WO2023182379A1

WO2023182379A1 - Phosphor sheet and lighting device

Info

Publication number: WO2023182379A1
Application number: PCT/JP2023/011316
Authority: WO
Inventors: 正宏小西
Original assignee: デンカ株式会社
Priority date: 2022-03-25
Filing date: 2023-03-22
Publication date: 2023-09-28
Also published as: TW202407079A

Abstract

Provided is a phosphor sheet comprising a thermosetting resin composition that contains phosphor particles and a curing resin component and is in a B stage state, and having a thickness of 20-150 μm. Also provided is a lighting device equipped with a phosphor layer that is a cured product of the phosphor sheet, and a light-emitting element installed on a surface on the reverse side from an insulating substrate of the phosphor layer.

Description

Phosphor sheets and lighting devices

The present invention relates to a phosphor sheet and a lighting device.

Various developments are underway regarding lighting devices using LEDs (Light Emitting Devices). In addition to the development of LEDs themselves, the development of mounting boards equipped with LEDs is also known.

For example, in Example 2 of Patent Document 1, (i) a glass binder paint containing 30 vol% of phosphor was applied to the surface of a glass substrate to form a phosphor layer with a thickness of 200 μm; (ii) ) A mounting board for LED lighting was obtained by bonding multiple CSPs on the glass substrate; and (iii) when electricity was applied to the mounting board, there was no glare or glare even though the multiple CSPs were emitting light. It states that the problem of multiple shadows has been reduced.
(CSP is an abbreviation for Chip Scale Package or Chip Size Package, which is an LED chip wrapped in phosphor resin, making it packageless with only the LED chip and phosphor resin.)

International Publication No. 2019/093339

In Example 2 of Patent Document 1, a phosphor layer with a thickness of 200 μm is formed on a glass substrate using a “glass binder paint” containing a phosphor. However, in order to fully cure glass binder paints, a sintering process at high temperatures is usually required. Therefore, with respect to Example 2 of Patent Document 1, there is room for improvement in terms of ease of providing the phosphor layer, etc. Additionally, the casing/substrate to which the glass binder paint is applied is subject to restrictions such as heat resistance and optimization of expansion coefficient. Furthermore, forming a phosphor layer using "paint" has problems, such as the complexity of the process and the need to solve the problem of "dripping" of the paint.

The present invention has been made in view of these circumstances. One of the objects of the present invention is to provide a material on which a phosphor layer can be formed by a simple process without using paint.

As a result of intensive studies, the present inventors completed the invention provided below and solved the above problems.

1.
A phosphor sheet comprising a thermosetting resin composition in a B-stage state, including phosphor particles and a curable resin component, and having a thickness of 20 to 150 μm.
2.
1. The phosphor sheet described in
A phosphor sheet in which the curable resin component includes at least one selected from the group consisting of epoxy resins and silicone resins.
3.
1. or 2. The phosphor sheet described in
A phosphor sheet with through holes.
4.
1. ~3. The phosphor sheet according to any one of
A phosphor sheet having a content of phosphor particles of 25 vol% or more and 60 vol% or less.
5.
1. ~4. The phosphor sheet according to any one of
The phosphor particles include phosphor particles that can convert blue light into light with a wavelength longer than the wavelength of the blue light.
6.
1. ~5. The phosphor sheet according to any one of
A phosphor sheet in which the median diameter _D50 of the phosphor particles is 1 μm or more and 20 μm or less.
7.
1. ~6. The phosphor sheet according to any one of
A phosphor sheet in which two or more maxima are observed in the particle size distribution curve of the phosphor particles.
8.
1. ~7. The phosphor sheet according to any one of
In the particle size distribution curve of the phosphor particles, a maximum is observed 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.
1. ~8. The phosphor sheet according to any one of
The phosphor particles include a CASN-based phosphor, a SCASN-based phosphor, a La ₃ Si ₆ N ₁₁ -based phosphor, a Sr ₂ Si ₅ N ₈ -based phosphor, a Ba ₂ Si ₅ N ₈ -based phosphor, and an α-sialon-based phosphor. A phosphor sheet containing one or more selected from the group consisting of a phosphor, a β-sialon phosphor, a LuAG phosphor, and a YAG phosphor.
10.
an insulating substrate;
1. provided on one side of the insulating substrate; ~9. a phosphor layer that is a cured product of the phosphor sheet according to any one of
A lighting device comprising: a light emitting element installed on a surface of the fluorescent layer opposite to the insulating substrate.
11.
10. The lighting device according to
The lighting device further includes a white layer between the insulating substrate and the fluorescent layer.
12.
10. or 11. The lighting device according to
A lighting device in which a plurality of the light emitting elements are installed.
13.
10. ~12. The lighting device according to any one of
A lighting device in which the light emitting element does not include a reflector.

According to the present invention, a phosphor layer can be formed by a simple process without using paint.

It is a figure for explaining the manufacturing procedure of a lighting device. It is a figure for explaining the manufacturing procedure of a lighting device. It is a figure for explaining the manufacturing procedure of a lighting device. It is a figure for explaining the manufacturing procedure of a lighting device. It is a figure for explaining the manufacturing procedure of a lighting device, and a lighting device. FIG. 3 is a diagram for explaining an LED chip with a reflector and an LED chip without a reflector.

Embodiments of the present invention will be described in detail below with reference to the drawings.
In all the drawings, similar components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.
To avoid complication, (i) if there are multiple identical components in the same drawing, only one of them will be given a reference numeral and not all of them, or (ii) especially 2 and subsequent parts, components similar to those in FIG. 1 may not be labeled again.
All drawings are for illustrative purposes only. The shapes and dimensional ratios of each member in the drawings do not necessarily correspond to the actual product.

In the present specification, the notation "X to Y" in the description of numerical ranges indicates from X to Y, unless otherwise specified. For example, "1 to 5% by mass" means "1 to 5% by mass".

In the description of a group (atomic group) in this specification, a description that does not indicate whether it is substituted or unsubstituted includes both those without a substituent and those with a substituent. For example, the term "alkyl group" includes not only an alkyl group without a substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).
In this specification, the expression "(meth)acrylic" represents a concept that includes both acrylic and methacrylic. The same applies to similar expressions such as "(meth)acrylate".
The term "organic group" as used herein means an atomic group obtained by removing one or more hydrogen atoms from an organic compound, unless otherwise specified. For example, a "monovalent organic group" refers to an atomic group obtained by removing one hydrogen atom from an arbitrary organic compound.

<Phosphor sheet>
The phosphor sheet of this embodiment includes phosphor particles and a curable resin component, and is composed of a thermosetting resin composition in a B-stage state.
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.

Since the phosphor sheet of this embodiment is in a B-stage state (in other words, a semi-cured state), its fluidity at a temperature around room temperature has substantially disappeared, and it is in the form of a "sheet". can be kept.
Since the phosphor sheet of this embodiment is in a B-stage state, it can be placed on a substrate as a sheet and then heated (preferably heated while applying pressure) to adhere sufficiently strongly to the substrate. , a phosphor layer can be provided. At this time, since there is no need to apply liquid paint, the phosphor layer can be formed using a simpler process than in the past. Incidentally, in this specification, the B-stage state includes a state before the C-stage state, that is, before complete curing.
Since the thickness of the phosphor sheet of this embodiment is 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. Moreover, since the thickness of the phosphor sheet of this embodiment is 150 μm or less, the time required for thermosetting can be shortened. It is also preferable that the phosphor sheet is not too thick because it facilitates electrical connection (soldering, etc.) between the light emitting element and the copper wiring in manufacturing the lighting device described later.

Hereinafter, the phosphor sheet of this embodiment will be explained in more detail.

(phosphor particles)
The phosphor particles included in the phosphor sheet of this embodiment may be any phosphor particles that emit fluorescence when exposed to light emitted from a light emitting element. Specifically, the phosphor particles need only be able to convert blue light into light with a longer wavelength than the wavelength of the blue light. Only one type of particles may be used, or two or more phosphor particles may be used in combination.

Examples of the phosphor particles include 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, and α-sialon phosphors. Examples include one or more selected from the group consisting of phosphors, β-sialon phosphors, LuAG phosphors, and YAG phosphors. These phosphors usually contain activating elements such as Eu and Ce.

The CASN-based phosphor (a type of nitride phosphor) preferably contains Eu. The CASN-based phosphor is, for example, a red phosphor represented by the formula CaAlSiN ₃ :Eu ²⁺ , which uses Eu ²⁺ as an activator and has a crystal made of alkaline earth silicon nitride as a matrix.
The definition of Eu-containing CASN-based phosphors in this specification excludes Eu-containing SCASN-based phosphors.

The SCASN-based phosphor (a type of nitride phosphor) preferably contains Eu. The SCASN-based phosphor is, for example, a red phosphor represented by the formula (Sr,Ca)AlSiN ₃ :Eu ²⁺ , which uses Eu ²⁺ as an activator and has a crystal made of alkaline earth silicon nitride as a matrix.

Specifically, the La ₃ Si ₆ N ₁₁ -based phosphor is La ₃ Si ₆ N ₁₁ :Ce phosphor. This typically wavelength converts blue light from a blue LED to yellow light.

Specifically, the Sr ₂ Si ₅ N ₈ -based phosphor includes a Sr ₂ Si ₅ N ₈ :Eu ²⁺ phosphor, a Sr ₂ Si ₅ N ₈ :Ce ³⁺ phosphor, and the like. These typically wavelength convert blue light from blue LEDs into yellow to red light.

Specifically, the Ba ₂ Si ₅ N ₈ -based phosphor is Ba ₂ Si ₅ N ₈ :Eu. This typically wavelength converts blue light from a blue LED to orange-red light.

The α-type sialon-based phosphor preferably contains Eu. α-type sialon containing Eu is represented by, for example, the general formula: M _x Eu _y Si _12-(m+n) Al _(m+n) O _n N _16-n . In the general formula, M is one or more elements containing at least Ca selected from the group consisting of Li, Mg, Ca, Y, and lanthanide elements (excluding La and Ce), and the valence of M is a When, ax+2y=m, x is 0<x≦1.5, 0.3≦m<4.5, and 0<n<2.25.

The β-type sialon-based phosphor preferably contains Eu. 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 derived from β-sialon containing Eu ²⁺ as a solid solution. It is a phosphor. In the general formula, the Z value and the europium content are not particularly limited. The Z value is, for example, greater than 0 and less than or equal to 4.2, and is preferably greater than or equal to 0.005 and less than or equal to 1.0 from the viewpoint of further improving the luminescence intensity of β-sialon. Further, the content of europium is preferably 0.1% by mass or more and 2.0% by mass or less.

LuAG-based phosphor usually means lutetium aluminum garnet crystal. Considering the application to a lighting device, it is preferable that LuAG is a LuAG:Ce phosphor. More specifically, LuAG can be represented by the composition formula Lu ₃ Al ₅ O ₁₂ :Ce, but the composition of LuAG does not necessarily have to follow stoichiometry.

YAG-based phosphor usually means yttrium aluminum garnet crystal. Considering application to lighting devices, it is preferable that the YAG-based phosphor be activated with Ce. More specifically, the YAG-based phosphor can be represented by the composition formula Y ₃ Al ₅ O ₁₂ :Ce, but the composition of the YAG-based phosphor does not necessarily have to follow stoichiometry.

Commercially available products may be used as the phosphor particles. Examples of commercially available phosphor particles include Aron Bright (registered trademark) manufactured by Denka Corporation. It is also commercially available from Mitsubishi Chemical and other companies.

The median diameter _D50 of the phosphor particles is preferably 1 μm or more and 20 μm or less, more preferably 5 μm or more and 15 μm or less. By appropriately adjusting the median diameter _D50 , it becomes easier to form a thin and uniform phosphor sheet.

It is preferable that two or more maxima are observed in the particle size distribution curve of the phosphor particles. Specifically, it is preferable that the maximum is observed in both a region of particle size of 1 μm or more and 6 μm or less and a region of particle size of 10 μm or more and 25 μm or less. The fact that two or more local maxima are observed means that the phosphor particles include both large particles and small particles. Since the small particles fit into the "gaps" between the large particles, it is easier to increase the content of phosphor particles compared to when only large particles are used. Moreover, even if the content of phosphor particles is increased, various physical properties can be easily maintained. Furthermore, when formed into a coating film, it becomes more difficult for light emitted from the light emitting element to pass through.

The median diameter _D50 and particle size distribution curve of the phosphor particles can be determined by improving the preparation method of the phosphor particles, appropriately crushing the phosphor particles, and appropriately mixing two or more phosphor particles with different particle sizes. It can be adjusted by

The particle size distribution curve of the phosphor particles can be measured using a laser diffraction scattering particle size distribution measuring device after dispersing raw material phosphor particles in a dispersion medium using an ultrasonic homogenizer. Then, the median diameter _D50 can be determined from the obtained particle size distribution curve. For details of the distributed processing and the measuring device, please refer to Examples described later.
As a reminder, in this specification, the median diameter _D50 and the particle size distribution curve are measured on a volume basis.

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 the phosphor particles in the phosphor sheet is 25 vol% or more and 60 vol% or less. This content is preferably 30 vol% or more and 60 vol% or less, more preferably 35 vol% or more and 60 vol% or less, and still more preferably 40 vol% or more and 50 vol% or less.

By setting the content of the phosphor particles to 25 vol % or more, it becomes easy to sufficiently convert the light emitted from the light emitting element into fluorescence.
Further, by setting the content of the phosphor particles to 25 vol % or more, there is also the advantage that cracks are less likely to occur in the phosphor layer. Based on general knowledge, one of the causes of crack generation is considered to be the difference in thermal expansion coefficient between the phosphor layer and the substrate on which the phosphor layer is provided. By setting the content of the phosphor particles to 25 vol% or more, the amount of the curable resin component is relatively reduced. Then, the difference between the coefficient of thermal expansion of the phosphor layer and the coefficient of thermal expansion of the substrate on which the phosphor layer is provided becomes small. As a result, it is thought that cracks are less likely to occur in the phosphor layer.

The content of phosphor particles in the phosphor sheet is preferably 30 vol% or more, more preferably 35 vol% or more. By doing this, for example, even if the phosphor layer is thin, the light emitted from the light emitting element can be sufficiently converted into fluorescence, and the color temperature of the light emitted from the light emitting element can be significantly changed. do.

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

(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 (2) a monomer or oligomer component before coating film formation. However, it also includes components that can be increased in molecular weight to form resins (polymers) by the action of heat, light, etc. after coating film formation.
In connection with the above, in this specification, in addition to polymers, monomers, or oligomers, polymerization initiators, curing agents, and the like are also considered to be part of the "curable resin component."

When the curable resin component includes resins, monomers or oligomers, these are usually organic. That is, the curable resin component usually contains an organic resin, an organic monomer, or an organic oligomer.

The curable resin component preferably includes a thermosetting resin component. Thereby, a highly durable lighting device can be manufactured. Of course, depending on the purpose and use, the curable resin component may include a thermoplastic resin.

The curable resin component preferably contains one or more of silicone resins, epoxy resins, etc.

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

The curable resin component can include reactive groups. This allows the curable resin component to cure itself.
As an example, the curable resin component preferably includes a silicone resin containing a silanol group (-Si-OH). As a result, a condensation reaction of silanol groups occurs during coating film formation, and a cured coating film is obtained. The silanol content (OH mass %) of the silicone resin containing a silanol group (-Si-OH) is, for example, 0.1 mass % or more and 5 mass % or less.
As another example, the curable resin component may be one that is cured by a hydrosilylation reaction between a vinyl group-containing polymer and a Si-H group-containing silicone polymer (addition reaction type).

The epoxy resin may be any resin as long as it has an epoxy group in its molecule. Bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, Examples include diglycidyl etherified products of biphenol, diglycidyl etherified products of naphthalene diol, diglycidyl etherified products of phenols, diglycidyl etherified products of alcohols, alkyl substituted products, halides, hydrogenated products, etc. Can be done.

When using an epoxy resin, it is preferable to use a curing agent that can harden the epoxy resin. Examples of the curing agent include polyfunctional phenols, amines, imidazole compounds, acid anhydrides, organic phosphorus compounds, and halides thereof.
Examples of polyfunctional phenols include monocyclic difunctional phenols such as hydroquinone, resorcinol, and catechol, polycyclic difunctional phenols such as bisphenol A, bisphenol F, naphthalene diols, biphenols, and their halides and alkyl group-substituted phenols. There are bodies, etc. Furthermore, there are novolacs and resols, which are polycondensates of these phenols and aldehydes.
Examples of amines include aliphatic or aromatic primary amines, secondary amines, tertiary amines, quaternary ammonium salts, aliphatic cyclic amines, guanidines, urea derivatives, and the like. 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, 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, Examples include 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-undecylimidazoline, 2-heptadecylimidazoline, 2-isopropylimidazole, 2,4-dimethylimidazole, 2-phenyl-4 - Methylimidazole, 2-ethylimidazoline, 2-phenyl-4-methylimidazoline, benzimidazole, 1-cyanoethylimidazole and the like.
Examples of acid anhydrides include phthalic anhydride, hexahydrophthalic anhydride, pyromellitic dianhydride, benzophenonetetracarboxylic dianhydride, and the like.
As the organic phosphorus compound, any phosphorus compound having an organic group can be used without particular limitation. For example, hexamethylphosphoric acid triamide, tri(dichloropropyl) phosphate, tri(chloropropyl) phosphate, triphenyl phosphite, trimethyl phosphate, phenylphosphonic acid, triphenylphosphine, tri-n-butylphosph These include fins and diphenylphosphine.

Epoxy resin curing agents can be used alone or in combination. The amount of the curing agent for the epoxy resin to be used is not particularly limited as long as the curing reaction of the epoxy group can proceed appropriately. It is preferably used in an amount of 0.01 to 5.0 equivalents, particularly preferably 0.8 to 1.2 equivalents, per mole of epoxy group.

The phosphor sheet of this embodiment may contain a curing accelerator as necessary. Typical curing accelerators include tertiary amines, imidazoles, quaternary ammonium salts, etc., but are not limited thereto.

(Other ingredients)
The phosphor sheet of the embodiment may contain fibers from the viewpoint of handling properties, shape retention properties, and the like. In other words, the phosphor sheet of this embodiment may be in a B-stage state by impregnating the above-mentioned curable resin component into a fiber base material.
The fiber base material is not particularly limited. Commonly used base materials for prepregs, such as glass cloth, aramid nonwoven fabric, and liquid crystal polymer nonwoven fabric, can be used.

Specific examples of glass cloth include "Style 1027MS" manufactured by Asahi Schwebel (warp density 75/25 mm, weft density 75/25 mm, cloth weight 20 g/m ² , thickness 19 μm), "Style 1027MS" manufactured by Asahi Schwebel Style 1037MS" (warp density 70/25mm, weft density 73/25mm, fabric weight 24g/ ^m2 , thickness 28μm), Arisawa Seisakusho's "1078" (warp density 54/25mm, weft density 54 /25mm, cloth weight 48g/ ^m2 , thickness 43μm), "1037NS" manufactured by Arisawa Seisakusho (warp density 72/25mm, weft density 69/25mm, cloth weight 23g/ ^m2 , thickness 21μm), "1027NS" manufactured by Arisawa Seisakusho Co., Ltd. (warp density 75 threads/25 mm, weft density 75 threads/25 mm, fabric weight 19.5 g/m ² , thickness 16 μm), "1015NS" manufactured by Arisawa Seisakusho Co., Ltd. (warp density 95 threads/25 mm) /25mm, weft density 95/25mm, fabric weight 17.5g/ ^m2 , thickness 15μm), "1000NS" manufactured by Arisawa Seisakusho (warp density 85/25mm, weft density 85/25mm, fabric weight 11g) /m ² , thickness 10 μm), etc. Further, specific examples of the liquid crystal polymer nonwoven fabric include "Veklus" (basis weight 6 to 15 g/m ² ) and "Vectran" produced by the melt-blowing aromatic polyester nonwoven fabric manufactured by Kuraray Co., Ltd.

Further, the phosphor sheet of this embodiment may contain a fluidity regulator from the viewpoint of manufacturing suitability.
As the fluidity modifier, silica particles such as hydrophobic silica and hydrophilic silica, aluminum oxide, etc. can be used. In particular, fumed silica is preferably used. Commercially available fluidity modifiers include, for example, 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). ), Carplex FPS -1 (manufactured by DSL, trade name).

(through hole)
The phosphor sheet of this embodiment preferably has through holes. This is for electrically connecting the light emitting element and the copper wiring in manufacturing the lighting device, which will be described later.
The position, size, shape, number, etc. of the through holes may be determined as appropriate depending on the design of the illumination device to be finally obtained.
The through hole can be provided, for example, by punching. Of course, the through holes may be provided in other ways.

(Method for manufacturing phosphor sheet)
The phosphor sheet of this embodiment can be manufactured based on known knowledge regarding curable resin compositions.
As an example, the phosphor sheet of this embodiment can be manufactured by following the manufacturing method of "prepreg" used for manufacturing electrical and electronic parts. As an example, in the phosphor sheet of this embodiment, (1) first, components other than the fiber base material are dissolved or dispersed in an organic solvent to produce a varnish, and (2) the fiber base material is impregnated with the varnish. (3) The varnish can be manufactured by heating at a temperature and for a time that does not completely cure the varnish (becomes in a B-stage state). Of course, other methods (for example, a hot melt method that does not use a solvent) may be used.
The prepreg manufacturing method is described in various known documents, so it can be used as a reference when manufacturing the phosphor sheet of this embodiment. Methods for manufacturing prepreg are described, for example, in JP-A No. 2020-139164, JP-A No. 2004-188652, and the like.

<Lighting device>
The lighting device of this embodiment is
(i) an insulating substrate;
(ii) a phosphor layer that is a cured product of the phosphor sheet, provided on one side of the insulating substrate;
(iii) a light emitting element installed on the surface of the fluorescent layer opposite to the insulating substrate;
Equipped with

Furthermore, the lighting device of this embodiment preferably further includes a white layer between the insulating substrate and the fluorescent layer.

The lighting device of this embodiment can be manufactured, for example, by the steps shown in FIGS. 1 to 5.

・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 normally provided on one surface of the insulating substrate 20. A part of the first copper foil 22A is removed by etching and functions as a copper circuit (copper wiring). Further, a second copper foil 22B may be provided on the other surface of the insulating substrate 20.

The material of the insulating substrate 20 is not particularly limited as long as it is known to be used for PWBs (printed circuit 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. Preferably, from the viewpoint of heat resistance, polyimide resin, silicone resin, glass, or metal (such as a so-called "metal substrate" in which aluminum or copper is used as a base metal and an insulating layer is provided) can be used. It is also preferable to use a material commercially available under the name of "bonding sheet" or the like.
The thickness of the insulating substrate 20 is not particularly limited as long as it can be used for lighting equipment. For example, it is 50 μm or more and 1000 μm or less, specifically 50 μm or more and 500 μm or less.

The first copper foil 22A is electrically connected to the surface-mounted LED element 28 by solder 30, as described later. Electricity is supplied to the surface-mounted LED element 28 by the cuprous foil 22A and the solder 30, and the surface-mounted LED element 28 emits light.
By having the first copper foil 22A on one side of the insulating substrate 20 and the second copper foil 22B on the other side, the force can be balanced on both sides of the insulating substrate 20, and the occurrence of warping, for example, can be suppressed. There is.

・Figure 2
Preferably, the white layer 24 is provided on the side of the first copper foil 22A of the substrate shown in FIG. The white layer 24 is, for example, a B-stage "phosphor sheet" manufactured by using white particles (typically a white pigment such as titanium oxide or alumina) instead of the phosphor particles in the above-mentioned <phosphor sheet>. It can be provided using a "white sheet". It is preferable that the white sheet has a through hole for electrically connecting the light emitting element and the copper wiring. The specific conditions for providing the white layer 24 can be the same as those for forming the fluorescent 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 it is more preferable that the total thickness of the white layer 24 and the fluorescent layer 26 described below be 100 μm or less. preferable.
Moreover, when the white sheet has a through hole, it is preferable that the position of the through hole coincides with the portion of the first copper foil 22A to be soldered by appropriate means.

・Figure 3
A fluorescent layer 26 is provided on the exposed surface of the white layer 24 (in the case where the white layer 24 is not provided, the exposed surface of the first copper foil 22A). The fluorescent layer 26 can be provided using the above-mentioned phosphor sheet.
Incidentally, in FIG. 3, the fluorescent layer 26 has an opening (through hole) for electrically connecting the light emitting element and the copper wiring in a process described later. When the phosphor sheet has a through hole, it is preferable that the position of the opening (through hole) coincides with the portion of the first copper foil 22A to be soldered by appropriate means.

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

After vacuum lamination, the phosphor sheet may be smoothed by applying a pressing force to the phosphor sheet.

A phosphor sheet laminated on the exposed surface of the white layer 24 and, if necessary, smoothed, is heated. As a result, the uncured components in the phosphor sheet are cured, and the phosphor layer 26 can be provided. The heating conditions here are not particularly limited, but for example, the curing temperature is 120 to 240°C, preferably 150 to 220°C, more preferably 170 to 200°C, and the curing time is 5 to 120 minutes, preferably 10 to 100°C. minutes, more preferably 15 to 90 minutes.

The method for forming the fluorescent layer 26 as described above is just an example. The fluorescent layer 26 may be provided using a known method for laminating and curing prepreg, which is different from the above method.

・Figures 4 and 5
Solder 30 is placed in the opening (through hole) of the fluorescent layer 26 . Thereafter, the surface-mounted LED element 28 is placed on the solder 30. Then, the surface-mounted LED element 28 and the first copper foil 22A are soldered and electrically connected by melting the solder using, for example, a reflow method. The specific method and conditions for soldering are not particularly limited.
Incidentally, the solder 30 may be applied to the first copper foil 22A in advance.

A lighting device can be manufactured in the manner described above.
Incidentally, as shown in FIG. 5, a plurality of light emitting elements (surface-mounted LED elements 28) may be installed in the lighting device.

- Supplementary information In the step of providing the white layer 24 and the step of providing the fluorescent layer 26, a spacer (shim) may be used for the purpose of adjusting the film thickness. That is, the white layer 24 and the fluorescent layer 26 may be provided by heating, pressing, etc. using a spacer.

In addition, in FIGS. 3 and 4, depending on the material of the resin sheet and process conditions, the resin component softened when the sheet in the B-stage state is heated may be soldered to the surface-mounted LED element 28 in the cuprous foil 22A. It is conceivable that the paint may "bleed out" into the area where it should be attached. In this case, there is a possibility that the first copper foil 22A and the surface-mounted LED element 28 cannot be electrically connected.
One possible way to prevent this is to change the material of the resin sheet or the process conditions. Another method is to "protect" the part of the first copper foil 22A to which the surface-mounted LED element 28 is to be soldered by temporarily using a suitable member, such as a spring pin. It will be done. As another method, as described above, if the solder 30 is applied to the first copper foil 22A in advance, the softened resin component can theoretically be applied to the surface-mounted LED element 28 on the first copper foil 22A. It is possible to prevent "bleeding" onto the parts to be soldered.

- Regarding the surface-mounted LED element 28 In this embodiment, the light-emitting element (surface-mounted LED element 28) preferably does not include 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 out laterally or downwardly. However, in this embodiment, it is preferable that the light emitting element (surface-mounted LED element 28) does not include a reflector as shown in FIG. 6B.
By using a light emitting element without a reflector, light from the LED chip leaks laterally and downward. Then, the leaked light hits a portion of the fluorescent layer 26 indicated by α, and the portion indicated by α emits light. This further reduces glare and multiple shadow problems.

In the light-emitting element of FIG. 6A, the semiconductor light-emitting element 100 is arranged in a package-shaped part 108 formed by a substrate 102 and a reflector (housing) 104, and a sealing member 110 (light-transmitting resin) is placed in the package-shaped part 108. ) is filled. Substrate 102 can include wiring 112 .
In FIG. 6B, the same elements as in FIG. 2A are given the same reference numerals. In the light emitting element of FIG. 2B, a housing (reflector) is not used. After mounting the semiconductor light emitting device 100 as illustrated, the sealing member 110 can be formed by molding using a desired mold. Alternatively, the sealing member 110 may be prepared in advance and molded into a desired shape, and may be adhered to the substrate 102 so as to cover the semiconductor light emitting element 100.

Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and the present invention includes modifications, improvements, etc. within a range that can achieve the purpose of the present invention.

Embodiments of the present invention will be described in detail based on Examples and Comparative Examples. It should be noted that the present invention is not limited only to the embodiments.

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

<Manufacture of phosphor sheet using silicone resin>
In addition to the phosphor particles mentioned above, the following materials were prepared.
- Curable resin component: Dow Corning Toray silicone resin "RSN-0805" (silanol group content, silanol content (OH mass) 1%, silicon dioxide content 48 mass%, phenyl:methyl ratio = 1.1 :1, weight average molecular weight 200-300×10 ³ , xylene content, resin solid content 50% by weight)
・Fluidity modifier: Nippon Aerosil Co., Ltd.'s fumed silica AEROSIL 200
・Solvent: Butyl carbitol

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

A commercially available fiber base material (glass cloth) was impregnated with the above silicone resin varnish and dried in a vertical drying oven. After cooling, a through hole for connecting the light emitting element and the copper wiring was formed by punching. In this way, silicone resin phosphor sheets 2-1 to 2-4 were produced.
Incidentally, the drying conditions (temperature and time) were adjusted so that the silicone resin phosphor sheet was in a B-stage state. Further, based on the thickness of the phosphor layer (50 μm) described later, a fiber base material (glass cloth) having an appropriate thickness was selected.

<Manufacture of phosphor sheet using epoxy resin>
First, epoxy resin varnishes 2-1 to 2-4 having the following compositions were prepared.
・Bisphenol A type epoxy resin 640 parts by mass ・Bisphenol A novolac resin 25 parts by mass ・Ethyl methyl imidazole 0.2 parts by mass ・Phosphor particles in the amount shown in the table below ・Methyl ethyl ketone solvent The viscosity of the resin varnish is approximately 0.1 Ns/m amount that becomes ²

A commercially available fiber base material (glass cloth) was impregnated with the above epoxy resin varnish and dried at 135° C. for 5 minutes in a vertical drying oven. After cooling, a through hole for connecting the light emitting element and the copper wiring was formed by punching. In this way, epoxy resin phosphor sheets 2-1 to 2-4 in a B-stage state were produced.
Incidentally, the fiber base material (glass cloth) was selected to have an appropriate thickness based on the thickness (50 μm) of the phosphor layer described later.

<Manufacture of white sheet>
Except that titanium oxide/alumina mixed particles were used instead of the phosphor particles so that the amount in the nonvolatile components was 50 vol%, and the thickness of the glass cloth was changed as appropriate, A silicone resin-based white sheet was manufactured in the same manner as in <Manufacture of Phosphor Sheet Used>.
In addition, the above-mentioned <Epoxy An epoxy resin-based white sheet was manufactured in the same manner as in ``Manufacture of Phosphor Sheet Using Resin''.

<Production of lighting device (silicone type)>
Using the above phosphor sheet and the like, a lighting device was manufactured in which a plurality of CSPs were arranged on a phosphor layer at regular intervals. The manufacturing procedure is briefly shown below.
(1) As a material for the insulating substrate, a bonding sheet CS-3305A manufactured by Risho Kogyo Co., Ltd., which was laminated with copper foil on both sides, was prepared. This copper foil was etched to form a copper circuit on the first copper foil.
(2) The silicone resin white sheet described above was placed on the cuprous foil and pressed at a pressure of 20 kgf/cm ² and a temperature of 190° C. for 90 minutes. This formed a white layer with a thickness of 35 μm.
(3) The above silicone resin phosphor sheet (any one of 1-1 to 1-4) was placed on the white layer and pressed at a pressure of 20 kgf/cm ² and a temperature of 190° C. for 90 minutes. As a result, a phosphor layer with a thickness of 50 μm was formed.
(4) A commercially available CSP (WICOP SZ8-Y15-WW-C8, manufactured by Seoul Semiconductor Co., Ltd., product without reflector, color temperature 2200-2300K), which is a surface-mounted LED element, and cuprous foil (copper circuit). , electrically connected by soldering.

In addition, in the above (2) and (3), the position of the through hole in each sheet was set to be the position where the CSP and the first copper foil were connected in (4).

<Production of lighting device (epoxy system)>
Using the above phosphor sheet and the like, a lighting device was manufactured in which a plurality of CSPs were arranged on a phosphor layer at regular intervals. The manufacturing procedure is briefly shown below.
(1) As a material for the insulating substrate, a bonding sheet CS-3305A manufactured by Risho Kogyo Co., Ltd., which was laminated with copper foil on both sides, was prepared. This copper foil was etched to form a copper circuit on the first copper foil.
(2) The above white epoxy resin sheet was placed on the cuprous foil and pressed at a pressure of 20 kgf/cm ² and a temperature of 190° C. for 90 minutes. This formed a white layer with a thickness of 35 μm.
(3) The above epoxy resin phosphor sheet (any one of 2-1 to 2-4) was placed on the white layer and pressed at a pressure of 20 kgf/cm ² and a temperature of 190° C. for 90 minutes. As a result, a phosphor layer with a thickness of 50 μm was formed.
(4) A commercially available CSP (WICOP SZ8-Y15-WW-C8, manufactured by Seoul Semiconductor Co., Ltd., product without reflector, color temperature 2200-2300K), which is a surface-mounted LED element, and cuprous foil (copper circuit). , electrically connected by soldering.

<Evaluation: Color temperature conversion>
A current was applied to each lighting device produced above to cause 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 (device equipped with an integrating sphere) manufactured by Otsuka Electronics Co., Ltd. When the measured color temperature was 2000 to 2100K and the color temperature was converted by at least 100K from the color temperature of the CSP itself (2200 to 2300K), the color temperature conversion property was evaluated as "good".

As a result, the color temperature conversion properties of all the lighting devices produced were "good."

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

This application claims priority based on Japanese Patent Application No. 2022-049903 filed on March 25, 2022, and the entire disclosure thereof is incorporated herein.

20 Insulating substrate

22A Cuprous foil

22B Cupric foil 24 White layer 26 Fluorescent layer 28 Surface-mounted LED element 30 Solder 100 Semiconductor light emitting element 102 Substrate 104 Reflector (housing)
108 Package-shaped part 110 Sealing member 112 Wiring

Claims

A phosphor sheet comprising a thermosetting resin composition in a B-stage state, including phosphor particles and a curable resin component, and having a thickness of 20 to 150 μm.
The phosphor sheet according to claim 1,
A phosphor sheet in which the curable resin component contains at least one selected from the group consisting of epoxy resins and silicone resins.
The phosphor sheet according to claim 1 or 2,
A phosphor sheet with through holes.
The phosphor sheet according to any one of claims 1 to 3,
A phosphor sheet having a content of phosphor particles of 25 vol% or more and 60 vol% or less.
The phosphor sheet according to any one of claims 1 to 4,
The phosphor sheet includes phosphor particles in which the phosphor particles can convert blue light into light with a wavelength longer than the wavelength of the blue light.
The phosphor sheet according to any one of claims 1 to 5,
A phosphor sheet in which the median diameter D50 of the phosphor particles is 1 μm or more and 20 μm or less.
The phosphor sheet according to any one of claims 1 to 6,
A phosphor sheet in which two or more maxima are observed in the particle size distribution curve of the phosphor particles.
The phosphor sheet according to any one of claims 1 to 7,
In the particle size distribution curve of the phosphor particles, a maximum is observed 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.
The phosphor sheet according to any one of claims 1 to 8,
The phosphor particles include a CASN-based phosphor, a SCASN-based phosphor, a La 3 Si 6 N 11 -based phosphor, a Sr 2 Si 5 N 8 -based phosphor, a Ba 2 Si 5 N 8 -based phosphor, and an α-sialon-based phosphor. A phosphor sheet containing one or more selected from the group consisting of a phosphor, a β-sialon phosphor, a LuAG phosphor, and a YAG phosphor.
an insulating substrate;
A phosphor layer, which is a cured product of the phosphor sheet according to any one of claims 1 to 9, provided on one side of the insulating substrate;
A lighting device comprising: a light emitting element installed on a surface of the fluorescent layer opposite to the insulating substrate.
The lighting device according to claim 10,
The lighting device further includes a white layer between the insulating substrate and the fluorescent layer.
The lighting device according to claim 10 or 11,
A lighting device in which a plurality of the light emitting elements are installed.
The lighting device according to any one of claims 10 to 12,
A lighting device in which the light emitting element does not include a reflector.