass or less.

<< Curing agent >>
The curing agent is used for curing the light wavelength conversion composition by reacting with the compound having the heterocyclic group, or for the purpose of promoting the curing reaction. The “curing agent” in the present specification is a concept including not only a curing agent but also a curing accelerator. In this embodiment, since the thiol compound functions as a curing agent, it is not necessary to add a curing agent separately. Although it does not specifically limit as a hardening | curing agent, For example, it selects from the group which consists of an amine hardening | curing agent, a phenol hardening agent, an acid anhydride hardening | curing agent, an imidazole hardening agent, an organic phosphine hardening agent, and a cationic polymerization initiator. And one or more curing agents. Among these, amine-based curing agents are preferable because curing can proceed at a low reaction temperature.

  The content of the curing agent in the light wavelength conversion composition is preferably 0.1% by mass or more and 80% by mass or less. When the content of the curing agent is less than 0.1% by mass, the light wavelength conversion composition is difficult to cure, and when the content of the curing agent exceeds 80% by mass, the unreacted curing agent adversely affects the reliability. May cause effects. The lower limit of the content of the curing agent in the light wavelength conversion composition is more preferably 1% by mass or more, and the upper limit is more preferably 60% by mass or less.

<Amine-based curing agent>
Examples of the amine curing agent include aliphatic primary amines, secondary amines, tertiary amines, aromatic primary amines, secondary amines, tertiary amines, cyclic amines, guanidines, urea derivatives, and the like. Specifically, triethylenetetramine, diaminodiphenylmethane, diaminodiphenyl ether, metaxylenediamine, dicyandiamide, 1,8-diazabicyclo (5,4,0) -7-undecene, 1,5-diazabicyclo (4,3,0) Examples include trialkylamines such as -5-nonene, dimethylurea, guanylurea, triethylamine, and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris (dimethylaminomethyl) phenol, and the like.

<Phenolic curing agent>
Examples of the phenolic curing agent include bifunctional phenols such as hydroquinone, resorcinol, catechol, bisphenol A, tetrabromobisphenol A, bisphenol F, bisphenol AF, bisphenol AD, biphenol, dihydroxynaphthalene, binaphthol, fluorene type bisphenol; Resin, cresol novolak resin, triazine ring-containing phenol novolak resin, triazine ring-containing cresol novolak resin, bisphenol A novolak resin, tetrabromobisphenol A novolak resin, bisphenol AF novolak resin, bisphenol AD novolak resin, biphenol novolak resin, fluorene type bisphenol novolak Resin, dicyclopentadiene-pheno - novolac resins, dicyclopentadiene novolak resins such as cresol novolak resins; phenolic resole resins and resol resins such as cresol resole resin.

<Acid anhydride curing agent>
Examples of the acid anhydride curing agent include phthalic anhydride, hexahydrophthalic anhydride, trimellitic anhydride, and a condensation product of maleic anhydride and an unsaturated compound.

<Imidazole-based curing agent>
Examples of the imidazole curing agent include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 2-heptadecylimidazole, and 2-undecylimidazole.

<Organic phosphine curing agent>
Examples of organic phosphine curing agents include triphenylphosphine, tributylphosphine, tris (p-methylphenyl) phosphine, tris (p-methoxyphenyl) phosphine, tris (p-ethoxyphenyl) phosphine, triphenylphosphine / triphenylborate, Tetraphenylphosphine, tetraphenylborate and the like can be mentioned.

<Cationic polymerization initiator>
The cationic polymerization initiator is a compound that generates an acid by ionizing radiation or heat. The cationic polymerization initiator is not particularly limited, but has an acid-generating moiety, stable performance, high solubility in the compound having the heterocyclic group, and high storage stability of the light wavelength conversion composition. In view of the above, one or more compounds selected from the group consisting of sulfonium salts, iodonium salts, and diazonium salts are preferred. Examples of the ionizing radiation in this specification include visible light, ultraviolet rays, X-rays, electron beams, α rays, β rays, and γ rays.

(Sulfonium salt)
The sulfonium salt is not particularly limited, and examples thereof include benzylmethyl p-methoxycarbonyloxyphenylsulfonium hexafluoroantimonate, 2-methylbenzylmethyl p-hydroxyphenylsulfonium hexafluoroantimonate, and triarylsulfonium hexafluorophosphate. , Triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate, diphenyl-4- (phenylthio) phenylsulfonium hexa Fluoroantimonate, 4,4'-bis [diphenylsulfonio] diph Nylsulfide bishexafluorophosphate, 4,4′-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenylsulfide bishexafluoroantimonate, 4,4′-bis [di (β-hydroxyethoxy) phenylsulfonio ] Diphenyl sulfide bishexafluorophosphate, 7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone hexafluoroantimonate, 7- [Di (p-toluyl) sulfonio] -2-isopropylthioxanthone tetrakis (pentafluorophenyl) ) Borate, 4-phenylcarbonyl-4′-diphenylsulfonio-diphenylsulfide hexafluorophosphate, 4- (p-tert-butylphenylcarbonyl) -4′-diphenylsulfonio-diph Nils sulfide hexafluoroantimonate, 4- (p-tert- butylphenyl carbonyl) -4'-di (p- toluyl) sulfonio - diphenylsulfide tetrakis (pentafluorophenyl) like triarylsulfonium salts of borate, and the like.

(Iodonium salt)
The iodonium salt is not particularly limited, but diphenyliodonium tetrakis (pentafluorophenyl) borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, di (4-t-butylphenyl) iodonium hexafluorophosphate, di (4 -T-butylphenyl) iodonium hexafluoroantimonate, tricumyl iodonium tetrakis (pentafluorophenyl) borate, iodonium (4-methylphenyl) [4- (2-methylpropyl) phenyl] -hexafluorophosphate, di ( Diaryls such as 4-nonylphenyl) iodonium hexafluorophosphate, di (4-alkylphenyl) iodonium hexafluorophosphate An iodonium salt is mentioned.

(Diazonium salt)
The diazonium salt is not particularly limited, and examples thereof include benzenediazonium hexafluoroantimonate and benzenediazonium hexafluorophosphate.

  Among these, benzylmethyl p-methoxycarbonyloxyphenylsulfonium hexanium is used as a cationic polymerization initiator from the viewpoint that acid is rapidly generated by irradiation with ionizing radiation and compatibility with the compound having the heterocyclic group is good. Fluoroantimonate, 2-methylbenzylmethyl p-hydroxyphenylsulfonium hexafluoroantimonate, and triarylsulfonium hexafluorophosphate are preferred.

  Commercially available cationic polymerization initiators include, for example, Adeka optomer SP-100, 150, 152, 170, 172 (manufactured by ADEKA), photoinitiator 2074 (manufactured by Rhodia), Kayrad PCI-220, 620 (Japan) Kagaku), Irgacure 250 (BASF Japan), CPI-100P, 101A, 200K, 210S (Sun Apro), WPI-113, 116 (Wako Pure Chemical Industries), BBI-102, BBI-103, Examples thereof include TPS-102, TPS-103, DTS-102, DTS-103 (manufactured by Midori Chemical Co., Ltd.).

<< light scattering particles >>
The light-scattering particles are particles having an action of changing the traveling direction of light by scattering light that has entered a light wavelength conversion layer or a light wavelength conversion unit described later.

  The average particle size of the light-scattering particles is preferably 20 times or more and 2000 times or less, more preferably 50 times or more and 1000 times or less than the average particle size of the quantum dots. If the average particle size of the light scattering particles is less than 20 times the average particle size of the quantum dots, sufficient light scattering performance may not be obtained in the light wavelength conversion layer or the light wavelength conversion unit. When the average particle size of the particles exceeds 2000 times the average particle size of the quantum dots, the number of light scattering particles is reduced even if the addition amount is the same, so that the number of scattering points is reduced and a sufficient light scattering effect is obtained. There is a risk of not being able to. In addition, the average particle diameter of light-scattering particle | grains can be measured by the method similar to the average particle diameter of the quantum dot mentioned above.

  Further, the average particle diameter of the light scattering particles is preferably 1/300 or more and 1/20 or less, more preferably 1/200 or more and 1/30 or less, of the average film thickness of the light wavelength conversion layer described later. preferable. If the average particle diameter of the light scattering particles is less than 1/300 of the average film thickness of the light wavelength conversion layer, sufficient light scattering performance may not be obtained in the light wavelength conversion layer. If the particle diameter exceeds 1/20 of the average film thickness of the light wavelength conversion layer, the ratio of light scattering particles to the light wavelength conversion member decreases even if the addition amount is the same. Light scattering effect cannot be obtained.

  Specifically, the average particle diameter of the light-scattering particles is, for example, preferably from 0.1 μm to 10 μm, and more preferably from 0.3 μm to 5 μm. If the average particle diameter of the light scattering particles is less than 0.1 μm, the light wavelength conversion efficiency of the light wavelength conversion sheet may be insufficient. In order to obtain sufficient light scattering properties, It is necessary to increase the amount of addition. On the other hand, if the average particle diameter of the light-scattering particles exceeds 10 μm, the number of light-scattering particles is reduced even if the addition amount (% by mass) is the same, so that the number of scattering points is reduced and a sufficient light-scattering effect is obtained. I can't get it.

  The shape of the light-scattering particles is not particularly limited. For example, the shape is spherical (true sphere, approximately true sphere, elliptical sphere, etc.), polyhedral, rod (column, prism, etc.), flat plate, flake, irregular shape. Etc. In addition, when the shape of the light scattering particles is not spherical, the particle diameter of the light scattering particles can be a true spherical value having the same volume.

  The light scattering particles are preferably surface-treated with a silane coupling agent from the viewpoint of firmly fixing the light scattering particles in the binder resin. By surface-treating with a silane coupling agent, it can be chemically bonded to a binder resin described later.

  The silane coupling agent is a group consisting of a vinyl group, an epoxy group, a styryl group, a methacryl group, an acrylic group, an amino group, a ureido group, a thiol group, a sulfide group and an isocyanate group, depending on the type of polymerizable compound used. Those having one or more reactive functional groups selected from can be used. When a compound having a (meth) acryloyl group is used as the polymerizable compound, the coupling agent is at least one kind of reactivity selected from the group consisting of a thiol group, a (meth) acryloyl group, a vinyl group, and a styryl group. It preferably has a functional group. When a compound having at least one group selected from the group consisting of an epoxy group, an isocyanate group, and a hydroxyl group is used as the polymerizable compound, the silane coupling agent is an epoxy group, an isocyanate group, a thiol group, and an amino group. It preferably has at least one reactive functional group selected from the group consisting of groups.

  The light-scattering particles may be organic particles such as acrylic resin particles, styrene resin particles, melamine resin particles, and urethane resin particles, but the luminance change rate before and after the heat resistance test can be reduced, and light Inorganic particles are preferable because incident light on the wavelength conversion sheet can be suitably scattered, and light wavelength conversion efficiency for the incident light can be suitably improved.

Inorganic particles include aluminum-containing compounds such as Al ₂ O ₃ , zirconium-containing compounds such as ZrO ₂ , tin-containing compounds such as antimony-doped tin oxide (ATO) and indium tin oxide (ITO), and magnesium-containing materials such as MgO and MgF _2. At least one compound selected from the group consisting of compounds, titanium-containing compounds such as TiO ₂ and BaTiO ₃ , antimony-containing compounds such as Sb ₂ O ₅ , silicon-containing compounds such as SiO ₂ , and zinc-containing compounds such as ZnO Particles. Since these inorganic particles can increase the difference in refractive index with the binder resin, they are also preferable from the viewpoint of obtaining a large Mie scattering intensity. Since the light wavelength conversion efficiency with respect to the incident light by the light wavelength conversion sheet 10 can be improved more suitably, the light scattering particles may be made of two or more kinds of materials.

  The content of the light-scattering particles with respect to the total solid mass of the light wavelength conversion composition is preferably 1% by mass or more and 50% by mass or less, and more preferably 3% by mass or more and 30% by mass or less. If the content of the light scattering particles is less than 1% by mass, the light scattering effect may not be sufficiently obtained, and if the content of the light scattering particles exceeds 50% by mass, Mie scattering occurs. Since it becomes difficult, the light scattering effect may not be sufficiently obtained, and the processability may be deteriorated because there are too many light scattering particles.

<<< Light wavelength conversion particle >>>
The light wavelength conversion particle 1 shown in FIG. 1 is a particle that converts the wavelength of incident light into another wavelength. The light wavelength conversion particle 1 includes quantum dot-containing resin particles 2. The quantum dot-containing resin particle 2 includes a light-transmitting binder resin 3 and one or more quantum dots 4 included in the binder resin 3, and the quantum dot-containing resin particle 2 includes the light wavelength conversion described above. It is a cured product of the composition. The light wavelength conversion particle 1 may include one kind of quantum dot as the quantum dot 4, but as shown in FIG. 1, the first quantum dot 4A is different from the first quantum dot 4A. And a second quantum dot 4B having an emission band in a wavelength region. The light wavelength conversion particle 1 shown in FIG. 1 further includes a coat layer 5 that covers the surface of the quantum dot-containing resin particle 2.

  In the light wavelength conversion particles 1, the content of the sulfur element in the light wavelength conversion particles 1 measured by fluorescent X-ray analysis (XRF) is preferably 0.5% by mass or more. When the sulfur element content is 0.5 mass% or more, the deterioration of the quantum dots can be further suppressed. The content of elemental sulfur can be measured by using a fluorescent X-ray analyzer (product name “EDX-800HS”, manufactured by Shimadzu Corporation). The lower limit of the content of sulfur element in the light wavelength conversion particles 1 measured by X-ray fluorescence analysis (XRF) is more preferably 1% by mass or more, and the upper limit of the content of sulfur element is 20% by mass or less. More preferably, it is more preferably 10% by mass or less. If the content of elemental sulfur exceeds 20% by mass, sufficient curing may not be performed during the formation of the light wavelength conversion particles.

  The average particle diameter of the light wavelength conversion particles 1 is preferably not less than twice the average particle diameter of the quantum dots 4 and not more than 50 μm. Since the distance from the quantum dot 4 to the surface of the light wavelength conversion particle 1 can be sufficiently secured when the average particle diameter of the light wavelength conversion particle 1 is twice or more than the average particle diameter of the quantum dot 4, The deterioration of the quantum dots 4 from oxygen can be further suppressed. In addition, when the average particle diameter of the light wavelength conversion particles 1 is 50 μm or less, the dispersibility is good, and the light wavelength conversion member is less likely to be a defect when processed. The average particle diameter of the light wavelength conversion particles 1 is obtained by measuring the particle diameters of 20 light wavelength conversion particles in the observation of the light wavelength conversion particles with a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM), and averaging the average particle diameter. It shall be obtained by calculating the value. The lower limit of the average particle diameter of the light wavelength conversion particles 1 is more preferably 10 nm or more, further preferably 20 nm or more, from the viewpoint of further suppressing the deterioration of the quantum dots, and the average of the light wavelength conversion particles 1 The upper limit of the particle diameter is more preferably 30 μm or less, and further preferably 10 μm or less.

  The shape of the light wavelength conversion particle 1 is not particularly limited. For example, it is spherical (true sphere, approximately true sphere, elliptical sphere, etc.), polyhedral, rod (column, prism, etc.), flat, flake, indefinite. Examples include shape. In addition, when the shape of the light wavelength conversion particle 1 is not spherical, the particle diameter of the light wavelength conversion particle 1 can be a true spherical value having the same volume.

  The light wavelength conversion particle 1 preferably contains one or more quantum dots 4 per particle. If the number of quantum dots contained in one light wavelength conversion particle is less than one, the brightness may be lowered. The number of quantum dots contained in one light wavelength conversion particle is a magnification of 100,000 to 500,000 times in a cross section of 20 light wavelength conversion particles randomly using a transmission electron microscope or a scanning transmission electron microscope. The number of quantum dots contained in one light wavelength conversion particle is calculated from the obtained cross-sectional image, and the average value of the calculated number of quantum dots is calculated.

  The light wavelength conversion particle 1 includes two or more quantum dots 4 per one, and the average distance between the quantum dots 4 in the quantum dots 4 included in one light wavelength conversion particle 1 is 1 nm or more. It is preferable. If the average distance between the quantum dots is less than 1 nm, the light emission efficiency may decrease due to concentration quenching that causes quenching due to energy transfer between the quantum dots. The average distance between the quantum dots was obtained by photographing a cross section of 20 light wavelength conversion particles randomly at a magnification of 100,000 to 500,000 times using a transmission electron microscope or a scanning transmission electron microscope. The distance between the quantum dots is calculated from the above image, and the average value of the calculated distance between the quantum dots is calculated. The upper limit of the average distance between the quantum dots 4 in the quantum dots 4 is more preferably 100 nm or less.

<< Quantum dot-containing resin particles >>
As described above, the quantum dot-containing resin particles 2 are a cured product of the light wavelength conversion composition. Therefore, the binder resin 3 of the quantum dot-containing resin particle 2 is a resin made of a reaction product of the compound having the heterocyclic group and the thiol compound, and the quantum dot 4 of the quantum dot-containing resin particle 2 is light. It is the quantum dot demonstrated in the column of the wavelength conversion composition. In the present specification, the reaction product of the compound having the heterocyclic group and the thiol compound contains components other than the component derived from the compound having the heterocyclic group and the component derived from the thiol compound. May be.

  Since the binder resin 3 is a resin composed of a reaction product of the compound having the heterocyclic group and the thiol compound, the binder resin 3 contains a sulfur element, but the surface of the quantum dot shell is made of a sulfur compound or the like. Therefore, even when sulfur element is detected from the light wavelength conversion particles, the detected sulfur element is not necessarily the sulfur element contained in the binder resin. For this reason, it is confirmed as follows whether binder resin contains a sulfur element. First, since the ligand of the quantum dot is bonded to the surface of the shell and the size of the ligand coordination site is usually within about 1 nm, it does not exist at a position 3 nm or more away from the surface of the shell. Therefore, sulfur element is detected by X-ray photoelectron spectroscopy (XPS) or energy dispersive X-ray analysis (EDS) at any position inside or inside the binder resin that is 3 nm or more away from the surface of the quantum dot shell. In this case, it can be determined that the binder resin contains sulfur element.

<< Coat layer >>
The coat layer 5 covers the surface of the quantum dot-containing resin particles 2. The function of the coat layer 5 is not particularly limited. For example, the coat layer 5 has a function of maintaining the shape of the quantum dot-containing resin particles 2, a function of preventing elution of components in the quantum dot-containing resin particles to the outside of the particles, Anti-penetration function of components in dispersion liquid and composition, barrier function for oxygen and water vapor, anti-reflection function of excitation light incident on quantum dot-containing resin particles, and quantum when used as dispersion liquid or composition It has at least one of the functions of imparting dispersibility to dot-containing resin particles.

  The film thickness of the coat layer 5 depends on the function exhibited by the coat layer 5, but is preferably 10 nm or more and 5000 nm or less from the viewpoint of ease of production and appropriate resin particle size. More preferably, it is 1000 nm or less. In particular, when the coat layer 5 exhibits a barrier property-imparting function, the thickness of the coat layer 5 is preferably 50 nm or more and 1000 nm or less from the viewpoint of preventing cracks and the like of the coat layer while maintaining the barrier property. preferable. Further, the coating layer 5 exhibits an antireflection function, and the refractive index of the binder resin of the light wavelength conversion layer, which will be described later, <the coating layer <the binder resin of the quantum dot-containing resin particles or the binder resin of the light wavelength conversion layer> coating When satisfying the relationship of the binder resin of the layer> quantum dot-containing resin particles, the coating layer 5 from the viewpoint of suppressing reflection on the surface of the light wavelength conversion particles 1 and efficiently incorporating the excitation light into the quantum dot-containing resin particles 2. More preferably, the film thickness is 50 nm or more and 300 nm or less. The film thickness of the coating layer 5 is obtained by photographing a cross section of the light wavelength conversion particle 1 using a scanning electron microscope (SEM), measuring the film thickness of the light wavelength conversion particle 1 in 20 positions in the image of the cross section, It is set as the average value of the film thickness of 20 places.

  Although depending on the function of the coating layer 5, when the coating layer 5 has the function of maintaining the shape of the quantum dot-containing resin particles, the coating layer 5 is formed using, for example, a coating layer composition containing a polymerizable compound. Is possible.

<Polymerizable compound>
The polymerizable compound (curable compound) contained in the coating layer composition is a polymerizable compound, for example, an ionizing radiation polymerizable compound (ionizing radiation curable compound) or a thermopolymerizable compound (thermosetting compound). Is mentioned.

(Ionizing radiation polymerizable compound)
The ionizing radiation polymerizable compound has at least one ionizing radiation polymerizable functional group in the molecule. Examples of the ionizing radiation polymerizable functional group include ethylenically unsaturated groups such as a (meth) acryloyl group, a vinyl group, and an allyl group. The “(meth) acryloyl group” means to include both “acryloyl group” and “methacryloyl group”.

  Examples of the ionizing radiation polymerizable compound include an ionizing radiation polymerizable monomer, an ionizing radiation polymerizable oligomer, and an ionizing radiation polymerizable prepolymer, and these can be appropriately adjusted and used. As the ionizing radiation polymerizable compound, a combination of an ionizing radiation polymerizable monomer and an ionizing radiation polymerizable oligomer or an ionizing radiation polymerizable prepolymer is preferable.

  Examples of the ionizing radiation polymerizable monomer include monomers containing a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and ethylene glycol di (meth) acrylate. , Diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tetramethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylol ethanetri (meth) ) Acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaeryth Ritorutetora (meth) acrylate, dipentaerythritol hexa (meth) acrylate, glycerol (meth) (meth) acrylic acid esters such as acrylate.

  As the ionizing radiation polymerizable oligomer, a polyfunctional oligomer having two or more functional groups is preferable, and a polyfunctional oligomer having three (trifunctional) or more ionizing radiation polymerizable functional groups is more preferable. Examples of the polyfunctional oligomer include polyester (meth) acrylate, urethane (meth) acrylate, polyester-urethane (meth) acrylate, polyether (meth) acrylate, polyol (meth) acrylate, melamine (meth) acrylate, and isocyanurate. (Meth) acrylate, epoxy (meth) acrylate, etc. are mentioned.

  The ionizing radiation polymerizable prepolymer has a weight average molecular weight exceeding 10,000, and the weight average molecular weight is preferably 10,000 or more and 80,000 or less, and more preferably 10,000 or more and 40,000 or less. When the weight average molecular weight exceeds 80,000, the viscosity is high, so that the coating suitability is lowered, and the appearance of the obtained light wavelength conversion member may be deteriorated. For this reason, when the ionizing radiation polymerizable prepolymer having a weight average molecular weight exceeding 80,000 is used, it is preferable to mix and use the polymerizable monomer and the polymerizable oligomer. Examples of the polyfunctional polymerizable prepolymer include urethane (meth) acrylate, isocyanurate (meth) acrylate, polyester-urethane (meth) acrylate, and epoxy (meth) acrylate.

(Thermopolymerizable compound)
The thermopolymerizable compound has at least one thermopolymerizable functional group in the molecule. Examples of the thermally polymerizable functional group include heterocyclic groups containing the above oxygen atoms, silanol groups, and alkoxysilyl groups. Examples of the thermopolymerizable compound include the same compounds as the compound having the heterocyclic group described above, and thus the description thereof is omitted here.

<<< Method for Producing Light Wavelength Conversion Particles >>>
The light wavelength conversion particles 1 can be produced, for example, by the following method. First, ionizing radiation or heat is applied to the light wavelength conversion composition and cured to obtain a cured product of the light wavelength conversion composition. And this hardened | cured material is grind | pulverized, for example with a bead mill. Thereby, the light wavelength conversion particle 1 can be obtained.

  Moreover, the light wavelength conversion particle | grains 1 can also be produced also with the following method. First, the light wavelength conversion composition is dispersed in a granular form in a poor solvent such as water. Then, in a state where the light wavelength conversion composition is dispersed in the form of particles, the polymerizable compound in the light wavelength conversion composition is polymerized by, for example, suspension polymerization or emulsion polymerization to obtain light wavelength conversion particles 1. “Poor solvent” means a solvent in which the light wavelength conversion composition is hardly dissolved, and examples thereof include polar solvents such as water. The light wavelength conversion composition preferably contains a polymerization initiator.

<<< Light wavelength conversion particle dispersion >>>
The light wavelength conversion particle dispersion liquid includes a dispersion medium and the light wavelength conversion particles 1 dispersed in the dispersion medium. Examples of the dispersion medium include, but are not limited to, water; alcohols such as methanol, ethanol, propanol, and isopropyl alcohol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; toluene, cyclohexane, and the like. Among these, ethanol and toluene are preferable from the viewpoint of improving the dispersibility of the quantum dots.

  The content of the light wavelength conversion particles 1 in the light wavelength conversion particle dispersion is preferably 1% by mass or more and 50% by mass or less, and more preferably 5% by mass or more and 30% by mass or less. If the content of the light wavelength conversion particles is less than 1% by mass, a sufficient wavelength conversion function may not be obtained. If the content of the light wavelength conversion particles 1 exceeds 50% by mass, precipitation occurs. This may result in insufficient dispersibility in the dispersion.

<<< Light wavelength conversion particle-containing composition >>>
The composition containing light wavelength conversion particles includes the light wavelength conversion particles 1 and a polymerizable compound that becomes a binder resin 16 to be described later after curing. The light wavelength conversion particle-containing composition may further contain a polymerization initiator in addition to the light wavelength conversion particle 1 and the polymerizable compound. The light wavelength conversion particle-containing composition preferably further contains light scattering particles, and may contain an additive or a solvent.

<< polymerizable compound >>
As the polymerizable compound of the composition containing the light wavelength conversion particles, the same compound as the polymerizable compound described in the column of the coat layer can be used, and the description thereof is omitted here. In addition, when forming the light source mentioned later using a light wavelength conversion particle containing composition, the polymerizable compound in a light wavelength conversion particle containing composition is an epoxy compound from a viewpoint of sealing the light-emitting body in a light source. And a polysiloxane compound having a silanol group and / or an alkoxysilyl group. Moreover, when forming the color filter mentioned later using a light wavelength conversion particle containing composition, the polymeric compound in a light wavelength conversion particle containing composition is alkali-soluble from a viewpoint of patterning each light wavelength conversion layer. A resin is preferred. The alkali-soluble resin has an acidic group such as a polymerizable functional group and a carboxyl group, and the alkali-soluble resin is appropriately selected and used as long as it is soluble in an alkali developer used for patterning. Can do.

<< Polymerization initiator >>
The polymerization initiator is a component that is decomposed by light or heat to generate radicals or ionic species to initiate or advance polymerization (crosslinking) of the polymerizable compound. Examples of the polymerization initiator include a photopolymerization initiator (for example, a photo radical polymerization initiator, a photo cation polymerization initiator, a photo anion polymerization initiator), a thermal polymerization initiator (for example, a thermal radical polymerization initiator, a thermal cation polymerization initiator). , Thermal anionic polymerization initiator), or a mixture thereof.

  Examples of the photo radical polymerization initiator include benzophenone compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin ether compounds, thioxanthones, and the like.

  Examples of commercially available photo radical polymerization initiators include IRGACURE 184, IRGACURE 369, IRGACURE 379, IRGACURE 651, IRGACURE 819, IRGACURE 907, IRGACURE 2959, IRGACURE OXE01, and Lucillin TPO (all manufactured by BASF Japan 9) ADEKA), SPEEDCURE EMK (Nihon Sebel Hegner), benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether (all manufactured by Tokyo Chemical Industry Co., Ltd.) and the like.

  Examples of the thermal radical polymerization initiator include peroxides and azo compounds. Among these, a polymer azo initiator composed of a polymer azo compound is preferable. Examples of the polymer azo initiator include those having a structure in which a plurality of units such as polyalkylene oxide and polydimethylsiloxane are bonded via an azo group.

  Examples of the polymer azo initiator having a structure in which a plurality of units such as polyalkylene oxide are bonded via the azo group include, for example, a polycondensate of 4,4′-azobis (4-cyanopentanoic acid) and polyalkylene glycol. And polycondensate of 4,4′-azobis (4-cyanopentanoic acid) and polydimethylsiloxane having a terminal amino group.

  Examples of the peroxide include ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, peroxy ester, diacyl peroxide, and peroxydicarbonate.

  Examples of commercially available thermal radical polymerization initiators include perbutyl O, perhexyl O, perbutyl PV (all manufactured by NOF Corporation), V-30, V-501, V-601, and VPE-0201. , VPE-0401, VPE-0601 (both manufactured by Wako Pure Chemical Industries, Ltd.) and the like.

  As the photocationic polymerization initiator and the thermal cationic polymerization initiator, those similar to the cationic polymerization initiator described in the column of the curing agent can be used, and thus the description thereof is omitted here.

  The content of the polymerization initiator in the light wavelength conversion particle-containing composition is preferably 0.3 parts by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the polymerizable compound. When the content of the polymerization initiator is less than 0.3 parts by mass, the polymerizable compound is hardly cured, and when it exceeds 5.0 parts by mass, the light wavelength conversion sheet may be yellowed. .

<< light scattering particles >>
Since the light-scattering particles of the composition containing light wavelength conversion particles are the same as the light-scattering particles described in the column of the light wavelength conversion composition, description thereof will be omitted here.

<< Additives >>
Although it does not specifically limit as an additive, The compound which suppresses the oxidation and deterioration of a quantum dot is preferable. Examples of the compound that suppresses oxidation and deterioration of the quantum dots include phenol compounds, amine compounds, sulfur compounds, carboxy group-containing compounds, hydrazine compounds, amide compounds, hindered amine compounds, and the like. The additive may have a polymerizable functional group such as an ionizing radiation polymerizable functional group or a heat polymerizable functional group.

<< Solvent >>
Examples of the solvent include, but are not limited to, alcohols such as methanol, ethanol, propanol, and isopropyl alcohol; ketones such as methyl ethyl ketone and methyl isobutyl ketone, toluene, and cyclohexane.

<<< Light wavelength conversion member >>>
A light wavelength conversion member contains the hardened | cured material of the said light wavelength conversion particle | grains or the said light wavelength conversion composition. The shape and structure of the light wavelength conversion member can be appropriately changed depending on the location where the light wavelength conversion member is incorporated. For example, the light wavelength conversion member may be a light wavelength conversion sheet as described below, a light source described later, or a light wavelength conversion layer installed near the light source. The light wavelength conversion member may be a color filter.

<<< Light wavelength conversion sheet >>>
The light wavelength conversion sheet 10 shown in FIG. 2 is one form of a light wavelength conversion member, converts the wavelength of some of the incident light to other wavelengths, and another part of the incident light and It is a sheet that emits light whose wavelength has been converted. The light wavelength conversion sheet 10 shown in FIG. 2 includes a light wavelength conversion layer 11, light transmissive substrates 12 and 13 provided on both surfaces of the light wavelength conversion layer 11, and light in the light transmissive substrates 12 and 13. Light diffusion layers 14 and 15 are provided on the side opposite to the surface on the wavelength conversion layer 11 side.

  In the light wavelength conversion sheet 10, the surfaces of the light diffusion layers 14 and 15 constitute the surfaces 10 </ b> A and 10 </ b> B of the light wavelength conversion sheet 10. The light wavelength conversion sheet 10 includes the light transmissive substrates 12 and 13 but does not include the barrier layer, and thus does not include the barrier film including the light transmissive substrate and the barrier layer. The light wavelength conversion sheet 10 has a structure of a light diffusion layer 14 / light transmissive substrate 12 / light wavelength conversion layer 11 / light transmissive substrate 13 / light diffusion layer 15; If it has, the structure of a light wavelength conversion sheet will not be specifically limited.

  In the light wavelength conversion sheet 10, as shown in FIG. 3, when light is incident from the surface 10 </ b> A of the light wavelength conversion sheet 10, the light L <b> 1 incident on the quantum dots 4 in the light wavelength conversion layer 11 is It is converted into light L2 having a wavelength different from that of the light L1, and is emitted from the surface 10B. On the other hand, even when light is incident from the surface 10A, the light L1 passing between the quantum dots 4 in the light wavelength conversion layer 11 is emitted from the surface 10B without being wavelength-converted.

In the light wavelength conversion sheet 10, excellent heat resistance and moist heat resistance are obtained by the binder resin 3 of the light wavelength conversion layer 11. Therefore, the water vapor transmission rate (WVTR: Water) at 40 ° C. and 90% relative humidity is obtained in the entire sheet. The Vapor Transmission Rate may be 0.1 g / (m ² · 24 h) or more. The water vapor transmission rate is a numerical value obtained by a method based on JIS K7129: 2008. The water vapor transmission rate can be measured using a water vapor transmission rate measuring device (product name “PERMATRAN-W3 / 31”, manufactured by MOCON). Since the conventional light wavelength conversion sheet is formed with a barrier film, the light wavelength conversion sheet 10 has a higher water vapor transmission rate than the conventional light wavelength conversion sheet, that is, the light wavelength conversion sheet 10 is Moisture permeates more easily than conventional light wavelength conversion sheets. As will be described later, when the light wavelength conversion sheet includes an optical member in addition to the light wavelength conversion layer, the water vapor transmission rate is the water vapor transmission rate of the entire light wavelength conversion sheet including the optical member.

In the light wavelength conversion sheet 10, excellent heat resistance and heat-and-moisture resistance are obtained by the binder resin 3 of the light wavelength conversion layer 11, and therefore the oxygen transmission rate (OTR: Oxygen at 23 ° C. and 90% relative humidity) of the entire sheet. Transmission Rate) may be 0.1 cm ³ / (m ² · 24 h · atm) or more. The light wavelength conversion sheet 10 may satisfy the water vapor transmission rate and the oxygen transmission rate at the same time. The oxygen permeability is a numerical value obtained by a method based on JIS K7126: 2006. The oxygen permeability can be measured using an oxygen gas permeability measuring device (product name “OX-TRAN 2/21”, manufactured by MOCON). Since the conventional light wavelength conversion sheet is formed with a barrier film, the light wavelength conversion sheet 10 has a higher oxygen transmittance than the conventional light wavelength conversion sheet, that is, the light wavelength conversion sheet 10 is Compared with the conventional light wavelength conversion sheet, not only moisture but also oxygen is easily transmitted. Similarly to the above, when the light wavelength conversion sheet includes an optical member in addition to the light wavelength conversion layer, the oxygen transmittance is the oxygen transmittance of the entire light wavelength conversion sheet including the optical member.

In the light wavelength conversion sheet 10, the water vapor transmission rate at 40 ° C. and a relative humidity of 90% may be 1 g / (m ² · 24 h) or more, and in the light wavelength conversion sheet 10 at 23 ° C. and a relative humidity of 90%. May have an oxygen permeability of 1 cm ³ / (m ² · 24 h · atm) or more.

  The internal haze value in the light wavelength conversion sheet 10 is preferably 50% or more. The internal haze is a haze value resulting from the inside of the light wavelength conversion sheet, and does not take into account the uneven shape of the surface of the light wavelength conversion sheet. When the internal haze value of the light wavelength conversion sheet 10 is 50% or more, light can be sufficiently diffused by the internal haze to excite the quantum dots a plurality of times, and the external haze value can be made smaller. Can do. The internal haze value in the light wavelength conversion sheet 10 is preferably 60% or more, and more preferably 80% or more.

  The external haze value in the light wavelength conversion sheet 10 is preferably 10% or less (including 0%), and more preferably 5% or less. The external haze value is attributed only to the uneven shape on the surface of the light wavelength conversion sheet. When the external haze value of the light wavelength conversion sheet 10 is 10% or less, retroreflection tends to occur in a retroreflective sheet such as a lens sheet.

In the light wavelength conversion sheet 10, the external haze value of the light wavelength conversion sheet 10 is preferably smaller than the internal haze value of the light wavelength conversion sheet 10. That is, the light wavelength conversion sheet 10 preferably satisfies the relationship of the following formula.
Internal haze value> External haze value

  The internal haze value and the external haze value can be determined using a haze meter (product name “HM-150”, manufactured by Murakami Color Research Laboratory). Specifically, first, the total haze value of the light wavelength conversion sheet is measured according to JIS K7136: 2000 using a haze meter. Thereafter, a triacetylcellulose base material (product name “Panaclean PD-S1”, manufactured by Panac Co., Ltd.) having a thickness of 25 μm is formed on both surfaces of the light wavelength conversion sheet via a transparent optical adhesive layer (product name “Panaclean PD-S1”, manufactured by Panac Corporation). TD60UL "(manufactured by FUJIFILM Corporation) is pasted. Thereby, the uneven shape on the surface of the light wavelength conversion sheet is crushed, and the surface of the light wavelength conversion sheet is flattened. And in this state, an internal haze value is calculated | required by measuring a haze value according to JISK7136: 2000 using a haze meter (product name "HM-150", Murakami Color Research Laboratory make). The external haze value is obtained by subtracting the internal haze from the total haze. The “external haze value” in the present specification means the external haze value of the entire light wavelength conversion sheet. That is, the external haze value in this specification means the sum of the external haze value on one surface of the light wavelength conversion sheet and the external haze value on the other surface of the light wavelength conversion sheet.

  The internal haze value and the external haze value are related. Specifically, when the internal haze value increases, the external haze tends to decrease even when the same surface irregularities are present. This is considered to be due to the following reason. JIS K7136: 2000 stipulates that the haze is the percentage of transmitted light that passes through the test piece and is 0.044 rad (2.5 °) or more away from the incident light due to forward scattering. Yes. That is, in the definition of haze, transmitted light deviated by 2.5 ° or more with respect to incident light is measured as haze, but is not measured as haze if transmitted light is less than 2.5 ° with respect to incident light. On the other hand, in the light wavelength conversion sheet having a large internal haze, the light is more scattered inside the sheet than in the light wavelength conversion sheet having a smaller internal haze. Transmitted light below 2.5 ° is reduced. For this reason, when the light wavelength conversion sheet having a large internal haze and the light wavelength conversion sheet having a small internal haze have the same surface irregularities, the light wavelength conversion sheet having a large internal haze has a higher internal haze than that. Compared with a small light wavelength conversion sheet, the influence of surface irregularities is reduced. Therefore, considering only the effect of surface irregularities present on the sheet surface, even if the light wavelength conversion sheet having a large internal haze and the light wavelength conversion sheet having a smaller internal haze have the same surface irregularities, The light wavelength conversion sheet having a large haze has not only the transmitted light of less than 2.5 ° with respect to the incident light emitted from the surface unevenness, but also the surface unevenness, compared to the light wavelength conversion sheet having a smaller internal haze. Also, the amount of transmitted light deviated by 2.5 ° or more with respect to the incident light emitted from the light source decreases. Therefore, it is considered that when the internal haze value increases, the external haze decreases even when the same surface irregularities are provided.

  In the light wavelength conversion sheet 10, in order to make the external haze value of the light wavelength conversion sheet 10 smaller than that of the light wavelength conversion sheet 10, for example, adding light scattering particles inside the light wavelength conversion sheet 10 can be mentioned. . When the light wavelength conversion sheet includes at least one of a barrier film and a light diffusion layer, the light scattering particles may be added to the barrier film in addition to the light wavelength conversion layer 11, and It may also be added in the diffusion layer. When the layer to which light scattering particles are added is the outermost layer, it may be accompanied by external haze. Therefore, the relationship between the internal haze and the external haze is satisfied by controlling the surface irregularities of the outermost layer. Can do.

  The ratio of the external haze value to the internal haze value in the light wavelength conversion sheet 10 (external haze value / internal haze value) is preferably 0 or more and 0.1 or less, and more preferably 0 or more and 0.05 or less. . If this ratio is within this range, the quantum dots can be excited a plurality of times by sufficiently diffusing light by the internal haze.

  The arithmetic average roughness (Ra) of the surfaces 10A and 10B of the light wavelength conversion sheet 10 is preferably 0.1 μm or more, and more preferably 0.5 μm or more. The reason why the Ra of the surfaces 10A and 10B of the light wavelength conversion sheet 10 is preferably 0.1 μm is as follows. The light wavelength conversion sheet is in contact with an optical plate or a lens sheet, which will be described later, in the backlight device. Since there is a possibility that a pattern called wet-out, which is wetted with water, may be formed at the interface between the optical wavelength conversion sheet and the lens sheet, the optical wavelength conversion sheet 10 and the optical plate or lens sheet In order to prevent sticking, Ra is more preferably 0.1 μm or more.

  The definition of “Ra” is based on JIS B0601: 1994. Ra can be measured using, for example, a surface roughness measuring instrument (product name “SE-3400”, manufactured by Kosaka Laboratory Ltd.).

  When a light source that emits blue light is used to irradiate a light wavelength conversion sheet 10 that includes both quantum dots that convert blue light into green light and quantum dots that convert blue light into red light, the transmitted light in the light wavelength conversion sheet The ratio of the peak value of green light intensity to the peak value of blue light intensity (peak value of green light intensity / peak value of blue light intensity) is 0.3 to 2.0 It is preferable that it is 0.5 or more and 1.5 or less.

  The ratio of the peak value of the light intensity of the red light to the peak value of the light intensity of the blue light in the transmitted light in the light wavelength conversion sheet 10 (the peak value of the light intensity of the red light / the peak value of the light intensity of the blue light) is 0.3 or more and 2.0 or less, and more preferably 0.5 or more and 1.5 or less.

  In this specification, “blue light” is light having a wavelength range of 380 nm or more and less than 480 nm, “green light” is light having a wavelength range of 480 nm or more and less than 590 nm, and “red light” is It is light having a wavelength range of 590 nm to 750 nm. The light intensity of each light can be measured using a spectral radiance meter (for example, product name “CS2000”, manufactured by Konica Minolta).

  The thickness of the light wavelength conversion sheet 10 is preferably 10 μm or more and 500 μm or less. If the average thickness of the light wavelength conversion sheet 10 is within this range, it is suitable for reducing the weight and thickness of the backlight device.

  The thickness of the light wavelength conversion sheet 10 is obtained by photographing a cross section of the light wavelength conversion sheet 10 using a scanning electron microscope (SEM), a transmission electron microscope (TEM), or a scanning transmission electron microscope (STEM). In this image, the thickness of the light wavelength conversion sheet 10 is measured at 20 locations, and the average value of the thicknesses at the 20 locations is measured. Among these, considering that the film thickness of the light wavelength conversion sheet 10 is on the order of μm, it is preferable to use SEM. In the case of SEM, the acceleration voltage is preferably 30 kV and the magnification is preferably 1000 to 7000 times. In the case of TEM or STEM, the acceleration voltage is preferably 30 kV and the magnification is preferably 50,000 to 300,000 times.

<< Light wavelength conversion layer >>
The light wavelength conversion layer 11 includes light wavelength conversion particles 1 and a binder resin 16 that is a cured product of a polymerizable compound. The light wavelength conversion layer 11 shown in FIG. 2 further includes light scattering particles 17. By including the light scattering particles 17, the light wavelength conversion efficiency and the internal haze can be increased. The light wavelength conversion particles 1 included in the light wavelength conversion layer 11 are the same as the light wavelength conversion particles 1 described in the column of the light wavelength conversion particles, and the light scattering particles included in the light wavelength conversion layer 11. 17 is the same as the light-scattering particles described in the column of the light wavelength conversion composition, and the description thereof is omitted here.

  In the light wavelength conversion layer 11, the content of sulfur element in the light wavelength conversion layer 11 measured by fluorescent X-ray analysis (XRF) is preferably 0.5% by mass or more. When the sulfur element content is 0.5 mass% or more, the deterioration of the quantum dots can be further suppressed. The content of elemental sulfur can be measured by using a fluorescent X-ray analyzer (product name “EDX-800HS”, manufactured by Shimadzu Corporation). The lower limit of the content of sulfur element in the light wavelength conversion layer 11 measured by fluorescent X-ray analysis (XRF) is more preferably 1% by mass or more, and the upper limit of the content of sulfur element is 20% by mass or less. It is more preferable that it is 10% by mass or less. When the content of elemental sulfur exceeds 20% by mass, there is a risk that sufficient curing will not be performed during the formation of the light wavelength conversion layer.

  The film thickness of the light wavelength conversion layer 11 is preferably 10 μm or more and 200 μm or less. If the average thickness of the light wavelength conversion layer 11 is within this range, it is suitable for reducing the weight and thickness of the backlight device. The film thickness of the light wavelength conversion layer 11 is obtained by photographing a cross section of the light wavelength conversion layer 11 using a scanning electron microscope (SEM), and measuring the film thickness of the light wavelength conversion layer 11 in 20 positions in the image of the cross section. , And the average value of the film thickness at the 20 locations. The upper limit of the average film thickness of the light wavelength conversion layer 11 is more preferably less than 170 μm.

<Binder resin>
As the binder resin 16, a cured product of a polymerizable compound can be used. As the polymerizable compound, since the same compound as the polymerizable compound described in the column of the light wavelength conversion particle-containing composition can be used, the description is omitted here.

  The absolute value of the refractive index difference between the light-scattering particles 17 and the binder resin 16 is preferably 0.05 or more, and more preferably 0.10 or more, from the viewpoint of obtaining sufficient light scattering. Note that either of the refractive index of the light scattering particles 17 and the refractive index of the binder resin 16 may be larger. Here, as a method for measuring the refractive index of the light-scattering particles before being included in the light wavelength conversion layer, for example, the Becke method, the minimum deflection angle method, the deflection angle analysis, the mode line method, the ellipsometry method, etc. can do. As a method for measuring the refractive index of the binder resin and light scattering particles in the light wavelength conversion layer, for example, the light scattering particles or the host matrix fragments are taken out from the cured light wavelength conversion layer in some form. The Becke method can be used on In addition, the refractive index difference between the binder resin and the light scattering particles is measured using a phase shift laser interference microscope (such as a phase shift laser interference microscope manufactured by FK Optical Laboratory or a two-beam interference microscope manufactured by Mizoji Optical Industry Co., Ltd.). can do.

<< light transmissive substrate >>
The thickness of the light-transmitting substrates 12 and 13 is not particularly limited, but is preferably 10 μm or more and 300 μm or less. If the thickness of the light-transmitting substrates 12 and 13 is less than 10 μm, there is a risk of wrinkling or folding during assembly of the light wavelength conversion sheet and handling, and if it exceeds 300 μm, the weight of the display and the thin film There is a risk that it may not be suitable. The more preferable lower limit of the thickness of the light-transmitting substrates 12 and 13 is 50 μm or more, and the more preferable upper limit is 200 μm or less.

  The thickness of the light transmissive base materials 12 and 13 is the cross section of the light transmissive base materials 12 and 13 using a scanning electron microscope (SEM), a transmission electron microscope (TEM), or a scanning transmission electron microscope (STEM). Is measured, and 20 thicknesses of the light-transmitting substrates 12 and 13 are measured in the cross-sectional image to obtain an average value of the film thicknesses at the 20 locations.

  Examples of constituent materials for the light-transmitting substrates 12 and 13 include polyester (for example, polyethylene terephthalate, polyethylene naphthalate), cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, polyamide, polyimide, polyethersulfone, and polysulfone. , Thermoplastic resins such as polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal, polyether ketone, polymethyl methacrylate, polycarbonate, or polyurethane. As a constituent material of the light-transmitting substrates 12 and 13, preferably, polyester (for example, polyethylene terephthalate, polyethylene naphthalate) is used.

  The light-transmitting substrates 12 and 13 may be composed of a single substrate, but may be a laminated substrate composed of a plurality of substrates. Such a laminated base material may be composed of a plurality of layers composed of the same kind of constituent raw material layers, or may be composed of a plurality of layers composed of different kinds of constituent raw material layers, depending on the application. Good.

<< light diffusion layer >>
The light diffusion layers 14 and 15 have a concavo-convex shape on the surface, and the light that enters and exits the light wavelength conversion sheet 10 can be diffused by the concavo-convex shape. By providing the light diffusion layers 14 and 15, the light wavelength conversion efficiency in the light wavelength conversion sheet 10 can be further increased. The light diffusion layers 14 and 15 contain light scattering particles and a binder resin.

<Light scattering particles>
The light-scattering particles in the light diffusion layers 14 and 15 are mainly for forming a concavo-convex shape on the surfaces of the light diffusion layers 14 and 15 and exhibiting a light-scattering function.

  The average particle size of the light-scattering particles in the light diffusion layers 14 and 15 is preferably 10 to 20,000 times the average particle size of the quantum dots 4 described above, and more preferably 10 to 5000 times. preferable. If the average particle size of the light-scattering particles is less than 10 times the average particle size of the quantum dots, sufficient light diffusibility may not be obtained in the light diffusion layer, and the average particle size of the light-scattering particles may be If it exceeds 20,000 times the average particle diameter of the quantum dots, the light diffusion performance of the light diffusion layer will be excellent, but the light transmittance of the light diffusion layer will be greatly reduced. In addition, the average particle diameter of light-scattering particle | grains can be measured by the method similar to the average particle diameter of the quantum dot mentioned above.

  Specifically, the average particle diameter of the light scattering particles in the light diffusion layers 14 and 15 is, for example, preferably 1 μm to 30 μm, and more preferably 1 μm to 20 μm. If the average particle diameter of the light scattering particles is less than 1 μm, the light wavelength conversion efficiency of the light wavelength conversion sheet may be insufficient, and the amount of light scattering particles added to provide sufficient light diffusibility. Need to be more. On the other hand, when the average particle diameter of the light scattering particles exceeds 30 μm, the light diffusion performance is excellent, but the light transmittance of the light diffusion layer is likely to be greatly reduced.

  The absolute value of the difference in refractive index between the light-scattering particles and the binder resin in the light diffusion layers 14 and 15 is preferably 0.02 or more and 0.15 or less. If it is less than 0.02, the light diffusibility due to the refractive index of the light scattering particles cannot be obtained optically, and the improvement of the light wavelength conversion efficiency of the light wavelength conversion sheet may be insufficient. If it exceeds 15, the transmittance of the light diffusion layer may be lowered. The more preferable lower limit of the difference in refractive index between the light-scattering particles and the binder resin is 0.03 or more, and the more preferable upper limit is 0.12. Note that either of the refractive index of the light-scattering particles and the refractive index of the binder resin may be larger. The refractive indexes of the light scattering particles and the binder resin can be measured by the same method as the refractive indexes of the light scattering particles 17 and the binder resin.

  Since the shape of the light-scattering particles in the light diffusion layers 14 and 15 is the same as the shape of the light-scattering particles 17 in the light wavelength conversion layer 11, description thereof will be omitted here. The light scattering particles in the light diffusion layers 14 and 15 are preferably chemically bonded to the binder resin from the viewpoint of firmly fixing the light scattering particles in the binder resin. This chemical bonding can be realized by using light scattering particles whose surface is modified with a silane coupling agent. Since the silane coupling agent is the same as the silane coupling agent described in the column of the light scattering particles in the light wavelength conversion layer, the description thereof is omitted here.

  The light scattering particles may be particles made of an organic material or particles made of an inorganic material. The organic material constituting the light scattering particles is not particularly limited. For example, polyester, polystyrene, melamine resin, (meth) acrylic resin, acrylic-styrene copolymer resin, silicone resin, benzoguanamine resin, benzoguanamine / formaldehyde condensation resin , Polycarbonate, polyethylene, polyolefin and the like. Of these, a crosslinked acrylic resin is preferably used. Moreover, it does not specifically limit as an inorganic material which comprises the said light-diffusion particle | grains, For example, inorganic oxides, such as a silica, an alumina, a titania, a tin oxide, an antimony dope tin oxide (ATO), a zinc oxide fine particle, etc. are mentioned. Of these, silica and / or alumina is preferably used.

<Binder resin>
As the binder resin of the light diffusion layers 14 and 15, a cured product of a polymerizable compound can be used. As the polymerizable compound, since the same compound as the polymerizable compound described in the column of the coat layer can be used, the description is omitted here.

<< Other light wavelength conversion sheet >>
As shown in FIG. 4, the light wavelength conversion sheet is a cured product of the light wavelength conversion composition, but is a light wavelength conversion sheet 20 including a light wavelength conversion layer 21 that does not include the light wavelength conversion particles 1. Also good. Since the light wavelength conversion sheet 20 is a cured product of the light wavelength conversion composition, the binder resin 3 contained in the light wavelength conversion layer 21 is the same as the binder resin 3 of the light wavelength conversion particles 1 and has a light wavelength. The quantum dots 4 included in the conversion layer 21 are the same as the quantum dots 4 of the light wavelength conversion particles 1.

<< Other light wavelength conversion sheet >>
As shown in FIG. 5, the light wavelength conversion sheet may be a light wavelength conversion sheet 30 having only the light wavelength conversion layer 11 (single layer structure). In addition, as shown in FIG. 6, the light wavelength conversion sheet may be a light wavelength conversion sheet 40 including a light wavelength conversion layer 11 and a light transmissive substrate 41 that supports the light wavelength conversion layer 11. . By providing the light transmissive substrate 31, the strength of the light wavelength conversion sheet can be increased more than that of the light wavelength conversion sheet 30.

<Light transmissive substrate>
As the light transmissive base material 41 of the light wavelength conversion sheet 40, the same material as the light transmissive base materials 12 and 13 can be used, and therefore the description thereof is omitted here.

<< Other light wavelength conversion sheet >>
As shown in FIGS. 7 and 8, the light wavelength conversion sheet is disposed on at least one surface side of the light wavelength conversion layer 11 and the light wavelength conversion layer 11 and integrated with the light wavelength conversion layer 11. The optical wavelength conversion sheet 50 provided with the optical member 51 may be sufficient.

<Optical member>
In this specification, the “optical member” means optical properties (for example, polarization, light refraction, light scattering, light reflectivity, light transmission, light absorption, light diffraction, optical rotation, etc.). It is not particularly limited as long as it is a sheet (film) -like or plate-like member having optical characteristics. Examples of the optical member include a lens sheet, an optical plate such as a light guide plate and a light diffusing plate, a reflective polarization separation sheet, and a polarizing plate. When the optical member sheet is provided on both sides of the light wavelength conversion sheet, the optical member may be an optical member having different optical characteristics. In the present embodiment, an example in which the optical member is a lens sheet will be described.

  As shown in FIGS. 7 and 8, the optical member 51 includes a light transmissive substrate 52 and a lens layer 53 provided on one surface of the light transmissive substrate 52. As shown in FIGS. 7 and 8, the lens layer 53 includes a sheet-like main body 54 and a plurality of unit lenses 55 arranged side by side on the light output side of the main body 54. The light transmissive substrate 52, the lens layer 53, the main body portion 54, and the unit lens 55 have the same configuration as a light transmissive base material 111, a lens layer 112, a main body portion 113, and a unit lens 114 described later. Therefore, the description is omitted here.

  In the light wavelength conversion sheet 50, the light wavelength conversion layer 11 and the optical member 51 are integrated by directly applying and curing the light wavelength conversion composition on one surface of the optical member 51. The light wavelength conversion layer 11 and the optical member 51 may be bonded together via an adhesive layer.

<< Other light wavelength conversion sheet >>
As shown in FIG. 9, the light wavelength conversion sheet may be a light wavelength conversion sheet 60 including a light wavelength conversion layer 11 and overcoat layers 61 and 62 that cover both surfaces of the light wavelength conversion layer 11. In this embodiment, the overcoat layers 61 and 62 are formed on both surfaces of the light wavelength conversion layer 11. However, if the overcoat layer is formed on at least one surface of the light wavelength conversion layer, the light wavelength conversion is performed. It does not need to be formed on both surfaces of the layer 11. In addition, when the overcoat layer is provided only on one surface of the light wavelength conversion layer, a light transmissive substrate may be provided on the other surface of the light wavelength conversion layer.

<Overcoat layer>
The overcoat layers 61 and 62 are layers made of a resin that covers the surface of the light wavelength conversion layer 11 and is formed by coating. Other layers such as a light diffusion layer may be formed on the overcoat layers 61 and 62.

  The overcoat layers 61 and 62 are provided to prevent the light wavelength conversion layer 11 from being directly exposed to the atmosphere. By providing such overcoat layers 61 and 62 on at least one surface of the light wavelength conversion layer 11, the quantum dots 4 can be further protected from moisture and oxygen, and the light transmissive substrate is converted to light wavelength. The thickness of the light wavelength conversion sheet can be made thinner than that provided on at least one surface of the layer 11.

  The overcoat layers 61 and 62 may have some function other than the function of preventing the light wavelength conversion layer 11 from being directly exposed to the atmosphere. Specifically, the overcoat layers 61 and 62 may be layers having at least one of functions such as anti-blocking properties, light diffusing properties, antistatic properties, and antireflection properties, for example. When the overcoat layers 61 and 62 are layers having a function of preventing the light wavelength conversion layer 11 from being directly exposed to the atmosphere and some other function, the overcoat layers 61 and 62 have a function for having a certain function. Materials may be added.

  The film thicknesses of the overcoat layers 61 and 62 are 0.1 μm or more and 100 μm or less from the viewpoint of preventing the light wavelength conversion layer 11 from being directly exposed to the atmosphere and reducing the thickness of the light wavelength conversion sheet. Is preferred. The film thickness of the overcoat layers 61 and 62 can be measured by the same method as the film thickness of the light wavelength conversion layer 11. The lower limit of the film thickness of the overcoat layers 61 and 62 is more preferably 1 μm or more, and the upper limit is more preferably 50 μm or less.

  The overcoat layers 61 and 62 preferably have a hardness that provides at least one of a vertical force of 10 μN or more and a horizontal force of −5 μN or less in a scratch test. When the overcoat layers 51 and 52 have such hardness, the overcoat layers 61 and 62 are dense films, and thus have a high ability to prevent the light wavelength conversion layer 11 from being exposed to the atmosphere. The vertical force and horizontal force in the scratch test are measured by using a nanoindentation device (product name “TI950 TriboIndenter”, manufactured by HYSITRON Co., Ltd.) from the cross section of the overcoat layer to the inside of the overcoat layer (Cube). Corner: Ti037_110410 (12)) is pushed in 50 nm, the depth is constant, and the average of vertical force (load) and horizontal force measured when this indenter is moved in the horizontal direction at a moving speed of 4 μm / min for 30 seconds. The average value of the five average values of the vertical force (5 times average value) and the average value of the five average values of the horizontal force (5 times average value) obtained by obtaining each value and repeating this scratch test 5 times. And The greater the value of the vertical force and the smaller the value of the horizontal force, the higher the hardness of the overcoat layers 61 and 52. From the viewpoint of enhancing the ability to prevent the light wavelength conversion layer 11 from being exposed to the atmosphere, the vertical force in the scratch test of the overcoat layers 61 and 62 is more preferably 15 μN or more, and the horizontal force is more preferably −8 μN or less. preferable.

  The overcoat layers 61 and 62 are not particularly limited as long as they have the above hardness. For example, a combination of a (meth) acrylate compound, an epoxy compound, an isocyanate and a polyol, a metal alkoxide, a silicon-containing resin, a water-soluble polymer, Alternatively, it can be formed using a composition for an overcoat layer containing a mixture thereof. Among these, from the viewpoint of preventing the light wavelength conversion layer 11 from being directly exposed to the atmosphere, the overcoat layers 61 and 62 are zinc acrylate, a hydrolysis product of alkoxysilane, polyvinyl alcohol, polysilazane, or these. It is preferable to form using the composition for overcoat layers containing a mixture.

In the light wavelength conversion sheets 20, 30, 40, 50, 60, the entire sheet may have a water vapor transmission rate of 0.1 g / (m ² · 24h) or more at 40 ° C. and a relative humidity of 90%. . In the light wavelength conversion sheets 20, 30, 40, 50, 60, the oxygen transmission rate at 23 ° C. and 90% relative humidity is 0.1 cm ³ / (m ² · 24 h · atm) or more in the entire sheet. May be. The water vapor transmission rate at 40 ° C. and 90% relative humidity in the light wavelength conversion sheets 20, 30, 40, 50, 60 may be 1 g / (m ² · 24 h) or more. The oxygen transmission rate at 23 ° C. and 90% relative humidity at 30, 40, 50, 60 may be 1 cm ³ / (m ² · 24 h · atm) or more.

<< Other light wavelength conversion sheet >>
The light wavelength conversion sheet may be a light wavelength conversion sheet 70 as shown in FIG. In this case, the water vapor transmission rate and the oxygen transmission rate of the light wavelength conversion sheet 70 may not be within the above-described ranges.

  The light wavelength conversion sheet 70 shown in FIG. 10 includes a light wavelength conversion layer 11, barrier films 71 and 72 provided on both surfaces of the light wavelength conversion layer 11, and the light wavelength conversion layer 11 side of the barrier films 71 and 72. Light diffusion layers 13 and 14 provided on the side opposite to the surface are provided. In the light wavelength conversion sheet 70, the surfaces of the light diffusion layers 13 and 14 constitute the surfaces 70 </ b> A and 70 </ b> B of the light wavelength conversion sheet 70.

<Barrier film>
The barrier films 71 and 72 are members for protecting the quantum dots 4 from moisture and oxygen by suppressing transmission of moisture and oxygen. Here, the “barrier film” in the present specification is a single member and has a water vapor transmission rate of less than 0.1 g / (m ² · 24 h) at 40 ° C. and a relative humidity of 90%, and at 23 ° C. and a relative humidity. A member whose oxygen permeability at 90% is less than 0.1 cm ³ / (m ² · 24 h · atm) is meant. The barrier film includes not only a single layer structure film but also a multilayer structure film. By installing the barrier films 71 and 72 in a state where the light wavelength conversion layer 11 is sandwiched, the heat resistance and heat resistance of the quantum dots 4 can be further improved. Barrier films 71 and 72 shown in FIG. 10 are provided on the light transmissive base materials 12 and 13 and the light wavelength conversion layer 11 side of the light transmissive base materials 12 and 13 and suppress the transmission of moisture and oxygen. Barrier layers 73 and 74 having functions.

The water vapor transmission rate (WVTR) of the barrier films 71 and 72 is 1.0 × 10 ⁻² g / (m ² · 24 h) or less at 40 ° C. and a relative humidity of 90%. Is more preferable. The water vapor transmission rate can be measured using a water vapor transmission rate measuring device (product name “PERMATRAN-W3 / 31”, manufactured by MOCON).

The oxygen transmission rate (OTR: Oxygen Transmission Rate) of the barrier films 71 and 72 is 1.0 × 10 ⁻² cm ³ / (m ² · 24 h · atm) or less at 23 ° C. and a relative humidity of 90%. More preferably it is. The oxygen permeability can be measured using an oxygen gas permeability measuring device (product name “OX-TRAN 2/21”, manufactured by MOCON).

(Barrier layer)
The barrier layers 73 and 74 are composed of a vapor deposition layer having a function of suppressing permeation of moisture and oxygen. A vapor deposition layer is a layer formed by vapor deposition methods, such as physical vapor deposition (PVD) methods, such as sputtering method and an ion plating method, and chemical vapor deposition (CVD) method, for example. A vapor deposition layer has the advantage that barrier property can be improved.

  The material for forming the vapor deposition layer is not particularly limited as long as it can be vapor-deposited by a vapor deposition method and has barrier properties, and examples thereof include inorganic oxides such as silicon oxide and aluminum oxide, metals, and the like.

  Although the film thickness of a vapor deposition layer is not specifically limited, It is preferable that they are 0.01 micrometer or more and 1 micrometer or less. If the thickness of the deposited layer is less than 0.01 μm, the barrier performance of the deposited layer may be insufficient, and if it exceeds 1 μm, the barrier performance may be easily deteriorated due to cracks in the deposited layer. is there. The minimum with more preferable thickness of a vapor deposition layer is 0.03 micrometer or more, and a more preferable upper limit is 0.5 micrometer or less.

  The film thickness of the vapor deposition layer is obtained by photographing a cross section of the light wavelength conversion sheet 60 using a scanning electron microscope (SEM), measuring the film thickness of the vapor deposition film at 20 positions in the image of the cross section, and measuring the film at the 20 positions. Use the average thickness. Moreover, a single layer may be sufficient as a vapor deposition layer, and what laminated | stacked the several layer may be sufficient as it. When a plurality of vapor deposition layers are laminated, each layer constituting the vapor deposition layer may be directly laminated or bonded.

  In the light wavelength conversion sheets 30, 40, 50, 60, 70, the light wavelength conversion layer 11 includes the light wavelength conversion particles 1, but does not include the light wavelength conversion particles in place of the light wavelength conversion layer 11, and You may use the light wavelength conversion layer which consists of a hardened | cured material of the said light wavelength conversion composition.

<<< Method for Producing Light Wavelength Conversion Sheet >>>
The light wavelength conversion sheet 10 can be produced as follows, for example. First, although not shown, a light diffusing layer composition containing light scattering particles and a polymerizable compound is applied to one surface of the light transmissive substrate 12 and dried to apply the light diffusing layer composition. A film is formed. Similarly, a coating film of the composition for light diffusion layer is formed on one surface of the light transmissive substrate 13.

  Subsequently, the coating film of the composition for light diffusion layers is hardened by light irradiation etc. Thus, as shown in FIG. 11A, the light diffusion layer 14 is formed on one surface of the light transmissive substrate 12, and the light transmissive substrate 12 with the light diffusion layer 14 is formed. Although not shown, the light transmissive substrate 13 with the light diffusion layer 15 is formed in the same manner.

  After forming the light transmissive substrate 13 with the light diffusing layer 15, as shown in FIG. 11B, the side opposite to the surface on the light diffusing layer 15 side of the light transmissive substrate 13 with the light diffusing layer 15. The optical wavelength conversion composition is applied to the surface, and dried to form a coating film 17 of the optical wavelength conversion composition.

  After the coating film 17 of the light wavelength conversion composition is formed, the surface opposite to the surface of the light diffusing layer 14 side in the light transmissive substrate 12 with the light diffusing layer 14 is the above light as shown in FIG. The light transmissive substrate 12 with the light diffusion layer 14 is disposed on the coating film 18 of the light wavelength conversion particle-containing composition so as to be in contact with the coating film 18 of the wavelength conversion particle-containing composition. Thereby, the coating film 18 of the light wavelength conversion particle-containing composition is sandwiched between the light-transmitting substrates 12 and 13.

  Next, as shown in FIG. 12B, the coating film 18 of the light wavelength conversion particle-containing composition is heated through the light-transmitting substrate 12, or the coating film 18 is irradiated with ionizing radiation, The light wavelength conversion particle-containing composition is cured to form the light wavelength conversion layer 11, and the light wavelength conversion layer 11, the light transmissive substrate 12 with the light diffusion layer 14, and the light transmission with the light diffusion layer 15. The base material 13 is integrated. Thereby, the light wavelength conversion sheet 10 shown in FIG. 2 is obtained.

  If the said light wavelength conversion composition is used instead of the said light wavelength conversion particle containing composition, the light wavelength conversion sheet 20 can be formed by the process similar to the light wavelength conversion sheet 10 after that.

  The light wavelength conversion sheets 30, 40, 60 can be manufactured, for example, as follows. First, the said light wavelength conversion particle containing composition is apply | coated on a base material (not shown), it is made to dry, and the coating film of a light wavelength conversion particle composition is formed. And the light wavelength conversion layer 11 is formed by applying heat to this coating film or irradiating ionizing radiation to cure the polymerizable compound. Thereafter, the substrate is peeled from the light wavelength conversion layer 11. Thereby, the light wavelength conversion sheet 30 shown in FIG. 5 is obtained. On the other hand, when the light transmissive base material 41 is used as the base material, the base material is left as it is without being peeled from the light wavelength conversion layer 11, so that the light wavelength conversion sheet 40 shown in FIG. can get. The light wavelength conversion sheet 60 shown in FIG. 9 is formed by coating the overcoat layer composition on at least one surface of the light wavelength conversion sheet 30 to form a coating film of the overcoat layer composition. Can be formed by curing. The light wavelength conversion sheet 60 can also be formed by the following method. First, the overcoat layer composition is applied to one surface of two substrates to form a coating film of the overcoat layer composition. After forming the coating film, the overcoat layer is formed by irradiating the coating film of each overcoat layer composition with ionizing radiation or applying heat. After the overcoat layer is formed, the light wavelength conversion particle-containing composition is applied onto the overcoat layer formed on one substrate to form a coating film of the light wavelength conversion particle-containing composition. Next, the other substrate is disposed on the coating film of the light wavelength conversion particle-containing composition so that the overcoat layer formed on the other substrate is in contact with the coating film of the light wavelength conversion particle-containing composition. Next, in this state, the coating film of the composition containing the light wavelength conversion particles is irradiated with ionizing radiation or heated to form a light wavelength conversion layer, and the light wavelength conversion layer and the overcoat layer are formed. Integrate. Finally, if both substrates are peeled off, the light wavelength conversion sheet 60 shown in FIG. 9 is obtained.

  The light wavelength conversion sheet 50 is formed by applying the light wavelength conversion particle-containing composition to one surface side of the optical member 51 and drying it to form a coating film of the light wavelength conversion particle-containing composition. And the light wavelength conversion layer 11 is formed by applying heat to this coating film or irradiating ionizing radiation to cure the polymerizable compound. Thereby, the light wavelength conversion sheet 50 shown in FIG. 7 is obtained.

  The light wavelength conversion sheet 70 includes a light diffusion layer 14, 15, a light transmissive substrate 12, 13, and a barrier layer 73, 74 formed on one surface of the light transmissive substrate 12, 13. If it forms in the films 71 and 72, it can be formed by the same process as the optical wavelength conversion sheet 10 later.

  The light wavelength conversion sheets 10, 20, 30, 40, 50, 60, and 70 can be used by being incorporated in a backlight device and an image display device. Hereinafter, an example in which the light wavelength conversion sheet 10 is incorporated in a backlight device and an image display device will be described. 13 is a schematic configuration diagram of an image display device including a backlight device according to the present embodiment, FIG. 14 is a perspective view of the lens sheet shown in FIG. 13, and FIG. It is sectional drawing along the II line. 16, FIG. 17, and FIG. 19 are schematic configuration diagrams of another backlight device according to the present embodiment, FIG. 18 is a schematic configuration diagram of the light source shown in FIG. 17, and FIG. 20 is shown in FIG. It is an enlarged view near the light incident surface of the optical plate. FIG. 21 is a schematic configuration diagram of another image display device according to the present embodiment, and FIG. 22 is an enlarged view of the vicinity of the color filter shown in FIG.

<<< Image display device >>>
An image display device 80 illustrated in FIG. 13 includes a backlight device 90 and a display panel 130 disposed on the light output side of the backlight device 90. The image display device 80 has a display surface 80A for displaying an image. In the image display device 80 shown in FIG. 13, the surface of the display panel 130 is the display surface 80A.

  The backlight device 90 illuminates the display panel 130 in a planar shape from the back side. The display panel 130 functions as a shutter that controls transmission or blocking of light from the backlight device 90 for each pixel, and is configured to display an image on the display surface 80A.

<< Display panel >>
A display panel 130 shown in FIG. 13 is a liquid crystal display panel, and is provided between a polarizing plate 131 disposed on the light incident side, a polarizing plate 132 disposed on the light output side, and between the polarizing plate 131 and the polarizing plate 132. The liquid crystal cell 133 is provided. Polarizing plates 131 and 132 decompose incident light into two linearly polarized light components (S-polarized light and P-polarized light) orthogonal to each other and vibrate in one direction (a direction parallel to the transmission axis) (for example, P It has a function of transmitting a linearly polarized component (for example, S-polarized light) that transmits polarized light and vibrates in the other direction (direction parallel to the absorption axis) perpendicular to the one direction.

  The liquid crystal cell 133 is mainly composed of a light transmissive substrate 134 such as a glass substrate, a color filter 135, and a liquid crystal layer 136 disposed between the light transmissive substrate 134 and the color filter 135. Yes.

  The color filter 135 includes a light-transmitting substrate 137 such as a glass substrate, a plurality of colored layers 138 provided on one surface side of the light-transmitting substrate 137, and a light-shielding layer provided between the colored layers 137. 139. The color filter 135 may further include an overcoat layer, a transparent electrode layer, an alignment film, an alignment protrusion, a columnar spacer, and the like.

  The colored layer 138 is made of a color material such as a pigment or a dye and a binder resin. The colored layer 138 is usually formed between the light shielding layers 138 on the light-transmitting substrate 137, and is composed of three types of colored layers having different colors.

<< Backlight device >>
A backlight device 90 shown in FIG. 13 is configured as an edge-light type backlight device, and includes a light source 100, an optical plate 105 as a light guide plate disposed on the side of the light source 100, and a light output side of the optical plate 105. The light wavelength conversion sheet 10 disposed on the lens, the lens sheet 110 disposed on the light output side of the light wavelength conversion sheet 10, the lens sheet 115 disposed on the light output side of the lens sheet 110, and the light output side of the lens sheet 115. The reflection-type polarization separation sheet 120 disposed and a reflection sheet 125 disposed on the side opposite to the light output side of the optical plate 105 are provided. The backlight device 90 includes the optical plate 105, the lens sheets 110 and 115, the reflective polarization separation sheet 120, and the reflective sheet 125, but these sheets and the like may not be provided. In the present specification, the “light exit side” means a side from which light is emitted from each member in the direction of exiting the backlight device.

  The backlight unit 90 has a light emitting surface 90A that emits light in a planar shape. In the backlight device 90 shown in FIG. 13, the light exit surface of the reflective polarization separation sheet 120 is the light emitting surface 90 </ b> A of the backlight device 90.

  The surface on the optical plate 105 side in the light wavelength conversion sheet 10 is a surface 10A (light incident surface), and the surface on the lens sheet 110 side in the light wavelength conversion sheet 10 is a surface 10B (light exit surface).

<Light source>
The light source 100 includes, for example, a fluorescent lamp such as a linear cold cathode tube, or a light emitter such as a point light emitting diode (LED) or an incandescent bulb. In the present embodiment, the light source 100 is composed of a large number of point-like light emitters, specifically, a large number of light emitting diodes (LEDs) arranged in a line on the light incident surface 95C side to be described later of the optical plate 105. ,It is configured.

  Since the light wavelength conversion sheet 10 is disposed in the backlight device 90, the light source 100 can use only a light emitter that emits light in a single wavelength region. For example, only a blue light emitting diode that emits blue light with high color purity can be used as the light source.

<Optical plate>
The optical plate 105 as the light guide plate is formed in a square shape in plan view. The optical plate 105 extends between a light exit surface 105A formed by one main surface on the display panel 130 side, a back surface 105B composed of the other main surface facing the light output surface 105A, and the light output surface 105A and the back surface 105B. And have side faces. Of the side surfaces, the side surface on the light source 100 side is a light incident surface 105 </ b> C that receives light from the light source 100. Light entering the optical plate 105 from the light incident surface 105C is guided through the optical plate in a direction (light guide direction) connecting the light incident surface 105C and the opposite surface opposite to the light incident surface 105C. The light is emitted from 105A.

<Lens sheet>
The lens sheets 110 and 115 have a function of changing the traveling direction of the incident light and emitting it from the light output side. In the present embodiment, as shown in FIG. 15, the function of concentratingly improving the brightness in the front direction by changing the traveling direction of the light L <b> 3 having a large incident angle and emitting it from the light exit side (condensing function). In addition, it has a function (retroreflection function) of reflecting the light L4 having a small incident angle and returning it to the light wavelength conversion sheet 10 side. The lens sheets 110 and 115 include a light transmissive substrate 111 and a lens layer 112 provided on one surface of the light transmissive substrate 111.

  When the surfaces 10A and 10B of the light wavelength conversion sheet 10 are uneven surfaces, the light exit surface 105A of the optical plate 105 is optically in close contact with a part (for example, a convex portion) of the surface 10A. 10A is preferably separated from other parts (for example, concave portions), and the light incident surface 110A of the lens sheet 110 is optically in close contact with a part (for example, convex portions) of the surface 10B, and the surface. It is preferable that it is separated from the other part (for example, recessed part) of 10B. In this case, the gap between the light exit surface 105A and the other part of the surface 10A and the gap between the light incident surface 110A and the other part of the surface 10B form an air layer. By providing the air layer, the light wavelength conversion sheet 10, the optical plate 105, and the lens sheet 110 are fixed so that the light exit surface 105A and the surface 10A and the light entrance surface 110A and the surface 10B are in optical contact. However, since it can suppress that the light wavelength conversion sheet 10, the optical plate 105, and the lens sheet 110 adhere, the interface between the light wavelength conversion sheet 10 and the optical plate 105, and the light wavelength conversion sheet 10 and the lens sheet 110 can be suppressed. It is possible to suppress the formation of wet-out at the interface between the two.

(Light transmissive substrate)
Since the light transmissive substrate 111 is the same as the light transmissive substrates 12 and 13, the description thereof will be omitted here.

(Lens layer)
As shown in FIGS. 14 and 15, the lens layer 112 includes a sheet-like main body 113 and a plurality of unit lenses 114 arranged side by side on the light output side of the main body 113.

  The main body 113 functions as a sheet-like member that supports the unit lens 114. As shown in FIGS. 14 and 15, the unit lenses 114 are arranged on the light output side surface 113 </ b> A of the main body 113 without leaving a gap. Therefore, the light exit surfaces 110B and 115B of the lens sheets 110 and 115 are formed by lens surfaces. On the other hand, as shown in FIG. 15, the main body 113 has a smooth surface that forms the light incident side surface of the lens layer 112 as the light incident side surface 113B that faces the light output side surface 113A.

  The unit lenses 114 are arranged side by side on the light exit side surface 113A of the main body 113. As shown in FIG. 14, the unit lenses 114 extend linearly in the direction intersecting the arrangement direction AD of the unit lenses 114, particularly linearly in the present embodiment. In the present embodiment, a large number of unit lenses 114 included in one lens sheet 110 and 115 extend in parallel to each other. Further, the longitudinal direction LD of the unit lenses 114 of the lens sheets 110 and 115 is orthogonal to the arrangement direction AD of the unit lenses 114 in the lens sheets 110 and 115.

  The unit lens 114 may have a triangular prism shape, a wavy shape, or a bowl shape such as a hemisphere. Specifically, examples of the unit lens include a unit prism, a unit cylindrical lens, and a unit microlens. Examples of the lens sheet having such a unit lens shape include a prism sheet, a lenticular lens sheet, and a microlens sheet. In the present embodiment, a triangular prism-shaped unit prism whose width becomes narrower toward the light output side will be described as a unit lens. The shape of the cross section (also referred to as the main cutting surface of the lens sheet) parallel to both the normal direction ND of the sheet surfaces of the lens sheets 110 and 115 and the arrangement direction AD of the unit lenses 114 is a triangular shape protruding to the light output side. ing. In particular, from the viewpoint of intensively improving the luminance in the front direction, the cross-sectional shape of the unit lens 114 in the main cut surface is an isosceles triangle shape, and the apex angle located between the equilateral sides is the light exit side surface 113A of the main body 113. Each unit lens 114 is configured to protrude from the light output side to the light output side.

  The unit lens 114 preferably has an apex angle of 80 ° or more and 100 ° or less, and more preferably an apex angle of about 90 °, from the viewpoint of improving the light utilization efficiency. However, considering the breakage of the tip of the unit lens during winding of the light wavelength conversion sheet, the tip of the unit lens 104 may be a curved surface.

  The dimensions of the lens sheets 110 and 115 can be set as follows as an example. First, as a specific example of the unit lenses 114, the arrangement pitch of the unit lenses 114 (corresponding to the width of the unit lenses 104 in the illustrated example) can be set to 10 μm or more and 200 μm or less. However, in recent years, the arrangement of the unit lenses 114 has been highly refined, and the arrangement pitch of the unit lenses 114 is preferably 10 μm or more and 50 μm or less. Further, the protruding height of the unit lens 114 from the main body 113 along the normal direction ND to the sheet surface of the lens sheets 110 and 115 can be set to 5 μm or more and 100 μm or less. Further, the apex angle θ of the unit lens 114 can be set to 60 ° or more and 120 ° or less.

  As can be understood from FIG. 13, the arrangement direction of the unit lenses 114 of the lens sheet 110 and the arrangement direction of the unit lenses 114 of the lens sheet 115 intersect, and more specifically, are orthogonal to each other.

<Reflection-type polarized light separation sheet>
The reflection-type polarization separation sheet 120 transmits only a first linearly polarized light component (for example, P-polarized light) out of the light emitted from the lens sheet 115 and is a second straight line orthogonal to the first linearly polarized light component. It has a function of reflecting a polarized light component (for example, S-polarized light) without absorbing it. In the state where the second linearly polarized light component reflected by the reflective polarization separation sheet 120 is reflected again and depolarized (including both the first linearly polarized light component and the second linearly polarized light component), The light again enters the reflective polarization separation sheet 120. Therefore, the reflective polarization separating sheet 120 transmits the first linearly polarized light component of the incident light again, and the second linearly polarized light component orthogonal to the first linearly polarized light component is reflected again. By repeating such a process, about 70 to 80% of the light emitted from the lens sheet 115 is emitted as the light source light that has become the first linearly polarized light component. Therefore, the wavelength conversion efficiency of the light wavelength conversion sheet 10 can be further increased by arranging the reflective polarization separation sheet 120. Therefore, further improvement in light utilization efficiency can be expected.

  As the reflective polarization separation sheet 120, “DBEF” (registered trademark) available from 3M Company can be used. In addition to “DBEF”, a high-intensity polarizing sheet “WRPS” available from Shinwha Intertek, a wire grid polarizer, or the like can be used as the reflective polarization separating sheet 90.

<Reflection sheet>
The reflection sheet 125 has a function of reflecting light leaking from the back surface 105 </ b> B of the optical plate 105 and making it enter the optical plate 105 again. The reflection sheet 125 includes a white scattering reflection sheet, a sheet made of a material having a high reflectance such as metal, a sheet containing a thin film (for example, a metal thin film) made of a material having a high reflectance as a surface layer, and the like. obtain. The reflection on the reflection sheet 125 may be regular reflection (specular reflection) or diffuse reflection. When the reflection on the reflection sheet 125 is diffuse reflection, the diffuse reflection may be isotropic diffuse reflection or anisotropic diffuse reflection.

<< Other backlight devices >>
The backlight device incorporating the light wavelength conversion sheet 10 may be a direct type backlight device as shown in FIG. The backlight device 140 shown in FIG. 16 includes a light source 100, an optical plate 141 that receives light from the light source 100 and functions as a light diffusing plate, and a light wavelength conversion sheet 10 that is disposed on the light output side of the optical plate 141. A lens sheet 110 disposed on the light output side of the light wavelength conversion sheet 10, a lens sheet 115 disposed on the light output side of the lens sheet 110, and a reflective polarization separation sheet 120 disposed on the light output side of the lens sheet 115. I have. In the present embodiment, the light source 100 is disposed not directly on the side of the optical plate 141 but directly below the optical plate 141. In FIG. 16, members denoted by the same reference numerals as those in FIG. 13 are the same as the members shown in FIG. Note that the backlight device 140 does not include the reflection sheet 125.

<Optical plate>
The optical plate 141 as a light diffusing plate is formed in a square shape in plan view. The optical plate 141 has a light incident surface 141A configured by one main surface on the light source 105 side and a light output surface 141B configured by the other main surface on the light wavelength conversion sheet 10 side. Light that enters the optical plate 141 from the light incident surface 141A is diffused in the optical plate 141 and is emitted from the light exit surface 141B.

<< Other backlight devices >>
The backlight device 90 shown in FIG. 13 includes the light wavelength conversion sheet 10, but the structure of the backlight device is not particularly limited as long as the light wavelength conversion member is included. For example, as illustrated in FIG. 17, the backlight device may be a backlight device 150 including a light source 160 instead of the light wavelength conversion sheet 10 and the light source 100. The light source 160 is one form of a light wavelength conversion member.

  As shown in FIG. 18, the light source 160 includes a substrate 161, a reflective member 162 having an opening 162 </ b> A disposed on the substrate 161, and a light emission disposed on the substrate 161 and in the opening 162 </ b> A of the reflective member 162. A light emitter 163 such as a diode, and an optical wavelength converter 164 filled in the opening 162A of the reflecting member 162 so as to cover the light emitter 163 are provided.

  The optical wavelength conversion unit 164 is different from the optical wavelength conversion layer 11 only in shape and location, and the configuration and physical properties of the optical wavelength conversion unit 164 are the same as those of the optical wavelength conversion layer 11. The light wavelength conversion part 164 is a cured product of a light wavelength conversion particle-containing composition containing the light wavelength conversion particles 1 and a polysiloxane compound having an epoxy compound or a silanol group and / or an alkoxysilyl group as a polymerizable compound. It is preferable. The light wavelength conversion part 164 can be formed by filling the opening 162A of the reflecting member 162 with the light wavelength conversion-containing composition and thermosetting the composition. In addition, when using the light source 160 which has the light wavelength conversion part 164, if the light wavelength conversion part 164 is arrange | positioned so that the light-emitting body 163 may be covered, a structure will not be specifically limited.

<< Other backlight devices >>
The backlight device may be the backlight device 170 shown in FIG. Specifically, the backlight device 170 shown in FIG. 19 includes a light-transmitting light wavelength conversion layer 180 disposed between the light source 100 and the optical plate 105 instead of the light wavelength conversion sheet 10. Yes. The light wavelength conversion layer 180 is a form of a light wavelength conversion member.

  The light wavelength conversion layer 180 is provided on the light incident surface 105C of the optical plate 105 as shown in FIG. The light wavelength conversion layer 180 is linearly arranged so that the longitudinal direction is along the arrangement direction of the light sources 90.

  The optical wavelength conversion layer 180 is different from the optical wavelength conversion layer 11 only in the arrangement location and shape, and the configuration and physical properties of the optical wavelength conversion layer 180 are the same as those of the optical wavelength conversion layer 11, and therefore the description thereof is omitted here. And

<< Other image display devices >>
The image display device may be the image display device 190 shown in FIG. Specifically, the image display device 190 illustrated in FIG. 21 includes a color filter 200 including a light wavelength conversion layer 201 instead of the color filter 135. Since the image display device 190 includes the color filter 200 including the light wavelength conversion layer 201, the light wavelength conversion sheet 10 is not provided. The color filter 200 is one form of a light wavelength conversion member.

  As shown in FIG. 21, the color filter 200 includes a light transmissive substrate 137 such as a glass substrate, a plurality of light wavelength conversion layers 201 provided on one surface side of the light transmissive substrate 137, And a light shielding layer 139 provided between the light wavelength conversion layers 201. The color filter 200 may further include an overcoat layer, a transparent electrode layer, an alignment film, alignment protrusions, columnar spacers, and the like.

<Light wavelength conversion layer>
As shown in FIG. 22, the light wavelength conversion layer 201 emits light of a color different from that of the first light wavelength conversion layer 201A and the light emitted from the first light wavelength conversion layer 201A. It is comprised from the optical wavelength conversion layer 201B. Specifically, the first light wavelength conversion layer 201A includes the first light wavelength conversion particles 1A including the first quantum dots 4A and not including the second quantum dots 4B, and the binder resin 16. The second light wavelength conversion layer 201B includes the second light wavelength conversion particles 1B including the second quantum dots 4B and not including the first quantum dots 4A, and the binder resin 16. . That is, the first light wavelength conversion layer 201A using the quantum dots that convert blue light into green light as the first quantum dots 4A and the quantum dots that convert blue light into red light as the second quantum dots 4B, When the second light wavelength conversion layer 201B is irradiated with blue light, blue light and green light are emitted from the first light wavelength conversion layer 201A, and blue light is emitted from the second light wavelength conversion layer 201B. And red light is emitted.

  The arrangement of the first light wavelength conversion layer 201A and the second light wavelength conversion layer 201B is not particularly limited. For example, a general arrangement such as a stripe type, a mosaic type, a triangle type, or a four-pixel arrangement type is used. be able to. Moreover, the width | variety, area, etc. of a colored layer can be set arbitrarily. For example, in FIG. 22, the first light wavelength conversion layer 201 </ b> A and the second light wavelength conversion layer 201 </ b> B are alternately arranged via the light shielding layer 139.

(Light wavelength conversion particles)
The first light wavelength conversion particle 1A includes the first quantum dot 4A and does not include the second quantum dot 4B, and the first light wavelength conversion particle 1B includes the second quantum dot 4A. Since it is the same as the light wavelength conversion particle 1 except that it does not include the first quantum dot 4A, the description is omitted here.

(Binder resin)
The binder resin 16 in the first light wavelength conversion layer 201 </ b> A and the second light wavelength conversion layer 201 </ b> B is composed of a cured product of a polymerizable compound in the same manner as the binder resin 16 described in the column of the light wavelength conversion layer 11. However, from the viewpoint of patterning the light wavelength conversion layer, the polymerizable compound is preferably an alkali-soluble resin.

  It is considered that the reason why the quantum dots are easily deteriorated by the heat resistance test or the heat and humidity resistance test is as follows. First, as described above, a ligand composed of a sulfur compound, a phosphorus compound, or the like is coordinated on the surface of the quantum dot, and this ligand is easily detached by light or heat. When the ligand is detached from the quantum dot, moisture and oxygen are likely to adhere to the quantum dot, and the quantum dot is oxidized and deteriorated. Thereby, it is thought that a quantum dot will deteriorate by a heat resistance test or a heat-and-moisture resistance test. On the other hand, in this embodiment, the binder resin 3 of the light wavelength conversion particle 1 or the binder resin 3 of the light wavelength conversion layer 21 is a reaction product (cured) of a compound having a heterocyclic group containing an oxygen atom and a thiol compound. Therefore, heat resistance and heat-and-moisture resistance can be improved. This is because the sulfur component present in the binder resin assists the role of the ligand even when the ligand is detached from the quantum dot (for example, the ligand binds to the quantum dot instead of the ligand, In addition, the component derived from the compound having a heterocyclic group containing an oxygen atom improves the water resistance, so that the deterioration of the quantum dots can be achieved. This is considered to be suppressed. In addition, since the 1st light wavelength conversion particle | grains 1A and the 2nd light wavelength conversion particle | grains 1B also contain the binder resin 3, it can improve heat resistance and heat-and-moisture resistance from the same reason.

  When the thiol compound is simply contained without being fixed in the binder resin of the light wavelength conversion particles or the binder resin of the light wavelength conversion layer, the thiol compound is easily detached from the binder resin. In particular, when the light wavelength conversion particles are dispersed in a dispersion medium, the thiol compound is easily detached by elution from the binder resin. On the other hand, in this embodiment, the binder resin 3 of the light wavelength conversion particle 1 or the binder resin 3 of the light wavelength conversion layer 21 is a reaction product (cured) of a compound having a heterocyclic group containing an oxygen atom and a thiol compound. Therefore, a sulfur component derived from a thiol compound is fixed in the binder resin 3. Thereby, the deterioration suppression effect of the quantum dot 4 can be acquired stably.

  When quantum dots are encapsulated in glass particles, they can suppress the ingress of moisture and oxygen, but they are fragile, so defects due to cracks are likely to occur during manufacturing, processing, or heat and moisture resistance tests. It is difficult to obtain light wavelength conversion particles having stable quality. On the other hand, since the light wavelength conversion particle 1 in the present embodiment includes the quantum dots 4 in the binder resin 3, it has excellent flexibility and can suppress defects due to cracks. Thereby, the light wavelength conversion particle | grains 1 which have stable quality can be provided.

  According to this embodiment, since the deterioration of the quantum dots 4 can be suppressed by the binder resin 3 of the light wavelength conversion particles 1 and the binder resin 3 of the light wavelength conversion layer 21, the light wavelength conversion sheets 10, 20, 30, 40, 50 , 60, the barrier film can be omitted. Thereby, while being able to simplify the process of a light wavelength conversion sheet, it becomes easy to improve quality, and thickness reduction of a light wavelength conversion sheet can be achieved.

  In a light wavelength conversion sheet provided with a barrier film, when a heat resistance test or a moist heat resistance test is performed, point-like defects such as pinholes and cracks are likely to occur in the barrier film. When a defect part is generated in the barrier film, moisture or oxygen enters from the defect part, and some quantum dots are deteriorated, and there is a possibility that a part (luminance defect) in which the luminance is reduced in a dot shape in the light wavelength conversion sheet is generated. . This dot-like luminance defect is more visible than the case where the quantum dots deteriorate as a whole and the luminance decreases uniformly. On the other hand, according to the present embodiment, the deterioration of the quantum dots 4 can be suppressed by the binder resin 3 of the light wavelength conversion particles 1 and the binder resin 3 of the light wavelength conversion layer 21. Even when a portion is generated and moisture or oxygen enters from the defective portion, the point-like luminance defect can be suppressed.

  According to this embodiment, since the deterioration of the quantum dots 4 can be suppressed by the binder resin 3 of the light wavelength conversion particles 1 and the binder resin 3 of the light wavelength conversion layer 11, the light wavelength conversion sheets 10, 20, 30, 40, 50 60, 70, it is possible to suppress the deterioration of the quantum dots 4 existing in the peripheral portions 10C, 20A, 30A, 40A, 50A, 60A, 70C.

  In the light wavelength conversion sheet 50, the light wavelength conversion layer 11 and the optical member 51 are integrated. Therefore, the light wavelength conversion sheet 50 is simplified and thin compared to the case where the light wavelength conversion sheet and the optical member are separately disposed. A backlight device can be obtained. That is, when the light wavelength conversion sheet and the optical member are separately arranged, there is an air interface between the light wavelength conversion sheet and the optical member, so that a relatively large gap is formed in the backlight device. Cost. On the other hand, in this embodiment, since the light wavelength conversion layer 11 and the optical member 51 are integrated, there is no air interface between the light wavelength conversion layer 11 and the optical member 51. Thereby, a simplified thin backlight device can be obtained.

  Light emitters such as light emitting diodes also generate heat during light emission. For this reason, normally, when the light wavelength conversion part is incorporated in the light source or when the light wavelength conversion member is disposed at a position close to the light source, the light wavelength conversion part is covered to suppress the deterioration of the quantum dots. A barrier member is required. On the other hand, in this embodiment, the heat resistance and wet heat resistance in the light wavelength conversion part 164 can be improved by the binder resin 3 of the light wavelength conversion particle 1 in the light wavelength conversion part 164 or the light wavelength conversion line layer 180. Therefore, the deterioration of the quantum dots 4 can be suppressed without covering the light wavelength conversion unit 164 and the light wavelength conversion layer 180 with a barrier member.

  Conventionally, light that has been wavelength-converted by the quantum dots emitted from the light wavelength conversion sheet is condensed on the light output side of the light wavelength conversion sheet, and light that has not been wavelength-converted by the light wavelength conversion sheet is converted to the light wavelength conversion sheet. It has been studied to increase the optical wavelength conversion efficiency by arranging a lens sheet to be returned to the side. However, the optical wavelength conversion efficiency is not sufficient only by arranging such a lens sheet, and further improvement of the optical wavelength conversion efficiency is desired. According to this embodiment, when the external haze value of the light wavelength conversion sheet 10 is smaller than the internal haze value of the light wavelength conversion sheet 10, the light wavelength conversion efficiency can be further improved. That is, since the light emitted from the light source has straightness, the light that enters the light wavelength conversion sheet and is not wavelength-converted by the quantum dots, and the light emitted from the light wavelength conversion sheet also has straightness. Yes. Here, when the external haze value of the light wavelength conversion sheet is high, light that has not been wavelength-converted that has straightness on the surface of the light wavelength conversion sheet is refracted, and light that is not wavelength-converted emitted from the light wavelength conversion sheet In this case, a component having a large emission angle increases. On the other hand, a lens sheet having a condensing function and a retroreflective function tends to make the lens sheet retroreflected more easily as the incident angle to the lens sheet is smaller. That is, there is a tendency that light having a larger incident angle to the lens sheet is more easily transmitted through the lens sheet. In the present embodiment, since the external haze value is smaller than the internal haze value in the light wavelength conversion sheet 10, even if light that has not undergone wavelength conversion is refracted on the surface of the light wavelength conversion sheet 10, it is emitted. The light can be emitted in a state where the angle is small. Accordingly, in the light which is emitted from the light wavelength conversion sheet 10 and is not wavelength-converted, a component having a small emission angle can be increased. Therefore, the lens sheet 100 can retroreflect the light emitted from the light wavelength conversion sheet without wavelength conversion and return it to the light wavelength conversion sheet 10 side, so that the opportunities for wavelength conversion increase. Moreover, since the internal haze value is larger than the external haze value, the light path length is increased by scattering light within the light wavelength conversion sheet, and the opportunity for wavelength conversion is further increased. Thereby, the optical wavelength conversion efficiency can be improved. Since the quantum dots 4 emit light isotropically, the light wavelength-converted by the quantum dots 4 is directed in various directions, and when reaching the surface of the light wavelength conversion sheet 10, the surface of the light wavelength conversion sheet is further increased. The light is refracted and wavelength-converted light becomes light with a large angle and is easily emitted from the optical wavelength conversion sheet. For this reason, the wavelength-converted light is relatively easily transmitted through the lens sheet 110.

  In the above description, the light diffusion characteristics (external diffusion characteristics) on the surface of the light wavelength conversion sheet are expressed using the external haze value for the following reason. First, the light diffusion characteristics of the light wavelength conversion sheet can be evaluated by measuring the light intensity of the transmitted light for each angle with a known goniophotometer such as a goniophotometer. It is extremely difficult to define the light diffusion characteristics of the light wavelength conversion sheet using the result of the light intensity. On the other hand, as described above, in the definition of haze, transmitted light deviated by 2.5 ° or more with respect to incident light is measured as haze. Not measured. As described above, as the haze, transmitted light of less than 2.5 ° with respect to the incident light is not measured. However, as described above, light having a large incident angle to the lens sheet, that is, transmitted light having a large emission angle in the light wavelength conversion sheet is generated. Since this is a problem, it is important how much transmitted light deviates by 2.5 ° or more from incident light by less than 2.5 °. For this reason, the light diffusion characteristic of the light wavelength conversion sheet can be expressed by the magnitude of the haze value of the light wavelength conversion sheet without measuring the light intensity for each angle of transmitted light by a goniophotometer. On the other hand, since it is necessary to consider that light is refracted on the surface of the light wavelength conversion sheet and the emission angle becomes large, an external haze is used to express the light diffusion characteristics on the surface of the light wavelength conversion sheet. Values were used.

  According to this embodiment, since the light wavelength conversion layer 11 includes the light scattering particles 17, the light wavelength conversion efficiency can be further improved. Therefore, for example, a light source that emits blue light is used as the light source 100, a quantum dot that converts blue light into green light is used as the first quantum dot 4A, and blue light is converted into red light as the second quantum dot 4B. When the light wavelength conversion sheet containing quantum dots is irradiated with blue light, the chromaticity x and y can be increased compared to a light wavelength conversion sheet that does not contain light scattering particles, and white light or a color close to white The light of taste can be obtained.

  According to this embodiment, since the light wavelength conversion layer 11 includes the light scattering particles 17, green light emission can be preferentially enhanced over red light emission. The reason for this is not clear, but the light-scattering particles appear to inhibit energy transfer from the first quantum dot that converts blue light to green light to the second quantum dot that converts blue light to red light. This is probably because the green light emission that was originally deactivated by the above-described energy transfer does not deactivate, and thus reaches the light emission process, and as a result, the green light emission increases.

  In order to describe the present invention in detail, examples will be described below, but the present invention is not limited to these descriptions.

<< Adjustment of light wavelength conversion composition >>
Each component was mix | blended so that it might become a composition shown below, and the light wavelength conversion composition was obtained.
<Example 1>
(Light wavelength conversion composition 1)
-Bisphenol A type epoxy resin (product name "jER828", manufactured by Mitsubishi Chemical Corporation): 50 parts by mass-Tetraethylene glycol bis (3-mercaptopropionate) (product name "EGMP-4", manufactured by SC Organic Chemical Co., Ltd.) : 50 parts by mass-epoxy curing accelerator (product name "U-CAT SA 102", manufactured by San Apro): 1 part by mass-green light emitting quantum dots (product name "CdSe / ZnS 530", manufactured by SIGMA-ALDRICH, core : CdSe, shell: ZnS, average particle size 3.3 nm): 0.2 parts by mass / red light emitting quantum dot (product name “CdSe / ZnS 610”, manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average Particle size 5.2 nm): 0.2 parts by mass

<Example 2>
(Light wavelength conversion composition 2)
-Bisphenol A type epoxy resin (product name "jER828", manufactured by Mitsubishi Chemical Corporation): 50 parts by mass-Tetraethylene glycol bis (3-mercaptopropionate) (product name "EGMP-4", manufactured by SC Organic Chemical Co., Ltd.) : 50 parts by mass-epoxy curing accelerator (product name "U-CAT SA 102", manufactured by San Apro): 1 part by mass-green light emitting quantum dots (product name "CdSe / ZnS 530", manufactured by SIGMA-ALDRICH, core : CdSe, shell: ZnS, average particle size 3.3 nm): 0.2 parts by mass / red light emitting quantum dot (product name “CdSe / ZnS 610”, manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average Particle size: 5.2 nm): 0.2 parts by mass Alumina particles (light scattering particles, product name “DAM-03”, manufactured by Denki Kagaku Kogyo Co., Ltd. Average particle diameter 4 μm): 10 parts by mass

<Example 3>
(Light wavelength conversion composition 3)
・ Hydrogenated epoxy resin (product name “jER YX8000”, manufactured by Mitsubishi Chemical Corporation): 50 parts by mass ・ Tetraethylene glycol bis (3-mercaptopropionate) (product name “EGMP-4”, manufactured by SC Organic Chemical Co., Ltd.) : 50 parts by mass-epoxy curing accelerator (product name "U-CAT SA 102", manufactured by San Apro): 1 part by mass-green light emitting quantum dots (product name "CdSe / ZnS 530", manufactured by SIGMA-ALDRICH, core : CdSe, shell: ZnS, average particle size 3.3 nm): 0.2 parts by mass / red light emitting quantum dot (product name “CdSe / ZnS 610”, manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average Particle size 5.2 nm): 0.2 parts by mass

<Example 4>
(Light wavelength conversion composition 4)
-Bisphenol A type epoxy resin (product name "jER828", manufactured by Mitsubishi Chemical Corporation): 50 parts by mass-Pentaerythritol tetrakis (3-mercaptobutyrate) (product name "Karenz MT PE1", manufactured by Showa Denko KK): 50 masses Part / epoxy curing accelerator (product name “U-CAT SA 102”, manufactured by San Apro): 1 part by mass / green light emitting quantum dot (product name “CdSe / ZnS 530”, manufactured by SIGMA-ALDRICH, core: CdSe, Shell: ZnS, average particle size 3.3 nm): 0.2 parts by mass. Red light emitting quantum dots (product name “CdSe / ZnS 610”, manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 5) .2 nm): 0.2 parts by mass

<Example 5>
(Light wavelength conversion composition 5)
First, 63 parts by mass of methyl methacrylate (MMA), 12 parts by mass of acrylic acid (AA), 6 parts by mass of 2-hydroxyethyl methacrylate (HEMA), and 88 parts by mass of diethylene glycol dimethyl ether (DMDG) in the polymerization tank. After the parts were charged, stirred and dissolved, 7 parts by mass of 2,2′-azobis (2-methylbutyronitrile) was added and dissolved uniformly. Then, it stirred at 85 degreeC under nitrogen stream for 2 hours, and also was made to react at 100 degreeC for 1 hour. 7 parts by mass of glycidyl methacrylate (GMA), 0.4 parts by mass of triethylamine, and 0.2 parts by mass of hydroquinone were further added to the resulting solution, and the mixture was stirred at 100 ° C. for 5 hours to obtain an ethylenically unsaturated group. An alkali-soluble resin solution 1 having a solid content (solid content 50%) was obtained.

Next, a curable resin composition 1 having the following composition was obtained using the alkali-soluble resin solution 1.
(Curable resin composition 1)
Alkali-soluble resin solution 1 (solid content 50%): 58 parts by mass Dipentaerythritol pentaacrylate (product name “SR399”, manufactured by Sartomer): 17 parts by mass Polymerization initiator (product name “Irgacure (registered trademark)” 907 ", manufactured by BASF Japan Ltd.): 4 parts by mass, diethylene glycol dimethyl ether: 21 parts by mass

And each component was mix | blended so that it might become a composition shown below, and the light wavelength conversion composition 5 was obtained.
(Light wavelength conversion composition 5)
Tetraethylene glycol bis (3-mercaptopropionate) (product name “EGMP-4”, manufactured by SC Organic Chemical Co., Ltd.): 10 parts by mass Curable resin composition 1 (solid content 50%): 20 parts by mass Green light-emitting quantum dots (product name “CdSe / ZnS 530”, manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 3.3 nm): 0.04 parts by mass / acetic acid-3-methoxybutyl: 70 Parts by mass

<Example 6>
(Light wavelength conversion composition 6)
Tetraethylene glycol bis (3-mercaptopropionate) (product name “EGMP-4”, manufactured by SC Organic Chemical Co., Ltd.): 10 parts by mass Curable resin composition 1 (solid content 50%): 20 parts by mass Red light emitting quantum dot (product name “CdSe / ZnS 610”, manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 5.2 nm): 0.04 parts by mass / acetic acid-3-methoxybutyl: 70 Parts by mass

<Example 7>
(Light wavelength conversion composition 7)
-Bisphenol A type epoxy resin (product name "jER828", manufactured by Mitsubishi Chemical Corporation): 50 parts by mass-Tetraethylene glycol bis (3-mercaptopropionate) (product name "EGMP-4", manufactured by SC Organic Chemical Co., Ltd.) : 50 parts by mass-epoxy curing accelerator (product name "(2,4,6-tris (dimethylaminomethyl) phenol)", manufactured by Tokyo Chemical Industry Co., Ltd.): 1 part by mass-green light emitting quantum dot (product name "CdSe / ZnS 530 ", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 3.3 nm): 1.0 part by mass, red light emitting quantum dots (product name" CdSe / ZnS 610 ", SIGMA-ALDRICH Co., Ltd., core: CdSe, shell: ZnS, average particle size 5.2 nm): 1.0 part by mass

<Example 8>
(Light wavelength conversion composition 8)
・ Hydrogenated epoxy resin (product name “jER YX8000”, manufactured by Mitsubishi Chemical Corporation): 50 parts by mass ・ Tetraethylene glycol bis (3-mercaptopropionate) (product name “EGMP-4”, manufactured by SC Organic Chemical Co., Ltd.) : 50 parts by mass-epoxy curing accelerator (product name "(2,4,6-tris (dimethylaminomethyl) phenol)", manufactured by Tokyo Chemical Industry Co., Ltd.): 1 part by mass-green light emitting quantum dot (product name "CdSe / ZnS 530 ", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 3.3 nm): 1.0 part by mass, red light emitting quantum dots (product name" CdSe / ZnS 610 ", SIGMA-ALDRICH Co., Ltd., core: CdSe, shell: ZnS, average particle size 5.2 nm): 1.0 part by mass

<Example 9>
(Light wavelength conversion composition 9)
Bisphenol A type epoxy resin (product name “jER828”, manufactured by Mitsubishi Chemical Corporation): 50 parts by mass Pentaerythritol tetrakis (3-mercaptobutyrate) (product name “Karenz MT PE1”, manufactured by Showa Denko KK): 50 parts by mass・ Epoxy curing accelerator (Product name “(2,4,6-Tris (dimethylaminomethyl) phenol)”, manufactured by Tokyo Chemical Industry Co., Ltd.): 1 part by mass ・ Green light emitting quantum dot (Product name “CdSe / ZnS 530”) , Manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 3.3 nm): 1.0 part by mass, red light emitting quantum dot (product name “CdSe / ZnS 610”, manufactured by SIGMA-ALDRICH, core : CdSe, shell: ZnS, average particle size 5.2 nm): 1.0 part by mass

<Example 10>
(Light wavelength conversion composition 10)
-Bisphenol A type epoxy resin (product name "jER828", manufactured by Mitsubishi Chemical Corporation): 50 parts by mass-Tetraethylene glycol bis (3-mercaptopropionate) (product name "EGMP-4", manufactured by SC Organic Chemical Co., Ltd.) : 50 parts by mass-epoxy curing accelerator (product name "(2,4,6-tris (dimethylaminomethyl) phenol)", manufactured by Tokyo Chemical Industry Co., Ltd.): 1 part by mass-green light emitting quantum dot (product name "CdSe / ZnS 530 ", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 3.3 nm): 1.0 part by mass

<Example 11>
(Light wavelength conversion composition 11)
-Bisphenol A type epoxy resin (product name "jER828", manufactured by Mitsubishi Chemical Corporation): 50 parts by mass-Tetraethylene glycol bis (3-mercaptopropionate) (product name "EGMP-4", manufactured by SC Organic Chemical Co., Ltd.) : 50 parts by mass / epoxy curing accelerator (product name “(2,4,6-tris (dimethylaminomethyl) phenol)”, manufactured by Tokyo Chemical Industry Co., Ltd.): 1 part by mass / red light emitting quantum dot (product name “CdSe / ZnS 610 ", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 5.2 nm): 1.0 part by mass

<Comparative Example 1>
(Light wavelength conversion composition 12)
・ Bisphenol A type epoxy resin (product name “jER828”, manufactured by Mitsubishi Chemical Corporation): 50 parts by mass ・ Epoxy resin curing agent (product name “Ricacid MH-700”, manufactured by Shin Nippon Rika Co., Ltd.): 50 parts by mass Accelerator (product name “U-CAT SA 102”, manufactured by San Apro): 1 part by mass / green light emitting quantum dot (product name “CdSe / ZnS 530”, manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, (Average particle size 3.3 nm): 0.2 parts by mass / red light emitting quantum dot (product name “CdSe / ZnS 610”, manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 5.2 nm): 0.2 parts by mass

<Comparative example 2>
(Light wavelength conversion composition 13)
Curable resin composition 1 (solid content 50%): 40 parts by mass Green emitting quantum dot (product name “CdSe / ZnS 530”, manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 3 .3 nm): 0.2 parts by mass / 3-methoxybutyl acetate: 60 parts by mass

<Comparative Example 3>
(Light wavelength conversion composition 14)
Curable resin composition 1 (solid content 50%): 40 parts by mass Red emitting quantum dot (product name “CdSe / ZnS 610”, manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 5 0.2 nm): 0.2 parts by mass / 3-methoxybutyl acetate: 60 parts by mass

<Comparative Example 4>
(Light wavelength conversion composition 15)
・ Bisphenol A type epoxy resin (product name “jER828”, manufactured by Mitsubishi Chemical Corporation): 50 parts by mass ・ Epoxy resin curing agent (product name “Ricacid MH-700”, manufactured by Shin Nippon Rika Co., Ltd.): 50 parts by mass Accelerator (product name “(2,4,6-tris (dimethylaminomethyl) phenol)”, manufactured by Tokyo Chemical Industry Co., Ltd.): 1 part by mass / green light emitting quantum dot (product name “CdSe / ZnS 530”, SIGMA- Manufactured by ALDRICH, core: CdSe, shell: ZnS, average particle size 3.3 nm): 1.0 part by mass, red light emitting quantum dot (product name “CdSe / ZnS 610”, manufactured by SIGMA-ALDRICH, core: CdSe, Shell: ZnS, average particle size 5.2 nm): 1.0 part by mass

<Comparative Example 5>
(Light wavelength conversion composition 16)
・ Bisphenol A type epoxy resin (product name “jER828”, manufactured by Mitsubishi Chemical Corporation): 50 parts by mass ・ Epoxy resin curing agent (product name “Ricacid MH-700”, manufactured by Shin Nippon Rika Co., Ltd.): 50 parts by mass Accelerator (product name “(2,4,6-tris (dimethylaminomethyl) phenol)”, manufactured by Tokyo Chemical Industry Co., Ltd.): 1 part by mass / green light emitting quantum dot (product name “CdSe / ZnS 530”, SIGMA- Manufactured by ALDRICH, core: CdSe, shell: ZnS, average particle size 3.3 nm): 1.0 part by mass

<Comparative Example 6>
(Light wavelength conversion composition 17)
・ Bisphenol A type epoxy resin (product name “jER828”, manufactured by Mitsubishi Chemical Corporation): 50 parts by mass ・ Epoxy resin curing agent (product name “Ricacid MH-700”, manufactured by Shin Nippon Rika Co., Ltd.): 50 parts by mass Accelerator (product name “(2,4,6-tris (dimethylaminomethyl) phenol)”, manufactured by Tokyo Chemical Industry Co., Ltd.): 1 part by mass / red light emitting quantum dot (product name “CdSe / ZnS 610”, SIGMA- Manufactured by ALDRICH, core: CdSe, shell: ZnS, average particle size 5.2 nm): 1.0 part by mass

<< Manufacture of light wavelength conversion particles >>
Light wavelength conversion particles were obtained according to the following procedure.
<Example 12>
(Light wavelength conversion particle 1)
First, the light wavelength conversion composition 7 is charged into a polymerization vessel having a stirrer, and 10 parts by mass of polyvinyl alcohol as a dispersant is dissolved in 900 parts by mass of ion-exchanged water as a poor solvent. I put it in. Then, it stirred for 10 minutes with the stirring speed of 400 rpm with the stirring apparatus, and the light wavelength conversion composition 7 was finely dispersed as a droplet in a poor solvent. Subsequently, stirring by the stirring device is continued at a stirring speed of 400 rpm, the temperature of the reaction solution containing the light wavelength conversion composition 7 and the poor solvent is increased to 60 ° C., and the temperature of the reaction solution is 60 ° C. Suspension polymerization was performed over 3 hours, and then the temperature of the reaction solution was raised to 80 ° C., and the reaction solution was stirred at a temperature of 80 ° C. for 3 hours to obtain a particulate polymer. . Thereafter, the reaction solution containing the polymer in the polymerization vessel was cooled to room temperature while stirring with a stirrer. Next, the reaction solution was suction filtered, and the filtration residue was washed with ion-exchanged water and then drained to obtain light wavelength conversion particles 1. In the light wavelength conversion particles 1, green light emission quantum dots and red light emission quantum dots were encapsulated in the resin particles, and the average particle diameter of the light wavelength conversion particles 1 was 0.5 μm. The average particle diameter of the light wavelength conversion particles 1 was determined by measuring the particle diameter of 20 light wavelength conversion particles 1 with a transmission electron microscope and calculating the average value. In addition, the average particle diameter of the following light wavelength conversion particles 2-9 was calculated | required with the method similar to the light wavelength conversion particle 1.

<Example 13>
(Light wavelength conversion particle 2)
In order to form a coating layer on the surface of the light wavelength conversion particle 1, 30 parts by mass of tricyclodecane dimethanol diacrylate (product name “A-DCP”, manufactured by Shin-Nakamura Chemical Co., Ltd.), and a radical polymerization initiator (2, Coat layer composition 1 containing 0.3 parts by mass of 2′-azobis (2,4-dimethylvaleronitrile), manufactured by Tokyo Chemical Industry Co., Ltd. is added to the reaction solution before suction filtration in Example 10 for coating layer use. The temperature of this reaction liquid containing the composition 1 was raised to 60 ° C., and suspension polymerization was performed for 3 hours while the temperature of the reaction liquid was 60 ° C. Thereafter, in order to completely deactivate the radical initiator, the temperature of the reaction solution was raised to 80 ° C., and the reaction solution was stirred at a temperature of 80 ° C. for 3 hours to form a coating layer on the surface. A particulate polymer was obtained. Thereafter, the reaction solution containing the polymer in the polymerization vessel was cooled to room temperature while stirring with a stirrer. Next, the reaction solution was suction filtered, and the filtration residue was washed with ion-exchanged water and then drained to obtain light wavelength conversion particles 2. In the light wavelength conversion particles 2, green light emission quantum dots and red light emission quantum dots were included in the binder resin, and the average particle diameter of the light wavelength conversion particles 2 was 0.9 μm.

<Example 14>
(Light wavelength conversion particle 3)
A light wavelength conversion particle 3 was obtained by the same procedure as the light wavelength conversion particle 1 except that the light wavelength conversion composition 8 was used instead of the light wavelength conversion composition 7. In the light wavelength conversion particles 3, green light emission quantum dots and red light emission quantum dots were included in the binder particles, and the average particle diameter of the light wavelength conversion particles 3 was 0.5 μm.

<Example 15>
(Light wavelength conversion particle 4)
A light wavelength conversion particle 4 was obtained by the same procedure as the light wavelength conversion particle 1 except that the light wavelength conversion composition 9 was used instead of the light wavelength conversion composition 7. In the light wavelength conversion particles 4, green light emission quantum dots and red light emission quantum dots were included in the binder particles, and the average particle diameter of the light wavelength conversion particles 4 was 0.5 μm.

<Example 16>
(Light wavelength conversion particle 5)
A light wavelength conversion particle 5 was obtained by the same procedure as that of the light wavelength conversion particle 1 except that the light wavelength conversion composition 10 was used instead of the light wavelength conversion composition 7. In the light wavelength conversion particles 5, green light emitting quantum dots are included in the binder particles, and the average particle diameter of the light wavelength conversion particles 5 is 0.5 μm.

<Example 17>
(Light wavelength conversion particle 6)
The light wavelength conversion particle 6 was obtained by the same procedure as the light wavelength conversion particle 1 except that the light wavelength conversion composition 11 was used instead of the light wavelength conversion composition 7. In the light wavelength conversion particles 6, red light emitting quantum dots were included in the binder particles, and the average particle diameter of the light wavelength conversion particles 6 was 0.5 μm.

<Comparative Example 7>
(Light wavelength conversion particle 7)
A light wavelength conversion particle 7 was obtained by the same procedure as that of the light wavelength conversion particle 1 except that the light wavelength conversion composition 15 was used instead of the light wavelength conversion composition 7. In the light wavelength conversion particles 7, green light emission quantum dots and red light emission quantum dots were included in the binder resin, and the average particle diameter of the light wavelength conversion particles 7 was 0.5 μm.

<Comparative Example 8>
(Light wavelength conversion particle 8)
A light wavelength conversion particle 8 was obtained by the same procedure as that of the light wavelength conversion particle 1 except that the light wavelength conversion composition 16 was used instead of the light wavelength conversion composition 7. In the light wavelength conversion particles 8, green light emitting quantum dots were encapsulated in the binder resin, and the average particle diameter of the light wavelength conversion particles 8 was 0.5 μm.

<Comparative Example 9>
(Light wavelength conversion particle 9)
Light wavelength conversion particles 9 were obtained by the same procedure as the light wavelength conversion particles 1 except that the light wavelength conversion composition 17 was used instead of the light wavelength conversion composition 7. In the light wavelength conversion particles 9, red light emitting quantum dots were encapsulated in the binder resin, and the average particle diameter of the light wavelength conversion particles 9 was 0.5 μm.

<< Preparation of composition containing light wavelength conversion particles >>
Each component was mix | blended so that it might become a composition shown below, and the light wavelength conversion particle containing composition was obtained.
<Example 18>
(Light wavelength conversion particle-containing composition 1)
-Light wavelength conversion particles 1: 20 parts by mass-Epoxy acrylate (product name "Unidic V-5500", manufactured by DIC): 80 parts by mass-Radical polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Irgacure ( Registered trademark) 184 ", manufactured by BASF Japan Ltd.): 1 part by mass

<Example 19>
(Light wavelength conversion particle-containing composition 2)
Light wavelength conversion particles 2: 20 parts by mass Epoxy acrylate (product name “Unidic V-5500”, manufactured by DIC): 80 parts by mass Radical polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name “Irgacure ( Registered trademark) 184 ", manufactured by BASF Japan Ltd.): 1 part by mass

<Example 20>
(Light wavelength conversion particle-containing composition 3)
Light wavelength conversion particle 3: 20 parts by mass Epoxy acrylate (product name “Unidic V-5500”, manufactured by DIC Corporation): 80 parts by mass Radical polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name “Irgacure ( Registered trademark) 184 ", manufactured by BASF Japan Ltd.): 1 part by mass

<Example 21>
(Light wavelength conversion particle-containing composition 4)
Light wavelength conversion particles 4: 20 parts by mass Epoxy acrylate (product name “Unidic V-5500”, manufactured by DIC): 80 parts by mass Radical polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name “Irgacure ( Registered trademark) 184 ", manufactured by BASF Japan Ltd.): 1 part by mass

<Example 22>
(Light wavelength conversion particle-containing composition 5)
Light wavelength conversion particles 1: 20 parts by mass Alicyclic epoxy resin (product name “Celoxide 2021P”, manufactured by Daicel Chemical Industries): 80 parts by mass Cationic polymerization initiator (product name “Sun-Aid SI-60L”, three Shin Chemical Co., Ltd.): 1 part by mass

<Example 23>
(Light wavelength conversion particle-containing composition 6)
-Light wavelength conversion particles 5: 4 parts by mass-Curable resin composition 1 (solid content 50%): 32 parts by mass-3-methoxybutyl acetate: 64 parts by mass

<Example 24>
(Light wavelength conversion particle-containing composition 7)
-Light wavelength conversion particles 6: 4 parts by mass-Curable resin composition 1 (solid content 50%): 32 parts by mass-3-methoxybutyl acetate: 64 parts by mass

<Comparative Example 10>
(Light wavelength conversion particle-containing composition 8)
Light wavelength conversion particles 7: 20 parts by mass Epoxy acrylate (product name “Unidic V-5500”, manufactured by DIC Corporation): 80 parts by mass Radical polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name “Irgacure ( Registered trademark) 184 ", manufactured by BASF Japan Ltd.): 1 part by mass

<Comparative Example 11>
(Light wavelength conversion particle-containing composition 9)
Light wavelength conversion particle 7: 20 parts by mass Alicyclic epoxy resin (product name “Celoxide 2021P”, manufactured by Daicel Chemical Industries): 80 parts by mass Cationic polymerization initiator (product name “Sun-Aid SI-60L”, three Shin Chemical Co., Ltd.): 1 part by mass

<Comparative Example 12>
(Light wavelength conversion particle-containing composition 10)
-Light wavelength conversion particles 8: 4 parts by mass-Curable resin composition 1 (solid content 50%): 32 parts by mass-3-methoxybutyl acetate: 64 parts by mass

<Comparative Example 13>
(Light wavelength conversion particle-containing composition 11)
-Light wavelength conversion particle 9: 4 parts by mass-Curable resin composition 1 (solid content 50%): 32 parts by mass-3-methoxybutyl acetate: 64 parts by mass

<Preparation of composition for overcoat layer>
Each component was mix | blended so that it might become a composition shown below, and the composition for overcoat layers was obtained.
(Composition 1 for overcoat layer)
-Zinc acrylate (product name "ZN-DA" manufactured by Nippon Shokubai Co., Ltd.): 25 parts by mass-Mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (product name "Aronix (registered trademark) M-403", Tojo (Manufactured by Kosei Co., Ltd.): 5 parts by mass, methanol: 70 parts by mass, photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name “Irgacure (registered trademark) 184, manufactured by BASF Japan): 1 part by mass

(Composition 2 for overcoat layer)
-Mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (product name "Aronix (registered trademark) M-403", manufactured by Toagosei Co., Ltd.): 30 parts by mass-Methanol: 70 parts by mass-Photopolymerization initiator (1 -Hydroxycyclohexyl phenyl ketone, product name “Irgacure (registered trademark) 184, manufactured by BASF Japan Ltd.”: 1 part by mass

<Preparation of composition for light diffusion layer>
Each component was mix | blended so that it might become a composition shown below, and the composition 1 for light diffusion layers was obtained.
(Composition 1 for light diffusion layer)
Pentaerythritol triacrylate: 99 parts by mass Light scattering particles (crosslinked polystyrene resin particles, product name “SBX-4”, manufactured by Sekisui Plastics Co., Ltd., average particle size 4 μm): 158 parts by mass Photoinitiator (1-hydroxycyclohexyl phenyl ketone, product name “Irgacure (registered trademark) 184, manufactured by BASF Japan Ltd.): 1 part by mass / solvent (methyl isobutyl ketone: cyclohexanone = 1: 1 (mass ratio)): 170 parts by mass

<Adjustment of composition for light shielding layer>
First, each component was mix | blended so that it might become the composition shown below, and the black pigment dispersion liquid 1 was obtained.
(Black pigment dispersion 1)
Black pigment: 23 parts by mass Polymer dispersion (product name “Disperbyk111”, manufactured by Big Chemie Japan): 2 parts by mass Diethylene glycol dimethyl ether: 75 parts by mass

Next, each component was mix | blended so that it might become a composition shown below, and the composition 1 for light shielding layers was obtained.
(Composition 1 for light shielding layer)
Black pigment dispersion 1: 61 parts by mass Curable resin composition 1: 20 parts by mass Diethylene glycol dimethyl ether: 30 parts by mass

<Example 25>
The composition for light diffusing layers is applied to one side of two polyethylene terephthalate (PET) substrates (product name “Lumirror T60”, manufactured by Toray Industries, Inc.) as light transmissive substrates having a size of 7 inches and a thickness of 50 μm. And coated to form a coating film. Next, the solvent in the coating film was evaporated by allowing the formed coating film to dry by passing dry air at 80 ° C. for 30 seconds. Then, the light diffusion layer having a film thickness of 10 μm was formed by irradiating ultraviolet rays so that the integrated light amount was 500 mJ / cm ² to cure the coating film, and a PET substrate with a light diffusion layer was formed.

  Subsequently, the light wavelength conversion composition 1 was apply | coated to the surface on the opposite side to the surface by the side of the light-diffusion layer in one PET base material with a light-diffusion layer, and the coating film was formed. And the other PET base material with a light-diffusion layer was laminated | stacked on the coating film so that the surface on the opposite side to the surface at the side of the light-diffusion layer in the other PET base material with a light-diffusion layer may contact | connect a coating film. In this state, the coating film is cured by heating at 100 ° C. to form a light wavelength conversion layer having a film thickness of 100 μm, and the light wavelength conversion layer and the two PET base materials with light diffusion layers are integrated. Turned into. As a result, an optical wavelength conversion sheet according to Example 25 was obtained.

<Examples 26 to 28 and Comparative Example 14>
In Examples 26 to 28 and Comparative Example 14, the light wavelength conversion was performed in the same manner as in Example 25 except that each light wavelength conversion composition shown in Table 2 was used instead of the light wavelength conversion composition 1. A sheet was produced.

<Examples 29 to 32 and Comparative Example 15>
In Examples 29 to 32 and Comparative Example 15, each light wavelength conversion particle-containing composition shown in Table 2 was used in place of the light wavelength conversion composition 1, and instead of heating at 100 ° C., the cumulative amount of ultraviolet light was increased. A light wavelength conversion sheet was produced in the same manner as in Example 25 except that the coating film of the light wavelength conversion-containing composition was cured by irradiation so as to be 500 mJ / cm ² .

<Example 33>
The optical wavelength conversion composition 1 was applied to one surface of a 50 μm thick polyethylene terephthalate (PET) substrate (product name “Lumirror T60”, manufactured by Toray Industries, Inc.) to form a coating film. And it heated at 100 degreeC, the coating film was hardened, and the light wavelength conversion layer was formed. And the composition 1 for overcoat layers was apply | coated to the surface on the opposite side to the surface by the side of the PET base material of a light wavelength conversion layer, and the coating film was formed. And the ultraviolet-ray was irradiated so that an integrated light quantity might be set to 500 mJ / cm < ² >, the coating film was hardened, and the overcoat layer with a film thickness of 5 micrometers was obtained. Subsequently, after peeling off the PET base material, the overcoat layer composition 1 was applied to the surface of the light wavelength conversion layer opposite to the surface on the overcoat layer side to form a coating film. And the ultraviolet-ray was irradiated so that an integrated light quantity might be set to 500 mJ / cm < ² >, the coating film was hardened, and the overcoat layer with a film thickness of 5 micrometers was obtained. This obtained the light wavelength conversion sheet which consists of a light wavelength conversion layer and the overcoat layer formed in both surfaces of the light wavelength conversion layer.

<Example 34>
In Example 34, a light wavelength conversion sheet was produced in the same manner as in Example 33 except that the overcoat layer composition 2 was used instead of the overcoat layer composition 1.

<Comparative Example 16>
In Comparative Example 16, a light wavelength conversion sheet was produced in the same manner as in Example 33 except that the light wavelength conversion composition 12 was used instead of the light wavelength conversion composition 1.

<Example 35 and Comparative Example 17>
In Example 35 and Comparative Example 17, each light wavelength conversion particle-containing composition shown in Table 2 was used instead of the light wavelength conversion composition 1, and instead of heating at 100 ° C., the integrated light amount was 500 mJ / A light wavelength conversion sheet was produced in the same manner as in Example 33 except that the coating film of the light wavelength conversion-containing composition was cured by irradiation so as to be cm ² .

<Example 36>
A prism layer composition containing urethane acrylate was uniformly applied to one surface of a polyethylene terephthalate (PET) base material (product name “Lumirror T60”, manufactured by Toray Industries, Inc.) having a thickness of 100 μm. A coating film was formed to form a prism sheet laminate. Then, the prism sheet laminate is traveled at a running speed so that the coating layer of the lens layer composition is on the molding die side and has a concave portion having a reverse shape with respect to the shape of the desired unit prism. The shape of the unit prism is formed on the coating film of the prism layer composition by a molding die by supplying at 20 m / min, and light such as ultraviolet rays is applied to the coating film of the prism layer composition through the PET substrate. Irradiation was performed to cure the coating film of the prism layer composition. Finally, the cured coating film of the prism layer composition was peeled off from the molding die together with the PET base material to obtain a prism sheet having a prism layer formed on one surface of the PET base material. The prism layer has a sheet-like main body, and is arranged side by side on the main body. Each prism layer extends in a direction intersecting the arrangement direction, has an apex angle of 90 °, a width of 47 μm, and a height. Had a plurality of triangular prism unit prisms.

  Subsequently, the light wavelength conversion composition 1 was applied to the surface of the prism sheet opposite to the surface on the prism layer side of the PET substrate to form a coating film. And the light wavelength conversion layer whose film thickness integrated with the prism sheet was 100 micrometers was formed by heating at 100 degreeC and hardening | curing a coating film. As a result, an optical wavelength conversion sheet according to Example 36 was obtained.

<Comparative Example 18>
In Comparative Example 18, a light wavelength conversion sheet was produced in the same manner as in Example 36 except that the light wavelength conversion composition 12 was used instead of the light wavelength conversion composition 1.

<Example 37 and Comparative Example 19>
In Example 37 and Comparative Example 19, each light wavelength conversion particle-containing composition shown in Table 2 was used instead of the light wavelength conversion composition 1, and instead of heating at 100 ° C., the integrated light amount was 500 mJ / A light wavelength conversion sheet was produced in the same manner as in Example 36 except that the coating film of the light wavelength conversion-containing composition was cured by irradiation so as to be cm ² .

<Example 38>
First, two barrier films were produced by the following method. Polyethylene terephthalate as a light-transmitting substrate having a size of 7 inches and a thickness of 50 μm is generated in a chamber by applying a high-frequency power with a frequency of 13.56 MHz and a power of 5 kW to an electrode in a high-frequency sputtering apparatus. A silica vapor deposition layer having a thickness of 50 nm and a refractive index of 1.46 made of a target material (silica) was formed on one side of a (PET) substrate (product name “Lumirror T60”, manufactured by Toray Industries, Inc.). Thus, two barrier films each having a silica vapor deposition layer formed on one surface of the PET substrate were formed.

Subsequently, the said composition 1 for light diffusion layers was apply | coated to the surface on the opposite side to the surface at the side of a silica vapor deposition layer in both barrier films, and the coating film was formed. Next, the solvent in the coating film was evaporated by allowing the formed coating film to dry by passing dry air at 80 ° C. for 30 seconds. Then, the light diffusion layer with a film thickness of 10 μm was formed by irradiating with ultraviolet rays so that the integrated light amount was 500 mJ / cm ² to cure the coating film, thereby forming a barrier film with a light diffusion layer.

  Subsequently, the light wavelength conversion composition 1 was apply | coated to the silica vapor deposition layer side of one barrier film with a light-diffusion layer, and the coating film was formed. And the other barrier film with a light-diffusion layer was laminated | stacked so that the silica vapor deposition layer might contact | connect the surface of the silica vapor deposition layer of the barrier film with a light-diffusion layer in a coating film. In this state, by heating at 100 ° C. to cure the coating film, a light wavelength conversion layer having a thickness of 100 μm adhered to both barrier films with a light diffusion layer was formed. As a result, an optical wavelength conversion sheet according to Example 38 was obtained.

<Comparative Example 20>
In Comparative Example 20, a light wavelength conversion sheet was produced in the same manner as in Example 38 except that the light wavelength conversion composition 12 was used instead of the light wavelength conversion composition 1.

<Example 39 and Comparative Example 21>
In Example 39 and Comparative Example 21, each light wavelength conversion particle-containing composition shown in Table 2 was used instead of the light wavelength conversion composition 1, and instead of heating at 100 ° C., the integrated light amount was 500 mJ / A light wavelength conversion sheet was produced in the same manner as in Example 38 except that the coating film of the light wavelength conversion-containing composition was cured by irradiation so as to be cm ² .

<Example 40>
The light wavelength conversion composition 1 was filled in the opening of a reflective member of a blue light emitting diode having an emission peak wavelength of 450 nm. And it heated at 100 degreeC, the filling was hardened, and the light source which concerns on Example 40 provided with the light wavelength conversion part with which the opening part of the reflective member of a blue light emitting diode was filled was obtained.

<Example 41 and Comparative Examples 22 and 23>
In Comparative Example 22, a light source was produced in the same manner as in Example 40 except that the light wavelength conversion composition or the light wavelength conversion particle-containing composition was used instead of the light wavelength conversion composition 1.

<Example 42>
The light wavelength conversion composition 1 was applied to a light incident surface of a light guide plate of a Kindle Fire (registered trademark) HDX7 backlight device described later to form a coating film. And it heated at 100 degreeC, the coating film was hardened, and the light wavelength conversion layer which concerns on Example 42 formed in the light-incidence surface of a light-guide plate was obtained.

<Comparative Example 24>
In Comparative Example 24, a light wavelength conversion layer was produced in the same manner as in Example 42 except that the light wavelength conversion composition 12 was used instead of the light wavelength conversion composition 1.

<Example 43 and Comparative Example 25>
In Example 43 and Comparative Example 25, each light wavelength conversion particle-containing composition shown in Table 2 was used instead of the light wavelength conversion composition 1, and instead of heating at 100 ° C., the integrated light amount was 500 mJ / A light wavelength conversion layer was produced in the same manner as in Example 42 except that the coating film of the light wavelength conversion-containing composition was cured by irradiation so as to be cm ² .

<Example 44>
First, the light shielding layer composition 1 was applied on a 0.7 mm thick glass substrate (product name “AN100” manufactured by Asahi Glass Co., Ltd.) with a spin coater, dried at 100 ° C. for 3 minutes, and a coating film having a thickness of about 1 μm. Formed. Then, this coating film is exposed to a predetermined shape with an ultra-high pressure mercury lamp, developed with 0.05 wt% potassium hydroxide aqueous solution, and then heat-treated by leaving the substrate in an atmosphere of 180 ° C. for 30 minutes. As a result, a light shielding layer patterned in a predetermined shape was formed.

  The light wavelength conversion composition 5 was applied by spin coating on the substrate on which the light shielding layer was formed, and then dried in an oven at 70 ° C. for 3 minutes. Next, a photomask is disposed at a distance of 100 μm from the coating film of the light wavelength conversion composition 5 and only a region corresponding to a region where a green pixel is to be formed using a 2.0 kW ultrahigh pressure mercury lamp by a proximity aligner. Ultraviolet rays were irradiated for 10 seconds. Subsequently, it was immersed in 0.05 mass% potassium hydroxide aqueous solution (liquid temperature 23 degreeC) for 1 minute, and alkali image development was carried out, and only the uncured part of this coating film was removed. Thereafter, the substrate was allowed to stand in an atmosphere of 180 ° C. for 30 minutes, so that a heat treatment was performed to form a green light wavelength conversion layer having a thickness of 2.0 μm in a region where a green pixel is to be formed.

  Next, using the light wavelength conversion composition 6, a red light wavelength conversion layer having a thickness of 2.0 μm was formed in a region where a red pixel was to be formed in the same process as the formation of the green light wavelength conversion layer. As a result, a color filter according to Example 44 was obtained.

<Example 45 and Comparative Examples 26 and 27>
In Example 45 and Comparative Examples 26 and 27, each of the light wavelength conversion compositions or the light wavelength conversion particle-containing compositions shown in Table 2 was used in place of the light wavelength conversion compositions 5 and 6, except that the light wavelength conversion composition was used. A color filter was produced in the same manner as in Example 44. The light wavelength conversion particle-containing compositions 6 and 10 and the light wavelength conversion composition 13 are used when forming the light wavelength conversion layer for green, and the light wavelength conversion particle-containing compositions 7 and 11 and the light wavelength conversion composition. The object 14 was used when forming the light wavelength conversion layer for red.

<Confirmation of elemental sulfur in light wavelength conversion particles>
In the light wavelength conversion particles 1 to 9 according to Examples 12 to 17 and Comparative Examples 7 to 9, it was confirmed whether or not elemental sulfur was detected from the binder resin. Specifically, using an energy dispersive X-ray analyzer (product name “JEM-2800” (100 mm ² silicon drift detector (SDD) installed, manufactured by JEOL Ltd.)), acceleration voltage 100 kV and measurement time 30 seconds. Under these conditions, it was confirmed whether or not sulfur element was detected at an arbitrary position on the surface or inside of the binder resin that was 3 nm or more away from the surface of the quantum dot shell. The confirmation criteria were as follows.
A: Elemental sulfur was detected.
X: Sulfur element was not detected.

<Measurement of sulfur element content in light wavelength conversion particles>
In the light wavelength conversion particles 1 to 9, the content of sulfur element contained in the light wavelength conversion particles was measured using a fluorescent X-ray analyzer (product name “EDX-800HS”, manufactured by Shimadzu Corporation).

<Measurement of sulfur element content in light wavelength conversion layer>
In the light wavelength conversion sheets according to Examples 25 to 39 and Comparative Examples 14 to 21, the content of the sulfur element contained in the light wavelength conversion layer was measured using an X-ray fluorescence analyzer (product name “EDX-800HS”, Shimadzu). (Manufactured by Seisakusho).

<Measurement of water vapor transmission rate and oxygen transmission rate>
In the light wavelength conversion sheets according to Examples 25 to 39 and Comparative Examples 14 to 21, the water vapor transmission rate and the oxygen transmission rate were measured, respectively. The water wavelength transmission sheet has a water vapor transmission rate of 40 ° C. and a relative humidity of 90% using a water vapor transmission rate measuring device (product name “PERMATRAN-W3 / 31”, manufactured by MOCON) in accordance with JIS K7129: 2008. The measurement was performed under the following conditions. In addition, the oxygen transmission rate of the light wavelength conversion sheet is 23 ° C. relative to an oxygen gas transmission rate measurement device (product name “OX-TRAN 2/21”, manufactured by MOCON) according to JIS K7126: 2006. Measurement was performed under the condition of 90% humidity.

<Measurement of luminance maintenance ratio after heat resistance test>
In the light wavelength conversion sheet, the light source, the light wavelength conversion layer, and the color filter according to the example and the comparative example, the light wavelength conversion sheet, the light source, the light wavelength conversion layer, and the color filter are left in an environment of 80 ° C. for 500 hours. A heat resistance test was performed, and the maintenance ratio of the luminance after the heat resistance test with respect to the luminance before the heat resistance test in the light wavelength conversion sheet, the light source, the light wavelength conversion layer, and the color filter was examined. Specifically, first, a backlight device of Kindle Fire (registered trademark) HDX7 was prepared, and a light wavelength conversion sheet before a heat resistance test was incorporated into the backlight device. This backlight device includes a blue light emitting diode having an emission peak wavelength of 450 nm, a light guide plate, a first prism sheet, and a second prism sheet in this order.

  In Examples 25-35, 38, and 39 and Comparative Examples 14-17, 20, and 21, the light guide plate is disposed so that the blue light emitting diode side is the light incident surface, and Example 25 is provided on the light exit surface of the light guide plate. To 35, 38 and 39 and Comparative Examples 14 to 17, 20, and 21 were disposed in this order to obtain a backlight device. Note that the second prism sheet was disposed so that the arrangement direction of the unit prisms was orthogonal to the arrangement direction of the unit prisms of the first prism sheet.

  In Examples 36 and 37 and Comparative Examples 18 and 19, the light guide plate is disposed so that the blue light-emitting diode side is the light incident surface, and the prism surface of the prism sheet is on the light output side of the light guide plate. Then, the light wavelength conversion sheet and the second prism sheet according to Examples 36 and 37 and Comparative Examples 18 and 19 were arranged in this order to obtain a backlight device. The second prism sheet was arranged so that the arrangement direction of the unit prisms was orthogonal to the arrangement direction of the unit prisms of the prism sheets in the light wavelength conversion sheets according to Examples 36 and 37 and Comparative Examples 18 and 19. In this way, backlight devices incorporating the light wavelength conversion sheets according to Examples 36 and 37 and Comparative Examples 18 and 19 were obtained.

  Then, the blue light emitting diode of the backlight device incorporating the light wavelength conversion sheet is turned on, the blue light is irradiated on one surface of the light wavelength conversion sheet, and the backlight device is passed through the other surface of the light wavelength conversion sheet. The luminance of light emitted from the light emitting surface (surface of the second prism sheet) is measured from the thickness direction of the light wavelength conversion sheet using a spectral radiance meter (product name “CS2000”, manufactured by Konica Minolta). The measurement was performed at an angle of 1 °.

  Subsequently, the light wavelength conversion sheet before the heat resistance test was removed from the backlight device, and a heat resistance test was performed on the light wavelength conversion sheet by leaving the light wavelength conversion sheet in an environment of 80 ° C. for 500 hours. And the light wavelength conversion sheet | seat after a heat resistance test was integrated in the said backlight apparatus similarly to the above. In this state, as described above, blue light is irradiated on one surface of the light wavelength conversion sheet, and the light emitting surface of the backlight device (the surface of the second prism sheet) is passed through the other surface of the light wavelength conversion sheet. ) Was measured from the thickness direction of the light wavelength conversion sheet using a spectral radiance meter (product name “CS2000”, manufactured by Konica Minolta) at a measurement angle of 1 °.

From these measured luminances, the maintenance ratio of the luminance after the heat resistance test with respect to the luminance before the heat resistance test was determined. The luminance maintenance factor is A, the luminance maintenance factor is A, the luminance of light emitted from the light emitting surface of the backlight device before the heat resistance test is B, and the luminance of light emitted from the light emitting surface of the backlight device after the heat resistance test. Was determined by the following formula.
A = C / B × 100

  Also in Examples 40 and 41 and Comparative Examples 22 and 23, the maintenance ratio of the luminance after the heat resistance test with respect to the luminance before the heat resistance test was determined in the same manner as described above. However, in Examples 40 and 41 and Comparative Examples 22 and 23, a heat resistance test was performed on the light source, and the blue light emitting diode was replaced with the light sources according to Examples 40 and 41 and Comparative Examples 22 and 23. A backlight device was used in which the light guide plate was disposed so that the side was the light incident surface, and the first prism sheet and the second prism sheet were disposed in this order on the light exit surface of the light guide plate.

  In Examples 42 and 43 and Comparative Examples 24 and 25, the luminance maintenance ratio after the heat resistance test with respect to the luminance before the heat resistance test was determined in the same manner as described above. However, in Examples 42 and 43 and Comparative Examples 24 and 25, the entire light guide plate is heat resistant to the light wavelength conversion layers according to Examples 42 and 43 and Comparative Examples 24 and 25 formed on the light incident surface of the light guide plate. The light guide plate was placed so that the blue light emitting diode side would be the light wavelength conversion layer, and the first prism sheet and the second prism sheet were placed in this order on the light exit surface of the light guide plate. A backlight device was used.

  In Examples 44 and 45 and Comparative Examples 26 and 27, the color filter was subjected to a heat resistance test under the same conditions as described above, and the color filter was disposed on the Kindle Fire (registered trademark) HDX7 backlight device. Then, the luminance maintenance rate after the heat resistance test with respect to the luminance before the heat resistance test in the color filter was determined by measuring the luminance of the light emitted from the color filter in the same manner as described above.

<Measurement of luminance retention after wet heat resistance test>
In the light wavelength conversion sheet, the light source, the light wavelength conversion layer, and the color filter according to the above examples and comparative examples, the light wavelength conversion sheet, the light source, the light wavelength conversion layer, and the color filter are in an environment of 60 ° C. and a relative humidity of 90%. A moisture and heat resistance test was conducted for 500 hours, and the luminance maintenance rate after the moisture and heat resistance test with respect to the luminance before the moisture and heat resistance test in the light wavelength conversion sheet, the light source, the light wavelength conversion layer, and the color filter was examined. Specifically, first, a backlight device of Kindle Fire (registered trademark) HDX7 is prepared, and the light wavelength conversion sheets before the moisture and heat resistance test according to Examples 25 to 39 and Comparative Examples 14 to 21 are used as the heat resistance test. Similarly, each was incorporated in this backlight device.

  Then, the blue light emitting diode of the backlight device incorporating the light wavelength conversion sheet is turned on, the blue light is irradiated on one surface of the light wavelength conversion sheet, and the backlight device is passed through the other surface of the light wavelength conversion sheet. The luminance of light emitted from the light emitting surface (surface of the second prism sheet) is measured from the thickness direction of the light wavelength conversion sheet using a spectral radiance meter (product name “CS2000”, manufactured by Konica Minolta). The measurement was performed at an angle of 1 °.

  Next, the light wavelength conversion sheet before the wet heat resistance test is removed from the backlight device, and a heat resistance test is performed on the light wavelength conversion sheet by leaving the light wavelength conversion sheet in an environment of 60 ° C. and 90% relative humidity for 500 hours. It was. And the light wavelength conversion sheet after the wet heat resistance test which concerns on Examples 25-39 and Comparative Examples 14-21 was each incorporated in the said backlight apparatus similarly to the above. In this state, as described above, blue light is irradiated on one surface of the light wavelength conversion sheet, and the light emitting surface of the backlight device (the surface of the second prism sheet) is passed through the other surface of the light wavelength conversion sheet. ) Was measured from the thickness direction of the light wavelength conversion sheet using a spectral radiance meter (product name “CS2000”, manufactured by Konica Minolta) at a measurement angle of 1 °.

From these measured luminances, the maintenance ratio of the luminance after the moist heat resistance test with respect to the luminance before the moist heat resistance test was determined. The luminance maintenance factor is D, the luminance maintenance factor is D, the luminance of light emitted from the light emitting surface of the backlight device before the moisture and heat resistance test is E, and the luminance of light emitted from the light emitting surface of the backlight device after the moisture and heat resistance test. Was determined by the following formula.
D = F / E × 100

  Also in Examples 40 and 41 and Comparative Examples 22 and 23, the maintenance ratio of the luminance after the moist heat resistance test with respect to the luminance before the moist heat resistance test was determined in the same manner as described above. However, in Examples 40 and 41 and Comparative Examples 22 and 23, a moisture and heat resistance test was performed on the light source, and the blue light emitting diode was replaced with the light sources according to Examples 40 and 41 and Comparative Examples 22 and 23. A backlight device was used in which the light guide plate was disposed so that the side was the light incident surface, and the first prism sheet and the second prism sheet were disposed in this order on the light exit surface of the light guide plate.

  Also in Examples 42 and 43 and Comparative Examples 24 and 25, the maintenance ratio of the luminance after the moist heat resistance test with respect to the luminance before the moist heat resistance test was determined in the same manner as described above. However, in Examples 42 and 43 and Comparative Examples 24 and 25, each light guide plate has moisture resistance with respect to the light wavelength conversion layers according to Examples 42 and 43 and Comparative Examples 24 and 25 formed on the light incident surface of the light guide plate. A thermal test was performed, and the light guide plate was arranged so that the blue light emitting diode side would be the light wavelength conversion layer, and the first prism sheet and the second prism sheet were arranged in this order on the light output surface of the light guide plate. A backlight device was used.

  In Examples 44 and 45 and Comparative Examples 26 and 27, the color filter was subjected to a moisture and heat resistance test under the same conditions as described above, and the color filter was disposed on the Kindle Fire (registered trademark) HDX7 backlight device. Thus, by measuring the luminance of the light emitted from the color filter in the same manner as described above, the maintenance ratio of the luminance after the heat resistance test with respect to the luminance before the wet heat resistance test in the color filter was obtained.

<Spot-like luminance defect evaluation>
Using the above-described backlight device incorporating the light wavelength conversion sheet after the heat resistance test according to Examples 25 to 39 and Comparative Examples 14 to 21, there is a point-like luminance defect on the light emitting surface at the time of light emission in the backlight device. The presence was visually observed and evaluated. Further, using the above backlight device incorporating the light wavelength conversion sheet after the moisture and heat resistance test according to Examples 25 to 39 and Comparative Examples 14 to 21, similarly, the light emitting surface at the time of light emission in the backlight device is pointed. The presence or absence of a luminance defect was visually observed and evaluated. The evaluation criteria were as follows.
○: No dot-like luminance defect was confirmed.
Δ: Several point-like luminance defects were confirmed.
X: Many point-like brightness | luminance defects were confirmed.

<Measurement of degradation width of peripheral edge of optical wavelength conversion sheet>
Using the above backlight device incorporating the light wavelength conversion sheet after the heat resistance test according to Examples 25 to 39 and Comparative Examples 14 to 21, the luminance distribution on the light emitting surface at the time of light emission in the backlight device is expressed as the light wavelength. It measured using the 2D color luminance meter (Product name "UA-200", Topcon Technohouse company make) from the thickness direction of the conversion sheet. Then, from the measured luminance distribution of the light emitting surface, the position of the light emitting surface where the luminance is 80% with respect to the luminance of the central portion of the light emitting surface (luminance 80% position) is obtained, and is closest to the luminance 80% position on the light emitting surface. The shortest distance from the edge to the 80% luminance position was determined. And this shortest distance was calculated | required about 20 places at random, and the average value of these 20 shortest distances was made into the degradation width of the peripheral part of a light wavelength conversion sheet. In addition, using the above backlight device incorporating the light wavelength conversion sheet after the moisture and heat resistance test according to Examples 25 to 39 and Comparative Examples 14 to 21, the luminance distribution of the light emitting surface was measured in the same manner, and light emission was performed. The position of the light emitting surface where the luminance is 80% of the luminance at the center of the surface (80% luminance position) is obtained, and the shortest distance from the edge closest to the 80% luminance position on the light emitting surface to the luminance 80% position is obtained. It was.

The results are shown in Tables 1 to 4 below.

  The results will be described below. As can be seen from Table 3 and Table 4, in the light wavelength conversion sheet according to Examples 25 to 37, a light wavelength conversion layer or a light wavelength conversion particle is formed using a light wavelength conversion composition containing an epoxy compound and a thiol compound. Therefore, compared to the light wavelength conversion sheets according to Comparative Examples 14 to 19 in which the light wavelength conversion particles and the light wavelength conversion particles are formed using the light wavelength conversion particles not containing the thiol compound, the heat resistance test is performed and the moisture resistance is increased. The luminance maintenance rate after the thermal test was high. Moreover, in the light wavelength conversion sheet | seat which concerns on Example 38, 39, since the light wavelength conversion layer and the light wavelength conversion particle are formed using the light wavelength conversion composition containing an epoxy compound and a thiol compound, a thiol compound is used. Compared to the light wavelength conversion sheets according to Comparative Examples 20 and 21 in which the light wavelength conversion layer and the light wavelength conversion particles are formed using the light wavelength conversion composition not included, the luminance maintenance ratio after the heat resistance test and after the heat and humidity resistance test Was high. Moreover, in the light source which concerns on Examples 40 and 41, since the light wavelength conversion layer and the light wavelength conversion particle are formed using the light wavelength conversion composition containing an epoxy compound and a thiol compound, the light which does not contain a thiol compound Compared with the light sources according to Comparative Examples 22 and 23 in which the light wavelength conversion layer and the light wavelength conversion particles were formed using the wavelength conversion composition, the luminance maintenance rate after the heat resistance test and after the wet heat resistance test was high. Moreover, in the light wavelength conversion layer which concerns on Example 42, 43, since the light wavelength conversion layer and the light wavelength conversion particle are formed using the light wavelength conversion composition containing an epoxy compound and a thiol compound, a thiol compound is used. Compared to the light wavelength conversion layers according to Comparative Examples 24 and 25 in which the light wavelength conversion layer and the light wavelength conversion particles are formed using the light wavelength conversion composition not included, the luminance maintenance rate after the heat resistance test and after the heat and humidity resistance test Was expensive. Furthermore, in the color filter which concerns on Example 44, 45, since the light wavelength conversion layer and the light wavelength conversion particle are formed using the light wavelength conversion composition containing an epoxy compound and a thiol compound, a thiol compound is not included. Compared with the color filters according to Comparative Examples 26 and 27 in which the light wavelength conversion layer and the light wavelength conversion particles were formed using the light wavelength conversion composition, the luminance maintenance rate after the heat resistance test and after the heat and humidity resistance test was high. This is because the cured products of the light wavelength conversion compositions 1 to 11 according to Examples 1 to 11 have high heat resistance and moist heat resistance, and sulfur components in the light wavelength conversion layer and the light wavelength conversion particles are deteriorated quantum dots. It can be suppressed.

  In the light wavelength conversion sheets according to Examples 25 to 37 and Comparative Examples 14 to 19, no barrier film was used, and thus no point-like luminance defect was confirmed. Moreover, in the light wavelength conversion sheet | seat which concerns on Example 38, 39, although the barrier film is used, a light wavelength conversion layer and a light wavelength conversion particle are formed using the light wavelength conversion composition containing an epoxy compound and a thiol compound. As a result, no dot-like luminance defect was confirmed. On the other hand, in the light wavelength conversion sheets according to Comparative Examples 20 and 21 in which the light wavelength conversion layer and the light wavelength conversion particles are formed using the light wavelength conversion composition that does not contain a thiol compound, dot-like luminance defects are confirmed. It was done. This means that the sulfur component in the light wavelength conversion layer or the light wavelength conversion particles can suppress the deterioration of the quantum dots.

  In the light wavelength conversion sheets according to Examples 25 to 39, since the light wavelength conversion layer and the light wavelength conversion particles are formed using the light wavelength conversion composition containing the epoxy compound and the thiol compound, the deterioration of the peripheral portion is It was suppressed. On the other hand, in the light wavelength conversion sheets according to Comparative Examples 14 to 19 in which the light wavelength conversion layer and the light wavelength conversion particles are formed using the light wavelength conversion composition that does not contain the thiol compound, the deterioration of the peripheral portion is confirmed. It was. This means that the sulfur component in the light wavelength conversion layer or the light wavelength conversion particles can suppress the deterioration of the quantum dots even in an environment where the quantum dots such as the peripheral part are exposed to a large amount of oxygen and water vapor. . Moreover, although the deterioration of the center part was comparatively suppressed by the barrier film, the optical wavelength conversion sheet | seat which concerns on Comparative Examples 20 and 21 was not suppressed deterioration of a peripheral part.

  The total haze value of the light wavelength conversion sheet according to Example 25 is 98.9%, the internal haze value is 96.7%, and the external haze value is 2.2%. The haze value was 99.3%, the internal haze value was 99.3%, and the external haze value was 0%. In both light wavelength conversion sheets, since the external haze value is smaller than the internal haze value, the brightness is high both before and after the heat resistance test and before and after the wet heat resistance test, but the light wavelength according to Example 25 When the conversion sheet and the light wavelength conversion sheet according to Example 26 were compared, the light wavelength conversion sheet according to Example 26 had higher luminance regardless of before and after the heat resistance test. This is because the light wavelength conversion sheet according to Example 26 contains alumina particles as light scattering particles, and therefore the internal haze value of the light wavelength conversion sheet according to Example 26 is the same as that of the wavelength conversion sheet according to Example 25. This is because it is larger than the internal haze value, thereby reducing the external haze value. Therefore, it was confirmed that by adding light scattering particles to the light wavelength conversion sheet and further increasing the internal haze value, the external haze value can be further reduced, thereby further improving the light wavelength conversion efficiency. . In addition, the total haze value, internal haze value, and haze value in the light wavelength conversion sheet were measured as follows. First, using a haze meter (product name “HM-150”, manufactured by Murakami Color Research Laboratory), all haze values of the light wavelength conversion sheet were measured according to JIS K7136. Thereafter, a triacetylcellulose base material (product name “Panaclean PD-S1”, manufactured by Panac Co., Ltd.) having a thickness of 25 μm is formed on both surfaces of the light wavelength conversion sheet via a transparent optical adhesive layer (product name “Panaclean PD-S1”, manufactured by Panac Corporation). TD60UL "(manufactured by FUJIFILM Corporation) was pasted. Thereby, the uneven shape of the surface in the light wavelength conversion sheet was crushed, and the surface of the light wavelength conversion sheet became flat. In this state, the haze value was measured according to JIS K7136 using a haze meter (product name “HM-150”, manufactured by Murakami Color Research Laboratory) to determine the internal haze value. And the external haze value was calculated | required by subtracting an internal haze value from all the haze values. Note that the transparent optical adhesive layer and the triacetylcellulose base material may also affect the internal haze value and external haze value of the light wavelength conversion sheet, but when the internal scattering of the light wavelength conversion sheet is extremely large, The influence on the internal haze value and external haze value is extremely small and can be ignored. Further, when the internal scattering of the light wavelength conversion sheet is extremely large, the internal haze value may be the same as the total haze value, so the external haze value may be 0%.

  Further, in the light wavelength conversion sheet according to Examples 33 and 34, a scratch test was performed on the overcoat layer, and the vertical force and horizontal force at that time were measured. As a result, the light wavelength conversion sheet according to Example 33 was The vertical force was 21 μN, the horizontal force was −11 μN, and the optical wavelength conversion sheet according to Example 34 had a vertical force of 11 μN and a horizontal force of −6 μN. These overcoat layers became dense films and had the ability to prevent the light wavelength conversion layer from being exposed to the atmosphere. However, the ability to prevent the light wavelength conversion layer from being exposed to the atmosphere was that of the light wavelength conversion sheet according to Example 33. It can be said that the overcoat layer is higher than the overcoat layer of the light wavelength conversion sheet according to Example 34. The scratch test was performed by using a nanoindentation device (product name “TI950 TriboIndenter”, manufactured by HYSITRON Co., Ltd.) from the cross section of the overcoat layer to the inside of the overcoat layer (Cube Corner: Ti037_110410 (12) ) Was pushed by 50 nm, the depth was kept constant, and this indenter was moved in the horizontal direction at a moving speed of 4 μm / min for 30 seconds. The vertical force (load) and horizontal force at that time were measured and measured. The average value of the vertical force and the horizontal force is obtained, and the average value of the five average values of the vertical force (5 times average value) obtained by repeating this scratch test five times is defined as the vertical force. The average value (average value of 5 times) of the average value was defined as the horizontal force.

  In the light wavelength conversion sheet which concerns on Examples 25-39, content of the sulfur element measured by the fluorescent X ray analysis was 0.5 mass% or more. On the other hand, in the light wavelength conversion sheet | seat which concerns on Comparative Examples 14-21, content of the sulfur element measured by the fluorescent X ray analysis was less than 0.5 mass%. In addition, in the light wavelength conversion sheets according to Comparative Examples 14 to 21, the content of the sulfur element is not 0% by mass even though the specific element is not included in the light wavelength conversion composition. This is probably because the quantum dot itself contained a sulfur component.

  In the above embodiment, CdSe is used as the core material of the green light emitting quantum dots and the red light emitting quantum dots. However, even when a non-Cd material such as InP or InAs is used as the core material, the same results as in the above embodiments are obtained. was gotten.

DESCRIPTION OF SYMBOLS 1 ... Light wavelength conversion particle 2 ... Quantum dot containing resin particle 3 ... Binder resin 4 ... Quantum dot 5 ... Coat layer 10, 20, 30, 40, 50, 60, 70 ... Light wavelength conversion sheet 11, 180, 201 ... Light Wavelength conversion layer 17 ... Light scattering particles 18 ... Coating films 80, 190 ... Image display devices 90, 140, 150, 170 ... Backlight device 130 ... Display panel 164 ... Light wavelength conversion unit 200 ... Color filter

Claims (17)

A light wavelength conversion composition comprising:
A light wavelength conversion composition comprising a quantum dot, a compound having a heterocyclic group containing an oxygen atom, and a thiol compound.   The light wavelength conversion composition according to claim 1, wherein the compound having a heterocyclic group has one or more heterocyclic groups, and the thiol compound has two or more thiol groups.   The light wavelength conversion composition according to claim 1, wherein the thiol compound is a primary thiol compound.   The light wavelength conversion composition of Claim 1 which further contains a hardening | curing agent.   The quantum dot includes a core made of a first semiconductor compound, a shell covering the core and made of a second semiconductor compound different from the first semiconductor compound, and a ligand bonded to the surface of the shell. The light wavelength conversion composition according to claim 1.   The light wavelength conversion composition according to claim 1, further comprising light scattering particles. Including quantum dots-containing resin particles including a binder resin and quantum dots encapsulated in the binder resin,
The light wavelength conversion particle | grains whose said quantum dot containing resin particle is the hardened | cured material of the light wavelength conversion composition of Claim 1.   The light wavelength conversion particles according to claim 7, wherein an average particle diameter of the light wavelength conversion particles is not less than twice the average particle diameter of the quantum dots and not more than 50 μm.   The light wavelength conversion particle according to claim 7, further comprising a coat layer covering a surface of the quantum dot-containing resin particle.   The light wavelength conversion member containing the hardened | cured material of the light wavelength conversion composition of Claim 1, or the light wavelength conversion particle of Claim 7. A light wavelength conversion sheet,
A light wavelength conversion sheet comprising a light wavelength conversion layer comprising a cured product of the light wavelength conversion composition according to claim 1 or a light wavelength conversion layer comprising the light wavelength conversion particles according to claim 7. Water vapor transmission rate at 40 ° C. and relative humidity 90% is 0.1 g / (m ² · 24 h) or more and oxygen transmission rate at 23 ° C. and relative humidity 90% is 0.1 cm ³ / (m ² · 24 h · atm The optical wavelength conversion sheet according to claim 11 satisfying at least one of the above.   The light wavelength conversion sheet according to claim 11, further comprising an overcoat layer made of a resin that covers at least one surface of the light wave conversion layer.   The optical wavelength conversion according to claim 11, further comprising an optical member on at least one surface side of the optical wavelength conversion layer, and the optical wavelength conversion layer and the optical member being integrated without an air layer. Sheet.   The light wavelength conversion sheet according to claim 11, further comprising a barrier film provided on at least one surface of the light wavelength conversion layer and protecting the quantum dots from moisture and oxygen. A light source;
A backlight device comprising: the light wavelength conversion member according to claim 10 or the light wavelength conversion sheet according to claim 11 that receives light from the light source.   An image display device comprising the light wavelength conversion member according to claim 10, the light wavelength conversion sheet according to claim 11, or the backlight device according to claim 16.

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