Fluorescent sheet

Abstract

To provide a material capable of forming a phosphor layer by a simple process without using a coating material.SOLUTION: A phosphor sheet comprising a thermosetting resin composition in a B-stage state, the thermosetting resin composition comprising phosphor particles and a curable resin component, wherein the phosphor sheet has a thickness of 20 to 150 μm. The lighting device includes a fluorescent layer which is a cured product of the phosphor sheet, and a light-emitting element installed on a surface of the fluorescent layer opposite to the insulating substrate.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a phosphor sheet and a lighting device. [Background technology]

[0002] Various developments are underway for lighting devices using LEDs (Light Emitting Devices). Not only the development of LEDs themselves, but also the development of mounting boards that include LEDs is also known.

[0003] For example, Example 2 of Patent Document 1 describes the following: (i) a glass binder paint containing 30 vol% phosphor was applied to the surface of a glass substrate to form a phosphor layer with a thickness of 200 μm; (ii) a plurality of CSPs were bonded onto the glass substrate to obtain a mounting substrate for LED lighting; and (iii) when electricity was applied to the mounting substrate, the problems of glare and multiple shadows were reduced despite light being emitted from the plurality of CSPs. (CSP is an abbreviation for Chip Scale Package or Chip Size Package, and is a package-less design in which the LED chip is wrapped in phosphor resin, consisting of only the LED chip and phosphor resin.) [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 093339 Summary of the Invention [Problem to be solved by the invention]

[0005] In Example 2 of Patent Document 1, a phosphor layer 200 μm thick is formed on a glass substrate using a "glass binder paint" containing phosphor. However, a sintering process at high temperatures is usually required to fully harden the glass binder paint. Therefore, Example 2 of Patent Document 1 leaves room for improvement in terms of the ease with which the phosphor layer can be applied. In addition, the housing / substrate to which the glass binder paint is applied is subject to limitations such as heat resistance and optimization of the expansion coefficient. Furthermore, forming a phosphor layer using a "paint" poses challenges, such as a complicated process and the need to solve the problem of paint dripping.

[0006] The present invention has been made in view of the above circumstances, and one of the objects of the present invention is to provide a material that enables a phosphor layer to be formed by a simple process without using paint. [Means for solving the problem]

[0007] As a result of extensive research, the present inventors have completed the invention provided below and solved the above-mentioned problems.

[0008] 1. A phosphor sheet having a thickness of 20 to 150 μm, which comprises a thermosetting resin composition in a B-stage state, and which contains phosphor particles and a curable resin component. 2. 1. The phosphor sheet according to claim 1, The phosphor sheet, wherein the curable resin component comprises at least one resin selected from the group consisting of an epoxy resin and a silicone resin. 3. 1. The phosphor sheet according to 1. or 2., A phosphor sheet with through holes. 4. The phosphor sheet according to any one of 1. to 3., A phosphor sheet having a phosphor particle content of 25 vol% or more and 60 vol% or less. 5. The phosphor sheet according to any one of 1. to 4., The phosphor sheet includes phosphor particles capable of converting blue light into light with a wavelength longer than that of the blue light. 6. The phosphor sheet according to any one of 1. to 5., The median diameter D of the phosphor particles 50 A phosphor sheet having a thickness of 1 μm or more and 20 μm or less. 7. The phosphor sheet according to any one of 1. to 6., A phosphor sheet in which two or more maxima are observed in the particle size distribution curve of the phosphor particles. 8. A phosphor sheet according to any one of 1. to 7., A phosphor sheet in which a particle size distribution curve of the phosphor particles shows a maximum in both a particle size region of 1 μm or more and 6 μm or less and a particle size region of 10 μm or more and 25 μm or less. 9. A phosphor sheet according to any one of 1. to 8., The phosphor particles are CASN-based phosphors, SCASN-based phosphors, La3Si6N 11 a phosphor sheet containing one or more selected from the group consisting of a Ba2Si5N8-based phosphor, an Sr2Si5N8-based phosphor, an α-sialon-based phosphor, a β-sialon-based phosphor, an LuAG-based phosphor, and a YAG-based phosphor. 10. an insulating substrate; a fluorescent layer formed on one surface of the insulating substrate, the fluorescent layer being a cured product of the phosphor sheet according to any one of 1. to 9.; a light-emitting element disposed on the surface of the fluorescent layer opposite to the insulating substrate. 11. 10. The lighting device according to claim 10, The lighting device further comprises a white layer between the insulating substrate and the fluorescent layer. 12. 10. or 11. The lighting device according to claim 11, A lighting device in which a plurality of the light-emitting elements are installed. 13. The lighting device according to any one of items 10 to 12, The light emitting element does not have a reflector. [Effects of the Invention]

[0009] According to the present invention, a phosphor layer can be formed by a simple process without using paint. [Brief explanation of the drawings]

[0010] [Figure 1] 10A to 10C are diagrams for explaining a manufacturing procedure of the lighting device. [Figure 2] 10A to 10C are diagrams for explaining a manufacturing procedure of the lighting device. [Figure 3] 10A to 10C are diagrams for explaining a manufacturing procedure of the lighting device. [Figure 4] 10A to 10C are diagrams for explaining a manufacturing procedure of the lighting device. [Figure 5] 10A to 10C are diagrams for explaining a manufacturing procedure for the lighting device and the lighting device. [Figure 6] 1A and 1B are diagrams illustrating an LED chip with a reflector and an LED chip without a reflector. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings, similar components are denoted by similar reference numerals and descriptions thereof will be omitted where appropriate. To avoid complexity, (i) when there are multiple identical components in the same drawing, only one of them is given a symbol, and not all of them, or (ii) particularly in Figure 2 and subsequent figures, components similar to those in Figure 1 are not given a symbol again. All drawings are for illustrative purposes only, and the shapes and dimensional ratios of the components in the drawings do not necessarily correspond to the actual products.

[0012] In this specification, unless otherwise specified, the expression "X to Y" in the description of a numerical range means at least X and at most Y. For example, "1 to 5% by mass" means "at least 1% by mass and at most 5% by mass."

[0013] In the description of groups (atomic groups) in this specification, when a notation does not specify whether the group is substituted or unsubstituted, it encompasses both groups having no substituents and groups having a substituent. For example, the term "alkyl group" encompasses not only alkyl groups having no substituents (unsubstituted alkyl groups) but also alkyl groups having a substituent (substituted alkyl groups). In this specification, the term "(meth)acrylic" represents a concept that encompasses both acrylic and methacrylic. The same applies to similar terms such as "(meth)acrylate." Unless otherwise specified, the term "organic group" as used herein means an atomic group obtained by removing one or more hydrogen atoms from an organic compound. For example, a "monovalent organic group" refers to an atomic group obtained by removing one hydrogen atom from any organic compound.

[0014] <Phosphor sheet> The phosphor sheet of this embodiment is made of a thermosetting resin composition in a B-stage state, which contains phosphor particles and a curable resin component. The thickness of the phosphor sheet of this embodiment is usually 20 to 150 μm, preferably 30 to 120 μm, and more preferably 35 to 100 μm.

[0015] The phosphor sheet of this embodiment is in a B-stage state (or, in other words, a semi-cured state), so that its fluidity at temperatures around room temperature is substantially eliminated, allowing it to maintain its shape as a "sheet." The phosphor sheet of this embodiment is in a B-stage state, so that after being placed on a substrate as a sheet, it can be heated (preferably while applying pressure) to adhere sufficiently strongly to the substrate, forming a phosphor layer. Since the application of a liquid coating material is not required, the phosphor layer can be formed by a simpler process than conventional methods. Incidentally, in this specification, the B-stage state includes the state before the C-stage state, i.e., before complete curing. By making the thickness of the phosphor sheet of this embodiment 20 μm or more, the phosphor sheet contains a sufficient amount of phosphor particles, and the light conversion efficiency of the phosphor sheet can be sufficiently increased. Furthermore, by making the thickness of the phosphor sheet of this embodiment 150 μm or less, the time required for thermal curing can be shortened. A phosphor sheet that is not too thick is also preferable in that it facilitates electrical connection (such as soldering) between the light-emitting element and copper wiring in the manufacture of the lighting device described below.

[0016] The phosphor sheet of this embodiment will be described in more detail below.

[0017] (phosphor particles) The phosphor particles contained in the phosphor sheet of this embodiment may be any particles that emit fluorescence in response to light emitted from the light emitting element. Specifically, the phosphor particles may be any particles that can convert blue light into light with a wavelength longer than that of the blue light. Depending on the desired color tone and color temperature, a single type of phosphor particle may be used, or two or more types of phosphor particles may be used in combination.

[0018] The phosphor particles include CASN phosphor, SCASN phosphor, La3Si6N 11 The phosphors may be one or more selected from the group consisting of Sr2Si5N8-based phosphors, Ba2Si5N8-based phosphors, α-sialon-based phosphors, β-sialon-based phosphors, LuAG-based phosphors, and YAG-based phosphors. These phosphors usually contain activating elements such as Eu and Ce.

[0019] The CASN phosphor (a type of nitride phosphor) preferably contains Eu. The CASN phosphor is, for example, represented by the formula CaAlSiN3:Eu 2+ It is expressed as Eu 2+ This refers to a red phosphor that uses as an activator an alkaline earth silicon nitride crystal as a matrix. In the definition of Eu-containing CASN-based phosphors in this specification, Eu-containing SCASN-based phosphors are excluded.

[0020] The SCASN phosphor (a type of nitride phosphor) preferably contains Eu. The SCASN phosphor is, for example, represented by the formula (Sr,Ca)AlSiN3:Eu 2+ It is expressed as Eu 2+ This refers to a red phosphor that uses as an activator a crystal of alkaline earth silicon nitride as a base material.

[0021] La3Si6N 11 The phosphor is specifically La3Si6N 11 :Ce phosphors, etc., which usually convert the blue light from a blue LED into yellow light.

[0022] Specifically, the Sr2Si5N8 phosphor is Sr2Si5N8:Eu 2+ Phosphors and Sr2Si5N8:Ce 3+ These usually convert the wavelength of blue light from a blue LED into yellow to red light.

[0023] A Ba2Si5N8-based phosphor is specifically Ba2Si5N8:Eu, which normally converts the wavelength of blue light from a blue LED into orange to red light.

[0024] The α-sialon phosphor preferably contains Eu. The α-sialon containing Eu is, for example, a phosphor represented by the general formula: M x EU y Si 12-(m+n) Al (m+n) O n N 16-nIt is represented by. In the general formula, M is at least one element containing at least Ca selected from the group consisting of Li, Mg, Ca, Y, and lanthanide elements (excluding La and Ce). When the valence of M is a, ax + 2y = m, where 0 < x ≤ 1.5, 0.3 ≤ m < 4.5, and 0 < n < 2.25.

[0025] The β - type sialon - based phosphor preferably contains Eu. The β - type sialon containing Eu is, for example, represented by the general formula Si 6-z Al z O z N 8-z :Eu 2+ (0 < Z ≤ 4.2), and is a phosphor composed of β - type sialon in which Eu 2+ is solid - dissolved. In the general formula, the Z value and the europium content are not particularly limited. The Z value is, for example, more than 0 and 4.2 or less, and from the viewpoint of further improving the emission intensity of the β - type sialon, it is preferably 0.005 or more and 1.0 or less. Also, the europium content is preferably 0.1 mass% or more and 2.0 mass% or less.

[0026] The LuAG - based phosphor usually means a lutetium aluminum garnet crystal. Considering its application to lighting devices, LuAG is preferably a LuAG:Ce phosphor. More specifically, LuAG can be represented by the composition formula of Lu3Al5O 12 :Ce, but the composition of LuAG does not necessarily have to follow stoichiometry.

[0027] The YAG - based phosphor usually means a yttrium aluminum garnet crystal. Considering its application to lighting devices, the YAG - based phosphor is preferably activated with Ce. More specifically, the YAG - based phosphor can be represented by the composition formula of Y3Al5O 12 :Ce, but the composition of the YAG - based phosphor does not necessarily have to follow stoichiometry.

[0028] Commercially available phosphor particles may be used. Examples of commercially available phosphor particles include Alonbright (registered trademark) from Denka Co., Ltd. Other commercially available products include those from Mitsubishi Chemical Corporation.

[0029] Median diameter of phosphor particles D 50 is preferably 1 μm or more and 20 μm or less, more preferably 5 μm or more and 15 μm or less. 50 By appropriately adjusting the thickness, it becomes easier to form a thin and uniform phosphor sheet.

[0030] It is preferable that the particle size distribution curve of the phosphor particles has two or more maxima. Specifically, it is preferable that maxima are observed in both the particle size range of 1 μm to 6 μm and the particle size range of 10 μm to 25 μm. The presence of two or more maxima means that the phosphor particles contain both large and small particles. Because the small particles penetrate into the "gaps" between the large particles, it is easier to increase the phosphor particle content compared to using only large particles. Furthermore, even if the phosphor particle content is increased, various physical properties are easily maintained. Furthermore, when formed into a coating film, it becomes more difficult for light emitted from the light-emitting element to penetrate.

[0031] Median diameter of phosphor particles D 50 The particle size distribution curve can be adjusted by devising a method for preparing phosphor particles, by appropriately grinding the phosphor particles, or by appropriately mixing two or more phosphor particles with different particle sizes.

[0032] The particle size distribution curve of the phosphor particles can be measured by dispersing the raw material phosphor particles in a dispersion medium using an ultrasonic homogenizer and then measuring it with a laser diffraction / scattering particle size distribution analyzer. From the particle size distribution curve obtained, the median diameter D 50 For details of the dispersion process and the measurement device, see the examples described below. Just to be clear, in this specification, the median diameter D 50 and particle size distribution curves are measured on a volume basis.

[0033] The phosphor sheet of this embodiment may contain only one type of phosphor particles, or may contain two or more types of phosphor particles. The content of phosphor particles in the phosphor sheet is 25 vol% or more and 60 vol% or less, preferably 30 vol% or more and 60 vol% or less, more preferably 35 vol% or more and 60 vol% or less, and even more preferably 40 vol% or more and 50 vol% or less.

[0034] By setting the content of phosphor particles to 25 vol % or more, it becomes easier to sufficiently convert the light emitted from the light emitting element into fluorescence. Another benefit of having a phosphor particle content of 25 vol% or more is that cracks are less likely to occur in the phosphor layer. Based on general knowledge, one of the causes of cracks is thought to be the difference in thermal expansion coefficient between the phosphor layer and the substrate on which the phosphor layer is provided. By having a phosphor particle content of 25 vol% or more, the curable resin component is relatively reduced. This also reduces the difference in thermal expansion coefficient between the phosphor layer and the substrate on which the phosphor layer is provided. As a result, it is thought that cracks are less likely to occur in the phosphor layer.

[0035] The content of phosphor particles in the phosphor sheet is preferably 30 vol% or more, more preferably 35 vol% or more, which makes it possible to sufficiently convert light emitted from the light-emitting element into fluorescence even when the phosphor layer is thin, and to significantly change the color temperature of the light emitted from the light-emitting element.

[0036] On the other hand, the content of phosphor particles in the phosphor sheet is preferably 60 vol % or less. If the content of phosphor particles is not too high, the phosphor particles are less likely to fall off from the formed phosphor layer.

[0037] (curable resin component) The phosphor sheet of this embodiment contains a curable resin component. In this specification, the term "curable resin component" refers not only to (1) a resin (polymer) component that has the property of being cured by the action of heat, light, etc., but also to (2) a component that is a monomer or oligomer before the formation of a coating film, but that can be polymerized by the action of heat, light, etc. to form a resin (polymer) after the formation of a coating film. In relation to the above, in this specification, in addition to polymers, monomers or oligomers, polymerization initiators and curing agents are also considered to be part of the "curable resin component".

[0038] When the curable resin component comprises a resin, a monomer, or an oligomer, it is typically organic, i.e., the curable resin component typically comprises an organic resin, an organic monomer, or an organic oligomer.

[0039] The curable resin component preferably contains a thermosetting resin component, which allows for the production of a highly durable lighting device. Of course, depending on the purpose and application, the curable resin component may also contain a thermoplastic resin.

[0040] The curable resin component preferably contains one or more of silicone resin, epoxy resin, and the like.

[0041] The silicone resin preferably contains a silicone resin having phenyl and / or methyl groups. Such silicone resins are preferred in terms of compatibility with other components, solvent solubility, coatability, heat resistance, durability, etc. The ratio of phenyl groups to methyl groups in this resin is, for example, about 0.3:1 to 1.5:1.

[0042] The hardenable resin component may contain reactive groups, which allow the hardenable resin component to harden by itself. For example, the curable resin component preferably contains a silicone resin containing silanol groups (-Si-OH). This allows a condensation reaction of the silanol groups to occur during coating film formation, resulting in a cured coating film. The silanol content (OH mass%) of the silicone resin containing silanol groups (-Si-OH) is, for example, 0.1 mass% to 5 mass%. As another example, the curable resin component may be one that cures through a hydrosilylation reaction between a vinyl group-containing polymer and a Si—H group-containing silicone polymer (addition reaction type).

[0043] The epoxy resin may be any resin having an epoxy group in the molecule, and examples thereof include bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, alicyclic epoxy resins, linear aliphatic epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, bisphenol A novolac epoxy resins, diglycidyl ethers of biphenols, diglycidyl ethers of naphthalenediol, diglycidyl ethers of phenols, diglycidyl ethers of alcohols, and alkyl-substituted, halide, and hydrogenated versions of these.

[0044] When an epoxy resin is used, it is preferable to use a curing agent capable of curing the epoxy resin, such as polyfunctional phenols, amines, imidazole compounds, acid anhydrides, organic phosphorus compounds, and halides thereof. Examples of polyfunctional phenols include monocyclic bifunctional phenols such as hydroquinone, resorcinol, and catechol, polycyclic bifunctional phenols such as bisphenol A, bisphenol F, naphthalenediols, and biphenols, as well as their halides and alkyl group-substituted derivatives. Furthermore, there are novolaks and resols, which are polycondensates of these phenols with aldehydes. Examples of amines include aliphatic or aromatic primary amines, secondary amines, tertiary amines, quaternary ammonium salts, aliphatic cyclic amines, guanidines, urea derivatives, etc. Examples of these compounds include N,N-benzyldimethylamine, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, tetramethylguanidine, triethanolamine, N,N'-dimethylpiperazine, 1,4-diazabicyclo[2,2,2]octane, 1,8-diazabicyclo[5,4,0]-7-undecene, 1,5-diazabicyclo[4,4,0]-5-nonene, hexamethylenetetramine, pyridine, picoline, piperidine, pyrrolidine, dimethylcyclohexylamine, Examples include dimethylhexylamine, cyclohexylamine, diisobutylamine, di-n-butylamine, diphenylamine, N-methylaniline, tri-n-propylamine, tri-n-octylamine, tri-n-butylamine, triphenylamine, tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium iodide, triethylenetetramine, diaminodiphenylmethane, diaminodiphenyl ether, dicyandiamide, tolylbiguanide, guanylurea, and dimethylurea. Examples of imidazole compounds include imidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole, 2-heptadecylimidazole, 4,5-diphenylimidazole, 2-methylimidazoline, 2-phenylimidazoline, 2-undecylimidazol- ine, 2-heptadecylimidazol- ine, 2-isopropylimidazole, 2,4-dimethylimidazole, 2-phenyl-4-methylimidazole, 2-ethylimidazoline, 2-phenyl-4-methylimidazoline, benzimidazole, and 1-cyanoethylimidazole. Examples of acid anhydrides include phthalic anhydride, hexahydrophthalic anhydride, pyromellitic dianhydride, and benzophenonetetracarboxylic dianhydride. The organic phosphorus compound can be any phosphorus compound having an organic group, without any particular limitation, such as hexamethylphosphoric triamide, tri(dichloropropyl)phosphate, tri(chloropropyl)phosphate, triphenylphosphite, trimethylphosphate, phenylphosphonic acid, triphenylphosphine, tri-n-butylphosphine, and diphenylphosphine.

[0045] The epoxy resin curing agent can be used alone or in combination. The amount of the epoxy resin curing agent used is not particularly limited as long as it can appropriately proceed with the curing reaction of the epoxy group. It is preferably used in the range of 0.01 to 5.0 equivalents, particularly preferably 0.8 to 1.2 equivalents, per mole of epoxy group.

[0046] The phosphor sheet of this embodiment may contain a curing accelerator as needed. Typical curing accelerators include, but are not limited to, tertiary amines, imidazoles, and quaternary ammonium salts.

[0047] (Other ingredients) The phosphor sheet of the embodiment may contain fibers from the viewpoint of handling properties, shape retention, etc. In other words, the phosphor sheet of the embodiment may be in a B-stage state in which the above-mentioned curable resin component or the like is impregnated into the fiber base material. The fiber substrate is not particularly limited, and may be any of those commonly used as prepreg substrates, such as glass cloth, aramid nonwoven fabric, and liquid crystal polymer nonwoven fabric.

[0048] A specific example of glass cloth is Asahi Schwebel's "Style 1027MS" (warp density 75 / 25 mm, weft density 75 / 25 mm, cloth weight 20 g / m 2 , thickness 19μm), Asahi Schwebel "Style 1037MS" (warp density 70 / 25mm, weft density 73 / 25mm, fabric weight 24g / m 2, thickness 28μm), "1078" manufactured by Arisawa Seisakusho (warp density 54 / 25mm, weft density 54 / 25mm, fabric weight 48g / m 2 , thickness 43 μm), "1037NS" manufactured by Arisawa Seisakusho Co., Ltd. (warp density 72 / 25 mm, weft density 69 / 25 mm, fabric weight 23 g / m 2 , thickness 21 μm), "1027NS" manufactured by Arisawa Seisakusho Co., Ltd. (warp density 75 / 25 mm, weft density 75 / 25 mm, fabric weight 19.5 g / m 2 , thickness 16μm), "1015NS" manufactured by Arisawa Seisakusho Co., Ltd. (warp density 95 / 25mm, weft density 95 / 25mm, fabric weight 17.5g / m 2 , thickness 15μm), "1000NS" manufactured by Arisawa Seisakusho Co., Ltd. (warp density 85 / 25mm, weft density 85 / 25mm, fabric weight 11g / m 2 , thickness 10 μm). A specific example of a liquid crystal polymer nonwoven fabric is "VECLUS" (basis weight 6 to 15 g / m), which is an aromatic polyester nonwoven fabric made by the melt-blown method, manufactured by Kuraray Co., Ltd. 2 ) and "Vectran".

[0049] The phosphor sheet of this embodiment may also contain a flowability adjuster from the viewpoint of manufacturability. Examples of flow control agents include silica particles such as hydrophobic silica and hydrophilic silica, and aluminum oxide. Fumed silica is particularly preferred. Examples of commercially available flow control agents include AEROSIL 130, AEROSIL 200, AEROSIL 300, AEROSIL R-972, AEROSIL R-812, AEROSIL R-812S, Aluminum Oxide C (manufactured by Nippon Aerosil Co., Ltd., AEROSIL is a registered trademark), and Carplex FPS-1 (manufactured by DSL, product name).

[0050] (Through hole) The phosphor sheet of this embodiment preferably has through holes for electrically connecting the light emitting elements and copper wiring in the manufacture of a lighting device, which will be described later. The position, size, shape, number, etc. of the through holes may be determined appropriately depending on the design of the lighting device that is ultimately to be obtained. The through holes can be formed by punching, for example, although the through holes may of course be formed by other methods.

[0051] (Method of manufacturing phosphor sheet) The phosphor sheet of this embodiment can be produced based on known knowledge regarding curable resin compositions. As an example, the phosphor sheet of this embodiment can be manufactured by imitating the manufacturing method of "prepreg" used in the manufacture of electrical and electronic components. For example, the phosphor sheet of this embodiment can be manufactured by the following steps: (1) first, dissolving or dispersing components other than the fiber substrate in an organic solvent to produce a varnish, (2) impregnating the fiber substrate with the varnish, and (3) heating the varnish at a temperature and for a time period that does not completely cure the varnish (leading to a B-stage state). Of course, other methods (e.g., a hot-melt method that does not use a solvent) may also be used. The method for manufacturing the prepreg is described in various known documents, which can be used as reference when manufacturing the phosphor sheet of this embodiment. The method for manufacturing the prepreg is described in, for example, JP 2020-139164 A and JP 2004-188652 A.

[0052] <Lighting equipment> The lighting device of this embodiment is (i) an insulating substrate; (ii) a fluorescent layer formed on one side of the insulating substrate, the fluorescent layer being a cured product of the phosphor sheet; (iii) a light-emitting element disposed on a surface of the fluorescent layer opposite to the insulating substrate; Equipped with.

[0053] Preferably, the lighting device of the present embodiment further comprises a white layer between the insulating substrate and the fluorescent layer.

[0054] The lighting device of this embodiment can be manufactured, for example, by the procedure shown in FIGS.

[0055] Figure 1 First, a substrate including at least an insulating substrate 20 as shown in FIG. 1 is prepared. A first copper foil 22A is usually provided on one surface of the insulating substrate 20. A portion of the first copper foil 22A is removed by etching to function as a copper circuit (copper wiring). A second copper foil 22B may be provided on the other surface of the insulating substrate 20.

[0056] The material of the insulating substrate 20 is not particularly limited as long as it is known to be used for PWBs (printed wiring boards). For example, polyimide resin, silicone resin, (meth)acrylic resin, urea resin, epoxy resin, fluororesin, glass, metal (aluminum, copper, iron, stainless steel, etc.) can be used. From the viewpoint of heat resistance, polyimide resin, silicone resin, glass, or metal (such as a so-called "metal substrate" using aluminum or copper as the base metal and provided with an insulating layer) can be preferably used. It is also preferable to use a commercially available material known as a "bonding sheet" or the like. The thickness of insulating substrate 20 is not particularly limited as long as it is within a range that allows it to be used in lighting fixtures, for example, 50 μm or more and 1000 μm or less, specifically 50 μm or more and 500 μm or less.

[0057] As will be described later, the first copper foil 22A is electrically connected to the surface-mounted LED element 28 by solder 30. Electricity is supplied to the surface-mounted LED element 28 by the first copper foil 22A and the solder 30, causing the surface-mounted LED element 28 to emit light. By providing the first copper foil 22A on one side of the insulating substrate 20 and the second copper foil 22B on the other side, a balance of forces is achieved on both sides of the insulating substrate 20, which may prevent warping, for example.

[0058] Figure 2 Preferably, a white layer 24 is provided on the side of the first copper foil 22A of the substrate shown in FIG. 1. The white layer 24 can be provided using, for example, a "white sheet" in a B-stage state, which is manufactured by using white particles (typically white pigments such as titanium oxide or alumina) instead of phosphor particles in the above-mentioned <phosphor sheet>. The white sheet preferably has through holes for electrically connecting the light-emitting element and the copper wiring. Specific conditions for providing the white layer 24 can be the same as those for forming the phosphor layer, which will be described later. The thickness of the white layer 24 is usually 20 to 150 μm, preferably 30 to 120 μm, and more preferably 35 to 100 μm. In particular, when the white sheet has through holes, the thickness of the white layer 24 is preferably 20 to 100 μm, and the total thickness of the white layer 24 and the fluorescent layer 26 described below is more preferably 100 μm or less. Furthermore, if the white sheet has through holes, it is preferable to use appropriate means to make the positions of the through holes coincide with the portions of the first copper foil 22A to be soldered.

[0059] Figure 3 A fluorescent layer 26 is provided on the exposed surface of the white layer 24 (or on the exposed surface of the first copper foil 22A when the white layer 24 is not provided). The fluorescent layer 26 can be provided using the above-mentioned phosphor sheet. 3, the phosphor layer 26 has openings (through holes) for electrically connecting the light-emitting elements and copper wiring in a process described later. When the phosphor sheet has through holes, it is preferable to use an appropriate means to align the positions of the openings (through holes) with the portions of the first copper foil 22A to be soldered.

[0060] For example, the above-mentioned phosphor sheet can be laminated on the exposed surface of the white layer 24 by vacuum lamination. The conditions for the vacuum lamination are not particularly limited, but the thermocompression temperature is preferably 60 to 160°C, more preferably 80 to 140°C. The thermocompression pressure is preferably 0.098 to 1.77 MPa, more preferably 0.29 to 1.47 MPa. The thermocompression time is preferably 20 to 400 seconds, more preferably 30 to 300 seconds. The lamination is preferably carried out under reduced pressure conditions of 26.7 hPa or less.

[0061] After vacuum lamination, the phosphor sheet may be subjected to a smoothing treatment by applying a pressure to the phosphor sheet.

[0062] The phosphor sheet laminated on the exposed surface of the white layer 24, and optionally smoothed, is then heated. This cures the uncured components in the phosphor sheet, providing the phosphor layer 26. The heating conditions are not particularly limited, but the curing temperature can be, for example, 120 to 240°C, preferably 150 to 220°C, and more preferably 170 to 200°C, and the curing time can be, for example, 5 to 120 minutes, preferably 10 to 100 minutes, and more preferably 15 to 90 minutes.

[0063] The above-described method for forming the fluorescent layer 26 is merely an example. The fluorescent layer 26 may be formed by referring to a known prepreg lamination and curing method other than the above.

[0064] Figures 4 and 5 Solder 30 is placed in the openings (through holes) of the phosphor layer 26. Then, the surface-mount LED elements 28 are placed on the solder 30. The solder is then melted by, for example, a reflow method, to solder and electrically connect the surface-mount LED elements 28 and the first copper foil 22A. The specific soldering method and conditions are not particularly limited. Incidentally, the solder 30 may be applied to the first copper foil 22A in advance.

[0065] In this manner, the lighting device can be manufactured. Incidentally, as shown in FIG. 5, a lighting device may be provided with a plurality of light emitting elements (surface-mounted LED elements 28).

[0066] ·supplement In the step of providing the white layer 24 or the step of providing the fluorescent layer 26, a spacer (shim) may be used for the purpose of adjusting the film thickness, etc. That is, the white layer 24 or the fluorescent layer 26 may be provided by using a spacer and then applying heat, pressure, or the like.

[0067] 3 and 4, depending on the material of the resin sheet and the process conditions, when the sheet in the B-stage state is heated, the softened resin component may "flow out" to the portion of the first copper foil 22A that is to be soldered to the surface-mount LED element 28. If this occurs, there is a possibility that the first copper foil 22A and the surface-mount LED element 28 will not be electrically connected. One way to prevent this is to change the resin sheet material or process conditions. Another method is to temporarily "protect" the portion of the first copper foil 22A to which the surface-mount LED element 28 is to be soldered by using an appropriate member, such as a spring pin. Yet another method is to apply solder 30 to the first copper foil 22A in advance, as described above, which, in principle, can prevent the softened resin component from "flowing out" to the portion of the first copper foil 22A to which the surface-mount LED element 28 is to be soldered.

[0068] Surface-mounted LED element 28 In this embodiment, it is preferable that the light-emitting element (surface-mounted LED element 28) does not have a reflector. Specifically, some known surface-mounted LED elements (light-emitting elements) are equipped with a reflector, as shown in FIG. 6A, so that light does not leak sideways or downward. However, in this embodiment, it is preferable that the light-emitting element (surface-mounted LED element 28) does not have a reflector, as shown in FIG. 6B. By using a light-emitting element without a reflector, light from the LED chip leaks sideways and downwards. This leaked light then hits the portion of the fluorescent layer 26 indicated by α, causing that portion to emit light. This further reduces the problems of glare and multiple shadows.

[0069] 6A, a semiconductor light emitting element 100 is disposed in a package 108 formed by a substrate 102 and a reflector (housing) 104, and a sealing member 110 (light-transmitting resin) is filled in the package 108. The substrate 102 may be provided with wiring 112. In Figure 6B, the same elements as in Figure 2A are assigned the same reference numerals. The light-emitting device in Figure 2B does not use a housing (reflector). After mounting the semiconductor light-emitting device 100 as shown in the figure, the sealing member 110 can be formed by molding using a desired mold. Alternatively, the sealing member 110 may be prepared in advance in a desired shape, and then adhered to the substrate 102 so as to cover the semiconductor light-emitting device 100.

[0070] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. [Example]

[0071] The embodiments of the present invention will be described in detail based on Examples and Comparative Examples. However, it should be noted that the present invention is not limited to the Examples.

[0072] <Preparation of phosphor particles> CASN-1: CASN phosphor manufactured by Denka, product number RE-650YMDB, D 50 =15.7μm CASN-2: CASN phosphor manufactured by Denka, product number RE-Sample 650SD4, D 50 =3.2μm

[0073] <Production of phosphor sheets using silicone resin> In addition to the above phosphor particles, the following materials were prepared. Curable resin component: Toray Dow Corning silicone resin "RSN-0805" (silanol group-containing, silanol content (OH mass) 1%, silicon dioxide content 48% by mass, phenyl:methyl ratio = 1.1:1, weight average molecular weight 200-300 x 10 3 , xylene included, resin solids 50% by weight Flow modifier: AEROSIL 200 fumed silica from Nippon Aerosil Co., Ltd. Solvent: Butyl carbitol

[0074] Among the components listed in Table 1, first, the curable resin component (silicone resin) and a solvent were mixed to obtain a uniform solution. Thereafter, phosphor particles and a flowability modifier (only in Example 3) were added to the solution, and mixed and dispersed uniformly to obtain silicone resin varnishes 1-1 to 1-4.

[0075] [Table 1]

[0076] The silicone resin varnish was impregnated into a commercially available fiber substrate (glass cloth) and dried in a vertical drying oven. After cooling, through-holes for connecting the light-emitting element to the copper wiring were formed by punching. In this way, silicone resin-based phosphor sheets 2-1 to 2-4 were produced. The drying conditions (temperature and time) were adjusted so that the silicone resin phosphor sheet would reach a B-stage state. In addition, a fiber substrate (glass cloth) with an appropriate thickness was selected, taking into account the thickness (50 μm) of the phosphor layer described below.

[0077] <Manufacturing phosphor sheets using epoxy resin> First, epoxy resin varnishes 2-1 to 2-4 having the following compositions were prepared. Bisphenol A epoxy resin 640 parts by mass Bisphenol A novolac resin 25 parts by mass Ethylmethylimidazole 0.2 parts by weight Phosphor particles: Amount shown in the table below Methyl ethyl ketone solvent: Resin varnish viscosity is approximately 0.1 Ns / m 2 The quantity that becomes

[0078] [Table 2]

[0079] The epoxy resin varnish was impregnated into a commercially available fiber substrate (glass cloth) and dried in a vertical drying oven at 135°C for 5 minutes. After cooling, through-holes for connecting the light-emitting element to the copper wiring were punched out. In this way, B-stage epoxy resin phosphor sheets 2-1 to 2-4 were produced. Incidentally, taking into consideration the thickness (50 μm) of the phosphor layer described below, a fiber substrate (glass cloth) with an appropriate thickness was selected.

[0080] <Production of white sheets> A silicone resin-based white sheet was manufactured in the same manner as described above in <Manufacturing of phosphor sheet using silicone resin>, except that titanium oxide / alumina mixed particles were used instead of phosphor particles so that the amount in the non-volatile components was 50 vol% and the thickness of the glass cloth was changed appropriately. In addition, an epoxy resin-based white sheet was manufactured in the same manner as described above in <Manufacturing of phosphor sheet using epoxy resin>, except that titanium oxide / alumina mixed particles were used instead of phosphor particles so that the amount in the non-volatile components was 50 vol% and the thickness of the glass cloth was changed appropriately.

[0081] <Production of lighting device (silicone-based)> Using the above phosphor sheet, a lighting device was fabricated in which multiple CSPs were aligned at regular intervals on the phosphor layer. The manufacturing procedure is briefly described below. (1) As the insulating substrate material, we prepared a bonding sheet CS-3305A manufactured by Risho Kogyo Co., Ltd., with copper foil attached on both sides. We etched the copper foil to form a copper circuit on the first copper foil. (2) Place the above silicone resin white sheet on the first copper foil and apply pressure of 20 kgf / cm 2 The mixture was pressed at a pressure of 1000 kJ / cm at a temperature of 190° C. for 90 minutes, thereby forming a white layer having a thickness of 35 μm. (3) Place the above silicone resin phosphor sheet (any of 1-1 to 1-4) on the white layer and apply pressure of 20 kgf / cm 2 The mixture was pressed at a pressure of 100 psi at a temperature of 190° C. for 90 minutes, thereby forming a phosphor layer with a thickness of 50 μm. (4) A commercially available CSP (WICOP SZ8-Y15-WW-C8, manufactured by Seoul Semiconductor, reflector-less, color temperature 2200-2300K), which is a surface-mount LED element, was electrically connected to the first copper foil (copper circuit) by soldering.

[0082] In the above (2) and (3), the positions of the through holes in each sheet were set to be the positions where the CSP and the first copper foil were connected in (4).

[0083] <Production of lighting device (epoxy type)> Using the above phosphor sheet, a lighting device was fabricated in which multiple CSPs were aligned at regular intervals on the phosphor layer. The manufacturing procedure is briefly described below. (1) As the insulating substrate material, we prepared a bonding sheet CS-3305A manufactured by Risho Kogyo Co., Ltd., with copper foil attached on both sides. We etched the copper foil to form a copper circuit on the first copper foil. (2) Place the above white epoxy resin sheet on the first copper foil and apply pressure of 20 kgf / cm 2 The mixture was pressed at a pressure of 1000 kJ / cm at a temperature of 190° C. for 90 minutes, thereby forming a white layer having a thickness of 35 μm. (3) Place the above-mentioned epoxy resin phosphor sheet (any of 2-1 to 2-4) on the white layer and apply pressure of 20 kgf / cm 2 The mixture was pressed at a pressure of 100 psi at a temperature of 190° C. for 90 minutes, thereby forming a phosphor layer with a thickness of 50 μm. (4) A commercially available CSP (WICOP SZ8-Y15-WW-C8, manufactured by Seoul Semiconductor, reflector-less, color temperature 2200-2300K), which is a surface-mount LED element, was electrically connected to the first copper foil (copper circuit) by soldering.

[0084] In the above (2) and (3), the positions of the through holes in each sheet were set to be the positions where the CSP and the first copper foil were connected in (4).

[0085] <Evaluation: Color temperature conversion> An electric current was passed through each of the lighting devices fabricated above, causing the lighting device to emit light. The color temperature of the light emitted from the lighting device was measured using a total luminous flux measurement system (equipped with an integrating sphere) manufactured by Otsuka Electronics Co., Ltd. The color temperature conversion ability was evaluated as "good" when the measured color temperature was 2000 to 2100 K, and the color temperature was converted by at least 100 K from the color temperature of the CSP itself (2200 to 2300 K).

[0086] As a result, the color temperature conversion performance of all the lighting devices created was "good."

[0087] As described above, by using a phosphor "sheet" in a B-stage state, it was possible to form a phosphor layer using a simple process without using paint, and to manufacture a lighting device.

[0088] This application claims priority based on Japanese Patent Application No. 2022-049903, filed on March 25, 2022, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0089] 20 Insulating substrate 22A Copper foil 22B Cupric foil 24 White layer 26 Fluorescent Layer 28 Surface-mounted LED elements 30 solder 100 Semiconductor light emitting element 102 Circuit Board 104 Reflector (housing) 108 Package 110 Sealing member 112 Wiring

Claims

1. A phosphor sheet comprising a thermosetting resin composition in the B-stage state, containing phosphor particles and a curable resin component, having a thickness of 20 to 150 μm, and existing in a state not adhered to a substrate, Having a through hole, A phosphor sheet in which the median diameter D 50 of the phosphor particles is 1 μm or more and 20 μm or less.

2. A phosphor sheet comprising a thermosetting resin composition in a B-stage state, comprising phosphor particles and a curable resin component, having a thickness of 20 to 150 μm, and existing in a state not adhered to a substrate, A phosphor sheet in which two or more maxima are observed in the particle size distribution curve of the phosphor particles.

3. A phosphor sheet according to claim 1 or 2, A phosphor sheet comprising at least one curable resin component selected from the group consisting of epoxy resins and silicone resins.

4. A phosphor sheet according to claim 2, A phosphor sheet with through-holes.

5. A phosphor sheet according to claim 1 or 2, A phosphor sheet having a phosphor particle content of 25 vol% to 60 vol%.

6. A phosphor sheet according to claim 1 or 2, The phosphor sheet includes phosphor particles capable of converting blue light into light with a wavelength longer than the wavelength of the blue light.

7. A phosphor sheet according to claim 2, Median diameter D of the aforementioned phosphor particles ５０ A phosphor sheet having a thickness of 1 μm or more and 20 μm or less.

8. A phosphor sheet according to claim 1, A phosphor sheet in which two or more maxima are observed in the particle size distribution curve of the phosphor particles.

9. A phosphor sheet according to claim 1 or 2, A phosphor sheet in which a maximum is observed in both the region of particle size between 1 μm and 6 μm and the region of particle size between 10 μm and 25 μm in the particle size distribution curve of the phosphor particles.

10. A phosphor sheet according to claim 1 or 2, The phosphor particles include one or more selected from the group consisting of CASN-based phosphors, SCASN-based phosphors, La ３ Si ６ N １１ -based phosphors, Sr ２ Si ５ N ８ -based phosphors, Ba ２ Si ５ N ８ -based phosphors, α-sialon-based phosphors, β-sialon-based phosphors, LuAG-based phosphors, and YAG-based phosphors, and a phosphor sheet containing the same.

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