Wavelength conversion member, light-emitting device, and liquid crystal display device

Abstract

Provided is a wavelength conversion member comprising a wavelength conversion layer containing a cured product obtained by curing a curable composition containing at least a phosphor and a thiol compound. The wavelength conversion member has protective organic layers having two substrates that each have a protective organic layer in contact with the wavelength conversion layer. The protective organic layer is a layer containing a cured product obtained by curing a curable composition containing at least a (meth)acrylate. At least one of the protective organic layer of one of the two substrates and the protective organic layer of the other substrate satisfies condition (1). Condition (1): When the protective organic layers are detached from the wavelength conversion layer and TOF-SIMS in the depth direction on the protective organic layer side is measured, thiol is detected from the detachment surface on the protective organic layer side, and, when the thiol-derived fragment intensity of the detachment surface is defined as Is, the depth at which the thiol-derived fragment intensity first becomes Is×1 / 10 is 3 nm or more.

Description

Wavelength conversion member, light-emitting device, and liquid crystal display device

[0001] The present invention relates to a wavelength conversion member, a light-emitting device, and a liquid crystal display device.

[0002] Liquid crystal display devices (LCDs) are becoming increasingly popular as image display devices that consume little power and save space. A liquid crystal display device typically consists of at least a light-emitting device and liquid crystal cells.

[0003] In recent years, liquid crystal display devices equipped with wavelength conversion elements in the light-emitting device have attracted attention (see, for example, Patent Document 1).

[0004] WO2019 / 186734

[0005] In a light-emitting device equipped with a wavelength conversion element, when light from a light source enters the wavelength conversion element, the phosphor contained in the element is excited by the incident light and emits fluorescence. By using phosphors with different emission characteristics, it is possible to emit red, green, and blue emission lines from the wavelength conversion element as fluorescence emitted by the phosphor and / or as light emitted from the light source and passing through the wavelength conversion element. This makes it possible to realize white light.

[0006] Light-emitting devices typically incorporate wavelength conversion members that have been cut into the desired shape from a raw material. When delamination occurs near the cut end of the wavelength conversion member cut from the raw material, oxygen can easily enter the interface between the wavelength conversion layer and the adjacent layer, and as a result, it is presumed that more oxygen penetrates the wavelength conversion layer. In liquid crystal displays, it is thought that the light-emitting performance of the phosphor deteriorates when oxygen penetrates the wavelength conversion layer, so it is desirable to suppress delamination near the cut end in order to maintain the light-emitting performance of the phosphor.

[0007] In view of the above, one aspect of the present invention aims to provide a wavelength conversion member capable of suppressing peeling at the cut end surface.

[0008] One aspect of the present invention is as follows: [1] A wavelength conversion member having a wavelength conversion layer between two substrates, wherein the wavelength conversion layer is a layer containing a cured product obtained by curing a curable composition containing at least a phosphor and a thiol compound, each of the two substrates has a protective organic layer in contact with the wavelength conversion layer, the protective organic layer is a layer containing a cured product obtained by curing a curable composition containing at least (meth)acrylate, and at least one of the protective organic layers of one of the two substrates and the other satisfy the following condition (1); Condition (1): Separating the protective organic layer and the wavelength conversion layer, TOF-SIMS (Time-of-Flight Secondary Ion Mass) in the depth direction on the protective organic layer side When the Spectrometry is measured, thiols are detected from the peeled surface on the protective organic layer side, and the depth at which the thiol-derived fragment intensity first becomes Is × 1 / 10 (also simply referred to as "the depth at which Is × 1 / 10") is 3 nm or more, with Is being the thiol-derived fragment intensity on the peeled surface. [2] The wavelength conversion member according to [1], wherein both the protective organic layer on one of the two substrates and the protective organic layer on the other satisfy condition (1). [3] A wavelength conversion member according to [1] or [2], wherein at least one of the protective organic layers on one of the two substrates satisfies the following condition (1-1): Condition (1-1): When the protective organic layer and the wavelength conversion layer are peeled apart and TOF-SIMS in the depth direction on the protective organic layer side is measured, thiols are detected from the peeled surface on the protective organic layer side, and the depth at which the thiol-derived fragment intensity first becomes Is × 1 / 10, when the thiol-derived fragment intensity on the peeled surface is Is, is 5 nm or more. [4] A wavelength conversion member according to [3], wherein both the protective organic layer on one of the two substrates and the protective organic layer on the other satisfy condition (1-1). [5] A wavelength conversion member according to any one of [1] to [4], wherein the elastic modulus of at least one of the protective organic layers on one of the two substrates is 7.0 GPa or less.[6] The wavelength conversion member according to any one of [1] to [5], wherein the elastic modulus of both the protective organic layer on one of the two substrates and the protective organic layer on the other is 7.0 GPa or less. [7] The wavelength conversion member according to any one of [1] to [6], wherein the (meth)acrylate is a compound containing a cyclic aliphatic hydrocarbon group and an ethylenically unsaturated double bond. [8] The wavelength conversion member according to any one of [1] to [7], wherein the phosphor comprises quantum dots. [9] The wavelength conversion member according to [4], wherein the elastic modulus of both the protective organic layer on one of the two substrates and the protective organic layer on the other is 7.0 GPa or less, the (meth)acrylate is a compound containing a cyclic aliphatic hydrocarbon group and an ethylenically unsaturated double bond, and the phosphor comprises quantum dots.

[10] A light-emitting device comprising the wavelength conversion member according to any one of [1] to [9] and a light source.

[11] A liquid crystal display device comprising the light-emitting device according to

[10] and a liquid crystal cell.

[0009] According to one aspect of the present invention, a wavelength conversion member capable of suppressing peeling at the cut edge can be provided. Furthermore, according to one aspect of the present invention, a light-emitting device including the above-mentioned wavelength conversion member and a liquid crystal display device including the above-mentioned light-emitting device can be provided.

[0010] This is a cross-sectional view showing an example of a wavelength conversion member. This is a conceptual perspective view showing an example of a wavelength conversion member. This is a plan view of the wavelength conversion member in Figure 2. This is a cross-sectional view taken along line III-III in Figures 2 and 3. This is a cross-sectional view illustrating an example of the shape of the resin layer of the wavelength conversion member. This is a partially enlarged view of Figure 4. This is a plan view showing an example of the pattern of a quantum dot-containing region. This is a plan view showing another example of the pattern of a quantum dot-containing region. This is a conceptual diagram illustrating a method for identifying the contour of a quantum dot-containing region. This is a conceptual diagram illustrating an example of a method for manufacturing a wavelength conversion member. This is a diagram conceptually illustrating the configuration of an example of a backlight unit. This is a diagram conceptually illustrating the configuration of an example of a liquid crystal display device.

[0011] The following description may be based on representative embodiments of the present invention. However, the present invention is not limited to such embodiments. In the present invention and this specification, a numerical range represented by "~" means a range that includes the numbers written before and after "~" as the lower and upper limits.

[0012] [Wavelength Conversion Member] One aspect of the present invention relates to a wavelength conversion member having a wavelength conversion layer between two substrates, wherein the wavelength conversion layer is a layer containing a cured product obtained by curing a curable composition containing at least a phosphor and a thiol compound, the two substrates each have a protective organic layer in contact with the wavelength conversion layer, the protective organic layer is a layer containing a cured product obtained by curing a curable composition containing at least (meth)acrylate, and at least one of the protective organic layer on one of the two substrates and the protective organic layer on the other satisfies the following condition (1).

[0013] Condition (1): When the protective organic layer and the wavelength conversion layer are peeled off and TOF-SIMS in the depth direction on the protective organic layer side is measured, thiols are detected from the peeled surface on the protective organic layer side, and the depth at which the thiol-derived fragment intensity first becomes Is × 1 / 10 (the depth at which Is × 1 / 10 occurs), when the thiol-derived fragment intensity on the peeled surface is denoted as Is, is 3 nm or more.

[0014] In the present invention and this specification, "wavelength conversion layer" refers to a layer in which, when light is incident from a light source to a wavelength conversion member, the phosphor contained in this layer is excited by the incident light and emits fluorescence. The phosphor can be, for example, a quantum dot. Details regarding quantum dots will be described later.

[0015] In the present invention and this specification, "thiol compound" refers to a compound containing one or more thiol groups (-SH) in one molecule. Details of thiol compounds will be described later.

[0016] In the present invention and this specification, "(meth)acrylate" refers to a compound containing one or more (meth)acryloyl groups in one molecule. The term "(meth)acryloyl group" is used to indicate either or both an acryloyl group and a methacryloyl group. Furthermore, a (meth)acryloyl group may be contained in (meth)acrylate in the form of a (meth)acryloyloxy group. The term "(meth)acryloyloxy group" is used to indicate either or both an acryloyloxy group and a methacryloyloxy group. The functional number of "(meth)acrylate" refers to the number of (meth)acryloyl groups contained in one molecule of (meth)acrylate. With respect to (meth)acrylate, "monofunctional" means that the number of (meth)acryloyl groups contained in one molecule is one, and "polyfunctional" means that the number of (meth)acryloyl groups contained in one molecule is two or more.

[0017] In the wavelength conversion member described above, the wavelength conversion layer is a layer that is in contact with the protective organic layer contained in each of the two substrates. Here, "in contact" means that they are directly adjacent without any other layers in between. The protective organic layer is the organic layer located on the outermost surface of the substrate on the wavelength conversion layer side, and is therefore referred to as the "protective organic layer" in this invention and specification. In this invention and specification, the "organic layer" is a layer whose main component is an organic substance. The organic layer may be a layer in which the content of the organic substance is 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 99% by mass or more. Alternatively, it may be a layer composed solely of organic substances. Here, a layer composed solely of organic substances means a layer that contains only organic substances, excluding impurities that are inevitably mixed in during the manufacturing process. In the organic layer, only one type of organic substance may be contained, or two or more types may be contained.

[0018] <Condition (1)> In the above wavelength conversion member, the protective organic layer contained in each of the two substrates is a layer in contact with the wavelength conversion layer, and at least one of these two protective organic layers satisfies condition (1). "Condition (1)" means that when the protective organic layer and the wavelength conversion layer are peeled off and TOF-SIMS in the depth direction on the protective organic layer side is measured, thiols are detected from the peeled surface on the protective organic layer side, and the depth at which the thiol-derived fragment intensity first becomes Is × 1 / 10 (the depth at which it becomes Is × 1 / 10) is 3 nm or more, when the thiol-derived fragment intensity on the peeled surface is denoted as Is. The depth at which it becomes Is × 1 / 10 shall be determined, for example, by the following method.

[0019] (1) Cut out multiple test pieces from the wavelength conversion member to be measured. (2) Fix one of the two base materials of the cut test piece onto a glass plate using adhesive or the like. Place the tip of the blade of a cutter (blade angle 30°, e.g., NT Cutter manufactured by NT Corporation) at a 45° angle to the glass plate and make an oblique cut to a depth that penetrates the wavelength conversion member. (3) Apply adhesive tape (e.g., polyester adhesive tape No. 31B manufactured by Nitto Denko Corporation) to the surface of the cut in the test piece and peel off the tape repeatedly to obtain a peeled surface from which a portion of the wavelength conversion member has been removed. (4) Perform the above operations (1) to (3) on multiple test pieces to obtain multiple test pieces in which the peeled surface is exposed on the outermost surface. From the multiple test pieces, select the test piece in which the peeled surface, which has been peeled near the interface between the protective organic layer and the wavelength conversion layer, is exposed on the outermost surface. For example, a test piece that satisfies both of the following selection criteria (a) and (b) can be selected. The peeled surface exposed on the outermost surface of the selected test piece is called the "peeled surface on the protective organic layer side". (a) Observe the specimen with the delamination surface exposed on the outermost surface using a cross-sectional SEM (Scanning Electron Microscope). When comparing the thickness of the protective organic layer observed in the cross-sectional SEM image with the thickness of the protective organic layer formed for the fabrication of the wavelength conversion member, they are approximately the same thickness. Here, "approximately the same thickness" means a thickness of 95% to 105% when the thickness of the protective organic layer formed for the fabrication of the wavelength conversion member is taken as 100%. (b) In the TOF-SIMS measurement described below, fragments originating from the components of the protective organic layer are detected in the TOF-SIMS posi measurement or nega measurement at a depth of zero. (5) Perform a TOF-SIMS measurement on the delamination surface exposed on the outermost surface of the specimen selected above, i.e., the "delamination surface on the protective organic layer side", under the following conditions. As a measuring device, for example, the TRIFT V nanoTOF II manufactured by Ulvac PHI can be used. • Depth profiling: Combined with Ar (argon) ion sputtering • Measurement range: 256 points of raster scanning in one direction and its orthogonal direction • Polarity: posi, nega

[0020] The above "posi" and "nega" are abbreviations of "positive" and "negative" respectively. Whether or not thiol is detected from the peeling surface on the protective organic layer side is determined by whether or not HS ― fragment is detected in the nega measurement of TOF-SIMS at a depth of zero. HS, which is a fragment derived from thiol ― If the fragment is detected, it is determined that thiol is detected from the peeling surface on the protective organic layer side.

[0021] The TOF-SIMS measurement in the depth direction is performed as follows. The above HS ― The depth direction profile of the fragment is obtained by setting the sputtering conditions so that the resolution is 1 nm or less in the depth direction from the peeling surface on the protective organic layer side. The intensity of the HS ― fragment, the depth at which the intensity of the HS ― fragment first becomes Is×1 / 10 with respect to the intensity Is of the fragment at the peeling surface on the protective organic layer side is calculated. The depth (i.e., the distance from the peeling surface on the protective organic layer side) is calculated from the relationship between the sputtering time and the depth of erosion of the protective organic layer. The relationship between the sputtering time and the depth of erosion of the protective organic layer can be obtained by performing a preliminary experiment. Here, the "depth at which it first becomes Is×1 / 10" means that when the depth at which the intensity of the HS ― fragment becomes Is×1 / 10 appears at two or more locations as a result of the depth direction measurement, the depth of the shallowest location is taken as the "depth at which it first becomes Is×1 / 10". When the depth at which the intensity of the HS ― fragment becomes Is×1 / 10 appears at only one location, the depth of that location is taken as the "depth at which it first becomes Is×1 / 10". As described above, the "depth at which it first becomes Is×1 / 10" is also simply referred to as the "depth at which it becomes Is×1 / 10".

[0022] The deeper the depth to which the protective organic layer is Is × 1 / 10, the deeper the thiol compound, which is a component of the curable composition for forming the wavelength conversion layer that is in contact with the protective organic layer, can be said to have penetrated into the protective organic layer. Since the protective organic layer of the above wavelength conversion member is a layer containing a cured product obtained by curing a curable composition containing (meth)acrylate, the inventors believe that the thiol compound that has penetrated into the protective organic layer can contribute to improving the adhesion between the protective organic layer and the wavelength conversion layer by forming bonds with unreacted (meth)acrylate. Since a wider area where such bonds are formed can contribute to further improving the adhesion between the protective organic layer and the wavelength conversion layer, the inventors believe that a deeper depth to which Is × 1 / 10 is formed leads to suppression of peeling at the cut end surface of the wavelength conversion member. Therefore, from the viewpoint of suppressing peeling at the cut end surface of the wavelength conversion member, it is preferable that in the above wavelength conversion member, at least one of the protective organic layers of one of the two substrates and the other satisfy condition (1), and both satisfy condition (1). From the viewpoint of further suppressing peeling at the cut end surface of the wavelength conversion member, it is more preferable that at least one of the protective organic layers on one of the two substrates of the wavelength conversion member satisfies the following condition (1-1), and it is even more preferable that both satisfies the following condition (1-1). Condition (1-1): When the protective organic layer and the wavelength conversion layer are peeled off and TOF-SIMS in the depth direction on the protective organic layer side is measured, thiols are detected from the peeled surface on the protective organic layer side, and the depth at which the thiol-derived fragment intensity first becomes Is × 1 / 10, when the thiol-derived fragment intensity on the peeled surface is Is, is 5 nm or more.

[0023] In the protective organic layer of one of the two substrates and the protective organic layer of the other, the depth at which Is × 1 / 10 occurs can be, for example, 50 nm or less, 45 nm or less, 40 nm or less, 35 nm or less, or 30 nm or less. However, a deeper depth at which Is × 1 / 10 occurs is preferable from the viewpoint of suppressing peeling at the cut end surface of the wavelength conversion member, so the depth at which Is × 1 / 10 occurs may exceed the range exemplified herein.

[0024] Hereinafter, the wavelength conversion member will be described in more detail.

[0025] <Wavelength conversion layer> (phosphor) The phosphor contained in the wavelength conversion layer can be, for example, quantum dots.

[0026] The wavelength conversion layer may contain only one kind of quantum dots, or may contain two or more kinds of quantum dots having different light emission characteristics. Known quantum dots include quantum dots (A) having an emission center wavelength in a wavelength band ranging from 600 nm to 680 nm, quantum dots (B) having an emission center wavelength in a wavelength band ranging from 500 nm to less than 600 nm, and quantum dots (C) having an emission center wavelength in a wavelength band ranging from 400 nm to less than 500 nm. Quantum dots (A) can emit red light when excited by excitation light, quantum dots (B) can emit green light, and quantum dots (C) can emit blue light. For example, when blue light is incident as excitation light on a wavelength conversion member containing quantum dots (A) and quantum dots (B), white light can be realized by the red light emitted by quantum dots (A), the green light emitted by quantum dots (B), and the blue light that has passed through the wavelength conversion member. Also, by irradiating ultraviolet light as excitation light onto a wavelength conversion member containing quantum dots (A), (B), and (C), white light can be realized by the red light emitted by quantum dots (A), the green light emitted by quantum dots (B), and the blue light emitted by quantum dots (C).

[0027] In the present invention and this specification, light having an emission center wavelength in a wavelength band ranging from 400 nm to less than 500 nm is called blue light, light having an emission center wavelength in a wavelength band ranging from 500 nm to less than 600 nm is called green light, and light having an emission center wavelength in a wavelength band ranging from 600 nm to 680 nm is called red light. Also, the "full width at half maximum" of a peak means the width of the peak at half of the peak height.

[0028] Examples of quantum dots include core-shell type semiconductor nanoparticles. Generally, semiconductor particles with a particle size of 100 nm or less (e.g., several nm to tens of nm) can be called semiconductor nanoparticles. Examples of cores include II-VI group semiconductor nanoparticles, III-V group semiconductor nanoparticles, and multi-component semiconductor nanoparticles. Specifically, examples include CdSe, CdTe, CdS, ZnS, ZnSe, ZnTe, InP, InAs, and InGaP. However, it is not limited to these. CdSe, CdTe, InP, and InGaP are preferred because they can emit visible light with high efficiency. As shells, CdS, ZnS, ZnO, GaAs, and / or composites thereof can be used. However, it is not limited to these. Regarding quantum dots, prior art such as paragraphs 0060-0066 of Japanese Patent Publication No. 2012-169271 and paragraphs 0070-0076 of WO2018 / 186300 can be referenced. Commercially available quantum dots can be used, as can those manufactured by known methods. The luminescence properties of quantum dots can usually be adjusted by the composition and / or size of the particles.

[0029] In the above-mentioned wavelength conversion layer, the content of phosphors (e.g., quantum dots) can be in the range of, for example, 0.10 to 10.00% by mass relative to the mass of the wavelength conversion layer (i.e., with the mass of the wavelength conversion layer being 100.00% by mass). The phosphor content refers to the total content of two or more phosphors if they are included. This also applies to the content of various components in the present invention and this specification. Furthermore, the phosphor content in the curable composition for forming the wavelength conversion layer can be in the range of, for example, 0.10 to 10.00% by mass relative to the total amount of the composition. In the present invention and this specification, with respect to the curable composition, the content of each component relative to the total amount of the composition refers to the content calculated by assuming that the total content of all components excluding the solvent is 100.00% by mass if the curable composition contains a solvent. If the curable composition does not contain a solvent, the content of each component relative to the total amount of the composition refers to the content calculated by assuming that the total content of all components contained in the composition is 100.00% by mass.

[0030] The above wavelength conversion layer may be a layer containing a phosphor in a matrix, or a layer in which the phosphor is dispersed in the matrix. The matrix may contain a resin, and the resin may be a polymer of one or more polymerizable compounds. More specifically, the above wavelength conversion layer may be a layer containing a cured product obtained by curing a curable composition containing one or more phosphors, one or more polymerizable compounds, and one or more thiol compounds. In the present invention and this specification, "curable composition" is a composition containing at least one polymerizable compound, which has the property of curing when subjected to polymerization treatment such as light irradiation or heating. Also, "polymerizable compound" is a compound containing one or more polymerizable functional groups in one molecule. "Polymerizable functional group" is a group that can participate in polymerization reactions, for example, "(meth)acryloyl group" is a polymerizable functional group, and (meth)acrylate is a polymerizable compound.

[0031] (Thiol Compounds) The above curable composition contains at least a phosphor and a thiol compound. The thiol compound is one or more thiol compounds, and may be monofunctional or polyfunctional thiol. The number of functions in "thiol compound" refers to the number of thiol groups contained in one molecule of the thiol compound. For thiol compounds, "monofunctional" means that there is one thiol group contained in one molecule, and "polyfunctional" means that there are two or more thiol groups contained in one molecule. Polyfunctional thiol is a thiol with two or more functions, and preferably a thiol with three or more functions. For example, polyfunctional thiol can be a polyfunctional thiol with 8 or fewer functions, 7 or fewer functions, 6 or fewer functions, 5 or fewer functions, or 4 or fewer functions. From the viewpoint of improving the durability of the wavelength conversion member containing a cured product obtained by curing the above curable composition, the polyfunctional thiol is preferably one or more selected from the group consisting of difunctional to hexafunctional polyfunctional thiols, more preferably one or more selected from the group consisting of difunctional to tetrafunctional polyfunctional thiols, even more preferably one or more selected from the group consisting of trifunctional or tetrafunctional polyfunctional thiols, and even more preferably a trifunctional thiol.

[0032] Specific examples of polyfunctional thiols include ethylene bis(thioglycolate), diethylene glycol bis(3-mercaptopropionate), tetraethylene glycol bis(3-mercaptopropionate), 1,2-propylene glycol bis(3-mercaptopropionate), diethylene glycol bis(3-mercaptobutyrate), 1,4-butanediol bis(3-mercaptopropionate), 1,4-butanediol bis(3-mercaptobutyrate), and 1,4-bis(3-mercapto Thiryloxy)butane, 1,8-octanediol bis(3-mercaptopropionate), 1,8-octanediol bis(3-mercaptobutyrate), hexanediol bisthioglycolate, trimethylolpropantris(3-mercaptopropionate), trimethylolpropantris(3-mercaptobutyrate), trimethylolpropantris(3-mercaptoisobutyrate), trimethylolpropantris(2-mercaptoisobutyrate), trimethylolpropantris Thioglycolate, tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, trimethylolethanetris(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptoisobutyrate), pentaerythritol tetrakis(2-mercaptoisobutyrate), dipentaerythritol hexakis(3-mercaptopropyl Examples include thiol hexakis(2-mercaptopropionate), dipentaerythritol hexakis(3-mercaptobutyrate), dipentaerythritol hexakis(3-mercaptoisobutyrate), dipentaerythritol hexakis(2-mercaptoisobutyrate), pentaerythritol tetrakisthioglycolate, dipentaerythritol hexakisthioglycolate, and dipentaerythritol hexakis(3-mercaptopropionate). As for polyfunctional thiols, commercially available products can be used, and those synthesized by known methods can also be used.

[0033] The molecular weight of the polyfunctional thiol contained in the above curable composition can be, for example, 200 or more, and is preferably 300 or more from the viewpoint of further improving durability. Furthermore, from the viewpoint of improving brightness, the molecular weight of the polyfunctional thiol is preferably 1000 or less, and more preferably 500 or less.

[0034] In the present invention and this specification, molecular weight refers to the weight-average molecular weight for polymers (polymers include oligomers). Weight-average molecular weight refers to the weight-average molecular weight obtained by converting the measured value by gel permeation chromatography (GPC) to polystyrene equivalent. For example, the following conditions can be used for GPC measurement: GPC apparatus: HLC-8120 (manufactured by Tosoh Corporation) Column: TSK gel Multipore HXL-M (manufactured by Tosoh Corporation, 7.8 mm ID (Inner Diameter) × 30.0 cm)

[0035] In the above curable composition, the content of the thiol compound is preferably 5.00% by mass or more, more preferably 10.00% by mass or more, and even more preferably 15.00% by mass or more, relative to the total amount of the composition, from the viewpoint of improving the durability of the wavelength conversion member containing the cured product obtained by curing the above curable composition. Furthermore, from the viewpoint of further improving the above durability, the content of the thiol compound is preferably 40.00% by mass or less, more preferably 35.00% by mass or less, even more preferably 30.00% by mass or less, and even more preferably 25.00% by mass or less, relative to the total amount of the composition. The above curable composition may contain only one type of thiol compound or two or more types.

[0036] In one embodiment, the wavelength conversion layer may include a (meth)acrylic resin. In the present invention and this specification, "(meth)acrylic resin" means a polymer of (meth)acrylate. Polymers include homopolymers and copolymers.

[0037] The above wavelength conversion layer may be a layer containing a cured product obtained by curing a curable composition comprising one or more phosphors, one or more thiol compounds, and one or more (meth)acrylates. The various components that may be included in the above curable composition are described below.

[0038] ((meth)acrylate) The above curable composition may contain one or more (meth)acrylates selected from the group consisting of polyfunctional (meth)acrylates and monofunctional (meth)acrylates, and preferably contains at least one polyfunctional (meth)acrylate.

[0039] A polyfunctional (meth)acrylate is one or more types of (meth)acrylates with two or more functions, and can be one or more types selected from the group consisting of polyfunctional (meth)acrylates with two to eight functions, two to seven functions, two to six functions, two to five functions, or two to four functions.

[0040] Specific examples of difunctional (meth)acrylates include neopentyl glycol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, and the like.

[0041] Specific examples of (meth)acrylates with three or more functionalities include ECH (Epichloroxylin)-modified glycerol tri(meth)acrylate, EO (Ethylene Oxide)-modified glycerol tri(meth)acrylate, and PO (Propylene Examples include oxide-modified glycerol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, caprolactone-modified trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, tris(acryloxyethyl) isocyanurate, dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, and dipentaerythritol poly(meth)acrylate.

[0042] The molecular weight of the (meth)acrylate contained in the above curable composition can be, for example, 200 or more. From the viewpoint of the viscosity of the above curable composition, the molecular weight of the (meth)acrylate is preferably 1000 or less, and more preferably 500 or less.

[0043] In the above curable composition, the content of (meth)acrylate is preferably 10.00% by mass or more, more preferably 20.00% by mass or more, and even more preferably 30.00% by mass or more, based on the total amount of the composition, from the viewpoint of improving durability. Furthermore, in the above curable composition, the content of (meth)acrylate can be, for example, 90.00% by mass or less, or 80.00% by mass or less, based on the total amount of the composition. The above curable composition may contain only one type of polyfunctional (meth)acrylate, or it may contain two or more types.

[0044] (Functional group-containing compound) The above curable composition can contain a compound having a functional group selected from the group consisting of a carboxy group, a hydroxy group, a phosphoric acid group, and an amino group (also referred to as a "functional group-containing compound"). In the functional group-containing compound, the carboxy group may be contained in the form of -COOH or in the form of a salt. The salt of the carboxy group is a salt represented by -COO － M ＋ where M represents a cation such as an alkali metal ion. The phosphoric acid group is a monovalent functional group represented by -P=O(OH) ２ and may be contained in the form of -P=O(OH) ２ or in the form of a salt. The salt of the phosphoric acid group is a salt represented by -P=O(O － M ＋ ) ２ where M represents a cation such as an alkali metal ion. In the above, M ＋ represents a cation such as an alkali metal ion. The amino group may be any of a primary amino group, a secondary amino group, or a tertiary amino group. From the viewpoint of improving brightness, the above functional groups are preferably a carboxy group, a hydroxy group, and a phosphoric acid group, and more preferably a carboxy group.

[0045] Examples of the functional group-containing compound include various carboxylic acids such as saturated fatty acids such as acetic acid, propionic acid, and butyric acid, unsaturated fatty acids such as oleic acid and linoleic acid, aromatic carboxylic acids such as benzoic acid, and carboxylic acids having a plurality of carboxy groups such as oxalic acid and malonic acid.

[0046] Another example of the functional group-containing compound includes monofunctional or higher-functional (meth)acrylates having a functional group selected from the group consisting of a carboxy group, a hydroxy group, a phosphoric acid group, and an amino group. Hereinafter, such (meth)acrylate is also referred to as a "functional group-containing (meth)acrylate".

[0047] A functional group-containing (meth)acrylate has one or more functional groups selected from the group consisting of carboxyl groups, hydroxyl groups, phosphate groups, and amino groups in one molecule. The number of such functional groups can be 1 to 3 in one molecule, preferably 1 or 2, and more preferably 1. If a functional group-containing (meth)acrylate contains two or more of the above functional groups in one molecule, these two or more functional groups may be the same or different.

[0048] A functional group-containing (meth)acrylate is a monofunctional or multifunctional (meth)acrylate. From the viewpoint of improving brightness, monofunctional, difunctional, or trifunctional (meth)acrylates are preferred as functional group-containing (meth)acrylates, monofunctional or difunctional (meth)acrylates are more preferred, and monofunctional (meth)acrylates are even more preferred. A monofunctional (meth)acrylate can be represented, for example, by the formula: A-L-X. In the formula, A represents any of the above functional groups, L represents a divalent linking group, and X represents a (meth)acryloyl group or a (meth)acryloyloxy group. The divalent linking group represented by L can be, for example, one, two, or three or more combinations of divalent groups selected from the group consisting of alkylene groups, cycloalkylene groups, and ester groups (-O-C(=O)-). Examples of alkylene groups include linear or branched alkylene groups having 1 to 3 carbon atoms (e.g., methylene group, ethylene group, propylene group, etc.). Examples of cycloalkylene groups include cycloalkylene groups having 5 to 8 carbon atoms (e.g., cyclopentylene group, cyclohexylene group, cycloheptylene group, cyclooctylene group, etc.). The alkylene group may or may not have substituents, but an unsubstituted alkylene group is preferred. This also applies to cycloalkylene groups. An example of a monofunctional (meth)acrylate having a carboxyl group is acrylic acid. Acrylic acid is CH ２ =CHCOOH is a carboxylic acid, and the carbonyl group (-C(=O)-) is part of both the carboxyl group and the acryloyl group.

[0049] The molecular weight of the (meth)acrylate included as the functional group-containing (meth)acrylate can be, for example, 50 or more, and from the viewpoint of improving durability, it is preferably 70 or more, and more preferably 100 or more. Furthermore, from the viewpoint of improving brightness, the molecular weight of the (meth)acrylate included as the functional group-containing (meth)acrylate is preferably 500 or less, more preferably 400 or less, even more preferably 300 or less, and even more preferably 200 or less.

[0050] Specific examples of functional group-containing (meth)acrylates include carboxyl group-containing (meth)acrylates such as acrylic acid, β-carboxyethyl acrylate, 2-acryloyloxyethyl succinic acid, and 2-acryloyloxyethyl hexahydrophthalic acid; phosphate group-containing (meth)acrylates such as 2-acryloyloxyethyl acid phosphate; and hydroxyl group-containing (meth)acrylates such as 2-hydroxyethyl acrylate.

[0051] In the above curable composition, the content of the functional group-containing compound is preferably 0.50% by mass or more of the total amount of the composition from the viewpoint of improving brightness. Furthermore, the content of the functional group-containing compound is preferably 20.00% by mass or less of the total amount of the composition from the viewpoint of improving durability. The above curable composition may contain only one type of the functional group-containing compound, or it may contain two or more types. The content of the functional group-containing (meth)acrylate shall be included in the content of the functional group-containing compound.

[0052] (Additives) The above wavelength conversion layer and the above curable composition may optionally contain one or more additives. Specific examples of additives include polymerization initiators, acid-base generators, photobase generators, polymers, viscosity modifiers, silane coupling agents, surfactants, antioxidants, oxygen getters, polymerization inhibitors, inorganic particles, light scattering particles, white pigments, etc. Commercially available additives may be used, or additives prepared by known methods may be used. For details on specific examples of additives, etc., refer to paragraphs 0108 to 0169 of WO2018 / 186300, for example. Furthermore, the above curable composition does not have to contain a solvent, and may contain one or more solvents as needed. The type and amount of solvent are not limited. For example, one or more organic solvents may be used as the solvent.

[0053] (Thickness of the Wavelength Conversion Layer) The thickness of the above-mentioned wavelength conversion layer can be, for example, 100 μm or less, and from the viewpoint of thinning the wavelength conversion member, it is preferably 90 μm or less, more preferably 80 μm or less, even more preferably 70 μm or less, and even more preferably 60 μm or less. Furthermore, the thickness of the above-mentioned wavelength conversion layer can be, for example, 20 μm or more or 30 μm or more, and from the viewpoint of thinning the wavelength conversion member, it can also be lower than the values ​​exemplified herein.

[0054] In the present invention and this specification, the thickness of the wavelength conversion layer, substrate, support, etc. is determined by cutting the wavelength conversion member with a microtome, observing the cross-section of the section with a SEM, and measuring the thickness at a randomly selected location.

[0055] (Method for fabricating a wavelength conversion layer) In one form, the wavelength conversion layer can be a cured product obtained by curing a curable composition containing at least a phosphor and a thiol compound into a film. The term "film" shall be used synonymously with "sheet." A wavelength conversion layer of this form can be described as a continuous layer in which regions containing phosphors (more specifically, cured products obtained by curing a curable composition containing at least a phosphor and a thiol compound) are continuous. In contrast, in the wavelength conversion layer of the form described later, regions containing phosphors (more specifically, cured products obtained by curing a curable composition containing at least a phosphor and a thiol compound) exist as discontinuous layers.

[0056] For a method of manufacturing a wavelength conversion member having a wavelength conversion layer which is a cured product obtained by curing a curable composition containing at least a phosphor and a thiol compound into a film, see, for example, paragraphs 0127 to 0155, Figures 2 and 3 of WO2018 / 016589.

[0057] When curing is performed by light irradiation, the surface of the coating layer of the curable composition may be directly irradiated with light, or the surface of the substrate laminated on the coating layer may be irradiated with light. After laminating the substrate on the coating layer, the surface of the substrate may be irradiated with light after heat treatment. For example, after placing the coating layer between two substrates, the surface of the substrate may be irradiated with light after heat treatment. Performing heat treatment in this manner can contribute to increasing the depth to which Is × 1 / 10 is obtained. In one embodiment, from the viewpoint of ease of forming a thin wavelength conversion layer, the wavelength conversion layer can be formed as follows: A coating layer is formed by applying a curable composition to one of the two substrates used to manufacture the wavelength conversion member. When curing treatment (heating and / or light irradiation) is applied to this coating layer, the curing treatment is stopped when the polymerization reaction of the curable composition has partially progressed (hereinafter referred to as "partial curing"). After that, the other substrate is bonded to the partially cured coating layer, and then curing treatment is applied again to further advance the curing treatment.

[0058] Figure 1 is a cross-sectional view showing an example of a wavelength conversion member having a wavelength conversion layer which is a cured product obtained by curing a curable composition containing at least a phosphor and a thiol compound into a film. The wavelength conversion member 10 shown in Figure 1 has a wavelength conversion layer 3 between two substrates 1 and 2. The first substrate (substrate 1) and the second substrate (substrate 2) each have a support 4, an underlayment organic layer 5, an inorganic layer 6, and a protective organic layer 7. Details of the substrates will be described later.

[0059] In another embodiment, the wavelength conversion layer may have a phosphor-containing region (more specifically, a cured product obtained by curing a curable composition containing at least a phosphor and a thiol compound) and a resin layer region having a plurality of recesses, wherein the phosphor-containing region is included in the recesses. More specifically, the resin layer may have a plurality of discretely arranged recesses. Hereinafter, specific embodiments of such wavelength conversion layers will be described with reference to the drawings. However, the embodiments shown in the drawings are illustrative, and the present invention is not limited to the illustrated embodiments.

[0060] Figure 2 shows a perspective view of an example of a wavelength conversion member, Figure 3 shows a plan view of the wavelength conversion member shown in Figure 2, and Figure 4 shows a cross-sectional view taken along line III-III in Figures 2 and 3. The plan view of the wavelength conversion member is a view of the wavelength conversion member from a direction perpendicular to the main surface (maximum surface), and in this specification, unless otherwise noted, the plan view is a view of the wavelength conversion member from the second substrate side.

[0061] As shown in Figures 2 to 4, the wavelength conversion member 10 includes a first substrate 12, a second substrate 14, and a wavelength conversion layer 16. To clearly show the configuration of the wavelength conversion member 10, the second substrate 14 is shown with a dashed line in Figure 2, and the second substrate 14 is omitted in Figure 3. The support included in the substrate can be in the form of a film.

[0062] As shown in Figure 4, the first substrate 12, for example, has a support 12a and a barrier layer 12b. Similarly, the second substrate 14 also has a support 14a and a barrier layer 14b.

[0063] Furthermore, as shown in Figure 4, the wavelength conversion layer 16 includes a resin layer 18 (see Figure 5) having discrete recesses 18a formed in the planar direction (main planar direction) of the wavelength conversion member 10, and a cured product (phosphor-containing region) 20 formed by curing the curable composition in the recesses 18a of the resin layer 18. The phosphor-containing region 20 includes a phosphor 24 and a matrix 26 formed by a polymerization reaction of a polymerizable compound. That is, the wavelength conversion layer 16 has multiple phosphor-containing regions 20 containing the phosphor 24, spaced apart in the planar direction. More specifically, the phosphor-containing regions 20, which are regions containing the phosphor 24, are spaced apart from each other in the planar direction by walls forming the recesses 18a of the resin layer 18 and are arranged discretely in the planar direction.

[0064] In the present invention and this specification, "discretely arranged" more specifically means that, as shown in Figures 2 and 3, when observed from a direction perpendicular to the main surface of the first substrate 12 (plan view), the plurality of phosphor-containing regions 20 are arranged in isolation without contact with each other in the planar direction of the first substrate 12. In other words, the planar direction of the film is a two-dimensional direction along the film surface (main surface of the film). In the example shown in Figure 2, the phosphor-containing regions 20 are cylindrical and surrounded by the resin layer 18 in the planar direction of the first substrate 12.

[0065] In the wavelength conversion layer 16, the phosphor-containing regions 20 are discretely arranged in a two-dimensional direction. Therefore, assuming the wavelength conversion member 10 is part of a long film, even if the wavelength conversion member 10 is linearly cut at any point, as shown by the dashed line in Figure 3, the phosphor-containing regions 20 other than the cut portion are surrounded by the resin layer 18 and remain sealed in the planar direction. Furthermore, the phosphor-containing region 20 that is cut and exposed to the outside air may lose its function as a region containing the original phosphor 24. However, the phosphor-containing region 20 at the cut position, i.e., the phosphor-containing region 20 at the end in the planar direction, is usually covered by a frame or other component that constitutes a display device, and therefore does not need to function as a phosphor-containing region, thus not affecting the performance of the wavelength conversion member. Moreover, the deactivated phosphor can become a resin layer that protects the phosphor-containing regions not exposed to the outside air from the outside air.

[0066] In the wavelength conversion layer 16, the first substrate 12 is laminated on the main surface at the bottom of the recess 18a of the resin layer 18 of the wavelength conversion layer 16. That is, the first substrate 12 is laminated on the main surface on the closed side (closed end) of the recess 18a of the resin layer 18. In the illustrated example, the first substrate 12 is laminated with the barrier layer 12b facing the resin layer 18. On the other hand, the second substrate 14 is laminated on the main surface of the resin layer 18 constituting the wavelength conversion layer 16 that is opposite to the first substrate 12. That is, the second substrate 14 is laminated on the main surface on the open side (open end) of the recess 18a of the resin layer 18. In the illustrated example, the second substrate 14 is laminated with the barrier layer 14b facing the resin layer 18.

[0067] Depending on the method of forming the resin layer, the wavelength conversion layer may have through holes instead of recesses, with the substrate as the bottom surface, and the phosphor-containing region may be filled into the through holes. In this case, one of the two substrates sandwiching the resin layer, i.e., the wavelength conversion layer, is considered the first substrate and the other the second substrate film. Furthermore, the through holes are considered the recesses in the resin layer, and the first substrate is considered the bottom of the recesses in the resin layer. On the substrate side considered as the second substrate, the end of the wall portion of the resin layer 18 should be spaced apart from the second substrate, as will be described later.

[0068] Here, in the wavelength conversion layer 16, as shown in Figure 4, it is preferable that the end of the wall portion forming the recess 18a of the resin layer 18 on the second substrate 14 side is spaced apart from the second substrate 14. Furthermore, in the wavelength conversion member 10, it is preferable that a phosphor-containing region also exists between the end of the wall portion of the resin layer 18 that is spaced apart from the second substrate 14 on the second substrate 14 side and the second substrate 14. In a wavelength conversion member having a configuration in which a wavelength conversion layer, which is provided with a phosphor-containing region divided into multiple regions, is sealed with two substrates, the adhesion between the wavelength conversion layer and the substrate can be increased by providing a gap between the wall portion that divides the phosphor-containing region into multiple regions and the substrate, and by allowing phosphor to exist in this gap as well.

[0069] In the following explanation, the side of the wavelength conversion member 10 facing the second substrate 14, i.e., the opening side of the recess 18a of the resin layer 18, will be referred to as "upper," and the side facing the first substrate 12, i.e., the bottom side of the recess 18a of the resin layer 18, will be referred to as "lower."

[0070] Specifically, the wall portion that forms the recess 18a of the resin layer 18 is the portion between the recesses 18a of the resin layer 18 and the portion that forms the outer circumference of the resin layer 18 in the planar direction of the substrate. In other words, the wall portion that forms the recess 18a of the resin layer 18 is, in other words, the resin layer 18 in the planar direction of the wavelength conversion layer 16, the region between the phosphor-containing regions and the region outside the outermost phosphor-containing region in the planar direction.

[0071] Furthermore, in the examples shown in Figures 2 to 4, the phosphor-containing region (phosphor-containing region within the recess 18a) is cylindrical, and the wall portion forming the recess 18a of the resin layer 18 has a rectangular cross-sectional shape. However, the present invention is not limited thereto, and the cross-sectional shape of the wall portion can be of various shapes. For example, the wall portion forming the recess 18a of the resin layer 18 may have a trapezoidal cross-sectional shape, as conceptually shown on the left side of Figure 5, or it may have a cross-sectional shape in which the corners on the upper surface of the trapezoid are beveled into a curved shape, as conceptually shown on the right side of Figure 5. The cross-sectional shape of the wall portion of the resin layer 18 is preferably such that it gradually widens from the upper end downwards, at least in part, preferably from the upper end to the lower end, as shown in Figure 5. Here, "from the upper end downwards" means from the end on the second substrate 14 side toward the first substrate 12 side. Among these, the shape in which the corners on the upper surface of the second substrate side are beveled, as shown on the right side of Figure 5, is preferred. Such a shape is advantageous in terms of ease of manufacturing the mold for forming the resin layer 18, ease of removing the mold when forming the resin layer 18, and prevention of damage to the resin layer 18 being formed.

[0072] The wavelength conversion layer 16 has a wall portion that forms a recess 18a in the resin layer 18, with its upper end spaced apart from the second substrate 14. In addition to the recess 18a in the resin layer 18, the phosphor-containing region 20 is also provided between the upper end of the wall portion that is spaced apart from the second substrate 14 and the second substrate 14. In the illustrated example of the wavelength conversion member 10, as shown in Figure 4, all the wall portions have their upper ends spaced apart from the second substrate 14, and the phosphor-containing region 20 is provided between the wall portion and the second substrate 14. This configuration allows for good adhesion between the wavelength conversion layer 16 containing the phosphor 24 and the second substrate on the upper side, i.e., the opening side of the recess 18a in the resin layer 18.

[0073] As described later, in the manufacture of the wavelength conversion member, as an example, a mold having irregularities corresponding to the recesses and walls of the resin layer is filled with a coating liquid (resin layer forming composition) that will become the resin layer, a first substrate is laminated so as to cover the coating liquid filled in the mold, the coating liquid that will become the resin layer is cured, and the mold is removed to form a laminate of the first substrate and the resin layer. Next, a curable composition containing a phosphor is filled into the recesses of the resin layer, a second substrate is laminated on the resin layer so as to seal the curable composition filled in the resin layer, and then the curable composition is cured to produce a wavelength conversion member in which a wavelength conversion layer having a resin layer and a phosphor-containing region is sandwiched between the first substrate and the second substrate.

[0074] The first substrate and the resin layer can be laminated with sufficient adhesion because the resin layer is laminated in a liquid state and then the liquid is cured. Similarly, the resin layer and the phosphor-containing region can be laminated with sufficient adhesion because the curable composition is filled into the recesses and then cured. Here, regarding the wavelength conversion layer and the second substrate, the region corresponding to the recess of the resin layer where the curable composition containing the phosphor is filled is filled with the curable composition containing the phosphor in a liquid state and then cured, so good adhesion can be obtained. Furthermore, in the resin layer 18, at least a part of the wall portion constituting the recess 18a has its upper end separated from the second substrate 14, and the phosphor-containing region 20 exists not only in the recess 18a but also between the upper end of the wall portion separated from the second substrate 14 and the second substrate 14, thereby increasing the adhesion between the wavelength conversion layer 16 and the second substrate 14. In the present invention and this specification, the area between the upper end of the wall portion separated from the second base material 14 and the second base material 14 includes not only the area directly above the wall portion whose upper end is separated from the second base material 14, but also the area between the recess 18a (its upper end) adjacent in the planar direction to the wall portion whose upper end is separated from the second base material 14 and the second base material 14.

[0075] In the wavelength conversion layer 16, the wall portion of the resin layer 18 that is separated from the second substrate 14 is not limited to a configuration in which all upper ends of the wall portion are separated from the second substrate 14 and a phosphor-containing region is provided in between, as shown in Figure 4. The more wall portions of the resin layer 18 that are separated from the second substrate 14 there are, the higher the adhesion force between the wavelength conversion layer 16 and the second substrate 14 can be. Considering this point, in the wavelength conversion member 10, it is preferable that the upper ends of the wall portions corresponding to an area of ​​30% or more of the area of ​​the display portion of the display device in which the wavelength conversion member 10 is used are separated from the second substrate 14, and it is more preferable that the upper ends of all wall portions are separated from the second substrate 14 and the phosphor-containing region 20 and the second substrate 14 are in contact over the entire surface.

[0076] In the wavelength conversion layer 16, there are no particular restrictions on the gap g (shortest distance) between the upper end (uppermost part) of the wall portion that is separated from the second substrate 14; it is sufficient that they are separated (see Figure 6). Here, the gap g between the upper end of the wall portion and the second substrate 14 is preferably 0.01 to 10 μm, more preferably 0.05 to 4 μm, and even more preferably 0.1 to 4 μm. The gap g between the upper end of the wall portion and the second substrate 14 can be determined, for example, by cutting a portion of the wall portion of the wavelength conversion member 10 with a microtome or the like to form a cross-section, and observing the section with an SEM or the like. Note that "the portion of the wall portion of the wavelength conversion member 10" refers to "a portion of the wavelength conversion member 10 that is not the recess 18a." The gap g can be determined as the arithmetic mean of measurements taken at 10 randomly selected locations.

[0077] In the wavelength conversion layer 16, there are no particular restrictions on the depth h of the recess 18a of the resin layer 18, or the spacing t between adjacent phosphor-containing regions (between phosphor-containing regions within adjacent recesses 18a). The depth h of the recess in the resin layer 18 is preferably such that the thickness of the phosphor-containing region from the bottom of the recess 18a to the second substrate 14 (i.e., "depth h + gap g") is 1 to 100 μm. The spacing t between adjacent phosphor-containing regions is preferably 5 to 300 μm.

[0078] The thickness (also called height) of the phosphor-containing region is preferably 1 μm or more from the viewpoint of ease of achieving the target chromaticity. On the other hand, as the thickness of the phosphor-containing region increases, the amount of light absorbed in the phosphor-containing region increases. Considering these points, the thickness of the phosphor-containing region from the bottom of the recess 18a to the second substrate 14 is preferably 1 to 100 μm, more preferably 5 to 80 μm, and even more preferably 10 to 50 μm. The depth h of the recess 18a formed in the resin layer 18, and the thickness of the phosphor-containing region from the bottom of the recess 18a to the second substrate 14 can be determined by cutting the recess 18a portion of the wavelength conversion member with a microtome or the like to form a cross-section, irradiating the wavelength conversion layer 16 with excitation light to make the phosphor emit light, and observing this cross-section with a confocal laser microscope or the like. For the depth h and the thickness of the phosphor-containing region, the arithmetic mean of the measured values ​​of 10 randomly selected phosphor-containing regions can be used.

[0079] Furthermore, the distance t between adjacent phosphor-containing regions, that is, the thickness of the wall portion of the resin layer 18 between adjacent phosphor-containing regions (between adjacent recesses 18a), is preferably made short (the wall portion thin) in order to make the resin layer 18 invisible. On the other hand, from the viewpoint of strength and durability, the distance t between adjacent phosphor-containing regions is preferably above a certain value. From these viewpoints, the distance t between adjacent phosphor-containing regions is preferably 5 to 300 μm, more preferably 10 to 200 μm, and even more preferably 15 to 100 μm. The distance t between adjacent phosphor-containing regions is the shortest distance between adjacent phosphor-containing regions. This distance t can be determined by observing the surface from one side of the wavelength conversion member 10 using a confocal laser microscope or the like while the wavelength conversion layer 16 is irradiated with excitation light to cause the phosphor to emit light, and measuring the thickness of the wall portion of the resin layer 18 between adjacent phosphor-containing regions. Furthermore, the arithmetic mean of 20 randomly selected intervals can be used as the interval t between adjacent phosphor-containing regions.

[0080] The shape, size, and arrangement pattern of the phosphor-containing regions are not particularly limited and can be designed as appropriate. In the design, geometric constraints for arranging the phosphor-containing regions spaced apart from each other in a plan view, and tolerances for the width of the non-emitting regions that occur during cutting can be considered. Furthermore, for example, when using a printing method as one of the methods for forming the phosphor-containing regions, as will be described later, it is preferable that the occupied area of ​​each region be of a certain size or larger from the viewpoint of ease of printing. In this case, the occupied area refers to the occupied area in a plan view. Moreover, it is preferable from the viewpoint of improving the mechanical strength of the wavelength conversion member that the shortest distance between adjacent phosphor-containing regions, i.e., the thickness of the wall, is thick. The shape, size, and arrangement pattern of the phosphor-containing regions should be designed taking these points into consideration.

[0081] The ratio between the volume Vp of the phosphor-containing region and the volume Vb of the resin layer 18 can be any ratio. In one embodiment, the ratio "Vp / (Vp+Vb)" is preferably 0.1 ≤ Vp / (Vp+Vb) < 0.9, more preferably 0.2 ≤ Vp / (Vp+Vb) < 0.85, and even more preferably 0.3 ≤ Vp / (Vp+Vb) < 0.8. Here, the volume Vp of the phosphor-containing region and the volume Vb of the resin layer 18 are defined as the product of their respective areas and thicknesses when observed from a direction perpendicular to the main surface of the wavelength conversion member 10.

[0082] The wavelength conversion member 10 may have a configuration in which a wavelength conversion layer 16 having such a resin layer 18 and phosphor-containing region 20 is sandwiched between a first substrate 12 and a second substrate 14.

[0083] In the wavelength conversion member 10 shown in Figures 2 to 4, the phosphor-containing region (recess 18a) is cylindrical and circular in plan view. However, there are no particular restrictions on the shape of the phosphor-containing region. For example, as shown in Figure 7, the phosphor-containing region may be a polygonal prism or a regular polygonal prism, such as a square in plan view, or a hexagon (honeycomb structure) in plan view, as shown in Figure 8. In the above example, the base of the cylinder or polygonal prism is arranged parallel to the substrate surface. However, the base does not necessarily have to be arranged parallel to the substrate surface. Also, the shape of each phosphor-containing region may be irregular.

[0084] If the boundary between the matrix 26 of the phosphor-containing region and the resin layer 18 is not clear, as shown in Figure 9, the line connecting the points outside the phosphor 24e located in the outermost region where the phosphors 24 are placed (the side where the phosphors 24 are not placed) is considered as the contour m of the phosphor-containing region (the boundary between the phosphor-containing region and the resin layer 18). By irradiating the wavelength conversion layer with excitation light to cause the phosphors to emit light and observing them with, for example, a confocal laser microscope, the position of the phosphors can be identified, thereby identifying the contour m of the phosphor-containing region. In the present invention and this specification, meandering edges of cylinders and polygonal prisms, as shown in the contour in Figure 9, are also acceptable. Furthermore, in the above embodiment, the phosphor-containing regions are arranged in a periodic pattern. However, if the multiple phosphor-containing regions are arranged discretely, they may be aperiodic as long as the desired performance is not impaired. It is preferable that the phosphor-containing regions are uniformly distributed throughout the entire wavelength conversion layer 16, as this results in a uniform in-plane distribution of brightness.

[0085] To ensure sufficient fluorescence, it is preferable that the area occupied by the phosphor-containing region is large. The phosphor 24 in the phosphor-containing region may be one type or multiple types. Furthermore, even if one phosphor 24 in one phosphor-containing region is one type, among multiple phosphor-containing regions, the region containing the first phosphor and the region containing a second phosphor different from the first phosphor may be arranged periodically or aperiodically. There may be three or more types of phosphors. Details regarding the phosphors are as described above.

[0086] As mentioned earlier, there are no particular restrictions on the shape or arrangement pattern of the phosphor-containing region in the wavelength conversion layer. In all cases, because the phosphors are discretely arranged on the film surface, the phosphors in the phosphor-containing region at the cut edges may degrade. However, since the phosphors in parts other than the cut edges are surrounded and sealed by resin in the direction along the film surface, degradation of performance due to oxygen intrusion from the direction along the film surface can be suppressed.

[0087] As previously described, the wavelength conversion member 10 shown in Figures 2 to 4 has a configuration in which a wavelength conversion layer 16 is laminated on one surface of a first substrate 12, and a second substrate 14 is laminated on top of the wavelength conversion layer 16, so that the wavelength conversion layer 16 is sandwiched between the two substrates.

[0088] The resin layer 18 can be formed, for example, by preparing a resin layer-forming composition containing one or more polymerizable compounds, applying it, and curing it.

[0089] The shortest distance between phosphor-containing regions, i.e., the distance t between desirable phosphor-containing regions (recesses 18a), varies depending on the composition of the resin layer 18. The shortest distance between adjacent phosphor-containing regions of the resin layer 18 refers to the shortest distance within the film surface between adjacent phosphor-containing regions when observed from the main surface of the wavelength conversion member.

[0090] For resin layer-forming compositions (curable compositions), refer to paragraphs 0174-0179 of WO2018 / 186300. In one embodiment, the resin layer-forming composition may also contain a thiol compound. For details of the thiol compounds that may be included in the resin layer-forming composition and their content, refer to the prior description of thiol compounds included in curable compositions.

[0091] An example of the manufacturing process for wavelength conversion components will be explained with reference to the conceptual diagram in Figure 10.

[0092] First, a resin layer forming composition L1 for forming the resin layer 18 is prepared by adding a polymerizable compound to various components such as polymerization initiators, inorganic particles, and light scattering particles as needed. A curable composition containing at least a phosphor and a thiol compound is also prepared. Furthermore, a mold M having an uneven pattern corresponding to the recesses 18a and walls of the resin layer 18, as well as a first substrate 12 and a second substrate 14, are prepared for forming the resin layer 18.

[0093] After preparing these, first, as shown in the first and second steps of Figure 10, the prepared resin layer-forming composition L1 is filled into the prepared mold M, and as shown in the third step of Figure 10, the first substrate 12 is laminated onto the mold M so as to cover the entire surface of the resin layer-forming composition L1. Next, the resin layer-forming composition L1 is cured by, for example, ultraviolet irradiation to form a resin layer 18, and as shown in the fourth step of Figure 10, the mold M is removed from the resin layer 18. This forms a laminate in which a resin layer 18 is laminated on one surface of the first substrate 12 with the bottom of the recess 18a facing the first substrate 12.

[0094] In the wavelength conversion layer, the method for forming the recesses 18a of the resin layer 18 is not limited to the method shown in Figure 10, and various known methods for forming sheet-like materials with irregularities can be used. For example, examples include a method in which a resin layer forming composition L1 is first applied to a first substrate 12, a mold M is pressed onto the resin layer forming composition L1, and then the resin layer forming composition L1 is cured; a method in which the first substrate 12 and the mold M are laminated, the resin layer forming composition L1 is filled between the first substrate 12 and the mold M, and then the resin layer forming composition L1 is cured. In addition to these methods, methods such as forming a planar resin layer and then etching to form a resin layer 18 having recesses 18a, and using printing methods such as inkjet and dispenser methods to form a resin layer 18 having recesses 18a can also be used.

[0095] <Substrates> The above wavelength conversion member has the above wavelength conversion layer between two substrates. Each of these two substrates includes a protective organic layer in contact with the wavelength conversion layer. In one embodiment, the substrate may be a single-layer structure consisting of only one protective organic layer. In another embodiment, the substrate may be a laminated structure in which the protective organic layer and one or more other layers are laminated together. Of the two substrates of the above wavelength conversion member, only one may include a barrier layer, both may include a barrier layer, and it is preferable that both include a barrier layer. In the present invention and this specification, the "barrier layer" includes at least a protective organic layer and an inorganic layer, and may optionally include an underlying organic layer. In the wavelength conversion member, the barrier layer can function as a protective layer that mainly exhibits barrier properties to suppress the penetration of oxygen and / or water into the wavelength conversion layer. The two substrates of the above wavelength conversion member may be the same substrate, or they may be substrates with different layer configurations and / or constituent components. A substrate having a barrier layer includes at least a barrier layer, and from the viewpoint of durability of the substrate, it is preferable to include a support. The preferred layering order is "support / inorganic layer / protective organic layer / wavelength conversion layer". Here, " / " is used to encompass both the direct contact between the part described on the left and the part described on the right, and the presence of one or more other layers between them. However, in the above wavelength conversion member, the protective organic layer and the wavelength conversion layer are in contact without any other layers in between. That is, the protective organic layer and the wavelength conversion layer are in direct contact. For example, the support and the inorganic layer may be in direct contact, or one or more other layers (e.g., an underlayment organic layer) may be present between the support and the inorganic layer.

[0096] (Inorganic Layer) In the present invention and this specification, "inorganic layer" means a layer mainly composed of inorganic substances. The main component is the component that makes up the largest amount by mass among the components constituting the layer. The inorganic layer may be a layer in which the inorganic substance content is 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 99% by mass or more. Alternatively, it may be a layer composed solely of inorganic substances. Here, a layer composed solely of inorganic substances means a layer that contains only inorganic substances, excluding impurities that are inevitably mixed in during the manufacturing process. In the inorganic layer, only one type of inorganic substance may be contained, or two or more types may be contained.

[0097] Examples of inorganic materials constituting the inorganic layer include metals, or various inorganic compounds such as inorganic oxides, nitrides, and oxidized nitrides. Preferred elements constituting the inorganic material are silicon, aluminum, magnesium, titanium, tin, indium, and cerium, and these may be included one or more of each. Specific examples of inorganic materials include silicon oxide, aluminum oxide, magnesium oxide, titanium oxide, tin oxide, indium oxide alloy, silicon oxidized nitride, silicon nitride, aluminum nitride, and titanium nitride. In addition, a metal film, such as an aluminum film, silver film, tin film, chromium film, nickel film, or titanium film, may be provided as the inorganic layer.

[0098] Among the inorganic substances listed above, silicon nitrides, silicon oxides, and aluminum oxides are preferred. Regarding oxides, it is not relevant whether they have a stoichiometric or non-stoichiometric composition. The same applies to nitrides.

[0099] The method for forming the inorganic layer is not particularly limited, and various film-forming methods can be used, such as evaporating and / or scattering a film-forming material and depositing it on the surface on which the inorganic layer is to be formed. Examples include vacuum deposition, in which an inorganic material is heated and deposited; oxidation reaction deposition, in which an inorganic material is used as a raw material and deposited by oxidation by introducing oxygen gas; sputtering, in which an inorganic material is used as a target raw material and deposited by sputtering with argon gas and / or oxygen gas; chemical vapor deposition; and physical vapor deposition methods such as ion plating, in which an inorganic material is heated and deposited by a plasma beam generated by a plasma gun.

[0100] Inorganic layer thickness From the viewpoint of barrier properties, the thickness of the inorganic layer is preferably 30 nm or more, and more preferably 50 nm or more. Furthermore, from the viewpoint of thinning the wavelength conversion member, the thickness of the inorganic layer is preferably 600 nm or less, more preferably 500 nm or less, even more preferably 400 nm or less, even more preferably 300 nm or less, even more preferably 200 nm or less, and even more preferably 100 nm or less.

[0101] (Support) As the support for the substrate, a flexible, strip-shaped support that is transparent to visible light is preferred. Here, transparency to visible light means that the light transmittance in the visible light region is 80% or more, preferably 85% or more. The light transmittance used as a measure of transparency can be calculated by measuring the total light transmittance and scattered light amount using the method described in JIS K 7105:2008, i.e., an integrating sphere type light transmittance measuring device, and subtracting the diffuse transmittance from the total light transmittance. For flexible supports, refer to paragraphs 0046 to 0052 of Japanese Patent Publication No. 2007-290369 and paragraphs 0040 to 0055 of Japanese Patent Publication No. 2005-096108.

[0102] Specific examples of support materials include polyester films such as polyethylene terephthalate (PET), films made of polymers having a cyclic olefin structure, and polystyrene films.

[0103] Support Thickness The thickness of the support is preferably in the range of 6 to 75 μm, and more preferably in the range of 9 to 50 μm, from the viewpoint of improving the impact resistance of the wavelength conversion member.

[0104] (Protective organic layer, underlay organic layer) The two substrates of the above-mentioned wavelength conversion member each have at least a protective organic layer in contact with the wavelength conversion layer. For example, in the example wavelength conversion member 10 shown in Figure 1, the first substrate 1 and the second substrate 2 each have an underlay organic layer 5 between the support 4 and the inorganic layer 6, and a protective organic layer 7 between the inorganic layer 6 and the wavelength conversion layer 3. Either or both of the protective organic layer 7 of the first substrate 1 and the protective organic layer 7 of the second substrate 2 are protective organic layers that satisfy the condition (1) described above. Furthermore, in the example wavelength conversion member 10 shown in Figure 4, the barrier layer 12b of the first substrate (and the barrier layer 14b of the second substrate 14) has a structure in which three layers are laminated, as shown in the partially enlarged view A of Figure 4: an underlay organic layer 34 formed on the surface of the support 12a (support 14a), an inorganic layer 36 formed on the underlay organic layer 34, and a protective organic layer 38 formed on the inorganic layer 36. The protective organic layer 38 in contact with the phosphor-containing region 20 of the wavelength conversion layer 16 in the barrier layer 14b of the second substrate 14 is a protective organic layer that satisfies the previously described condition (1). As previously described, in one embodiment, the curable composition used as the resin layer forming composition may also contain a thiol compound. That is, the resin layer of the wavelength conversion layer may be a cured product obtained by curing a curable composition containing a thiol compound. In this case, the protective organic layer in contact with the resin layer may be a protective organic layer that satisfies the previously described condition (1). For example, in the example wavelength conversion member 10 shown in Figure 4, the protective organic layer 38 in contact with the resin layer 18 of the wavelength conversion layer 16 in the barrier layer 12b of the first substrate 12 may be a protective organic layer that satisfies the previously described condition (1).

[0105] The surface of the support 12a, that is, the underlying organic layer 34 beneath the inorganic layer 36, is a base layer (in other words, an undercoat layer) that can contribute to the proper formation of the inorganic layer 36. This is also true for the underlying organic layer 5 in the example shown in Figure 1.

[0106] The protective organic layer, for example, in the example shown in Figure 4, is a protective organic layer 38 formed on the surface of the inorganic layer 36, and is a protective layer (in other words, an overcoat layer) that can contribute to protecting the inorganic layer 36, which mainly exhibits barrier properties. It can also be a layer that enhances the adhesion between the inorganic layer and the wavelength conversion layer. The same applies to the protective organic layer 7 in the example shown in Figure 1.

[0107] The protective organic layer on each of the two substrates of the wavelength conversion member is a layer containing a cured product obtained by curing a curable composition containing at least (meth)acrylate. The protective organic layer can be, for example, a continuous layer in which the cured product is continuous.

[0108] For example, when curing a curable composition for forming a protective organic layer by light irradiation, the depth to which Is × 1 / 10 is obtained tends to increase as the amount of light irradiation decreases.

[0109] Specific examples of (meth)acrylates included in curable compositions for forming protective organic layers include, for example, the (meth)acrylates described earlier in relation to the wavelength conversion layer.

[0110] As for the (meth)acrylate included in the curable composition for forming the protective organic layer, from the viewpoint of increasing the depth to which Is × 1 / 10 is greater, and / or from the viewpoint of further enhancing the barrier properties that suppress the penetration of at least one of oxygen and water into the wavelength conversion layer in the wavelength conversion member, compounds containing a cyclic aliphatic hydrocarbon group and an ethylenically unsaturated double bond are preferred. "Ethylenelycol unsaturated double bond" refers to a carbon-carbon double bond.

[0111] From the viewpoint of further improving barrier properties, it is preferable that the (meth)acrylate has two or more ethylenically unsaturated double bonds in one molecule. In this case, a compound having a cyclic aliphatic hydrocarbon group and two or more ethylenically unsaturated double bonds can be mixed with a compound having a cyclic aliphatic hydrocarbon group and one ethylenically unsaturated double bond.

[0112] The cyclic aliphatic hydrocarbon group is preferably a group derived from an alicyclic compound having 7 or more carbon atoms, more preferably a group derived from an alicyclic compound having 10 or more carbon atoms, and even more preferably a group derived from an alicyclic compound having 12 or more carbon atoms. The cyclic aliphatic hydrocarbon group is particularly preferably a group derived from a polycyclic compound, such as a bicyclic or tricyclic compound. More preferably, the central skeleton of the compound described in the claims of Japanese Patent Application Publication No. 2006-215096, the central skeleton of the compound described in Japanese Patent Application Publication No. 2001-10999, or the skeleton of an adamantane derivative is used.

[0113] Examples of cyclic aliphatic hydrocarbon groups include norbornane, tricyclodecane, tetracyclododecane, pentacyclopentadecane, adamantane, and diamantane.

[0114] The cyclic aliphatic hydrocarbon group (including the linking group) is preferably a group represented by any of the following general formulas (I) to (V), more preferably a group represented by the following general formulas (I), (II), or (IV), and even more preferably a group represented by the following general formulas (I) or (IV).

[0115]

[0116] In general formula (I), L and L １ Each of these independently represents a single bond or a linking group with two or more valencies. n represents an integer in the range of 1 to 3.

[0117]

[0118] In general formula (II), L and L １ Each of these independently represents a single bond or a linking group with two or more valencies. n represents an integer in the range of 1 to 2.

[0119]

[0120] In general formula (III), L and L １ Each of these independently represents a single bond or a linking group with two or more valencies. n represents an integer in the range of 1 to 2.

[0121]

[0122] In general formula (IV), L and L １ Each of these independently represents a single bond or a linking group with two or more valents, L ２ This represents a hydrogen atom, a single bond, or a linking group with two or more valent values.

[0123]

[0124] In general formula (V), L and L １ Each of these independently represents a single bond or a linking group with two or more valent values.

[0125] L, L １ and L ２ Examples of divalent or greater linking groups include optionally substituted alkylene groups having 1 to 6 carbon atoms, optionally substituted amide bonds at the N position, optionally substituted urethane bonds, ester bonds, oxycarbonyl groups, ether bonds, and groups obtained by combining two or more of these. In the present invention and this specification, "carbon number" refers to the carbon number of substituted groups, excluding the carbon number of the substituent portion.

[0126] The ethylenically unsaturated double bond is, at least partially, contained within the (meth)acryloyl group.

[0127] Compounds having a cyclic aliphatic hydrocarbon group and two or more ethylenically unsaturated double bonds within the molecule are formed by the bonding of the cyclic aliphatic hydrocarbon group and the group having an ethylenically unsaturated double bond via a linking group.

[0128] The following are specific examples of compounds containing a cyclic aliphatic hydrocarbon group and an ethylenically unsaturated double bond. However, the present invention is not limited to these specific examples.

[0129]

[0130]

[0131]

[0132] The curable composition for forming the protective organic layer may contain at least one or more (meth)acrylates and may optionally contain one or more of the various components commonly used in curable compositions.

[0133] Specific examples of components that may be included in a curable composition for forming a protective organic layer include silicon-based compounds that can function as silane coupling agents.

[0134] Examples of silane coupling agents include those manufactured by Shin-Etsu Silicone Co., Ltd.: KBM-1003 (vinyltrimethoxysilane), KBE-1003 (vinyltriethoxysilane), KBM-1083 (long-chain vinylsilane), X-12-1290 (organosilane), KBM-1403 (p-styryltrimethoxysilane), KBM502 (3-methacryloxypropylmethyldimethoxysilane), KBM503 (3-methacryloxypropyltrimethoxysilane), and KBE503. (3-methacryloxypropyltriethoxysilane), KBM-5803 (long-chain methacrylsilane), KBM5103 (3-acryloxypropyltrimethoxysilane), X-12-1048 (polyfunctional acrylicsilane), X-12-1333A (polymerizable silane), X-12-1050 (polyfunctional acrylicsilane), X-12-1303MS (short-chain methacrylsilane), KBM-802 (3-mercaptopropylmethyldimethoxysilane), KBM-803 (3-mercaptopropyl X-12-1307 (Topropyltrimethoxysilane), X-12-1056ES (Mercapto group protected silane coupling agent), X-12-1154 (Polyfunctional mercaptosilane), KBE-9007N (3-Isocyanatetopropyltriethoxysilane), X-12-1159L (Polyfunctional isocyanate silane), X-12-1195 (The isocyanate group of 3-Isocyanatetopropyltriethoxysilane is protected with ethanol) X-12-1293 (3-isocyanatetopropyltriethoxysilane with isocyanate group protected with caprolactam), X-12-1308ES (3-isocyanatetopropyltriethoxysilane with isocyanate group protected with 3,5-dimethylpyrazole), X-12-967C (3-trimethoxysilylpropyl succinic anhydride), X-12-1135 (carboxyl group-containing aqueous silane coupling agent), KBM-303 (2-(3,4-Epoxycyclohexyl)ethyltrimethoxysilane), KBM-402 (3-glycidoxypropylmethyldimethoxysilane), KBM-403 (3-glycidoxypropyltrimethoxysilane), KBE-402 (3-glycidoxypropylmethyldiethoxysilane), KBE-403 (3-glycidoxypropyltriethoxysilane), X-12-981S (polyfunctional epoxysilane), X-12-984S (polyfunctional epoxysilane), KBM-4803 (long-chain epoxysilane), KBM-602 (N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane), KBM-603 (N-2-(aminoethyl)-3-aminopropyltrimethoxysilane), KBM-903 (3-aminopropyltrimethyl Examples include toxysilane, KBE-903 (3-aminopropyltriethoxysilane), KBM-6103 (N-2-(aminoethyl)-aminomethyltrimethoxylane), KBP-64 (ethylenediamino group-containing aqueous silane coupling agent), KBP-90 (amino group-containing aqueous silane coupling agent), KBE-9103P (silane with chemitin structure), X-12-1172ES (silane with chemitin structure), X-12-972F (polyfunctional aminosilane), KBM-6803 (long-chain ethylenediaminesilane), X-12-1214A (benzotriazole group-containing trimethoxysilane), X-12-1116 (chelate-functional trimethoxysilane), N,N-dimethylaminopropyltrimethoxysilane, etc.

[0135] Examples of silane coupling agents include alkoxysilane compounds having a (meth)acryloyl group, such as vinyltriethoxylan, 3-methacryloxypropyltrimethoxysilane, and 3-acryloxypropyltrimethoxysilane.

[0136] Examples of silane coupling agents include alkoxysilane compounds having an isocyanate group and / or a blocked isocyanate group. Specific examples of such alkoxysilane compounds include the following: Shin-Etsu Silicone Co., Ltd.: KBE-9007N (3-isocyanate-propyltriethoxysilane), X-12-1159L (polyfunctional isocyanate silane), X-12-1195 (3-isocyanate-propyltriethoxysilane with isocyanate group protected with ethanol), X-12-1293 (3-isocyanate-propyltriethoxysilane with isocyanate group protected with caprolactam), X-12-1308ES (3-isocyanate-propyltriethoxysilane with isocyanate group protected with 3,5-dimethylpyrazole), etc.

[0137] Examples of silane coupling agents include alkoxysilane compounds having an amino group. Specific examples of such alkoxysilane compounds include the following: Shin-Etsu Silicone Co., Ltd.: KBM-602 (N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane), KBM-603 (N-2-(aminoethyl)-3-aminopropyltrimethoxysilane), KBM-903 (3-aminopropyltrimethoxysilane), KBE-903 (3-aminopropyltriethoxysilane), KBM-6103 (N-2-(aminoethyl)-aminomethyltrimethoxysilane), KBP-64 (ethylenediamino group-containing aqueous silane coupling agent), KBP-90 (amino group-containing aqueous silane coupling agent), X-12-972F (polyfunctional aminosilane), N,N-dimethylaminopropyltrimethoxysilane, etc.

[0138] The inclusion of a silane coupling agent in the protective organic layer is preferable from the viewpoint of enhancing adhesion between the protective organic layer and the inorganic layer. From the viewpoint of further improving adhesion, a silane coupling agent having hydrogen bonding groups such as amino groups and hydroxyl groups is more preferable. Furthermore, from the viewpoint of increasing the density of the protective organic layer, a silane coupling agent having a (meth)acryloyl group is preferable.

[0139] The content of the silane coupling agent in the curable composition for forming a protective organic layer can be, for example, 0.10% by mass or more and 10.00% by mass or less, based on the total amount of the composition.

[0140] From the viewpoint of increasing the depth to which Is × 1 / 10 is obtained, it is preferable that the elastic modulus of the protective organic layer be 8.0 GP or less, more preferably 7.0 GPa or less, and even more preferably 6.0 GPa or less. From the viewpoint of increasing the depth to which Is × 1 / 10 is obtained even further, in the above wavelength conversion member, it is preferable that the elastic modulus of at least one of the protective organic layer of one of the two substrates and the protective organic layer of the other is 7.0 GPa or less, and more preferably that the elastic modulus of both is 7.0 GPa or less. It is even more preferable that the elastic modulus of at least one of the protective organic layer of one of the two substrates and the protective organic layer of the other is 6.0 GPa or less, and even more preferably that the elastic modulus of both is 6.0 GPa or less. Furthermore, the elastic modulus of one or both of the protective organic layers of the protective organic layer of one of the two substrates and the protective organic layer of the other can be, for example, 1.0 GPa or more, 2.0 GPa or more, or 3.0 GPa or more.

[0141] In the present invention and this specification, the elastic modulus of the protective organic layer is determined by the following method. A cross-section is prepared of the wavelength conversion member to be measured using a rotary microtome. After conditioning the prepared sample by placing it in an environment of 25°C and 60% relative humidity for at least one hour, the elastic modulus is measured in the same environment. Focus curve measurement is performed on the cross-section of the sample to be measured using an AFM (Atomic Force Microscope). For example, an AFM Infinity manufactured by Asylum can be used as the AFM, and an AC160TS manufactured by Asylum can be used as the cantilever. In a randomly selected area of ​​the protective organic layer portion of the cross-section, measurements are taken at five locations with a measurement area of ​​3 μm × 3 μm at a measurement interval of 20 nm. The arithmetic mean of the elastic modulus obtained at one location (a measurement area of ​​3 μm × 3 μm) is taken as the elastic modulus at that location, and the arithmetic mean of the elastic moduli at the five locations is taken as the elastic modulus of the protective organic layer. The elastic modulus of the protective organic layer can be controlled, for example, by the functional group equivalent and reaction rate of the (meth)acrylate contained in the curable composition for forming the protective organic layer.

[0142] For the underlying organic layer, refer to paragraphs 0020 to 0042 of Japanese Patent Publication No. 2007-290369 and paragraphs 0074 to 0105 of Japanese Patent Publication No. 2005-096108. Also, for the underlying organic layer, refer to the previous description concerning the protective organic layer. Furthermore, in one embodiment, the underlying organic layer may include a cardopolymer. For details on the cardopolymer, refer to paragraphs 0085 to 0095 of Japanese Patent Publication No. 2005-096108.

[0143] Each organic layer, either the protective organic layer or the underlayment organic layer, can be formed on the surface of an adjacent layer or on the support surface by a known method for film formation using a curable composition. The thickness of each organic layer is preferably in the range of 0.1 to 10 μm.

[0144] Regarding the transmittance of the substrate, it is preferable that the total light transmittance in the visible light region be 80% or higher, and more preferably 85% or higher. The visible light region is the wavelength region of 380 to 780 nm, and the total light transmittance represents the arithmetic mean of the light transmittance across the visible light region.

[0145] The oxygen permeability of the substrate is 1 cc / (m³). ２ It is preferable that the oxygen permeability of the substrate is less than or equal to (day·atm). More preferably, it is 0.1 cc / (m³). ２ (day / atm) or less, more preferably 0.01 cc / (m) ２ It is less than or equal to (day atm), and more preferably 0.001 cc / (m³). ２ The temperature is less than or equal to (day / atm). It is also preferable that the substrate has water vapor barrier properties to block water vapor.

[0146] For cutting wavelength conversion members into desired shapes such as product shapes, known techniques can be applied. For example, die cutting can be used to cut wavelength conversion members into desired shapes. In die cutting, a die is used with a punching machine to cut from a roll of material. Generally, a die called a Thomson blade can be used as the die.

[0147] [Light-emitting device] One aspect of the present invention relates to a light-emitting device including the above-mentioned wavelength conversion member and light source.

[0148] The above-mentioned light-emitting device can, in one embodiment, be a backlight unit. The backlight unit can, for example, function as a light-emitting device for a liquid crystal display device.

[0149] An example of a backlight unit will be described below with reference to the drawings. Figure 11 is a schematic diagram showing the general configuration of a backlight unit.

[0150] As shown in Figure 11, the backlight unit 50 emits primary light (blue light L ＢThe device comprises a planar light source 52C consisting of a light source 52A that emits light and a light guide plate 52B that guides and emits the primary light emitted from the light source 52A; a wavelength conversion member 54 disposed on the planar light source 52C; a reflector 56A and a retroreflective member 56B disposed opposite the wavelength conversion member 54 with the planar light source 52C in between. In Figure 11, the reflector 56A, light guide plate 52B, wavelength conversion member 54 and retroreflective member 56B are shown spaced apart, but in reality, they may be formed in close contact with each other.

[0151] The wavelength conversion member 54 receives primary light L emitted from the planar light source 52C. Ｂ At least a portion of this is used as excitation light, and fluorescence is emitted, and secondary light (green light L) consisting of this fluorescence is emitted. Ｇ , red light L Ｒ ) and the primary light L that has passed through the wavelength conversion member 54 Ｂ It emits blue light L. For example, the wavelength conversion member 54 emits blue light L. Ｂ Green light L Ｇ A phosphor that emits light and red light L Ｒ This wavelength conversion member is composed of a wavelength conversion layer containing a phosphor that emits light, sandwiched between two substrates.

[0152] In Figure 11, L emitted from the wavelength conversion member 54 Ｂ , L Ｇ and L Ｒ The light is incident on the retroreflective member 56B, and each incident light is repeatedly reflected between the retroreflective member 56B and the reflector 56A, allowing it to pass through the wavelength conversion member 54 many times. As a result, the wavelength conversion member 54 receives a sufficient amount of excitation light (blue light L Ｂ ) is absorbed by the phosphor 24 in the wavelength conversion layer 16, and a sufficient amount of fluorescence (L Ｇ , L Ｒ ) emits light, and white light L is emitted from the retroreflective member 56B. Ｗ It is materialized and launched.

[0153] From the viewpoint of achieving high brightness and high color reproduction, it is preferable to use a multi-wavelength light source as the backlight unit 50. For example, it is preferable to emit blue light having a emission center wavelength in the 430-480 nm wavelength band and an emission intensity peak with a full width at half maximum of 100 nm or less, green light having a emission center wavelength in the 500-600 nm wavelength band and an emission intensity peak with a full width at half maximum of 100 nm or less, and red light having a emission center wavelength in the 600-680 nm wavelength band and an emission intensity peak with an emission intensity peak with a full width at half maximum of 100 nm or less.

[0154] From the viewpoint of further improving brightness and color reproducibility, the wavelength range of the blue light emitted by the backlight unit 50 is more preferably 440 to 460 nm. From a similar viewpoint, the wavelength range of the green light emitted by the backlight unit 50 is more preferably 520 to 560 nm, and more preferably 520 to 545 nm. Also from a similar viewpoint, the wavelength range of the red light emitted by the backlight unit 50 is more preferably 610 to 640 nm. Also from a similar viewpoint, the full width at half maximum (FWHM) of the emission intensity of the blue, green, and red light emitted by the backlight unit 50 is more preferably 80 nm or less, more preferably 50 nm or less, even more preferably 40 nm or less, and particularly preferably 30 nm or less. Among these, the FWHM of the emission intensity of the blue light is particularly preferably 25 nm or less.

[0155] The light source 52A can be, for example, a blue light-emitting diode. A blue light-emitting diode can emit blue light having a emission center wavelength in the wavelength band of 430 to 480 nm, for example. Alternatively, an ultraviolet light-emitting diode that emits ultraviolet light may be used as the light source 52A. In addition to light-emitting diodes, a laser light source or the like can be used as the light source 52A. If a light source that emits ultraviolet light is provided, the wavelength conversion layer of the wavelength conversion member 54 may include a phosphor that emits blue light, a phosphor that emits green light, and a phosphor that emits red light when irradiated with ultraviolet light.

[0156] The planar light source 52C may be a planar light source consisting of a light source 52A and a light guide plate 52B that guides and emits the primary light emitted from the light source 52A, as shown in Figure 11, or it may be a planar light source in which the light source 52A is arranged in a plane parallel to the wavelength conversion member 54 and a diffuser plate is provided instead of the light guide plate 52B. The former planar light source is generally called an edge-lit type, and the latter planar light source is generally called a direct-lit type. In the above explanation, the case in which a planar light source is used as the light source has been described as an example. However, light sources other than planar light sources can also be used as the light source.

[0157] <Backlight Unit Configuration> Figure 11 describes an edge-lit backlight unit configuration, which consists of a light guide plate and a reflector plate. However, the backlight unit configuration may also be a direct-lit type. A known type of light guide plate can be used.

[0158] Furthermore, there are no particular restrictions on the reflector 56A, and known reflectors can be used; refer to Japanese Patent No. 3416302, Japanese Patent No. 3363565, Japanese Patent No. 4091978, Japanese Patent No. 3448626, etc.

[0159] The retroreflective member 56B may be composed of known diffusers and diffusers, prism sheets (for example, the BEF series manufactured by Sumitomo 3M), and light guides. For the configuration of the retroreflective member 56B, refer to Japanese Patent No. 3416302, Japanese Patent No. 3363565, Japanese Patent No. 4091978, Japanese Patent No. 3448626, etc.

[0160] [Liquid crystal display device] One aspect of the present invention relates to a liquid crystal display device including the above-mentioned light-emitting device and liquid crystal cell.

[0161] An example of a liquid crystal display device will be described below with reference to the drawings. Figure 12 is a schematic diagram showing the general configuration of a liquid crystal display device.

[0162] As shown in Figure 12, the liquid crystal display device 60 comprises a backlight unit 50 as a light-emitting device and a liquid crystal cell unit 62 arranged opposite to the retroreflective member side of the backlight unit. The backlight unit 50 emits white light L Ｗ It can fire.

[0163] As shown in Figure 12, the liquid crystal cell unit 62 has a configuration in which a liquid crystal cell 64 is sandwiched between polarizing plates 68 and 70, and the polarizing plates 68 and 70 have their two main surfaces of the polarizers 72 and 74 protected by polarizing plate protective films 76 and 78, and 82 and 84, respectively.

[0164] There are no particular limitations on the liquid crystal cells 64, polarizing plates 68 and 70, and their components that constitute the liquid crystal display device 60; products manufactured by known methods and commercially available products can be used. It is also possible to provide known intermediate layers, such as adhesive layers, between each layer.

[0165] There are no particular restrictions on the driving mode of the liquid crystal cell 64, and various modes such as twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA), in-plane switching (IPS), and optically compensated bend cell (OCB) can be used. The liquid crystal cell is preferably in VA mode, OCB mode, IPS mode, or TN mode. However, it is not limited to these. As an example of the configuration of a liquid crystal display device in VA mode, the configuration shown in Figure 2 of Japanese Patent Application Publication No. 2008-262161 can be cited. However, there are no particular restrictions on the specific configuration of the liquid crystal display device, and known configurations can be adopted.

[0166] The liquid crystal display device 60 may further have additional functional layers such as optical compensation members and adhesive layers, as needed. In addition, the liquid crystal display device 60 may have surface layers such as a forward scattering layer, primer layer, antistatic layer, undercoat layer, etc., along with (or in place of) a color filter substrate, thin transistor substrate, lens film, diffusion sheet, hard coat layer, anti-reflective layer, low-reflection layer, anti-glare layer, etc.

[0167] The polarizing plate 68 on the backlight unit 50 side may have a phase difference film as the polarizing plate protective film 78 on the liquid crystal cell 64 side. As such a phase difference film, known cellulose acylate films and the like can be used.

[0168] The present invention will be described in more detail below based on examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the examples shown below. The "%" mentioned below refers to mass percent.

[0169] [Example 1] <Preparation of Substrate A> As Substrate A, a substrate was prepared in which a base organic layer, an inorganic layer, and a protective organic layer were formed on one side of the support as follows. A polyethylene terephthalate (PET) film (Cosmoshine A4360, manufactured by Toyobo Co., Ltd., 50 μm thick) was used as the support.

[0170] (Formation of the underlying organic layer) Tricyclodecanedimethanol diacrylate (TMPTA, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) and a photopolymerization initiator (ESACURE KTO46, manufactured by Lamberti) were prepared, weighed in a mass ratio of 95:5, and dissolved in methyl ethyl ketone to create a coating solution with a solid content of 15% for forming the underlying organic layer. This coating solution was applied onto the support (PET film) using a die coater in a roll-to-roll manner and passed through a drying zone at 50°C for 3 minutes. After that, ultraviolet light was irradiated under a nitrogen atmosphere (cumulative irradiation dose approximately 600 mJ / cm²). ２ The coating solution was cured by (and then rolled up). The thickness of the formed organic base layer was 1.0 μm.

[0171] (Formation of the Inorganic Layer) Next, a silicon nitride film was formed as an inorganic layer on the surface of the underlying organic layer using a CVD (Chemical Vapor Deposition) apparatus that performs film formation by roll-to-roll. Silane gas (flow rate 160 sccm (Standard Cubic Centimeter per Minute)), ammonia gas (flow rate 370 sccm), hydrogen gas (flow rate 590 sccm), and nitrogen gas (flow rate 240 sccm) were used as raw material gases. A high-frequency power supply with a frequency of 13.56 MHz was used as the power source. The film formation pressure was 40 Pa (Pascals), and the target film thickness was 50 nm.

[0172] (Formation of protective organic layer) Furthermore, a protective organic layer was laminated onto the surface of the inorganic layer. 92.0 parts by mass of tricyclodecanedimethanol diacrylate (A-DCP, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) was mixed with 5.0 parts by mass of a photopolymerization initiator (IRGACURE 184, manufactured by BASF) and 3.0 parts by mass of a silane coupling agent (X-12-1116, manufactured by Shin-Etsu Silicone Co., Ltd.). These were dissolved in methyl ethyl ketone to create a coating solution with a solid content of 15% for forming the protective organic layer. This coating solution was applied directly to the surface of the inorganic layer using a die coater in a roll-to-roll manner and passed through a drying zone at 100°C for 3 minutes. After that, the material was wrapped around a heat roll heated to a surface temperature of 60°C and transported while being cured by irradiation with ultraviolet light (UV (ultraviolet) irradiation amount (cumulative irradiation amount): see Table 2), and then wound up. The thickness of the formed protective organic layer was 0.5 μm.

[0173] In this way, a substrate A with the layer structure shown in Figure 1 was prepared. The oxygen permeability of the prepared substrate A was measured using a MOCON OX-TRAN 2 / 20 under conditions of a measurement temperature of 23°C and a relative humidity of 90%, and the oxygen permeability was found to be 2.5 × 10⁻⁶. －３ cc / (m ２ It was less than (day ATM).

[0174] <Preparation of Phosphor-Containing Curable Composition> A phosphor-containing curable composition was prepared by mixing the components listed in Table 1. In Table 1, the unit is mass%.

[0175]

[0176] Details of the various components in Table 1 are as follows: (Meth)acrylate: Tricyclodecanedimethanol diacrylate (NK Ester A-DCP, manufactured by Shin Nakamura Chemical Industry Co., Ltd.) Thiol compound: Trimethylolpropanetris (3-mercaptopropionate) (TMMP, manufactured by SC Organic Chemicals Co., Ltd.) Photopolymerization initiator: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Omnirad TPO, manufactured by IGM RESINS Inc.) Phosphor: As a quantum dot phosphor IBOA (isobornyl acrylate) dispersion, a CdSe / ZnS (core / shell) dispersion (Gen3.5 QD Concentrate, Nanosys Inc.) was used. Isobornyl acrylate was used as the dispersion medium for this CdSe / ZnS (core / shell) dispersion. The CdSe / ZnS (core / shell) dispersion contains 90% by mass or more of isobornyl acrylate. Carboxylic acid: Fujifilm Wako Pure Chemical Industries Ltd. White acetate pigment: Titanium dioxide (Chemours, Typure R-706, particle size 0.36 μm) was used. The surface of the titanium dioxide is provided with a first metal oxide layer containing silicon dioxide, a second metal oxide layer containing aluminum oxide, and an organic layer containing a polyol compound, in the order of the first metal oxide layer, the second metal oxide layer, and the organic layer.

[0177] <Fabrication of Wavelength Conversion Components> The phosphor-containing curable composition shown in Table 1 was applied to the protective organic layer side of substrate A as the first substrate to form a coating layer. Then, substrate A was prepared as the second substrate, and after laminating it so that the protective organic layer was in contact with the coating layer of the phosphor-containing curable composition, the phosphor-containing curable composition was photocured while under pressure with a laminator to produce a wavelength conversion component. The photocuring of the phosphor-containing curable composition was performed using an air-cooled metal halide lamp (manufactured by I-Graphics Co., Ltd.) with ultraviolet light at 600 mJ / cm from the first substrate side. ２ The procedure was performed by irradiating with the specified exposure dose. The laminator pressure was adjusted to set the thickness of the wavelength conversion layer to 50 μm.

[0178] [Examples 2-14, Comparative Examples 1-3] Wavelength conversion members were manufactured by the method described for Example 1, except that the items shown in Table 2 were changed as shown in Table 2. In the examples where the temperature and time are indicated in the "Post-Lamination Heat Treatment" column, after pressure bonding with a laminator, heat treatment was performed in a heating furnace at the indicated ambient temperature for the indicated time, and then the phosphor-containing curable composition was photocured as described for Example 1. The second substrate of Example 4 was manufactured by forming a base organic layer on a support, and then laminating a protective organic layer without forming an inorganic layer.

[0179] In Table 2, "A-DCP" listed in the column for the protective organic layer is tricyclodecanedimethanol diacrylate (A-DCP manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), as previously stated. In the examples and comparative examples where substances other than A-DCP are listed, the listed (meth)acrylate was used in the same amount as A-DCP used in the formation of the protective organic layer in Example 1. "A-200" is polyethylene glycol diacrylate (A-200 manufactured by Shin-Nakamura Chemical Industry Co., Ltd.). "DPCA-60" is the acrylate of the adduct of dipentaerythritol and ε-caprolactone (KAYARAD DPCA-60 manufactured by Nippon Kayaku Co., Ltd.). "DPCA-30" is the acrylate of the adduct of dipentaerythritol and ε-caprolactone (KAYARAD DPCA-30 manufactured by Nippon Kayaku Co., Ltd.). "DPCA-20" is an acrylate compound of the adduct between dipentaerythritol and ε-caprolactone (KAYARAD DPCA-20, manufactured by Nippon Kayaku Co., Ltd.). "DPHA" is dipentaerythritol hexaacrylate (KAYARAD DPHA, manufactured by Nippon Kayaku Co., Ltd.).

[0180] [Evaluation Method] <Depth at which Is × 1 / 10 occurs> For each of Examples 1 to 14 and Comparative Examples 1 to 3, the depth at which Is × 1 / 10 occurs was determined for the protective organic layer of the first substrate and the protective organic layer of the second substrate, respectively, using the method described above. The details are as follows: For each of Examples 1 to 14 and Comparative Examples 1 to 3, multiple test pieces were cut from the fabricated wavelength conversion members. The multiple test pieces were divided into two groups. One group was used to determine the depth at which Is × 1 / 10 occurs for the protective organic layer of the second substrate, with the first substrate fixed on a glass plate. The other group was used to determine the depth at which Is × 1 / 10 occurs for the protective organic layer of the first substrate, with the second substrate fixed on a glass plate. For each group, specimens in which the thickness of the protective organic layer observed in the cross-sectional SEM image was approximately the same as the thickness of the protective organic layer formed for the fabrication of the wavelength conversion member were selected as specimens in which the delamination surface near the interface between the protective organic layer and the wavelength conversion layer was exposed on the outermost surface, and these specimens were used for TOF-SIMS measurement. An NT cutter with a blade angle of 30° manufactured by NT Corporation was used as the cutter. Polyester adhesive tape No. 31B manufactured by Nitto Denko Corporation was used as the adhesive tape. A TRIFT V nanoTOF II manufactured by Ulvac PHI was used as the TOF-SIMS instrument. In the selected specimens, it was confirmed that fragments originating from the silane coupling agent of the protective organic layer were detected in the TOF-SIMS posi or nega measurement at a depth of zero.

[0181] <Elastic Modulus of Protective Organic Layer> For each of Examples 1 to 14 and Comparative Examples 1 to 3, test specimens were cut from the fabricated wavelength conversion members. Using the cut test specimens, the elastic modulus of the protective organic layer of the first substrate and the protective organic layer of the second substrate were determined by the method described above. The arithmetic mean of the elastic modulus of five locations in the protective organic layer of the first substrate was taken as the elastic modulus of the protective organic layer of the first substrate. The arithmetic mean of the elastic modulus of five locations in the protective organic layer of the second substrate was taken as the elastic modulus of the protective organic layer of the second substrate. An AFM Infinity manufactured by Asylum was used as the AFM, and an AC160TS manufactured by Asylum was used as the cantilever.

[0182] <Frequency of delamination> For each of Examples 1 to 14 and Comparative Examples 1 to 3, the prepared wavelength conversion members were conditioned for 24 hours in an environment with an ambient temperature of 25°C and a relative humidity of 60%. Then, 100 punched-out samples were prepared by repeatedly punching out four 4cm x 4cm pieces from the first substrate side 25 times using a 43° cutting angle die (manufactured by Nakayama Co., Ltd.). For each of the 100 punched-out samples, each edge was observed with a magnifying glass, and the presence or absence of delamination was determined according to the following evaluation criteria. The term "lifting" below refers to a void existing in at least one of the spaces between the protective organic layer and the wavelength conversion layer of the first substrate, and between the protective organic layer and the wavelength conversion layer of the second substrate. Furthermore, the frequency of delamination was ranked based on the ratio of the number of samples with delamination to the total number of samples (100) according to the following criteria. If the rating is AAA to C, it can be said that delamination is suppressed at the cut edge (punched edge). (Evaluation criteria) No delamination: No lifting occurs, or lifting occurs, but the lifting is less than 200 μm in length from the punched edge. Delamination occurs: One or more lifting areas of 200 μm or more in length occur from the punched edge. (Ranking criteria for occurrence frequency) AAA: Delamination frequency is 0% AA: Delamination frequency is greater than 0% and 5% or less A: Delamination frequency is greater than 5% and 10% or less B: Delamination frequency is greater than 10% and 20% or less C: Delamination frequency is greater than 20% and 30% or less D: Delamination frequency is greater than 30% and 70% or less E: Delamination frequency is greater than 70%

[0183] <Decrease in edge brightness over time> For each of Examples 1 to 14 and Comparative Examples 1 to 3, the fabricated wavelength conversion member was used as the raw material, and the wavelength conversion member was cut out by die-cutting. The cut wavelength conversion member was stored for 500 hours in a high-temperature, high-humidity environment at a temperature of 65°C and a relative humidity of 90%. A commercially available liquid crystal display device (Amazon tablet device product name "Kindle® Fire HDX 7") equipped with a blue light source in its backlight unit was disassembled, and the backlight unit was removed. The wavelength conversion member stored in the high-temperature, high-humidity environment described above was incorporated in place of the wavelength conversion film QDEF (Quantum Dot Enhancement Film) that was incorporated into the backlight unit. Blue light was irradiated from one substrate side, and the transmitted light from the other substrate side was observed with an optical microscope. The maximum width from the edge of the wavelength conversion member where the wavelength conversion layer had deteriorated and was not emitting light (edge ​​non-emitting width) was measured. The degree of time-dependent reduction in edge brightness was evaluated based on the measured values ​​of the non-luminescent width at the edges obtained in this way, according to the following evaluation criteria. If the result is AAA to C, it can be said that the time-dependent reduction in edge brightness is suppressed. By suppressing delamination at the cut edge, the time-dependent reduction in edge brightness can be suppressed. Furthermore, by having high barrier properties that suppress the intrusion of oxygen and / or water into the wavelength conversion layer in the wavelength conversion member, the time-dependent reduction in edge brightness can be further suppressed. (Evaluation Criteria) AAA: Less than 250 μm AA: 250 μm or more and less than 500 μm A: 500 μm or more and less than 1000 μm B: 1000 μm or more and less than 2000 μm C: 2000 μm or more and less than 3000 μm D: 3000 μm or more

[0184] The results are shown in Table 2.

[0185]

[0186] From the evaluation results of the depth at which the protective organic layer is Is × 1 / 10 and the frequency of delamination shown in Table 2, it can be confirmed that it is preferable for the protective organic layer to satisfy condition (1), and more preferable for it to satisfy condition (1-1).

[0187] One aspect of the present invention is useful in the field of liquid crystal display devices.

[0188] 1, 2 Substrate 3 Wavelength conversion layer 4 Support 5 Underlying organic layer 6 Inorganic layer 7 Protective organic layer 10 Wavelength conversion member 12 First substrate 12a, 14a Support 12b, 14b Barrier layer 14 Second substrate 16 Wavelength conversion layer 18 Resin layer 18a Recess 20 Phosphor-containing region 24, 24e Phosphor 26 Matrix 34 Underlying organic layer 36 Inorganic layer 38 Protective organic layer 50 Backlight unit 52A Light source 52B Light guide plate 52C Planar light source 54 Wavelength conversion member 56A Reflector 56B Retroreflective member 60 Liquid crystal display device 62 Liquid crystal cell unit 64 Liquid crystal cell 68, 70 Polarizing plate 72, 74 Polarizer 76, 78, 82, 84 Polarizing plate protective film L1 Resin layer forming composition M Mold

Claims

1. A wavelength conversion member having a wavelength conversion layer between two substrates, wherein the wavelength conversion layer is a layer containing a cured product obtained by curing a curable composition containing at least a phosphor and a thiol compound, the two substrates each have a protective organic layer in contact with the wavelength conversion layer, the protective organic layer is a layer containing a cured product obtained by curing a curable composition containing at least (meth)acrylate, and at least one of the protective organic layers of one of the two substrates and the other satisfy the following condition (1): Condition (1): When the protective organic layer and the wavelength conversion layer are peeled apart and TOF-SIMS in the depth direction on the protective organic layer side is measured, thiols are detected from the peeled surface on the protective organic layer side, and the depth at which the thiol-derived fragment intensity first becomes Is × 1 / 10, when the thiol-derived fragment intensity of the peeled surface is Is, is 3 nm or more.

2. The wavelength conversion member according to claim 1, wherein both the protective organic layer on one of the two substrates and the protective organic layer on the other satisfy condition (1).

3. The wavelength conversion member according to claim 1, wherein at least one of the protective organic layers on one of the two substrates satisfies the following condition (1-1): Condition (1-1): When the protective organic layer and the wavelength conversion layer are peeled off and TOF-SIMS in the depth direction on the protective organic layer side is measured, thiols are detected from the peeled surface on the protective organic layer side, and the depth at which the thiol-derived fragment intensity first becomes Is × 1 / 10, when the thiol-derived fragment intensity on the peeled surface is Is, is 5 nm or more.

4. The wavelength conversion member according to claim 3, wherein both the protective organic layer on one of the two substrates and the protective organic layer on the other satisfy condition (1-1).

5. The wavelength conversion member according to claim 1, wherein the elastic modulus of at least one of the protective organic layer on one of the two substrates and the protective organic layer on the other is 7.0 GPa or less.

6. The wavelength conversion member according to claim 1, wherein the elastic modulus of both the protective organic layer on one of the two substrates and the protective organic layer on the other substrate are 7.0 GPa or less.

7. The wavelength conversion member according to claim 1, wherein the (meth)acrylate is a compound containing a cyclic aliphatic hydrocarbon group and an ethylenically unsaturated double bond.

8. The wavelength conversion member according to claim 1, wherein the phosphor comprises quantum dots.

9. The wavelength conversion member according to claim 4, wherein the elastic modulus of both the protective organic layer on one of the two substrates and the protective organic layer on the other substrate are 7.0 GPa or less, the (meth)acrylate is a compound containing a cyclic aliphatic hydrocarbon group and an ethylenically unsaturated double bond, and the phosphor contains quantum dots.

10. A light-emitting device comprising a wavelength conversion member according to any one of claims 1 to 9 and a light source.

11. A liquid crystal display device comprising the light-emitting device according to claim 10 and a liquid crystal cell.

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